Vasc Endovascular Surg. 2011 Oct;45(7):636-40Recanalization of failed autogenous conduit utilizing laser revascularizationChander RK, Oza P, Patel M, Balar N

1Department of Surgery, New York Medical College at Montefiore North Division,Bronx, NY, USA

The traditional approach for the treatment of restenosis of autogenous vein bypass has been revision of bypass with vein patch angioplasty, interposition jump graft, or thrombectomy procedures for those patients with extensive occlusive disease and limb-threatening ischemia. Endovascular intervention traditionally involves angioplasty of the graft; however, vessels with diffuse disease or extensive longitudinal lesions are generally difficult to revascularize utilizing this technique. Surgical revision of a threatened autogenous vein graft may carry a morbidity rate as high as 13.6%. We present a series of cases in which excimer laser atherectomy (LA) was used to recanalize an occluded autogenous saphenous vein bypass. Of the occluded vein bypasses failed angioplasty and were successfully atherectomized with LA measuring lengths of 35 and 30 cm, respectively. The infrainguinal has a 6-month follow-up, while the infragencular has a follow-up of 1 year, with resolution of presenting symptoms.

J Cardiovasc Med (Hagerstown). 2011 Jul 6. [Epub ahead of print]Excimer laser coronary angioplasty with manual thrombus aspiration for a case of very late stent thrombosis of sirolimus-eluting stentNiccoli G, Minelli S, Cosentino N, Crea F

Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy

Very late stent thrombosis occurring after drug-eluting stent implantation is a rare complication. However, it is often associated with poor outcome. Manual thrombectomy has been shown to lower the rate of distal embolization in the case of ST-elevation myocardial infarction of native coronary arteries. However, the presence of abundant thrombus material may lead to manual thrombus aspiration failure. Here, we describe the case of a patient with acute myocardial infarction due to stent thrombosis of a sirolimus-eluting stent occurring 50 months after stent deployment showing abundant thrombus material, which led to manual thrombus aspiration failure and was then successfully treated by excimer laser coronary angioplasty. In these cases, excimer laser coronary angioplasty may be useful due to its ability to dissolve thrombus.

J Interv Cardiol. 2011 Jun 28. Epub ahead of printA Complex Case of Angulated and Bifurcated Lesion Facilitated by Excimer LaserCoronary AngioplastyNiccoli G, Minelli S, Cosentino N, Crea F

Institute of Cardiology, Catholic University of the Sacred Heart, Rome, Italy.

Angulated lesions have been shown to be associated with abrupt closure or periprocedural myocardial injury. In particular, when disease is present at the level of the angulated or bifurcated lesion, balloon dilatation may help in wire crossing but it may also cause branch occlusion. Several methods and devices have been described to manipulate coronary guidewires across angulated and bifurcated lesions. This case report describes a highly angulated coronary bifurcated lesion where, after the failure of multiple wires to cross the lesion toward the main branch, it was successfully crossed after excimer laser debulking, whichfacilitated the wire crossing into the main branch, without causing branch occlusion.

Conf Proc IEEE Eng Med Biol Soc. 2010;2010:1618-21

The laser driven short-term heating balloon catheter: Relation between the chronic neointimal hyperplasia formation and thermal damage to arterial smooth muscle cellsShimazaki N, Hayashi T, Kunio M, Igami Y, Arai T, Sakurada M

Graduate School of Fundamental Science and Technology, Keio University (Japan).shima_natsu@arai.appi.keiro.ac.jp

We proposed a novel laser-driven short-term heating angioplasty to realiz restenosis-suppressive angioplasty for peripheral artery disease. In this study, we investigated the chronic intimal hyperplasia formation after the short-term heating dilatation in vivo, as well as the thermal damage calculation on arterial smooth muscle cells (SMCs). The prototype short-term heating balloon catheter with 5.0, 5.5, 6.0 mm φ in balloon diameter and 25 mm in balloon length were employed. The short-term heating dilatation was performed in porcine iliac arteries with dilatation conditions of 75°C (N=4) and 65°C (N=5) as peak balloon temperature, 18 ± 4s as heating duration, 3.5 atm as balloon dilatation pressure. Four weeks after the balloon dilatation, the balloon-dilated artery segments were extracted and were stained with HE and picrosirius red for histological observation. In the case of 75°C as the peak balloon temperature, neointimal hyperplasia formation was significantly reduced. In this case, the SMCs density in the artery media measured from the HE-stained specimen was 20% lower than that in the reference artery. According to the thermal damage calculation, it was estimated that the SMCs lethality in artery media after the short-term heating angioplasty was 20% in the case of 75°C as the peak balloon temperature. We demonstrated that the short-term heating dilatation reduced the number of SMCs in artery media. We think this SMCs reduction might contribute to the suppression of chronic neointimal hyperplasia.

Conf Proc IEEE Eng Med Biol Soc. 2010;2010:1614-7Development of selective laser treatment techniques using mid-infrared tunablenanosecond pulsed laserIshii K, Saiki M, Hazama H, Awazu K

Medical Beam Phisics Laboratory, Division of Sustainable Energy and EnvironmentalEngineering, Graduate School of Engineering, Osaka University, 565-0871, Japanishii-k@see.eng-osaka-u.ac.jp

Mid-infrared (MIR) laser with a specific wavelength can excite the corresponding biomolecular site to regulate chemical, thermal and mechanical interactions tobiological molecules and tissues. In laser surgery and medicine, tunable MIRlaser irradiation can realize the selective and less-invasive treatments and the special diagnosis by vibrational spectroscopic information. This paper showed anovel selective therapeutic technique for a laser angioplasty of atherosclerotic plaques and a laser dental surgery of a carious dentin using a MIR tunablenanosecond pulsed laser.

Int J Cardiol. 2010 Nov 19;145(2):251-4. Epub 2009 Sep 13Crossing of a calcified "balloon uncrossable" coronary chronic total occlusion facilitated by a laser catheter: a case report and review recent four years' experience at the ThoraxcenterShen ZJ, García-García HM, Schultz C, van der Ent M, Serruys PW

Failure to cross with a balloon is a well recognised cause of failure to recanalise a chronic total occlusion (CTO) despite successfully positioning a guidewire into the distal true lumen. One technique that is infrequently used currently is excimer laser assisted coronary intervention. We report a patient with CTO in whom in the fourth attempt, the operators succeeded by using a laser catheter. Also, we review the cases treated with laser catheter in our institution during these recent 4 years. The laser catheter can be useful in selected patients including those with CTO where a balloon would not pass despite a guidewire in the distal true lumen.

Int J Cardiol. 2010 Nov 19;145(2):e60-3. Epub 2009 Jan 30A case of very late thrombosis of bare metal stent successfully treated with excimer laser coronary angioplasty

Larosa C, Ricco A, Cosentino N, Marino M, Mongiardo R, Niccoli G

Late thrombosis occurring after bare metal stent (BMS) implantation is a rare complication. However, it is often associated with poor outcome. Mechanisms underlying BMS thrombosis may differ from those underlying drug eluting stent thrombosis. In particular, severe instent restenosis may trigger thrombus formation. This case report describes a very late thrombosis of BMS occurring on an in-stent restenosis. After failure of manual thrombectomy, the case was successfully faced by Excimer Laser Coronary Angioplasty (ELCA). Cases like this may be successfully treated by devices like ELCA combining debulking and thrombus removal capabilities.

Am J Cardiol. 2010 Oct 15;106(8):1113-7Usefulness of intravascular low-power laser illumination in preventing restenosis after percutaneous coronary interventionDerkacz A, Protasiewicz M, Poreba R, Szuba A, Andrzejak R

Department of Internal Medicine, Wroclaw Medical University, Wroclaw, Poland.aderkacz@chirs.am.wroc.pl

Despite the several years of studies, no factor that could reduce the restenosis rate without significant limitations has been introduced. The aim of the present study was to evaluate the influence of low-power 808-nm laser illumination of coronary vessels after percutaneous angioplasty in preventing restenosis. The procedure of laser intravascular illumination was performed on 52 patients (laser group), and another 49 patients formed the control group. All patients were monitored for major adverse cardiac events (MACE) at the 6- and 12-month follow-up points. The MACE rate after 6 and 12 months was 7.7% in the laser group at both points. The MACE rate was 14.3% and 18.5% at 6 and 12 months of follow-up in the control group, respectively (p = NS). Follow-up coronary angiography was performed after 6 months. The difference in the restenosis rate was insignificant (15.0% vs 32.4%); however, significant differences were observed in the minimal lumen diameter (2.18 ± 0.70 vs 1.76 ± 0.74 mm; p < 0.05), late lumen loss (0.53 ± 0.68 vs 0.76 ± 0.76 mm; p < 0.01), and the late lumen loss index (0.28 ± 0.39 vs 0.46 ± 0.43; p < 0.005) in favor of the laser group. In conclusion, the new therapy seemed effective and safe. Marked differences between late loss, late loss index, and minimal lumen diameter were observed. The late lumen loss in the laser group was only slightly greater than that in studies of drug-eluting stents, and MACE rate remained within very comparable ranges. This suggests that intravascular laser illumination could bring advantages comparable to those of drug-eluting stents without the risk of late thrombosis.

Eur J Radiol. 2010 Jul;75(1):48-56. Epub 2010 May 7Angioplasty of the pelvic and femoral arteries in PAOD: results and review of the literatureBalzer JO, Thalhammer A, Khan V, Zangos S, Vogl TJ, Lehnert T

Dept. for Radiology and Nuclear medicine, Catholic Clinic Mainz, An der Goldgrube 11, 55131 Mainz, Germany. balzerjo@t-online.de

Purpose: Evaluation of percutaneous recanalization of obstructed iliac as well as superficial femoral arteries (SFAs) in patients with peripheral arterial obstructive disease (PAOD)

Material and methods : The data of 195 consecutive patients with 285 obstructions of the common and or external iliac artery as well as the data of 452 consecutive patients with 602 long occlusions (length>5 cm) of the SFA were retrospectively analyzed. The lesions were either treated with percutaneous transluminal angioplasty (PTA) or Excimer laser assisted percutaneous transluminal angioplasty (LPTA). Overall 316 stents were implanted (Nitinol stents: 136; stainless steel stents: 180) in the iliac artery and 669 stents were implanted (Nitinol stents: 311; Easy Wallstents: 358) in the SFA. The follow-up period was 36-65 months (mean 46.98+/-7.11 months) postinterventionally using clinical examination, ABI calculation, and color-coded duplex sonography. Patency rates were calculated on the basis of the Kaplan-Meier analysis.

Results : The overall primary technical success rate was 97.89% for the iliac arteries and 92.35% for the SFA. Minor complications (hematoma, distal emboli and vessel dissection) were documented in 11.79% for the iliac arteries and 7.97% for the SFA. The primary patency rate was 90.3% for the iliac and 52.8% for the SFA after 4 years. The secondary patency rate was 96.84% for the iliac and 77.8% for the SFA after 4 years.

Conclusions : Percutaneous recanalization of iliac and superficial femoral artery obstructions is a safe and effective technique for the treatment of patients with PAOD. By consequent clinical monitoring high secondary patency rates can be achieved. The use of a stents seems to result in higher patency rate especially in the SFA when compared to the literature in long-term follow-up.

J Cardiovasc Surg (Torino). 2010 Apr;51(2):233-43Update on the TURBO BOOSTER spectranetics laser for lower extremity occlusivediseaseMicari A, Vadalà G, Biamino G

GVM Care and Research, Palermo, Italy. antoniomicari@tiscali.it

In the last two decades the endovascular treatment of peripheral arterial occlusive disease (PAOD) has gained a widespread and predominant role. New technologies have developed in the last years as atherectomy devices, self expandible nitinol stents, drug eluting devices (stent and balloons), absorbable stents. In recent years, growing interest has been dedicated to laser technology due to device improvements and literature data reporting safety and efficacy of excimer laser. The role of this new endovascular technique for the treatment ofatherosclerotic arterial diseases should be considered with regard to two fields of interest: the claudicatio intermittens (CI) and the critical limb ischemia (CLI). A 20-year history with medical lasers has proven that not all lasers are equal. Lasers used and studied in the late 1980s and 1990s had poor outcomes due to inappropriate laser selection and undefined laser techniques. Over the last 10 years, multicenter studies with the excimer laser confirm that case selection,appropriate utilization of equipment, application of safe lasing techniques, and knowledge of indications and contraindications, all contribute to the successful application of laser-assisted angioplasty in complex coronary and peripheral artery disease. If applied properly, the Excimer Laser is a useful technique to transform complex obstructive arterial disease into more treatable lesions, improving the results of endovascular treatment and lowering the threshold of intervention for ''untreatable'' patients. New larger studies are requested to assess the definitive role of this technique in PAD treatment and limb salvage.This review will discuss the Laser Phisics and application in PAD along with the clinical data available to support the Excimer Laser as a reliable technology forendovascular intervention.

Eur J Vasc Endovasc Surg. 2010 Feb;39(2):234-8. Epub 2009 Nov 25Excimer laser ablation in the treatment of total chronic obstructions in criticallimb ischaemia in diabetic patients. Sustained efficacy of plaque recanalisation in mid-term resultsSerino F, Cao Y, Renzi C, Mascellari L, Toscanella F, Raskovic D, Tempesta P,Bandiera G, Santini A

Department of Vascular Surgery, Istituto Dermopatico dell'Immacolata, IRCCS,Rome, Italy. f.serino@idi.it

This prospective study aims to evaluate the impact of the excimer laser technology as the first-line endovascular treatment of critical limb ischaemia (CLI) in diabetic patients. The protocol allowed the use of laser ablation of obstructive lesions when conventional endoluminal guidewire crossing of the plaque was unsuccessful. We extrapolate the data of consecutive patients treated, who completed at least 12 months of follow-up, extending the observation to a 26-month time frame. During this period, 67 diabetic patients with CLI were brought to the Cath Lab for 'operative angioplasty' and to be treated with endovascular techniques. Of the 67 cases, laser was used on 35 patients to treat 51 lesions. All patients had type C or D occlusive lesions, according to the TACS II classification, showing a single type D plaque or multiple tandem C/D occlusive plaques ranging from 4 to 23 cm in length. The immediate clinicalsuccess, defined as restored direct arterial flow to the foot, was 88.2%. The lesions were successfully crossed by laser in 45 out of 51 attempts. Stents were required in 25% of the patients with 21% lesions. Patency rates were assessed using the Kaplan-Meier survival curves. The patency rates of the successfully treated lesions (freedom from target lesion revascularisation) were 96.6% at 12 months and 82.7% at 24 months. Limb-salvage rate at 12 and 24 months were 100% and 94%, respectively. Our study showed that the excimer laser-assisted angioplasty, when feasible, is effective in granting event-free survival in CLIpatients with diabetes, and that endoluminal-driven atherectomy allows long-term success in reducing the need of stents in the lower limb arteries.

Acta Bioeng Biomech. 2009;11(3):11-8Flexibility and trackability of laser cut coronary stent systemsSzabadíts P, Puskás Z, Dobránszky J

Budapest University of Technology and Economics, Department of Materials Science and Engineering, Budapest, Hungary. szabadits@freemail.hu

Coronary stents are the most important supports in present day cardiology. Flexibility and trackability are two basic features of stents. In this paper, four different balloon-expandable coronary stent systems were investigated mechanically in order to compare their suitability. The coronary stent systems were assessed by measurements of stent flexibility as well as by comparison of forces during simulated stenting in a self-investigated coronary vessel model. The stents were cut by laser from a single tube of 316L stainless steel or L-605 (CoCr) cobalt chromium alloy. The one-and four-point bending tests were carried out to evaluate the stent flexibility E x I (Nmm(2)), under displacement control in crimped and expanded configurations. The flexibility of stents would be rather dependent on the design than on raw material. In general a more flexible stent needs lower tracking force during the implantation. The L-605 raw material stents need lower track force to pass through in the vessel model than the 316L raw material stents. The sort and long stents passed through the curved vessel model in different ways. The long stents nestled to the vessel wall at the outer arc and bent, while the short stents did not bend in the curve, only the delivery systems bent.

J Endovasc Ther. 2009 Dec;16(6):665-75Excimer laser recanalization of femoropopliteal lesions and 1-year patency: results of the CELLO registryDave RM, Patlola R, Kollmeyer K, Bunch F, Weinstock BS, Dippel E, Jaff MR, Popma J, Weissman N; CELLO Investigators

Harrisburg Hospital, Harrisburg, Pennsylvania 17101, USA. rdintervention@yahoo.com

Purpose: To evaluate the safety and efficacy of a modified laser catheter designed for the endovascular treatment of peripheral artery disease (PAD) affecting the superficial femoral artery (SFA) and proximal popliteal artery.

Methods: The CliRpath Excimer Laser System to Enlarge Lumen Openings (CELLO) study was a single-arm, prospective registry conducted at 17 investigational sites in the United States. The primary endpoint was the reduction in index lesion percent diameter stenosis (% DS) measured by Doppler ultrasound following laser ablation prior to any adjunctive therapy. The primary safety endpoint was major adverse events at 6 months. Sixty-five patients (39 men; mean age 68.3+/-10.1 years) with intermittent claudication, stenotic lesions >70% by visual assessment, a reference vessel diameter >or=4.0 and <or=7.0 mm, and a total lesion length >or=1.0 and <or=15.0 cm underwent laser-assisted recanalization with optional balloon angioplasty (BA) or BA + stenting. Sixty-five de novo lesions (5.6+/-4.7 cm) in 13 occluded and 52 stenotic arteries were treated.

Results: Laser ablation reduced the % DS from 77%+/-15% at baseline to 34.7%+/-17.8%, which was reduced to 21%+/-14.5% after adjunctive therapy with BA (n = 42, 64.6%) or BA + stenting (n = 15, 23.3%). Eight (12.3%) patients did not receive post laser adjunctive therapy. Patency rates (% DS <50%) were 59% and 54% at 6 and 12 months, respectively. Target lesion revascularization was not required in 76.9% of CELLO participants within the 1-year follow-up. There were no major adverse events. The study cohort demonstrated a statistically significant improvement in the walking impairment and functional status assessments during follow-up.

Conclusions :The data validate the safety and efficacy of the investigational device, with a high clinical success rate and 12-month data indicating freedom from reintervention in the majority of patients treated.

J Endovasc Ther. 2009 Dec;16(6):676-9Taking femoropopliteal excimer laser photoablation therapy to the next level: defining the role of the TURBO-Booster guiding catheter in the CELLO registryShammas NW

Midwest Cardiovascular Research Foundation, Davenport, Iowa, USA. shammas@mchsi.com

Peripheral Interventions, Presbyterian Heart Institute, Dallas, Texas, USA. tdas@civadall

After nearly 2 decades of research and experimentation with laser-assisted angioplasty, the xenon-hydrogen chloride excimer laser emerged as the laser device best suited for the treatment of peripheral artery disease. Emitting light at a wavelength of 308 nm, this laser utilizes a non thermal mechanism of action to ablate plaque and thrombus in powerful discrete pulses. The excimer laser is particularly useful for the treatment of complex conditions, such as long chronic occlusions in the superficial femoral artery and in those patients with below-the-knee disease and critical limb ischemia who may not be good candidates for bypass surgery. A number of investigators have noted that the excimer laser will often uncover distinct, more focal lesions in what appears to be an extensive and complex occlusion, potentially simplifying treatment of these segments. The Laser Angioplasty for Critical Limb Ischemia phase 2 trial, a prospective registry of 145 patients at 11 US and 3 German sites, achieved good procedural success (86%) and an excellent 6-month limb salvage rate (93%). A new specialized deflecting sheath designed to direct excimer ablation in blockages of the larger main arteries above the knee has produced clinical improvement in a single-center feasibility study and a 16-center prospective registry. Less promising results were reported in a single-center real-world retrospective registry, warranting careful case selection with this device for patients with diabetes and renal failure.

Lasers Med Sci. 2009 Nov;24(6):955-60. Epub 2009 Feb 24Excimer laser debulking for percutaneous coronary intervention in left main coronary artery diseaseTopaz O, Polkampally PR, Mohanty PK, Rizk M, Bangs J, Bernardo NL

Division of Cardiology, McGuire Veterans Affairs Medical Center, Virginia Commonwealth University School of Medicine, Richmond, VA 23249, USA. On.Topaz@va.gov

Excimer laser has been successfully applied to complex atherosclerotic plaques in acute coronary syndromes; however, its role in debulking in left main coronary artery disease has not been fully explored. Details of a series of 20 patients who underwent excimer laser revascularization of a spectrum of left main coronary artery lesions are presented. Twenty symptomatic patients who received excimer laser debulking were examined for procedural outcome and follow up results. The left main coronary artery was characterized as protected, semi-protected, poorly protected, or unprotected, depending on the presence or absence of patent bypass grafts to the left anterior descending (LAD) and circumflex (CX) arteries. A fully protected left main coronary artery (LMCA) was present in only 20% of the patients. The target lesions included 11(55%) distal LMCA stenoses, six (30%) ostial stenoses, and one (5%) mid-portion lesions. Two (10%) patients had in-stent re-stenosis of the entire length of the LMCA. Small (0.7 mm-1.4 mm) excimer laser catheters were mostly used. A relatively high number of laser energy pulses (1,334 +/- 643) were required to achieve adequate debulking. Successful LMCA intervention was performed in 19 (95%) patients, while in-hospital complications occurred in only one (5%) patient. Subacute/late stent thrombosis developed 3 months after the procedure in one patient, and two patients died from non-cardiac causes during follow-up. Lesions in LMCAs can be revascularized in selected patients by laser debulking and adjunct stenting. Inadequate protection by bypass grafts and decreased left ventricular function do not contradict utilization of excimer laser. Small laser catheters and high energy levels are required during laser debulking of stenoses of left main coronary arteries.

Lasers Surg Med. 2009 Nov;41(9):622-7Utilization of excimer laser debulking for critical lesions unsuitable for standard renal angioplastyTopaz O, Polkampally PR, Topaz A, Polkampally CR, Jara J, Rizk M, McDowell K, Feldman G

Division of Cardiology and Nephrology, McGuire Veterans Affairs Medical Center,MCV/Virginia Commonwealth University School of Medicine, Richmond, Virginia23249, USA. on.topaz@med.va.gov

Background: The energy emitted by ultraviolet laser is avidly absorbed in atherosclerotic plaques. Conceptually, it could be applied for debulking of selected atherosclerotic renal artery stenoses. We describe early experience with revascularization of critical renal artery lesions

deemed unsuitable for standard renal angioplasty. Institutional Review Board permission to conduct the data analysis was obtained.

Methods: Among 130 percutaneous renal artery interventions with balloon angioplasty and adjunct stenting, there were 12 (9%) patients who underwent laser debulking prior to stenting. These patients presented with critical (95+/-3.5% stenoses) lesions (11 de novo, 1 stent restenosis) deemed unsuitable for standard renal angioplasty because of marked eccentricity and presence of thrombus. Indications for intervention included preservation of kidney function, treatment of uncontrolled hypertension, management of congestive heart failure, and treatment of unstable angina. Blood pressure and estimated glomerular filtration rate (eGFR) were measured pre- and 3 weeks post-intervention.

Results: A baseline angiographic stenosis of 95+/-3.5% was reduced to 50+/-13% with laser debulking. There were no laser-induced complications. Post-stenting the angiographic residual stenosis was 0%. The mean gradient across the lesions was reduced from baseline 85+/-40 to 0 mmHg. A normal post-intervention antegrade renal flow was observed in all patients. Baseline mean systolic BP of 178+/-20 mmHg decreased to 132+/-12 mmHg (P<0.0001) and mean diastolic pressure of 85+/-16 mmHg reduced to 71+/-9 mmHg (P = 0.01). A pre-intervention mean eGFR of 47.7+/-19 ml/min/1.73 m(2) increased to 56+/-20.4 ml/min/1.73 m(2) (P = 0.05) post-procedure. The interventions were not associated with major renal or cardiac adverse events. During follow-up one patient developed transient contrast-inducednephropathy.

Conclusions: Debulking of select renal artery stenoses with laser angioplasty followed by adjunct stenting is feasible. Further prospective, randomized studies will be required to explore the role of debulking and laser angioplasty in renal artery revascularization.

J Endovasc Ther. 2009 Oct;16(5):619-23Retrograde transpopliteal recanalization of chronic superficial femoral artery occlusion after failed re-entry during antegrade subintimal angioplastyNoory E, Rastan A, Schwarzwälder U, Sixt S, Beschorner U, Bürgelin K, Neumann FJ, Zeller TDepartment of Angiology, Herz-Zentrum Bad Krozingen, Germany elias.noory@herzzentrum.de

Purpose : To evaluate the acute success and clinical impact of retrograde transpopliteal access for subintimal recanalization of superficial femoral artery (SFA) and proximal popliteal artery (PA) occlusions after failed attempts to re-enter the true lumen in the antegrade femoral approach.

Methods: From 2002 to 2007, 56 patients (43 men; mean age 68+/-9 years, range 43-87) with stable chronic peripheral artery disease (Rutherford category 2 to 5) were treated with antegrade subintimal angioplasty that could not be completed owing to re-entry failure. Mean occlusion length was 17+/-7 cm (range 4-32), including 13 TASC II A (23.2%), 10 TASC II B (17.8%), 16 TASC II C (28.5%), and 17 TASC II D (30.3%) lesions. After re-entry to the true lumen failed in the antegrade approach, including predilation of the false channel, all patients were turned to a prone position, and a 5-F or 6-F sheath was placed into the mid segment of the PA under fluoroscopic guidance. Retrograde wire passage was attempted with a 0.035-inch hydrophilic guidewire.

Results: Fifty-five (98.2%) of 56 procedures were finished successfully with a residual stenosis of <30%; the 1 failure was due stent deformation within the occluded segment that could not be passed from either an antegrade or retrograde access. In all interventions, balloon angioplasty was performed; provisional stenting was done in 40 (71.4%). In 3 (5.3%) lesions, additional excimer laser atherectomy were performed. Six (10.7%) complications occurred, including 1 arteriovenous fistula from the PA to the popliteal vein and 1 sealing device induced PA occlusion. The mean ankle-brachial index increased from 0.44+/-0.26 to 0.86+/-0.23. The restenosis rate after 12 months was 54.9%.

Conclusion: Failed antegrade attempts to recanalize chronic total occlusions of the SFA and proximal PA can be salvaged using a retrograde popliteal access, with a low complication rate, as an alternative to using a re-entry device. However, durability of the intervention using current interventional tools is limited.

Semin Dial. 2009 Sep-Oct;22(5):580-3. Epub 2009 Sep 9Excimer laser assisted angioplasty in hemodialysis access intervention

Yevzlin AS, Urbanes A

Department of Medicine, Section of Cardiovascular Medicine, University ofWisconsin School of Medicine and Public Health, Madison, Wisconsin 23713, USAasy@medicine.wisc.edu

A case is described in which an excimer laser is used to assist angioplasty of a severe central venous lesion that is refractory to conventional techniques. Modern laser technology uses the ultraviolet (UV) spectral region to generate nanosecond pulses of energy. This results in photoablation, which is the process by which energy photons cause molecular bond disruption, while minimizing thermal damage to the surrounding vascular tissues. Further investigation of excimer laser assisted angioplasty in the setting of hemodialysis access intervention is needed to rigorously define its potential role. In occlusive disease where no conventional alternative is available, however, laser therapy is a viable option.

Vasc Endovascular Surg. 2009 Aug-Sep;43(4):370-3. Epub 2009 Apr 7Excimer laser for debulking and lysing chronic venous thrombi and occlusionsMoritz MW, Ombrellino M, Agis H

Vein Institute of New Jersey, Morristown, New Jersey 07960, USA. mmoritz@vinj.us

Lysis of deep venous thrombotic obstruction in the extremities has been shown to decrease the frequency and severity of symptoms of postthrombotic syndrome. However, for those lesions that contain organized thrombus, the use of conventional methods to lyse thrombus is less successful than for acute thrombus. The authors here present a novel method for treatment of older, organized thrombus using excimer laser. This technique can obviate some of the limitations of the other methods and allow effective treatment when other methods fail. It has been used successfully in 19 patients with excellent results and is recommended for those cases.

J Endovasc Ther. 2009 Apr;16(2 Suppl 2):II98-104Excimer laser-assisted angioplasty for infrainguinal artery diseaseDas TS

Peripheral Interventions, Presbyterian Heart Institute, Dallas, Texas, USA.tdas@civadallas.com

After nearly 2 decades of research and experimentation with laser-assisted angioplasty, the xenon-hydrogen chloride excimer laser emerged as the laser device best suited for the treatment of peripheral artery disease. Emitting light at a wavelength of 308 nm, this laser utilizes a nonthermal mechanism of action to ablate plaque and thrombus in powerful discrete pulses. The excimer laser is particularly useful for the treatment of complex conditions, such as long chronic occlusions in the superficial femoral artery and in those patients withbelow-the-knee disease and critical limb ischemia who may not be good candidates for bypass surgery. A number of investigators have noted that the excimer laser will often uncover distinct, more focal lesions in what appears to be an extensive and complex occlusion, potentially simplifying treatment of these segments. The Laser Angioplasty for Critical Limb Ischemia phase 2 trial, a prospective registry of 145 patients at 11 US and 3 German sites, achieved good procedural success (86%) and an excellent 6-month limb salvage rate (93%). A new specialized deflecting sheath designed to direct excimer ablation in blockages ofthe larger main arteries above the knee has produced clinical improvement in a single-center feasibility study and a 16-center prospective registry. Less promising results were reported in a single-center real-world retrospective registry, warranting careful case selection with this device for patients with diabetes and renal failure.

J Endovasc Ther. 2009 Apr;16(2):197-202Distal embolic event protection using excimer laser ablation in peripheralvascular interventions: results of the DEEP EMBOLI registryShammas NW, Coiner D, Shammas GA, Christensen L, Dippel EJ, Jerin M

Midwest Cardiovascular Research Foundation, Davenport, Iowa 52803, USA.shammas@mchsi.com

Purpose: To report the results from a single-center prospective registry (DEEP EMBOLI) established to evaluate distal embolization during percutaneous lower extremity interventions using excimer laser ablative therapy.

Methods: Elective patients with infra inguinal occlusive disease were eligible forthis registry if the lesion(s) met one or more of these angiographic criteria:(1) moderate or severe calcification of any length, (2) total occlusions of any length, (3) a filling defect, (4) irregular (ulcerated) lesions at least 30 mm in length, and/or (5) smooth, non-ulcerated lesions at least 50 mm in length. In all, 20 patients (15 women; mean age 70.9+/-10.8 years) with 28 lesions (de novo 13, restenotic 15) were enrolled and underwent treatment with laser atherectomy. Spider Fx filters were utilized before laser treatment in 18 of 20 patients andbefore final definitive treatment with angioplasty +/- stenting in all 20 patients. The primary angiographic outcome was a residual narrowing of <30% or30% to 50% with <20 mmHg gradient across lesion after final treatment. The primary safety endpoint was the embolization rate produced by the laser based on the presence of clinically significant (>or=2 mm long) macro debris in the filter.

Results: Adjunctive angioplasty and stenting were performed in 27 (96.4%) and 17 (60.7%) lesions, respectively. All filters were deployed and retrieved successfully, with no complications. The primary angiographic endpoint was met in100% of patients. Macrodebris was found in 12 (66.7%) of 18 patients after treatment with the laser [4 (22.2%) filters with clinically significant emboli]and in 7 (35%) of 20 patients after adjunctive treatment [4 (20.0%) clinically significant emboli]. One (5.0%) distal embolization occurred after filter removal prior to completion of definitive treatment.

Conclusion: Embolization does occur with laser photoablation in the lower extremity, but the rate of clinically significant macro debris is low (approximately 20%) and similar to that found after angioplasty and stenting. Embolic filter protection appears to be very effective in capturing macrodebris, and its use is associated with good acute angiographic outcome. Problems with filter retrieval were not encountered.

Minim Invasive Neurosurg. 2008 Dec;51(6):324-8. Epub 2008 Dec 5A laser-induced liquid jet catheter system: a novel endovascular device for rapid and reliable fibrinolysis in acute cerebral embolismHirano T, Nakagawa A, Ohki T, Uenohara H, Takayama K, Tominaga T

1Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.

Objective : Mechanical removal of intravascular clots in addition to administration of tissue plasminogen activator are both desirable for improved outcome in acute embolic stroke. We have developed a novel endovascular catheter system for rapid and reliable mechanical recanalization of cerebral embolisms with little or no requirement for fibrinolytic agents. Here, we describe the evaluation of this device in vitro.

Materials : Pulsed liquid jets were generated and ejected from the catheter exit by accelerating cold physiological saline (4 degrees C, 40 mL/h) using the energy of a pulsed holmium:yttrium-aluminum-garnet (YAG) laser (3 Hz, 1.2 W). Accessibility beyond the tortuous cavernous portion of the internal carotid artery to the M1 and A1 regions was confirmed using a transparent model of the human cerebral artery. Mechanical characteristics of the liquid jets were evaluated with a high-speed camera. Liquid jets of physiological saline or urokinase solution (1,200 IU/mL) were exposed to artificial thrombi made of human blood under temperature monitoring. Remnants of thrombi were collected and incubated at 37 degrees C for 10 min for estimation of fibrinolysis rates.

Results : The jet velocity (maximum: 5 m/s) was controlled by changing the laser energy. The fibrinolysis rates (mean+/-SD) after exposure to jets of saline or urokinase solution for 45 s were 62.2+/-16.4 and 94.0+/-3.4%, respectively, and were significantly better than the rate of 8.1+/-2.0% with administration of urokinase alone. The local temperature rise was less than 8 degrees C.

Conclusions: The results show that the laser-induced liquid jet catheter system may be a powerful tool for mechanical destruction of emboli and augmentation of the effect of fibrinolytic agents beyond the tortuous part of the internal carotid artery.

Conf Proc IEEE Eng Med Biol Soc. 2008;2008:3661-3The laser driven heating balloon catheter: vessel dilatation characteristics.Shimazaki N, Mizukami G, Tokunaga H, Kaneko K, Arai T

School of Fundamental Science and Technology, Graduate School of Science andTechnology, KEIO University, Japan

We studied on the dilatation characteristics of our new angioplasty, photo-thermodynamic balloon (PTDB) angioplasty, which provides short-term heating (15s, 50-70degrees C) dilatation by the combination of laser heat generator and fluidperfusion. In this study, we employed the ex vivo experiments to demonstrate the feasibility of our PTDB angioplasty with extracted porcine carotid artery.Balloon temperature and heating duration were easily controlled with the laserpower and irradiation duration. Arterial dilatation was performed with theprototype PTDB catheter (3mm in diameter) ex vivo, sufficient dilation wasattained with low dilatation pressure (2atm) that is lower than the limitpressure of elastic region (8atm in this case). The principal of our PTDBangioplasty that was based on the experimental results was dilatation in elastic region, while traditional POBA was accompanied with plastic deformation ofartery. It is predicted that successful way of PTDB dilatation was attributed to collagen softening. Collagen coagulation and/or restructure after the heatingdilatation might suspend the dilated arterial lumen. We demonstrated thefeasibility of our PTDB angioplasty. We think collagen denaturation degree may be the important factor in this methodology

Brain Nerve. 2008 Sep;60(9):1073-6Excimer laser angioplasty for subclavian artery stenosis--case reportEndo H, Yoshida K, Mitsudo K, Takasaki M, Yamagata S

Department of Neurosurgery, Kurashiki Central Hospital, Japan

Endovascular angioplasty for subclavian artery stenosis is effective and less invasive than other methods; however, it is difficult to advance guidewires or balloon catheters through severely stenotic lesions. We report a case of subclavian artery stenosis treated with excimer laser angioplasty. A 58-year-old man with hypertension and hyperlipidemia was admitted to a hospital with different blood pressure in each arm. A CT scan revealed left subclavian artery stenosis, and the patient was transferred to our hospital. An angiogram revealed a severely stenotic lesion in his left subclavian artery, representing subclavian steal phenomenon. Endovascular angioplasty was performed under local anesthesia with embolic protection for the left vertebral artery. The guidewire successfully crossed the lesion, and stepwise balloon angioplasty was performed using increasing balloon sizes from 1.5 to 2.0 mm; however, the next size balloon catheter could not cross the lesion, and we therefore decided to use an excimer laser catheter. After laser ablation, revascularization was performed via stent placement. The patient's symptoms and subclavian steal phenomenon improved, and the post-operative course was uneventful. Excimer laser angioplasty appears to be effective in the treatment of occlusive lesions that cannot be crossed using a balloon catheter.

J Cardiovasc Surg (Torino). 2008 Jun;49(3):329-40Excimer laser assisted angioplasty for complex infrainguinal peripheral artery disease: a 2008 updateTan JW, Yeo KK, Laird JR

UC Davis Vascular Center, University of California, Davis Medical Center, Sacramento, CA, USA

Conventional percutaneous transluminal angioplasty (PTA) for complex or long segment infrainguinal occlusive arterial disease is limited by elastic recoil, dissection and restenosis, with high rates of intermediate and long term restenosis . Debulking with excimer laser has been advocated as a useful adjunctive strategy to improve procedural success and long term patency. This paper reviews the technological development of excimer laser, the studies supporting its use in infrainguinal arterial disease, effective and safe lasing techniques, its advantages, limitations and disadvantages. Case examples will be presented to illustrate its use in infrainguinal arterial disease. Although randomized controlled trials are lacking, existing registry and case series studies suggest efficacy of the excimer laser-assisted PTA for complex infrainguinal arterial disease, including patients with critical limb ischemia.

Catheter Cardiovasc Interv. 2008 May 1;71(6):803-7High energy excimer laser to treat coronary in-stent restenosis in an underexpanded stent

Noble S, Bilodeau L

Department of Medicine, Montreal Heart Institute, Montreal University, Montreal, Quebec, Canada.

Balloon refractory calcific coronary plaques remain a technical challenge. Stent underexpansion is known as a major cause of restenosis and thrombosis. We report a case of in-stent restenosis 5 months after stent suboptimal implantation in noncompliant calcific atherosclerotic plaque which could not be disrupted by repeated prolonged high-pressure balloon inflations. High-energy excimer laser use altered underlying lesion morphology, allowing full stent apposition. Advances in equipment and technique have allowed more frequent use of high energy excimer laser technology during percutaneous coronary angioplasty with very low rates of complications. Laser technology represents a useful tool to overcome resistant lesions during percutaneous coronary interventions.

Int J Cardiol. 2008 Jun 23;127(1):98-102. Epub 2008 Feb 15Excimer laser in acute myocardial infarction: single centre experience on 66 patientsAmbrosini V, Cioppa A, Salemme L, Tesorio T, Sorropago G, Popusoi G, Stabile E, Medolla A, Cangella F, Agrusta M, Picano E, Rubino P

CNR, Institute of Clinical Physiology, Pisa, Italy; Clinica Cardiologica "Montevergine", Mercogliano, Italy. scientific1@virgilio.it

Background: Pulsed-wave ultraviolet excimer laser light at 308 nm can vaporize thrombus, suppress platelet aggregation, and, unlike other thrombectomy devices, ablates the underlying plaque.

Aim: To evaluate both safety and efficacy of laser ablation in patients presenting with Acute Myocardial Infarction (AMI) complicated by persistent thrombotic occlusion.

Methods: From May 2003 to October 2006, we enrolled 66 AMI patients (age 59+/-11 years; 57 men) presenting complete thrombotic occlusion of the infarct related vessel. All patients were treated with laser. Primary acute angiographic end-points was corrected TIMI frame count. Secondary echocardiographic end-point was left ventricular remodeling defined as an increase in end-diastolic volume >/=20% 6 months after infarction. Tertiary clinical endpoint was event-free survival at 6 months follow-up.

Results: There were no intra-procedural death or coronary perforation. One primary angiographic failure was observed during lasing. Major dissection occurred in 1 (1.5%) and distal embolization in 4 patients (6%). Corrected TIMI frame count was 100 at baseline, 29+/-0.6 after lasing and 22+/-3 after stenting. At 6-months follow-up, left ventricular remodeling occurred in 8% patients. Event-free survival was 95% at 6-months follow-up.

Conclusion: Laser angioplasty is feasible, safe and effective for the challenging treatment of patients with AMI and thrombus-laden lesions. The acute effects on coronary epicardial and myocardial reperfusion are excellent.

Kardiologiia. 2008;48(3):8-12Excimer laser coronary angioplasty in combination interventional treatment of patients with acute coronary syndromeArdashev AV, Shavarov AA, Rybachenko MS, Konev AV

NN Burdenko Central Military Hospital, Moscow, Russia

The authors present first experience of application of the system for rheolytic therapy AngioJet in a group of patients with acute myocardial infarction. They describe principle of the work of rheolytic systems, possible procedure related complications. They also discuss results of clinical studies analyzing efficacy of antithrombotic therapy, efficacy and safety of rheolytic therapy in patients with acute coronary syndrome and complicated atherosclerotic plaques in coronary arteries.

Neurosurg Focus. 2008;24(2):E6

Excimer laser-assisted nonocclusive anastomosis. An emerging technology for use in the creation of intracranial-intracranial and extracranial-intracranial cerebral bypassLanger DJ, Van Der Zwan A, Vajkoczy P, Kivipelto L, Van Doormaal TP, Tulleken CA

Albert Einstein College of Medicine and The Roosevelt Hospital, New York, NewYork 10128, USA. dlanger@chpnet.org

Excimer laser-assisted nonocclusive anastomosis (ELANA) has been developed overthe past 14 years for assistance in the creation of intracranial bypasses. TheELANA technique allows the creation of intracranial-intracranial andextracranial-intracranial bypasses without the need for temporary occlusion ofthe recipient artery, avoiding the inherent risk associated with occlusion time. In this review the authors discuss the technique and its indications, whilereviewing the clinical results of the procedure. The technique itself isexplained using cartoon drawings and intraoperative photographs. Advantages anddisadvantages of the technique are also discussed.

Lasers Med Sci. 2008 Jan;23(1):1-10. Epub 2007 Apr 11Excimer laser in myocardial infarction: a comparison between STEMI patients with established Q-wave versus patients with non-STEMI (non-Q)CARMEL Excimer Laser Interventional Study Group, Topaz O, Ebersole D, Dahm JB, Alderman EL, Madyoon H, Vora K, Baker JD, Hilton D, Das T

Patients sustaining acute myocardial infarction (AMI) often require urgent percutaneous revascularization within the first 24 h from onset of the infarction due to continuous ischemia and hemodynamic instability. Upon arrival to the cardiac catheterization, the electrocardiogram of AMI patients may exhibit acute ST-elevation (STEMI) with or without accompanying Q-wave or depression of the ST segment (non-STEMI or non-Q-wave infarction). Data comparing acute outcome of device application in patients presenting for urgent revascularization with established Q-wave myocardial infarction (QWMI) versus those with non-STEMI (NQMI) are sparse. Excimer laser is a revascularization modality applied for debulking of atherosclerotic plaque and vaporization of associated thrombus in the setting of AMI. One hundred fifty-one AMI patients with continuous chest pain and ischemia who enrolled into a multicenter study and underwent urgent revascularization were divided for the purpose of a retrospective analysis into two groups. One group presented with established electrocardiographic Q-wave, whereas the other had ST-depression (NQMI). In comparison with the NQMI group, the QWMI patients had a higher incidence of failed thrombolytic therapy (17% vs 3, p = 0.006), cardiogenic shock (20 vs 6%, p = 0.01), left anterior descending as a culprit infarct-related vessel (46 vs 14%, p < 0.0001), a higher incidence of TIMI 0 flow (48 vs 24%, p = 0.04), a heavier thrombus burden (grade 4 TIMI thrombus, 58 vs 23%; p = 0.0001), and higher CPK (1272 +/- 2180 vs 404 +/- 577, p = 0.001) and troponin levels (62 +/- 95 vs 14 +/- 48, p = 0.0003). Both groups underwent laser angioplasty and stenting for relief of continuous chest pain and ischemia within 24 h of infarction onset. Quantitative coronary arteriography in an independent core laboratory measured similar improvement in baseline minimal luminal diameter and percent diameter stenosis by application of laser energy in both groups. Among the QWMI patients, a significantly higher acute gain was recorded with the laser treatment in lesions containing a large/extensive thrombus burden as compared with lesions containing only a small clot burden (1.2 +/- 0.7 vs 0.8 +/- 0.5, p = 0.01). Such a phenomenon was not detected among the NQMI patients (1.0 +/- 0.5 vs 0.8 +/- 0.6, p=ns). Baseline TIMI flow grade (0.9 +/- 1.0 for QWMI vs 1.5 +/- 1.2 for NQMI, p = 0.0001) increased with laser emission to 2.8 +/- 0.5 and subsequently reached a final level of TIMI 3 in both groups. In comparison with the QWMI patients, there was a trend toward a reduced rate of major adverse coronary events among the NQMI patients (12% QWMI vs 4% NQMI, p = 0.09). Significant differences in baseline clinical characteristics, extent of myocardial damage, location of infarct related vessel, thrombus burden, and TIMI flow exist between QWMI and NQMI patients who require urgent intervention. However, application of excimer laser results in similar high procedural success and low complication rates in both groups. Maximal acute laser gain is achieved among QWMI patients whose lesions are laden with a heavy thrombus burden.

J Vasc Surg. 2007 Aug;46(2):289-295. Epub 2007 Jun 27Mid-term results with laser atherectomy in the treatment of infrainguinalocclusive diseaseStoner MC, deFreitas DJ, Phade SV, Parker FM, Bogey WM, Powell S

Section of Vascular and Endovascular Surgery, East Carolina University,

Greenville, NC 27834, USA. stonerm@ecu.edu

Background: Laser atherectomy offers a potential intervention for multivessel infrainguinal disease in patients with poor revascularization options. Despitepromising early results reported in the literature, the proper patient populationwho might benefit from laser atherectomy has yet to be determined.

Methods: From July 2004 to June 2006, patients undergoing laser atherectomy were retrospectively reviewed and assessed for comorbidities, operative and follow-up variables potentially associated with the end points of nondefinitive therapy,and limb salvage.

Results: During the study period, 40 patients (21 women, 19 men) underwent laser atherectomy, and the average follow-up was 461 +/- 49 days (range, 17 to 1050days). Their average age was 68 +/- 2 years (range, 43 to 93 years). Theindication for laser atherectomy was critical limb ischemia in 26 (65%) and lowerlimb claudication in 11 (35%). A total of 47 lesions were treated in thefollowing arterial segments: 34 femoropopliteal and 13 infrapopliteal.Femoropopliteal distribution by the Trans-Atlantic Society Classification (TASC) was A in 3, B in 17, C in 10, D in 4, and infrapopliteal lesions distribution wasA in 1, B in 3, C in 4, and D in 5. Adjunctive angioplasty was used in 75% ofcases. The overall technical success rate (<50% residual stenosis) was 88%. Laseratherectomy-based treatment was the definitive therapy for 23 patients (58%), andthe overall 12-month primary patency was 44%. The limb salvage rate at 12 months in 26 patients with critical limb ischemia was 55%. Renal failure was a riskfactor for amputation (P < .001) and failed primary patency (P < .05), type 2diabetes mellitus was a risk factor for amputation (P < .05), and poor tibialrunoff was associated with failed primary patency and amputation (P < .05).Outcome was associated with the number of patent infrapopliteal runoff vessels.

Conclusion: These data demonstrate that laser atherectomy can be used with highinitial technical success rate. Chronic renal failure and diabetes are riskfactors for a negative outcome. Poor results in patients with diabetes and renal failure necessitate careful case selection in this subgroup, in which laseratherectomy is less likely to provide a definitive revascularization result orlimb salvage.

J Endovasc Ther. 2007 Jun;14(3):365-73Initial experience with directed laser atherectomy using the CLiRpath photoablation atherectomy system and bias sheath in superficial femoral artery lesionsRastan A, Sixt S, Schwarzwälder U, Kerker W, Bürgelin K, Frank U, Noory E, Gremmelmeier D, Branzan D, Hauswald K, Brantner R, Schwarz T, Zeller T

Department of Angiology, Heart Centre Bad Krozingen, Germany.

Purpose: To report a safety and efficacy study of directed excimer laser atherectomy with the Bias Sheath guiding catheter to create larger lumens in the superficial femoral artery (SFA).

Methods: Fourteen patients (9 men; mean age 66+/-9 years, range 46-76) with chronic lower limb ischemia (Rutherford class 2 to 5) referable to SFA stenoses were treated with the 8-F-compatible Bias Sheath and a 1.7- or 2.0-mm laser catheter. Eight (57%) lesions were de novo and 6 (43%) were in-stent restenoses (ISR). Mean diameter stenosis was 96%+/-8% (range 80%-100%; 10 total occlusions), and mean lesion length was 126+/-78 mm (range 30-290). The primary study endpoint was laser success, defined as <50% angiographic residual stenosis post-laser, without major perforations.

Results: The primary endpoint was achieved in 8 (57%) lesions; all patients underwent additional balloon angioplasty, which achieved an angiographic residual stenosis <30% in all. Three lesions could not be completely traversed with the study device. Two dissections were detected after Bias Sheath application; 1 required stenting. There were 2 embolic events (specific to the antegrade device design); both were treated with aspiration therapy. Intravascular ultrasound (IVUS)-based minimal lumen diameters were 0.23+/-0.2 mm (range 0-1.0) at baseline and 3.2+/-0.8 mm after Bias Sheath application. Rutherford category improved at 1 month in 10 (71%) patients. One patient remained unchanged, another worsened (category 2 to 3), 1 died, and the fourth was not examined. The ankle-brachial index improved from 0.41+/-0.18 at baseline to 0.79+/-0.19 at discharge and to 0.80+/-0.19 at 1 month. Primary 1-month patency (<50% restenosis by duplex) was 85% (11/13 lesions).

Conclusion: SFA lesions, including ISR, can be treated in the majority of cases with directed laser atherectomy, significantly reducing plaque burden as measured by IVUS. Embolization was attributed to device-specific features of the prototype antegrade sheath design, which was discontinued. Larger studies are mandatory to document the long-term technical and clinical impact of this new device.

Int J Cardiol. 2007 Mar 2;116(1):20-6. Epub 2006 Aug 7Excimer laser thrombus elimination for prevention of distal embolization and no-reflow in patients with acute ST elevation myocardial infarction: results from the randomized LaserAMI studyDörr M, Vogelgesang D, Hummel A, Staudt A, Robinson DM, Felix SB, Dahm JB

Department of Internal Medicine B, Cardiology, Ernst-Moritz-Arndt University, Friedrich-Loeffler-Str. 23 a, D-17487 Greifswald, Germany, mdoerr@uni-greifswald.de

Background: Results for standard revascularization therapies in acute myocardial infarction (AMI) have been limited in part by distal embolization, a process which might be reduced by the application of ultraviolet laser light. The aim was to assess feasibility and safety of excimer laser coronary angioplasty (ELCA) in a randomized study in AMI.

Methods: Twenty-seven consecutive patients with ST-segment elevation AMI (aged 57.8+/-9.2 years) were randomized either to balloon angioplasty and stent implantation alone (n=13) or adjunct ELCA (n=14). Quantitative coronary angiography was analyzed by an independent core laboratory.

Results: ELCA was feasible and safe in all cases. No procedure-associated complications were observed. Similar results were found for main parameters in laser (L) and control (C) patients: diameter stenosis decreased from 94.3+/-9.6 to 20.7+/-10.3% (L) and from 82.7+/-16.8 to 18.9+/-5.5% (C) (p=ns; L vs. C). TIMI flow increased from 0.7+/-1.2 to 2.8+/-0.4 and from 1.7+/-1.5 to 3.0+/-0 (p=ns; L vs. C), respectively. The post-procedural myocardial blush score did not differ between the groups (2.1+/-1.3 and 2.7+/-1.0; p=ns; L vs. C) and the final corrected TIMI frame count (cTFC) was also similar in both groups (23+/-7 and 22+/-4; p=ns; L vs. C), but the cTFC gain was higher in the laser group (53+/-14% and 35+/-20%; p<0.05; L vs. C).

Conclusions: Laser angioplasty is feasible and safe for the treatment of patients with ST elevation AMI. Procedural results were at least on par with conventional treatment. Further randomized controlled trials are needed to assess the benefit of laser angioplasty in AMI.

Semin Vasc Surg. 2007 Mar;20(1):29-36Recanalization of infrainguinal vessels: silverhawk, laser, and the remote superficial femoral artery endarterectomyShafique S, Nachreiner RD, Murphy MP, Cikrit DF, Sawchuk AP, Dalsing MC

Department of Surgery, Division of Vascular Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA. sshafiqu@iupui.edu

There are multiple endovascular options to achieve percutaneous revascularization of chronic superficial femoral artery (SFA) stenoses and occlusions. Most rely on forceful displacement of plaque via balloon angioplasty, either as a stand-alone therapy or supplemented by cold thermal injury (cryoplasty), microtome assistance (cutting balloon angioplasty), nitinol stent deployment, or expanded polytetrafluoroethylene-lined nitinol stent deployment. Excellent technical success rates are routinely described in the literature. The essential problem associated with these techniques is the predictable compromise of the initial result by neointimal hyperplasia leading to poor long-term results. An alternative to forceful displacement techniques is use of directional atherectomy or excimer laser to debulk the atheromatous lesion, with the addition of low-pressure angioplasty or stent deployment as needed. Currently, directional atherectomy is performed using the Silverhawk Plaque Excision System (FoxHollow, Redwood City, CA), while laser atherectomy is frequently performed with the CLIRpath Excimer Laser (Spectranetics Corp., Colorado Springs, CO). While both techniques can be utilized for de novo atherosclerotic lesions, even eccentric lesions or ostial lesions, proponents of these devices have also shown good short-term results in the treatment of

restenoses. Remote SFA endarterectomy with the Aspire stent (Vascular Architects, San Jose, CA) is a hybrid surgical and endovascular technique that is useful for debulking plaque from the SFA with adjunctive stenting of the distal SFA. We present a review of various alternative techniques to forceful balloon dilation used in the recanalization of the SFA with potential pitfalls and complications, along with a review of literature associated with each of these techniques.

Semin Intervent Radiol. 2007 Mar;24(1):58-62Tibial recanalization with excimer laser angioplastyEcanow JS, Schwartz BT, Park R

Department of Radiology, Provena Saint Joseph Hospital, Elgin, Illinois

We report a case of chronic critical limb ischemia (CLI) due to occlusive tibial artery disease that we treated with an excimer laser with good clinical results. The current status of laser technology in the treatment of infrainguinal arterial disease is reviewed, and our approach to the use of this device in these challenging patients is presented. Data that indicate the value of this modality in the treatment of patients with CLI are discussed.Images from this publication.

Minerva Cardioangiol. 2007 Feb;55(1):73-82Acute myocardial infarction interventional procedures: primary percutaneous coronary intervention versus facilitated percutaneous coronary intervention, rescue angioplasty, rescue excimer laserRebuzzi AG, Niccoli G, Ferrante G

Department of Cardiology, Agostino Gemelli Polyclinic, Catholic University, Rome,Italy. arebuzzi@rm.unicatt.it

ST-elevation myocardial infarction is due to the occlusion of a coronary artery, mainly due to a rupture of an atherosclerotic plaque with superimposed thrombosis. The main therapeutic goal is to restore the blood flow within the culprit artery as quickly as possible. In this review we discussed the several approaches which have been employed to reach this target. Primary percutaneous coronary intervention (PCI) is considered the best treatment option, as it is associated to lower in-hospital mortality, reduced risk of reinfarction and stroke, lower rate of intracranial bleeding and ventricular rupture from myocardial hemorrhage compared with fibrinolytic therapy. Also, it is superior to facilitated PCI, i.e. immediate planned PCI after i.v. thrombolytic therapy administration, because of lower mortality, reinfarction rate, strokes and bleedings. Rescue PCI after failed thrombolysis was associated with a reduction of early severe heart failure and improved survival at 1 year, in patients with moderate to large infarctions, compared to conservative medical therapy, in a pooled analysis of 9 randomized trials, carried out in the balloon era. Also in the stent era, a meta-analysis of 5 randomized trials found a

significant 36% reduction in the risk of 30-day mortality, a trend to lower risk of heart failure, although a marginally increased risk of thromboembolic stroke, in the rescue PCI arm. However, rescue PCI is not associated with a better long-term clinical outcome. Laser thrombectomy before PCI could be a useful additional strategy which might be compared to standard stenting in future randomized studies.

J Neurosurg. 2006 Nov;105(5):758-64Expanded polytetrafluoroethylene graft for bypass surgery using the excimer laser-assisted nonocclusive anastomosis techniqueReinert M, Verweij BH, Schaffner T, Mihalache G, Schroth G, Seller RW, Tulleken CA

Department of Neurosurgery, Institute of Pathology, Inselspital Bern, University of Bern, Switzerland. michael.reinert@neurochirurgie-bern.ch

Object: Patients with complex craniocerebral pathophysiologies such as giant cerebral aneurysms, skull base tumors, and/or carotid artery occlusive disease are candidates for a revascularization procedure to augment or preserve cerebral blood flow. However, the brain is susceptible to ischemia, and therefore the excimer laser-assisted nonocclusive anastomosis (ELANA) technique has been developed to overcome temporary occlusion. Harvesting autologous vessels of reasonable quality, which is necessary for this technique, may at times be problematic or impossible due to the underlying systemic vascular disease. The use of artificial vessels is therefore an alternative graft for revascularization. Note, however, that it is unknown to what degree these grafts are subject to occlusion using the ELANA anastomosis technique. Therefore, the authors studied the ELANA technique in combination with an expanded polytetrafluoroethylene (ePTFE) graft.

Methods: The experimental surgeries involved bypassing the abdominal aorta in the rabbit. Ten rabbits were subjected to operations representing 20 ePTFE graft-ELANA end-to-side anastomoses. Intraoperative blood flow, followup angiograms, and long-term histological characteristics were assessed 75, 125, and 180 days postoperatively. Angiography results proved long-term patency of ePTFE grafts in all animals at all time points studied. Data from the histological analysis showed minimal intimal reaction at the anastomosis site up to 180 days postoperatively. Endothelialization of the ePTFE graft was progressive over time.

Conclusions: The ELANA technique in combination with the ePTFE graft seems to have favorable attributes for end-to-side anastomoses and may be suitable for bypass procedures.

Lasers Surg Med. 2006 Oct;38(9):875-9Aspirin reduces platelet aggregation during high-energy excimer laserHuang R, Patel RB, Ma H, Taylor K, Abela GS

Division of Cardiology, Department of Medicine, Michigan State, University, East Lansing, Michigan 48824, USA

Background And Objectives: Excimer laser is used clinically in arterial revascularization procedures. This study evaluated the efficacy of aspirin in reducing platelet aggregation during high-energy excimer lasing.

Study Design/Materials And Methods: Platelet rich plasma (PRP) from seven rabbits was circulated in a dual organ chamber with aspirin added to one and the other was control. PRP was irradiated using an excimer laser (308 nm; 45 mJ/mm(2); 25 Hz; 5 minutes) via a 2.0 mm laser catheter. Platelet aggregation (particle volume) was measured by laser-light scattering. Morphology was evaluated by phase contrast and electron microscopy.

Results: Baseline platelet volume was 3.4 microm(3) for both control and aspirin groups. Following lasing, platelet volume peaked at 102.2 +/- 18.5 microm(3) for control compared to 43.1 +/- 49.2 microm(3) for aspirin-treated PRP (P < 0.0001).

Conclusion: Aspirin reduces large platelet aggregates but not small aggregates by 58% during lasing of PRP.

J Endovasc Ther. 2006 Oct;13(5):603-8

Percutaneous laser-facilitated thrombectomy: an innovative, easily applied, and effective therapeutic option for recanalization of acute and subacute thrombotic hemodialysis shunt occlusionsDahm JB, Ruppert J, Doerr M, Bordihn N, Maybauer W

Department of Angiology, Clinic Neu-Bethlehem, Goöttingen, Germanydahm@herz-gefaesszentrum.org

Purpose: To report our experience with excimer laser-facilitated recanalization of acute and subacute thrombotic occlusions of hemodialysis shunts.

Methods: Twenty-one patients (16 women; mean age 54+/-19 years, range 31-76) presented with acute and subacute thrombotic occlusions of their hemodialysis shunts (4 Cimino, 17 prosthetic; 18 forearm, 3 upper arm); mean occlusion time was 4.1+/-3 days (range 1-14), and the thrombotic occlusion measured a mean 17.4+/-9 cm (range 5-27). Fresh thrombus was observed in addition to the total shunt occlusion in all cases. All patients were treated initially with a pulsed ultraviolet (308-nm) excimer laser. Eighteen (85.7%) patients received adjunctive local thrombolysis for treatment of residual thrombus. Nineteen (90.5%) patients underwent angioplasty of the underlying anastomotic stenosis.

Results: The angiographic occlusion was reduced from 100% to 63%+/-28% after laser treatment and to 36%+/-18% after 1 hour of thrombolytic therapy (20 mg tissue plasminogen activator). TIMI flow increased significantly from grade 0 to 2.7+/-0.5 following laser ablation (p<0.001) and to 3.0+/-0.2 upon completion of the angioplasty procedure (p>0.001 versus baseline). The immediate procedural success was 95.2% (20/21). Detectable thrombotic embolization and laser-related complications were not observed in any case. Primary patency was 85%; 3 patients had abnormal Doppler flow within 6 weeks and underwent reintervention (secondary patency 100%). All successfully treated shunts were usable for further dialysisat the 6-week follow-up.

Conclusion: Percutaneous excimer laser-facilitated thrombus vaporization is safe and effective for recanalization of acute and subacute thrombotic occlusions of hemodialysis shunts.

Vasc Endovascular Surg. 2006 Aug-Sep;40(4):268-74Laser atherectomy for lower extremity revascularization: An adjunctive endovascular treatment optionZhou W, Bush RL, Lin PH, Peden EK, Lumsden AB

Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, 1709 Dryden St. Suite 1500, Houston, TX 77030, USA. wzhou1@bcm.tmc.edu

Excimer laser atherectomy (LA) employs precision laser energy control (shallow tissue penetration) and safer wavelengths (ultraviolet as opposed to the infrared spectra in older laser technology), which decreases perforation and thermal injury to the treated vessels. Though extensively used by cardiologists for severe obstructive coronary artery disease, peripheral interventionalists have not accepted LA as a routine adjunctive technique for stenotic or occluded vessels. We report herein the technical and clinical outcomes with LA for complex peripheral vascular disease in patients deemed high-risk for conventional surgical revascularization. Over a 6-month period, 19 lesions in 15 high-risk patients (mean age 72 +/-10 years) were treated with LA (308-nm spectral wavelength) followed by balloon angioplasty for limb-threatening ischemia (n = 10) and severe disabling claudication (n = 5). The lesions were located at the superficial femoral artery (n = 8), popliteal artery (6), and/or tibial vessels (5). The mean occlusion length was 10.3 +/-2.3 cm. Laser catheter choice ranged from 1.4 to 2.5 mm depending on the target vessel diameter. Clinical examination, duplex ultrasound, and ankle-brachial indices were performed in follow-up visits. Immediate technical success was achieved in 16 (84%) lesions. In the 3 technical failures, inability to cross the lesion with a wire (n = 2) or vessel perforation (n = 1) precluded successful LA. Overall, primary patency as assessed by duplex was 57% (superficial femoral artery 71%, popliteal 60%, tibial vessels 25%). Clinical improvement was seen in 10 lesions (77%) that were successfully treated initially. One patient required below-knee amputation. At an average of 2-year follow-up, 6 patients who were initially successfully treated were alive (46%), including 3 patients (50%) with stable symptoms without the need for major amputation. Laser atherectomy is a useful adjunctive revascularization technique for high-risk patients with limb-threatening ischemia. This technique is especially beneficial in the treatment of ostial lesions, which may be prone to

distal embolization, as well as total occlusions that can be traversed by a guide wire but not a balloon. Vascular surgeons should add LA to their endovascular armamentarium for the treatment of complex peripheral vascular disease in the high surgical risk patients. Further study of clinical outcome measures and comparison to other interventional techniques are warranted.

EuroIntervention. 2006 Aug;2(2):265-9Small 0.7 mm diameter laser catheter for chronic total occlusions, small vesse tortuous anatomy, and balloon-resistant lesions - development and initial experience.Taylor K, Harlan K, Branan N

The Spectranetics Corporation, Colorado Springs, CO, USA

Excimer laser coronary atherectomy (ELCA) has been an FDA-approved treatment for coronary artery disease since 1992 and is commonly used as an adjunct treatment to balloon angioplasty. While ELCA presents a good therapeutic option for lesions non-dilatable or uncrossable with balloon angioplasty, historically the technique was not able to manage heavily calcified lesions. The advent of a smaller (0.9 mm tip diameter) excimer laser coronary catheter (Point 9, Spectranetics Corporation), capable of delivering higher energy densities and repetition rates, has proven effective and safe in the treatment of complex calcified lesions1-3. However, there is still a need for a smaller laser catheter for use in small vessels in other anatomical locations, balloon-resistant lesions, and for primary crossing of CTOs. We recently developed a new, even smaller over-the-wire (OTW) laser catheter (Point 7) capable of accessing the most distal vasculature and providing an additional margin of safety in treating complex lesions. Combined with a simple guidewire steering element this device could possibly be used to traverse the proximal cap of CTOs and assist in the primary crossing of the blockage.

Lasers Med Sci. 2006 Jul;21(2):74-81. Epub 2006 May 4Hyperplasia suppression by Ho:YAG laser intravascular irradiation in rabbitNakatani E, Arai T

School of Fundamental Science and Technology, Graduate School of Science andTechnology, Keio University, 3-14-1, Hiyoshi, Yokohama, 223-8522, Japan.

The proliferation of smooth muscle cells (SMCs) was suppressed in denudatedrabbit aorta by holmium-yttrium-aluminum-garnet (Ho:YAG) laser intravascularirradiation. This study was dedicated to determine the applicability of theHo:YAG laser irradiation on chronic restenosis after balloon angioplasty. Theproliferation of SMCs in denudated rabbit aortas was suppressed in vivo 6 weeksafter the laser irradiation of 20 pulses with 60 mJ per pulse. To investigate the mechanisms of this in vivo effect, the death of SMCs by the Ho:YAG laser-induced bubble collapse pressure was studied in vitro. No significant cell deathattributed to this pressure was found. We conclude that the suppression of theproliferation of SMCs in vivo might not be caused by a reduction in density ofSMCs induced by the collapse in pressure. We submit that the suppression of SMCproliferation in vivo could be caused by the bubble expansion pressure and/orheat induced by the laser irradiation.

Semin Vasc Surg. 2006 Jun;19(2):96-101Critical limb ischemia: will atherectomy and laser-directed therapy be the answer?Clair DG

Department of Vascular Surgery, Cleveland Clinic Foundation, Cleveland, OH 44195,USA. claird@ccf.org

The interventional treatment of peripheral atherosclerotic occlusive disease is increasingly becoming accepted as an appropriate initial form of therapy. Standard methods of treatment include balloon angioplasty and stent assisted angioplasty. Laser catheters and mechanical atherectomy catheters are newer tools, which can be utilized to assist in achieving and maintaining patency in these vessels. In this report, we review the efficacy, safety, and potential advantages of these ablative devices when used for the treatment of peripheralarterial occlusive disease.

J Endovasc Ther. 2006 Feb;13(1):1-11Limb salvage following laser-assisted angioplasty for critical limb ischemia: results of the LACI multicenter trialLaird JR, Zeller T, Gray BH, Scheinert D, Vranic M, Reiser C, Biamino G; LACI Investigators

Washington Hospital Center, Washington, DC 20010, USA, and Herzzentrum, Universität Leipzig, Germany. John.R.Laird@medstar.net

Purpose: To evaluate the effectiveness of laser-assisted angioplasty for patients with critical limb ischemia (CLI) who were poor candidates for surgical revascularization.

Methods: A prospective registry at 14 sites in the US and Germany enrolled 145 patients with 155 critically ischemic limbs; the patients were poor candidates for bypass surgery owing to inadequate target vessel or saphenous vein, prohibitive cardiac disease, or significant comorbidities (ASA class 4). Additional comorbid risk factors included diabetes in 66%, hypertension in 83%, previous stroke in 21%, and myocardial infarction in 23%. Endovascular treatment included guidewire traversal and excimer laser angioplasty followed by balloon angioplasty with optional stenting.

Results: Occlusions were present in 92% of limbs. A mean of 2.7+/-1.4 lesions were treated per limb; the total median treatment length was 11 cm (mean 16.2, range 0.2-123). Stents were implanted in 45% of limbs. Procedural success, defined as <50% residual stenosis in all treated lesions, was seen in 86% of limbs. At 6-month follow-up, limb salvage was achieved in 110 (92%) of 119 surviving patients or 118 (93%) 127 limbs.

Conclusion: Excimer laser-assisted angioplasty for CLI offers high technical success and limb salvage rates in patients unfit for traditional surgical revascularization.

Eur Radiol. 2006 Feb;16(2):381-90. Epub 2005 Apr 14Percutaneous laser-assisted recanalization of long chronic iliac artery occlusions: primary and mid-term resultsBalzer JO, Gastinger V, Thalhammer A, Ritter RG, Lindhoff-Last E, Schmitz-Rixen T, Vogl TJ

Department of Diagnostic and Interventional Radiology, University Clinic, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt/Main, Germanyj.o.balzer@em.uni-frankfurt.de

We report the primary and mid-term outcome of patients with long chronic iliac artery occlusions after percutaneous excimer-laser-assisted interventional recanalization. Between 2000 and 2001, 43 patients with 46 chronic occlusions of either the common iliac artery (n=27), the external iliac artery ( n=13) or both (n=3) underwent laser-assisted percutaneous transluminal angioplasty and implantation of stents. The average length of the occlusion was 57.1+/-26 mm. After laser-assisted angioplasty and implantation of a total of 60 stents, the patients were followed up for up to 4 years. Patency rates were analyzed by ankle-brachial index (ABI) measurement and duplex ultrasound. The primary technical success rate was 95.3%, with a major complication rate of 6.9%. Clinical improvement as categorized by the Rutherford guidelines could be observed in 97.6% of cases. The ABI of all patients improved from an average of 0.46+/-0.08 before intervention to 0.97+/-0.13 at the end of the follow-up period. The overall primary patency rate was 86.1%. Four reinterventions were successful (secondary patency rate 95.4%). The mid-term results of the percutaneous recanalization of iliac artery occlusions with primary and secondary patency rates of 86.1 and 95.4% are similar to those of the treatment of short stenoses.

Angiology. 2006 Jan-Feb;57(1):21-32Current role of laser angioplasty of restenotic coronary stentsBatyraliev TA, Pershukov IV, Niyazova-Karben ZA, Karaus A, Calenici O, Guler N, Eryonucu B, Temamogullari A, Ozgul S, Akgul F, Sengul H, Dogru O, Demirbas O, Timoshin IS, Gaigukov AV, Petrakova LN, Peresypko MK, Sidorenko BA; International Invasive Cardiology Research GroupSani Konukoglu Medical Center, Gaziantep, Turkey

Treatment of in-stent restenosis (ISR) with conventional percutaneous transluminal coronary angioplasty (PTCA) causes significant recurrent neointimal tissue growth in 30-85%. Therefore, laser ablation of intrastent neointimal hyperplasia before balloon dilation can be an attractive alternative. However, the long-term outcomes of such treatment have not been studied thoroughly enough. This prospective case-control study evaluated angiographic and clinical outcomes of PTCA alone and a combination of excimer laser coronary angioplasty (ELCA) and adjunct PTCA in 125 patients with ISR. ELCA was performed before balloon dilation in 67 patients, PTCA alone was performed in 58 patients. Basic demographic and clinical data were comparable in both groups. Lesions included in ELCA group were longer (17.1+/-9.9 vs 13.6+/-9.1 mm; p = 0.034), more complex (36.5% type C stenoses vs 14.3%; p = 0.006), and more frequently had reduced distal blood flow (TIMI <3: 18.9% vs 4.8%; p = 0.025) compared to lesions in the PTCA group. Immediate angiographic results of PTCA and ELCA + PTCA appeared to be comparable. PTCA alone was successful in 57 patients (98.3%), ELCA + PTCA, in 66 patients (98.5%). The rates of hospital complications were comparable (3.0% in ELCA group vs 8.6% in PTCA group). The 1-year follow-up showed that the rates of major adverse cardiac events (MACE) were comparable in the 2 groups (37.3% in ELCA group vs 46.6% in PTCA group). The rates of target vessel revascularization (TVR) within 1 year after the intervention were also similar in the 2 groups (32.8% vs 34.5%). The data mean that ELCA in patients with complex ISR is efficient and safe. Despite a higher complexity of lesions in the ELCA group, no increase in the rate of complications was registered.

Rom J Intern Med. 2005;43(3-4):223-32Current developments in interventional treatment of total terminal aorticocclusions--laser, stenting and balloon angioplasty: experience of cardiologyclinic of Târgu-MureşBenedek I, Hintea T

Clinic of Cardiology, Emergency Clinical Hospital Mureş Târgu-Mureş, Romania.ibenedek@orizont.net

The importance of interventional procedures in the complex treatment of peripheral arterial diseases is continuously increasing. In the current practice of our clinic, association of balloon angioplasty, laser angioplasty and arterial stenting in reconstruction of iliac arteries led to superior results in the latest years, these methods 11:42 PM 11:42 PM 11:42 PM being proved as an alternative to surgical interventions. In this article, we present several cases in which current indications for laser angioplasty were extended to target occlusions located in the terminal abdominal aorta.

Methods: 106 consecutive primary iliac interventions were performed on 88 patients with iliac or aortoiliac obstructive diseases, in the period September 2001 - October 2005, at the University of Medicine and Pharmacy of Târgu-Mureş, Romania, Clinic of Cardiology. Five of these patients (4 males, 1 female) presented occlusions of terminal aorta, in whom interventional treatment (peripheral transluminal angioplasty, laser angioplasty and stenting) was performed. Three cases presented total occlusion of terminal aorta, without any visualization of iliac arteries, and 2 cases presented occlusion of one aortoiliac axis, starting from terminal aorta.

Results: In all cases, complete repermeabilisation of aortoiliac axes was achieved, without complications. In all patients we recorded a significant improvement of symptomatology, and arterial Doppler showed an increase of Doppler ankle/brachial index in average from 0.4 up to 0.95. No complications have been recorded so far.

Conclusion: Extension of classical indications of interventional treatment for balloon and laser angioplasty to occlusions located in terminal aorta is possible when the procedure is performed by an experienced team. Interventional techniques, having a superior applicability in practice, good results, low complication rates, and decreasing the hospitalization times, could be applied in the future to a larger extent, targeting also aortic occlusions.

Angiology. 2005 Jul-Aug;56(4):377-84The effect of interventional treatment in acute myocardial infarction on ST resolution: a comparison of coronary angioplasty with excimer laser angioplastyIlkay E, Karaca I, Yavuzkir M, Akbulut M, Pekdemir M

Firat University, Medical School, Department of Cardiology, Elaziğ, Turkeyilkayerdogan@superonline.com

The treatment methods for acute myocardial infarction (MI) have started to change in the new millennium. Myocardial perfusion (ST-segment resolution) is the target rather than achieving TIMI-III flow in the infarct-related artery. In this study the authors compared the effect of percutaneous transluminal coronary angioplasty (PTCA) and excimer laser angioplasty (ELCA), which was accepted as one of the thrombolysis methods, on ST-segment resolution. A stent was applied after ELCA to 36 patients (4 women, 32 men; mean age 50.44 +/-9.8 years) in group I and a stent was applied after balloon angioplasty to 44 patients (5 women, 39 men; mean age 50.77 +/-12.2 years) in group II. Fisher's exact test was used in the analysis of data, and p<0.05 was accepted as significant. There was no difference between the groups with respect to symptom duration, time to angioplasty, risk factors, infarct localization, stent diameter, and length. TIMI-III flow was achieved in 33 patients (92%) in group I and in 40 patients (91%) in group II. There was no statistical difference in TIMI flow between the groups. In group I, complete ST resolution was observed in 75% (27/36) of the patients, partial resolution in 22% (8/36), and resolution was unsuccessful in 3% (1/36). In group II, complete, partial, and unsuccessful ST resolution were 41% (18/44), 45% (20/44), and 14% (6/44), respectively. The mean ST resolution was 82.78 +/-11.8% in group I and 66.36 +/-10% in group II (p=0.001). ST segment resolution, which is a good predictor of tissue perfusion, was higher with ELCA than with balloon angioplasty. These findings should be supported by large randomized studies.

Eur J Vasc Endovasc Surg. 2005 Jun;29(6):613-9Excimer laser assisted angioplasty for critical limb ischemia: results of the LACI Belgium StudyBosiers M, Peeters P, Elst FV, Vermassen F, Maleux G, Fourneau I, Massin H

Department of Vascular Surgery, AZ St Blasius, 9200 Dendermonde, Belgium.marc.bosiers@pandora.be

Background: The purpose of this study was to assess the safety and efficacy of translating into national practice methodology for infrainguinal excimer laser-assisted angioplasty, for the treatment of critical limb ischemia in poor surgical bypass candidates.

Methods: A prospective five centre Belgian registry enrolled 48 patients, who presented with 51 chronic critically ischemic limbs (Rutherford category 4, 5 or 6) and were poor candidates for bypass surgery. Treatment included crossing the occlusion or stenosis by conventional guidewire followed by excimer laser angioplasty with, or without, adjunctive balloon angioplasty or stenting. A step-by-step technique was used in cases where the guidewire could not pass the occluded site. The primary endpoint was limb salvage, at 6 months, of the treated limb.

Results: Initial treatment was successful in all 51 limbs. By 6 months there had been six deaths, six minor and four major amputations and further intervention was required in four patients. Among survivors, limb salvage rate at 6 month was 38/42 (90.5%), with freedom from critical limb ischemia in 86%.

Conclusions: This Belgian study of excimer laser assisted angioplasty, in high-risk patients who were poor candidates for surgical re-vascularisation, had a low incidence of surgical re-interventions and limb salvage rate in excess of 90%.

Cardiol Young. 2005 Feb;15(1):91-4An experience suggesting an expanded role for the excimer laser catheter in neonates with obstructive lesions in the heartWeber HS

Children's Heart Group, Penn State University Children's Hospital, Hershey, Pennsylvania 17033, USA. hweber@psu.edu

I have previously reported the successful use of the 0.9 millimetre excimer lasercatheter in 2 neonates with pulmonary valvar atresia and intact ventricularseptum. In this report, I describe the expanded role of the excimer laser in apremature infant weighing 1.8 kilograms who presented with an occluded rightpulmonary artery secondary to an organized thrombus. Successful reconstruction ofthe right pulmonary artery was performed by sequential use of lasers of 0.9, 1.4,and 2 millimetres diameter, followed by conventional balloon angioplasty. As is

now the situation in adults, laser catheter intervention should now be anintegral part of the armamentarium of the paediatric cardiac interventionalist.

Catheter Cardiovasc Interv. 2005 Jan;64(1):67-74Prevention of distal embolization and no-reflow in patients with acute myocardial infarction and total occlusion in the infarct-related vessel: a subgroup analysis of the cohort of acute revascularization in myocardial infarction with excimer laser-CARMEL multicenter studyDahm JB, Ebersole D, Das T, Madyhoon H, Vora K, Baker J, Hilton D, Topaz O

Department of Cardiology, Ernst Moritz Arndt University Greifswald, Greifswald,Germany. dahm@mail.uni-greifswald.de

To overcome the adverse complications of percutaneous coronary interventions in thrombus laden lesions (i.e., distal embolization, platelet activation, no-reflow phenomenon), mechanical removal of the thrombus or distal embolization protection devices are frequently required. Pulsed-wave ultraviolet excimer laser light at 308 nm can vaporize thrombus, suppress platelet aggregation, and, unlike other thrombectomy devices, ablate the underlying plaque. The following multicenter registry was instituted to evaluate the safety and efficacy of laser ablation in patients presenting with acute myocardial infarction (AMI) complicated by persistent thrombotic occlusions. Patients with AMI and complete thrombotic occlusion of the infarct-related vessel were included in eight participating centers. Patients with further compromising conditions (i.e., cardiogenic shock, thrombolysis failures) were also included. Primary endpoint was procedural respective laser success; secondary combined endpoints were TIMI flow and % stenosis by quantitative coronary analysis and visual assessment at 1-month follow-up. Eighty-four percent of all patients enrolled (n = 56) had a very large thrombus burden (TIMI thrombus scale > or = 3), and 49% were compromised by complex clinical presentation, i.e., cardiogenic shock (21%), degenerated saphenous vein grafts (26%), or thrombolysis failures (5%). Laser success was achieved in 89%, angiographic success in 93%, and the overall procedural success rate was 86%. The angiographic prelaser total occlusion was reduced angiographically to 58% +/- 25% after laser treatment and to 4% +/- 13% final residual stenosis after adjunctive balloon angioplasty and/or stent placement. TIMI flow increased significantly from grade 0 to 2.7 +/- 0.5 following laser ablation (P < 0.001) and 3.0 +/- 0.2 upon completion of the angioplasty procedure (P > 0.001 vs. baseline). Distal embolizations occurred in 4%, no-reflow was observed in 2%, and perforations in 0.6% of cases. Laser-associated major dissections occurred in 4% of cases, and total MACE was 13%. The safety and efficacy of excimer laser for thrombus dissolution in a cohort of high-risk patients presenting with AMI and total thrombotic occlusion in the infarct-related vessel are encouraging and should lead to further investigation.

Ann Vasc Surg. 2005 Jan;19(1):63-8Tibial angioplasty as an alternative strategy in patients with limb-threatening ischemiaClair DG, Dayal R, Faries PL, Bernheim J, Nowygrod R, Lantis JC 2nd, Beavers FP, Kent KC

Division of Vascular Surgery, New York-Presbyterian Hospital, Columbia College ofPhysicians and Surgeons and The Weill Cornell Medical School, New York, NY 10032,USA. claird@ccf.org

The purpose of this study was to assess the technical feasibility and early outcome of tibial angioplasty for a subset of patients with limb-threatening ischemia who were not candidates for bypass grafting. A retrospective analysis was conducted of 19 patients (7 male, 12 female) who underwent crural angioplasty for limb-threatening ischemia using 0.018- or 0.014 inch-based systems. Contraindications to bypass were insufficient conduit in 7 patients and severe comorbid illness in 12. Concurrent treatment of inflow lesions was performed in 12 of 20 limbs via either angioplasty alone (5) or combined with stenting (12). Outcome measures were ankle-brachial indices (ABI), relief of rest pain, and healing or healed wounds. Twenty-three vessels were treated, including 14 tibial occlusions and 9 stenoses. The average length of diseased

segment was 11 cm (range, 3-25 cm). Thirteen of 14 occlusions were treated with subintimal recanalization, the remainder with laser recanalization. Technical success was achieved in 22 of 23 treated vessels. Mean preoperative ABI was 0.53 and mean postoperative ABI was 0.85. Palpable pulses were present in 11 of 20 limbs (55%). There was one perioperative mortality (5.2%). Mean follow-up was 3 months. Three failures occurred requiring amputation (15.8%). The remaining 16 patients were improved with healing (8) or healed (4) wounds and relief of rest pain (4). These results indicate that technical success may be achieved with outflow lesion angioplasty in the majority of patients encountered. The durability of this method of therapy is unknown, and our length of follow-up is not sufficient toanswer this question. However, an attempt at angioplasty appears justified before primary amputation and before surgical bypass in those patients at high risk for intervention.

Catheter Cardiovasc Interv. 2005 Jan;64(1):12-7Percutaneous transluminal angioplasty of infrapopliteal arteries in patients with intermittent claudication: acute and one-year resultsKrankenberg H, Sorge I, Zeller T, Tübler T

Center for Cardiology and Vascular Intervention, Hamburg, Germany. krankenberg@center-for-cardiology.de

In advanced stages of infra popliteal peripheral arterial occlusive disease with critical ischemia of the lower limb, the efficacy of percutaneous transluminal angioplasty (PTA) is well established. In contrast, PTA is currently not the therapy of choice in intermittent claudication (IC). In this prospective study, patients with IC were treated percutaneously. Technical aspects and long-term results are presented. In 78 patients (61 males, or 78.2%; age, 71 +/- 11 years) with IC (Rutherford grade 2 or 3), 104 interventions were performed. At baseline, the initial/absolute walking distance (IWD/AWD) was 49 +/- 34/102 +/- 88 m; the ankle-brachial index (ABI) was 0.61 +/- 0.2 before and 0.49 +/- 0.2 after exercise. A crossover approach was used in 74% and an antegrade access in 26% of the cases. In 19 interventions (18.3%), the excimer laser technique was used, and in 26 interventions (25%) a total of 39 stents were implanted. Procedural success rate was 89.4%. IWD and AWD improved to 107 +/- 67 m and 167 +/- 74 m (P < 0.0001 vs. baseline each), respectively, and the ABI at rest and after exercise increased to 0.88 +/- 0.13 and 0.72 +/- 0.19 (P < 0.0001 vs. baseline each). Six complications occurred (5.8%). One embolic occlusion, two minor groin hematoma, one arteriovenous fistula, one compartment syndrome, and one perforation. All were treated conservatively. After 12 months, the primary patency rate was 66.3%, cumulative primary assisted patency rate was 81.9%, and secondary patency rate was 91.5%. Percutaneous revascularization of infrapopliteal arteries in patients with IC is feasible and associated with good acute clinical results and an encouraging long-term patency rate. The complication rate is low.

J Endovasc Ther. 2004 Dec;11 Suppl 2:II207-22The excimer laser: science fiction fantasy or practical tool?Biamino G

Clinical and Interventional Angiology, Heart Center Leipzig, Germanybiag@medizin.uni-leipzig.de

Nearly 20 years ago, in vitro experiments left no doubt about the fact that laser light can ablate atherosclerotic plaque. The initial enthusiastic results with the technology, particularly in coronary arteries, were followed by reports showing unacceptably high restenosis and complication rates. These poor results were due to the premature application of an underdeveloped technology, a lack of understanding of laser/tissue interaction, and the use of incorrect lasing techniques. Consequently, and without discrimination, all lasers were banned from the catheterization laboratories for nearly a decade. Technological enhancements of the excimer laser, combined with refined catheter lasing techniques, resulted in greater debulking of atherosclerotic material in long superficial femoral artery occlusions. These results triggered the application of the excimer laser technique as an atherectomy tool in more complex lesions below the knee. The multicenter Laser Atherectomy for Critical Ischemia study clearly demonstrated that the excimer laser technology resulted in limb salvage rates >90% in patients with critical limb ischemia (CLI). Furthermore, new clinical results indicate that the excimer laser is very effective in dissolving thrombotic obstructions, redirecting this technology to the coronary field. The results of the excimer laser in CLI validate the role of the cool laser in treating complex peripheral vascular disease. The results suggest a larger indication for this technology and support a more aggressive use of these interventional techniques in the

treatment of this large patient cohort. However, all lasers are not equally effective in debulking atherosclerotic material. Only the athermic process associated with the excimer laser produces a safe and effective endovascular ablation of obstructive atherosclerotic and/or thrombotic material. The appropriate and safe utilization of the equipment and lasing techniques, combined with correct indications and patient selection, will contribute to the successful application of laser-assisted atherectomy in complex peripheral and coronary artery obstructive disease. Unfortunately, little consistent scientific data has been generated to convince the interventional community of the usefulness of excimer laser ablation.

Asian Cardiovasc Thorac Ann. 2004 Dec;12(4):291-5Excimer laser coronary angioplasty in acute myocardial infarctionIlkay E, Karaca I, Akbulut M, Kiliçoğlu AE, Yavuzkir M, Arslan N

Department of Cardiology, Firat Medical School, Zübeyde Hanim Cad. 116/6 Elaziğ, Turkey ilkayerdogan@superonline.com

We evaluated the short-term results of percutaneous excimer laser angioplasty in acute myocardial infarction. Of the 18 patients studied, 2 were female and 16 male with a mean age of 56.6 +/- 12.1 years. Thrombolysis in myocardial infarction grades 0, 1, and 2 flow was observed in 10, 5, and 3 cases, respectively, prior to the procedure. The degree of stenosis was 97.9% +/- 5.1%. The lesion was crossed with a laser catheter in all cases, using a mean number of 808 +/- 384 laser pulses. Type C dissection developed in only 1 case (6%). Except for this case, distal flow was grade 3 in all the patients. Following the procedure, ST segment resolution exceeding 70% was achieved in 14 cases (78%) within the first 90 minutes. The success rate of laser ablation was 94% (17 patients). Stent implantation was performed in all the cases. In conclusion, laser angioplasty is an effective and reliable treatment for acute myocardial infarction.

Catheter Cardiovasc Interv. 2004 Sep;63(1):7-12Wireless laser-assisted angioplasty of the superficial femoral artery in patientswith critical limb ischemia who have failed conventional percutaneousrevascularizationBoccalandro F, Muench A, Sdringola S, Rosales OR

Division of Cardiology, University of Texas Medical School Houston and MemorialHermann Hospital, Houston, Texas 77030, USA

Percutaneous revascularization has become an effective treatment for patients suffering from chronic critical limb ischemia (CLI) due to chronic atherosclerotic obstructions, including total occlusions. Unlike other vascular beds, total chronic occlusions of the femoropopliteal arteries are frequently found in patients with severe claudication or CLI. As a consequence, patientswith long chronic total occlusions of the femoropopliteal arteries are generally not considered optimal candidates for percutaneous revascularization and are frequently referred for surgical revascularization. In the present study, we sought to evaluate the feasibility, safety, and outcome of a modified wireless laser ablation technique to recanalize total occlusions in patients with CLI who had failed conventional percutaneous techniques for limb salvage. Procedural success, complications, actuarial freedom of limb loss, and surgical revascularization were evaluated in 25 patients after a mean follow-up of 13 +/- 8 months. Procedural success was achieved in 21 patients (84%). Actuarial freedom from surgical revascularization or limb loss was 72%. There was one vascular perforation. No deaths or distal embolization occurred. Three patients (12%) required limb amputation during follow-up, whereas four patients (16%) had surgical revascularization in the presence of feasible vascular targets. Limb salvage was achieved in 88% of patients when laser recanalization was combined with surgical revascularization. These results suggest that the use of laser ablation is safe and facilitates angioplasty and stenting in patients with CLI that failed conventional endovascular revascularization. This technique might prevent limb loss in patients with CLI due to femoropopliteal total occlusions, particularly in patients with unsuitable anatomy for surgical revascularization.

J Cardiovasc Surg (Torino). 2004 Jun;45(3):239-48Excimer laser assisted angioplasty for the treatment of critical limb ischemiaLaird Jr JR, Reiser C, Biamino G, Zeller T

Washington Hospital Center, Washington, DC 20010, USA. john.r.laird@medstar.net

Two decades after the clinical introduction of percutaneous transluminal angioplasty (PTA), controversy still exists about the role of PTA for the treatment of occlusive disease in the femoropopliteal and infragenicular arteries. For the patient with critical limb ischemia (CLI), where diffuse disease and long occlusions are the rule, the results with PTA have not been optimal. Surgical revascularization has long been considered the gold standard for this patient population, but this procedure is associated with significant morbidity and mortality and up to 37% of patients may be poor surgical candidates. With advances in laser catheter design and refinement of recanalization techniques, improved results have been seen with laser assisted angioplasty of complex peripheral arterial disease. There has been renewed interest in excimer laser angioplasty for the treatment of patients with long total occlusions and diffuse disease who otherwise would have limited options for treatment. Excimer laser assisted angioplasty has been shown to be a successful approach to the treatment of long occlusions in the superficial femoral artery. Data from the recently completed Laser Angioplasty for Critical Limb Ischemia Phase 2 Trial (LACI) suggest that this is a viable treatment strategy for patients with CLI who are otherwise not good candidates for bypass surgery.

Catheter Cardiovasc Interv. 2004 Jun;62(2):155-61Novel use of a high-energy excimer laser catheter for calcified and comple coronary artery lesionsBilodeau L, Fretz EB, Taeymans Y, Koolen J, Taylor K, Hilton DJ

Montreal Heart Institute, Department of Medicine, Montreal, Quebec, Canada.bilodeau@icm.umontreal.ca

This study was designed to evaluate safety and effectiveness of the 0.9 mm excimer laser coronary catheter with increased laser parameters. We report a prospective trial of 100 calcified and/or balloon-resistant lesions where a new 0.9 mm excimer laser catheter was used at standard or higher energy level to facilitate angioplasty. Standard in-hospital clinical and angiographic parameters were collected and measured. Laser technical success was obtained in 87 lesions (92%), procedural success was reached in 88 lesions (93%), and clinical success in 82 lesions (86%). Increased laser parameters were used for 29 resistant lesions. This new 0.9 mm excimer laser coronary catheter using higher energy parameters seems to be safe and effective for management of calcified and nondilatable lesions.

J Invasive Cardiol. 2004 Apr;16(4):177-80Excimer laser revascularization of saphenous vein grafts in acute myocardial infarctionEbersole D, Dahm JB, Das T, Madyoon H, Vora K, Baker J, Hilton D, Alderman E, Topaz O

Watson Clinic, LLP, 1600 Lakeland Hills Blvd., Lakeland, FL, 33805 USA. debersole@pol.net

Patients who develop acute myocardial infarction due to occlusion in a saphenous vein graft (SVG) constitute a revascularization challenge. Excimer laser angioplasty may have a potential advantage in the treatment of SVGs, since its 308 nanometer wavelength is avidly absorbed by both atherosclerotic plaque and thrombus. The data presented herein support the notion that excimer laser angioplasty is a technology that has a potential role in achieving adequate revascularization outcomes in this selected, high-risk patient population.

J Am Coll Cardiol. 2004 Mar 17;43(6):936-42Meta-analysis of randomized trials of percutaneous transluminal coronary angioplasty versus atherectomy, cutting balloon atherotomy, or laser angioplastyBittl JA, Chew DP, Topol EJ, Kong DF, Califf RM

Ocala Heart Institute, Munroe Regional Medical Center, 1511 SW 1st Avenue, Ocala,Florida 34474, USA. jabittl@aol.com

Objectives: We conducted a systematic overview (meta-analysis) of randomized trials of balloon angioplasty versus coronary atherectomy, laser angioplasty, or cutting balloon atherotomy to evaluate the effects of plaque modification during percutaneous coronary intervention.

Background: Several mechanical approaches have been developed that ablate or section atheromatous plaque during percutaneous coronary interventions to optimize acute results, minimize intimal injury, and reduce complications and restenosis.

Methods: Sixteen trials (9,222 patients) constitute the randomized controlled experience with atherectomy, laser, or atherotomy versus balloon angioplasty with or without coronary stenting. Each trial tested the hypothesis that ablative therapy would result in better clinical or angiographic results than balloon dilation alone.

Results: Short-term death rates (<31 days) were not improved by the use of ablative procedures (0.3% vs. 0.4%, odds ratio [OR] 0.94 [95% confidence interval 0.46 to 1.92]), but periprocedural myocardial infarctions (4.4% vs. 2.5%, OR 1.83 [95% CI 1.43 to 2.34]) and major adverse cardiac events (5.1% vs. 3.3%, OR 1.54 [95% CI 1.25 to 1.89]) were increased. Angiographic restenosis rates (6,958 patients) were not improved with the ablative devices (38.9% vs. 37.4%, OR 1.06 [95% CI 0.97 to 1.17]). No reduction in revascularization rates (25.2% vs. 24.5%, OR 1.04 [95% CI 0.94 to 1.14]) or cumulative adverse cardiac events rates up to one year after treatment were seen with ablative devices (27.8% vs. 26.1%, OR 1.09 [95% CI 0.99 to 1.20]).

Conclusions: The combined experience from randomized trials suggests that ablative devices failed to achieve predefined clinical and angiographic outcomes. This meta-analysis does not support the hypothesis that routine ablation or sectioning of atheromatous tissue is beneficial during percutaneous coronary interventions.

Am J Cardiol. 2004 Mar 15;93(6):694-701Excimer laser angioplasty in acute myocardial infarction (the CARMEL multicenter trial)Topaz O, Ebersole D, Das T, Alderman EL, Madyoon H, Vora K, Baker JD, Hilton D, Dahm JB; CARMEL multicenter trial

Medical College of Virginia Hospitals, VCU, Richmond, Virginia 23249, USA. on.topaz@med.va.gov

Patients with acute myocardial infarction (AMI) with thrombus-laden lesions constitute a revascularization challenge. Thrombus and atherosclerotic plaque absorb laser energy; thus, we studied the safety and efficacy of excimer laser in AMI. In a multicenter trial, 151 patients with AMI underwent excimer laser angioplasty. Baseline left ventricular ejection fraction was 44 +/- 13%, and 13% of patients were in cardiogenic shock. A saphenous vein graft was the target vessel in 21%. Quantitative coronary angiography and statistical analysis were performed by independent core laboratories. A 95% device success, 97% angiographic success, and 91% overall procedural success rate were recorded. Maximal laser gain was achieved in lesions with extensive thrombus burden (p <0.03 vs small burden). Thrombolysis In Myocardial Infarction (TIMI) trial flow increased significantly by laser: 1.2 +/- 1.1 to 2.8 +/- 0.5 (p <0.001), reaching a final 3.0 +/- 0.2 (p <0.001 vs baseline). Minimal luminal diameter increased by laser from 0.5 +/- 0.5 to 1.6 +/- 0.5 mm (mean +/- SD, p <0.001), followed by 2.7 +/- 0.6 mm after stenting (p <0.001 vs baseline and vs after laser). Laser decreased target stenosis from 83 +/- 17% to 52 +/- 15% (mean +/- SD, p <0.001 vs baseline), followed by 20 +/- 16% after stenting (p <0.001 vs baseline and vs after laser). Six patients (4%) died, each presented with cardiogenic shock. Complications included perforation (0.6%), dissection (5% major, 3% minor), acute closure (0.6%), distal embolization (2%), and bleeding (3%). In a multivariant regression

model, absence of cardiogenic shock was a significant factor affecting procedural success. Thus, in the setting of AMI, gaining maximal thrombus dissolution in lesions with extensive thrombus burden, combined with a considerable increase in minimal luminal diameter and restoration of anterograde TIMI flow, support successful debulking by excimer laser. The presence of thrombus does not adversely affect procedural success; however, cardiogenic shock remains a predictor of major adverse events during hospitalization.

Acta Radiol. 2004 Feb;45(1):23-9Treatment of long superficial femoral artery occlusions with excimer laser angioplasty: long-term results after 48 monthsWissgott C, Scheinert D, Rademaker J, Werk M, Schedel H, Steinkamp HJ

Department of Radiology, Charité Campus Virchow Klinikum, Humboldt-University Berlin, Berlin, Germany. docwiss@gmx.de

Purpose : To evaluate clinical and hemodynamical long-term results after laser angioplasty of long occlusions of the superficial femoral artery (SFA).

Material and methods: In a prospective trial of 452 patients with long occlusions of the SFA, excimer percutaneous transluminal laser angioplasty (PTLA) for recanalization was applied. The average occlusion length of the SFA was 25.5 cm (range 16-38 cm). The recanalization attempt was done with the crossover technique in 398 patients, in 36 patients with the antegrade technique and in another 18 patients with the transpopliteal technique.

Results: The application of laser angioplasty demonstrated a successful recanalization of the SFA in 386/452 patients (85.5%). Recanalization with PTLA was not possible in 66 patients (14.5%). The main reason for the unsuccessful PTLAs was obstructing calcified material (n = 28) resistant to PTLA application. After a follow-up period of 48 months there was a primary, primary-assisted, and secondary patency rate of 22.3%, 40.9%, and 43.2%, respectively.

Conclusion: Laser angioplasty of long occlusions of the SFA is a feasible procedure with a low failure rate. Long-term results are promising, but additional interventions are required in most patients if a patency rate of 43.2% is to be achieved after 4 years.

Lasers Surg Med. 2004;35(5):327-35Excimer laser ablation for valvular angioplasty in pulmonary atresia and intact ventricular septumMoskowitz WB, Titus JL, Topaz O

Cardiac Catheterization Laboratories, Division of Pediatric Cardiology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, USA

Background And Objectives: The prognosis for infants with pulmonary atresia and intact ventricular septum (PA/IVS) is poor and they present a major management challenge. Mechanical penetration of the atretic pulmonary valve is an applicable option for decompression of the right ventricle and optimization of left ventricular function. The utilization of laser energy for debulking and vaporization of the atretic valve tissue is a relevant approach due to the potential for controlled, precise mode of energy distribution.

Study Design/Patients And Methods: A 4-month-old female with PA/IVS whose failure to thrive was accompanied by critical hemodynamic abnormalities received successful percutaneous pulmonary valve plate ablation by a 0.9 mm pulsed-wave ultraviolet excimer laser catheter (308 nm wavelength, fluence 50 mJ/mm(2); 30 Hz). A "step-by-step" lasing technique was applied whereby the tip of the emitting laser catheter is advanced ahead of a guide wire that serves mainly as support for positioning of that catheter.

Results: Adequate penetration of the atretic tissue enabled introduction of balloon dilations resulting in patency of the atretic valve, decompression of the right ventricle, improved right and left ventricular hemodynamics, and oxygenation. To further investigate the effect of excimer laser energy on atretic valvular tissue this laser was applied in a specimen of heart from an infant who died because of PA/IVS. Histopathologic examination of the irradiated tissue revealed no laser-induced injury to the pulmonary valve.

Conclusions: Thus, laser ablation and penetration of an atretic pulmonary valve is feasible and safe. The penetration of the atretic valve with the laser catheter enables subsequent introduction of various sizes balloon dilations. The application of available laser sources for treatment of congenital heart diseases is reviewed.

Med Sci Monit. 2003 Jul;9(7):CR335-9Photostimulation of coronary arteries with low power laser radiation: preliminaryresults for a new method in invasive cardiology therapyDerkacz A, Biały D, Protasiewicz M, Pawlik E, Abramski K, Grobelny A, Pałasz Z,Nowosad H

Invasive Cardiology Section, Department of Cardiosurgery, Medical University ofWrocław, Poland.

Background: The main problem after percutaneous coronary intervention (PCI) is restenosis affecting the site where dilatation is performed. In order to minimize its occurrence, the method of intravascular laser photostimulation (LP) with low power irradiation has been developed. The new procedure is carried out during PCI.

Material/Methods: A special setup was prepared for intravascular photostimulation with 808 nm wavelength laser diode and special diffuser, delivering the laser light into the coronary artery. The construction of the device makes it possible to irradiate the coronary artery in the place of previously performed of dilatation, in an satisfactory and programmable manner and with uniform intensity. We describe our own, unique LP procedure. Two pilot LP procedurescarried out in our clinic are described here. The patients were diagnosed before treatment and followed up three and six months after the LP procedure with non invasive tests. After six months, a control angiography was also performed.

Results: The procedures were well tolerated. In both cases the follow-up examinations showed no evidence of restenosis.

Conclusions: The new, innovative technique of intravascular low power laser photostimulation is a relatively inexpensive and easy to use treatment method. No negative side effects were observed after two procedures. The results obtained are very promising. Because the group of treated patients is still too small, the results cannot yet be subjected to statistical analysis.

Acta Cardiol. 2003 Apr;58(2):149-53Revascularization of chronic coronary artery occlusions using laser debulking followed by stent implantationBabalik E, Gürmen T, Gülbaran M, Ersanli M, Ozturk S

University of Istanbul, Institute of Cardiology, Haseki, Istanbul, Turkeyerhanbabalik@yahoo.com

Objective: Chronic total occlusions are considered unfavourable for percutaneous balloon angioplasty because of the low rate of success and the high rate ofrestenosis. Stent implantation after recanalization of chronic total occlusionshas been shown to reduce restenosis and reocclusion rates compared with balloonangioplasty in recently published randomized trials. However, it is not wellknown whether laser debulking before stent implantation would improve the benefitof stenting in chronic total occlusions.

Methods And Results: We analysed procedural and long-term clinical andangiographic follow-up results of 48 patients who underwent laser angioplastyfollowed by stent implantation for chronic total occlusions. The procedure wascompleted successfully in 46 patients (95.8%) in whom the lesion was crossed witha guidewire. We implanted 51 stents in 46 chronic total occlusions followinglaser debulking. During in-hospital follow-up 1 patient (2.1%) had Q wave, and 4 patients (8.7%) had non-Q wave myocardial infarction. Nine patients (19.5%) hadrepeat angioplasty for restenosis and one (2.1%) underwent coronary bypassoperation at 6 months follow-up. Death or Q wave myocardial infarction did notoccur during 6-month follow-up. Thirty-nine patients (85%) had angiographicfollow-up at 6 months, and stent restenosis was found in 17 (44%) patients.

Conclusion: These high rates of restenosis and target vessel revascularization in

our study suggest that laser debulking before stent implantation does not improveclinical and angiogragic outcomes in chronic total occlusions.

Am J Cardiol. 2003 Apr 1;91(7):797-802Comparison of effectiveness of excimer laser angioplasty in patients with acute coronary syndromes in those with versus those without normal left ventricular functionTopaz O, Minisi AJ, Bernardo N, Alimar R, Ereso A, Shah R

Cardiac Catheterization Laboratories, Division of Cardiology, Medical College of Virginia Hospitals, Medical College of Virginia, Virginia Commonwealth University, Richmond 23249, USA, ontopaz@aol.com

Depressed left ventricular (LV) ejection fraction (EF) adversely affects procedural outcome during percutaneous coronary revascularization. This study examined the acute results, effectiveness, and safety of excimer laser coronary angioplasty (ELCA) in patients with acute coronary ischemic syndromes whose LVEF was depressed (<40%) versus those with preserved LVEF. One hundred patients with acute coronary syndromes (51 with unstable angina and 49 with acute myocardial infarction) underwent ELCA. Twenty-five patients (group 1) (29 lesions; 72% thrombotic) had decreased LVEF (mean 28 +/- 6%) and 75 patients (group 2) (81 lesions; 60% thrombotic) had preserved LVEF (mean 53 +/- 8%). Group 1 had a higher incidence of 3-vessel disease, Q-wave acute myocardial infarction, cardiogenic shock, diabetes, and hypertension. High laser success (87% group 1 vs 93% group 2, p = NS) and procedural success (93% group 1 vs 98% group 2, p = NS) were achieved in both groups. Minimal luminal diameter in group 1 increased from 0.7 +/- 0.5 to 1.4 +/- 0.5 mm after the laser procedure and finally to 3.0 +/- 0.4 mm; in group 2, minimal luminal diameter increased from 0.7 +/- 0.4 to 1.3 +/- 0.5 mm after the procedure to a final of 3.0 +/- 0.5 mm. The laser energy vaporized 75% of thrombus burden from the target lesion in group 1 versus 79% in group 2 (p = NS). Thrombolysis In Myocardial Infarction flow in group 1 increased from 1.4 +/- 1.2 to 2.7 +/- 0.7 by laser and finally to 2.9 +/- 0.3, and in group 2 from 2.0 +/- 1.0 to 2.8 +/- 0.6 after the laser procedure to a final of 2.9 +/- 0.4. There were no deaths, emergency bypass surgeries, strokes, or acute vessel closures in either group. Thus, ELCA is a safe and feasible revascularization modality for patients with acute coronary syndromes whose LVEF is depressed. The laser energy vaporizes a large thrombus burden from the treated plaque. Angiographic intracoronary thrombus does not adversely affect device and procedural success in these select patients.

Jpn Heart J. 2003 Mar;44(2):179-86Treatment of in-stent restenosis with excimer laser coronary angioplastyKaraca I, Ilkay E, Akbulut M, Yavuzkir M

Department of Cardiology, University of Firat-Elazig, Turkey

Diffuse in-stent restenosis remains an important problem in percutane transluminal coronary angioplasty (PTCA). In this trial, we studied the early and mid-term outcomes of excimer laser coronary angioplasty (ELCA) on diffuse in-stent restenosis. ELCA was performed in 23 patients (19 males). The mean length of the lesions was 14.3 +/- 3 mm and the mean age was 58 +/- 7 years. The minimal lumen diameter (MLD) was measured by on-line quantitative coronary angiography. Before the procedure, MLD was 0.9 +/- 0.4. The Q/non-Q-wave myocardial infarction (MI), coronary artery bypass graft (CABG), PTCA, and mortality were recorded during the procedure and at 6 months follow up. The fluence of laser emission was 45 mj/m2 and the repetition rate was 25 pulses per second. Adjunctive balloon angioplasty was performed in all of the cases at a mean 7 +/- 2 atm pressure. The procedure was successfully performed in all of the cases. Type-B dissection developed, after ELCA in 1 patient (4%). Perforation, death, cerebrovascular accidents, emergency CABG, PTCA or Q/non-Q wave myocardial infarction were not observed. MLD was 0.9 +/- 0.4 mm before ELCA, 1.8 +/- 0.9 mm (P<0.05) after ELCA, and 3.1 +/- 0.7 mm after PTCA. At 6 months follow up, there were 2 (8.7%) Q-wave myocardial infarctions and 2 (8.7%) recurrent anginal pain cases. Control angiography was obtained in 20 cases (87%). Control angiography was not accepted by 3 patients. Their maximal exercise test was negative. Angiographic restenosis was observed in 6 cases (30%). The rate of target lesion revascularization (TLR) was 5 of 23 (22%) in the patients treated with ELCA. It is concluded, ELCA is a safe and efficient debulking technology for treating diffuse in-stent restenosis.

Kardiologiia. 2003;43(10):35-44

Effectiveness of excimer laser coronary angioplasty in treatment of patients with in-stent restenosisPershukov IV, Niiazova-Karben ZA, Batyraliev TA, Erĭonuchu B, Giuler N, Temamogullari A, Ozgul' S, Akgul' F, Kadayĭfchi S, Serchelik A, Dogru O, Demirbash O, Shengiul' Kh, Karaus A, Kalenich O, Preobrazhenskiĭ DV, Peresypko MK, Petrakova LN, Sidorenko BA

International Invasive Cardiology Research Group, Presidential Medical Center,Central Clinical Hospital, Moscow, Russia

In-stent restenosis (ISR), when treated with balloon angioplasty (PTCA) alone, has an angiographic recurrence rate of 30-85%. Ablating the hypertrophic neointimal tissue prior to PTCA is an attractive alternative, however late outcomes of such treatment have not been fully determined. This multicenter case control study assessed angiographic and clinical outcomes of 137 consecutive procedures in 125 patients treated for ISR with either PTCA alone (n = 58) or excimer laser assisted coronary angioplasty (ELCA, n = 67). Demographics were similar. Lesions selected for ELCA compared with those selected for \PTCA were longer (17.1+/-9.9 mm vs. 13.6+/-9.1 mm; p=0,034), more complex (ACC/AHA type C: 36,5% vs. 14,3%; p=0,006), and with reduced antegrade flow (TIMI flow < 3: 18,9% vs. 4,8%; p = 0,025). ELCA- and PTCA treated patients had similar rates of procedural success (98,5 and 98,3%, respectively, p=1,0), major clinical complications (3,0% and 8,6%; respectively, NS), major cardiac events at 1 year (37,3 and 46,6%. respectively, NS), and target lesion revascularization (32,8 and. 34,5%; respectively, NS). These data suggest that ELCA in patients with complex in-stent restenosis is as safe and effective as PTCA. Despite higher lesion complexity in ELCA-treated patients, no increase in event rates was observed.

J Lab Clin Med. 2003 Jan;141(1):50-7Laser-light scattering, a new method for continuous monitoring of plateletactivation in circulating fluidAbela GS, Huang R, Ma H, Prieto AR, Lei M, Schmaier AH, Schwartz KA, Davis JM

Division of Cardiology, Department of Medicine, Michigan State University, EastLansing 48824, USA. george.abela@ht.msu.edu

We evaluated a novel technique of laser-light scattering (LLS) to detect platelet-volume changes continuously, reflecting platelet aggregation in circulating fluid. Carotid arteries from 20 dogs were mounted in a dual perfusion chamber. Balloon angioplasty (BA) was performed and arteries perfused with platelet-rich plasma (PRP). A He-Ne laser beam was passed through cuvettes connected to tubing draining the arteries. From the angle of incidence, the average volume of aggregates was measured by the ratio of scattering light at 1 to 5 degrees' spread on the diode array of a multichannel analyzer. Platelet volume varied linearly with the scattered light ratio at 1 to 5 degrees (y = -24.2 + 27.6 x [y = particle size, microm(3); x = scattered light ratio at 1/5 degrees]). For comparison, we used an electronic particle counter (Coulter counter) to measure platelet volume. P-selectin expression was measured to confirm platelet activation. Comparing 10 uninjured and 10 BA-injured arteries, we found that platelet volume as measured with LLS increased from 21.6 +/- 4.1 to 52.1 +/- 12.5 microm (3) (P < .003); as measured with the Coulter counter, it increased from 29.9 +/- 2.4 to 62.3 +/- 7.0 microm(3) (P < .005). Six BA-injured arteries perfused with PRP and aspirin (0.2 mg/mL) were compared with six arteries treated with BA alone. The aspirin decreased platelet volume as measured with LLS from 56.2 +/- 11.8 to 40.2 +/- 12.7 microm(3) (P < .01); the Coulter counter revealed a decrease from 51.9 +/- 18.5 to 38.8 +/- 14.2 microm(3) (P < .001). Coulter counter and LLS results were correlated: r = 0.74, P < .05. The peak of P-selectin expression coincided with peak platelet volume. These data demonstrate that increases in circulating-platelet size stimulated by endovascular injury can be reliably and continuously monitored with the use of LLS.

J Endovasc Ther. 2002 Dec;9(6):882-8Percutaneous transluminal laser angioplasty versus balloon dilation for treatment of popliteal artery occlusionsSteinkamp HJ, Rademaker J, Wissgott C, Scheinert D, Werk M, Settmacher U, Felix R

Department of Radiology, Campus Virchow Klinikum, Humboldt University, Berlin, Germany. hermann.steinkamp@charite.de

Purpose : To compare the immediate results, complication rates, and long-term outcomes of percutaneous transluminal laser angioplasty (PTLA) versus balloon dilation alone in the treatment of popliteal artery occlusions.

Methods: In a prospective nonrandomized study conducted between December 1994 and June 2000, 215 symptomatic patients with unilateral popliteal occlusions were treated with either dilation alone (88 patients: 52 men; mean age 62 years, range 48-83) or PTLA (127 patients: 70 men; mean age 64 years, range 49-86) using a 308-nm excimer laser followed by dilation. The average occlusion length was 10.4 cm (range 3-14).

Results: PTLA was successful in recanalizing 105 (82.7%) arteries, while the recanalization rate for dilation alone was only 70.4% (62/88; p=0.045). After a mean follow-up of 36 months (range 6-52), the primary and secondary patency rates were 21.7% and 50.8%, respectively, in patients with PTLA and 16.3% and 35.2% in the angioplasty group (p=0.762). The complication rates associated with both techniques were similar.

Conclusions: Although initial recanalization may be better with PTLA, it does not appear to add any long-term benefit over balloon dilation alone.

J Neurosurg. 2002 Nov;97(5):1029-35Excimer laser-assisted bypass in aneurysm treatment: short-term outcomesBrilstra EH, Rinkel GJ, Klijn CJ, van der Zwan A, Algra A, Lo RT, Tulleken CA

University Department of Neurology, University of Utrecht, The Netherlands. E_Brilstra@neuro.azu.nl

Object: If clip application or coil placement for treatment of intracranial aneurysms is not feasible, the parent vessel can be occluded to induce thrombosis of the aneurysm. The Excimer laser-assisted anastomosis technique allows the construction of a high-flow bypass in patients who cannot tolerate such an occlusion. The authors assessed the complications of this procedure and clinical outcomes after the construction of high-flow bypasses in patients with intracranial aneurysms.

Methods: Data were retrospectively collected on patient and aneurysm characteristics, procedural complications, and functional outcomes in 77 patients in whom a high-flow bypass was constructed. Logistic regression analysis was used to quantify the relationships between patient and aneurysm characteristics on the one hand and outcome measures on the other. Fifty-one patients harbored a giant aneurysm, 24 patients suffered from a ruptured aneurysm, and 35 patients from an unruptured symptomatic aneurysm. In 22 patients (29%; 95% confidence interval [CI] 19-40%) a permanent deficit developed from an operative complication. At a median follow-up period of 2.5 months, 25 patients (32%; 95% CI 22-44%) were dependent or had died; in 10 of these patients (13% of all patients; 95% CI 6-23%) operative complications were the single cause of this poor outcome. Univariate analysis demonstrated that a poor clinical condition before treatment (odds ratio [OR] 4.7; 95% CI 1.7-13.3) and a history of cardiovascular disease (OR 4.1; 95% CI 1-16.2) increased the risk of poor outcome. Multivariate analysis demonstrated that only the clinical condition before treatment was significantly related to outcome (OR 4; 95% CI 1.3-11.9).

Conclusions: In patients with an intracranial aneurysm that cannot be treated by clip application or coil placement, and in whom occlusion of the parent artery cannot be tolerated, the construction of a high-flow bypass should be considered. This procedure carries a considerable risk of complications, but this should be weighed against the disabling or life-threatening effects of compression, the high risk of rupture, and the substantial chance of poor outcome after the rupture of such aneurysms.

Stroke. 2002 Oct;33(10):2451-8Excimer laser-assisted high-flow extracranial/intracranial bypass in patients with symptomatic carotid artery occlusion at high risk of recurrent cerebral ischemia: safety and long-term outcomeKlijn CJ, Kappelle LJ, van der Zwan A, van Gijn J, Tulleken CA

University Department of Neurology, University Medical Center Utrecht, and the Rudolf Magnus Institute of Neurosciences, Utrecht, The Netherlands. c.j.m.klijn@neuro.azu.nl

Background And Purpose: The goal of this study was to determine safety and long-term outcome of the excimer laser-assisted high-flow extracranial/intracranial (EC/IC) bypass in patients with symptomatic carotid artery occlusion (CAO) at high risk of recurrent stroke.

Methods: In a prospectively collected cohort of 103 patients with symptomatic CAO, 15 patients were selected for excimer laser-assisted EC/IC bypass surgery on the basis of predefined selection criteria: (1) transient or moderately disabling symptoms of focal cerebral ischemia, not symptoms of the retina only; (2) continuing symptoms after documentation of the CAO; (3) evidence of a possible hemodynamic origin of symptoms; and (4) informed consent of the patient.

Results: Eleven patients underwent the operation without complications One patient had a severely disabling stroke (Rankin grade 4) 11 days after the operation; the bypass was found occluded on reoperation. Two other patients had a moderately disabling stroke (Rankin grade 3) immediately after the operation. One patient died of myocardial infarction 1 day after surgery. Median follow-up time was 27 months. Of the 11 patients who underwent the operation without complications, 1 died 17 months after the operation of a brainstem stroke, and another patient had a new stroke ipsilateral to his CAO 10 months after the operation but without a change in Rankin grade.

Conclusions: The excimer laser-assisted high-flow EC/IC bypass operation is a potentially promising procedure in patients with symptomatic CAO and a presumably high risk of recurrent stroke, but the procedure carries a definite risk. This risk is probably related not only to the procedure itself but also to the selection of patients.

Cardiovasc Intervent Radiol. 2002 Sep-Oct;25(5):388-96. Epub 2002 Jun 4Short (1-10 cm) superficial femoral artery occlusions: results of treatment with excimer laser angioplastySteinkamp HJ, Wissgott C, Rademaker J, Scheinert D, Werk M, Settmacher U, Felix R

Department of Radiology, Charité Campus Virchow Klinikum, Humboldt UniversityBerlin, Augustenburger Platz 1, D-13353 Berlin, Germany. hermann.steinkamp@charite.de

Purpose: To evaluate the safety and long-term results after laser angioplasty of short occlusions of the superficial femoral artery (SFA).

Methods: In a prospective trial in 312 patients with short occlusions of the SFA excimer laser angioplasty for recanalization was applied. The average occlusion length of the SFA was 7.5 cm (range 1-10 cm). The recanalization attempt was done using either a cross-over technique from the contralateral femoral artery (278 patients), antegrade technique (16 patients) or transpopliteal technique (18 patients).

Results: Percutaneous transluminal laser angioplasty (PTLA) produced successful recanalization of the SFA in 286 of 312 patients (91.7%). In 26 patients (8.3%) recanalization was not possible. The reason for the unsuccessful PTLAs was obstructing calcified materialn = 8) which was resistant to laser application. In nine cases obstructing calcifications resulted in positioning of the laser catheter in subintimal tissue or perforation of the SFA. In another four patients there was an aberrant anatomy of the SFA which resulted in a direct vessel injury after advancing the laser catheter. In five patients subintimal recanalization failed. After a follow-up period of 36 months there was a primary, primary assisted and secondary patency rate of 49.2%, 76.5% and 86.3%.

Conclusion: Excimer laser angioplasty of short occlusions of the SFA is a feasible procedure with a low failure rate. Long-term results are promising but additional interventions are required in most patients to achieve a patency rate of 86.3% after 3 years. Further studies are needed to compare the clinical outcome of PTLA and PTA in short occlusions of the SFA.

Catheter Cardiovasc Interv. 2002 Jul;56(3):365-72Laser-facilitated thrombectomy: a new therapeutic option for treatment of thrombus-laden coronary lesionsDahm JB, Topaz O, Woenckhaus C, Staudt A, Möx B, Hummel A, Felix SB

Department of Cardiology, Ernst Moritz Arndt University Greifswald, Greifswald,

Germany. dahm@mail.unigreifswald.de

To overcome the adverse complications of balloon angioplasty in thrombus burden lesions (i.e., distal embolization, platelet activation, no-reflow phenomenon with persistent myocardial hypoxemia), mechanical removal of the thrombus or distal embolization protection devices is required. Pulsed ultraviolet excimer laser light at 308 nm can vaporize thrombus and suppress platelet aggregation. Clinical experience has already shown its efficacy in acute ischemic-thrombotic acute coronary syndromes. Unlike other thrombectomy devices, a 308 nm excimer laser can ablate thrombi as well as the underlying plaque, speed up thrombus clearing, and enhance thrombolytic and GP IIb/IIIa activity. It can also be employed in patients with contraindications for systemic thrombolytic agents or GP IIb/IIIa antagonists. Our report covers clinical data and technical aspects concerning three patients with acute myocardial infarction who presented with a large thrombus burden. After successful laser-transmitted vaporization of the thrombus mass in these patients, the remaining thrombus burden was evacuated, and normal antegrade coronary flow was successfully restored. This approach can be useful for selective patients with acute coronary syndromes.

Med Tekh. 2002 May-Jun;(3):45-6Laser angioplasty technologyAverin VG, Baranov GS, Rusanov VD, Chukreev FE

The authors propose a laser angioplasty technology that differs in that pulse-periodic nitric N2-laser (wavelength, approximately 337 nm; power, 0.5 W; pulse energy, 5 mJ; repetition frequency, approximately 100 Hz) is used as a source of laser radiation. The technology has an environmental purity (a working nitrogen-helium mixture) and a vast resource (approximately 10(7) pulses). A conical-profile quartz fiber (focon) that can accumulate and transmit the bulk of laser energy is employed to transmit laser light.

J Invasive Cardiol. 2002 Apr;14(4):180-6Laser angioplasty and laser-induced thrombolysis in revascularization of anomalous coronary arteriesShah R, Martin RE, Topaz O

Division of Cardiology, Medical College of Virginia/Virginia Commonwealth University, Richmond, VA 23249, USA.

Acute coronary syndromes such as unstable angina and myocardial infarction are attributed to a pathophysiologic process that involves rupture of atherosclerotic plaque and subsequent thrombosis. Percutaneous intervention of anomalous coronary arteries in patients who present with acute coronary syndromes impose unique technical challenges related to the specific anatomic course and morphology of these vessels. Selection of appropriate guiding catheter configuration, choice of supportive guidewire, and proper delivery and activation of debulking devices and stents are important steps toward achieving adequate results. Excimer laser angioplasty is a debulking technology for removal of atherosclerotic plaque and associated thrombi. To date, application of laser angioplasty in anomalous coronary arteries is unreported. We herein present clinical data and discuss technical aspects related to performance of excimer laser angioplasty in three symptomatic patients with acute coronary syndrome, two having an anomalous right coronary artery and one with an anomalous circumflex artery. The delivery of laser energy in these cases resulted in rapid thrombolysis of an occlusive thrombus, successful debulking of the underlying atherosclerotic plaque, facilitation of adjunct balloon angioplasty and stenting, and ultimately, improved clinical condition.

Cardiovasc Res. 2002 Mar;53(4):984-92Thrombostatin, a bradykinin metabolite, reduces platelet activation in a model of arterial wall injuryPrieto AR, Ma H, Huang R, Khan G, Schwartz KA, Hage-Korban EE, Schmaier AH, Davis JM, Hasan AA, Abela GS

Department of Internal Medicine, Division of Cardiology, Michigan State University, East Lansing, MI 48824, USA

Objective: Thrombin activates platelets and contributes to the occlusion of arteries following thrombolytic therapy or angioplasty. Thrombostatin (RPPGF), the angiotensin converting enzyme degradation product of bradykinin, inhibits alpha-thrombin induced platelet activation.

We hypothesized that thrombostatin prevents platelet aggregation and adhesion after balloon angioplasty (BA).

Methods: Platelet-rich plasma (PRP) was obtained from 22 Beagle dogs before sacrifice and 10% of the PRP was labeled with 111In. Carotid arteries were then removed from each dog and mounted in a dual perfusion chamber and intimal injury was performed with BA. 111In-PRP with or without thrombostatin or aspirin alone was perfused through the arteries for 60 min. During perfusion, platelet volume was measured using a Coulter counter and a laser-light scattering technique. Platelet adhesion to arteries was measured by radioactivity count.

Results: Arterial injury alone compared to non-injury increased platelet volume in the circuit by 1.4 times (x) (P<0.05) using a Coulter counter or 1.8x (P<0.05) using laser-light scattering and increased platelet adhesion by 2.3x (P<0.01). When compared to BA injury alone, the addition of thrombostatin reduced platelet volume by 1.8x (P<0.03) as measured by Coulter counter or 1.9x (P<0.01) by laser-light scattering and platelet adhesion by 4.2x (P<0.05). Compared to BA injury alone, aspirin reduced platelet volume by 1.2x (P<0.01) as assessed by Coulter counter or 1.5x (P<0.03) using laser-light scattering and platelet adhesion by 1.8x (P<0.02).

Conclusion: Thrombostatin or aspirin independently decreases evidence of platelet activation in the canine carotid artery model of BA injury.

Stroke. 2002 Feb;33(2):428-34Cerebral blood flow restoration and reperfusion injury after ultraviolet laser-facilitated middle cerebral artery recanalization in rat thrombotic strokeWatson BD, Prado R, Veloso A, Brunschwig JP, Dietrich WD

Cerebral Vascular Disease Research Center, Department of Neurology, University ofMiami School of Medicine, Fla 33101, USA. brant@stroke.med.miami.edu

Background And Purpose: A reversible model of focal thrombotic stroke was developed in the rat and examined for histological evidence of reperfusion injury after clinically relevant times of recanalization.

Methods: The distal middle cerebral artery of 28 male Sprague-Dawley rats was occluded by 562-nm laser-driven photothrombosis for 0.5, 2, and 3 hours or permanently (each n=7) and was recanalized by 355-nm UV laser irradiation. Occlusive material was examined by transmission electron microscopy. Cortical cerebral blood flow was monitored by laser-Doppler flowmetry. Brain infarcts were examined histologically at 3 days.

Results: After occlusion, cortical cerebral blood flow was reduced to 33+/-4% of baseline for all groups and was restored to 82+/-9%, 75+/-3%, and 93+/-7% of baseline for the 0.5-, 2-, and 3-hour groups, respectively, following recanalization after 29+/-8, 38+/-20, and 70+/-33 minutes of UV laser irradiation. The thrombotic occlusion contained compactly aggregated platelets but no fibrin, with length (1.2 to 1.8 mm) proportional to the ischemic period. During recanalization, microchannels containing erythrocytes and scattered leukocytes and bordered by intact disaggregated platelets infiltrated the thrombus. Infarct volumes (mm3) at 3 days were 12+/-3 for the permanent case and 8+/-4, 24+/-3, and 30+/-9 for the 0.5-, 2-, and 3-hour cases, respectively, thus demonstrating reperfusion injury histologically in the latter 2 groups. No hemorrhage was seen.

Conclusions: UV laser-facilitated dissolution of a conventionally refractory platelet thrombus provides a novel and effective method for restoring blood flow without hemorrhagic complications during thrombotic stroke. This was the first observation of histologically confirmed reperfusion injury in such a model.

AAPS PharmSci. 2002;4(4):E41Deposition of nanoparticles in the arterial vessel by porous balloon catheters: localization by confocal laser scanning microscopy and transmission electron microscopy.Westedt U, Barbu-Tudoran L, Schaper AK, Kalinowski M, Alfke H, Kissel T

Department of Pharmaceutics and Biopharmacy, Philipps-University, D-35032Marburg, Germany

Restenosis remains the major limitation of percutaneous transluminal angioplasty (PTA) and stenting in the treatment of patients with atherosclerotic disease. Catheter-based local delivery of pharmacologic agents offers a potential therapeutic approach to reducing restenosis and minimizing undesirable systemic side effects. However, the intramural retention of liquid agents is low. Therefore, to achieve a sustained and regional release of the therapeutic agent it must be encapsulated in nanoparticle carrier systems. The purpose of this study was to investigate the size dependence of the penetration of nanoparticles after local delivery into the vessel wall of the aorta abdominalis of New Zealand white rabbits. Two milliliters of a 0.025% fluorescence-labeled polystyrene nanoparticle suspension with diameters ranging from 110 to 514 nm were infused at 2 atm and at constant PTA pressure of 8 atm into the aorta abdominalis. After the infused segments were removed, the location of nanoparticles was visualized using confocal laser scanning microscopy and transmission electron microscopy. The study demonstrates a size-dependent nanoparticle penetration into the intact vessel wall. While nanoparticles of about 100 and 200 nm were deposited in the inner regions of the vessel wall, 514-nm nanoparticles accumulated primarily at the luminal surface of the aorta. The observations confirm that size plays a critical role in the distribution of particles in the arterial vessel wall. It is additionally influenced by the formation of pressure-induced infusion channels, as well as by the existence of anatomic barriers, such as plaques, at the luminalsurface of the aorta or the connective elastic tissue.

Am J Cardiovasc Drugs. 2002;2(3):197-207Laser coronary angioplasty: history, present and futureKöster R, Kähler J, Brockhoff C, Münzel T, Meinertz T

Department of Cardiology, University Hospital Eppendorf, Medical Clinic, Hamburg,Germany. rkoester@uni-hamburg.de

The efficacy of percutaneous transluminal coronary angioplasty (PTCA) is limited by remaining plaque tissue and the development of restenosis. It has been demonstrated that the restenosis rate is low if a large lumen diameter is achieved after coronary intervention. Debulking of coronary stenoses is a concept to increase the luminal diameter after intervention. Laser angioplasty debulks coronary stenoses by ablation of atherosclerotic plaque. Since the first intravascular laser intervention, the technique has been significantly improved by the use of optimized wavelength, the development of flexible optimally spaced multifiber catheters and an additional saline flush technique. These technical advancements allowed a reduction in the incidence of adverse events, such as the number of dissections and perforations, associated with the use of the laser technique. Coronary laser angioplasty is commonly combined with adjunctive balloon angioplasty to optimize the outcome. Laser coronary angioplasty was not followed by a lower restenosis rate compared with plain balloon angioplasty in lesions without stents, however, a randomized comparison of the techniques including the use of the saline flush technique is not available yet. The value of excimer (acronym for excited dimer) laser coronary angioplasty for treatment of in-stent restenosis is still under investigation. So far, nonrandomized single center studies have not suggested a relevant benefit for this technique used for in-stent restenosis. In nonstented lesions there remain niche indications for laser angioplasty such as the treatment of ostial lesions, diffuse lesions or lesions traversable with a guidewire but not with an angioplasty balloon. Laser coronary angioplasty may also be useful after a failed balloon angioplasty and in patients with chronic total occlusions. The potential advantages of combining laser coronary angioplasty with vaporization of thrombus in patients with acute coronary syndromes are currently under evaluation.

Circulation. 2001 Oct 9;104(15):1850-5Effect of short pulsed nonablative infrared laser irradiation on vascular cells in vitro and neointimal hyperplasia in a rabbit balloon injury model.Kipshidze N, Nikolaychik V, Muckerheidi M, Keelan MH, Chekaov V, Maternowski M, Chawla P, Hernandez I, Iyer S, Dangas G, Sahota H, Leon MB, Roubin G, Moses JW

Lenox Hill Heart and Vascular Institute of New York and Cardiovascular ResearchFoundation, New York, NY, USA. nkipshidze@lenoxhill.net

Background: Neointimal hyperplasia after PTCA is an important component of restenosis.

Methods And Results: Cultures of rabbit endothelial cells and smooth muscle cells (SMCs) were irradiated with different doses of nonablative infrared (1064-nm) radiation. Normalized viability index detected with nondestructive Alamar Blue assay and direct cell count were

studied. Our experiments demonstrated dose-dependent cytostatic or cytotoxic effects of laser irradiation. We also evaluated the long-term effect of endoluminal nonablative infrared laser irradiation on neointimal hyperplasia in a rabbit balloon injury model. PTCA of both iliac arteries of 23 New Zealand White rabbits was performed. One iliac artery was subjected to intra-arterial subablative infrared irradiation via a diffuse tip fiber. The contralateral vessel served as control. The diet was supplemented with 0.25% cholesterol and 2% peanut oil for 10 days before and 60 days after PTCA. Morphometry after 60 days showed that intimal areas were 0.76+/-0.18 and 1.85+/-0.30 mm(2) in the laser and control arteries, respectively(P=2.2x10(-11)).

Conclusions: We conclude that nonablative infrared laser inhibited neointimal hyperplasia after PTCA in cholesterol-fed rabbits for up to 60 days.

J Am Coll Cardiol. 2001 Oct;38(4):1033-9Variability of myocardial perfusion defects assessed by thallium-201 scintigraphyin patients with coronary artery disease not amenable to angioplasty or bypass surgeryBurkhoff D, Jones JW, Becker LC

Department of Medicine, Columbia University, New York City, New York 10032, USA. db59@columbia.edu

Objectives: We sought to assess the variability of results obtained with thalliumscintigraphy as a method for tracking the extent of myocardial ischemia inmedically refractory patients with angina who are not suitable for coronaryartery bypass graft surgery or percutaneous transluminal coronary angioplasty.

Background: New therapies are being evaluated for patients with "no option" angina in whom medical therapy has failed. Nuclear techniques, like thallium scintigraphy, are used in multicenter trials to evaluate whether such therapies improve myocardial perfusion. However, the variability of test results is unknown in this patient group in a multicenter study.

Methods: The Angina Treatments: Lasers And Normal Therapies In Comparison (ATLANTIC) study was a randomized trial of transmyocardial laser revascularization (n = 182). Patients underwent dipyridamole thallium stress tests at baseline and 3, 6 and 12 months after enrollment. The control group (n = 90) was treated with constant medical therapy during the study and is a relevant group to investigate test variability. Test variability over time was quantified by the mean absolute change in the percentage of reversible perfusion defects between baseline and follow-up.

Results: Baseline percent myocardium with ischemia averaged 17.0 +/- 13.7% and did not change during follow-up. However, variations in the percent myocardium with reversible perfusion defects over time amounted to an average of 6 to 8 percentage points, or 43% to 55% of the baseline value. Only approximately 13% of this variability was attributable to variability in image reconstruction and analysis.

Conclusions: As demonstrated in the ATLANTIC study, percent myocardial ischemia in control subjects receiving constant medical therapy varied in individual patients by an average of approximately 50%. This may limit the utility of thallium scintigraphy to detect improved myocardial perfusion over time in response to therapy.

Cardiovasc Pathol. 2001 Sep-Oct;10(5):223-8In vivo effect of coronary laser angioplasty on atherosclerotic plaques: histopathologic analysisTopaz O, Minisi AJ, Mohanty L, Bailey N, Titus JL

Division of Cardiology, McGuire VA Medical Center, Medical College of VirginiaHospital, Virginia Commonwealth University, 1201 Broad Rock Boulevard, Richmond, VA 23249, USA. ontopaz@aol.com

Information from histopathologic examination of coronary arterial atherosclerotic plaques treated with in vivo laser energy is sparse. Directional atherectomy provides biopsies for study of tissue changes (injury) due to coronary arterial debulking devices, including laser. Sixteen patients who presented with acute ischemic coronary syndromes underwent debulking of a total of 17 obstructive intracoronary lesions with pulsed-wave holmium:YAG laser (2.1 microm

wavelength). Laser was performed with the "pulse and retreat" technique which incorporates slow catheter advancement (0.5-1 mm/s) with controlled emission of energy. Immediately postlasing, directional atherectomy was utilized to obtain irradiated plaque tissue for pathologic examination. Extent of laser-induced tissue injury to plaques was graded as 0 (no tissue damage), 1 (small foci or charring and vacuoles), 2 (large amount of charring, edge disruption and vacuoles) and 3 (extensive tissue damage). Angiographically and clinically, all 17 lesions were successfully debulked with the laser energy (mean 47+/-25 pulses), with a reduction of target lesion percent diameter stenosis from 92+/-6% to 47+/-25%. Adjunct balloon dilations further reduced the target lesions to a final of 10+/-10% stenosis. The histopathologic examination of the lased specimens demonstrated that 13 lesions (76%) had no evidence of laser-induced injury (Grade 0). Four lesions had low-level injury (Grade 1), and none had evidence of Grade 2 or 3 laser-induced trauma. Therefore, a laser debulking technique, which incorporates slow catheter advancement with controlled emission of pulses, does not cause significant injurious effects to the irradiated plaque.

J Interv Cardiol. 2001 Aug;14(4):433-7Initial experience with a low profile, high energy excimer laser catheter for heavily calcified coronary lesion debulking: parameters and results of first seven human case experiencesFretz EB, Smith P, Hilton JD

Victoria Heart Institute Foundation, 315-1900 Richmond Ave., Victoria, BritishColumbia, V8R 4R2

Background: Excimer laser coronary angioplasty (ELCA) has not been used in the setting of highly calcified, tight stenoses because the energies required to use existing catheters would lead to excessive heat damage and dissection. There are, however, cases that frequently benefit from debulking prior to percutaneous intervention. A new, small laser catheter capable of high energies and repetition was previously examined in vitro. This study describes the first in vivo use.

Purpose: To determine the safety and feasibility of a new, low profile, high energy laser catheter for creating a pilot hole to facilitate coronary angioplasty and stenting in patients with heavily calcified and occluded coronary arteries where a balloon has either failed to pass or was predicted to perform poorly. These patients represent the first patients treated with this new catheter.

Methods: At a high volume center, seven consecutive patients with anatomy as summarized above were treated and studied with QCA and then followed for 30 days post procedure for complications and Canadian Cardiovascular Society (CCS) angina class.

Results: The laser catheter crossed five out of seven lesions and partially penetrated the remaining lesions. The mean maximum luminal diameter (MLD) postlasing was 1.0 mm with Thrombolysis in Myocardial Infarction (TIMI) 3 flow. It was possible to easily balloon and stent after the pilot hole creation in all but one patient. TIMI 3 was achieved for the final result after adjunct therapy in all patients. All patients except one, who died at 3 months postprocedure ofstroke, were improved by an average of two angina classes. No late procedural-related complications developed.

Conclusions: The new, low profile laser catheter is easy to use and achieved goodresults in cases where a balloon either failed to pass or was predicted to givepoor results. Further trials are warranted for this niche technology.

Cardiovasc Radiat Med. 2001 Jul-Sep;2(3):191-6Excimer laser coronary angioplasty and intracoronary radiation for in-stent restenosis: six-month angiographic and clinical outcomesAjani AE, Waksman R, Kim HS, Satler LF, Pichard AD, Kent KM, Porrazzo M, White RL, Pinnow EE, Lindsay JR

Catheterization Laboratories, Washington Hospital Center, Suite 4B-1, 110 Irving Street Northwest, Washington, DC 20010, USA

Background: The purpose of this study was to evaluate 6-month clinical and angiographic outcomes in patients treated with excimer laser coronary angioplasty (ELCA) and intracoronary radiation (ICR) for in-stent restenosis (ISR).

Methods: A consecutive series of 175 patients with ISR treated with ELCA+ICR (gamma and beta emitters) were compared to 33 patients with ISR treated with ELCA alone. Baseline characteristics were similar between groups. ELCA+ICR and ELCA-alone patients had similar lesion lengths (25.0+/-12.0 vs. 24.0+/-16.8 mm, P=NS) in predominantly saphenous vein grafts (SVG, 38% vs. 42%, P=NS).

Results: Procedural success was high (ELCA+ICR, 97.0% vs. ELCA alone, 98.5%, P=NS), with no perforations or acute vessel closures. ELCA+ICR therapy reduced target vessel revascularization (TVR; 27% vs. 64%, P<.0001) and major adverse cardiac events [MACE: death, myocardial infarction (MI), or TVR; 30% vs. 64%, P<.0001] compared to ELCA alone. Late loss was 0.66+/-0.90 mm in ELCA+ICR patients and 0.85+/-0.60 mm in ELCA-alone patients (P=NS). Angiographic binary restenosis (>50%) was significantly reduced with adjunctive ICR (28% vs. 54%, P=.014).

CONCLUSION: Radiation therapy with ELCA significantly reduces angiographic binary restenosis at 6 months in patients with diffuse ISR, driven predominantly by reduced percutaneous TVR.

Am J Med. 2001 Jun 15;110(9):708-15stent-supported recanalization of chronic iliac artery occlusionsScheinert D, Schröder M, Ludwig J, Bräunlich S, Möckel M, Flachskampf FA, Balzer JO, Biamino G

Department of Medicine II, University of Erlangen-Nürnberg, Erlangen, Germany.

Purpose: Iliac artery occlusions that are more than a few centimeters in length are normally treated with surgical bypass grafting. The aim of this study was to evaluate the results of primary stent implantation after Excimer laser-assisted recanalization of iliac artery occlusions.subjects and methods: We studied 212 consecutive patients with chronic unilateral iliac artery occlusions (mean [+/- SD] length 8.9 +/- 3.9 cm) who were treated with Excimer laser assisted recanalization and stent implantation. Based on the criteria of the Society of Cardiovascular and Interventional Radiology, lesions were graded as class III occlusions (<5 cm) in 46 patients and as class IV (> or =5 cm) in 166 patients. A total of 527 stents (Palmaz stent, 346; Wallstent, 94; Strecker stent, 38; covered stents, 49) were implanted.

Results: Technical success was achieved in 190 (90%) patients. There was a clinical improvement of three grades in 112 (53%) patients and of two grades in 67 (32%) patients. The rate of major complications was 1.4%, which included arterial rupture (1) and embolic events (2). Primary patency rates were 84% at 1 year, 81% at 2 years, 78% at 3 years, and 76% at 4 years. Secondary patency rates were 88% at 1 year, 88% at 2 years, 86% at 3 years, and 85% at 4 years.

Conclusion: Stent-supported angioplasty is an effective treatment for iliac artery occlusions, with less morbidity and mortality than is associated with surgery. However, reported long-term patency rates after bypass surgery are greater than those we observed with interventional treatment. The value of primary stenting as compared with angioplasty alone should be evaluated in a randomized trial.

J Invasive Cardiol. 2001 May;13(5):401-5"Wireless" laser recanalization of chronic total coronary occlusionsPerin EC, Sarmento-Leite R, Silva GV, Rogers MD, Topaz O

Southwest Cardiovascular Consultants, Texas Heart Institute, 6624 Fannin, Suite 2220, Houston, TX 77030, USA.

Chronic total occlusions in particular, completely obstructed aorto-ostial lesions are among the most challenging targets in interventional cardiology. Excimer laser is a debulking technology for revascularization of complex lesions. Treatment of total occlusions with laser angioplasty can be applied providing that a guidewire traverses the entire length of the occlusion prior to device activation. In many patients with total occlusions, a guidewire is unable to penetrate the target stenosis. This communication presents a new technique termed "wireless" laser

recanalization. This approach entails recanalization of a total occlusion with a laser catheter without a leading guidewire.

J Endovasc Ther. 2001 Apr;8(2):156-66Excimer laser-assisted recanalization of long, chronic superficial femoral artery occlusionsScheinert D, Laird JR Jr, Schröder M, Steinkamp H, Balzer JO, Biamino G

Department of Medicine II, University of Erlangen-Nürnberg, Erlangen, Germanydierk.scheinert@gmx.de

Purpose: To examine the safety and efficacy of excimer laser-assisted angioplasty (ELA) for recanalization of superficial femoral artery (SFA) occlusions.

Methods: Data were analyzed from 318 consecutive patients (207 men; mean age 64.2 +/- 10.7 years, range 33-91) who underwent ELA of 411 SFAs with chronic occlusions averaging 19.4 +/- 6.0 cm in length. More than 75% of patients had severe claudication (category 3). Critical lower limb ischemia with rest pain or minor tissue loss was present in 6 and 15 patients, respectively. The mean ankle brachial index (ABI) before and after exercise was 0.62 +/- 0.15 and 0.40 +/- 0.18, respectively.

Results: The initial attempt (crossover approach 89.7%, antegrade 6.6%, transpopliteal 3.6%) to cross the occlusion with an excimer laser catheter was successful in 342 (83.2%) of 411 limbs. A secondary attempt performed in 44 of 69 failed cases was successful in 30 limbs, increasing the technical success rate to 90.5% (372/411). Complications included acute reocclusion (4, 1.0%), perforation (9, 2.2%), and distal thrombosis/embolization (16, 3.9%). Postprocedurally, 219 (68.8%) patients were asymptomatic; mild (category 1) or moderate (category 2) claudication remained in 53 (16.6%) and 26 (8.2%) patients, respectively. The primary patency at 1 year was 33.6%. In the majority of patients, reocclusion was treatable on an outpatient basis. The 1-year assisted primary and secondary patency rates were 65.1% and 75.9%, respectively.

Conclusions: Long SFA occlusions can be recanalized safely and successfully by ELA. However, to maintain patency and quality of life, intensive surveillance using objective testing followed by prompt repeat intervention are mandatory.

Am J Cardiol. 2001 Apr 1;87(7):849-55Effectiveness of excimer laser coronary angioplasty in acute myocardial infarction or in unstable angina pectorisTopaz O, Bernardo NL, Shah R, McQueen RH, Desai P, Janin Y, Lansky AJ, Carr ME

Division of Cardiology, Medical College of Virginia Hospitals, VirginiaCommonwealth University, Richmond, Virginia, USA. ONTOPAZ@aol.com

This study was conducted to evaluate the feasibility, safety, and acute results of percutaneous excimer laser coronary angioplasty (ELCA) in acute coronary syndromes. Fifty-nine patients were treated with ELCA (308 nm), including 33 patients with unstable angina pectoris (UAP) (35 vessels with 39 lesions) and 26 patients with acute myocardial infarction (AMI) (26 vessels with 29 lesions). In each patient the target lesion had a complex morphology. Overall, 71% of the patients had contraindications for pharmacologic thrombolytic agents or glycoprotein IIb/IIIa receptor antagonists. All patients received adjunct balloon dilation followed by stent implantation in 88% of patients with AMI versus 76% of patients with UAP (p = NS). Quantitative angiography was performed at an independent core laboratory; 86% laser success and 100% procedural success was achieved in the AMI group versus 87% laser success and 97% procedural success in the UAP group (p = NS). In the AMI group, the minimal luminal diameter increased from 0.77 +/- 0.56 to 1.44 +/- 0.47 mm after lasing to a final 2.65 +/- 0.47 mm versus 0.77 +/- 0.38 to 1.35 +/- 0.4 mm after lasing to 2.66 +/- 0.5 mm final in the UAP group. A prelaser percent stenosis of 76 +/- 17% for the AMI group versus 70 +/- 16% for the UAP group (p = NS) was decreased after lasing to 52 +/- 16% for the AMI group versus 51 +/- 14% for the UAP group (p = NS) and to a final stenosis of 15 +/- 17% for the AMI group versus 12 +/- 15% for the UAP group (p = NS). A 96% laser-induced reduction of thrombus burden

area was achieved in the AMI group versus 97% in the UAP group (p = NS). Preprocedure Thrombolysis In Myocardial Infarction flow of 1.3 +/- 0.9 in the AMI group versus 2.3 +/- 1.2 for the UAP group (p = 0.01) increased to a final flow of 3.0 +/- 0 for the AMI group versus 3.0 +/- 0 for the UAP group (p = NS). There were no deaths, cerebrovascular accident, emergency bypass surgery, acute closure, major perforation or major dissection, distal embolization, or bleeding complications in either group. One patient with AMI had localized perforation (caused by guidewire) without sequelae and 1 patient with UAP had an abnormal increase in creatine kinase levels. All 59 patients survived the laser procedure, improved clinically, and were discharged. Thus, early experience in patients with acute coronary syndromes suggest that percutaneous ELCA is feasible and safe.

Cardiovasc Res. 2001 Feb 1;49(2):449-55Photoangioplasty with local motexafin lutetium delivery reduces macrophages in a rabbit post-balloon injury modelHayase M, Woodbum KW, Perlroth J, Miller RA, Baumgardner W, Yock PG, Yeung A

Division of Cardiovascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA

objective: Motexafin lutetium (Lu-Tex, Antrin Injection) is a photosensitizer that selectively accumulates in atheromatous plaque where it can be activated by far-red light. The localization and retention of intra-arterially administered Lu-Tex and its efficacy following activation by endovascularly delivered light (photoangioplasty) was evaluated.

Methods: Bilateral iliac artery lesions were induced in 17 rabbits by balloon denudation, followed by a high cholesterol diet. Lu-Tex distribution within the atheroma was examined (n=8) following local injection. Fluorescence spectral imaging and chemical extraction techniques were used to measure Lu-Tex levels within the atheroma and adjacent normal tissue. Photoactivation was performed 15 min following Lu-Tex administration (180 J/cm fiber at 200 mW/cm fiber). Two weeks post photoangioplasty, vessels were harvested and hematoxylin and eosin (H&E) and RAM11 (macrophages) staining was performed.

Results: Local delivery of Lu-Tex achieved immediate high concentrations within plaque (mean 40x control iliac atheroma). Mean percent plaque area in the treated segments was significantly lower than in the non-treated contralateral lesions (73 vs. 82%, P<0.01). No medial damage was observed. Quantitative analysis using RAM11 positive cells revealed significant reduction of macrophages in treated lesions in both the intima (5 vs. 22%, P<0.01) and in media (8 vs. 23%, P<0.01) compared to untreated contralateral segments.

Conclusions: Local delivery provides high levels of Lu-Tex selectively within atheroma. Photoactivation results in a significant decrease in macrophage and a small decrease in atheroma burden without damage to the normal vessel wall.

J Clin Laser Med Surg. 2001 Feb;19(1):9-14"Optimally spaced" excimer laser coronary catheters: performance analysisTopaz O, Lippincott R, Bellendir J, Taylor K, Reiser C

Division of Cardiology, Medical College of Virginia Hospitals, Medical College of Virginia/Virginia Commonwealth U niversity, Richmond, USA.

Excimer laser angioplasty is a percutaneous treatment modality for management of selected patients with severe obstructive coronary artery disease. This technology entails application of multifiber catheters that vaporize intra-arterial plaque and thrombus with the 308-nm wavelength light. A coronary laser catheter ("OS") with increased space between its optic fibers (90 microns) at the tip was recently developed. The previous design used a closely packed fiber bundle ("CP") with a smaller space between the fibers (77 microns). We sought to determine the ablation characteristics of the new, OS design.

Methods: Experiments testing the new catheter and comparing it to the existing catheter included: (1) measurement of the laser output beam sizes and divergences; (2) evaluation of particulate matter generation during ablation of atherosclerotic tissue; (3) measurement of ablation hole sizes and tissue penetration rates; (4) histopathologic examination of laser-induced in vivo vessel wall injury.

Results: The new OS catheters produce a wider beam with higher divergence than the traditional CP catheters (6.7 degrees vs. 4.7 degrees, respectively). Testing two different levels of energy revealed the generation of a reduced number of particulate matter and shallower penetration depth with the OS catheter compared with traditional CP catheters. The OS catheters created a larger diameter of ablated hole than the CP catheters (for 2.0-mm catheters: 2.7 mm2 vs. 1.5 mm2, respectively, p = 0.01). Lasing with the OS catheters with slow advancement rates (0.2-0.5 mm/sec) resulted in creation of significantly larger-diameter holes than those produced at higher speeds (1-3 mm/sec). The in vivo vessel wall injury scores were similar among the two types of catheters tested.

Conclusions: A new design of spaced optical fibers for coronary laser catheters provides increased tissue ablation in comparison to the traditional closely packed fibers catheter. Slow advancement rates during lasing with the new OS catheter are crucial for achievement of adequate plaque debulking.

Catheter Cardiovasc Interv. 2001 Jan;52(1):24-34Clinical and angiographic outcome in the laser angioplasty for restenotic stents (LARS) multicenter registry.Giri S, Ito S, Lansky AJ, Mehran R, Margolis J, Gilmore P, Garratt KN, Cummins F, Moses J, Rentrop P, Oesterle S, Power J, Kent KM, Satler LF, Pichard AD, Wu H, Greenberg A, Bucher TA, Kerker W, Abizaid AS, Saucedo J, Leon MB, Popma JJ

Division of Cardiology, Brigham and Women's Hospital, Boston, Massachusetts02215, USA

In-stent restenosis (ISR), when treated with balloon angioplasty (PTCA) alone, has an angiographic recurrence rate of 30%-85%. Ablating the hypertrophic neointimal tissue prior to PTCA is an attractive alternative, yet the late outcomes of such treatment have not been fully determined. This multicenter case control study assessed the angiographic and clinical outcomes of 157 consecutive procedures in 146 patients with ISR at nine institutions treated with either PTCA alone (n = 64) or excimer laser assisted coronary angioplasty (ELCA, n = 93)) for ISR. Demographics were similar except more unstable angina at presentation in ELCA-treated patients (74.5% vs. 63.5%; P = 0.141). Lesions selected for ELCA were longer (16.8 +/- 11.2 mm vs. 11.2 +/- 8.6 mm; P < 0.001), more complex (ACC/AHA type C: 35.1% vs. 13.6%; P < 0.001), and with compromised antegrade flow (TIMI flow < 3: 18.9% vs. 4.5%; P = 0.008) compared to PTCA-treated patients. ELCA-treated patients had similar rate of procedural success [93 (98.9% vs. 62 (98.4%); P = 1.0] and major clinical complications [1 (1.1%) vs. 1 (1.6%); P = 1.0]. At 30 days, repeat target site coronary intervention was lower in ELCA-treated patients (1.1% vs. 6.4% in PTCA-treated patients; P = 0.158), but not significantly so. At 1 year, ELCA-treated patients had similar rate of major cardiac events (39.1% vs. 45.2%; P = 0.456) and target lesion revascularization (30.0% vs. 32.3%; P = 0.646). These data suggest that ELCA in patients with complex in-stent restenosis is as safe and effective as balloon angioplasty alone. Despite higher lesion complexity in ELCA-treated patients, no increase in event rates was observed. Future studies should evaluate the relative benefit of ELCA over PTCA alone for the prevention of symptom recurrence specifically in patients with complex in-stent restenosis.

Acta Neurochir (Wien). 2001;143(7):647-54Flow quantification of the non-occlusive excimer laser-assisted EC-IC bypass.van der Zwan A, Tulleken CA, Hillen B

Department of Neurosurgery, University Hospital of Utrecht, The Netherlands

Background: for six years, we used the excimer laser-assisted nonocclusive anastomosis technique for high-flow revascularization of the brain in patients with either nonclippable and noncoilable giant aneurysms of the internal carotid or basilar artery or progressive stroke associated with occlusive disease of the internal carotid artery. the aim of this study is to assess the blood flow capacity of this type of extra-intracranial bypass and its haemodynamic behaviour over time.

Methods: Twenty-six patients with a giant aneurysms and 8 patients with occlusive disease of the internal carotid artery were treated with the nonocclusive Excimer laser assisted EC-IC bypass. intra-operatively, direct measurements of flow in the EC-IC bypass were performed in all patients (Transonic Systems, Inc., Ithaca. NY). Postoperatively, follow up measurements of flow were performed with MR angiography in 14 patients with a giant aneurysm after occluding the internal carotid artery, and 7 patients with occlusive carotid disease.

Results: The mean flow in the laser assisted bypasses in the group of patients with a giant aneurysm was 158 ml/min after ligation or balloon occlusion of the ICA. The mean flow of the laser assisted bypass in the group of patients with ICA occlusive disease was 130 ml/min. A comparison with data on flow capacity of conventional EC IC bypasses is made. A demonstrated increase of flow in the bypass during follow up is discussed from a haemodynamic point of view.

Conclusions: The results of this study demonstrate that the flow capacity of the non occluding excimer laser assisted bypass is much higher than the capacity of the conventional, more peripherally located conventional EC IC bypass, and should therefore be denoted as High-Flow EC IC bypass. Consequently, this type of bypass can be a powerful and safe tool in new revascularization strategies.

Eur Radiol. 2001;11(8):1364-70Excimer laser-assisted recanalisation of femoral arterial stenosis or occlusion caused by the use of Angio-SealSteinkamp HJ, Werk M, Beck A, Teichgräber U, Haufe M, Felix R

Department of Radiology, Charité Campus Virchow-Klinikum, Humboldt University Berlin, Germany. hermann.steinkamp@charite.de

The aim of this study was to demonstrate the effect of excimer laser and balloon angioplasty of femoral artery stenosis and occlusion after use of a haemostatic puncture closure device. A haemostatic puncture closure device (Angio-Seal) was used in 6000 patients after diagnostic or therapeutic artery catheterisation. In 34 of those patients symptoms of peripheral artery disease occurred. Sixteen of those 34 cases were transferred to our clinic for excimer laser angioplasty. All 16 patients presented with symptoms of acute peripheral artery disease within 1-14 days: superficial femoral artery (SFA) occlusions (4 cases); superficial femoral artery stenosis (3 cases); high-grade stenosis of the common femoral artery (CFA; 3 cases); high-grade stenosis of CFA; SFA and profund femoral artery (PFA; 3 cases); and occlusions of CFA, SFA and PFA (3 cases). Before any procedure was performed, informed consent was given by the patient, which included the use of the Angio-Seal closure device. Every patient who had to undergo recanalisation procedures gave additional informed consent which especially included the usage of the excimer laser for recanalisation. A measurement of the walking distance, ankle-brachial systolic pressure index (ABI) and diagnostic angiography was performed in 13 cases before and immediate after as well as 3 and 6 months after therapeutic percutaneous transluminal laser angioplasty followed by balloon angioplasty (PTLA/PTA). In 3 patients the risks of PTLA/PTA was considered too high; those patients underwent surgical repair. Angiographic and clinical improvement was achieved in 13 of 13 patients. The mean walking distance increased from 81 to > 400 m. The average ankle-brachial systolic pressure index (ABI) increased from 0.47 to 0.84. One patient developed a dissection of the SFA, and in 1 case a peripheral embolisation was seen. The PTLA/PTA technique is a successful therapeutic option for patients with femoral artery occlusion or high-grade stenosis after Angio-Seal application.

Lasers Med Sci. 2001;16(2):90-100Excimer laser (308 nm) recanalisation of in-stent restenosis: thermal considerations.Papaioannou T, Yadegar D, Vari S, Shehada R, Grundfest WS

Laser Research and Technology Development Program, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. papaioan@usc.edu

Excimer laser recanalisation of in-stent restenosis may be a viable modality for improving coronary patency. However, the presence of arterial stents modifies the thermal properties of the irradiated area and may alter temperature patterns generated during ablation. The goal of this study was to evaluate, in vitro, temperature changes during excimer laser ablation of stented vessels and compare them with those obtained from unstented (control) vessels. Six different stent types (AVE Microstent-II, AVE-GFX, ACS Multi-link, JJ Palmaz-Schatz, JJ Crown, and NIR) were deployed in freshly excised porcine coronary vessels. Three control unstented samples were also measured. Blood or saline was infused through the vessels, while the tissue environment was kept at approximately 37 degrees C. A 308 nm excimer laser (Spectranetics, CVX300) with an eccentric 2.0 mm laser catheter (Spectranetics, EII) delivered two trains of 200 pulses each, 10 s apart, at 60 mJ/mm2, and 40 Hz, simulating maximum clinical exposure. The catheter was positioned midway in the stent, first coaxially parallel to the vessel wall, and then at an angle against the stent and vessel wall. Temperature measurements (n= 168 for

blood, n=96 for saline) were performed with a approximately 210 microm diameter, fast-response thermocouple with 0.1 degrees C resolution. The probe was positioned to within approximately 250 microm from the inner surface of the vessels. Tissue temperature was measured at the catheter tip and at the distal and proximal edges of the stents. Maximum recorded temperatures for coaxial and angular alignment, did not exceed 42.2 degrees C (approximately 6 degrees C above baseline) and 54.2 degrees C (approximately 18.1 degrees C above baseline) respectively, for all stents types tested, controls, and all probe locations. Both stented and unstented vessels exhibited comparable temperature gradients. The observed maximum temperatures, obtained under extreme lasing conditions, indicated that 308 nm ablation, in the presence of stents under blood or saline infusion, produces clinically acceptable temperatures.

Lasers Med Sci. 2001;16(2):72-7Excimer laser revascularisation: current indications, applications and techniquesTopaz O, Das T, Dahm J, Madyhoon H, Perin E, Ebersole D

Medical College of Virginia, Virginia Commonwealth University, Richmond 23249, USA.

The ultraviolet pulsed excimer laser (308 nm wavelength) is currently the only laser approved by the FDA for percutaneous intervention in patients with ischemic coronary artery disease. The clinical presentation of the treated patients varies from stable and unstable angina to acute myocardial infarction. Potential advantages of excimer laser revascularisation in acute coronary syndromes and in ischaemic obstructive peripheral vascular disease include concomitant plaque debulking and thrombus removal; absence of systemic lytic state; shortened thrombus clearing time and facilitation of adjunct balloon angioplasty and stenting. Improved understanding of laser-tissue interactions and positive clinical outcomes through the use of safe lasing techniques have led to expansion of indications/applications for laser angioplasty. These include stent restenosis, complex lesions and thrombotic stenoses, bifurcation lesions, balloon failure, total occlusions, focal saphenous vein graft lesions and peripheral arterial obstructions. The excimer laser can be effectively utilised in patients with depressed left ventricular ejection fraction and does not require implantation of a temporary pacemaker as no-reflow phenomenon and severe arrhythmias are rarely encountered. Careful case selection, proper utilisation of equipment and incorporation of efficient lasing techniques play a crucial role in effective and safe cardiovascular laser applications.

Lasers Surg Med. 2001;29(5):455-63Vascular procedures that thermo-coagulate collagen reduce local plateletdeposition and thrombus formation: laser and laser-thermal versus balloonangioplastyAbela GS, Hage-Korban EE, Tomaru T, Barbeau GR, Abela OG, Friedl SE

Department of Medicine, Division of Cardiology, Michigan State University, EastLansing, Michigan 48824, USA. abela@pilot.msu.edu

Background And Objective: Exposure of the arterial wall matrix to blood leads to platelet deposition resulting in thrombosis. Because heat alters tissue matrix we proposed that heating reduces platelet deposition.

Study Design/Materials And Methods: Sixty arterial homografts (15 dogs) were mounted in an arterio-venous "shunt." Interventions included balloon angioplasty (BA), direct laser (LA), laser-thermal (LTA), and combined LTABA. 111Indium-labeled platelets were circulated, radio activity measured, and homografts processed for histology.

Results: Radioactivity count (mean+/- SE) at BA sites (13,853+/-3,192 cpm/cm(2)) was greater than LA (7,038+/-981), LTA (5,294 +/-1,145), LTABA (6,176+/-1,571), and control (1,826+/-339), P<0.05. Electron microscopy showed fewer platelets at LA, LTA, and control than BA sites. BA spread the collagen on the arterial lumen while heat gelled collagen and confined it to the arterial media.

Conclusions: Heating the artery and gelling collagen during LA, LTA, or LTABA significantly reduced thrombogenicity.

Lasers Med Sci. 2001;16(2):101-7

Percutaneous peripheral revascularisation with excimer laser: equipment, technique and resultsDas TSPresbyterian Heart Institute, Dallas, TX 75231, USA. tdas@mail.centrimed.com

Laser angioplasty has been evaluated for coronary applications since the early 1980s. Early complications of dissection, perforation and thermal injury led to a loss of enthusiasm for this technique. Recent advances in catheter development, including optimally spaced laser fibres, athermic 308 nm wave-length catheters, and saline infusion techniques have produced larger laser channels, minimised thermal injury and significantly reduced vessel dissection. This improvement in equipment and technique has led to the growing use of lasers in the field of percutaneous treatment of peripheral vascular interventions. Convincing data supporting laser use in thrombus may lead to widespread use of laser in diffuse, thrombotic, long occlusions in the SFA (superficial femoral artery) and for infrapopliteal disease treatment in patients with non-healing ulcers. Little literature exists on the specific results of 308 nm Excimer laser catheter use for peripheral angioplasty. Significant research is still needed to prove the role of debulking in peripheral applications, but upcoming clinical trial data from the PELA (peripheral angioplasty vs. laser study in long SFA occlusions) and LACI (laser angioplasty in chronic ishaemia) may help to solve these questions in the near future. This article attempts to outline the technical issues of laser catheter use in percutaneous peripheral interventions, including access, sheath selection and wire techniques to cross even the most challenging obstructions in the peripheral circulation.

Lasers Surg Med. 2001;28(4):381-8Endovascular photodynamic therapy using mono-L-aspartyl-chlorin e6 to inhibitIntimal hyperplasia in balloon-injured rabbit arteriesNagae T, Aizawa K, Uchimura N, Tani D, Abe M, Fujishima K, Wilson SE, Ishimaru S

Department of Surgery, Tokyo Medical University, Tokyo, Japan.tnagae@tokyo-med.ac.jp

Background And Objective: Intimal hyperplasia (IH) leading to restenosis is a major complication of arterial revascularization. The purpose of this study was to investigate the effect of photodynamic therapy (PDT) using mono-L-aspartyl chlorin e6 (NPe6) as a photosensitizer and intraluminal radial irradiation for inhibition of IH experimentally.

Study Design/Materials And Methods: Study of laser transmission through the bloodindicated that exclusion of blood is a prerequisite for intraluminal PDT. For homogeneous radial laser irradiation to the vessel wall, we used a newly developed cylindrical diffusing balloon laser fiber. Injuries were induced by pulling a balloon catheter through the right iliac artery of rabbits. One and 6 hours after the NPe6 injection (5mg/kg i.v.), drug distribution was examined by fluorescence microscopy. Nineteen rabbits received NPe6 at the time of injuriesand PDT was performed with 664-nm laser at 30 and 10 J/cm(2) (20, 30, 40 mW/cm(2)) 1 hour after the injuries. The arteries were harvested at 2 days. In a second group of rabbits, PDT was given at 30 mW/cm(2) (30 J/cm(2)). Two weeks after treatment, the arteries were removed and examined histologically.

Results: NPe6 was found to be distributed selectively in the injured media. Endovascular NPe6-PDT showed complete depletion of smooth muscle cells even with 10 J/cm(2) at 2 days. IH was significantly inhibited at 14 days after PDT.

Conclusions: Endovascular PDT of injured artery using NPe6 can prevent IH in this model of arterial wall injury and may become clinically useful for the prophylaxis of IH.

Lasers Surg Med. 2001;29(2):185-92Application of excimer laser angioplasty in acute myocardial infarctionTopaz O, Shah R, Mohanty PK, McQueen RA, Janin Y, Bernardo NL

Division of Cardiology, McGuire VA Medical Center, Medical College of VirginiaHospitals, 1201 Broad Rock Road, Richmond, VA 23249, USA.

background and objective: Patients presenting with acute myocardial infarctionwho fail to respond to standard therapy with thrombolytics or have contraindications for their use oftentimes need revascularization with a mechanical device for removal of an occlusive coronary thrombus and its underlying atherosclerotic plaque. As both thrombi and plaques absorb laser energy in the ultraviolet wavelength (308 nm), we studied the feasibility and safety of excimer laser angioplasty in selective patients with complicated acute myocardial infarction.

Study Design/Materials And Methods: Fifty patients with acute myocardial infarction complicated by continuous chest pain and/or ischemia who had a total of 54 obstructive lesions were treated with percutaneous excimer coronary laser angioplasty (ELCA). A Q-wave myocardial infarction was documented in 56% and a non-Q-wave myocardial infarction in 44%. The baseline left ventricular ejection fraction was reduced at 43 +/- 13% and six patients (12%) presented to the cardiac catheterization laboratory in cardiogenic shock. Twenty-nine patients failed to respond to thrombolytic therapy and 16 had contraindications for thrombolytics and IIb/IIIa receptor antagonists. Following laser debulking, all patients received adjunct balloon dilation and then stents were deployed in 83% of the target lesions. Quantitative coronary arteriography (QCA) was performed at an independent core laboratory.

Results: Ninety-eight percent laser success and 100% procedural success were achieved. By QCA the minimal luminal diameter increased from baseline of 0.7 +/- 0.5 to 1.3 +/- 0.5 mm post-lasing and then to 2.0 +/- 0.6 with balloon dilation to a final of 3.0 +/- 0.5 mm. Pre-laser percent stenosis diameter of 77 +/- 17% was reduced to 51 +/- 22% post-laser to 3.0 +/- 17% post-balloon and to a final of 15 +/- 25%. An 83% laser-induced reduction of thrombus burden area was achieved as well as an increase in TIMI flow from baseline of 1.7 +/- 1.1 to 2.8 +/- 0.4 by laser to a 2.9 +/- 0.4 final. There were no deaths, emergency bypass surgery, cerebral vascular accident, neurologic injury, or major perforation. In one case, a laser-induced major dissection was successfully treated by stenting. All 50 patients survived the procedure, improved clinically, and were discharged.

Conclusion: Application of excimer laser coronary angioplasty is feasible and safe in selected patients with acute myocardial infarction who either fail to respond to thrombolytics or have contraindications to these agents. Intracoronary thrombus at the target lesion can be successfully dissolved with this wavelength laser energy without adverse effect on the procedure results.

Lasers Med Sci. 2001;16(2):84-9Excimer laser coronary angioplasty (ELCA) for diffuse in-stent restenosis: beneficial long-term results after sufficient debulking with a lesion-specific approach using various laser cathetersDahm JB

Department of Cardiology, Ernst-Moritz-Arndt University Greifswald, Germanydahm@mail.uni-greifswald.de

Although brachytherapy became frequently used technique for treating in-stent restenosis (ISR) in 2000 (stenosis recurrence: 14-25%), removing the tissue (i.e., debulking) is still under evaluation. Regarding XeCl Excimer laser no randomised trials have been completed so far. The entirely attainable and published data originate from five one-centre and one multicentre registries which showed a high procedural success-(98%) and a very low complication rate (<2%), but heterogeneous results based on (I) manifold laser- and lasing technology due to evolving catheter and lasing technology during the studies and (II) inhomogeneous patient-populations, which had been documented only occasionally, although we now know that ISR-recurrence rates are significantly higher in patients with (1) high grade stenosis (>70%), (2) long lesions (>15mm in length), (3) recurrent ISR. (4) ISR in saphenous vein grafts, (5) early-ISR (<3 months after stent implantation), (6) multi-vessel disease and (7) low ejection fraction. Because all athero-ablative procedures are typically finalized by adjunctive balloon PCI, diameter stenosis before adjunctive PTCA was between 23% and 64%, reflecting the different lasing (and therefor debulking) intensity between the studies. The mean lesion-length, vessel diameter, stent-type and coronary differed significantly between the studies (i.e. mean lesion length between 14 and 32 mm) and although of major influence, the speed of lasing (=ablation) was not recorded in the various studies. Concerning eccentric ELCA

the invention of the area-ablation technique provide a significant greater ablation effect and the new OS-technology provide 60% more ablating area. In summary, the feasibility, effectiveness, procedural success and presumably long-term outcome of the Excimer laser for treating ISR depend on multiple outcome-influencing aspects. The lack of recording variables make analysis of various laser-for-ISR trials difficult or even impossible. ELCA seems to have advantageous procedural and long term results in lesions, where aggressive debulking effect using eccentric ELCA catheters can be achieved. The OS-catheter can provide a maximum debulking in distal lesions and tortuous vessels, where the debulking abilities of the eccentric catheter are limited. If laser debulking is inadequate (DS 30%), the incidence of recurrent restenosis appear to be higher and brachytherapy is probably more suitable. Sufficient laser debulking can only be achieved through use of precise technique respecting the laser-specific abilities of plaque dissolution, appropriate energy levels and quantities, and possibly recovery time.

Lasers Med Sci. 2001;16(2):72-7Excimer laser revascularisation: current indications, applications and techniquesTopaz O, Das T, Dahm J, Madyhoon H, Perin E, Ebersole D

Medical College of Virginia, Virginia Commonwealth University, Richmond 23249, USA

The ultraviolet pulsed excimer laser (308 nm wavelength) is currently the only laser approved by the FDA for percutaneous intervention in patients with ischemic coronary artery disease. The clinical presentation of the treated patients varies from stable and unstable angina to acute myocardial infarction. Potential advantages of excimer laser revascularisation in acute coronary syndromes and in ischaemic obstructive peripheral vascular disease include concomitant plaque debulking and thrombus removal; absence of systemic lytic state; shortened thrombus clearing time and facilitation of adjunct balloon angioplasty and stenting. Improved understanding of laser-tissue interactions and positive clinical outcomes through the use of safe lasing techniques have led to expansion of indications/applications for laser angioplasty. These include stent restenosis, complex lesions and thrombotic stenoses, bifurcation lesions, balloon failure, total occlusions, focal saphenous vein graft lesions and peripheral arterial obstructions. The excimer laser can be effectively utilised in patients with depressed left ventricular ejection fraction and does not require implantation of a temporary pacemaker as no-reflow phenomenon and severe arrhythmias are rarely encountered. Careful case selection, proper utilisation of equipment and incorporation of efficient lasing techniques play a crucial role in effective and safe cardiovascular laser applications.

Lasers Med Sci. 2001;16(2):133-40Next generation catheters for excimer laser coronary angioplastyTaylor K, Reiser C

Spectranetics, Colorado Springs, CO 80907, USA. kevin.taylor@spectranetics.com

In response to the need for maximising debulking in complex lesions, three new excimer laser coronary angioplasty catheter designs have been introduced. The eccentric laser catheter features a fibreoptic bundle disposed opposite the guide-wire lumen at the catheter tip and a torque mechanism that allows the user to rotate the fibre bundle toward the lesion mass. Residual lumens 50% larger than the catheter tip diameter have been obtained when multiple passes were made, with each pass performed using a different tip rotation. A recent case series utilising this catheter in restenosed stents resulted in larger lumens and lower 6-month restenosis rates. The optimal spaced (OS) laser catheter features a fibre bundle placed concentrically around the guide-wire lumen. The 61 microm diameter core fibres are spaced at a nominal centre-to-centre distance of 90 microm, resulting in a 40% increase in ablative area as compared to previous concentric catheter designs. In vitro testing and clinical evaluation demonstrated OS catheters routinely achieve an ablated area > or =90% of the catheter tip size. The 0.9 mm catheter features a high-density fibre pack composed of 65 fibres.Peripheral dead space has been minimised to maximise penetration of calcified plaque. When combined with laser parameters of up to 80 mJ/mm2, and 80 Hz pulse repetition rate, the catheter demonstrated improved hard tissue and calcified tissue penetration in vitro. Clinical evaluation in Canada revealed a 94% lesion recanalisation rate in high-grade stenoses with angiographic evidence of calcification, chronic total occlusions, and lesions which have failed balloon angioplasty.

Lasers Med Sci. 2001;16(2):122-9

Current multicentre studies with the excimer laser: design and aims.Tcheng JE, Volkert-Noethen AA

Duke University Medical Center, Durham, NC 27710, USA

Excimer laser ablation to remove atherosclerotic plaque has been used for over a decade as a methodology to treat cardiovascular disease. Improvements in the technique and technology of excimer laser angioplasty, coupled with the recognition of new clinical opportunities for this treatment modality, have resulted in a resurgence of interest in the laser. Three clinical trials are now being conducted to explore potential applications, including the LARS trial of excimer laser versus balloon angioplasty to treat in-stent restenosis, the PELA trial of excimer laser angioplasty in occluded superficial femoral artery disease, and the LACI trial of excimer laser angioplasty in limb-threatening ischaemia. This article describes the rationale and objectives of these new approaches to some of the more challenging problems in cardiovascular disease.

Lasers Med Sci. 2001;16(2):108-12Application of excimer laser coronary angioplasty (ELCA) in bifurcation lesionsMadyoon H, Croushore L

Cardiac Catheterization Laboratory, St Joseph's Medical Center, Stockton, CA 95204, USA cardiology@2xtreme.net

Excimer laser coronary angioplasty (ELCA) offers a unique approach to the treatment of bifurcation lesions that continues to present a challenge in percutaneous coronary intervention. Debulking plaque prior to stenting or balloon angioplasty has demonstrated significant improvement in the treatment of bifurcation lesions. Clot dissipation properties of excimer laser combined with its ability to debulk, makes this device unique when applied to thrombus-laden bifurcation lesions. ELCA is the only debulking technique that allows retention of two guide wires with resultant protection of the bifurcation vessels during the debulking procedure. We herein describe three patients with unstable angina who underwent a debulking procedure with ELCA involving application of single and double wire techniques. These three cases illustrate two different techniques used for debulking bifurcation lesions. Both single and double wire techniques are described. ELCA can be used safely and effectively in high-risk patients with bifurcation lesions, even in the presence of thrombus.

Lasers Surg Med. 2001;28(3):212-5Intravascular low-power laser irradiation after coronary stenting: long-term follow-upDe Scheerder IK, Wang K, Kaul U, Singh B, Sahota H, Keelan MH, Kipshidze NN, Moses J

University Hospitals, Leuven, Belgium

Background And Objective: A high restenosis rate remains a limiting factor for percutaneous transluminal coronary angioplasty and stenting. The objective of this study was to evaluate the effect of intravascular red laser therapy (IRLT) on restenosis after stenting procedures in de novo lesions.

Study Design/Materials And Methods: A total of 68 consecutive patients were treated with IRLT in conjunction with coronary stenting procedures. Mean lesion length was 16.5 +/- 2.4 mm. Reference vessel diameter (RVD) and pre-minimal lumen diameter (MLD) were 2.90 +/- 0.15 mm and 1.12 +/- 0.26 mm, respectively.

Results: After treatment, MLD was 2.76 +/- 0.32 mm with no procedural complications or in-hospital adverse events. Angiographic follow-up (n = 61) revealed restenosis in nine patients (14.7%) with rate by artery size of > 3 mm (n = 21) 0%; 2.5--3.0 mm (n = 28) 14.2%; and < 2.5 mm (n = 12) 41.6%.

Conclusion: Intravascular red light therapy is safe, feasible, and reduces expected restenosis rate after coronary stenting.

Catheter Cardiovasc Interv. 2000 Dec;51(4):500-4Percutaneous transluminal laser guide wire recanalization of chronic subclavianartery occlusion in symptomatic coronary-subclavian steal syndrome

Eggebrecht H, Naber CK, Oldenburg O, Herrmann J, Haude M, Erbel R, Baumgart D

Department of Cardiology, Division of Internal Medicine, University HospitalEssen, Essen, Germany. holger.eggerbrecht@uni-essen.de

Treatment of subclavian artery stenosis by percutaneous balloon angioplasty and adjunctive stent placement was shown to be safe and efficacious, but it may be limited in tight stenoses and long occlusions. We describe the case of a patient who experienced progressive angina pectoris associated with signs of cerebrovertebral insufficiency 9 yr after bypass surgery, including left internal mammary artery (LIMA) grafting to the left anterior descending coronary artery. Angiography showed reversed flow through the LIMA graft into the subclavian artery and a 4-cm occlusion beginning at the origin of the left subclavian artery, representing a rare coronary-subclavian steal syndrome. After a conventional approach failed, recanalization was performed successfully using laser guide wire angioplasty with adjunctive stent placement in a combined radial and femoral approach.

J Med Assoc Thai. 2000 Nov;83 Suppl 2:S179-86Acute and follow-up results of laser angioplasty: single center experienceMahanonda N, Khuanprasert S, Tresukosol D, Panchavinnin P, Phankingthongkum R,Chotinaiwattarakul C, Kangkagate C, Sukrungreang C, Suriyabantaeng S, ChirachevinW, Jaidee T, Kaeokam-Aim S, Chaithiraphan S

Her Majesty Cardiac Center, Faculty of Medicine Siriraj Hospital, MahidolUniversity, Bangkok.

Excimer laser angioplasty was used to treat total occluded coronary arteries and instent restenosis lesions with high success rate. To assess immediate and long-term results of patients treated with excimer laser, we analyzed demographic information and the immediate results of 44 patients who underwent ELCA. The patients were followed up and assessed for clinical restenosis. The initial success rate of ELCA was 86.4 per cent which is comparable to plain balloon angioplasty performed during the same period. Clinical restenosis was 29 per cent. In conclusion, ELCA for patients with coronary artery disease can be performed with initial high success rate and reasonable long-term restenosis.

Am J Cardiol. 2000 Nov 1;86(9):927-30Long-term follow-up after coronary stenting and intravascular red laser therapyDe Scheerder I, Wang K, Nikolaychik V, Kaul U, Singh B, Sahota H, Keelan MH,Kipshidze N

University Hospitals, Leuven, Belgium

A high restenosis rate remains a limiting factor for coronary angioplasty and stenting. Recently, use of intravascular red light therapy (IRLT) has been shown to be effective in different animal models and in humans in reducing the restenosis rate. Sixty-eight patients were treated with IRLT in conjunction with coronary stenting procedures. Mean age was 64 +/- 9 years. Treated lesions were type A (11), type B (42), and type C (18) with a mean lesion length of 16.5 +/- 2.4 mm. Reference vessel diameter and minimal lumen diameter (MLD) before therapy were 2.90 +/- 0.15 and 1.12 +/- 0.36 mm, respectively. After stenting and laser irradiation, MLD was 2.76 +/- 0.39 mm. No procedural complications or in-hospitaladverse events occurred. All patients were followed up as depicted in the protocol. Sixty-one patients underwent angiographic restudy, which revealed restenosis in 9 patients (14.7%). Observed restenosis rate by artery size was > 3 mm (n = 21, 0%), 2.5 to 3.0 mm (n = 28, 14.2%), and <2.5 mm (n = 12, 41.6%). We conclude that IRLT is safe and feasible and reduces the expected restenosis rate in patients after coronary stenting in arteries of >2.5 mm.

J Med Assoc Thai. 2000 Nov;83 Suppl 2:S179-86

Acute and follow-up results of laser angioplasty: single center experienceMahanonda N, Khuanprasert S, Tresukosol D, Panchavinnin P, Phankingthongkum R,Chotinaiwattarakul C, Kangkagate C, Sukrungreang C, Suriyabantaeng S, ChirachevinW, Jaidee T, Kaeokam-Aim S, Chaithiraphan S

Her Majesty Cardiac Center, Faculty of Medicine Siriraj Hospital, MahidolUniversity, Bangkok.

Excimer laser angioplasty was used to treat total occluded coronary arteries and instent restenosis lesions with high success rate. To assess immediate and long-term results of patients treated with excimer laser, we analyzed demographic information and the immediate results of 44 patients who underwent ELCA. The patients were followed up and assessed for clinical restenosis. The initial success rate of ELCA was 86.4 per cent which is comparable to plain balloon angioplasty performed during the same period. Clinical restenosis was 29 per cent. In conclusion, ELCA for patients with coronary artery disease can be performed with initial high success rate and reasonable long-term restenosis.

Eur Heart J. 2000 Nov;21(21):1797-805Total occlusion trial with angioplasty by using laser guidewire. The TOTAL trialSerruys PW, Hamburger JN, Koolen JJ, Fajadet J, Haude M, Klues H, Seabra-Gomes R,Corcos T, Hamm C, Pizzuli L, Meier B, Mathey D, Fleck E, Taeymans Y, Melkert R, Teunissen Y, Simon R

Department of Interventional Cardiology, Heart Centre of the University Hospital Rotterdam, Rotterdam, The Netherlands

Aims: A randomized trial was performed to assess the safety and efficacy of alaser guidewire, in the treatment of chronic coronary occlusions.

Methods And Results: In 18 European centres, 303 patients with a chronic coronary occlusion were randomized to treatment with either the laser guidewire (n=144) or conventional guidewires (mechanical guidewire, n=159). The primary end-point of the study was treatment success, defined as reaching the true lumen distal to the occlusion by the allocated wire within 30 min of fluoroscopic time: laser guidewire vs mechanical guidewire; 52.8% (n=76) vs 47.2% (n=75), P=0.33. Serious adverse events following the initial guidewire attempt were 0% (laser guidewire) and 0.6% (mechanical guidewire), respectively. Angioplasty (performed following successful guidewire crossing) was successful in 179 patients (91%, laser guidewire n=79, mechanical guidewire n=100), followed by stent implantation in 149 (79%). At the 6-month angiographic follow-up, the difference in binary restenosis rate (laser guidewire vs mechanical guidewire; 45.5% vs 38.3 %, P=0.72) or reocclusion rate (25.8% vs 16.1%, P=0.15) did not reach statistical significance. At 1, 6 and 12 months, angina and event-free survival were 69%, 35% and 24% (laser guidewire) vs 74%, 40% and 31% (mechanical guidewire).

Conclusion: Although laser guidewire technology was safe, the increase in crossing success did not reach statistical significance.

Int J Cardiovasc Intervent. 2000 Sep;3(3):153-160Laser angioplasty of peripheral arteries after unsuccessful recanalization of thesuperficial femoral arterySteinkamp HJ, Werk M, Haufe M, Felix R

Department of Radiology, Interventional Angiology, University Clinic Charité,Berlin, Germany

Aim: To demonstrate the range of applying laser angioplasty after unsuccessful recanalization of the superficial femoral artery (SFA) with conventional interventional techniques.

Materials And Methods: In a prospective trial in 94 cases with occlusion of the SFA and formerly unsuccessful conventional percutaneous transluminal angioplasty, laser angioplasty for recanalization was applied. The average occlusion length of the SFA was 17.5 cm (range 4-

36 cm). The recanalization attempt was made using the crossover technique in 78 patients, in eight patients with the antegrade technique and in another eight patients using the transpopliteal technique. The primary recanalization attempt was performed with Terumo wires (curved and straight) as well as different catheters (Multipurpose/Vertebralis/Cobra). After the unsuccessful recanalization attempt the laser catheter was applied.

Results: The application of laser angioplasty demonstrated a successful recanalization of the SFA in 76/94 patients (80.9%). In18 patients (19.1%) the recanalization was not possible even with percutaneous transluminal laser angioplasty (PTLA). The reason for the unsuccessful PTLA wasin 10 cases due to obstructing calcified material, which was resistant to PTLA application. In four cases obstructing calcifications caused the laser catheter to be positioned in subintimal tissue, resulting in perforation of the SFA. In another four patients there was an aberrant anatomy of the SFA which resulted in a direct vessel injury after advancing the laser catheter. After a follow-up period of 12 months primary, primary-assisted and secondary patency rates were50.0%, 65.8% and 73.7%, respectively.

Discussion: In primarily unsuccessful recanalization of the SFA, PTLA allows in 80% of cases a successful recanalization of the SFA. The technical success rate and the patency rate support the application of PTLA.

J Biomed Mater Res. 2000 Sep 5;51(3):520-8Surface microarchitectural design in biomedical applications: in vivo analysis oftissue ingrowth in excimer laser-directed micropored scaffold for cardiovascular tissue engineering.Nakayama Y, Nishi S, Ishibashi-Ueda H, Matsuda T

Department of Bioengineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan

A micropatterned microporous segmented polyurethane film (20 x 12 mm in size, 30 micrometer thick) with four regions was prepared by excimer laser microprocessing to provide an in vivo model of transmural tissue ingrowth in an open cell-structured scaffold specially designed for cardiovascular tissue engineering. Three microporous regions had the same circular micropores (30 micrometer diameter) but different pore density arrangements (percentage of total pore area against unit area was 0.3%, 1.1%, and 4.5%), and the other region remained nonporous. The covered stent, prepared by wrapping the regionally different density-microporous film on an expandable metallic stent (approximately 3.1 mm in diameter), was delivered to the luminal surface of canine common carotid arteries and placed after expansion of the stent to a diameter of approximately 8 mm using a balloon catheter. At 4 weeks of implantation, all the covered stents (n = 10) were patent. The luminal surfaces of the covered stents were almost confluently endothelialized both in nonporous and microporous regions. Histological examination showed that the neointimal wall was formed by tissue ingrowth from host through micropores (transmural) and anastomotic sites. Thrombus formation occurred frequently in the lowest density porous region and nonporous region. With an increase in pore density, the thickness of the neointimal wall decreased. This study demonstrated how the micropore density of implanted devices influences tissue ingrowth in arterial implantation.

J Biomed Mater Res. 2000 Sep 5;51(3):520-8Surface microarchitectural design in biomedical applications: in vivo analysis of tissue ingrowth in excimer laser-directed micropored scaffold for cardiovascular tissue engineeringNakayama Y, Nishi S, Ishibashi-Ueda H, Matsuda T

Department of Bioengineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.

A micropatterned microporous segmented polyurethane film (20 x 12 mm in size, 30 micrometer thick) with four regions was prepared by excimer laser microprocessing to provide an in vivo model of transmural tissue ingrowth in an open cell-structured scaffold specially designed for cardiovascular tissue engineering. Three microporous regions had the same circular micropores (30 micrometer diameter) but different pore density arrangements (percentage of total pore area against unit area was 0.3%, 1.1%, and 4.5%), and the other region remained nonporous. The covered stent, prepared by wrapping the regionally different density-microporous film on an expandable metallic stent (approximately 3.1 mm in diameter),

was delivered to the luminal surface of canine common carotid arteries and placed after expansion of the stent to a diameter of approximately 8 mm using a balloon catheter. At 4 weeks of implantation, all the covered stents (n = 10) were patent. The luminal surfaces of the covered stents were almost confluently endothelialized both in nonporous and microporous regions. Histological examination showed that the neointimal wall was formed by tissue ingrowth from host through micropores (transmural) and anastomotic sites. Thrombus formation occurred frequently in the lowest density porous region and nonporous region. With an increase in pore density, the thickness of the neointimal wall decreased. This study demonstrated how the micropore density of implanted devices influences tissue ingrowth in arterial implantation.

Am J Cardiol. 2000 Aug 15;86(4):390-4Six-month outcome after excimer laser coronary angioplasty for diffuse in-stent restenosis in native coronary arteriesHamburger JN, Foley DP, de Feyter PJ, Wardeh AJ, Serruys PW

Department of Interventional Cardiology, Thoraxcenter, University HospitalRotterdam, Rotterdam, The Netherlands.

This study evaluated the intermediate-term follow-up after excimer laser coronary angioplasty (ELCA) and adjunctive percutaneous transluminal coronary angioplasty (PTCA) in patients with diffuse in-stent restenosis (lesion length >10 mm). Clinical and angiographic follow-up were performed at 6 months. Quantitative coronary angiography performed at 3 stages-during stent implantation, before and after ELCA + PTCA, and at follow-up-included measurements of the minimum lumen diameter (MLD) and percent diameter stenosis (DS). Sixteen consecutive patients were included. The (median + range) stent length was 36 mm (range 15 to 105), with a restenotic lesion length of 32 mm (range 10 to 90). After ELCA + PTCA, the MLD increased from 0.60 +/- 0.41 to 2.28 +/- 0.50 mm, whereas the DS decreased from 76 +/- 16% to 22 +/- 8%. Despite adjunctive high-pressure PTCA, the MLD after ELCA + PTCA remained smaller than the MLD after initial stent implantation, (2.28 +/- 0. 50 mm vs 2.67 +/- 0.32 mm, p = 0.014). Adverse events included ELCA-related acute coronary occlusion in 4 patients and a per-procedural intracerebral hematoma in 1. At 6 months, there was recurrence of angina in all patients. Angiographic follow-up was completed in 13 patients (87%), showing a reocclusion in 6 (46%), a >50% DS in 6 (MLD 1.03 +/- 0.87 mm, DS 68 +/- 24%), and a distal de novo lesion in 1. Despite satisfactory acute angiographic results, the recurrence of significant restenosis in all patients suggests that ELCA + PTCA is not a suitable stand-alone therapy for diffuse in-stent restenosis of long stented segments.

Int J Card Imaging. 2000 Aug;16(4):267-77Evaluation of the long-term functional outcome assessed by myocardial perfusion scintigraphy following excimer laser angioplasty compared to balloon angioplasty in longer coronary lesionsAppelman YE, Piek JJ, van der Wall EE, Redekop WK, van Royen EA, Fioretti PM, de Feyter PJ, Koolen JJ, Strikwerda S, Serruys PW, David GK, Tijssen JG, Lie KI

Department of Cardiology, Clinical Epidemiology and Biostatistics, Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.

Objectives: Evaluation of the long-term functional outcome assessed by exercise myocardial perfusion imaging following excimer laser angioplasty compared to balloon angioplasty in coronary lesions > 10 mm in length.

Background: Previous randomized studies evaluating the effect of coronary interventions mainly focused on the long-term clinical and angiographic outcome. The functional outcome, assessed by myocardial perfusion scintigraphy, has not been evaluated in a randomized setting.

Methods: A total of 308 patients with stable angina and a longer coronary lesion (> 10 mm) were randomized to excimer laser angioplasty or balloon angioplasty. A 99mTechnetium-2-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography (SPECT) study was performed in 139 patients before the initial angioplasty procedure and at 6 months follow-up (73 patients in the laser group versus 66 patients in the balloon group, respectively). Exercise tolerance at follow-up was compared to baseline values by means of exercise duration and double product at peak exercise. Myocardial perfusion of the randomized vascular bed was assessed semi-quantitatively on the MIBI SPECT images. The reversible defects were graded as mild, moderate or severe. Myocardial perfusion at follow-up was expressed as a percentage reduction in incidence and grading of the reversible defects compared to baseline values.

Results: Forty-four (61%) patients assigned to laser angioplasty were asymptomatic at 6 months follow-up compared to 34 (52%) patients assigned to balloon angioplasty (p = NS). Improvement in exercise duration and double product were 0.7 +/- 2.1 min and 4.3 +/- 6.2 min/mmHg/l,000, respectively, in the laser group, versus 0.3 +/- 2.5 min and 3.1 +/- 5.5 min/mmHg/1,000, respectively, in the balloon group (both p = NS). The percentage reduction of reversible defects was 23% in patients assigned to laser angioplasty vs. 29% in patients assigned to balloon angioplasty (Relative risk [RR]: 0.79, 95% confidence interval [CI]: 0.40-1.57; p = 0.50). The mild, moderate and severe reversible defects improved in 44.4, 63.6 and 66.6%, respectively, in the laser angioplasty group vs. 66.6, 53.8 and 90%, respectively, in the balloon angioplasty group. None of the comparisons were significantly different.

Conclusion: Excimer laser angioplasty compared to balloon angioplasty in coronary lesions > 10 mm in length yields a similar long-term functional outcome assessed by anginal status, exercise tolerance and myocardial perfusion.

J Invasive Cardiol. 2000 Jul;12(7):335-42High-energy eccentric excimer laser angioplasty for debulking diffuse iIn-stent restenosis leads to better acute- and 6-month follow-up resultsDahm JB, Kuon E

Department of Cardiology, Ernst-Moritz-Arndt-University Greifswald, F.-Loeffler-Strasse 23a, 17487 Greifswald, Germany. dahm@mail.uni-greifswald.de

Background: Restenosis of diffuse in-stent stenosis (> 10 mm) treated with percutaneous transluminal coronary angioplasty (PTCA) is as high as 80%. The excessive tissue-hyperplasia led to debulking before PTCA. Because debulking is limited by the intensity and applicability of its use, the large debulking trials were criticized and showed no major benefit. Considering that a significantly greater diameter than its own diameter can be ablated by the Eccentric Excimer Laser (eccELCA), we evaluated its effectiveness and safety in a prospective study.

Methods: Thirty-nine patients with diffuse in-stent restenosis (3.4 +/- 0.6 mm diameter; 14 +/- 9 mm in length) were treated by EccELCA followed by PTCA. In addition to clinical/angiographic target lesion revascularization (TLR) and major adverse cardiac events (MACE), the study endpoints were diameter stenosis (DS) and minimal lumen diameter (MLD), which were calculated before EccELCA, after EccELCA, after adjunctive PTCA and at 6-month follow-up.

Results: Procedural success was 99.8%. Delivered laser energy was 2,134 +/- 856 Joules. DS decreased from 84 +/- 14% to 23 +/- 11% after eccELCA (p = 0.0018) to 9 +/- 5% after PTCA (p = 0.001) and was 31 +/- 12% at follow-up (p = 0.0041). MLD increased from 0.7 +/- 0.2 mm to 2.2 +/- 0.4 mm after EccELCA (p = 0.0017), to 2.7 +/- 0.4 mm after PTCA (p = 0.001) to 1.7 +/- 0.3 mm at follow-up (p = 0.0049). Maximal balloon inflation pressure was 9.4 +/- 4.0 atmospheres. At follow-up angiography, TLR = 23.1%, clinical TLR = 12.8%, and MACE = 0%.

Conclusion: Due to a greater debulking effect, additional lumen gain can be achieved immediately and at follow-up through the high-energy use of EccELCA for debulking and through the use of lower balloon inflation pressures for adjunctive PTCA. Clinical and angiographic TLR is significantly lower than other debulking techniques or PTCA alone and comparable with local irradiation therapy.

J Am Coll Cardiol. 2000 Jul;36(1):69-74Six-month clinical and angiographic outcome after successful excimer laser angioplasty for in-stent restenosis

Köster R, Kähler J, Terres W, Reimers J, Baldus S, Hartig D, Berger J, Meinertz T, Hamm CW

University Hospital Eppendorf, Medical Clinic, Department of Cardiology, Hamburg,Germany

Objectives: This study evaluated the clinical and angiographic six-monthfollow-up after excimer laser coronary angioplasty (ELCA) for restenosed coronarystents.

Background: Excimer laser coronary angioplasty has recently been shown to be safeand efficient for the treatment of in-stent restenosis.

Methods: Ninety-six consecutive patients successfully treated with ELCA within141 stents were included in a six-month clinical and angiographic follow-up.

Results: During follow-up there was one sudden death and one patient with documented myocardial infarction. Angina pectoris classified as > or = Canadian Cardiovascular Society II reoccurred in 49 patients. Follow-up angiography was obtained in 89 patients (93%) with 133 stents. Quantitative coronary angiography revealed a mean diameter stenosis of 77 +/- 10% before intervention, 41 +/- 12% after laser treatment and 11% +/- 12% after adjunctive percutaneous transluminal coronary angioplasty (p < 0.001). Six months after ELCA the mean diameter stenosis had increased to 60 +/- 26% (p < 0.001). A > or =50% diameter stenosis was present in 48 patients (54%); in 24 of these patients diameter stenosis was > or =70%. Total occlusions occurred in an additional 10 patients (11%). There was a trend toward an increased recurrent restenosis rate in patients with diabetes mellitus and long lesions or total occlusions (p = 0.059). Forty-eight patients (50%) received medical treatment after six months. Reinterventions were necessary in 30 patients (31%), and coronary artery bypass surgery was performed in 17 patients (18%). Event-free survival was 50%.

Conclusions: Excimer laser angioplasty for in-stent restenosis was associated with a high incidence of recurrent restenosis in this group of patients, suggesting that this technique is unlikely to reduce recurrent in-stent restenosis and that other approaches are necessary.

Circulation. 2000 May 30;101(21):2484-9Treatment of in-stent restenosis with excimer laser coronary angioplasty versus rotational atherectomy: comparative mechanisms and resultsMehran R, Dangas G, Mintz GS, Waksman R, Abizaid A, Satler LF, Pichard AD, Kent KM, Lansky AJ, Stone GW, Leon MB

Cardiovascular Research Foundation, Lenox Hill Heart & Vascular Institute, New York, NY, USA

Background: Atheroablation yields improved clinical results for balloon angioplasty (percutaneous transluminal coronary angioplasty, PTCA) in the treatment of diffuse in-stent restenosis (ISR).

Methods And Results: We compared the mechanisms and clinical results of excimer laser coronary angioplasty (ELCA) versus rotational atherectomy (RA), both followed by adjunct PTCA; 119 patients (158 ISR lesions) were treated with ELCA+PTCA and 130 patients (161 ISR lesions) were treated with RA+PTCA. Quantitative coronary angiographic and planar intravascular ultrasound (IVUS) measurements were performed routinely. In addition, volumetric IVUS analysis to compare the mechanisms of lumen enlargement was performed in 28 patients with 30 lesions (16 ELCA+PTCA, 14 RA+PTCA). There were no significant between-group differences in preintervention or final postintervention quantitative coronary angiographic or planar IVUS measurements of luminal dimensions. Angiographic success and major in-hospital complications with the 2 techniques were also similar. Volumetric IVUS analysis showed significantly greater reduction in intimal hyperplasia volume after RA than after ELCA (43+/-14 versus 19+/-10 mm(3), P<0.001) because of a significantly higher ablation efficiency (90+/-10% versus 76+/-12%, P = 0.004). However, both interventional strategies had similar long-term clinical outcome; 1-year target lesion revascularization rate was 26% with ELCA+PTCA versus 28% with RA+PTCA (P = NS).

Conclusions: Despite certain differences in the mechanisms of lumen enlargement, both ELCA+PTCA and RA+PTCA can be used to treat diffuse ISR with similar clinical results.

Catheter Cardiovasc Interv. 2000 Apr;49(4):468-71Intravascular low-power red laser light as an adjunct to coronary stent implantation: initial clinical experienceDe Scheerder IK, Wang K, Zhou XR, Szilard M, Verbeken E, Ping QB, Yanming HJianhua H, Van de Warf F

Department of Cardiology, University Hospitals Leuven, Leuven, Belgium

Low-power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo and reduces restenosis in animal models. The present study reports the preliminary clinical experience in our center. Eighty-one patients were treated with LPRLL, 30 mW/1 min, for in-stent restenosis (n = 27), elective stenting for recurrent restenosis (n = 16), and stenting for treatment of a suboptimal PTCA result (n = 38). All interventions were successful and no major adverse events due to LPRLL therapy were observed. At follow-up, 12 patients (14.8%) underwent an early control coronarogram due to target vessel restenosis. At 6 months, another 20 patients showed a significant restenosis of the target vessel. Preliminary clinical evaluation demonstrates that LPRLL is feasible and safe. The preliminary results suggest that LPRLL results in a decrease of in-stent restenosis when used during primary stenting.

Rev Port Cardiol. 2000 Jan;19(1):67-71The angioplasty of chronic coronary occlusions with the excimer laser for debulking followed by stent implantatioAlmeida M, Cavaco DM, Ribeiro MA, Teles RC, Martins V, Machado FP, Baptista J,Palos J, Silva JM, Seabra-Gomes R

Serviço de Cardiologia, Hospital de Santa Cruz, Carnaxide

Coronary angioplasty (PCI) of chronic total occlusions (CTO), even when successful, are associated to less favourable long term results. The recent use of coronary stents has improved the long term outcome of those interventions.

Purpose: To evaluate the short term results and long term occurrence of major adverse coronary events (MACE): death, MI, urgent revascularization and the need for a new target vessel revascularization (TVR) in patients with CTO who had previously been submitted to a PCI with excimer laser for plaque debulking followed by a provisional stent.

Population: From our database, we selected 19 patients with a mean age of 51 +/- 13 years (18 male) submitted to PCI between 1994 and 1998. Of those patients, 10 had had of a previous MI. Hypertension, smoking habits and hypercholesterolemia were present in 9 patients (42%). Two patients had diabetes. The main reason for PCI was stable angina in 16 patients (84%) and unstable in 3 patients (16%). Single-vessel disease was present in 18 patients (94%) and multiple-vessel in 1 patient (6%); left ventricular ejection fraction was preserved in 18 patients (94%). Single vessel PCI was performed in 16 patients (84%) and double vessel in 3 patients. Plaque debulking with excimer laser was performed in all patients,followed by 23 stents (Multilink--8; Gianturco Roubin--5; Palmaz Schatz--4; others--6). The mean clinical follow-up was 19 months.

Results: There were no major short-term clinical events (death, MI or urgent revascularization). During follow-up, TVR was only required in 5 patients (26%), all of them in the first 7 months after PCI.

Conclusions: In the highly selected population, PCI for chronic total occlusion, with excimer laser plaque debulking followed by provisional stents, was a safe procedure with a very acceptable rate of new target vessel revascularization in the follow-up period.

Chin Med J (Engl). 2000 Jan;113(1):14-7Treatment of in-stent coronary restenosis with excimer laser angioplastyLiu M, Chow WH, Kwok OH, Jim MH, Yip A, Fan K, Chan E

Grantham Hospital, Department of Cardiology, First Teaching Hospital, BeijingMedical University, Beijing 100034, China

Objective: To evaluate the efficacy and safety of excimer laser coronary angioplasty (ELCA) with adjunctive balloon angioplasty in patient with in-stent restenosis.

Methods: ELCA was performed in 20 patients of instent restenosis. All patients were symptomatic and had class III-IV angina. ELCA was performed with the Spectranetics CVX-300 System. The laser catheter of Vittesse C (concentric) and E (eccentric) with diameter of 1.4-2.0 mm was used.

Results: Laser catheter crossed all stenotic stents without difficulty. The lesion length was 4.6-51.2 mm, mean 20.7 +/- 13.7 mm, including 14 lesions > 10 mm. Laser treatment alone increased minimal lumen diameter (MLD) from 0.3 +/- 0.3 mm to 1.4 +/- 0.3 mm (P < 0.0001) and improved the diameter stenosis from 88.8% +/- 10.0% to 46.0% +/- 8.0% (P < 0.0001). Adjunctive balloon angioplasty further increased minimal lumen diameter to 2.3 +/- 0.7 mm and reduced diameter stenosis to 14.2% +/- 8.2% (P < 0.0001). At follow-up (1-17 months, mean 8.9 +/- 5.7 months), 17 (85%) patients had remained asymptomatic, 3 (15%) patients had mild to moderate exertional angina, 1 (5%) patient received CABG.

Conclusion: ELCA with adjunctive percutaneous transluminal coronary angioplasty (PTCA) is an efficient and safe technique to debulk tissue in the patient with in-stent restenosis. The incidence of procedural related complication was low and ELCA may be used as a good method for in-stent restenosis treatment.

Rev Port Cardiol. 2000 Jan;19(1):67-71The angioplasty of chronic coronary occlusions with the excimer laser for debulking followed by stent implantationAlmeida M, Cavaco DM, Ribeiro MA, Teles RC, Martins V, Machado FP, Baptista J, Palos J, Silva JM, Seabra-Gomes R

Serviço de Cardiologia, Hospital de Santa Cruz, Carnaxide.

Coronary angioplasty (PCI) of chronic total occlusions (CTO), even when successful, are associated to less favourable long term results. The recent use of coronary stents has improved the long term outcome of those interventions.PURPOSE: To evaluate the short term results and long term occurrence of major adverse coronary events (MACE): death, MI, urgent revascularization and the need for a new target vessel revascularization (TVR) in patients with CTO who had previously been submitted to a PCI with excimer laser for plaque debulking followed by a provisional stent.

Population: From our database, we selected 19 patients with a mean age of 51 +/- 13 years (18 male) submitted to PCI between 1994 and 1998. Of those patients, 10 had had of a previous MI. Hypertension, smoking habits and hypercholesterolemia were present in 9 patients (42%). Two patients had diabetes. The main reason for PCI was stable angina in 16 patients (84%) and unstable in 3 patients (16%). Single-vessel disease was present in 18 patients (94%) and multiple-vessel in 1 patient (6%); left ventricular ejection fraction was preserved in 18 patients (94%). Single vessel PCI was performed in 16 patients (84%) and double vessel in 3 patients. Plaque debulking with excimer laser was performed in all patients, followed by 23 stents (Multilink--8; Gianturco Roubin--5; Palmaz Schatz--4; others--6). The mean clinical follow-up was 19 months.

Results: There were no major short-term clinical events (death, MI or urgent revascularization). During follow-up, TVR was only required in 5 patients (26%), all of them in the first 7 months after PCI.

Conclusions: In the highly selected population, PCI for chronic total occlusion, with excimer laser plaque debulking followed by provisional stents, was a safe procedure with a very acceptable rate of new target vessel revascularization in the follow-up period.

Lasers Surg Med. 2000;26(5):425-31Coronary revascularization in heart transplant recipients by excimer laser angioplastyTopaz O, Janin Y, Bernardo N, Bailey NT, Mohanty PK

Interventional Cardiovascular Laboratories, McGuire VA Medical Center, Divisionof Cardiology, Medical College of Virginia/Virginia Commonwealth University,Richmond, Virginia 23249, USA.

Background And Objective: Aggressive development of allograft coronary artery disease is a major cause of death in heart transplant recipients. Percutaneous balloon angioplasty is considered suboptimal for complex lesions in native coronary vessels and heart transplant recipients, alike. Excimer laser energy (308-nm wavelength) can successfully remove and vaporize atherosclerotic plaques in native coronary vessels; however, its application in heart transplant recipients has not been studied clinically yet.

Study Design/Materials And Methods: Six heart transplant recipients underwent percutaneous excimer laser (CVX-300, Spectranetics, Colorado Springs, CO) coronary angioplasty for treatment of a total of 10 discrete, obstructive coronary artery lesions. By using concentric or eccentric multifiber laser catheters, energy parameters were set at a fluence of 45 mJ/mm(2) or 60 mJ/mm(2) with a frequency of 25 Hz and 40 Hz, respectively, with a pulse duration of 135 ns and output of 200 mJ/pulse. The "saline flush" and "pulse and retreat" lasing techniques were used. In each case, adjunct balloon angioplasty was performed; in five lesions, an intracoronary stent was implanted. Angiographic evaluation was performed by visual assessment.

Results: Each procedure was successful as defined by laser recanalization of the target lesion (reduction of target lesion stenosis in more than 20%) and subsequent adequate final luminal patency (reduction of target lesion stenosis to less than 50%) and absence of any major in-cardiac catheterization complication (such as perforation, acute closure, dissection, emergency coronary artery bypass surgery), or in-hospital complications (such as death, myocardial infarction, cardiac enzyme elevation, major bleeding), or need for surgical revascularization. A 92 +/- 5% preprocedural percent diameter stenosis was reduced by laser to 35 +/- 16% and by adjunct balloon angioplasty in all lesions and stenting in five lesions, to final residual stenosis of 2 +/- 6%. Angiographic follow-up between 2 and 6 months after the procedure demonstrated a target lesion restenosis rate of 22%.

Conclusion: Percutaneous excimer laser is safe and efficacious in the treatment of focal obstructive lesions caused by allograft coronary artery disease. These data represent an early clinical experience; thus, the long-term outcome of this revascularization method in recipients of heart transplantation will have to be determined by a large scale prospective, randomized, multicenter clinical study.

Br J Surg. 1999 Oct;86(10):1258-63Clinical study of adjuvant photodynamic therapy to reduce restenosis following femoral angioplastyJenkins MP, Buonaccorsi GA, Raphael M, Nyamekye I, McEwan JR, Bown SG, Bishop CC.

Vascular Unit and National Medical Laser Centre, Department of Surgery,University College London, Middlesex Hospital, London, UK.

Background: Photodynamic therapy (PDT) reduces neointimal hyperplasia and negative remodelling following balloon injury in small and large animal models. This clinical study investigated the role of adjuvant PDT following femoral percutaneous transluminal angioplasty (PTA).

Methods: Eight PTAs in seven patients (two women) with a median age of 70 (range 59-86) years were performed with adjuvant PDT. All patients had previously undergone conventional angioplasty at the same site which resulted in symptomatic restenosis or occlusion between 2 and 6 months. Each was sensitized with oral 5-aminolaevulinic acid 60 mg/kg, 5-7 h before the procedure. Following a second femoral angioplasty, up to 50 J/cm2 red light (635 nm) was delivered to the angioplasty site via a laser fibre within the angioplasty balloon. Patients were kept in subdued light overnight and discharged the following day. Outcome was assessed by duplex imaging at 24 h, 1, 3 and 6 months and by intravenous digital subtraction angiography at 6 months. A peak systolic velocity ratio (PSVR) of more than 2.0 at the angioplasty site was taken to represent restenosis.

Results: All patients tolerated the procedure well without adverse complications or death. All were rendered asymptomatic which was sustained throughout the study interval. All vessels remained patent and no lesion attained the duplex definition of restenosis. Median (interquartile range) PSVR across stenotic segments was 4.7 (3.7-5.7) before angioplasty, 1.1 (0.9-1.3) at 24 h and 1.4 (1.0-1.8) at 6 months after intervention (P = 0.04 compared with preoperative value).

Conclusion: This pilot study suggests that endovascular PDT is safe and may reduce restenosis follow- ing angioplasty. The data justify a randomized controlled trial.

Kobe J Med Sci. 1999 Aug;45(3-4):137-48Evaluation of local platelet deposition during laser thermal angioplastyNakagiri K, Okada M, Tsuji Y, Yoshida M, Yamashita T

Department of Surgery, Kobe University School of Medicine

Laser thermal angioplasty is one of the brand-new transluminal interventions for arterial occlusive disease. And one of the most important prognostic factors of this intervention is the degree of local platelet deposition which causes the acute platelet thrombus and increases the proliferation of smooth muscle cells. The purpose of this study is to assess the degree of platelet deposition on the laser ablated area and to investigate the optimal conditions of laser ablation from the point of thrombogenesis. First of all, the laser ablations of various delivered energy were carried out on canine femoral arteries, then thrombus formation after laser ablation was evaluated with angioscopy. No thrombus was recognized on all ablated areas in the cases with a laser energy of 16 Joule (J) and 20 J. On the other hand, small thrombus on the ablated area was observed in 1 of 4 cases (25%) with that of 24 J, and in 2 of 4 cases (50%) with that of 30 J. Then, the degree of platelet deposition on the laser ablated area was evaluated with platelet labeled radioimmunoassay. Laser ablations were employed in canine femoral arteries varying delivered laser energy. There were no differences in the numbers of platelet deposition when the laser energy for one shot was within 24 J. The numbers of platelet deposition with a laser energy of 30 J and 45 J were significantly (p < 0.05) higher than those with a laser energy within 24 J. The numbers of platelet deposition were gradually increased related to the frequency of laser ablations, and the numbers of platelet depositions in 10 repeated laser ablations of 16 J and 20 J were significantly (p < 0.05) higher than that in single laser ablation of 16 J and 20 J. From the aspect of local platelet deposition, the optimal laser energy for one shot should be restricted within 24 J and the repeated ablation was the most appropriate method of laser thermal ablation.

Arq Bras Cardiol. 1999 Aug;73(2):149-56In-stent restenosis. Acute and long-term outcomes after excimer laser coronary angioplasty.Bejarano J, Bermudez E, Diaz P, Gallarello F, Margolis JR

Miami Heart Institute and Medical Center, Florida 33140, USA

Objective: With the increased use of intracoronary stents, in-stent restenosis has become a clinically significant drawback in invasive cardiology. We retrospectively assessed the short- and long-term outcomes after excimer laser coronary angioplasty of in-stent restenosis.

Methods: Twenty-five patients with 33 incidents of in-stent restenosis treated with excimer laser coronary angioplasty (ELCA) were analyzed. Sixty-six percent were males, mean age of 73 +/- 11 years, and 83% were functional class III-IV (NYHA). ELCA was performed using 23 concentric and 10 eccentric catheters with a diameter of 1.6-2.2 mm, followed by balloon angioplasty (PTCA) and ultrasound monitoring. The procedure was performed in the following vessels: left anterior descending artery, 10; left circumflex artery, 8; right coronary artery, 6; left main coronary artery, 2; and venous bypass graft, 7.

Results: The ELCA was successful in 71% of the cases, and PTCA was 100% successful. The diameter of the treated vessels was 3.44 +/- 0.5 mm; the minimal luminal diameter (MLD) increased from 0.30 mm pre-ECLA to 1.97 mm post-ELCA, and to 2.94 mm post-PTCA (p < 0.001). The percent stenosis was reduced from 91.4 +/- 9.5% before ECLA to 42.3 +/- 14.9% after ELCA and to 14.6 +/- 9.3% after PTCA (p < 0.001). Seventeen (68%) patients were asymptomatic at 6 months and 15 (60%) at 1 year. New restenosis rates were 8/33 (24.2%) at 6 months and 9/33 (27.3%) at 12 months.

Conclusion: ELCA is safe and effective for the treatment of in-stent restenosis. In the present sample, a slight increase in new restenotic lesions between 6 and 12 months was found.

J Am Coll Cardiol. 1999 Jul;34(1):25-32Laser angioplasty of restenosed coronary stents: results of a multicenter surveillance trial. The Laser Angioplasty of Restenosed Stents (LARS) InvestigatorsKöster R, Hamm CW, Seabra-Gomes R, Herrmann G, Sievert H, Macaya C, Fleck E, Fischer K, Bonnier JJ, Fajadet J, Waigand J, Kuck KH, Henry M, Morice MC, Pizzulli L, Webb-Peploe MM, Buchwald AB, Ekström L, Grube E, Al Kasab S, Colombo A, Sanati A, Ernst SM, Haude M, Serruys PW, et al

Medical Clinic, Department of Cardiology, University Hospital Eppendorf, Hamburg,Germany

Objectives: This study evaluated safety and efficacy of excimer laser angioplastyfor treatment of restenosed or occluded coronary stents.

Background: Balloon angioplasty of in-stent restenosis is limited by a high recurrence rate. Debulking by laser angioplasty is a novel concept to treat in-stent restenosis.

Methods: A total of 440 patients with restenoses or occlusions in 527 stents were enrolled for treatment with concentric or eccentric laser catheters and adjunctive balloon angioplasty.

Results: Laser angioplasty success (< or =50% diameter stenosis after laser treatment or successful passage with a 2.0-mm or 1.7-mm eccentric laser catheter) was achieved in 92% of patients. Adjunctive balloon angioplasty was performed in 99%. Procedural success (laser angioplasty success followed by < or =30% stenosis with or without balloon angioplasty) was 91%. There was neither a significant difference in success with respect to lesion length, nor were there differences between small and large vessels or native vessels and vein grafts. Success was higher and residual stenosis lower using large or eccentric catheters. Serious adverse events included death (1.6%, not directly laser catheter related), Q-wave myocardial infarction (0.5%), non-Q-wave infarction (2.7%), cardiac tamponade (0.5%) and stent damage (0.5%). Perforations after laser treatment occurred in 0.9% of patients and after balloon angioplasty in 0.2%. Dissections were visible in 4.8% of patients after laser treatment and in 9.3% after balloon angioplasty. Reinterventions during hospitalization were necessary in 0.9% of patients; bypass surgery was performed in 0.2%.

Conclusions: Excimer laser angioplasty with adjunctive balloon angioplasty is a safe and efficient technology to treat in-stent restenoses. These data justify a randomized comparison with balloon angioplasty.

Rofo. 1999 Jan;170(1):105-8PTLA (percutaneous transluminal laser angioplasty) recanalization of femoral artery stenoses/occlusions after Angio-Seal administrationSteinkamp HJ, Scheinert D, Hettwer H, Haufe M, Kenzel P, Biamino G, Felix R

Strahlenklinik und Poliklinik, Universitätsklinikum Charité Campus Virchow, Humboldt Universität Berlin. Purpose : To demonstrate desobliration of Angio-Seal-induced femoral artery stenosis and occlusion by Excimer-laser assisted angioplasty and PTA.

Patients and methods: The Angio-Seal hemostatic closure device was applied to the puncture site in 1500 patients after diagnostic or therapeutic coronary artery catheterisation. In 5 of 1500 cases symptoms of claudication occurred. Following the determination of the walking distance and ankle-brachial systolic pressure index (ABI) and diagnostic angiography, therapeutic percutaneous transluminal laser angioplasty (PTLA) and PTA was performed.

Results: 5 patients with acute symptoms of peripheral artery disease presented with superficial femoral artery occlusions (three cases) and high grade stenoses of the common femoral arteries (two cases). Angiographic and clinical improvement was achieved after PTLA/PTA in all five patients. The mean walking distance increased from 61 meters to 600 meters. The average ankle-brachial systolic pressure index increased from 0.40 to 0.82.

Conclusions: PTLA/PTA is a satisfactory therapeutic method for femoral artery occlusion or high-grade stenosis following Angio-Seal application.

Neurol Res. 1999 Jan;21(1):84-8A new system for a combined laser and ultrasound application in neurosurgeryDesinger K, Liebold K, Helfmann J, Stein T, Müller G

Laser- und Medizin Technologie gGmbH, Berlin, Germany

A new combined Laser and Ultrasound Surgical Therapy (LUST) device suitable for endoscopical coagulation and tissue fragmentation has been developed at the LMTB. The new feature is the simultaneous transmission of laser radiation and ultrasound via flexible silica glass fibers. The ultrasound tissue interaction is based on the well-known CUSA-technology which enables the surgeon to cut various types of tissue with different degrees of effectiveness. Application fields are in oncology, neurosurgery and angioplasty. The laser radiation can be used, for example, for tissue coagulation purposes. With a fiber based LUST-system working at a frequency of 30 kHz, a displacement of 100 microns could be attained at the distal end. (The usual standard CUSA displacement is 10-350 microns.) During in vitro experiments the following tissue fragmentation rates could be achieved: brain tissue 50 mg sec-1, liver 4.5 mg sec-1 and kidney 4 mg sec-1 (displacement of the tip 60 microns; phi 1.3 mm; suction setting: 5 W). Laser radiation up to 25 W was sufficient to coagulate soft tissue. This technology offers new possibilities in minimal invasive surgery. The flexible opto-acoustic waveguide (phi 400-1700 microns) can be bent making areas accessible that were previously inaccessible. Without changing the instrumentation the surgeon can use the laser radiation for tissue coagulation or cutting and the ultrasound for tissue fragmentation and tissue reduction.

Rofo. 1998 Nov;169(5):537-41Stability of iodinated contrast media in UV-laser irradiation and toxicity of the photoproductsGrönewäller EF, Wahl HG, Kehlbach R, Rodemann HP, Claussen CD, Duda SH

Abteilung Radiologische Diagnostik, Radiologische Universitätsklinik Tübingeneckart.gronewaller@t-online.de

Purpose: In XeCl-Excimer laser angioplasty, unintended and possibly harmful interaction of the UV-laser light and the contrast media may occur due to the high concentration of contrast medium proximal to the occlusion or subtotal stenosis.

Methods: One ml of three nonionic monomeric contrast agents (iopromide, iomeprol, iopamidol), one nonionic dimeric (jotrolane), and one ionic monomeric (amidotrizoate) X-ray contrast agent were irradiated with a XeCl excimer laser (lambda = 308 nm, pulse duration 120 ns, 50 Hz) using a 9 French multifiber catheter (12 sectors). Up to 20,000 pulses (106 J) were applied. Using high performance liquid chromatography the amount of liberated iodide as well as the fraction of unchanged contrast media were measured. Cytotoxicity of the photoproducts was tested in a colony formation assay of human skin fibroblasts. The contrast agents were irradiated with 2000 pulses/ml (5.3 mJ/pulse; 10.6 J) and then added to the cell cultures for a period of three hours in a concentration of 10%.

Results: Excimer laser irradiation induced iodide liberation of up to 3.3 mg iodide/ml. Up to 19% of the contrast agents changed their original molecular structure. Incubation of irradiated contrast agents resulted in a significantly decreased potential for colony formation (p values ranging from 0.0044 to 0.0102) with significantly higher toxicity of amidotrizoate and iomeprol in comparison to iopromide, iotrolan, and iopamidol.

Discussion: Due to the cytotoxic photoproducts and the high level of liberated iodide, it is recommended to flush the artery with physiological saline solution before applying a pulsed excimer laser in human arterial obstructions in order to reduce the contrast agent concentration at the site of irradiation.

J Clin Laser Med Surg. 1998 Oct;16(5):249-54Clinical experience of endovascular laser intervention in cardiovascular diseaseOkada M, Yoshida M, Tsuji Y

Department of Surgery, Kobe University School of Medicine, Japan

Objective: The authors studies laser angioplasty for patients with obstructivearterial diseases since the 1980s.

Summary Background Data: Usefulness of laser angioplasty for endovascular surgery was recognized especially for patients having short segments of severe atherosclerotic changes in vessels.

Methods: The authors retrospectively reviewed clinical experience of angioplasty by argon laser for 113 patients (103 peripheral, 10 coronary artery). Using an argon laser optimal conditions were (a) 6W in output and 3 sec in irradiation time or (b) metal tip temperature of 200 degrees C and 5 sec of ablation time for the peripheral artery. On the other hand, 4-5 W in output and 2 sec in irradiation time were optimal conditions for the same procedure on the coronary artery.

Results: The initial success rate of laser angioplasty for the peripheral artery was 92% in the stenotic lesions and 73% in the occlusive lesions. However, cumulative patency rate was 85% in the stenotic lesions and 74% in the occlusive lesions in the long-term follow-up study of 106 months among the patients with clinical success. On the basis of the excellent results in the peripheral arterial diseases, coronary laser angioplasty and coronary artery bypass grafting was intraoperatively performed in 10 patients with anginal attack. Patency ratewas 90% in this series.

Conclusions: Laser angioplasty for endovascular surgery was a useful procedure for patients with stenotic and occlusive changes of the peripheral and coronary arteries. Consequently, this method should be recommended especially for high-risk patients with atherosclerosis.

Z Kardiol. 1998 Jul;87(7):537-44.Acute results of ablation of coronary in-stent restenoses with eccentric excimer laser cathetersKöster R, Hamm CW, Terres W, Koschyk DH, Reimers J, Kähler J, Meinertz T

Universitäts-Krankenhaus Eppendorf Medizinische Klinik, Abteilung Kardiologie, Hamburg

Laser catheters which run eccentrically on a guide wire were developed for maximization of luminal gain by excimer laser angioplasty (ELCA). We investigated the safety and efficacy of ELCA with these new catheters plus PTCA in patients with restenoses or occlusions in coronary stents. ELCA was performed in 57 patients (60 +/- 9 years) with stenoses in 75 stents (35 AVE Micro stents, 26 Palmaz-Schatz stents, 7 NIR stents, 7 other stents). In 44 patients eccentric 1.7 mm catheters and in 13 patients 2.0 mm catheters were used. The success of the intervention was analyzed by intravascular ultrasound (IVUS) in a subgroup of 7 patients treated with five 1.7 mm and two 2.0 mm catheters. The laser catheters could be advanced through the in-stent restenoses in 56 patients. A passage inhibition occurred in one patient with an inadequately expanded stent < 2.0 mm in diameter. ELCA reduced the diameter stenoses from 77 +/- 10% before intervention to 44 +/- 8% after treatment with the 1.7 mm catheter (n = 43) or to 34 +/- 9% after passages with the 2.0 mm catheter (P < 0.001). PTCA further reduced the diameter stenosis to 11 +/- 12% (P < 0.001). The IVUS analysis revealed a smooth ablation profile in all patients. In 4 patients creatine kinase elevations > or = 2 times normal value occurred. There was no evidence of a Q-wave infarction. No dissections were observed within the stents. Outside of the stents there were dissections in 5 vessels, which required the implantation of additional stents. CONCLUSIONS: ELCA with eccentric laser catheters for treatment of in-stent restenosis is safe and effective. The incidence of complications is acceptable.

Cathet Cardiovasc Diagn. 1998 Jun;44(2):235-43Laser wire for crossing chronic total occlusions: "learning phase" results from the U.S. TOTAL trial. Total Occlusion Trial With Angioplasty by Using a Laser Wire

Oesterle SN, Bittl JA, Leon MB, Hamburger J, Tcheng JE, Litvack F, Margolis J, Gilmore P, Madsen R, Holmes D, Moses J, Cohen H, King S 3rd, Brinker J, Hale T, Geraci DJ, Kerker WJ, Popma J

Department of Medicine, Stanford University Medical Center, California 94305,USA. steve_oesterle@cvmed.stanford.edu

The Prima laser guidewire system (Spectranectics Corp., Colorado Springs, CO) consists of an 0.018" hypotube containing a bundle of 45-microm optical fibers coupled to a pulsed excimer laser operating at a tip fluence of 60 ml/mm2 and a repetition rate ranging from 25-40 Hz. This laser guidewire was specifically designed to cross total occlusions refractory to passage with conventional wires. The Prima wire was evaluated in a feasibility study at 15 U.S. centers. Following failure to cross a total occlusion with approved guidewires, the Prima wire was utilized in 179 patients. Average age of subjects was 61 yr. Lesion locations included left anterior descending (36%), right (45%), and circumflex (19%) coronary arteries. Mean angiographic age of total occlusions was 70 wk (range, 2-1,020 wk, median, 14 wk). The use of the Prima wire either solely or in combination with conventional guidewires resulted in successful crossing in 61% of these previously impenetrable occlusions. Failure of the device was commonly related to length of the occlusion and tortuosity along the occluded pathway. Major complications included myocardial infarction in 7 patients (3.9%), tamponade in 3 (1.7%), and death in 2 (1.1%). This "learning phase" pilot study confirmed the feasibility of a laser guidewire in chronic total occlusions that are resistant to passage of conventional guidewires. An extended registry at these investigative sites is planned.

J Heart Lung Transplant. 1998 May;17(5):505-10Application of solid-state pulsed-wave, mid-infrared laser for percutaneous revascularization in heart transplant recipientsTopaz O, Bailey NT, Mohanty PK

Division of Cardiology, McGuire VA Medical Center, Medical College of Virginia,Virginia Commonwealth University, Richmond 23249, USA.

Background: Severe allograft coronary artery disease is a significant cause of death in heart transplant recipients. Percutaneous revascularization has thus far been attempted with balloon angioplasty and, to a lesser extent, with directional atherectomy. The new, investigational, solid-state pulsed-wave mid-infrared laser (holmium:YAG) can vaporize and remove atheromatous and thrombotic plaques. This mechanism of plaque ablation may be useful for allograft coronary artery disease associated with focal stenoses deemed unsuitable for standard balloon angioplasty, especially thrombus-containing lesions.

Methods: Five adult heart transplant recipients with severe focal stenoses related to allograft coronary artery disease underwent six laser angioplasty procedures. Laser catheters (2.1 microm, 250 to 600 mJ, 5 Hz) varying from 1.2 mm to 2.0 mm delivered 45 +/- 7.4 pulses (mean +/- SD). Five laser procedures were completed with adjunct balloon angioplasty and one with directional atherectomy.

Results: Laser success (defined as stenosis reduction > 20%, no cardiac catheterization laboratory or in-hospital major complication) was achieved in six of seven lesions (85%), and the overall (laser and adjunct balloon) procedural success rate was 100%. No major complications occurred. Laser-assisted angioplasty reduced mean stenosis from 90% +/- 3% to 9% +/- 11%. All five patients recovered and were discharged. Angiographic follow-up demonstrated a 50% restenosis rate.

Conclusions: In selected heart transplant recipients laser-assisted angioplasty can provide safe and successful acute revascularization. Focal lesions considered "nonideal" for balloon angioplasty and, in particular, thrombotic lesions can benefit from application of this device; however, long-term reduction of restenosis rates is not expected from this modality.

J Cardiovasc Surg (Torino). 1998 Apr;39(2):131-5Nd Yag laser angioplasty: a safe procedure in peripheral vascular surgeryNazzal M, Kaidi A, Thanh P

Department of Surgery, University of Iowa Hospital and Clinical, Iowa City 52242,

USA

Background: Thirty-three patients (34 limbs) with peripheral vascular occlusive disease were treated with Nd Yag laser assisted angioplasty over a three-year period (1989-1991).

Methods: Sixteen males and 17 females were included in the study. The mean age of all patients was 70.29 (44-86) years. Twenty-two (66.7%) patients were smokers, 21 (63.6%) had coronary artery disease and 14 (42.4%) had diabetes mellitus. Thirty-three patients (100%) had disabling intermittent claudication, 20 patients (60.6%) had rest pain, 2 patients (6.1%) had ulcers and 10 patients (30.3%) had gangrenous changes. Thirty-nine vessels were treated; 34 (87.2%) superficial femoral arteries, 4 (10.3%) popliteal arteries and 1 external iliac artery. Eleven (28.2%) vessels were totally occluded and the remaining 28 (71.8%) vessels had high grade stenosis of more than 90%. The mean preoperative ABI Index was0.23+/-12.

Results: The preoperative angiogram showed poor out-flow in 24 (70.6%) extremities, 1 patent distal vessel in 7 extremities (20.6%) and at least 2 vessels in 3 extremities (8.8%). The patients were followed up for a period of 9.9 months (20 days-30 months). The procedure could not be done in 2 extremities. All the remaining 32 extremities had patent vessels at the end of the procedure. Fifteen (48.4%) patients stated that they improved but remained symptomatic. Twelve (38.7%) were completely asymptomatic, 3 (9.7%) patients had no change in their symptoms and 2 patients worsened at the end of the follow-up period. The mean postoperative ABI was 0.78. Bleeding from the puncture site requiring closure was the most common complication of the procedure in 6 patients (19.4%). Angioplasty in 5 of these patients was done by the open technique. Other complications included hematoma in 3 (9.7%) patients and one case (3%) of artery perforation. Among those who remained asymptomatic at the end of the follow-up period the mean change in ABI was 0.625+/-0.19, those who improved but remained symptomatic the mean ABI change was 0.43+/-0.25 while those whose symptoms did not change or worsened the mean ABI change was 0.12+/-0.13. The ABI change in the first two groups was significantly higher than the last one (p<0.006 and p<0.001 respectively). There was no significant difference in the outcome of LABA between stenosed and occluded vessels. Smoking was significantly higher in the symptomatic patients (7/20) compared to those who were asymptomatic 5/12, p<0.02. Diabetes mellitus, cardiovascular disease and the preoperative ABI were not significant variables in the outcome of angioplasty.

Conclusions: In conclusion, Nd Yag laser assisted angioplasty is a safe procedure. It could relieve symptoms in 87.1% of cases. Change in the ABI and smoking are predictive of the success of the procedure.

J Invasive Cardiol. 1998 Apr;10(3):162-168Patient-Related and Angiographic Predictors of Restenosis After Excimer Laser Coronary AngioplastyBrito FS Jr, Caixeta AM, Rati MA, Perin MA, Martinez Filho EE, Ramires JA

Rua Oscar Freire 1234, apto. 101, Jd. America, CEP: 01426-000, Sao Paulo, SP,Brazil. fsbrito@usp.br

Excimer laser coronary angioplasty (ELCA) is a useful technique for the treatment of selected complex coronary lesions. However, this technology has been limited by significant restenosis and, to date, predictors of restenosis after use of this device are not clearly defined. In order to determine predictors of restenosis after ELCA, 43 lesions presenting with restenosis (> 50% diameter stenosis) at angiographic follow-up were compared to 46 lesions without restenosis, based on patient-related, qualitative and quantitative angiographic parameters. Univariate analysis revealed 9 variables with at least a borderline (p < 0.15) significant relation to restenosis: (1) age (p = 0.0759), (2) proximal left anterior descending site (p = 0.074), (3) presence of a restenotic lesion (p = 0.104), (4) lesion length (p = 0.0034), (5) reference diameter of the treated vessel (p = 0.0076), (6) post laser minimal luminal diameter (MLD) (p = 0.1160), (7) post-procedural MLD (p = 0.0001), (8) post-procedural stenosis (p = 0.0250) and (9) total procedural gain (p = 0.0051). After entering stepwise logistic regression analysis, only 3 variables emerged as independent predictors ofrestenosis: treatment of a restenotic lesion (p = 0.0255), lesion length (p = 0.0291) and post procedural MLD (p = 0.0007). Based on these data, we conclude that post-procedural MLD is the most important predictor of restenosis after ELCA. Lesion length and the treatment of restenotic lesions are also independently associated with an increased risk of restenosis after ELCA. Therefore, achieving the best possible luminal result at the time of the first intervention should be the goal of the procedure, especially when treating high restenosis risk lesions.

J Laser Appl. 1998 Feb;10(1):34-40Excimer laser spectroscopy: influence of tissue ablation on vessel wall fluorescenceStrebel RT, Utzinger U, Peltola M, Schneider J, Niederer PF, Hess OM

Department of Internal Medicine, University and Swiss Federal Institute ofTechnology, University Hospital, Zurich, Switzerland

Limited steerability and injury to the normal vessel wall are major drawbacks of laser coronary angioplasty. To overcome these limitations a new generation of laser systems has been developed which allows not only to eliminate the atherosclerotic plaque but to guide the laser beam by analyzing the laser induced tissue fluorescence (= spectroscopy) for the treatment of the atherosclerotic vessel. An excimer laser (MAX 10 LP, 308 nm, Technolas, Munich, Germany) was used with an emitting (phi 1070 microns) and a detecting (phi 130 microns) optical fiber to induce tissue fluorescence which was analyzed quantitatively by a computerized system. Specimens from the descending (thoracic) aorta were obtained from 24 patients (mean age 68.1 years, range 44-92). Tissue fluorescence was induced with ablating (26-30 mJ/mm2) and nonablating (3 mJ/cm2) laser activations. The emitted fluorescence (range 380-575 nm) was normalized to a wavelength of 380 nm; as a measure of tissue fluorescence the intensity ratio at 500 nm divided by 400 nm was calculated in normal (n = 78), mildly atherosclerotic (n = 40), and severely atherosclerotic (n = 48) tissue samples. Repeated laser activations were carried out and tissue fluorescence was checked until the fluorescence spectrum was normalized. All tissue samples were analyzed histologically by a semiquantitative score. Normal tissue samples showed the highest intensity ratios (5.9 +/- 3.4), whereas mildly (2.9 +/- 1.3) and severely atherosclerotic (2.1 +/- 1.0) samples elicited a significantly reduced fluorescence. Repeated tissue ablations were associated with a normalization of fluorescence intensity ratios in the mildly (7.0) as well as in the severely diseased (4.9) vessels. A curvilinear relationship between intensity ratio and the semiquantitative score was observed (r = 0.66) as well as between intensity ratio and intimal wall thickness (r = 0.62). No gender related differences were found but there was an inverse relationship between fluorescence intensity ratio and age (r = 0.56) as well as between intimal thickness and age (r = 0.41). Excimer laser spectroscopy allows reliable detection of atherosclerotic vessel alterations. Fluorescence intensity ratio is inversely proportional to the intimal wall thickness and the severity of the histologic alterations. There is an age dependency of fluorescence intensity ratio which can be explained by an increase in intimal wall thickness. Successful tissue ablation can be obtained by laser angioplasty and allows determination of the optimal point where complete tissue ablation is achieved by laser activation. Thus, excimer laser spectroscopy is an effective method for selective tissue ablation by laser angioplasty.

Angiology. 1998 Feb;49(2):91-8Percutaneous excimer laser angioplasty of lower limb vessels: results of a prospective 24-month follow-upVisonà A, Perissinotto C, Lusiani L, Bonanome A, Pesavento R, Miserocchi L, Liessi G, Pagnan A

Department of Internal Medicine, University of Padua, Italy

The aim of this prospective study was to assess the effectiveness and the long-term patency effect of excimer laser angioplasty in peripheral arterial obstructive disease. Seventy-eight patients referred for excimer laser angioplasty of lower limbs have been followed up for up to 24 months. Ankle/brachial systolic pressure index, color Doppler mapping, and arterial digital subtraction angiography were performed. Immediate procedural success was achieved in a high percentage of patients (97%). Balloon angioplasty was also used in 85% of patients. Early reocclusions occurred in 8% of patients. The cumulative patency rate was 47% at the 12 month interval and 40% at the 24-month interval. Poor runoff and the length of the lesions negatively influenced the outcome. Excimer laser angioplasty is an effective procedure, indicated in selected patients showing < 10 cm occlusions and good runoff.

Heart. 1998 Jan;79(1):34-8Clinical events following excimer laser angioplasty or balloon angioplasty for complex coronary lesions: subanalysis of a randomised trialAppelman YE, Piek JJ, Redekop WK, de Feyter PJ, Koolen JJ, David GK, StrikwerdaS, Tijssen JG, Serruys PW, van Swijndregt E, van Gemert MJ, Lie KI

Department of Cardiology, University of Amsterdam, Netherlands

Objectives: To compare clinical outcome in patients with complex coronary lesions treated with either excimer laser coronary angioplasty (ELCA) or balloon angioplasty.

Patients And Design: 308 patients with stable angina and a coronary lesion of more than 10 mm in length were randomised to ELCA (151 patients, 158 lesions) or balloon angioplasty (157 patients, 167 lesions). The primary clinical end points were death, myocardial infarction, coronary bypass surgery, or repeated coronary angioplasty of the randomised segment during six months of follow up. Subanalysis was performed to identify a subgroup of patients with a beneficial clinical outcome following ELCA or balloon angioplasty.

Setting: Two university hospitals and one general hospital.

Results: There were no deaths. Myocardial infarction, coronary bypass surgery, and repeated angioplasty occurred in 4.6, 10.6, and 21.2%, respectively, of patients treated with ELCA compared with 5.7, 10.8, and 18.5%, respectively, of those treated with balloon angioplasty. ELCA did not yield a favourable clinical outcome in subgroups of patients with long (more than 20 mm) coronary lesions, calcified lesions, small diseased vessels (< or = 2.5 mm reference diameter), or total coronary occlusions. There was a worse clinical outcome in patients with tandem lesions treated with ELCA compared with balloon angioplasty (9/18 v 3/26 lesions; p = 0.01); while a trend towards an unfavourable clinical outcome was found in patients with vessels with a reference diameter of more than 2.5 mm (23/66 v 13/63 lesions, p = 0.07) and left circumflex coronary lesions (12/41 v 6/42 lesions, p = 0.08).

Conclusions: The findings indicate a worse clinical outcome in patients with lesions of more than 10 mm treated with ELCA compared with balloon angioplasty who have tandem coronary lesions and in those with vessels with a reference diameter of more than 2.5 mm and left circumflex coronary lesions.

Lasers Surg Med. 1998;23(5):281-90Psoralen and long wavelength ultraviolet radiation as an adjuvant therapy for prevention of intimal hyperplasia and constrictive remodeling after balloondilation: a study in the rabbit iliac arteryPerrée J, van Leeuwen TG, Velema E, Borst C

Department of Cardiology, Heart-Lung Institute, Utrecht University Hospital, The Netherlands.

Background And Objective: Restenosis after balloon angioplasty is the summated effect of intimal hyperplasia and arterial shrinkage, both caused by hyperproliferation. In the present study, the potential of a photochemotherapeutic modality (Psoralen + UVA: PUVA) for the prevention of angioplasty induced proliferation was explored.

Study Design/Materials And Methods: In rabbit iliac arteries, balloon dilation followed by PUVA-therapy (H = 1 J/cm2) was performed (n = 15). Contralateral arteries served as control. After 2 and 28 days of survival, the contribution of intimal hyperplasia and remodeling to lumen loss was determined by means of angiography and histological analysis.

Results: After 2 days, large parts of the media had become acellular, while proliferation was occurring predominantly in the adventitia in both groups. After 28 days, late loss, arterial shrinkage, but not intimal hyperplasia were larger in the PUVA group (P < 0.05).

Conclusion: PUVA-therapy did not prevent intimal hyperplasia following balloon dilation but enhanced luminal narrowing by augmented constrictive remodeling.

Lasers Surg Med. 1998;23(3):128-40Saline flush during excimer laser angioplasty: short and long term effects in the rabbit femoral arteryvan Leeuwen TG, Velema E, Pasterkamp G, Post MJ, Borst C

Interuniversity Cardiology Institute of The Netherlands, Utrecht T.vanLeeuwen@excar.gdl.ruu.nl

Background And Objective: In this study, the effect of flushing saline on arterial wall damage (medial ruptures and necrosis), intimal hyperplasia, and arterial remodeling was determined. During excimer laser coronary angioplasty saline is flushed to reduce the size of explosive water vapor bubbles formed by intraluminal delivery of excimer laser pulses in blood.

Methods: In the femoral artery of the rabbit, 600 excimer laser pulses (308 nm, 50 mJ/mm2 per pulse, 20 Hz) were delivered coaxially over a length of 20 mm in 10 bursts of 3 seconds each. In 24/48 procedures, saline was flushed (0.2 ml/s) via the guidewire channel. After 2 and 56 days, microscopic and angiographic results were compared.

Results: At 2 days, as compared to lasing in blood, saline flush had drastically reduced the incidence of dissections (2/12 vs. 11/12, P < 0.002), but had increased the extent of medial and adventitial necrosis. The latter is attributed to direct irradiation of the arterial wall. After 56 days, in the saline group, in the middle-distal part of treated segments, medial necrosis without intimal hyperplasia was observed. However, at the edges of these lesions, intimal hyperplasia and arterial shrinkage reduced the lumen.

Conclusion: Flushing saline during coaxial excimer laser pulse delivery significantly reduced the incidence of vessel wall ruptures, and prevented intimal hyperplasia formation in part of the lesion. The histologic findings at 56 days are attributed to the optical window which the saline flush provides for direct ultraviolet light irradiation of the arterial wall.

Lasers Surg Med. 1998;22(4):228-39Acute results, complications, and effect of lesion characteristics on outcome with the solid-state, pulsed-wave, mid-infrared laser angioplasty system: final multicenter registry report.Holmium:YAG Laser Multicenter InvestigatorsTopaz O, McIvor M, Stone GW, Krucoff MW, Perin EC, Foschi AE, Sutton J, Nair R, deMarchena E

Division of Cardiology, McGuire VA Medical Center, Medical College of VirginiaHospitals, Medical College of Virginia, Richmond 23249, USA

Background And Objective: The solid-state, mid-infrared holmium:YAG laser (2.1 microm wavelength) is a relatively new percutaneous device that has recently been evaluated in a multicenter study. Because of its unique wavelength and photoacoustic effects on atherosclerotic plaques, this laser may be useful in treatment of symptomatic patients with coronary artery disease. This study sought to evaluate the safety and efficacy of mid-infrared laser angioplasty in the treatment of coronary artery lesions.

Patients And Methods: Laser angioplasty was performed on 2,038 atherosclerotic lesions in 1,862 consecutive patients with a mean age of 61 +/- 11 years. Clinical indications included unstable angina (69%), stable angina (20%), acute infarction (6%), and positive exercise test (5%). Complex lesion morphology included eccentricity (62%), thrombus (30%), total occlusion (27%), long lesions (14%), and saphenous vein grafts (11%).

Results: This laser catheter alone successfully reduced stenosis (>20%) in 87% of lesions. With adjunct balloon angioplasty, 93% procedural success was achieved. The presence of thrombus within the target lesion was a predictor of procedural success (OR = 2.0 [95% confidence interval 2.0, 4.0], P = .04). Bifurcation lesions (OR = 0.5 [95% confidence interval 0.2, 1.0], P = .05) and severe tortuosity of the treated vessel (OR = 0.4 [95% confidence interval 0.2, 0.9], P = .02) were identified as significant predictors of decreased laser success. Calcium within the lesion was associated with reduced procedural success (OR = 0.57 [95% confidence interval 0.34, 0.97], P = .03), and calcified lesions required significantly more energy pulses than noncalcified lesions (119 +/- 91 pulses vs. 101 +/- 86 pulses, respectively, P = .0002). Complications included in-hospital bypass surgery 2.5%, Q-wave myocardial infarction 1.2%, and death 0.8%. Perforation occurred in 2.2% of patients; major dissection in 5.8% of patients, and spasm in 12% of patients. No predictor of major complications was identified. Six-month angiographic restenosis was documented in 54% of patients, and clinical restenosis occurred in 34% of patients.

Conclusion: Mid-infrared laser has a safety profile similar to that of other debulking devices. This laser may be useful in select patients presenting with acute ischemic syndromes associated with intracoronary thrombus; however, like other coronary lasers, it is limited by the need for adjunctive balloon angioplasty and/or stenting to achieve adequate final luminal diameter. No beneficial effects on reducing 6-month restenosis rates were observed.

Lasers Surg Med. 1998;23(5):281-90Psoralen and long wavelength ultraviolet radiation as an adjuvant therapy for prevention of intimal hyperplasia and constrictive remodeling after balloon dilation: a study in the rabbit iliac arteryPerrée J, van Leeuwen TG, Velema E, Borst C

Department of Cardiology, Heart-Lung Institute, Utrecht University Hospital, The Netherlands

Background And Objective: Restenosis after balloon angioplasty is the summate effect of intimal hyperplasia and arterial shrinkage, both caused by hyperproliferation. In the present study, the potential of a photochemotherapeutic modality (Psoralen + UVA: PUVA) for the prevention of angioplasty induced proliferation was explored.

Study Design/Materials And Methods: In rabbit iliac arteries, balloon dilation followed by PUVA-therapy (H = 1 J/cm2) was performed (n = 15). Contralateral arteries served as control. After 2 and 28 days of survival, the contribution of intimal hyperplasia and remodeling to lumen loss was determined by means of angiography and histological analysis.

Results: After 2 days, large parts of the media had become acellular, while proliferation was occurring predominantly in the adventitia in both groups. After 28 days, late loss, arterial shrinkage, but not intimal hyperplasia were larger in the PUVA group (P < 0.05).

Conclusion: PUVA-therapy did not prevent intimal hyperplasia following balloon dilation but enhanced luminal narrowing by augmented constrictive remodeling.

Am J Cardiol. 1997 Dec 1;80(11):1424-8Treatment of in-stent coronary restenosis by excimer laser angioplastyKöster R, Hamm CW, Terres W, Koschyk DH, Reimers J, Kähler J, Meinertz T

Medical Clinic, Department of Cardiology, University Hospital Eppendorf, Hamburg, Germany

We evaluated the efficacy and safety of excimer laser angioplasty (ELCA) with adjunctive balloon angioplasty in patients with restenotic or occluded coronary stents. ELCA was performed in 70 patients (60 +/- 9 years), who had previously been treated with Micro Stents (n = 65), Palmaz-Schatz (n = 38), Wiktor, NIR, Freedom, and Multi-Link stents (n = 1 each). Restenosis (> or =50% diameter stenosis) was documented in 90 stents, another 17 stents were occluded. Laser energy was delivered to the lesions with catheters 1.4, 1.7 (eccentric), and 2.0 mm in diameter. Procedural success was controlled by intravascular ultrasound in a subgroup. Laser catheters crossed all restenotic or occluded stents and decreased diameter stenosis from 80 +/- 13% to 44 +/- 11% (p <0.001). Adjunctive balloon angioplasty further reduced diameter stenosis to 13 +/- 13% (p <0.001). In 13 patients with 21 stents, serial intravascular ultrasound imaging revealed a reduction of plaque area within the stent by 34 +/- 22% (from 4.2 +/- 1.8 mm2 to 2.7 +/- 1.1 mm2) after ELCA and a reduction by 65 +/- 16% (to 1.5 +/- 0.7 mm2) after balloon angioplasty (p <0.01). There were 4 patients with an increase of creatine kinase levels, 8 patients with major dissections (in 7 patients they were related to adjunctive balloon angioplasty), 1 patient with distal embolization, 2 with minor perforations, and 1 patient with stent dislocation. Reintervention during hospitalization was necessary in 3 patients. ELCA is an efficient and safe technique to debulk tissue in restenotic lesions and total occlusions within stents. The incidence of procedure related complications was low.

Herz. 1997 Dec;22(6):299-307Laser angioplasty and recanalizationHaude M, Welge D, Koch L, Roth T, Ge J, Baumgart D, Erbel R

Abteilung für Kardiologie, Zentrum für Innere Medizin, Universität-GHS Essen.

Percutaneous transluminal coronary balloon angioplasty (PTCA) still is the most frequently applied interventional technique for treatment of coronary artery disease. Plastic deformation of the obstructive plaque with creation of splits, intimal tears and dissections is the main mechanism of PTCA for lumen widening. As a result, acute complications due to flow limiting dissections and acute vessel closure can unpredictably occur resulting in myocardial infarction, urgent bypass surgery and death. Furthermore, long-term success of PTCA is limited by restenosis. In order to overcome these limitations of PTCA, alternative interventional techniques were developed, which instead of deforming the obstructive plaque ablate this

tissue. These techniques include high and low speed rotational angioplasty, directional atherectomy, the transluminal extraction catheter, ultrasound angioplasty and laser (Light Amplification by Stimulated Emission of Radiation) angioplasty. 308 nm XeCl excimer laser angioplasty today is the laser technique of choice for clinical application. This pulsed laser requires direct contact to the obstructive plaque. It creates fast (< 200 microseconds) expanding gas bubbles which induce plaque ablation. Main indications for 308 nm XeCl excimer laser angioplasty are diffuse and long coronary lesions and total coronary occlusions. Despite promising initial results this technique showed no better acute and long-term results in comparison to PTCA for the treatment of these types of lesions ("Amsterdam-Rotterdam" Study, "Excimer Rotational Balloon Angioplasty Comparison" Study). As a result, this interventional technique was rarely applied for patient treatment. More recently, the concept of plaque ablation by 308 nm XeCl excimer laser angioplasty was renewed for the treatment of in-stent restenosis. This indication is being investigated in the "Laser Angioplasty of Restenosed Stents" trial. First results document the practicability and safety of this approach. Long-term results are awaited. With ongoing miniaturization, laser guidewires were developed for the recanalization of chronic total occlusions. The randomized multicenter "Total Occlusion Trial with Angioplasty assisted by Laser guidewire "Study documented a success rate of laser wire recanalization in up to 66% in contrast to 47.5% for mechanical wires only. Long-term results are still awaited. Technical and procedural progress including saline flush during laser application, homogeneous light distribution and the concept of smooth laser ablation is pushed foreward to make excimer laser angioplasty safer, more predictable and more effective.

Rofo. 1997 Dec;167(6):619-26.Value of Doppler blood flow velocity measurements in peripheral percutaneous laser-assisted angioplastiesWellnhofer E, Biamino G, Bernard L, Ragg C, Fleck E

Innere Medizin-Schwerpunkt Kardiologie/Angiologie, Virchow Klinikum und DeutschesHerzzentrum, Humboldt Universität Berlin

Purpose: The aim of the study was to establish the prognostic value and clinical implications of blood flow velocity measurements by Doppler guide wires during peripheral laser-assisted percutaneous transluminal angioplasty (PTLA).

Methods: 39 patients presenting with symptomatic peripheral arterial obstructive disease underwent angiography and blood flow velocity assessment by Doppler guide wire (0.018") prior to and following PTLA. Both quantitative angiography (QCA) for measurement of luminal diameters and Doppler assessment of maximum peak velocities (MPV) were performed 2 cm proximal, over and 2 cm distal to stenoses. The results were compared with the following clinical endpoints: 1. Short-term clinical improvement by AHA-criteria during first follow-up examination and 2. criteria for patency suggested by Rutherford [12] within 1 year (1-22 months).

Results: Angiography demonstrated initial success of PTLA in all patients. Relative diameter stenosis decreased from 70 +/- 0.04% to 17 +/- 0.05%. Mean clinically category improved from 2.7 +/- 0.1 to 1.2 +/- 0.1 following intervention. Mean grade of clinical improvement was 2.8 +/- 0.1. 22/39 patients demonstrated event-free follow-up examinations. Doppler measurements of MPV post PTLA in the proximal reference segment correlated with clinical outcome. MPV > or = 90 cm/s was associated with good primary success, unlimited walking capacity and event-free follow-up. MPV > or = 70 cm/s predicted an improvement of short-term clinical outcome by 2 grades (predictive value 80%). MPV < 70 cm/s was associated with both minor primary clinical improvement (+/- 0, +1) and increased incidence of restenosis during follow-up.

Conclusion: Following PTLA, MPV adds information to angiographic success. MPV > or = 90 cm/s in a proximal reference segment following PTLA predicts good clinical outcome, whereas MPV < 70 cm/s is associated with minor primary clinical success and increased rates of restenosis.

J Am Coll Cardiol. 1997 Dec;30(7):1722-8Short-term results and intermediate-term follow-up of laser wire recanalization of chronic coronary artery occlusions: a single-center experienceSchofer J, Rau T, Schlüter M, Mathey DG

Center for Cardiology Othmarschen, Hamburg, Germany

Objectives: This study sought to elucidate the short-term efficacy and intermediate-term outcome of excimer laser recanalization of chronic coronaryartery occlusions in patients in whom attempts at mechanical revascularization had failed.

Background: Recanalization of chronic coronary occlusions with the use of a mechanical guide wire fails in 30% to 50% of cases, mostly because of inability to pass the wire through the lesion. The value of using excimer laser energy in this setting has not yet been determined.

Methods: The study group comprised 66 consecutive patients with 68 chronic coronary occlusions. Patients were eligible for inclusion in the study if a previous attempt at mechanical revascularization had failed and if their angiographic status was such that 1) the vessel segment distal to the occlusion could be visualized by way of collateral vessels, 2) the entry point of the occlusion was clearly outlined, and 3) not more than one anatomic bend was expected within the occlusion. Excimer laser energy was applied to the lesion through a 0.018-in. (0.046 cm) fiber-optic guide wire. Adjunctive balloon angioplasty and stenting were performed in all successfully treated patients but one.

Results: Thirty-four occlusions (50%) in 32 patients (48%) could be crossed with the laser wire. Location and age of the occlusion had no adverse influence on the outcome of laser wire recanalization, nor did the presence of bridging collateral vessels, a major side branch at the site of the lesion or a blunt stump of the occlusion. An inverse relation was found between the success rate and the length of the occlusion, such that a 19% reduction of the success rate accompanied each 10-mm increment of the mean occlusion length. Thus, the success rate was 68% for lesions < or = 10 mm but only 25% for lesions > 30 to < or = 40 mm. The presence of a bend in the lesion exceeding 60 degrees was strongly related to procedural failure. During a median angiographic follow-up period of 18 weeks, restenosis > 50% (n = 6) or reocclusion (n = 4) was found in 10 of the 32 successfully treated patients, for an intermediate-term success rate of 33% (22 of 66). Clinical follow-up revealed improved anginal status in 21 patients (66%) after a median of 24 weeks. Major complications (death, myocardial infarction, emergency operation) were not encountered.

Conclusions: Successful recanalization of a chronic coronary occlusion by using currently available laser wires can be expected in 50% of selected patients in whom attempts at mechanical revascularization fail. Restenosis or reocclusion accounts for an overall 6-month success rate of 35%.

J Am Coll Cardiol. 1997 Dec;30(7):1714-21Prospective, randomized, multicenter comparison of laser-facilitated balloon angioplasty versus stand-alone balloon angioplasty in patients with obstructive coronary artery disease. The Laser Angioplasty Versus Angioplasty (LAVA) Trial InvestigatorsStone GW, de Marchena E, Dageforde D, Foschi A, Muhlestein JB, McIvor M, Rizik D, Vanderlaan R, McDonnell J

Cardiovascular Institute, El Camino Hospital, Mountain View, California 94040,USA. gstone1418@aol.com

Objectives: The goal of this study was to examine the relative safety and efficacy of laser-facilitated percutaneous transluminal coronary angioplasty (PTCA) versus "stand-alone" PTCA.

Background: Plaque debulking with lasing before PTCA may result in improved lumen dimensions and decreased rates of periprocedural ischemic complications, thus improving short- and long-term outcomes after percutaneous intervention. The mid-infrared holmium:yttrium-aluminum-garnet (YAG) laser has been shown to be effective in a variety of plaque subtypes and may be particularly useful in high risk acute ischemic syndromes.

Methods: A total of 215 patients (mean [+/-SD] age 61 +/- 12 years) with 244 lesions were prospectively randomized at 14 clinical centers to laser versus stand-alone PTCA. After laser treatment, all patients underwent PTCA; 148 patients (69%) had unstable angina.

Results: The procedural success rate without major catheterization laboratory complications was similar in patients assigned to laser treatment or PTCA alone (96.6% vs. 96.9%, p = 0.88), as was the in-hospital clinical success rate (89.7% vs. 93.9%, p = 0.27). There was no difference in postprocedural diameter stenosis after laser treatment compared with PTCA (18.3% +/- 13.6% vs. 19.5% +/- 15.1%, p = 0.50). However, use of the laser, versus PTCA alone, did result in significantly more major and minor procedural complications (18.0% vs. 3.1%, p = 0.0004), myocardial infarctions (4.3% vs. 0%, p = 0.04) and total in-hospital major adverse events (103% vs. 4.1%, p = 0.08). At a mean follow-up time of 11.2 +/- 7.7 months, there were no differences in late or event-free survival in patients assigned to laser treatment versus PTCA alone.

Conclusions: Compared with stand-alone PTCA, laser-facilitated PTCA results in a more complicated hospital course, without immediate or long-term benefits.

Am J Cardiol. 1997 Dec 1;80(11):1419-23Recanalization of total coronary occlusions using a laser guidewire (the European TOTAL Surveillance Study)Hamburger JN, Serruys PW, Scabra-Gomes R, Simon R, Koolen JJ, Fleck E, Mathey D, Sievert H, Rutsch W, Buchwald A, Marco J, Al-Kasab SM, Pizulli L, Hamm C, Corcos T, Reifart N, Hanrath P, Taeymans Y

Department of Coronary Diagnostics and Intervention, Thoraxcentre, AcademicHospital Dijkzigt, Rotterdam, The Netherlands.

The success rates of coronary angioplasty for the treatment of chronic total occlusions are less favorable than for coronary stenosis. Therefore, a new laser guidewire (LW) was designed to facilitate the crossing of chronic total occlusions. We report on the results of a European multicenter surveillance study, evaluating the laser guidewire performance. Between May 1994 and July 1996, 345 patients (age 59 +/- 10 years, 291 men) with chronic total occlusions were enrolled in 28 European centers. The median age of occlusion was 29 weeks (range 2 to 884), the occlusion length 19 +/- 10 mm. LW recanalization was successful in 205 patients (59%/). LW perforation occurred in 73 patients (21%), with hemodynamic consequences in 4 (1%). There were no deaths, emergency coronary artery bypass graft surgery, or Q-wave myocardial infarctions. In a multivariate regression analysis an occlusion age of <40 weeks (p = 0.001, RR = 1.34) and an occlusion length <30 mm (p = 0.01, RR = 1.59) were independent predictors of success. Results indicate that the LW is an effective and safe tool in the treatment of chronic total occlusion refractory to conventional guidewires.

Lasers Med Sci. 1997 Dec;12(4):328-35Smooth excimer laser coronary angioplasty (SELCA) and conventional excimer laser angioplasty: Comparison of vascular injury and smooth muscle cell proliferationOberhoff M, Baumbach A, Herdeg C, Hassenstein S, Xie DY, Blessing E, Hanke H, Haase KK, Betz E, Karsch KR

Department of Medicine, Division of Cardiology, Otfried Müller Str. 10, D-72076, Tübingen, Germany

Although the excimer laser, which utilizes 'non-thermal ablation effects', has achieved encouraging results in early clinical trials, the long-term results have failed to show any advantage over conventional percutaneous transluminal coronary angioplasty (PTCA).A new system, Smooth Excimer Laser Coronary Angioplasty (SELCA), has been developed to reduce the tissue damage in the vessel wall caused by shock waves and vapour bubbles.SELCA (wavelength 308 nm, pulse duration 115 ns, repetition rate 150 Hz and energy density 50 mJ mm(-2)) lowers the amount of shock wave formation and pressure peak amplitude in the surrounding tissue by about eight times when compared to the conventional 308 nm excimer laser (ELCA). In this preclinical evaluation, this new system was compared to ELCA. Fifty New Zealand White rabbits were stimulated by repeated weak DC impulses for a period of 28 days in order to form an atherosclerotic plaque in the right carotid artery. The vessels were excised 3, 7,14 and 28 days after laser irradiation for immunohistochemical analysis.SELCA and ELCA laser treatment lead to a decrease in maximal intimal wall thickness 3 days after intervention

(control: 177+/-4 microm; SELCA: 131+/-22microm; ELCA: 120 +/-33microm). In the period between 3 and 28 days, a moderate increase in intimal wall thickness was observed after SELCA treatment compared to a significant increase after ELCA (28 days after intervention: SELCA: 157+/-22microm; ELCA: 274 +/-28microm). Bromodeoxyuridine (BrdU) was applied 18 and 12 h before excision of the vessels in order to determine the percent of cells undergoing DNA synthesis. The percent of BrdU labelled SMC in the intima (control: 13 +/- 2 cells mm(-2)) increased in both groups after 3 days (SELCA: 248 +/- 107 cells mm(-2); ELCA: 162 +/- 41 cells mm(-2)) and 7 days (SELCA: 162+/- 55 cells mm(-2); ELCA: 279 +/- 119 cells mm(-2)).The present results demonstrate that vascular wall injury and increase in intimal wall thickness following SELCA are reduced in comparison to the results achieved with the conventional technique. Further trials are necessary to assess whether these improvements will lead to more favourable long-term results after excimer laser angioplasty.

Am J Cardiol. 1997 Nov 20;80(10A):99K-105KExcimer laser coronary angioplasty: the New Approaches to Coronary Intervention (NACI) experienceHolmes DR Jr, Mehta S, George CJ, Margolis JR, Leon MB, Isner JM, Bittl JA, King SB 3rd, Siegel RM, Sketch MH, Cowley MJ, Roubin GS, Brinker JA, Overlie PA, Tcheng J, Sanborn TA, Litvack F

The Mayo Clinic, Rochester, Minnesota 55905, USA

In the New Approaches to Coronary Intervention (NACI) registry, 887 patients were electively treated with excimer laser coronary angioplasty (ELCA) for coronary artery disease. The Advanced Interventional System (AIS) system was used in 487 cases; the Spectranetics system, in 400. The mean age was 63.4 years. Most patients had unstable angina (60.3%); 43.7% had a prior myocardial infarction; and 18.6% were high risk or inoperable patients. Mean ejection fraction was 55.4%. A total of 1,000 lesions were treated in the 887 patients. Of the 1,000 lesions treated with ELCA in the 887 patients, 36% were in the right coronary artery; 33%, left anterior descending; 13%, circumflex; 3%, left main; and 16.6%, vein graft. By angiographic core laboratory analysis available for 752 (85%) patients with 839 lesions, lesions were 12.76 mm long. The minimum lumen diameter increased to 1.29 mm after the laser and finally to 1.95 mm after adjunctive percutaneous transluminal coronary angioplasty (PTCA) (which was performed in 93% of all lesions), with a final residual stenosis of 32.1% and Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow in 95%. Dissections of grades B, C, or D were seen after 22.0% of initial laser attempts, and postlaser perforations were noted in 2.6%. Additional such dissections accumulated after adjunctive PTCA but the perforation rate remained low. Procedural success was achieved in 84% of patients, but 1.2% died, 0.7% experienced Q-wave myocardial infarction (MI), and 2.7% required emergency bypass surgery. Multiple logistic regression analysis could not identify any independent predictors of these in-hospital complications. One-year mortality was 5.7% and the cumulative incidence of Q-wave MI was 1.5%. Coronary artery bypass graft (CABG) surgery was performed in 15.0% of patients whereas 25.5% required repeat percutaneous intervention with a target lesion revascularization rate of 31%. Independent predictors of death, Q-wave MI, or target lesion revascularization (which, combined, occurred in 35.6% of patients) were the absence of prior MI, ELCA in the circumflex, perforation after the procedure, and small (<2 mm) final minimal lumen diameter. Considering the large number of patients with high-risk lesions, laser angioplasty was performed with excellent procedural success rates and a reasonable incidence of major complications.

Circulation. 1997 Oct 7;96(7):2183-9Treatment of in-stent restenosis with excimer laser coronary angioplasty: mechanisms and results compared with PTCA alone.Mehran R, Mintz GS, Satler LF, Pichard AD, Kent KM, Bucher TA, Popma JJ, Leon MB

Intravascular Ultrasound Imaging and Cardiac Catheterization Laboratories, Washington Hospital Center, DC, USA

Background: This study determined the clinical safety, mechanisms, and 6-month results of excimer laser angioplasty (ELCA)+adjunct PTCA for the treatment of in-stent restenosis and (via lesion matching) compared the results of ELCA+PTCA to PTCA alone.

Methods And Results: Using quantitative angiography (QCA) and intravascular ultrasound (IVUS), we studied 107 restenotic previously stented lesions in 98 patients before and after intervention. QCA measurements included minimum lumen diameter (MLD) and diameter

stenosis (DS). IVUS measurements included stent, lumen, and intimal hyperplasia (IH=stent-lumen) cross-sectional areas (CSA) and volumes. In the 54 lesions treated with ELCA+PTCA, the MLD increased from 0.73+/-0.38 mm before ELCA to 2.10+/-0.47 mm after ELCA+PTCA (P<.0001); the DS decreased from 70+/-14% to 25+/-12% (P<.0001). By IVUS, the minimum lumen CSA increased from 1.58+/-0.78 mm2 before ELCA to 6.34+/-1.75 mm2 after ELCA+PTCA (P<.0001) as a result of an increase in minimum stent CSA from 7.70+/-2.41 to 9.10+/-2.60 mm2 (P<.0001) and a decrease in IH CSA from 5.25+/-2.84 to 2.63+/-1.41 mm2 (P<.0001). Volumetric analysis showed that tissue ablation (during ELCA) contributed 29+/-15%, tissue extrusion (during adjunct PTCA) contributed 31+/-14%, and additional stent expansion (during adjunct PTCA) contributed 40+/-16% to the overall lumen gain. There were no ELCA-related complications. Matched to lesions treated with PTCA alone, ELCA+PTCA resulted in greater lumen gain, more IH ablation/extrusion, larger final lumen CSA (IVUS), and a tendency for less frequent need for subsequent target vessel revascularization (TVR, 21% versus 38%, P=.0823).

Conclusions: ELCA safely and effectively ablates in-stent neointimal tissue. Adjunct PTCA extrudes neointimal tissue out of the stent and also further expands the stent. Compared with PTCA alone, ELCA+PTCA achieves better short-term and,potentially, better long-term results.

J Am Coll Cardiol. 1997 Sep;30(3):649-56Recanalization of chronic total coronary occlusions using a laser guide wire: a pilot studyHamburger JN, Gijsbers GH, Ozaki Y, Ruygrok PN, de Feyter PJ, Serruys PW

Thoraxcenter, University Hospital Rotterdam, The Netherlands. hamburge@card.azr.nl

Objectives: This study sought to prospectively evaluate the performance of a laser guide wire in crossing chronic total coronary occlusions in patients with a failed previous mechanical guide wire attempt.

Background: Despite continued refinement of mechanical hardware available forcoronary angioplasty, restoration and maintenance of blood flow through achronically occluded coronary artery remains a true challenge.

Methods: Fifty patients with a chronic total coronary occlusion and a previousfailed attempt at recanalization using mechanical guide wires were included. Amechanical attempt to cross the occlusion was repeated. In case of failure, anadditional attempt was made with the laser guide wire.

Results: The median age of occlusion was 22 weeks (range 5 to 200), and theocclusion length was 23 +/- 11 mm (mean +/- SD). A repeat mechanical attempt was successful in six cases (12%). Dissection occurred in five other cases, anddevice crossover was not attempted. Thus, in 39 patients an attempt was made withthe laser guide wire, with successful recanalization in 23 (59%). Thereby theoverall success rate increased from 12% to 58% (29 of 50 patients). The amount ofcontrast medium used was 515 +/- 154 ml, fluoroscopy time was 99 +/- 43 min, and total procedure time was 2 h 48 min (+/- 55 min). Procedural success was achievedin 26 cases and clinical success (procedural success without in hospital events) in 24. In-hospital events were two non-Q wave myocardial infarctions related tosubacute reocclusion. In one patient, a balloon dilation after laser guide wireperforation resulted in tamponade requiring pericardiocentesis. After asuccessful procedure, the angina class decreased from 2.9 +/- 0.2 to 1.4 +/- 0.7 at 3 months of clinical follow-up. Six month angiographic follow-up was completedin all 24 eligible patients and showed vessel patency in 20 (80%).

Conclusions: The use of the laser guide wire for recanalization of chronic total coronary occlusions refractory to treatment with mechanical guide wires isfeasible and relatively safe and was successful in 59% of cases. This device mustthus be considered a valuable addition to the interventional armamentarium andaccordingly will be evaluated in a randomized clinical trial.

Am Heart J. 1997 Aug;134(2 Pt 1):266-73

Laser balloon angioplasty combined with local intracoronary heparin therapy: immediate and short-term follow-up resultsGlazier JJ, Jiang AJ, Crilly RJ, Spears JR

Department of Medicine, Harper Hospital/Wayne State University School of Medicine, Detroit, MI 48201, USA

Laser balloon angioplasty (LBA) has been shown to acutely increase angiographic luminal dimensions after conventional balloon angioplasty (PTCA) without a favorable impact on chronic restenosis. Experimentally, laser and thermal energy enhance binding of heparin to the injured arterial wall and to the thrombus. In view of the anticoagulant, antiproliferative, and antifibrotic activities of the drug, a pilot study was performed to evaluate the potential safety and efficacy of LBA combined with local heparin therapy. Ten patients scheduled for elective PTCA were entered in the study. In each patient, a single lesion was treated with a laser balloon and coated with a heparin film (3000 I.U. at a concentration > 100,000 I.U./gm) immediately after optimal PTCA. The mean minimum luminal diameter and mean percent stenosis of the 10 treated lesions after PTCA were 1.62 +/- 0.39 mm and 37% +/- 9%, respectively. After LBA and local heparin therapy, the mean minimal lumen diameter increased to 2.01 +/- 0.34 mm (p < 0.01) and the mean percent stenosis decreased to 20% +/- 10% (p < 0.01). Systemic heparin was discontinued immediately after the procedure in all patients. Acute or inhospital complications, either major or minor, occurred in none (0%) of the 10 patients (95% confidence interval 0% to 31%); all were discharged home on the day after the procedure. All patients remained well and free of cardiac symptoms for at least 2 months after the procedure. However, restenosis developed in six (60%) of the 10 patients (95% confidence interval 26% to 88%) 2 to 6 months after the procedure. The results suggest that LBA and local heparin therapy, with discontinuation of systemic heparin immediately after angioplasty, is a safe treatment modality that yields favorable acute angiographic results.

Am J Cardiol. 1997 May 15;79(10):1343-9Angioscopy variables predictive of early angiographic outcome after excimerlaser-assisted coronary angioplastyLarrazet FS, Dupouy PJ, Dubois Rande JL, Ducot B, Kvasnicka J, Geschwind HJ

Department of Cardiology, University Hospital Bicêtre; Kremlin-Bicêtre, INSERM U 292, University of Paris, France

This study attempted to determine whether anatomic findings at angioscopy were associated with adverse early angiographic outcomes following excimer laser-assisted coronary angioplasty. Predictive factors of either coronary abrupt vessel closure or early (< or =24 hours) restenosis after percutaneous coronary angioplasty, including clinical and angiographic variables, have been widely evaluated. The role of angioscopic findings may contribute to identification of patients at risk for early poor outcome. Thirty-seven patients with severe lesions, including 23 total occlusions which underwent successful percutaneous transluminal coronary angioplasty (PTCA) with laser irradiation and adjunctive balloon dilatation (n = 35), or stand alone laser (n = 2), had concomitant angioscopic imaging of the target vessel. All patients had a 24-hour angiographic follow up. Early unfavorable outcome (n = 15) was defined as abrupt vessel closure or restenosis (> or = 50% stenosis) at 24 hours. By multivariate logistic regression analysis, immediate post-PTCA residual percent stenosis was associated with a poor outcome (restenosis: 33 +/- 22% vs no restenosis: 21 +/- 14%, p = 0.05). Angioscopic red thrombus aspect was the most significant correlate for early closure or restenosis (7 of 15 patients with unfavorable outcome vs 2 of 22 patients with favorable outcome, odds ratio, 22.9; p < 0.01) and was associated with a significantly higher early minimal lumen diameter loss (1 +/- 0.8 mm in the presence of a red thrombus vs 0.3 +/- 0.5 mm without thrombus, p < 0.005). Red thrombus appearance is associated with an unfavorable early angiographic outcome in patients who undergo laser-assisted coronary angioplasty.

Nihon Geka Gakkai Zasshi. 1996 Jul;97(7):526-31Clinical experience of laser angioplasty for the peripheral and coronary arterial diseasesOkada M, Yoshida M

Department of Surgery, Kobe University School of Medicine, Japan.

In recent years, laser angioplasty has been widely performed in the world. Since the 1980's we have investigated anigoplasy using Argon laser for patients with peripheral and coronary

arterial diseases. This technique aims to open the obstructive arterial lumen. Based on the excellent results of experimental studies, this technique has been clinically applied. Laser angioplasty was carried out in 98 patients with stenotic or occlusive lesions of the peripheralarteries and 10 patients with anginal attack. Argon laser and an optical fiber delivery system with metal tip probe with thermal feedback control system were used for laser angioplasty. This procedure was performed under angioscopic and intravascular ultrasound imaging. Primary clinical success was achieved in 97 (82%) of all 119 lesions, that is, 53 (91%) of 58 in the stenotic lesions and 44 (72%) of 61 in the occlusive lesions. There were no complications required emergency operation. At 95 months of follow-up, the cumulative patency rate was 80% in 83 limbs with primary success. In the 43 stenoses and 40 occlusions, the cumulative patency rare were 87% and 71%, respectively. On the other hand, laser was simultaneously applied at the time of operation for 10 patients with anginal attack in addition to coronary artery bypass grafting. Thus, laser angioplasty was safe and effective to increase the initial success rate for the lesions that were difficult to treat by balloon anigoplasty. Angioscopy and intravascular ultrasound imaging were useful for the observation of the newly recanalizedchannel by lasing and selection of the recanalization technique, such as laser angioplasty, atherectomy and stent, according to the characterization of the lesions. These results suggested that laser angioplasty might be a useful treatment for patients with chronic peripheral arterial occlusion and improve the long-term patency rate by eliminating restenosis more than conventional balloon angioplasty.

Semin Interv Cardiol. 1996 Jun;1(2):117-9Laser angioplasty: historical perspectiveSanborn TA

Cardiology Division, New York Hospital-Cornell Medical Center, New York 10021,USA

Serious interest in laser angioplasty began in the early 1980s in an attempt to solve two of the primary limitations of balloon angioplasty, recanalization and restenosis. By demonstrating the ability of laser irradiation to vaporize atherosclerotic tissue, it was logical to hypothesize that this powerful tool may allow recanalization of lesions that could not be crossed by conventional guidewire and balloon technology. With refinements in laser fibreoptics and catheter delivery systems, several laser systems were approved for clinical use as recanalization devices in both peripheral and coronary arteries. However, the requirement to follow laser angioplasty with conventional balloon angioplasty in the majority of cases and the lack of an effect of laser tissue removal (debulking) on restenosis has limited a broader acceptance of this technology. Perhaps improved techniques discussed later in this series such as saline infusion and better fibreoptic-lens systems will allow laser angioplasty to offer a true niche in interventional cardiology.

Clin Cardiol. 1996 Mar;19(3):232-8Peripheral artery recanalization in humans using balloon and laser angioplastyBarbeau GR, Seeger JM, Jablonski S, Kaelin LD, Friedl SE, Abela GS

Department of Medicine, Laval University, Quebec, Canada.

The treatment of patients with complex peripheral arterial disease and those who have had previous unsuccessful attempted revascularization procedures can be clinically challenging. Initial treatment was begun using therapy by percutaneous balloon and laser angioplasty, then proceeding to bypass surgery if severe ischemia persisted. Both percutaneous and cut-down approaches were used to access totally occluded arteries. An attempt was made to cross the occlusion mechanically with either a guide wire or an activated laser probe. If laser recanalization was not successful, the patient underwent bypass surgery or was managed with medication unless an amputation was necessary. Following initial screening of 381 patients, 115 procedures were performed on 103 patients. In 31 procedures (28 patients), only balloon angioplasty was performed. In 84 procedures (75 patients), laser recanalization was attempted: 55 percutaneously and 29 by cut-down. Overall technical success (crossing the obstruction without perforation) was 86/115 (75%). Technically successful procedures werecharacterized by shorter arterial occlusions than were technical failures (8.4 +/- 1 cm vs. 14.3 +/- 1.9 cm; p < 0.004). Clinical success (residual stenosis < 50%, symptom relief, improved ankle brachial index > or = 0.15, and no complications) was achieved in 22/31 (71%) of balloon angioplasty procedures alone. The stenoses decreased from 98 +/- 4% to 31 +/- 24%, p < 0.00001. Combined percutaneous laser and balloon angioplasty had a technical success of 36/55 (65%). Stenoses were reduced from 99 +/- 2% to 56 +/- 14% after laser angioplasty, to

30 +/- 15% after balloon angioplasty, p < 0.0001. Laser angioplasty performed via a cut-down had a clinical success of 9/29 (31%). However, major complications were rare. Device staging for treatment of peripheral vascular disease provides additional options for patients who are at high surgical risk and/or in whom standard therapy has failed.

Int J Technol Assess Health Care. 1996 Winter;12(1):104-25A cost-utility analysis of laser-assisted angioplasty for peripheral arterialocclusionsSculpher M, Michaels J, McKenna M, Minor J

Brunel University

Despite the perception of many people that lasers represent the cutting edge ofhigh-technology medicine, this form of medical technology has been subject torelatively little rigorous evaluation. This dearth of research relatesparticularly to economic evaluation, where there have been few attempts tojustify the high cost of laser equipment. This paper details an economicevaluation of the use of laser technology as a secondary adjunct to angioplastyto treat peripheral arterial occlusions. Using data from a range of sources,including a published randomized trial, a cost-utility model is developed toestimate the costs and benefits of the laser, relative to standard angioplasty.The best available data indicate a cost-effective role for the laser, butimportant areas of uncertainty exist, including the laser's secondaryrecanalization rate, which has been estimated on the basis of limited numbers of patients. This uncertainty suggests that further research is required beforewidespread diffusion of the laser for use in this clinical context.

Cardiovasc Intervent Radiol. 1995 May-Jun;18(3):162-7Femoropopliteal artery recanalization: factors affecting clinical outcome ofconventional and laser-assisted balloon angioplastyOdink HF, de Valois HC, Eikelboom BC

Department of Radiology, St. Antonius Hospital, Nieuwegein, The Netherlands.

Purpose: The clinical efficacy of 44 successful conventional and laser-assisted recanalizations of the femoropopliteal artery was assessed in a noncomparative study by the life-table method.

Methods: Laser-assisted angioplasty using continuous laser and a sapphire probe was performed to achieve primary recanalization in femoral artery occlusions when conventional guidewire recanalization had already failed. Nineteen of the patients underwent a conventional recanalization (PTA; mean length of occlusion 4.4 +/- 4.1 cm), and 25 underwent percutaneous laser-assisted angioplasty (PLA; mean length of occlusion 10.1 +/- 6.7 cm).

Results: There was no statistical relation between the preprocedure Fontaine classification and the success rate in the PTA cases (p = 0.25), whereas there was a statistical relation in the PLA cases: The success rate in patients preprocedurally classified as Fontaine II was better than in those classified as Fontaine III/IV (p = 0.05). After a 3-year follow-up the patency rate in the patients with the PTA recanalizations was 37% and that in those with the PLAprocedure was 53%. This difference was not statistically significant (p = 0.47).

Conclusion: It is concluded that the laser should remain an investigational device.

Zhonghua Yi Xue Za Zhi (Taipei). 1994 Jan;53(1):1-6Percutaneous excimer laser coronary angioplasty: animal models and the first human experience in TaiwanChen JS, Hwang CL, Kwan PS, Kao MC, Chen YT

Department of Medicine, Taichung Veterans General Hospital, Taiwan, R.O.C.

Clinical studies with excimer laser coronary angioplasty (ELCA) have been published in USA and Germany for lesions too difficult for use of routine balloon angioplasty. The purpose of the study was to evaluate the safety and short-term effects of excimer laser radiation applied to canine coronary angioplasty, and to report the first experience with percutaneous coronary excimer laser angioplasty and adjunctive percutaneous transluminal coronary angioplasty (PTCA) in a human subject on Taiwan.

Methods: Twelve canine subjects were studied. An excimer laser (Technolas Inc. Max-10), 20 Hz, 35 mJ/mm2, and 60 ns pulse was used.

Results: There were no perforations, with minimal dissection on the arterial intimal layer after using the bare-tip (crude single fiber-optic) fiber laser. The human subject showed partially successful recanalization after ELCA, with no residual stenosis after adjunctive PTCA for an occluded left anterior descending (LAD) artery (proximal lesion). A 0.014-in guide wire was used. There were no complications except for premature ventricular contractions during the procedure.

Conclusions: The percutaneous excimer laser angioplasty is an effective and safe tool for treating coronary artery disease.

Z Kardiol. 1995 May;84(5):373-6Crossing chronic coronary artery occlusions with a "laser wire" after failedattempted recanalization with other techniquesSievert H, Scherer D, Merle H

Abteilung Kardiologie und Angiologie Krankenhaus Bethanien, Frankfurt.

The success rate of catheter recanalization of occluded coronary arteries is 50% to 80%. The reason for failure is frequently an occlusion which is to hard. As examples, two patients are reported with very hard coronary artery occlusions which were 5 months and 2 years old, respectively. There had been prior unsuccessful attempted treatment with other techniques. These occlusions could be recanalized with an 0.018 inch laser wire. Afterwards, a balloon dilatation could be carried out via the laser wire. The procedure was successful in both cases.

Cardiovasc Intervent Radiol. 1995 Jan-Feb;18(1):1-8Laser angioplasty of peripheral arteries: an epilogue?Lammer J

Department of Angiography and Interventional Radiology, University Vienna,Austria

This review gives a short overview of the results of 15 years of experimental and clinical work on laser angioplasty. Experimentally, photothermal and photomechanical ablation of plaque could be demonstrated. However, laser angioplasty did not cause reduction of platelet adhesion and intimal hyperplasia. Clinically, the technique of laser angioplasty was continuously improved until the initial recanalization rates and long-term patency rates in femoropopliteal artery occlusions were the same as the success rates of percutaneous transluminal angioplasty (PTA). This was proven by various randomized studies. Currently,laser angioplasty cannot be proposed as a routine procedure because it is an expensive technology. However, laser recanalization and debulking of total occlusions should be further developed, especially in combination with endoluminal graft placement.

Zhonghua Xin Xue Guan Bing Za Zhi. 1993 Jun;21(3):161-2, 187-8

Percutaneous transluminal peripheral excimer-laser angioplasty: two successful cases reportXu CB

People's Hospital, Beijing Medical University

The excimer-laser (XeC1) operating at 308 nm, ablates by means of photochemical mechanisms with minimal thermal injury. Two male patients, 53 years and 67 years, with symptomatic peripheral vascular disease underwent percutaneous transluminal excimer-laser angioplasty (PTPELA). Both of them experienced claudication at a short walking distance and had superficial femoral or initial segmental femoral occlusions from 4 cm to 7 cm in length. The laser emitted 120ns pulses at 20 Hz with delivering 16-18 mJ by 7F and 9F catheter, energy density was about 4mJ/mm. The irradiation time was 157 seconds and 185 seconds respectively. Successful recanalization occurred in our two cases, the residual stenosis were less than 20%. The acute outcome was good without any complications.

Cathet Cardiovasc Diagn. 1993 Jan;28(1):44-6Use of excimer laser in the treatment of chronic total occlusion of a coronary artery that cannot be crossed with a balloon catheterBerger PB, Bresnahan J

Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.

The inability to advance a balloon across a chronically occluded coronary artery that has been crossed with a guidewire occurs in 5% of patients with chronic occlusions. In this report, a new indication for the excimer laser is described: the recanalization of a chronic occlusion that has been crossed with a guidewire that cannot be crossed with a balloon catheter.

Am Heart J. 1992 Dec;124(6):1467-72Percutaneous angioscopic evaluation of luminal changes induced by excimer laser angioplastyNakamura F, Kvasnicka J, Uchida Y, Geschwind HJUnité d'Hèmodynamique, University Hospital Henri Mondor, University of Paris XII, Creteil, France

Angioscopy has been shown to provide more detailed information on lesion morphology before and after interventional procedures than angiography. Therefore to evaluate the effects of laser angioplasty, angioscopy was performed in five patients with peripheral or coronary vascular disease who underwent excimer laser angioplasty. The excimer laser was operated at 308 nm, 135 nsec, 25 Hz, and 40 to 60 mjoules/mm2 and was coupled into multifiber wire-guided catheters of 1.4 to 2.0 mm diameter for coronary lesions and into catheters of 2.2 mm diameter for peripheral lesions. There were three coronary (one left anterior descending, one circumflex, one right coronary artery) and two peripheral (one common iliac artery, one superficial femoral artery) lesions. Angioscopy was successfully performed before and after laser ablation without any complications in all five lesions. The characteristics of angioscopic findings after excimer laser angioplasty consisted of flaps, fractures of plaques, and abundant tissue remnants. There was no apparent thermal injury. Recanalized channels were small and irregular. These results indicate that (1) angioscopy is effective and safe for evaluation of lesion morphology after laser angioplasty; (2) laser ablation does not result in thermal injury; and (3) irregular channels after recanalization and abundant tissue remnants may explain the suboptimal results after laser angioplasty.

Circulation. 1992 Sep;86(3):820-7Morphological predictors of acute complications after percutaneous excimer laser coronary angioplasty. Results of a comprehensive angiographic analysis: importance of the eccentricity indexGhazzal ZM, Hearn JA, Litvack F, Goldenberg T, Kent KM, Eigler N, Douglas JS Jr, King SB 3rd

Division of Cardiology, Andreas Gruentzig Cardiovascular Center, Emory University School of Medicine, Atlanta, Ga

Backgrounds : Percutaneous excimer laser coronary angioplasty (ELCA) is a new technique for recanalization of arteries obstructed by coronary atherosclerosis. This study was conducted

to assess the complication rate and determine the influence of clinical and angiographic characteristics on complications after ELCA.

Methods and results : A detailed, quantitative, angiographic core laboratory analysis of patients undergoing ELCA was performed by two experienced angiographers who were not the primary laser angioplasty operators. Two hundred patients underwent 203 separate procedures on 220 lesions at three medical centers. Laser success was achieved in 180 lesions (81.8%) and procedural success in 199 (90.5%). Emergency coronary artery bypass graft (CABG) was required in five patients (2.5%). One patient suffered a Q wave myocardial infarction; there were no deaths. Also, acute closure and perforation occurred in 10 (4.5%) and three (1.4%) vessels, respectively. Coronary dissections after laser treatment were seen in 36 vessels (16.4%). Multivariate analysis found two independent preprocedural factors related to complications: eccentricity index, which is the percent deviation of the lesion lumen from the center of the artery (p = 0.0007), and proximal vessel diameter (p = 0.033). In addition, an abrupt proximal face of the lesion was associated with angiographic complications by univariate analysis (p = 0.051). Multivariate analysis showed the eccentricity index (p = 0.032) to be the only independent predictor for the occurrence of any one or more of the important complications (emergency CABG, perforation, acute closure, or Q wave myocardial infarction), whereas lesion angle greater than 45 degrees was a significant univariate predictor (p = 0.029). Other predictors of complications with balloon percutaneous transluminal coronary angioplasty, such as increased lesion length, rough edges, calcification, ulceration, and branch point, were not predictive of complications with the excimer laser.

Conclusions : The degree of lesion eccentricity is the most powerful predictor of complications after ELCA. This and other morphological predictors may be of benefit in the selection of patients for ELCA as well as directing future development of this new technology.

Nihon Geka Hokan. 1992 Mar 1;61(2):168-89An experimental study of excimer laser angioplastyOgino H

Department of Cardiovascular Surgery, Faculty of Medicine, Kyoto University, Japan

An excimer laser, which is a pulsed ultraviolet laser and ablates tissue precisely with no thermal injury, is expected to coronary laser angioplasty. We transmitted XeCl excimer laser (308 nm) via a 400 microns fused silica fiber. In the first experiment, we studied about excimer laser ablative effects to normal canine arteries and atherosclerotic rabbit aortas, and about healing responses following excimer laser irradiation in both models. Surfaces after excimer laser ablation were slightly rough but no thermal injury was found in the media. And for healing process of normal canine arteries, endothelial cells appeared at 3 weeks and completely covered surfaces with fibrointimal ingrowth at 3 months. In the rabbit aortas, at 3 weeks there was reconstruction of the surface. At 2 months no accelerated atherosclerotic or aneurysmal changes were observed. In the second, with this excimer laser (short pulse) and 400 microns fused silica fibers (distal fiber-end power: 3-6 mJ/pulse), we performed transluminal laser angioplasty to recanalize totally occluded canine femoral arteries under an angioscopic guidance. We cold recanalize 8 of 9 totally occluded arteries with no thermal injury of adjacent tissue, though perforations were observed in 7 of 9 arteries. In the third, we used a newly-developed long pulse excimer laser, with which distal fiber-end energy was about 3 to 4 times as much as the short pulse one, to recanalize totally occluded canine arteries. In result, recanalization was performed in 6 of 8 arteries rapidly with little thermal injury. However, we observed perforations in 6 of 8 arteries like the short pulse one. Multifiber catheter ("over the wire system") coupled with this long-pulse excimer laser was used to reconstruct stenotic iliac arteries of atherosclerotic rabbit models. The procedure was successful in all the 5 rabbits. In conclusion, our preliminary results suggested that further developments of a more powerful and longer pulse-duration excimer laser, optic delivery system and guidance system would make excimer laser angioplasty safer and more effective method in the near future.

Ann Chir Gynaecol. 1992;81(1):19-22Peripheral excimer laser-assisted angioplasty. Preliminary clinical experienceSavolainen H, Keto P, Verkkala K, Schröder T, Mattila S

Department of Thoracic and Cardiovascular Surgery, University Central Hospital, Helsinki, Finland

A non-thermal Xenon-Chloride excimer laser was used for peripheral arterial recanalization in eight patients with obliterating atherosclerosis of the superficial femoral artery. All patients had a total occlusion with severe claudication or pain at rest. There were three complications, which all led to thrombosis of the irradiated artery. In one, the puncture site in the artery had to be closed operatively. All vessels were followed up radiographically three months after the procedure. In seven patients the vessel was patent. Several investigators have warranted caution in using thermal lasers (continuous wave Nd:YAG or argon) for angioplasty. The non-thermal excimer laser is a viable alternative--although not without problems. Initial experiences with the new device are described.

Lasers Surg Med. 1992;12(6):576-84Effect of force on ablation depth for a XeCl excimer laser beam delivered by an optical fiber in contact with arterial tissue under salineGijsbers GH, van den Broecke DG, Sprangers RL, van Gemert MJ

Laser Center, Academic Medical Center, Amsterdam, The Netherlands

The effect of force applied to a 430 micron single fiber, delivering 60 pulses of 308 nm XeCl laser radiation at 20 Hz, on the ablation depth in porcine aortic tissue under saline has been investigated. Energy densities of 8, 15, 25, 28, 31, 37, and 45 mJ/mm2 were used. Force was applied by adding weights from 0 to 10 grams to the fiber. The fiber penetration was monitored by means of a position transducer. At 0 grams, the ablation depth increased linearly with incident energy density, but the fiber did not penetrate the tissue; with any weight added, the fiber penetrated the tissue at energy densities above 15 mJ/mm2. The fiber did not penetrate during the first several pulses, possibly due to gas trapped under the fiber. After these first pulses, a smooth linear advancement of the fiber began, which lasted until the pulse train stopped. The ablation depth increased with increasing energy densities and weights. This effect was largest above 25 mJ/mm2 where the ablation efficiencies (unit mm3/J), with weights added to the fiber, were substantially larger than values found in 308 nm ablation experiments described in the literature, which were conducted with either a focused laser beam or a fiber without additional force. The results imply that in 308 nm excimer laser angioplasty, force must be applied to the beam delivery catheter for efficient recanalization, and that experiments performed with a focused beam or without actual penetration of the fiber do not represent the situation encountered in excimer laser angioplasty.

Thorac Cardiovasc Surg. 1991 Dec;39 Suppl 3:248-51Laser angioplasty of peripheral arterial occlusive diseaseHuppert PE, Seboldt H, Duda SH, Seiter H, Claussen CD, Hoffmeister HE

Department of Diagnostic Radiology, Eberhard-Karls-Universität Tübingen, Germany.

To evaluate the impact of laser ablation of arteriosclerotic material on the long-term results of transluminal angioplasty, 103 patients were treated by laser-assisted recanalization of peripheral arterial occlusion and followed-up for 6 and 12 months. Two pulsed laser systems (308 nm-excimer laser and 504 nm-dye laser) were tested. Laser energy was transmitted via wire-guided 4.5-, 7- and 9-French multifiber catheters. Stand-alone laser angioplasty was possible in 22% of the patients, especially in the popliteal and the lower-limb arteries. Compared to the results of balloon dilatation in the literature, the clinical success rate at 6 and 12 months after the treatment was better in occlusions with a length between 6 and 10 cm, however no improvement was seen in either shorter or longer occlusion. Due to the limited size of percutaneously applicable catheters, laser treatment and pretreatment seemed to be of most benefit in distal femoropopliteal arteries and in lower-limb arteries. Clinical improvement after revascularization depends on a sufficient run-off in branching vessels distal to the recanalized artery segment.

Arch Mal Coeur Vaiss. 1991 Nov;84(11):1537-41Primary results of laser recanalization in the endovascular treatment ofarterial stenosis and occlusion of the lower limbs. Apropos of 45 treated cases].Poyen V, Alessandri C, Duport G, Bergeron P

Service de cardiologie, hôpital Saint-Joseph, Marseille

Forty-five lower limb arterial lesions were treated by Nd Yag laser angioplasty using 1.4 and 2 mm hybrid catheters in 31 patients. This population comprised 28 men and 3 women (average

age 63.8 +/- 3 years) 20 were in Stage II, 5 in Stage III and 6 in Stage IV of Fontaine's classification. The arteriographic lesions were 22 occlusions with an average length of 12.3 cm and 23 stenoses averaging 87% luminal reduction a few millimeters long to a maximum of a string of stenoses. Seventeen of these lesions were very calcified. The stenoses were situated on the iliac artery (7 cases), superficial femoral artery (28 cases), popliteal artery (9 cases) and the tibio-peroneal artery (1 case). There were no fatalities or recourse to emergency surgery. All patients underwent complementary balloon dilatation. The immediate patency rate was 91% in stenotic and 72% in occlusive lesions. At one week, the patency rate for stenotic lesions was unchanged but it had fallen to 59% for occlusive lesions (arteriographic evaluation). Angioscopy was used 22 times: it was indissociable to laser angioplasty as it enabled diagnosis and controlled the result. The use of thermal laser with hybrid catheters (metallic window tip) in endovascular procedures is a safe and effective method of treating stenosis and occlusion of lower limb arteries.

Rev Prat. 1990 Nov 11;40(26):2448-54Laser and arterial recanalizationGeschwind H, Dubois-Randé JL

Service d'explorations fonctionnelles, CHU Henri-Mondor, Créteil.

Interventional cardiorhythmology was born with the invention of electrical catheter ablation of the common atrioventricular bundle of His as a palliative treatment of supraventricular arrhythmias refractory to medicinal treatment. This method is now used as a curative treatment. In Wolff-Parkinson-White syndrome, all accessory pathways, whatever their location, can be destroyed with a very high success rate (96 p. 100) and very low morbidity and mortality rates. Reentrant nodal tachycardias can also be treated by catheter ablation with, however, a low risk of atrioventricular block which, for the moment, limits its indications. In intractable ventricular tachycardias, its indications will certainly be extended and its efficacy will increase since numerous recent studies have identified a limited, slow-conduction area (arrhythmogenic substrate) as being the real target for ablation. Other sources of energy are also used for the same purposes, including radiofrequency currents with results that are promising but vary according to the type of arrhythmia treated. Thus, interventional cardiorhythmology is progressively replacing surgery.

Am J Cardiol. 1991 Oct 15;68(10):1079-86Laser-assisted versus mechanical recanalization of femoral arterial occlusionsTobis JM, Conroy R, Deutsch LS, Gordon I, Honye J, Andrews J, Profeta G, ChatzkelS, Berns M

Division of Cardiology, University of California, Irvine

A randomized clinical trial was performed to test the hypothesis that a laser-heated probe is superior to standard techniques to reopen occluded femoral arteries. Twenty patients were treated with a standard guidewire and balloon dilation method. In a second group of 20 patients, the laser probe was initially used as a nonheated mechanical device. If the probe was unsuccessful in mechanically reopening the artery, an Argon laser was activated to heat the probe. The mean length of occlusion was 15.9 +/- 10.3 cm. The success rate for the laser probe was 15 of 20 (75%), which was not significantly different from the standard method, 19 of 20 (95%). Most of the success in the laser-probe group was due to the probe's mechanical properties. The laser probe was successful as a cold, mechanical device in 13 of 15 (87%) arteries. It was necessary to heat the probe in 5 patients. When heated, the laser probe assisted recanalization in 2 but perforated the artery in 3 cases. The results of this randomized trial do not support the hypotheses behind the use of the thermal laser probe. The laser probe functions primarily as a mechanical device. The thermal activation does not significantly improve the success rate without increasing the risk of perforation. This small additional benefit does not justify the large cost of current thermal laser devices. This controlled study

also demonstrates a higher success rate in long occlusions than previous reports of mechanical balloon recanalization. This is due to a combination approach of retrograde andanterograde probing of the occluded segment.

Jpn Circ J. 1991 Jun;55(6):591-600A comparison of excimer laser, thermal probe, and mechanical devices for recanalizing occluded human arteriesMoriuchi M, Tobis JM, Mcrae M, Mallery JA, Macleay L, Moussabeck O, Berns M, Henry WL

2nd Department of Internal Medicine, Nihon University, School of Medicine, Tokyo, Japan

To evaluate the mechanism of excimer laser recanalization and compare the results with those of laser-assisted thermal probe recanalization and mechanical recanalization, a total of 42 human atherosclerotic totally occluded arterial segments (2-15 cm long) were recanalized by excimer laser with a 400-800 micron quartz fiber pulsed at 20 Hz with 50 mJ/mm2 of energy (n = 21), an Argon heated thermal probe at 10-12 watts (n = 11), a guidewire directed through a 6 Fr multipurpose catheter, or an angioplasty balloon catheter (n = 10). On histologic examination, the excimer laster created a single round lumen or multiple lumens ("Swiss-cheese" like appearance) with no evidence of thermal injury at the perimeter of the lumen. The incidence of perforation in vitro was less with an excimer laser catherter (8/21 or 38%) than with the thermal prove (10/11 or 91%) (p less than 0.01). However, serial histologic cross-sectional examination showed that the pathway of the devices were essentially the same in all recanalization procedures. The pathway of the device was located outside the atheroma but proximal to the internal elastic membrane in 13 arteries with the excimer laser (62%), in 10 arteries with the thermal probe (91%), and 8 arteries with mechanical devices (80%). These results indicate that although the eximer laser could recanalize human atherosclerotic arteries without thermal injury, the fiber frequently deflected around firm atherosclerotic plaque and advanced in a dissection plane between the plaque and media. A similar course was noted for the thermal probe or during mechanical recanalization with a guidewire and catheter. To insure the safety of an excimer fiber or a thermal probe to reopen complete occlusions, better guidance systems must be developed.

Dtsch Med Wochenschr. 1991 Feb 1;116(5):161-7Peripheral excimer laser angioplasty. The indications, methods and clinical resultsHuppert PE, Duda SH, Seboldt H, Karsch KR, Claussen CD

Abteilung für Radiologische Diagnostik, Universität Tübingen.

Between March 1989 and January 1990, percutaneous transluminal excimer laser angioplasty was performed in 61 patients (40 men and 21 females; mean age 66 [41-86] years) with 65 peripheral arterial occlusions (iliac: 11, femoropopliteal: 48, tibial: 5, left subclavian artery: 1). The average ankle-arm index before treatment was 0.45 (0.2-0.8) for iliac, 0.52 (0-0.7) for femoropopliteal and 0.3 (0.1-0.4) for tibial occlusion. Recanalization was successful in 58 occlusions, but additional balloon dilatation was necessary in 54. The mean residual stenosis degree after laser application was 54%, after balloon dilatation 22%. Postangioplasty thromboembolism occurred in five patients. Intravascular stents were implanted in 11 patients because of extensive dissection or high-grade restenosis. After four weeks the clinical findings were improved in 54 of the 58 patients, in 47 even after six months. At that point the average ankle-arm index was 0.88 (0.5-1.1) after iliac, 0.79 (0.6-1.15) after femoropopliteal and 0.6 (0.4-0.7) after tibial recanalization.

Am J Cardiol. 1990 Dec 15;66(20):1445-50Recanalization of chronic total coronary arterial occlusions by percutaneous excimer-laser and laser-assisted angioplastyWerner GS, Buchwald A, Unterberg C, Voth E, Kreuzer H, Wiegand V

Department of Cardiology, Georg-August University, Goettingen, Federal Republic of Germany.

A low primary success and high restenosis rate after recanalization of chronic total occlusions by conventional coronary angioplasty have encouraged the application of new interventional techniques like excimer-laser angioplasty. In 39 patients with a coronary occlusion for 1 to 12 months, recanalization was attempted by laser angioplasty through a multifiber-catheter coupled to a pulsed XeCl excimer laser. After successful passage of the occlusion by a standard

guidewire in 27 patients (69%), the laser catheter was advanced over the central guidewire and crossed the occlusion in 25 patients (64%). In 2 patients with unsuccessful passage of the laser catheter, the subsequent attempt with a low profile balloon catheter also failed. In 19 of the 25 patients with successful laser recanalization, the residual stenosis exceeded 50% and was therefore followed by additional balloon angioplasty. The average residual stenosis after laser was 61 +/- 17% of the vessel diameter, and after balloon angioplasty 28 +/- 9% (n = 19), whereas after laser angioplasty alone it was 38 +/- 5% (n = 6). No complications associated with the laser application were observed. Angiographic control after 24 hours showed a reocclusion of 2 (8%) recanalized vessels. In this pilot study, laser angioplasty proved to be a safe and feasible method for the treatment of chronic total coronary occlusions. Because it was necessary to guide the catheter by a central wire, the primary success was limited by a successful passage of the wire of the occlusion. The rate of stand-alone laser angioplasty has to be increased by future improvements of the technique to enable a comparative evaluation of this method with conventional angioplasty.

Artif Organs. 1990 Feb;14(1):28-40Cardiovascular laser applicationSchaldach M

Zentralinstitut fur Biomedizinische Technik, Friedrich-Alexander Universitat Erlangen Nurnberg, Federal Republic of Germany

With the invention of the laser, many clinical disciplines have taken advantage of this new energy source. Its precision, intensity and energy density is superior to all other known surgical devices. Based on the principle of light amplification from a photon-emitting resonator, the monochromaticity, collimation and coherence provide the high-energy density of the laser beam for medical applications. The state-of-the-art and future potential of laser use in cardiovascular diseases will be reviewed. Most of the work in this field has been accomplished during the past decade with numerous research projects. Although many technical advances have been made, so far the results in cardiovascular medicine are in the areas of vessel anastomosis, ablation of conduction passes for arrhythmia therapy, and angioplasty. In this paper, special attention will be given to the recent success in XeCl excimer laser application for photodecomposition of tissue with a goal of improved recanalization. The high-power density of the XeCl excimer laser provides significant advantages for the disruption of both embolic and calcified plaque. Regardless of the type of tissue ablated, gross, histologic, and ultra-structural analysis confirmed the absence of thermal injury in luminar recanalization as well as in animal studies. Progress in the manufacture of catheters, with multiple very small diameter fibers, led to the decisive breakthrough in clinical laser angioplasty. Peripheral as well as coronary arteries have been successfully recanalized followed by balloon dilatation. The ease of application and the success achieved thus far have resulted in an optimistic assessment for laser medicine.

Arch Mal Coeur Vaiss. 1989 Dec;82(12):2009-13Coronary endarterectomy using an excimer laser. Preliminary peroperative results]Ollivier JP, Gandjbakhch I, Avrillier S, de Bourayne J, Delettre E, Bussiere JL, Cabrol CService de cardiologie, hôpital militaire du Valde-Grâce, Paris

From experimental and clinical experience, safe coronary angioplasty cannot be performed with CW lasers. The excimer laser does present a number of advantages in vitro: non-thermal ablation of plaques and a linear relationship between the number of pulses and the depth of the crater, so that tissue ablation is quantitatively predictable. A 308 nm, 20 ns pulse duration, 1 to 5 repetition rate laser was specifically designed for clinical application. During cardiopulmonary bypass prior to bypass grafting in 10 symptomatic patients, a 1 mm diameter core UV-tipped fiberoptic was introduced via the coronary arteriotomy and directed in contact with the coronary stenosis. Laser power was progressively increased until the stenosis or occlusion was recanalized. The quality of this angioplasty was controlled by calibration of he neo-lumen, cardioplegia solution flow through the lased segment, and 8th day coronary angiography. The laser treated coronary segments of the first 4 patients showed clearly parallel-lined patent neo-lumen despite competitive bypass graft flow. The main limitation of the method is that laser coronary recanalization is confined to the fiber core diameter. The authors conclude that: 1) excimer laser angioplasty is a safe and efficient intra-operative

procedure; 2) the most critical problem for percutaneous laser angioplasty remains flexibility of the apparatus as the fiber diameter must be large enough to provide an adequate arterial neo-lumen.

Z Kardiol. 1989 Nov;78(11):689-700Use of the thermal laser effect of laser irradiation for cardiovascular applications exemplified by the Nd:YAG laserIschinger T, Coppenrath K, Weber H, Enders S, Unsöld E, Hessel S

Abteilung für Kardiologie und Pneumologie, Klinikum München-Bogenhausen

Techniques of percutaneous transluminal application of laser energy for vessel recanalization have been used clinically since 1983. The commonly used Nd:YAG and argon lasers achieve ablation of atherosclerotic plaques by thermal action (vaporization). In order to reduce undesirable thermal damage in the neighborhood of the target tissue and to avoid vessel perforation, optimal irradiation parameters, modified (atraumatic) fiber tips (hot tips, sapphires), and steerable catheter systems needed to be implemented. Favorable results from peripheral application have encouraged use in the coronary circulation. More recently, coagulative tissue effects of circumferential irradiation of the vessel wall during balloon dilatation have been used for stabilization of acute and late results after mechanical balloon angioplasty. Enhancement of the differential light absorption of atherosclerotic plaque by use of biological dyes may further improve selective intravascular laser application. Intraoperative ECG-guided laser coagulation of arrhythmogenic areas of myocardium is a method for treatment of malignant arrhythmias. Transluminal non-operative application of myocardial laser photocoagulation has now been tested experimentally and shown to be safe and effective. There was no arrhythmogenicity or thermal damage of coronary arteries associated with this method. Innovative techniques such as nanosecond pulsed excimer lasers (athermal action) and development of "intelligent" lasers--which are equipped with spectroscopy-guided feedback systems for plaque recognition--have opened new perspectives and will further improve safety and efficacy of clinical laser application. However, according to current experience, the thermally acting Nd:YAG laser is an effective and versatile mode of laser therapy for selected cardiovascular indications.

Am Heart J. 1989 Nov;118(5 Pt 1):934-41Vascular spasm complicates continuous wave but not pulsed laser irradiationGal D, Steg PG, Rongione AJ, DeJesus ST, Clarke RH, Isner JM

Department of Biomedical Research, St. Elizabeth's Hospital, Tufts University School of Medicine, Boston, MA

Preliminary clinical experience with laser angioplasty has suggested that arterial spasm may complicate attempts to employ laser light to accomplish vascular recanalization. The present study was designed to investigate the role of energy profile on the development of arterial spasm during laser angioplasty. Laser irradiation was delivered percutaneously in vivo to New Zealand white rabbits and to Yucatan microswine with or without atherosclerotic lesions induced by a combination of balloon endothelial denudation and atherogenic diet. Continuous wave (CW) laser irradiation from an argon ion gas laser (wavelength 488 to 514 nm) was applied to 23 arteries, while 16 arteries were irradiated using a pulsed xenon chloride (308 nm) or xenon fluoride (351 nm) excimer laser. Arterial spasm, defined as greater than 50% reduction in luminal diameter narrowing, complicated delivery of laser light to 17 (74%) of the 23 arteries irradiated with the CW argon laser. Spasm was consistently observed at powers greater than 2 W, at cumulative exposures greater than 200 seconds, and at total energy greater than 200 joules. Spasm was typically diffuse (including the length of the vessel) and protracted (lasting up to 120 minutes). Intra-arterial nitroglycerin (up to 300 micrograms) produced only temporary and incomplete resolution of laser-induced spasm. In contrast, spasm was never observed in any of the 16 arteries in which laser angioplasty was performed using a pulsed laser (0.95 to 6.37 joules/cm2, 10 to 50 Hz, 48 to 370 seconds). Thus CW but not pulsed laser angioplasty may be complicated by arterial spasm.

Lasers Surg Med. 1988;8(5):464-8Percutaneous transluminal excimer laser angioplasty in total peripheral artery occlusion in manWollenek G, Laufer G, Grabenwöger F

Second Surgical Department, University of Vienna, Austria

Laser angioplasty and laser-assisted angioplasty have become a clinical reality. Producing sharply defined borders of the ablated area with minimal adjacent thermal damage, excimer lasers offer several proven and some potential advantages over conventional systems. To evaluate the feasibility of excimer laser angioplasty, we have treated one patient using 308-nm radiation via a bare fiber in direct contact with the total occlusion of a right femoral artery. The lesion was successfully recanalized, thus allowing easy passage of the balloon catheter and subsequent dilatation. This percutaneous laser recanalization of an occluded peripheral artery is one of the first to be done in man using excimer laser radiation, thus demonstrating that the technique is feasible and the system is potentially useful.

Lasers Surg Med. 1988;8(3):223-32Percutaneous, in vivo excimer laser angioplasty: results in two experimental animal modelsIsner JM, Gal D, Steg PG, DeJesus ST, Rongione AJ, Halaburka KR, Slovenkai GA, Clarke RH

Tufts University School of Medicine, Boston, Massachusetts

Pulsed ultraviolet light from an excimer laser was successfully transmitted via conventional fused silica optical fibers and used to accomplish recanalization of stenotic or totally occluded arteries in an intact, flowing blood field of two atherosclerotic animal models. The fibers, 300-600 micron in diameter, were delivered percutaneously in wire-guided multilumen catheters and then used to transmit wavelengths of 308 or 351 nm from excimer lasers with pulse durations of 12 nsec or less. Lesions from 70-100% diameter narrowing, and 0.6 to 5.5 cm in length were successfully recanalized (less than 50% residual diameter narrowing) in eight animals, using 3-4 J/cm2/pulse, 10-50 Hz, and 48-370-sec cumulative exposure. Necropsy examination in six of the eight animals disclosed no signs of thermal injury. Perforations were observed in four of eight animals. Thus, while use of an excimer laser power source did not obviate vascular perforation as a complication of laser angioplasty, these preliminary results indicate that energies of pulsed ultraviolet light sufficient to ablate atherosclerotic plaque can be both transmitted via conventional fused silica optical fibers and used successfully within an intact, flowing blood field. It may therefore be possible to use pulsed ultraviolet light from an excimer laser to accomplish percutaneous ablation of atherosclerotic arterial obstructions in humans.