Abstracts of Current Literature

VASCULAR

• Diagnosis

A Multicenter Randomized TrialComparing a Percutaneous CollagenHemostasis Device with Conven­tional Manual Compression afterDiagnostic Angiography and Angio­plasty. Timothy A. Sanborn, Harry H.Gibbs, Jeffrey A. Brinker, et al. JAm CollCardiol 1993; 22:1273-1279. (TAS., Car­diology Division, Starr 445, New YorkHospital-Cornell Medical Center, 525 E 68St, New York, NY 10021)

• Objectives. A new percutaneous colla­gen hemostasis device was compared withconventional compression techniques afterdiagnostic catheterization and angioplasty.Background. Peripheral vascular complica­tions after diagnostic catheterization ormore complex interventional procedures,as well as the discomfort of manual com­pression and prolonged bed rest, representsignificant morbidity for invasive cardiacprocedures. Methods. A prospective, multi­center, randomized trial was designed tocompare the hemostasis time in minutesand the incidence of vascular complica­tions in patients receiving a vascular he­mostasis device with those undergoingconventional compression techniques. Re­sults. After diagnostic catheterization, he­mostasis time was significantly less withthe vascular hemostasis device than withconventional manual compression (4.1minutes ± 2.8 [n = 90 patients] vs 17.6minutes ± 9.2 [n = 75], P < .0001). Thisdifference was greater in patients undergo­ing angioplasty and was unrelated to theanticoagulation status (4.3 minutes ± 3.7[n = 71 not receiving heparin], 7.6 min­utes ± 11.6 [n = 85 receiving heparin],33.6 minutes ± 24.2 [n = 134 control pa­tients not receiving heparin], P < .0001 vscontrol patients). The time from the startof the procedure to ambulation wasslightly less after diagnostic catheteriza­tion in patients treated with the device(13.3 hours ± 12.1 vs 19.2 hours ± 17.8,P < .05). It was also less in patients whounderwent angioplasty when the devicewas used after discontinuation of anticoa­gulation (23.0 hours ± 11.1, without hepa­rin), as compared with control compressiontechniques (32.7 hours ± 18.8, P < .0001).Time to ambulation was even shorter (16.1hours ± 11.1 hours, P < .0001) in patientsin whom the device was placed immedi-

ately after angioplasty while they werestill fully anticoagulated with a prolongedactivated clotting time (336 sec ± 85).There were no major complications (sur­gery or transfusion) after diagnostic cathe­terization, and there was a low incidenceof major complications in patients whounderwent angioplasty (0.7% in control pa­tients, 1.4% with the device without hepa­rin, 1.2% with the device and heparin,P = NS). After angioplasty, there was atrend toward fewer hematomas when thedevice was used in the absence of heparin(4.2% vs 9.7% in control patients, P =.14). Conclusions. A new vascular hemo­stasis device can significantly reduce thepuncture site hemostasis time and thetime to ambulation without significantlyincreasing the risk of peripheral vascularcomplications. The role of this technologyin reducing complications, length of hospi­tal stay, and cost remains to be deter­mined.AUTHORS' ABSTRACT

Quantitative Plasma D-dimer Levelsamong Patients Undergoing Pulmo­nary Angiography for SuspectedPulmonary Embolism. Samuel Z.Goldhaber, Grant R. Simons, C. GregoryElliott, et al. JAMA 1993; 270:2819-2822.(S.Z.G., Cardiovascular Division, Brighamand Women's Hospital, 75 Francis St, Bos­ton, MA 02215)

• Objective.-To test the hypothesis thata low D-dimer level has a high negativepredictive value for acute pulmonary em­bolism (PE) among patients undergoingdiagnostic pulmonary angiography. De­sign.-Blinded comparison of quantitativeplasma D-dimer levels, measured by usinga monoclonal antibody assay, with pulmo­nary angiographic results from 173 pa­tients with suspected acute PE. Setting.­Tertiary care setting at four participatinginstitutions. Patients.-Plasma sampleswere analyzed in 173 patients who under­went diagnostic pulmonary arteriographyfor suspected acute PE. Main OutcomeMeasures.-Sensitivity, specificity, andpredictive values of quantitative plasmaD-dimer levels for the diagnosis of PE,with pulmonary angiographic data as thecriterion standard test. Results.-Of 35 pa­tients with D-dimer values less than 500nglmL, only three had abnormal pulmo­nary angiograms. The negative predictivevalue of a plasma D-dimer level less than500 ng/mL for acute PE was 91.4% (95%confidence interval [Cl], 76.9%-98.2%). D-

dimer levels were greater than 500 nglmLin 42 of 45 patients with PE and in 96 of128 patients without PE (P = .016). Sensi­tivity, specificity, and positive predictivevalue of a plasma D-dimer level greaterthan 500 nglmL for acute PE were 93.3%(95% Cl, 81.7%-98.6%), 25.0% (95% Cl,17.50/0-32.5%), and 30.4% (95% Cl, 22.8%­38.1%), respectively. Conclusions.-The re­sults of our study indicate that quantita­tive plasma D-dimer levels can be usefulin screening patients with suspected PEwho require pulmonary angiography.Plasma D-dimer values less than 500 nglmL may obviate pulmonary angiography,particularly among medical patients forwhom the clinical suspicion of PE is low.The plasma D-dimer value, assayed byusing a commercially available enzyme­linked immunosorbent assay kit, is a sen­sitive but nonspecific test for the presenceof acute PE.AUTHORS' ABSTRACT

Management of Patients with Intra­mural Hematoma of the ThoracicAorta. Robert C. Robbins, Robert P.McManus, R. Scott Mitchell, et al. Circula­tion 1993; 88:1-10. (D. Craig Miller, De­partment of Cardiovascular and ThoracicSurgery, Falk Cardiovascular ResearchCenter, Stanford UniverBity School ofMedicine, Stanford, CA 94305)

• Background. Intramural hematoma ofthe thoracic aorta (lMH) is a diagnosis ofexclusion and represents spontaneous, lo­calized hemorrhage into the wall of thethoracic aorta in the absence of bona fideaortic dissection, intimal tear, or penetrat­ing atherosclerotic ulcer. This process mayarise from primary vasa vasorum hemor­rhage within the aortic media or ruptureof an atherosclerotic plaque. The clinicalpresentation of patients with IMH mimicsthat of acute aortic dissection; moreover,considerable diagnostic confusion existsdespite the use of many different imagingmodalities. The optimal mode of manage­ment of patients with IMH (medical vsmedical plus surgical) remains problematicbecause of the paucity of informationavailable. Methods and Results. Thirteenpatients with IMH were managed at twomedical centers between 1983 and 1992.Patients with IMH caused by giant pene­trating atherosclerotic ulcers were specifi­cally excluded. There were eight womenand five men (mean age, 70 years [range,54-82 years]). The admitting clinical diag­nosis was acute aortic dissection, and all

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March-April 1994

patients had a history of hypertension.There was no evidence of aortic dissectionor intimal disruption as assessed at com­puted tomography (CT) (n = 11), aortogra­phy (n = 10), magnetic resonance (MR)imaging (n = 9), transesophageal echocar­diography (TEE) (n = 6), or intravascularultrasound (n = 1). The diagnosis of IMHwas established by exclusion. The descend­ing thoracic aorta was involved in 10 casesand the ascending aorta or arch in three.Conservative medical management was at­tempted initially. All three patients withIMH involving the ascending aorta ulti­mately required operative intervention,and two individuals died; two of 10 pa­tients with descending aortic involvementeventually underwent surgery. Averagehospital stay was 11 days; the mean fol­low-up interval for discharged patientswas 29 months. Conclusions. IMH is a dis­tinct pathological entity, should not beconfused with aortic dissection, and proba­bly will be identified more frequently inthe future. All patients with IMH shouldbe monitored carefully and treated withaggressive antihypertensive therapy. Fre­quent serial assessment is necessary byusing TEE or MR imaging/CT. Based onthis small experience, patients with as­cending aorta or arch IMH, ongoing pain,or IMH expansion should probablyundergo early graft replacement. Patientswith IMH involving the descending tho­racic aorta who have no evidence of pro­gression and become pain free canprobably be treated conservatively but re­quire antihypertensive therapy and serialaortic imaging surveillance indefinitely.AUTHORS'ABSTRACT

Magnetic Resonance Volume Flowand Jet Velocity Mapping in AorticCoarctation. Raad H. Mohiaddin,Philip J. Kilner, Simon Rees, et al. JAmColl Cardiol1993; 22:1515-1521. (RH.M.,Magnetic Resonance Unit, Royal Bromp­ton National Heart and Lung Hospital,Sydney St, London SW3 6NP, England)

• Objectives. Nuclear magnetic reso­nance (MR) imaging velocity mapping wasused to characterize flow waveforms and tomeasure volume flow in the ascending anddescending thoracic aorta in patients withaortic coarctation and in healthy volun­teers. The authors present the method anddiscuss the relation between these mea­surements and aortic narrowing assessedat MR imaging. Finally, they comparecoarctation jet velocity measured with MR

imaging velocity mapping with that ob­tained from continuous wave Dopplerechocardiography. Background. Thedevelopment of a noninvasive imagingmethod for morphologic visualization ofaortic coarctation and for measurement ofits impact on blood flow is highly desirablein the preoperative and postoperativemanagement of patients. Methods. MRphase-shift velocity mapping was used tomeasure ascending and descending aorticvolume flow in 39 patients with aorticcoarctation and in 12 healthy volunteers.MR imaging was also used for anatomicand peak jet velocity measurements. Thelatter were compared with those availablefrom continuous wave Doppler study in40% of the patients. Results. Whereas as­cending aortic volume flow measurementdid not show significant differences be­tween the patient and healthy controlgroups, volume flow curves in the descend­ing aorta did show significant differencesbetween the two groups. Peak volume flow(mean ± SD) was 10.6 L/min ± 5.3 in pa­tients and 19.6 L/min ± 4.7 in controlsubjects (P < .001). Time-averaged flowwas 2.5 L/min ± 0.9 in patients and 3.9L/min ± 1.1 in control subjects (P < .05).The descending ascending aorta flow ratiowas 0.47 ± 0.19 in patients and 0.64 ±0.08 in control subjects (P < .05). Thesevariables correlate well with the degree ofaortic narrowing. Peak coarctation jet ve­locity measured with MR imaging velocitymapping is comparable to that obtainedfrom continuous wave Doppler study (r =.95). Conclusions. Normal ranges for vol­ume flow in the descending aorta anddemonstrated abnormalities in patientswith aortic coarctation were established.These abnormalities are likely to be re­lated to resistance to flow imposed by thecoarctation and could represent an addi­tional index for monitoring patients beforeand after intervention.AUTHORS' ABSTRACT

Dynamic Gadolinium-enhancedThree-dimensional Abdominal MRArteriography. Martin R Prince, E.Kent Yucel, John A. Kaufman, et al.JMRI 1993; 3:877-881. (M.RP., Depart­ment of Radiology, University Hospitals,B1D530, University of Michigan, 1500 EMedical Center Dr, Ann Arbor, MI 48109­0030)

• The abdominal aorta and renal, vis­ceral, and iliac arteries were evaluated in16 patients with three-dimensional Four-

ier transform imaging enhanced with ga­dopentetate dimeglumine. By imagingdynamically during the arterial phase of a5-minute injection (0.2 mmol!kg), highlysignificant (P < .0001) preferential arte­rial enhancement (signal-to-noise ratio ±standard deviation, 10 ± 0.9), with mini­mal enhancement of the inferior vena cava(5.1 ± 1.4) or background tissues (fat, 4.3± 0.7; muscle, 2.4 ± 0.5), was achieved inevery patient. In six patients with angio­graphic and/or surgical correlation, 10 of10 stenoses and two of two occlusions werecorrectly identified. No in-plane saturationor pulsatility artifact was identified in anyof the 16 patients. In conclusion, dynamicimaging during the injection of gadopen­tate dimeglumine is a promising techniquefor evaluation of the abdominal aorta andbranch vessels.AUTHORS' ABSTRACT

Aortoiliac Disease: Two-dimensionalInflow MR Angiography with LipidSuppression. Susan A. Mulligan, MarkDoyle, Tetsuya Matsuda, et al. JMRI1993; 3:829-834. (SAM., Radiology Asso­ciates of Birmingham, PC, 1920 Hunting­ton Rd, Birmingham, AL 35209)

• A magnetic resonance (MR) imagingstrategy, SLIP (spatially separated lipidpresaturation), which can be incorporatedinto existing MR imaging and MR angio­graphic techniques, has been developed tosuppress lipid signal. The authors reportthe clinical application of this technique,with a triple comparison of two-dimen­sional inflow MR angiography, with andwithout SLIP, and x-ray angiography inpatients with aortoiliac disease. SLIP im­proved visualization of arterial segments,with 50 of 63 (79%) arterial segments vis­ualized versus 41 of 63 (65%) for non-SLIPMR angiography. The SLIP strategy aidsin the depiction of slow or turbulent flow,because the lipid signal is suppressedwhile the intravascular signal is left un­disturbed. Image quality improves becauseof the combination of decreased back­ground lipid signal intensity and use or"the maximum-intensity-projection algo­rithm. Compared with x-ray arteriog­raphy, non-SLIP MR angiography had asensitivity and specificity of 60% and 56%,respectively, for detection of lesions with500/0-100% diameter reduction, while SLIPMR angiography had a sensitivity andspecificity, respectively, of 53% and 67%.AUTHORS' ABSTRACT

• Angioplasty, Atherectomy, Lasers

Redefining the Treatment of Periph­eral Artery Disease: Role of Percuta­neous Revascularization. Jeffrey M.Isner, Kenneth Rosenfield. Circulation1993; 88:1534-1557. (J.M.I., St. Elizabeth'sHospital, 736 Cambridge St, Boston, MA02135)

• This is an opinion paper and reviewarticle by two cardiologists. In the wordsof the authors, the "purpose of this articleis to make explicit the fact that availabil­ity of effective alternative therapy,namely, percutaneous revascularization,permits a lower threshold for interventionfor patients with PAD [peripheral arterydisease] than has been traditionally prac­ticed." The authors review studies of phar­macologic and exercise therapy, andconclude that, in patients with "disablingsymptoms and anatomic findings favorablefor PTA [percutaneous transluminal angio­plasty]," PTA is often indicated. The au­thors then consider PAD in the followingregions of interest: aortoiliac, femoral pop­liteal, crural, and bypass grafts. In eachregion of interest, indications for treat­ment, short-term and long-term clinical re­sults, and technical considerations withrespect to recanalization devices andstents are considered. The authors thendiscuss the cost-effectiveness of percuta­neous revascularization procedures. In par­ticular, articles by Doubilet and Abrams(1984) and Tunis et al (1991), along witharticles stimulated by them, are reviewed.DAVID M. WILLIAMS, MDUniversity HospitalsAnn Arbor, Mich

Vascular Complications after Bal­loon and New Device Angio-plasty. Jeffrey J. Popma, Lowell F.SaUer, Augusto D. Pichard, et al. Circula­tion 1993; 98:1569-1578. (J.J.P., Angio­graphic Core Laboratory, WashingtonHospital Center, 110 Irving St, Suite 4-B­1, Washington, DC 20010)

• Background. Despited their potentialadvantages, new coronary angioplasty de­vices may be associated with more fre­quent vascular complications than notedafter standard balloon angioplasty, theo­retically due to the larger sheaths and pro­longed periods of anticoagulation requiredby some of these devices. This studysought to identify the incidence, predic­tors, and clinical outcome of vascular com-

plications after new device angioplasty.Methods and Results. The clinical courseof 1,413 patients was reviewed after bal­loon or new device angioplasty. Vascularcomplications were defined as formation ofa pseudoaneurysm, arteriovenous fistula,retroperitoneal hematoma, or groin hema­toma associated with a hematocrit dropgreater than 15 points or the need for sur­gical repair. Stepwise logistic regressionwas used to identify independent predic­tors for vascular complications. Vascularcomplications developed after 84 (5.9%)procedures; they occurred more frequentlyafter intracoronary stenting (14.0%) andextraction atherectomy (12.5%) than afterballoon angioplasty (3.2%) (odds ratios,4.86; P < .001, and 4.26, P < .05, respec­tively). Independent predictors of vascularcomplications included the use of intrapro­cedural thrombolytic agents (P < .01),intracoronary stenting (P < .005), or ex­traction atherectomy (P < .05); high maxi­mum creatinine level (P < .005); low nadirplatelet count (P < .001); longer periods ofexcess anticoagulation (P < .05); and theneed for repeat coronary angioplasty (P <.005). Vascular complications were not re­lated to the size of the arterial sheathused. Conclusions. Vascular complicationsdeveloped more frequently after new de­vice angioplasty than after balloon angio­plasty, with the risk for vascularcomplications directly related to the de­gree of periprocedural anticoagulation.AUTHORS' ABSTRACT

Angiographic-Pathologic Correla­tions after Elective PercutaneousTransluminal Coronary Angio­plasty. Takahiko Naruko, Makiko Ueda,Anton E. Becker, et al. Circulation 1993;88:1558-1568. (A.E.B., Department of Car­diovascular Pathology, Academic MedicalCenter, Meibergdreef 9, 1105 AZ Amster­stam-ZO, The Netherlands)

• Background. The local effect of coro­nary angioplasty is evaluated on the basisof postangioplasty angiograms. Smooth­walled dilatation is considered to representminimal or no injury, whereas intralumi­nal haziness corresponds with walilacera­tion. This study correlates the preangio­plasty and postangioplasty angiogramswith the histopathology of the target sites.Methods and Results. The study includes12 patients, each undergoing an electiveprocedure, and covers 19 angioplasty sites.Smooth-walled dilation and intraluminalhaziness were not mutually exclusive. The

Abstracts • 397Volume 5 Number 2

angiograms were interpreted as smooth­walled dilation (n = 3), smooth-walled di­lation with intraluminal haziness (n = 4),intraluminal and extraluminal haziness (n

= 5), extraluminal dissection (n = 5), spi­ral-type dissection (n = 1), and aneurysm(n = 1). The histology of the arterial seg­ments revealed wall laceration in all.Smooth-walled dilation without intralumi­nal haziness correlated with lacerationlimited to the intima in two, but with me­dial injury in one. Smooth-walled dilationwith intraluminal haziness correlated withlaceration limited to the intima in two andwith medial injury in two. Intraluminaland extraluminal haziness correspondedwith extensive laceration with deep in­volvement of the media in each. Extralu­minal dissection correlated with adissection along the shoulder area of theplaque, creating a broad-based flap. Thespiral-type dissection corresponded with atrue dissection into the plaque-free media.The aneurysm correlated with partialwashout of an atherosclerotic plaque. Con­clusions. The angiographic image of intra­luminal and extraluminal hazinessindicates extensive medial laceration.Smooth-walled dilation, with or withoutintraluminal haziness, is not a reliable in­dicator. The study emphasizes the need toreconsider the interpretations of postangio­plasty coronary angiograms.AUTHORS' ABSTRACT

• Cardiac

Transcatheter Occlusion of PatentDuctus Arteriosus with GianturcoCoils. Thomas R. Lloyd, Raymond Fed­derly, Alan M. Mendelsohn, et al. Circula­tion 1993; 88:1412-1420. (T.R.L., PediatricCardiology, UMMC, F1310 MCHC, Box0204, Ann Arbor, MI 48108-0204)

• Background. Transcatheter occlusionwith Gianturco coils has been attemptedin a small number of patients with tiny (s1.5-mm diameter) patent ductus arterio­sus, and preliminary results have been en­couraging. This study extends this methodto larger ductus sizes and makes recom­mendations for proper coil size selection.Methods and Results. Coil occlusion wasattempted in 24 consecutive patients withpatent ductus arteriosus who did not re­quire other cardiac surgery. Median pa­tient age was 4.2 years (8 months to 30years), and mean ductus diameter was 1.7mm ± 0.8. Two instances of coil emboliza-

398 • Journal of Vascular and Interventional Radiology

March-April 1994

tion occurred in the first four patients,with successful coil retrieval. Based onthis experience, the authors proposed thatthe coil helical diameter should be twice ormore the minimum ductus diameter, withcoil length sufficient for three or moreloops. With these recommendations, coilswere successfully implanted in the subse­quent 20 consecutive patients. Of the 22patients with successful coil implantation,15 (68%) had no residual shunting, andseven had trace residual shunting atangiography. The continuous murmur wasabolished in all 22 patients. No significantcomplications occurred, and all patientswere discharged within 24 hours of suc­cessful coil implantation. No change in thesystolic pressure gradient between mainand left pulmonary artery or ascendingand descending aorta was observed. Con­clusions. Transcatheter occlusion of patentductus arteriosus can be safely and effec­tively achieved in patients with ductus di­ameters up to 3.3 mm. Coil occlusion doesnot cause obstruction to flow in the leftpulmonary artery or descending aorta.Coils should be selected to provide a heli­cal diameter twice or more the minimumductus diameter and a length sufficient forthree or more loops.AUTHORS' ABSTRACT

• IVC Filters

Potential of Overuse of the InferiorVena Cava Filter. Thomas E. Arnold,Vasilios D. Karabinis, Vinod Mehta, et al.Surg Gynecol Obstet 1993; 177:463-467.(Morris D. Kerstein, Hahnemann Univer­sity School of Medicine, Department ofSurgery, Broad and Vine Sts, Ms No 413,Philadelphia, PA 19102-1192)

• To examine indications for, and mor­bidity and mortality rate of, inferior venacava filter insertion at a community hospi­tal, the records of 69 patients who receivedinferior vena cava filters were reviewed.Patients were assigned to three groups­group I, 45 patients with pulmonary em­bolism or deep venous thrombosis and acontraindication to anticoagulation; group2, 14 patients with a diagnosis as in groupI, who received filters without considera­tion to anticoagulation, and group 3, 10patients with clinically suspected deep ve­nous thrombosis and no objective assess­ment of the process. Indications for filterplacement were recorded. Morbidity andin-hospital mortality rates were 29% and

49%, 43% and 36%, and 10% and 30% forgroups I, 2, and 3, respectively (29% and43% overall). Only patients in group 1 haddocumented indications for caval interrup­tion. Results compared unfavorably withcomplication and mortality rates reportedpreviously. Nonselective use of inferiorvena cava filters is associated with unac­ceptable morbidity and mortality rates.Strict indications for filters must be welldocumented.AUTHORS' ABSTRACT

• Vascular Surgery

The Continuing Challenge of Aneu­rysms of the Popliteal Artery. AntonRoggo, Urs Brunner, Leslie W. Ottinger,et al. Surg Gynecol Obstet 1993; 177:565 ­572. (L.W.O., Massachusetts General Hos­pital, 15 Parkman St, Suite 465, Barton,MA 02114)

• This report is an analysis of 252 pop­liteal artery aneurysms (PAA) in 167 pa­tients treated surgically at the UniversityHospital in Zurich during a 27-year periodfrom 1965 to 1991. The predominance ofmale patients (95%) was consistent withthat of other reports. PAA were bilateralin 51% of the patients and were associatedwith aneurysms at other sites in 38%.Atherosclerosis was by far the most com­mon cause (98%). PAA were symptomaticin 75% of the patients, the predominantfindings being ischemia from emboli,thrombosis, or rupture. Primary amputa­tion was required in 23 extremities. Sur­gical reconstruction with bypass wasperformed for 229 PAA. A secondary am­putation was necessary in 18 limbs. Therisk of complications from popliteal aneu­rysm, and the good results from surgicaltreatment suggest that a revascularizationprocedure in the asymptomatic stageshould be recommended unless specificcontraindications exist. The authors con­clude that surgical treatment should beperformed in symptomatic and asympto­matic PAA larger than 2 em in diameter.Long-term results of surgical reconstruc­tion are improved if an autogenous sa­phenous vein is used and if reconstructionis performed before the occurrence ofcomplications. Polytetrafluoroethyleneprostheses should be used when an autolo­gous saphenous vein is not available. Theuse of Dacron (polyester fiber) grafts is nolonger indicated.AUTHORS' ABSTRACT

• Stents

The Use of the Wallstent in Aorto­lliac Vascular Disease. J. F. Dyet,J.W. Shaw, A. M. Cook, et a1. Clin Radial1993; 48:227-231. (J.F.D., Department ofRadiology, Hull Royal Infirmary, AnlabyRd, Hull HU3 2JZ, UK)

• Forty-three patients underwent inser­tion of self-expanding endovascular Wall­stents for aorto-iliac arterial disease. A to­tal of 59 Wallstents were inserted into 50iliac arteries. There were 27 males and 16females with a mean age of 62.5 years. In­cluded in the series were 19 iliac occlu­sions, 21 severe atheromatous disease ofthe aorto-iliac segment, two severe dissec­tions following conventional angioplasty,and one restenosis of a previously dilatediliac segment. All of the stents were suc­cessfully deployed but there were five sig­nificant complications. One case of distalembolism was treated with surgical embo­lectomy but the other four were treatedwith an additional percutaneous tech­nique. At follow-up after 6 months all pa­tients remain symptomatically improved.Aorto-iliac stenting is a cost-effectivetreatment in selected cases of severe aorto­iliac disease.AUTHORS' ABSTRACT

The Use of Endovascular Tech­niques for the Treatment of Compli­cations of Aortic Dissection. PhilipJ. Walker, Michael D. Dake, R. ScottMitchell, et a1. J Vase Surg 1993;18:1042-1051. (D. Craig Miller, Depart­ment of Cardiovascular and Thoracic Sur­gery, Folk Cardiovascular ResearchCenter, Stanford University School ofMedicine, Stanford, CA 94305-5247)

• Intravascular ultrasonography (US),balloon angioplasty, stent placement, andendovascular septal fenestration have beenused in the evaluation and treatment ofvascular complications of acute andchronic aortic dissection in five patients.There were three men and two womenwith an average age of 52 years (range,39-64 years). There were three chronictype A dissections, one acute type B, andone subacute type B dissection. Intravas­cular US was used in all five cases. Thethree patients with chronic type A dissec­tions underwent unilateral renal arteryangioplasty (RA PTA) and stent place­ment; one patient with an acute type Bdissection and associated fibromusculardysplasia underwent bilateral RA PTA

without stent placement. These procedureswere performed to ameliorate severe hy­pertension. The final patient, with a sub­acute type B dissection, underwent iliacartery stent placement to correct severelower extremity ischemia. During a secondintervention, this patient, who also hadbowel ischemia and nonresolving acuterenal failure, underwent balloon dilationof a preexisting septal fenestration to aug­ment visceral blood supply and bilateralRA PTA and stent placement in an effortto improve renal function. This patienteventually died of gut ischemia. After RAPTA and stent placement, one patient hada major intrarenal hemorrhage that re­quired coil embolization and transfusion.In the four survivors, RA PTA and stentplacement resulted in immediate improve­ment in blood pressure control. This re­sponse has been sustained during follow­up intervals ranging from 8 to 18 months(average, 10 months). Intravascular UScan clearly demonstrate the pathologicanatomy associated with aortic dissection(even when angiography is ambiguous)and is essential for guiding therapeutic en­dovascular interventions. Further explora­tion of the efficacy of these endovasculartechniques is warranted in this high-riskgroup of patients with aortic dissectionwho have appropriate clinical indications.AUTHORS' ABSTRACT

Transluminal Placement of a Pros­thetic Graft-Stent Device for Treat·ment of Subclavian ArteryAneurysm. James May, GeoffreyWhite, Richard Waugh, et al. J Vasc Surg1993; 18:1056-1059. (J.M., Department ofSurgery, University of Sydney, NSW 2006Australia)

• A 78-year-old man was seen with anexpanding 5-cm false aneurysm of theright subclavian artery. This was treatedwith an intraluminal graft-stent device in­troduced through the brachial artery via a16-F sheath. The graft was constructedfrom two polytetrafluoroethylene patchesof O.4-mm thickness and anchored in thesubclavian artery by an 8-mm stainlesssteel stent. The procedure was monitoredwith an image intensifier. Completion ar­teriography and postoperative duplex scan­ning confirmed normal flow through thesubclavian artery with no communicationbetween the lumen and the aneurysmalsac. The patient recovered without compli­cation.AUTHORS'ABSTRACT

Clinical and Angiographic Outcomesafter Coronary Artery Stenting forAcute or Threatened Closure afterPercutaneous Transluminal Coro­nary Angioplasty: Initial Resultswith a Balloon-Expandable, Stain­less Steel Design. James A. Hearn,Spencer B. King III, John S. Douglas, Jr,et al. Circulation 1993; 88:2086-2096.(S.B.K., F-606 Emory University Hospital,1364 Clifton Rd, NE, Atlanta, GA 30322)

• Background. Acute occlusion after bal­loon coronary angioplasty is associatedwith an increased risk of angina, emer­gency coronary artery bypass grafting(CABG), myocardial infarction (MI), anddeath. Stents offer a way of restoring pat­ency and avoiding these complications.Methods and Results. One hundred sixteenpatients underwent attempted stent place­ment for imminent or total acute closureafter PTCA. In 103 patients (110 stents,105 procedures) the stent was successfullydeployed (89%). Angiographic success (fi­nal diameter stenosis of <50%) wasachieved in 94 placements (85%). Seventy­one phase 2 procedures (CABG optional,n = 96; phase I, CABG required, n = 9)were angiographically successful withoutcomplications of death, Q-wave myocardialinfarction, or CABG (clinical success,74%). Stent placement was associated withresolution of ST-segment deviation and an­gina in 84% of patients. Five deaths andfive Q-wave MIs occurred during hospitali­zation. Two deaths were related to pulmo­nary insufficiency from chronic lungdisease, and one patient died after rescuestent placement for left main coronary ar­tery occlusion during routine angiography.Another patient died after CABG was fol­lowed by right ventricular MI. The lastdeath occurred in an elderly patient whosuffered a stroke while on intravenousheparin. During hospitalization nine pa­tients developed reocclusion after stentplacement (8.6% of procedures) and sixunderwent repeat PTCA. CABG was per­formed after 29 stent procedures (28%).The first nine patients underwent CABGas a mandate of the phase 1 protocol. Inaddition, nine patients underwent CABGafter stenting with a good angiographic re­sult but with a large amount of myocar­dium at risk. Clinical follow-up wasobtained in all patients at a median of 14months (range, 2-43 months). There werethree late deaths (3%), two Q-wave myo­cardial infarctions (2%), 16 repeat PTCAs(16%), and 15 CABG procedures (15%).Angiographic restenosis (diameter, ~50%)

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Volume 5 Number 2

by using caliper measurements was foundin 30 of 57 patients (53%) at a median of 4months (93% of patients eligible). A totalof 41 procedures were successful and unac­companied by death, emergency or electivecoronary artery bypass grafting, or angio­graphic restenosis in follow-up. Restenosisand/or clinical events (death, MI, CABG,repeat PTCA) were associated with non-QMI, hypertension, diabetes, left circumflexcoronary artery stenting, saphenous veingraft stenting, smaller caliber arterystenting, higher balloon to artery ratios,and shorter inflation times. Conclusions.Coronary artery stenting for acute closureafter PTCA relieves myocardial ischemiaand provides an alternate means of treat­ment. This series includes early learningcurve experience; 70% (67 of 96) of pa­tients were spared CABG surgery whenthis adverse outcome occurred. Certainclinical and angiographic subsets are atincreased risk for restenosis and futurecardiac events.AUTHORS' ABSTRACT

Fate of Lesion-related Side Branchesafter Coronary Artery Stenting.David L. Fischman, Michael P. Savage,Martin B. Leon, et al. J Am Call Cardiol1993; 22: 1641-1646. (D.L.F., JeffersonMedical College, Suite 403, 1025 WalnutSt, Philadelphia, PA 19107)

• Objectives. The aim of this study wasto assess the immediate and long-termpatency of lesion-associated side branchesafter coronary artery stenting. Back­ground. The possible adverse effects re­lated to implantation of coronary stentsare not completely known. An importantpotential complication of stenting is sidebranch occlusion due to mechanical ob­struction or thrombosis. Methods. Serialcoronary angiography was performed in153 patients (167 lesions) at baseline, afterconventional balloon angioplasty, immedi­ately after Palmaz-Schatz stent placement,and at 6 months. The patency of sidebranches, where present, was analyzed ateach of these points. Results. Of 167 le­sions stented, 57 stent placements spanned66 side branches with a diameter of 1 mmor greater. Twenty-seven (41%) of theseside branches had ostial stenosis of 50% orgreater before standard balloon angio­plasty. Six side branches became occludedafter standard balloon angioplasty and re­mained occluded after stenting. Of the 60side branches patent after conventionalangioplasty, 57 (95%) remained patent illl-

400 . Journal of Vascular and Interventional Radiology

March-April 1994

mediately after stenting. All three sidebranches that became occluded after stent­ing had 50% or greater ostial stenosis atbaseline. All 60 side branches, includingthe three initially occluded after stenting,were patent at 6-month follow-up. Conclu­sions. These findings demonstrate that1) acute side branch occlusion due to coro­nary stenting occurs infrequently; 2) whenside branch occlusion occurs, it is associ­ated with intrinsic ostial disease; and3) the patency of side branch ostia is wellmaintained at long-term follow-up.AUTHORS' ABSTRACT

CHEST

Silicone Stents in the Managementof Inoperable TracheobronchialStenoses: Indications and Limita­tions. Chris T. Bolliger, Rudolf Probst,Kurt Tschopp, et al. Chest 1993; 104:1653­1659. (C.T.B., Respiratory Division, Uni­versity Hospital, 4031 Basel, Switzerland)

• Background: Various stent modelshave been developed for the treatment ofinoperable stenoses of the central airwayscaused by external compression. Increas­ing use is made of the silicone stents de­signed by Dumon. The authors testedtechnical feasibility, tolerance, and long­term efficacy of the stents in relieving res­piratory symptoms in patients referred forendoscopic palliation of malignant disease.Methods: All procedures were performedunder general anesthesia with the use ofthe rigid bronchoscope. Thirty-eight stentswere inserted in 31 patients (median age,67 years; 25 men and six women) whoseairways showed greater than 50% residualobstruction of the lumen after laser resec­tion of endobronchial tumor and/or me­chanical dilation of extrinsic compressions.Results: Stent placement and removal­where necessary-were easy in all pa­tients, but five stents inserted in three pa­tients with short (:;;2.5 cm) and conicalstenoses migrated, necessitating emer­gency removal. In 27 of the remaining 28patients, stent tolerance was excellent; oneproximal tracheal stent « 1 cm below thevocal cords) had to be removed because ofotalgia and dysphagia. One lethal hemop­tysis occurred within hours after a re­peated laser therapy and removal of an

indwelling stent. No other serious compli­cations occurred. Immediate and lastingrelief of dyspnea and improvements in per­formance status (Karnofsky scale, activityindex) were achieved in 90% (28 of 31) ofpatients (P < .01). The influence of adju­vant radiation therapy on local tumor re­currence and survival was analyzed in asubgroup of 10 patients with stage IIIBsquamous cell carcinoma with comparableperformance status. Five did not undergoadjuvant radiation therapy (group A) andfive did (group BJ. In group A, four of fivestents were occluded by tumor recurrenceabove or below the stent after a medianfollow-up of 2 months; in group B, zeroof five were occluded (P < .05) after 4months. Median survival was 4 months ingroup A and 6 months in group B; the dif­ference did not reach significance. Conclu­sions: The silicone stents designed byDumon are easily inserted and removed;they are also well tolerated and very effi­cacious in relieving respiratory symptomscaused by extrinsic airway compression.Short and conical stenoses present limita­tions for their use due to increased risk ofmigration. Combined treatment with laserresection, stent insertion, and subsequentradiation therapy is necessary to preventlocal tumor recurrence and may improvesurvival.AUTHORS' ABSTRACT

Lung Abscess: Percutaneous Cathe­ter Therapy. H. K Ha, M. W. Kang, J.M. Park, et al. Acta Radiol 1993; 34:362­365. (H.KH., Department of Radiology,Kangnam St. Mary's Hospital, CatholicUniversity Medical College, 505 Banpo­Dong, Socho-Gu, Seoul 137-701, Korea)

• Lung abscess was successfully treatedwith percutaneous drainage in five of sixpatients. Complete abscess resolution oc­curred in four patients, partial resolutionin one, and no response in one. The dura­tion of drainage ranged from 7 to 18 days(mean, 15.5 days) in successful cases. Thefailure of drainage in one neurologicallyimpaired patient was attributed to persist­ent aspiration. In two patients, concurrentpleural empyema was also cured. CT pro­vided the anatomic details necessary forchoosing the puncture site and avoidingpuncture of the lung parenchyma. Percuta­neous catheter drainage is a safe and ef­fective method for treating lung abscess.AUTHORS' ABSTRACT

GASTROINTESTINAL

A Controlled Trial of an ExpansileMetal Stent for Palliation of Esopha­geal Obstruction due to InoperableCancer. Klaus Knyrim, Hans-JoachimWagner, Norbert Bethge, et al. N Engl JMed 1993; 329:1302-1307. (KK, Medizin­ische Klinik I, Stiidtische Kliniken, Mon­chebergstrasse 41, 3500 Kassel, Germany)

• Background. Esophageal obstructiondue to cancer can produce debilitating dys­phagia. Rapid palliation is usually possiblewith endoscopic placement of a plasticesophageal prosthesis, but this device hasa high rate of complications. A new alter­native is a metal-mesh stent that collapsesto 3 mm in diameter at placement but canthen expand up to 16 mm. Methods. Pa­tients with esophageal carcinoma (39 pa­tients) or malignant extrinsic obstruction(three patients) were randomly assigned totreatment with either a plastic prosthesis(16 mm in diameter) or an expansilemetal-mesh stent. The patients were eval­uated every 6 weeks until death. The de­gree of palliation was expressed as adysphagia score and a Karnofsky perform­ance score. Results. Complications weresignificantly less frequent with the metalstents than with the plastic prostheses (nocomplications vs nine; P < .001). The dys­phagia and Karnofsky scores improved sig­nificantly and to a similar degree in bothtreatment groups. The most commoncauses of recurrent dysphagia were migra­tion of the plastic prostheses (five patients)and ingrowth or overgrowth of the metalstents by tumor (five patients). The ratesof reintervention were similar in bothtreatment groups, as were the 30-day mor­tality rates. The period of hospitalizationafter placement of a prosthesis was signifi­cantly longer in the group given plasticprostheses than in the group given metalstents (mean ± SE, 12.5 days ± 2.1 vs 5.4days ± 1.0 (P = .005). Despite theirhigher initial cost, the metal stents werecost-effective because of the absence of fa­tal complications and the decrease in thehospital stay. Conclusions. Expansilemetal stents are a safe and cost-effectivealternative to conventional plastic endo­prostheses in the treatment of esophagealobstruction due to inoperable cancer.AUTHORS' ABSTRACT

HEPATOBILIARY

Effects of Preoperative Transcath·eter Hepatic Arterial Chemoemboli­zation for Hepatocellular Carci·noma: The Relationship betweenPostoperative Course and TumorNecrosis. Eisuke Adachi, Takashi Mat­sumata, Takashi Nishizaki, et al. Cancer1993j 73:3593-3598. (Masazumi Tsune­yoshi, Second Department of Pathology,Faculty of Medicine, Kyushu University,3-1-1, Maidashi, Higashi-ku, Fukuoka 812,Japan)

• Background. The effects of preopera­tive transcatheter arterial chemoemboliza­tion (TAE) for hepatocellular carcinoma(HCC) remain a matter of controversy.Methods. Seventy-two patients with HCCwere entered in the studyj the patients didnot have the risk factors for disease recur­rence of tumor larger than 5 cm in diame­ter, the presence of venous invasion, orintrahepatic metastasis. Only patientswith 3 years of follow-up after curative re­section were selected. Forty-six underwentTAE (group 1) and 26 did not undergoTAE (group m. Group I was divided intothree subgroups according to the degree oftumor necrosis: IA, complete necrosis; IB,partial necrosisj and IC, no necrosis.Group II was divided into two subgroups:IIB, partial necrosisj and IIC, no necrosis.Results. Preoperative TAE did not improvethe average disease-free survival rates ofthe group as a whole. For patientsundergoing TAE, the survival rate ofgroup IB was significantly worse than thatof groups IA or IC. The survival rate ofgroup IB was worse than that of group II,but the difference was not significant. Ingroup II, the survival of group IIB wasworse than that of group IIC. Histologi­cally, residual tumor cells lacking mutualcontact were detected in some patients ingroup IB. Conclusion. These results indi­cate that partial tumor necrosis caused bypreoperative TAE or spontaneous tumornecrosis per se might facilitate postopera­tive disease recurrence. This may occur be­cause in patients with partial necrosis, theremaining tumor cells are less firmly at­tached and more likely to be dislodged intothe bloodstream during hepatic resection.AUTHORS' ABSTRACT

Postmortem Survey of Bile Duct Ne·crosis and Biloma in HepatocellularCarcinoma after Transcatheter Arte·rial Chemoembolization Therapy:Relevance to Microvascular Dam·ages of Peribiliary CapillaryPlexus. Satoshi Kobayashi, YasuniNakanuma, Tadashi Terada, et al. Am JGastroenterol 1993j 88:1410-1415. (Y.N.,Second Department of Pathology, Kana­zawa University School of Medicine, Kana­zawa 920, Japan)

• The study was aimed at determiningthe incidence of bile duct necrosis and bil­oma in hepatocellular carcinoma (HCC)after transcatheter arterial embolizationtherapy (TAE) or hepatic arterial infusionchemotherapy (HAl), and also clarifyingthe relationship between these duct inju­ries and the peribiliary capillary plexus(PBP). These bile duct injuries were foundin seven (12.5%) of the 56 consecutive au­topsy livers with HCC and a history ofTAE or HAl, whereas they were not in the48 consecutive autopsy livers with HCCbut without such a history (P <.02). Therewas a close relation between the areas ofTAE and bile duct injuries. These compli­cations were restricted to the intrahepaticlarge or septal bile ducts. The inner layervessels of PBP were considerably reducedin the HCC cases with a history of TAE orHAl, irrespective of these bile duct inju­ries. The authors concluded that bile ductnecrosis or biloma was not uncommon incirrhotic livers with HCC after TAE orHAl, and that TAE or HAl might causethe reduction of the inner layer vessels ofPBP which may be necessary but was in­sufficient for the induction of bile duct ne­crosis or biloma.AUTHORS' ABSTRACT

Stability Studies on Chemoemboliza·tion Mixtures: Dialysis Studies ofDoxorubicin and Lipiodol with Avi·tene, Gelfoam, and Angiostat.Daniel Struk, Richard N. Rankin, StephenJ. Karlik. Invest Radiol 1993j 28:1024­1027. (S.J.K., Department of DiagnosticRadiology, University Hospital, PO Box5339, London, Ontario N6A 5A5, Canada)

• Rationale and Objectives. Chemoem­bolization, with a combination of embolicand chemotherapeutic agents, appears tobe an effective treatment for hepatocellu­lar carcinoma. Although the postulatedmechanism of effectiveness hinges on aprolonged drug delivery, increasing evi-

Abstracts • 401Volume 5 Number 2

dence suggests that embolization mixturesare not stable. The objective of this studywas to investigate examples of these mix­tures. Methods. Dialysis techniques havebeen used to examine the pharmacokineticproperties of chemoembolization mixturesthat contain doxorubicin, Lipiodol (Guer­bet Products, Montreal, Quebec), and theembolizing agents Avitene (Alcon Labora­tories, Fort Worth, Texas), Gelfoam (Up­john, Kalamazoo, Mich), and Angiostat(Regional Therapeutic, Pacific Palisades,Calif). Results. Lipiodol, Gelfoam, and Avi­tene, when combined with doxorubicin,had only a small effect on the diffusion ofthe drug when compared with the diffu­sion curve of doxorubicin alone. Gelfoamor Avitene produced a thrombus-like con­sistency when added to a doxorubicinlLi­piodol combination, and an additionaldecrease in the doxorubicin appearancerate was observed. However, after 6 hours,doxorubicin levels for theses mixturesreached control values observed in 3hours. Angiostat without Lipiodol pro­duced a profound concentration-dependentdecrease in the diffusion of doxorubicin.After 9 hours, only 23% of the doxorubicinhad been released. Conclusion. The strongcomplexing ability of the embolic agentAngiostat may enable it to be a carrier fordoxorubicin and surpass other mixturescurrently employed for transcatheterchemoembolization.AUTHORS' ABSTRACT

GENITOURINARY

The Natural History of Renal An·giomyolipoma. Mitchell S. Steiner,Stanford M. Goldman, Elliot K. Fishman,et al. J Urol1993j 150:1782-1786. (Fromthe Departments of Urology and Radiol­ogy, Johns Hopkins University School ofMedicine, James Buchanan Brady Uro­logical Institute, Johns Hopkins Hospital,Baltimore, Maryland)

• Of 35 patients with 48 angiomyolipo­mas, 24 patients were followed up clini­cally to determine the natural history ofangiomyolipoma. Average patient age atpresentation was 50 years (range, 17-74years), and of the patients 94% werewomen, 17% had tuberous sclerosis, and25% overall had bilateral disease. The pa­tients could be divided into two distinctgroups based on tumor size of 4 cm or less

402 • Journal of Vascular and Interventional RadiologyMarch-April 1994

and greater than 4 cm. Those with tumorsless than 4 cm were less likely to be symp­tomatic (24%), and patients with angiomy­olipomas greater than 4 cm were moreoften symptomatic (52%). No surgery wasrequired for tumors less than 4 cm, but for30% of the tumors greater than 4 cm sur­gical intervention was necessary. Unlikeany previously reported large series, thisstudy included radiological and historicalfollow-up available for 24 patients withangiomyolipoma with a mean follow-up of4 years (range, 0.5-14 years). Moreover,the authors describe what they believe isthe first report of documented growth dur­ing the study period of 27% of angiomyoli­pomas less than 4 cm (four of 15 tumors)and 46% of angiomyolipomas greater than4 cm (six of 13 tumors). All patients withtumors less than 4 cm were more fre­quently symptomatic (46%) and requiredsurgery (54%). Patients with tuberous scle­rosis and angiomyolipomas were distinctlydifferent from patients with angiomyoli­poma only, since they tended to present ata younger age, had a higher incidence ofbilateral renal involvement, were moresymptomatic, had larger tumors that weremore likely to grow, and frequently re­quired surgery. Based on this study, amodified approach to the current manage­ment of angiomyolipoma is recommended.AUTHORS' ABSTRACT

NEUROINTERVENTIONAL

Evaluation of Pressure Changes inFeeding Arteries during Emboliza­tion of Intracerebral ArteriovenousMalformations. Takashi Handa, Mak­oto Negoro, Shigeru Miyachi, et al. J Neu­rosurg 1993; 79:383-389. (T.H., Depart­ment of Neurosurgery, Nagoya UniversitySchool of Medicine, 65 Tsuruma-cho,Showa-ku, Nagoya 466, Japan)

• The pressure in 47 arteries feeding 21arteriovenous malformations (AVMs) was

arteriovenous malformations (AVMs) wasinvestigated during transarterial emboli­zation with a Tracker-18 microcatheter.On average, systolic pressure increased by22 mm Hg. In AVMs with single or fewfeeders, embolization was usually achievedwell; in contrast, giant AVMs with multi­ple feeders and a large arteriovenousshunt were poorly embolized. However,large AVMs with well-demarcated compo­nents may be reduced by embolization toan appropriate size for surgery or stereo­tactic radiation therapy. It was found thatthe feeding artery pressure increased sig­nificantly more in well-embolized than inpoorly embolized cases. Measurement ofthe feeding artery pressure clarified thehemodynamics of AVMs and facilitatedmore successful embolization.AUTHORS' ABSTRACT

Role of Angiography FollowingAneurysm Surgery. R. Loch Mac­Donald, M. Christopher Wallace, John R.W. Kestle. J Neurosurg 1993; 79:826-832.(M.C.W., Division of Neurosurgery, De­partment of Surgery, 2-427 McLaughlinPavilion, Toronto Hospital, Western Divi­sion, 399 Bathurst St, Toronto, OntarioM5T 2S8, Canada)

• The postoperative angiograms in 66patients who underwent craniotomy forclipping of 78 cerebral aneurysms were re­viewed. Indications for urgent postopera­tive angiography included neurologicaldeficit or repeat subarachnoid hemorrhage.Routine postoperative angiograms werecarried out in the remaining patients.Postoperative angiograms were reviewedto determine the incidence of unexpectedfindings such as unclipped aneurysms, re­sidual aneurysms, and unforeseen majorvessel occlusions. Logistic regressionanalysis was used to test if the followingwere factors that predicted an unexpectedfinding on postoperative angiography:aneurysm site or size; the intraoperativeimpression that residual aneurysm wasleft or a major vessel was occluded; intra­operative aneurysm rupture; opening or

needle aspiration of the aneurysm afterclipping; or development of a new neuro­logical deficit after surgery. Kappa valueswere calculated to assess the agreementbetween some of these clinical factors andunexpected angiographic findings. Unex­pected residual aneurysms were seen inthree (4%) of the 78 occlusions. In addi­tion, three aneurysms were completely un­clipped (4%); these three patients werereturned to the operating room and hadtheir aneurysms successfully obliterated.There were nine unexpected major vesselocclusions (12%); six of these resulted indisabling stroke and two patients died. Ofsix major arteries considered to be oc­cluded intraoperatively and shown to beoccluded by postoperative angiography,two were associated with cerebral infarc­tion. Logistic regression analysis showedthat a new postoperative neurological defi­cit predicted an unforeseen vessel occlu­sion on postoperative angiography. Factorscould not be identified that predicted un­expected residual aneurysm or unclippedaneurysm. The inability to predict accu­rately the presence of residual or un­clipped aneurysm suggests that allpatients should undergo postoperativeangiography. Since a new postoperativeneurological deficit is one factor predictingunexpected arterial occlusion, intraopera­tive angiography may be necessary to helpreduce the incidence of stroke after aneu­rysm surgery. With study of more patientsor of factors not examined in this series, itmay be possible to select cases more accu­rately for intraoperative or postoperativeangiography.AUTHORS'ABSTRAcT