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adiofrequency Ablation: Evolution of a Treatmentoann Lohr, MD, FACS, RVT, and Aaron Kulwicki, MD

Superficial venous insufficiency of the lower extremities is a common affliction. There areseveral modalities available to the clinician to treat this problem. This article specificallyexamines the technique of radiofrequency ablation in the treatment of superficial venousinsufficiency. The evolution of the catheters used in radiofrequency ablation is discussedin detail. The mechanism of action of the radiofrequency energy on the vein wall isexplained. Several technical aspects of the technique, such as temperature set point andpull-back speed are described. The importance of tumescent anesthesia and its role inreducing complications are illustrated. Short- and long-term results of radiofrequencyablation are compared to results with both operative therapy or endovenous laser therapy,the results are similar if not better. Complications of radiofrequency ablation therapy arediscussed, emphasizing the advent of tumescent anesthesia and the resultant drop inparesthesias. Outcome analysis of radiofrequency ablation is shown to have positiveeffects on both clinical-etiologic-anatomic-pathophysiologic class and venous clinical se-verity score. Finally other considerations, including billing and necessary supplies, aresummarized. In summary, radiofrequency ablation is shown to be a safe and effectivemodality in the treatment of superficial venous insufficiency.Semin Vasc Surg 23:90-100 © 2010 Elsevier Inc. All rights reserved.

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HRONIC VENOUS INSUFFICIENCY of the lower ex-tremities is a common affliction. Various sources report

ates of chronic venous insufficiency (CVI) ranging from 1%o 40% in females and 1 to 17% in males. The reportedncidence of varicose veins ranges from 1% to 73% for fe-

ales and 2% to 56% in males. The prevalence of ulcerationn patients with CVI has been reported around 0.3%.1 For

any years, the only available treatment for varicose veinsas operative stripping and ligation. Approximately 10 years

go, endoluminal treatment of varicose veins with radiofre-uency ablation (RFA) became available to patients. Thisrticle will examine the history, mechanism, evolution, andesults of endoluminal RFA for varicose veins.

atheter Evolutionreatment of varicose veins by endoluminal RFA becameossible through development of special catheters designedo carry a radiofrequency (RF) signal (E. Jones, VNUS Med-cal Technologies Inc., personal communication, June 26,009). The first generation of RF catheters was available in aF size and employed prongs, which were expandable to a

ohn J. Cranley Vascular Lab, Good Samaritan Hospital, Cincinnati, OH.ddress reprint requests to Joann Lohr, Lohr Surgical Specialists, LLC, 6350

Glenway Avenue, Suite 203, Cincinnati, OH 45211. E-mail: jlohr@
tlohrss.com
0 0895-7967/10/$-see front matter © 2010 Elsevier Inc. All rights reserved.doi:10.1053/j.semvascsurg.2010.01.004

aximum of 8 mm. These first-generation RF catheters coulde used to treat veins 2 to 8 mm in diameter. The originalatheters accepted up to a 0.014-inch guide wire and came inwo lengths, 60 and 100 cm. For use, the catheter was con-ected to a RF generator via a resterilizable cable. A thermo-ouple on the catheter monitored the endoluminal wall tem-erature and relayed this information back to the generator,hich made power adjustments as necessary to avoid dam-

ge to the vein wall. The recommended treatment tempera-ure was 85°C (185°F). The original power generator dis-layed treatment time, temperature, impedance, and powerutput, which typically ranged from 2 to 4 watts, with aaximum output of 6 watts.The first case of varicose veins treated with the RF catheter

as reported from Bern, Switzerland in 1998 (E. Jones,NUS Medical Technologies Inc., personal communication,

une 26, 2009). In this case, general anesthesia was used.umescent local anesthesia was not used at this time. Theuthors employed high ligation in addition to RF ablation,nd used a continuous pull-back technique. Upon comple-ion of the procedure, they placed an Esmarch bandage fromoe to groin.

In December 1998, RFA closure was performed withoutoncomitant high ligation of the saphenous vein. A study byhandler and colleagues in 2000 examined results of high

igation versus no ligation in patients who underwent RFA
reatment of great saphenous vein (GSV) reflux.2 Inclusion
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Radiofrequency ablation 91

riteria were documented 1-second GSV reflux on Valsalva orompression-release. Patients were excluded if they demon-trated dominant deep system reflux or postthrombotichanges. There was one instance of thrombus propagationnto the common femoral vein (CFV) in a patient who did notndergo high ligation. Follow-up with duplex scanningound one or more patent tributaries in 6% of limbs (3/49)reated with high ligation and 35% of limbs (34/97) withoutigh ligation. Chandler et al found that patent tributariesere not specifically associated with recurrence of varicoseeins or reflux. Clinical-etiologic-anatomic-pathophysiologicCEAP) classification and symptom scores were significantlymproved in both groups (86% of high ligation limbs and8% of limbs without high ligation). The actuarial data pre-icted �90% freedom from reflux at 1 year in 94% of high

igation limbs and 87% of limbs without high ligation.Another study by Gradman examined reports of �21,000

ases of endovenous obliteration of the GSV with either laser,FA, or foam sclerotherapy.3 This study also found no sig-ificant differences in outcomes between patients who hadigh ligation versus those who did not.Between 1998 and 1999, an 8F catheter was introduced.

he electrodes in this catheter expanded to a diameter of 12m. However, the manufacturer recommended that treated

eins be in the range of 2 to 12 mm. Maximal vein diameterreated was 18 mm when combined with high ligation. Thisatheter added a continuous saline drip to the technique inrder to prevent thrombus formation in the electrodes andhermocouple.

In 1999, several notable advances were achieved. Inarch, the Closure catheter (VNUS Medical Technologies

nc., San Jose, CA) received US Food and Drug Administra-ion approval and later, the technique of tumescent anesthe-ia was introduced (E. Jones, VNUS Medical Technologiesnc., personal communication, June 26, 2009). The RFA pro-edure technique was further refined to now involve percu-aneous access to the GSV under ultrasound guidance. Anmpedance test in saline was performed to ensure properunctioning of the system. A saline drip was attached to theatheter with a drip rate of 2 mL/min. The catheter tip wasositioned 0.5 to 1 cm distal to the saphenofemoral junctionSFJ) or just distal to the superficial epigastric vein ostium ifhis was visualized. Subcutaneous tumescent anesthesia wasnfiltrated with or without ultrasound guidance to improvelectrode contact with the vein wall, protect against thermalnjury, exsanguinate, and compress the treated vein. The av-rage volume of tumescent anesthesia ranged from 150 to50 mL and varied widely per physician preference. An Es-arch bandage was applied from toe to groin. The patientas positioned in Trendelenburg position to further exsan-uinate the treated vein. External compression was applied tohe SFJ and a second impedance test was performed. Theull-back rate was 2 to 3 cm per second with initial retreat-ent at the SFJ prior to pull-back. External compression was

ontinuously applied during catheter withdrawal. Tempera-ure was set at 85°C (185°F). A 45-cm GSV was treated inpproximately 18 to 22 minutes. An intraoperative posttreat-
ent duplex scan was performed to evaluate treatment suc- o
ess. Retreatment of open segments was performed aseeded.In 2001, the catheter was modified to accommodate a

.025-inch guide wire. The 5F catheter was replaced with aF catheter. In 2002, ultrasound-guided perivenous tumes-ent infiltration within the saphenous compartment wasdded to the procedure technique, which allowed for even-ual discontinuation of the continuous saline drip throughhe catheter. This also decreased the rate of nerve injury (E.ones, VNUS Medical Technologies Inc., personal communi-ation, June 26, 2009).

In 2003, the ClosurePlus catheter (VNUS Medical Tech-ologies Inc., San Jose, CA) was introduced, replacing theriginal devices. This catheter was available in 6F and 8Fizes and came in 60- and 100-cm lengths. The catheterandle was smaller and lighter weight, with the connectionable integrated into the handle for a one-piece design. Ad-itionally, with US Food and Drug Administration approval,iameter limitations for treated veins were removed from theevice’s instructions for use (E. Jones, VNUS Medical Tech-ologies Inc., personal communication, June 26, 2009).It was also during this time that a treatment protocol using90°C (194°F) catheter was investigated. Although the

igher set point temperature allowed a faster pull-back timend was well-accepted by the physicians, clinical study re-ults were not consistent, so the 90°C protocol was notaunched. However, a further modification was made to the5°C (185°F) protocol in which it was recommended that the

nitial pull-back speed be 1 cm per minute for the first 5 cmf the treated vein. Thereafter, pull-back speed could be in-reased to 2 to 3 cm/min for the remaining length of thereated segment. Under this revised protocol, the treatmentime for a 45-cm vein was approximately 21 to 25 minutes (E.ones, VNUS Medical Technologies Inc., personal communi-ation, June 26, 2009).

In 2004, a second-generation radiofrequency generatoras launched, the RFG2. This RF generator replaced theumerical readouts for temperature with continuous moni-oring of impedance and temperature. This new configura-ion allowed for discontinuation of pretreatment impedanceesting. A radiofrequency stylet was introduced for the treat-ent of incompetent perforating veins. The radiofrequency

tylet received 510(k) clearance, making it the only endovas-ular device cleared for percutaneous treatment of refluxingerforating veins (E. Jones, VNUS Medical Technologies Inc.,ersonal communication, June 26, 2009).In 2006, the ClosureFAST (VNUS Medical Technologies

nc.) catheter was introduced. This new catheter allowed foregmental ablation as opposed to continuous pull-back. Thisatheter treats a 7-cm vein segment in one 20-second energyycle. The vein wall is heated conductively by a 7-cm coil athe distal end of the catheter. The treatment temperature is20°C (248°F) with an actual tissue temperature of 110°C230°F). The manufacturer recommends that the catheter tipe positioned 2 cm distal to the SFJ. A tumescent anesthesiaolume of approximately 10 mL per cm of treated vein is alsoecommended. The new procedure also entails two 20-sec-
nd treatment cycles in the segment closest to the SFJ using

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xternal compression with the ultrasound probe and twongertips distal to the probe applied over the coil during eachreatment cycle. This new catheter reduces treatment time topproximately 5 minutes. A continuous saline drip throughhe catheter is no longer needed. The first cases with the newatheter were performed in Europe in April 2006. In August006, the US Food and Drug Administration granted 501(k)pproval for the ClosureFAST catheter and it was launched inhe United States in 2007 (E. Jones, VNUS Medical Technol-gies Inc., personal communication, June 26, 2009). A sec-nd-generation radiofrequency stylet catheter was alsoaunched to treat incompetent perforator veins. This newtylet has an integrated sterile cable and a shortened devicehaft for easier vein access.

echanism of Actionhe mechanism of radiofrequency vein occlusion is illus-

rated in Figure 1. The RFA method of venous closurerimarily acts by inducing vein wall collagen contractionhrough heat-induced denaturation of the collagen matrix,ollowed by fibrotic sealing of the vessel lumen due tonjury and inflammation of the vein wall.4,5 Secondary

ethods involved in vein closure include endothelial de-udation and swelling of the vein wall components due toeat-induced inflammatory processes that occur as re-ponses to the temperature gradient created during thereatment from the intima to the adventitia. The total in-ury to the vein wall collagen and subsequently the totalhrinkage of the vein wall is determined by the intima todventitia temperature gradient and the duration of theime of heating.

An article by Schmedt et al in 2006 examined the histo-ogic effects of radiofrequency ablation on the vein wall in anx vivo bovine vein model.6 This study employed the VNUSlosure system for RFA. A 6F catheter was pulled back at aean velocity of 3 cm/s and set at a temperature of 85°C

185°F). Under macroscopic evaluation, veins treated withFA showed no evidence of thermal damage in the surround-

Figure 1 Mechanism of radiofrequency (RF) vein occlradiofrequency-mediated endovenous shrinkage and ocVeins and Telangiectasias—Diagnosis and Treatment
217-224, 1999, with permission.5
ng tissue layers. Although there was no vessel occlusion inhe veins treated with RFA, the veins did demonstrate indu-ation and thickening of the vein wall and contraction of theein lumen, and the endothelium of the RFA veins demon-trated a whitish discoloration. There was no evidence ofransmural lesions in the RFA veins. Under microscopic anal-sis, RFA-treated veins demonstrated circular disintegrationf the intima cell layer. The RFA-treated veins also showedomogeneous cylindrically affected medial lesions with in-ercellular splits and gaps. No evidence of transmural thermalesions or vessel perforations was seen in the RFA-treatedeins. The authors theorized the circular expansion of theFA probes as well as the computer controlled regulation of

he RF generator were factors that promoted circular homo-eneous distribution of thermal energy, which may result inlack of wall perforation.

et Point Temperaturend Pull-Back Speed

ecommendations for set point temperature and pull-backpeed are based on the equation that “energy equals temper-ture multiplied by contact time.” The manufacturer recom-endations for temperature have been a set point of 85°C

185°F) for its first two generations of RFA catheters (E.ones, VNUS Medical Technologies Inc., personal communi-ation, June 26, 2009). These recommendations also in-luded a pull-back speed of 2 to 3 cm/s. Although the firstwo generations of catheters were in use, various adjusted setoint temperatures, as well as variable pull-back rates weresed for treatment.In 2004, Zikorus and Mirizzi examined the effects of in-

reasing set point temperature and pull-back speed on RFAn a bovine vein model.4 The authors used a set point tem-erature of 90°C (194°F) and a pullback speed of 6 cm/min.ith the use of a 2-mm saline tumescent anesthesia layer, the

Reprinted from Weiss RB, Goldman MP: Controlled, in Goldman MP, Weiss RA, Bergan JJ (eds): Varicose

. St Louis, MO, Quality Medical Publishing Inc., pp

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uthors found comparable temperature at the adventitial sur-ace between the veins treated with a set point of 85°C and aullback of 3 cm/min versus veins treated with a set point of0°C and a pullback of 6 cm/min.4

A report by Dunn and coworkers in 2006 reported on 85imbs treated with RFA at a higher set point and pull-backpeed.7 The authors used a set point temperature of 90°C194°F) with a pull-back speed of 2 to 3 cm/min in theroximal 5 cm of vein and 5 to 6 cm/min in the rest of thereated vein. The study found an overall success rate of 88%,hich was comparable to a set point of 85°C and a pull-back

ate of 2 to 3 cm/min. By increasing the set point and pull-ack speed, the authors found that mean treatment timesecreased from approximately 18 to 8 minutes. Again, it is

mportant to note that the manufacturer still recommended aet point temperature of 85°C (185°F) and a pullback speedf 2 to 3 cm/min. These issues are no longer relevant with theatest generation of ClosureFAST catheters.7

umescent Anesthesiaumescent anesthesia allows the vein to be displaced further

rom the underlying skin. A tumescent solution consists ofactated Ringer’s or saline combined with lidocaine, epi-ephrine, and bicarbonate (see Tables 1 and 2). Using ultra-ound guidance, this solution is instilled percutaneously be-ow the saphenous fascia and above the deep muscular fasciao surround the vein.8,9

This solution provides a fluid bath “heat sink” to displaceeat radiating up to 1.5 mm beyond the vein wall. This re-ults in decreased skin burn and sensory nerve injury rates. Ary “saphenous vein” with inflow tributaries eliminated byompression is also created.

In 2004, Zikorus and Mirizzi demonstrated significant de-reases in peak adventitial mean temperatures with the addi-ion of a tumescent anesthesia layer.4 At a set point temper-ture of 85°C and a pull-back speed of 3 cm/min, theyemonstrated that the peak adventitial mean temperatureas reduced from 64.4°C (147.9°F) to 51.3°C (124.3°F). Atset point temperature of 90°C (194°F) and a pull-back

peed of 6 cm/min, they demonstrated a decrease in the peakdventitial mean temperature from 64.9°C (148.8°F) to7.7°C (117.9°F).In 2005, Merchant and colleagues demonstrated a signifi-

ant reduction in the incidence of paresthesia after the au-hors introduced tumescent anesthesia to the RFA proce-ure.10 Rates of paresthesia dropped from 14.5% (70/484) to

able 1 Tumescent Solution

ormal Saline Solution 1000 mLidocaine 1% 500-1000 mgpinephrine 1 mgodium Bicarbonate 12.5 mEq

umescent anesthesia formulation used at TriHealth Inc. hospitals inCincinnati, OH (Good Samaritan and Bethesda North) (B. Steele,Bethesda North Hospital Pharmacy, personal communication,

sApril 29, 2010).

.1% (34/374) after implementation of tumescent anesthesia.he overall incidence of paresthesia decreased to 6.7% and% at 6 months and 4 years with the use of tumescent anes-hesia.

Data from the clinical registry showed that the rates of skinurn before tumescent anesthesia was 1.8% (10/542 pa-ients).10 After the use of tumescent infiltration it was 0.5%2/394). These complication rates may also be decreased byimiting treatment of the GSV to the thigh segment.

esults of Radiofrequencyblation on GSV Refluxnd CEAP Classification

n 2006, Marston and colleagues looked at the effects ofndovenous saphenous ablation on patients with CEAPcores of 3 to 6 without deep venous insufficiency.11 Fifty-ight limbs were treated with RFA and 31 limbs were treatedith endovenous laser (EVLT). All GSVs treated with RFAere �12 mm in diameter. Tumescent anesthesia and ansmarch bandage were used. The temperature set point wasetween 85°C and 90°C (185°F and 194°F), with a pull-backpeed of 1 cm/min for the initial 5 cm and 2 cm/min for theemaining vein segment treated.

There were no significant differences in the frequency ofomplete closure, partial closure, or failure to close betweenhe RFA- and EVLT-treated veins. There was a significantmprovement in venous filling index (VFI) in all patients witho significant difference between those treated with RFA andVLT. An improved VFI was found in 95% of limbs afterblation, with normal VFI (�2 mL/s) found in 78% of theimbs and a mildly abnormal VFI (2 to 4 mL/s) found in 17%f the limbs. Specifically, the average preoperative VFI inFA-treated veins was 5.1 mL/s and the average postopera-

ive VFI in EVLT-treated limbs was 2.1 mL/s. Veins withartial or unsuccessful ablation were more likely to exhibit anbnormal postoperative VFI. Overall, the venous clinical se-erity score (VCSS) for both groups (RFA and EVLT) im-roved from an average of 11.5 to 4.1.In 2007, Vasquez et al examined the results of RFA on

enous clinical severity score and CEAP classification in 682imbs treated with RFA.12 RFA was offered to those patientsith persistent symptomatic venous disease and a CEAP clas-

able 2 Preparation of Solution for Tumescent Anesthesia

mL

inger’s lactate solution 450 mLidocaine 1% with epinephrine 1:100,000 50 mLodium bicarbonate 8.4% 16 mLroduces a solution of lidocaine 0.1% withepinephrine 1:1,000,000

516 mL

dapted from Merchant RF, Kistner RL: Radiofrequency treatment ofthe incompetent saphenous vein, in Gloviczki P (ed): Handbookof Venous Disorders: Guidelines of the American Venous Forum(3rd ed). London, England, UK, Hodder Arnold, 2009, p 410.9

ification of 2 to 6. Patients were excluded if they presented

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ith deep venous thrombosis (DVT), venous outflow ob-truction, arterial insufficiency, or an ankle brachial index0.8, planned future pregnancy, noncompliance with initial

onservative measures, or obesity. Patients were not ex-luded if they presented with a postthrombotic syndrome oroncomitant deep vein or perforator vein reflux. Tumescentnesthesia was used in all patients.

Eighty percent of treated limbs had a pretreatment CEAPlassification of 3 or 4. RFA significantly reduced symptoms ofain (95.7% to 15.2%), the percentage of limbs with multiple orxtensive varicosities (80.8% to 6.6%), venous edema (92.4% to7%), skin pigmentation (15.3% to 5.4%), cellulitis (10.2%o 1.9%), and induration (17.1% to 7%). RFA was also found tomprove ulcer healing. The overall rate of ulcer healing was6%. Overall mean baseline venous clinical severity scores were.8 at baseline and 3.6 at last follow-up visit.12

omparison totripping and Ligation

or many years, the only treatment for varicose veins con-isted of various forms of surgical therapy. The most fre-uently used method was stripping and ligation of the vari-ose vein. Several studies have compared results of RFAlosure to operative stripping and ligation. A prospective ran-omized trial (EVOLVeS [Endovenous Radiofrequencybliteration (Closure Procedure) Versus Ligation And Strip-ing]) by Lurie et al in 2003 randomized patients to eitherperative stripping and high ligation or RFA closure with theNUS device.13 Inclusion criteria were reverse flow in theSVs �0.5 seconds, age between 21 and 80 years, CEAPlasses 2 to 4, ambulatory status, saphenous vein diameter12 mm, and availability for follow-up. Exclusion criteria

ncluded vein diameter �12 mm or �2 mm, duplication ofhe saphenous trunk, incompetent accessory saphenous veinributaries, thigh varicosities, previous DVT, an ankle bra-hial index �0.9, axial deep vein reflux, and GSV tortuosity.fter randomization, RFA was performed in 45 limbs andtripping and ligation was performed in 36 limbs.

The authors examined procedure-related complications,atient recovery, and quality-of-life outcomes scores. Imme-iate complications included one intraoperative hematoma

n each treatment arm, one perforation in the RFA group, andwo vein tears in the stripping and ligation group. At 3-weekollow-up, the RFA group was found to have significantlyewer overall complications, including less ecchymosis andewer hematomas. The authors did find that the RFA patientsemonstrated a slight trend toward higher incidence of par-sthesia. Notably, the authors were not using tumescent an-sthesia during this study period. Immediate success was5% in the RFA group and 100% in the stripping and ligationroup. The authors found a statistically significant differencen both time until resumption of normal activity and timentil return to normal activity in the two groups. On average,he time to return to normal activity in the RFA group was.15 days compared to 3.89 days in the stripping and ligation
roup. Mean values for return to work averaged 4.7 days in t
he RFA group compared to 12.4 days in the stripping andigation group. At 3 weeks, the authors found that the RFAroup demonstrated statistically significant differences withegard to decreased pain and better global and physicalcores in quality-of-life measurements.13

The Lurie group also examined the 2-year follow-up of theVOLVeS patients.14 At 2 years, there was a difference, al-

hough not statistically significant, in recurrent varicoseeins, with 14% of RFA patients demonstrating recurrenceersus 21% in the stripping and ligation group. Global qual-ty-of-life scores, as well as pain scores, remained statisticallyignificant in favor of RFA at 2 years.14

A 2005 study by Perälä et al reported a study of 28 patientsandomized to RFA versus stripping and ligation.15 The studyncluded 15 patients in the RFA group and 13 patients in thetripping and ligation group. All patients underwent a 3-yearollow-up with duplex ultrasonography and clinical evalua-ion with calculation of a Venous Clinical Severity ScoreVCSS), Venous Segmental Disease Score, and Venous Dis-bility Score. There were no statistically significant differ-nces between groups in terms of improvement in VCSS,enous Segmental Disease Score, or Venous Disability Score.t 3 years, there were no statistically significant differencesetween the two groups in terms of recurrence of varicoseeins, although there was a trend for higher recurrence in theroup treated with endovenous therapy. The authors postu-ated that patients with a VFI �2 mL/s, reflux at two or moreites, and deep venous incompetence may have a poorer out-omes with RFA therapy.

In 2008, Luebke et al performed a meta-analysis of RFA ver-us stripping and ligation.16 This review examined eight studiesnd included both previously mentioned studies by Lurie etl.13,14 In contrast to the Lurie group, the meta-analysis demon-trated no significant difference in complications between RFAnd stripping and ligation at 4 weeks. However, after 1 week,FA showed lower rates of tenderness and ecchymosis. RFA alsoesulted in fewer hematomas at 72 hours, 1 week, and 3 weeks.here was no significant difference between groups in terms of

mmediate GSV occlusion, complete GSV occlusion, incompe-ent GSV closure, freedom from reflux, recurrent varicose veins,ecanalization at 2 years, and neovascularization. The recur-ence rate of varicose veins was lower, although not statisticallyignificant, in the RFA group. Overall, RFA afforded higheruality of life and lower pain scores for patients. Most notably,atients returned to normal activity and returned to work fasterollowing the RFA procedure. The authors concluded that al-hough RFA demonstrates definite advantages in the short-termith regard to patient pain and quality of life, long-term (5 to 10ears) follow-up data are needed to evaluate whether RFA isquivalent or superior to stripping and ligation in terms of abo-ition of reflux.

omparison tondovenous Laser Therapy

n 2005, Puggioni and colleagues compared RFA to EVLT in
erms of efficacy and complication rates.17 Their study sam-

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le included 53 limbs treated with RFA and 77 limbs treatedith EVLT. Immediate success rates were not statistically

ignificant between groups (96% for RFA v 100% for EVLT).he authors found a statistically significant difference in theumber of veins requiring a second intervention, with 17%f the RFA treated veins requiring retreatment versus 0% ofhe EVLT-treated veins. Only the EVLT group demonstratedrotrusion of thrombus into the CFV (2.3%). There was aonstatistically significant trend toward lower complicationates with RFA (7.6%) versus EVLT (20.8%). Puggioni et aloncluded that EVLT had somewhat higher immediate oc-lusion rates, but also higher complication rates than RFA.hey also suggested that DVT prophylaxis might be consid-red in patients older than 50 years of age.

In 2006, Almeida and Raines compared 819 endovenousaser ablation (EVLA)�treated limbs to 128 RFA-treatedimbs.18 Both treatment groups received tumescent anesthe-ia. Primary closure rates were 92% for the EVLA-treatedeins and 85% for the RFA-treated veins. This suggested atatistically significant advantage for EVLA in terms of imme-iate closure. Complication rates were similar between thewo groups, with two instances of paresthesia in each group.owever, thrombus extension into the CFV requiring anti-

oagulation occurred in two patients treated with EVLA ando patients treated with RFA.Almeida and colleagues evaluated RF thermal ablation us-

ng the ClosureFAST system to investigate whether it offeredetter outcomes for recovery and improved quality of lifeQOL) versus 980-nm endovenous laser thermal ablation ofhe GSV.19 This prospective, single-blind study was con-ucted at five American sites and one European site andtudied 87 veins in 69 patients who were randomized tolosureFAST or EVLA. Primary outcomes measures includedostoperative pain, ecchymosis, tenderness, and adverserocedure sequelae. Secondary outcomes included VCSS and

able 3 Short-Term Success Rates of Endovenous Therapies

First Author, Year Therapy n S

erchant,20 2002 RFA 319ingorani,21 2004 RFA 73hortell,22 2005 RFA 335in,23 2003 EVLT 499abrera,24 2000 Foam 500

bbreviations: CFV, common femoral vein; EVLT, endovenous lasvenous thromboembolism.

eprinted from Stirling M, Shortell CK: Endovascular treatment of v

able 4 Intermediate and Long-Term Success Rates of Endov

First Author, Year Therapy nF

urie et al,14 2005 RFA 65erchant et al,10 2005 RFA 1,078in et al,23 2003 EVLT 499abrera et al,24 2000 Foam 500

bbreviations: EVLT, endovenous laser treatment; NR, data not rep
rom Stirling M, Shortell CK. Endovascular treatment of varicose veins. S
OL scores. All outcomes were measured at 48 hours, 1eek, 2 weeks, and 1 month after treatment. Pain, ecchymo-

is, and tenderness were all statistically lower in the Closure-AST group at 48 hours, 1 week, and 2 weeks. Minor com-lications were more prevalent in the EVLA group (P � .21).o major complications were reported. VCSS and QOL mea-

ures were statistically more favorable in the ClosureFASTroup at 48 hours, 1 week, and 2 weeks. It was concludedhat RF thermal ablation was significantly superior to EVLAith respect to the recovery and QOL outcomes measured in

his multicenter prospective trial. Short-term results fromther studies are summarized in Table 3, while intermediatend long-term results are presented in Table 4.

Overall short-term occlusion rates are similar between EVLAnd RFA. RFA does appear to confer some advantages in termsf complications. Although there is not much literature usinghe latest ClosureFAST catheter, it does seem that the smalldvantages over EVLA will become even more significant.

omplicationshrombus extension into the CFV can lead to DVT if notecognized and may be treated with either low moleculareight heparin or operative thrombectomy. Duplex ultra-

ound is a crucial component of the protocol and should beerformed within 72 hours of the initial procedure.26 Figureshows an ideal duplex image after RFA of the CFV.At the 2007 American Venous Forum, Kabnick et al pre-

ented data advocating the concept of endovenous heat-in-uced thrombosis.26 It was suggested that treatment could betratified based on the amount of thrombus extension fromhe SFJ into the CFV. Anticoagulation was recommended for

50% CFV involvement.The great saphenous nerve is adherent to the GSV in the

istal limb. Injury to the nerve in this area is increased with

ss (%) VTE (%) CFV Clot Extension (%)

1.5 01.4 150.7 20 NR0 NR

tment; NR, data not reported; RFA, radiofrequency ablation; VTE,

e veins. Semin Vasc Surg 19:109-115, 2006.25

Therapies

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Recurrent VaricoseVeins (%)

4 1412 21

7 NR5 14

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oth RFA and surgical intervention. Limiting treatment to thebove-knee segment can significantly decrease nerve injuryates. Skin burns were initially seen with early RFA treat-ent, but have become almost nonexistent with the addition

f tumescent anesthesia. Phlebitis and hyperpigmentationay occur as a result of residual blood trapped within the

eins.27

These conditions usually resolve over several weeks with-ut any specific treatment. Anatomic failures may be catego-ized into three groups, as illustrated in Figure 3.27

Type I is described as failure of closure. Nonocclusionccurred in 12.4% according to a 2005 report by Merchantnd Pichot from the Closure Study Group.27 Recanalizationesulted when initially occluded veins recanalized either par-ially or completely (type II failures). This was the most com-on anatomical failure; 2.4% of the time, this was associatedith a refluxing tributary or an incompetent perforating vein.

Figure 2 Ideal duplex image after radiofrequency ablationfemoral vein (CFV). A, artery; CSIV, confluence of the sucompression.

Figure 3 Types of anatomical failure are illustrated in thefailure to completely occlude, with or without reflux preIII, the treated GSV is occluded, but reflux is present invcommon femoral vein. Reprinted from Merchant RF, Piendovenous radiofrequency obliteration of saphenous re
Surg 42:502-509, 2005 with permission.27
ype III (groin reflux) failure refers to a situation in which theein trunk is occluded, but reflux is detected in the groin,ften involving an accessory vein. This failure type makes up7.8% of anatomical failures.27

Technical challenges include difficult access, difficulty ad-ancing the catheter, treatment interruption, inability to in-ert the catheter, tortuous or GSV of uneven sizes.28 Patientsay complain of painful incision sites or symptoms of heat,

nd may have saphenous nerve pain. Dysrhythmias and va-ovagal reactions may also occur.

FA and Long-Term Follow-Upn 2005, Ogawa and colleagues followed up 25 legs that hadndergone RFA with the 6F RF VNUS Closure system (VNUSedical Technologies) at 1 day and 1 month with duplex

ltrasound.29 All procedures were performed with a 6F cath-

occluded without thrombus extension into the commonial inguinal veins; TA, total occluding acute; W/C, with

s (left to right). (A) Type I, great saphenous vein (GSV)B) and (C) Type II, partially recanalized GSV. (D) Typebranches near the saphenofemoral junction (SFJ). CFV,for the Closure Study Group: Long-term outcomes ofa treatment for superficial venous insufficiency. J Vasc

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ter and tumescent anesthesia. At both 1-day and 1-monthollow-up, 1 treated vein demonstrated complete obstruc-ion, 23 treated veins demonstrated complete obstructionith persistent flow in the superior epigastric vein, and 1 veinemonstrated near-complete obstruction with persistentow in a vein segment �5 cm. No treated veins showedersistent flow �5 cm from the SFJ.Manfrini et al followed patients for 6 months to 1 year after

he RFA procedure.30 At 6-month follow-up, persistent oc-lusion was observed in 91% (50/55) of treated veins. Recur-ent reflux was demonstrated in only two of the five recana-ized segments. Twenty treated veins were available for-year follow-up and all of these veins demonstrated occlu-ion.

In 2002, Weiss and Weiss reported follow-up of patientseevaluated at 1 week, 6 weeks, 6 month, 1 year, and 2 yearsost-RFA treatment.31 At 1-week follow-up, 98% (137/140)f treated veins showed vein occlusion. In the three patientsith incomplete occlusion, flow was only demonstrated in

mall segments and was not accompanied by saphenous veineflux. At 6 weeks follow-up, 4% (5/98) of treated veins dem-nstrated incomplete obliteration. Three of the five veinsith recurrent flow demonstrated complete recanalization atmonths. The other two were treated with sclerotherapy andemonstrated complete occlusion at 6 months. At 1-yearollow-up, there was no new incidence of recanalization. At-year follow-up, 19 of 21 treated veins had completely dis-ppeared, resulting in a clinical success rate of 90%.

Nicolini and colleagues followed patients for three yearsfter RFA treatment.32 At 1 year, 88.5% (223/252) of treatedeins had absence of reflux. At 2 years, 87.8% (130/148) of

Figure 4 (A) Pretreatment duplex image showing mid(B) Same vein level at 6 months, showing diameter reduclumen without flow. (C) Same level at 2 years, now seeshrinkage and no discernable lumen. Reprinted from Pifindings two years after great saphenous vein radiofrequ
with permission.28
reated veins showed no reflux. At 3 years, 88% (60/68) ofreated veins were free from reflux. In the subgroup of veinshat were followed for 3 years, percentages of veins withouteflux were 94%, 90%, and 88% at 1, 2, and 3 years, respec-ively.

In 2005, Merchant and colleagues examined up to 4-yearesults after RFA.10 Occlusion rates were 97.4% (836/858) atweek, 91% (406/446) at 6 months, 88.8% (341/384) at 1

ear, 86.2% (181/210) at 2 years, 84.2% (96/114) at 3 years,nd 88.8% (87/98) at 4 years. The percentage of veins thatere reflux-free at 6 months, 1, 2, 3, and 4 years were 91%,9.3%, 86.2%, 86%, and 85.7%, respectively. A second re-ort by the Merchant group in 2005 found occlusion rates of6.8%, 89.2%, 87.1%, 88.2%, 83.5%, 84.9%, and 87.2% atweek, 1, 2, 3, 4, and 5 years respectively.27 Similarly, the

ercentages of treated veins that did not demonstrate refluxt 1 week, 1, 2, 3, 4, and 5 years were 96.6%, 91.3%, 88.2%,8.2%, 88%, 86.6%, and 83.8%, respectively.In conclusion, available reports indicate that occlusion

ates and reflux-free rates are �85% with 4-year follow-up.

ollow-Upltrasound Examination

here have been several reports describing ultrasound find-ngs after RFA of the GSV. Figure 4 demonstrates GSV duplexndings of RFA-treated veins at 6 months and 2 years post-reatment.7 In a report by Pichot et al in 2004, the authorserformed ultrasound examinations in 63 groins of patientsho had undergone RFA without concomitant SFJ ligation.28

great saphenous vein reflux; note diameter markers.ein wall thickening, and a narrow, irregular echolucenteatureless hyperechogenic stripe with further diameter, Kabnick LS, Creton D, et al: Duplex ultrasound scanndovenous obliteration. J Vasc Surg 39:189-195, 2004

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he most common pattern on ultrasound was a patent SFJeceiving prograde flow from proximal GSV tributarieshrough a short (�2 cm) segment above an obliterated GSVFig 5).

This pattern was found in 81.7% of treated limbs. Theuthors found long-segment patency (21 and 27 cm) in twoimbs. SFJ reflux was present in five limbs and showed noirect relationship to GSV patency length. Ultrasound found04 open tributaries with reflux demonstrated in only eightf the tributaries (7.7%). There was no evidence of neovas-ularity in any groin as every visible vein could be classified asmajor truncal vein. The authors concluded that the RFArocedure was less likely than stripping and ligation to in-uce neovascularity in the groin. Furthermore, the authorsostulated that the principal cause of recurrent thigh refluxnd subsequent varicosities after the RFA procedure is linkedo the potential for reflux in the anterolateral and posterome-ial thigh tributaries arising from the GSV.In 2004, Salles-Cunha et al reported significantly different

ndings than the previously mentioned authors.33 In thistudy, 106 extremities in 89 patients were followed withltrasound examinations at a median of 9 months post-RFA.n contrast to Pichot et al,28 flush ligation and division of theSV and ligation and division of the SFJ tributaries wereerformed in 88% of the RFA-treated extremities. The au-hors increased the color-flow sensitivity for the post-RFAltrasound scans to improve detection of recanalized GSVegments, as well as small vessel networks. They definedmall vessel networks as veins and arteries �2 mm in diam-ter. The authors found that 65% of extremities had smallessel networks detected in the SFJ, thigh, or both. GSVecanalization was identified in 18% of extremities. Accord-ng to Salles-Cuhna et al, SFJ ligation did not affect smallessel networks in the thigh or the prevalence of GSV recan-

igure 5 Duplex ultrasound findings 2 years after radiofrequencyblation. Reprinted from Pichot O, Kabnick LS, Creton D, et al:uplex ultrasound scan findings two years after great saphenousein radiofrequency endovenous obliteration. J Vasc Surg 39:189-95, 2004 with permission.28

lization. d

Findings of the post-RFA�treated veins on ultrasound re-ain controversial. Whether or not small vessel networks oreovascularization can be demonstrated may depend on theensitivity of the ultrasound equipment. Further standard-zed reports are needed to clear up this issue.

he Future—ThelosureFAST Catheter

he details of ClosureFAST catheter have been outlined inhis article. Briefly, the ClosureFAST RFA catheter treats a-cm segment of vein using one 20-second energy cycle (E.ones, VNUS Medical Technologies Inc., personal communi-ation, June 26, 2009). The temperature set point is 120°C248°F) and there is no pull-back speed. The catheter tip islaced 2 cm distal to the SFJ and the manufacturer recom-ends treating the initial segment with two 20-second treat-ent cycles.An article by Proebstle and coworkers in 2008 reports on

he first clinical experience for the ClosureFAST RFA cathetern 252 limbs.34 Inclusion criteria were reflux �0.5 secondsontinuously from the SFJ to the distal point of reflux, age 18o 80 years, physical condition allowing for ambulation afterhe procedure, and availability for posttreatment follow-up.xclusion criteria included pregnancy, breastfeeding, and ev-

dence of thrombus in the vein segment to be treated. Largeein diameters were not among the exclusion criteria. Theverage age of the patient was 50.5 years and mean GSViameter was 5.7 mm. All patients received tumescent anes-hesia. A 7F diameter catheter was used with a temperature of20°C (248°F), and 20-second treatment cycles. Additionalreatments included phlebectomy in 71% and foam sclero-herapy in 13.9% of patients. Average procedure time fromatheter insertion to catheter removal was 16.4 minutes.

Immediate occlusion was reported to be 100%. Accordingo Kaplan-Meier analysis, vein occlusion and reflux-free ratesere 99.6% at 3 days, 3 months, and 6 months. The patent

tump length at the SFJ averaged 1.5 cm at 6 months. Inimbs that had 6-month follow-up, treated veins decreased iniameter size by 19.9% at 3 days, 26.6% at 3 months, and3.5% at 6 months.34

Limb pain, reported in 57.5% of patients at preprocedure,as reduced to 10.8% at 3 days postprocedure. The percentf limbs with edema decreased from 52.8% to 3.2%. Theverage VCSS of 3.9 decreased to 3.4 at 3 days, 1.6 at 3onths, and 1.6 at 6 months. Return to normal activity oc-

urred on the same day in more than half of the patients, withn average return to normal activity at 1 day. DVT or thermalkin injury was not observed in any of the patients. Paresthe-ias occurred as localized patches in 3.2% of treated limbs.hrombophlebitis was demonstrated in 0.8% of treated

imbs. Ecchymosis was noted in 16 limbs and hematoma athe puncture site was found in four limbs. Skin pigmentation
eveloped in five limbs.34

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illing Codes anddditional Supplies

urrent Procedural Terminology codes include 36475 en-ovenous ablation of the first vein and 36476 for subsequenteins; 36470 may be added if sclerotherapy is performeddjunctly. Duplex scan of the complete extremity, 93970,ay also be used for the follow-up scan performed 3 to 5 daysosttreatment. Alternately, if the duplex scan is a unilateral

imited study, the code is 93971. Current Procedural Termi-ology codes for diagnosis procedures range from 454.0 to54.8, varicose veins with symptoms or complications. Ve-ous insufficiency may be coded as 459.81. Modifiers shoulde applied as needed. Sedation codes may also be providedhen appropriate, and facility codes may also be applicable

o hospital or ambulatory surgery center services.35

Other supplies that may be coded include pressure gradi-nt stockings. Regardless of how many veins are treated in theddition to the initial vein, the add-on code is only reportablence for each extremity treated. Reimbursement for officerocedures is substantially higher than for those done in aospital setting.35

onclusionn conclusion, experience during the past 10 years shows thatndovenous ablation is safe, and the evolution of new tech-ologies has improved both safety and efficacy of this ther-py. Technical challenges, intraoperative and postoperativeisks, and adverse sequelae are rare, and are generally lessrequent than with more traditional surgical therapy. Strip-ing and ligation is the only treatment for varicose veins forhich long-term follow-up data are available. Endovenous

herapy, traditional, and surgical intervention require long-erm prospective comparisons.

The concept that minimally invasive treatment options,

able 5 American Venous Forum Guidelines for Treating the

No. Guideline

.9.1 Incompetence of the great saphenous vein can betreated safely and effectively usingradiofrequency ablation

.9.2 Radiofrequency ablation of the great saphenousyields comparable clinical outcomes versustraditional stripping and ligation up to 5 years

.9.3 Due to delayed convalescence, increasedcomplications, and higher morbidity,radiofrequency ablation of the great saphenousvein is suggested for high-risk patients includingthose who are obese, on anticoagulation, orhaving significant medical problems

dapted from Merchant RF, Kistner RL: Radiofrequency treatment ofDisorders: Guidelines of the American Venous Forum (3rd ed). L

ncluding perforating vein incompetence, are uniformly bet-

er than traditional approaches needs long-term validation.ew catheter designs will afford a wider application of treat-ent options for perforating vein incompetence. Results ofifferent catheter designs and treatment protocols will needo be validated.

Randomized trials of radiofrequency ablation and veintripping have suggested improved recuperative time, fastereturn to work, less postoperative pain and limitation ofhysical activity, and better QOL than vein stripping. Short-erm trials showed fewer complications and adverse effectsor radiofrequency-treated patients than for patients withein stripping. Two-year follow-up showed QOL scores wereignificantly better than after vein stripping. Adverse effectsncluded numbness and paresthesias, vessel perforation, in-ection, blood clots, and thromboembolism. RFA of the veinas definite advantages over stripping and ligation in QOL,eturn to work, and pain control. Endovascular GSV treat-ent has an overall relatively lower complication rate, es-ecially in the tumescent anesthesia era. RFA is safe andell-accepted by patients. The American Venous Forum rec-mmends RFA as a safe and effective treatment for incompe-ence of the GSV and notes that clinical outcomes are com-arable to those for conventional stripping and ligation up toyears posttreatment (see Table 5).11 The AVF further sug-

ests that RFA be the treatment of choice for high-risk pa-ients, such as those who are obese, are on anticoagulantherapy, or have problematic medical conditions.

eferences1. Robertson L, Evans C, Fowkes FG: Epidemiology of chronic venous

disease. Phlebology 23:103-111, 20082. Chandler JG, Pichot O, Sessa C, et al: Defining the role of extended

saphenofemoral junction ligation: A prospective comparative study. JVasc Surg 32:941-953, 2000

3. Gradman WS: Adjunctive proximal vein ligation with endovenousobliteration of great saphenous vein reflux: Does it have clinical value?Ann Vasc Surg 21:155-158, 2007

petent Saphenous Vein Using Radiofrequency Ablation

Level ofRecommendation

1, recommended; 2,suggested)

Quality of Evidence(A, high; B, moderate; C,

low or very low)

1 A

— C

2 C

ompetent saphenous vein, in Gloviczki P (ed): Handbook of Venous, UK, Hodder Arnold, 2009, p 415.9

Incom

(

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4. Zikorus AW, Mirizzi MS: Evaluation of setpoint temperature and pull-

1

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2

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3


back speed on vein adventitial temperature during endovenousradiofrequency energy delivery in an in-vitro model. Vasc EndovascSurg 38:167-174, 2004

5. Weiss RB, Goldman MP: Controlled radiofrequency-mediated en-dovenous shrinkage and occlusion, in Goldman MP, Weiss RA, BerganJJ (eds): Varicose Veins and Telangiectasias—Diagnosis and Treatment(2nd ed). St Louis, MO, Quality Medical Publishing Inc., 1999, pp217-224

6. Schmedt C-G, Sroka R, Steckmeier S, et al: Investigation of radiofre-quency and laser (980 nm) effects after endoluminal treatment of sa-phenous vein insufficiency in an ex-vivo model. Eur J Vasc EndovascSurg 32:318-325, 2006

7. Dunn CW, Kabnick LS, Merchant RF, et al: Endovascular radiofre-quency obliteration using 90°C for treatment of great saphenous vein.Ann Vas Surg 20:625-629, 2006

8. Smith SR, Goldman MP: Tumescent anesthesia in ambulatory phlebec-tomy. Dermatol Surg 24:453-456, 1998

9. Merchant RF, Kistner RL: Radiofrequency treatment of the incompetentsaphenous vein, in Gloviczki P (ed). Handbook of Venous Disorders:Guidelines of the American Venous Forum (ed 3). London, England,UK, Hodder Arnold, 2009, pp 409-417

0. Merchant RF, Pichot O, Myers KA: Four-year follow-up on endovascu-lar radiofrequency obliteration of great saphenous reflux. DermatolSurg 31:129-134, 2005

1. Marston WA, Owens LV, Davies S, et al: Endovenous saphenous abla-tion corrects the hemodynamic abnormality in patients with CEAPclinical class 3-6 CVI due to superficial reflux. Vasc Endovasc Surg40:125-130, 2006

2. Vasquez MA, Wang J, Mahathanaruk M, et al: The utility of the venousclinical severity score in 682 limbs treated by radiofrequency saphe-nous vein ablation. J Vasc Surg 45:1008-1015, 2007

3. Lurie F, Creton D, Eklof B, et al: Prospective randomized study ofendovenous radiofrequency obliteration (closure procedure) versus li-gation and stripping in a selected patient population (EVOLVeS study).J Vasc Surg 38:207-214, 2003

4. Lurie F, Creton D, Eklof B, et al: Prospective randomised study ofendovenous radiofrequency obliteration (closure) versus ligation andvein stripping (EVOLVeS): Two-year follow-up. Eur J Vasc EndovascSurg 29:67-73, 2005

5. Perälä J, Rauto T, Biancari F, et al: Radiofrequency endovenous oblit-eration versus stripping of the long saphenous vein in the managementof primary varicose veins: 3-year outcome of a randomized study. AnnVasc Surg 19:669-672, 2005

6. Luebke T, Gawenda M, Heckenkamp J, et al: Meta-analysis of en-dovenous radiofrequency obliteration of the great saphenous vein inprimary varicosis. J Endovasc Ther 15:213-223, 2008

7. Puggioni A, Kalra M, Carmo M, et al: Endovenous laser therapy andradiofrequency ablation of the great saphenous vein: Analysis of earlyefficacy and complications. J Vasc Surg 42:488-493, 2005

8. Almeida JI, Raines JK: Radiofrequency ablation and laser ablation in thetreatment of varicose veins. Ann Vas Surg 20:547-552, 2006

9. Almeida JI, Kaufman J, Göckeritz O, et al: Radiofrequency endovenous
ClosureFAST versus laser ablation for the treatment of great saphenous
reflux: A multicenter, single-blinded, randomized study (RECOVERYstudy). J Vasc Interv Radiol 20:752-759, 2009

0. Merchant RF, DePalma RG, Kabnick LS: Endovascular obliteration ofsaphenous reflux: A multicenter study. J Vasc Surg 35:1190-1196,2002

1. Hingorani AP, Ascher E, Markevich N, et al: Deep venous thrombosisafter radiofrequency ablation of greater saphenous vein: A word ofcaution. J Vasc Surg 40:500-504, 2004

2. Shortell C, Rhodes JR, Johanssen M: Radiofrequency ablation for su-perficial venous reflux: Improved outcomes in a high volume universitysetting. Abstract presented at Society for Vascular Surgery AnnualMeeting, 2005

3. Min RJ, Khilnani N, Zimmet SE: Endovenous laser treatment of saphe-nous vein: Long-term results. J Vasc Interv Radiol 14:991-996, 2003

4. Cabrera J, Cabrera J Jr, Garcia-Olmedo A: Treatment of varicose longsaphenous veins with sclerosant in microfoam form: Long-term out-comes. Phlebology 15:19-23, 2000

5. Stirling M, Shortell CK: Endovascular treatment of varicose veins. Se-min Vasc Surg 19:109-115, 2006

6. Kabnick LS, Ombrellino M, Agis H, et al: Endovenous heat inducedthrombus (EHIT) following endovenous vein obliteration: To treat ornot to treat? A new peri-operative thrombotic classification. Presenta-tion at the American Venous Forum 20th Annual Meeting, Charleston,SC, February 20-23, 2008

7. Merchant RF, Pichot O, for the Closure Study Group: Long-term out-comes of endovenous radiofrequency obliteration of saphenous refluxas a treatment for superficial venous insufficiency. J Vasc Surg 42:502-509, 2005

8. Pichot O, Kabnick LS, Creton D, et al: Duplex ultrasound scan findingstwo years after great saphenous vein radiofrequency endovenous oblit-eration. J Vasc Surg 39:189-195, 2004

9. Ogawa T, Hoshino S, Midorikawa H, et al: Clinical results of radiofre-quency endovenous obliteration for varicose veins. Surg Today 35:47-51, 2005

0. Manfrini S, Gasbarro V, Danielsson G, et al: Endovenous managementof saphenous vein reflux. J Vasc Surg 32:330-342, 2000

1. Weiss RA, Weiss MA: Controlled radiofrequency endovenous occlu-sion using a unique radiofrequency catheter under duplex guidance toeliminate saphenous varicose vein reflux: A 2-year follow-up. DermatolSurg 28:38-42, 2002

2. Nicolini P, the Closure Group: Treatment of primary varicose veins byendovenous obliteration with the VNUS closure system: Results of aprospective multicentre study. Eur J Vasc Endovasc Surg 29:433-439,2005

3. Salles-Cuhna SX, Comerota AJ, Tzilinis A, et al: Ultrasound findingsafter radiofrequency ablation of the great saphenous vein: Descriptiveanalysis. J Vasc Surg 40:1166-1173, 2004

4. Proebstle TM, Vago B, Alm J, et al: Treatment of the incompetent greatsaphenous vein by endovenous radiofrequency powered segmentalthermal ablation: First clinical experience. J Vasc Surg 47:151-156,2008

5. Venous Codes At-A-Glance. San Jose, CA, VNUS Medical Technologies
Inc., 2009

radiofrequency ablation: evolution of a...

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