Endovascular radiofrequency ablation for varicose veins: an evidence-based analysis.

OBJECTIVE

The objective of the MAS evidence review was to conduct a systematic review of the available evidence on the safety, effectiveness, durability and cost-effectiveness of endovascular radiofrequency ablation (RFA) for the treatment of primary symptomatic varicose veins.

BACKGROUND

The Ontario Health Technology Advisory Committee (OHTAC) met on August 26th, 2010 to review the safety, effectiveness, durability, and cost-effectiveness of RFA for the treatment of primary symptomatic varicose veins based on an evidence-based review by the Medical Advisory Secretariat (MAS). CLINICAL CONDITION: Varicose veins (VV) are tortuous, twisted, or elongated veins. This can be due to existing (inherited) valve dysfunction or decreased vein elasticity (primary venous reflux) or valve damage from prior thrombotic events (secondary venous reflux). The end result is pooling of blood in the veins, increased venous pressure and subsequent vein enlargement. As a result of high venous pressure, branch vessels balloon out leading to varicosities (varicose veins). SYMPTOMS TYPICALLY AFFECT THE LOWER EXTREMITIES AND INCLUDE (BUT ARE NOT LIMITED TO): aching, swelling, throbbing, night cramps, restless legs, leg fatigue, itching and burning. Left untreated, venous reflux tends to be progressive, often leading to chronic venous insufficiency (CVI). A number of complications are associated with untreated venous reflux: including superficial thrombophlebitis as well as variceal rupture and haemorrhage. CVI often results in chronic skin changes referred to as stasis dermatitis. Stasis dermatitis is comprised of a spectrum of cutaneous abnormalities including edema, hyperpigmentation, eczema, lipodermatosclerosis and stasis ulceration. Ulceration represents the disease end point for severe CVI. CVI is associated with a reduced quality of life particularly in relation to pain, physical function and mobility. In severe cases, VV with ulcers, QOL has been rated to be as bad or worse as other chronic diseases such as back pain and arthritis. Lower limb VV is a very common disease affecting adults - estimated to be the 7th most common reason for physician referral in the US. There is a very strong familial predisposition to VV. The risk in offspring is 90% if both parents affected, 20% when neither affected and 45% (25% boys, 62% girls) if one parent affected. The prevalence of VV worldwide ranges from 5% to 15% among men and 3% to 29% among women varying by the age, gender and ethnicity of the study population, survey methods and disease definition and measurement. The annual incidence of VV estimated from the Framingham Study was reported to be 2.6% among women and 1.9% among men and did not vary within the age range (40-89 years) studied. Approximately 1% of the adult population has a stasis ulcer of venous origin at any one time with 4% at risk. The majority of leg ulcer patients are elderly with simple superficial vein reflux. Stasis ulcers are often lengthy medical problems and can last for several years and, despite effective compression therapy and multilayer bandaging are associated with high recurrence rates. Recent trials involving surgical treatment of superficial vein reflux have resulted in healing and significantly reduced recurrence rates. ENDOVASCULAR RADIOFREQUENCY ABLATION FOR VARICOSE VEINS: RFA is an image-guided minimally invasive treatment alternative to surgical stripping of superficial venous reflux. RFA does not require an operating room or general anaesthesia and has been performed in an outpatient setting by a variety of medical specialties including surgeons and interventional radiologists. Rather than surgically removing the vein, RFA works by destroying or ablating the refluxing vein segment using thermal energy delivered through a radiofrequency catheter. Prior to performing RFA, color-flow Doppler ultrasonography is used to confirm and map all areas of venous reflux to devise a safe and effective treatment plan. The RFA procedure involves the introduction of a guide wire into the target vein under ultrasound guidance followed by the insertion of an introducer sheath through which the RFA catheter is advanced. Once satisfactory positioning has been confirmed with ultrasound, a tumescent anaesthetic solution is injected into the soft tissue surrounding the target vein along its entire length. This serves to anaesthetize the vein, insulate the heat from damaging adjacent structures, including nerves and skin and compresses the vein increasing optimal contact of the vessel wall with the electrodes or expanded prongs of the RF device. The RF generator is then activated and the catheter is slowly pulled along the length of the vein. At the end of the procedure, hemostasis is then achieved by applying pressure to the vein entry point. Adequate and proper compression stockings and bandages are applied after the procedure to reduce the risk of venous thromboembolism and to reduce postoperative bruising and tenderness. Patients are encouraged to walk immediately after the procedure. Follow-up protocols vary, with most patients returning 1 to 3 weeks later for an initial follow-up visit. At this point, the initial clinical result is assessed and occlusion of the treated vessels is confirmed with ultrasound. Patients often have a second follow-up visit 1 to 3 months following RFA at which time clinical evaluation and ultrasound are repeated. If required, additional procedures such as phlebectomy or sclerotherapy may be performed during the RFA procedure or at any follow-up visits.

REGULATORY STATUS

The Closure System® radiofrequency generator for endovascular thermal ablation of varicose veins was approved by Health Canada as a class 3 device in March 2005, registered under medical device license 67865. The RFA intravascular catheter was approved by Health Canada in November 2007 for the ClosureFast catheter, registered under medical device license 16574. The Closure System® also has regulatory approvals in Australia, Europe (CE Mark) and the United States (FDA clearance). In Ontario, RFA is not an insured service and is currently being introduced in private clinics.

METHODS

Literature Search The MAS evidence-based review was performed to support public financing decisions. The literature search was performed on March 9th, 2010 using standard bibliographic databases for studies published up until March, 2010.

INCLUSION CRITERIA

English language full-reports and human studies Original reports with defined study methodologyReports including standardized measurements on outcome events such as technical success, safety, effectiveness, durability, quality of life or patient satisfaction Reports involving RFA for varicose veins (great or small saphenous veins)Randomized controlled trials (RCTs), systematic reviews and meta-analysesCohort and controlled clinical studies involving ≥ 1 month ultrasound imaging follow-up

EXCLUSION CRITERIA

Non systematic reviews, letters, comments and editorials Reports not involving outcome events such as safety, effectiveness, durability, or patient satisfaction following an intervention with RFAReports not involving interventions with RFA for varicose veinsPilot studies or studies with small samples (< 50 subjects)

SUMMARY OF FINDINGS

THE MAS EVIDENCE SEARCH ON THE SAFETY AND EFFECTIVENESS OF ENDOVASCULAR RFA ABLATION OF VV IDENTIFIED THE FOLLOWING EVIDENCE: three HTAs, nine systematic reviews, eight randomized controlled trials (five comparing RFA to surgery and three comparing RFA to ELT), five controlled clinical trials and fourteen cohort case series (four were multicenter registry studies). The majority (12⁄14) of the cohort studies (3,664) evaluating RFA for VV involved treatment with first generation RFA catheters and the great saphenous vein (GSV) was the target vessel in all studies. Major adverse events were uncommonly reported and the overall pooled major adverse event rate extracted from the cohort studies was 2.9% (105⁄3,664). Imaging defined treatment effectiveness of vein closure rates were variable ranging from 68% to 96% at post-operative follow-up. Vein ablation rate at 6-month follow-up was reported in four studies with rates close to 90%. Only one study reported vein closure rates at 2 years but only for a minority of the eligible cases. The two studies reporting on RFA ablation with the more efficient second generation catheters involved better follow-up and reported higher ablation rates close to 100% at 6-month follow-up with no major adverse events. A large prospective registry trial that recruited over 1,000 patients at thirty-four largely European centers reported on treatment success in six overlapping reports on selected patient subgroups at various follow-up points up to 5 year. However, the follow-up for eligible recruited patients at all time points was low resulting in inadequate estimates of longer term treatment efficacy. The overall level of evidence of randomized trials comparing RFA with surgical ligation and vein stripping (n = 5) was graded as low to moderate. In all trials RFA ablation was performed with first generation catheters in the setting of the operating theatre under general anaesthesia, usually without tumescent anaesthesia. Procedure times were significantly longer after RFA than surgery. Recovery after treatment was significantly quicker after RFA both with return to usual activity and return to work with on average a one week less of work loss. Major adverse events occurring after surgery were higher [(1.8% (n=4) vs. 0.4% (n = 1) than after RFA but not significantly. Treatment effectiveness measured by imaging defined vein absence or vein closure was comparable in the two treatment groups. Significant improvements in vein symptoms and quality of life over baseline were reported for both treatment groups. (ABSTRACT TRUNCATED)