Servier – Phlebolymphology

Abstract

Varicose veins are a part of chronic venous insufficiency syndrome, presenting with dilated veins, skin changes, and even ulceration in the lower limbs. Untreated, it can result in many complications and has an impact upon one’s quality of life. Management depends upon the stage and etiology of varicose veins. Conventional vein stripping surgery is now being replaced by minimally invasive modalities, among which endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) are the mainstays of treatment. Each procedure has its own sets of procedural technique, variants, performance, outcomes, and complications. Here, we discuss the various aspects of EVLA and RFA on varicose vein treatment.

Introduction

Varicose veins are dilated tortuous veins that have significant impact on a person’s quality of life (QOL).sup1/ For ease of communication, clinical-etiology-anatomy-pathophysiology (CEAP) classification is used to clinically classify varicose veins.² Treatment of varicose veins ranges from conservative management, pharmacotherapy, endovenous treatments, and surgery.

The size of the affected vessels determines the treatment modality—spider telangiectasias and reticular veins are best treated with foam sclerotherapy, thermocoagulation, and cutaneous lasers, whereas larger varicosities are preferably treated with surgery and microinvasive procedures, such as endovenous laser ablation (EVLA) and radiofrequency ablation (RFA).³ Nonthermal ablation techniques include sclerotherapy, glue, mechanochemical ablation (MOCA), and steam. They provide an advantage to patients with below-the-knee disease, owing to less risk of nerve injury or skin burn. MOCA is a hybrid process of using mechanical trauma and simultaneous sclerotherapy to ablate and treat varicose veins.⁴ Intradermal, subcutaneous, and perforator veins can be treated by chemical ablation of a varicose vein by intravenous injection of liquid or foam sclerosant via a method known as sclerotherapy.⁵ Cyanoacrylate glue can be used to ablate vessels as it polymerizes on contact with blood, causing vessel inflammation and fibrosis and occlusion, whereas the steam technique works via steam applied through the catheter canal, which releases thermal energy, causing vessel ablation and sclerosis.⁶ These are emerging technologies that are being explored for their use in varicose veins.

Owing to complications, such as bruising, postoperative pain, anesthesia complications, hematoma, saphenous nerve injury, and wound infection, conventional surgical stripping is gradually being replaced by new minimally invasive techniques like EVLA and RFA.⁷ Relevant contraindications of EVLA and RFA include an incompetent superficial vein diameter of less than 2 mm, history of extensive deep venous thrombosis (DVT) in the same leg, active superficial venous thrombosis in the vein to be treated, history of a prior surgical or endovenous treatment of the same leg, pregnancy, known malignancy and systemic conditions resulting in overall poor health, frailty, immobility, and known bleeding or clotting disorders.⁸ Various scores are used for assessment of severity and impact of varicose veins such as the Aberdeen Varicose Vein Questionnaire (AVVQ), the Aberdeen Varicose Vein Severity Score (AVVSS), the Chronic Venous Insufficiency Questionnaire (CIVIQ-2), health-related QOL (HRQOL), the Venous Clinical Severity Score (VCSS), and the Visual Analog Scale (VAS) for pain. We have described some of the outcomes with these scores.

Although both EVLA and RFA follow the principle of thermal ablation of varicose veins, there are fundamental differences in mechanism of ablation, devices used, procedure, outcomes, and complications. Here we discuss the principles and differences between EVLA and RFA techniques for the treatment of varicose veins.

Endovenous laser ablation

EVLA is a minimal invasive procedure in which a percutaneous laser fiber is introduced within the incompetent varicose vein resulting in nonthrombotic occlusion and inflammation of the vein.⁷ The major mechanism of EVLA is the conversion of absorbed light energy into heat either through direct absorption of the laser power emitted from the fiber into the blood and perivenous tissues or through direct contact between the fiber tip and the vein wall.⁹

EVLA is indicated in an ambulatory patient with great, small, or accessory saphenous vein reflux with surface varices, and/ or symptoms or complications related to superficial venous insufficiency. It can be used in all stages of varicose veins.¹⁰ Studies have shown better resolution of venous ulcers with EVLA. So, for stage C5 and C6 varicose veins, EVLA is generally preferred over RFA.⁷ EVLA can also be done in tributaries of sufficient length.¹¹

Operative procedure

Although it is a common practice to have an institutional operative protocol for EVLA and RFA, it’s mainly based on steps learned during training and on publications mentioning the procedures. The protocol is often tailored to the institution based on the experience with the procedures. Preoperative planning for these procedures along with access site determination is generally done by mapping the hemodynamic status of the veins via an ultrasound before and during the procedure.

EVLA is routinely performed using dilute local anesthesia, with or without supplemental oral anxiolytics, in an office setting. Buffered local tumescent anesthesia, especially cold tumescence, along with general anesthesia (GA) has shown improved immediate postoperative pain in EVLA compared with GA only.^12-14 Bupivacaine used in tumescent solution had a better outcome than the use of lidocaine and prilocaine.¹⁵

Generally taking 30-60 minutes to perform, procedure times are dependent on the length of segment treated, experience of the operator, and whether ancillary procedures, such as ambulatory phlebectomy, are done.¹⁰ For better results, it is necessary to empty the veins by external compression and Trendelenburg positioning.^16,17 After positioning, the great saphenous vein (GSV) is cannulated by EVLA laser fiber. A study mentioning protocol on EVLA mentions 100 J/cm delivered empirically to the first 3 cm distal to the saphenofemoral junction (SFJ) and 40 J/cm in remaining segments.¹⁸ Regardless of how underlying saphenous incompetence is treated, ancillary treatments, such as sclerotherapy and phlebectomy, along with compression, are typically needed to treat residual varices.¹⁰

The use of elastic compression stockings after EVLA has shown reduced severity of pain and edema postoperatively.^19,20 Use of compression stockings for longer than 2 days and eccentric compression applied by a new crossed-tape technique is suggested after the procedure.^21,22

Endovenous laser ablation variants

Commonly used laser ablator devices are the Biolitec laser machine (Biolitec), VenaCure EVLT System (Angiodynamics), Diomed D15plus (Diomed, Inc., Andover, MA), etc.⁷ A popular dedicated laser fiber for EVLA has a wavelength of 1470 nm, 980 nm, 940 nm, or 840 nm in power settings of 3-12watts. Pullback speed is adjusted to 1-4 mm/s. Thus, the combination of higher power and lower pullback velocity leads to maximum burn of the veins. Maximum temperature ranges from 91 °C to 97 °C. EVLA using a shorter wavelength (usually 980 nm) has a higher temperature by about 10 °C.9

Table I. Endovenous laser ablation (EVLA) outcomes.
AVVSS, Aberdeen Varicose Vein Severity Score; EVLA, endovenous laser ablation; GSV, great saphenous vein; HRQOL, healthrelated quality of life; RCT, randomized controlled trial; SFJ, saphenofemoral junction; SSV, short saphenous vein; VCSS, Venous Clinical Severity Score.

The limitation of EVLA is the need for uniform pullback or adjustable pullback for segments with perforators in varicose veins, which is difficult to standardize. This can result in incomplete burning or excessive burning.⁹

Radiofrequency ablation

RFA involves insertion of the RFA catheter inside the varicose vein that causes spasm of the vessel, ablation of endothelium of the vessel, and complete closure of the defective vein.⁴⁴ Radiofrequency waves are electromagnetic energy within a frequency range of 300 kHz to 1 MHz. The wave causes vibration and friction of atoms, resulting in thermal energy. The procedure was introduced in 1999; since then, the procedure has been gaining widespread acceptance and availability.¹¹

RFA can be used in all stages of varicose veins; but in stage C5 and C6, RFA is found to be slightly inferior to EVLA.⁷ Also, RFA can be combined with concomitant phlebectomy of tributaries.⁴⁵ Major advantages of this technology are cosmetically better procedures, less pain, early return to work, less scar, and less chance of infection.⁴⁶

Operative procedure

Preoperative mapping is done as for EVLA, and access site is determined. RFA too can be done under general, regional, or tumescent local anesthesia (under ultrasound guidance), and the Trendelenburg position can be used to achieve maximum vein collapse. The distance between the RFA catheter tip and SFJ should be at least 2 cm, and tumescent anesthesia is injected between GSV and skin with ultrasound guidance. There is a “standard technique,” where heating treatment is done at 85 C, in which the first 5.0 cm of saphenous vein is ablated at 1.0 cm per minute followed by the remainder of the GSV being ablated at 1 cm per 30 seconds, or “modified technique,” in which the first 5.0 cm of saphenous vein is heated and ablated at 1.0 cm per minute with the generator set at 90 °C after which the catheter is slowly and continuously pulled back at a rate of 1 cm per 20 seconds, which maintains a vein wall temperature of 90 °C. In both techniques, there is 0.5-cm overlap of each pair of segments, and the pullback is continuous until the desired vessel length is treated. When the final segment is treated, pulling off the heating element of the catheter into the sheath is avoided because it might melt the sheath. Usually, double ablation is done in the segment 2 cm distal to the SFJ, and adjunct sclerotherapy is done for residual veins.⁴⁷

There have also been studies on the use of venoactive drugs during the perioperative period to reduce pain and enhance recovery.³² Use of micronized purified flavonoid fraction (MPFF)—a venoactive drug—in the perioperative period showed reduction in pain, ecchymosis, paresthesia, pigmentation and heat-induced thrombosis, and enhanced recovery after endovenous ablation.^31,32

In recent trials, postoperative compression by superposition of stocking class I and class II after RFA under local tumescent anesthesia when done for 4 hours had lesser complications and greater reduction in leg volume then compression for 72 hours; there was no difference in venous occlusion, postoperative pain, and time to full recovery with and without postoperative compression in RFA.^33,48-50

Radiofrequency ablation variants

Popular RFA generator devices are the ClosureFast RFA system (Medtronic) preceded by the ClosurePlus catheter, Olympus Celon RFITT (Olympus Medical Systems, Hamburg, Germany), and CelonLab POWER radiofrequency generator (Celon AG Medical Instruments, Teltow, Germany); ^7,11,51 One popular RFA device is the VNUS ClosureFast device that uses RFA catheters of 60- and 100-cm lengths and which has a heating segment of 7 cm. The temperature attained during RFA is 120 °C with a duration of 20 seconds. Usual watt requirement is 10 to 20 watts. The second generation of RFA catheters, the ClosureFast was designed to improve on procedural deficiencies such as length of time and ease of the procedure. They use a segmental approach to ablation and involve activating the heating element for 20-second cycles. The heat is then automatically shut off, and the catheter is repositioned to the next treatment zone indicated by shaft markers on the catheter. The new catheter also no longer needs the saline drip and eliminates the high impedance issues caused by coagulum build up with the previous catheter. The segmental approach, sometimes referred to as segmental RFA ablation also speeds up the procedure and decreases the variability in dose delivered to the tissue. The new design also involved changes in the method of energy delivery in that the energy field was now shielded and an electrical field is not produced in the tissue, thereby reducing the potential concerns for interference with other indwelling devices, such as pacemakers, etc.⁵² They are very accurate to attain 120 °C within 3 seconds by varying wattage from 15 to 40 watts. Any deviation from this watt range and temperature will stop the radiofrequency cycle and will prompt a warning. This allows RFA to be more uniform and safer during the procedure.¹¹

Various studies have compared different RFA devices and their outcomes (Table II).^{45,48-50,53-55} When different RFA technologies—VeneFit, radiofrequency induced thermal therapy (RFITT), and endovenous radiofrequency (EVRF)— were compared, mean treatment time was faster in RFITT; pain score/discomfort at 2 weeks differed in that fewer in the EVRF group reported no problems. However, there was no difference in clinical outcome when compared at 6 and 12 months. Truncal ablation failure at 12 months was lesser with VeneFit.⁵⁵ Comparisons have also been made between direct RFA (dRFA; radiofrequency-induced thermotherapy) and indirect RFA (iRFA; VNUS ClosureFast) in which primary GSV occlusion rates were better after iRFA and EVLA than with dRFA.⁵³ In another study, the F-care (EVRF, F Care Systems, Antwerp, Belgium) method was safe and fast, but the 1-year closure rate was significantly lower than with the conventional endovenous RFA ClosureFast method.⁵⁴

Table II. Radiofrequency (RFA) outcomes.
AVVQ, Aberdeen Varicose Vein Questionnaire; dRFA, direct radiofrequency ablation; EVLA, endovenous laser ablation; EVRF, endovenous radiofrequency; GSV, great saphenous vein; iRFA, indirect radiofrequency ablation; RCT, randomized controlled trial; RFA, radiofrequency ablation; RFITT, radiofrequency induced thermal therapy; SSV, short saphenous vein; UGFS, ultrasound-guided foam sclerotherapy; VCSS, Venous Clinical Severity Score.

Discussion

Both EVLA and RFA are shown to be comparable to conventional vein stripping surgery and are advantageous in terms of being minimally invasive, with lesser postoperative complications. Many studies have been done comparing various aspects of EVLA and RFA, addressing pros and cons of both (Table III).^53,56-63 Although there were no sharp demarcations regarding use of EVLA and RFA preferencing one over the other, we have tried to explore their differences and variations in use (Table IV).^{7,9,11,16,17,56,64}

Table III. Comparison between endovenous laser ablation (EVLA) and radiofrequency (RFA) for varicose veins.
AVVQ, Aberdeen Varicose Vein Questionnaire; dRFA, direct radiofrequency ablation; EVLA, endovenous laser ablation; EVRF, endovenous radiofrequency; GSV, great saphenous vein; HRQOL, health-related quality of life; iRFA, indirect radiofrequency ablation; QOL, quality of life; RCT, randomized controlled trial; RFA, radiofrequency ablation; RFITT, radiofrequency induced thermal therapy; SSV, short saphenous vein; VCSS, Venous Clinical Severity Score.

Table IV. Major details on endovenous laser ablation (EVLA) and radiofrequency (RFA).
EVLA, endovenous laser ablation; RECOVERY, Radiofrequency Endovenous ClosureFAST versus Laser Ablation for the Treatment of Great Saphenous Reflux trial; RF, radiofrequency; RFA, radiofrequency ablation.

Cost

RFA and EVLA have the extra upfront cost of the generator and cost per case for disposables. In some cases, these can be done outside the operation theater without anesthetist or surgical assistant fees.⁵² RFA performed in the operating room was associated with net loss per case vs office-based interventions.⁶⁵ However, even though the initial setup cost was high, a cost analysis from hospitals in Michigan show that in the long run, treatment with vein stripping was associated with higher costs than RFA and EVLA. Another cost-effective analysis from the United Kingdom also showed that RFA had the highest median rank for net benefit, with MOCA second and EVLA third among varicose vein treatment options.⁶⁶ In low-resource settings, reusing the RFA catheter can also be one means for cost cutting. A study from India has shown promising results in terms of vein occlusion rates and cost cutting when the RFA catheter was reused.⁶⁷ Further studies on catheter-based interventions in an office setting and on reuse of catheters can significantly reduce the cost for treatment.

Technicalities

Although RFA and EVLA both cause thermal ablation, the mechanism of action and resulting technicality of thermal ablation is different between these 2 techniques. RFA causes a circular, homogeneous lesion, and there is no perforation of the venous wall. Whereas in laser ablation, the light energy is transmitted into heat energy, causing vascular wall disruption and venous wall perforation. The difference was studied in multiple experimental studies.^68,69 These could be the reasons for lesser postoperative pain in RFA patients. Also, RFA seems to be more dependent on adequate vein emptying, use of tumescent anesthesia, and compression techniques than EVLA techniques, which do not depend on vein wall contact.⁵² But for even better results after EVLA, it was necessary to empty the veins by external compression and Trendelenburg positioning in EVLA too.^16,17 Use of buffered tumescent anesthesia (to physiologic pH) has shown lower pain scores and analgesic use after endovascular procedures.³⁴

In relation to ease of procedure and uniformity of the ablation, RFA is much more comfortable than EVLA as there is a segmental approach of ablation and the energy automatically stops after the standard duration in desired temperature.⁵² This has made learning hands-on skills to do RFA and following the standard operating protocol much easier. In addition, the RFA catheter is much sturdier than the EVLA catheter, and there are lesser chances of physical damage to the RFA catheter during the procedure. Although not recommended, there is more possibility of reusing the RFA catheter than the EVLA catheter.⁶⁷

Technical success and redo rates

A study compared EVLA and RFA in patients with bilateral varicose veins where one limb received RFA as treatment and another limb received EVLA. Here, rate of recanalization was 6.8% in the RFA group, whereas that was not present in the EVLA group. Time to return to normal activity was 0.9 days in the EVLA group and 1.3 days in the RFA group.⁷⁰ Similarly, higher technical success and low redo rates are found with use of EVLA as compared with RFA in a study from India.⁷ When first-generation RFA catheters were used, studies showed lower technical success and higher redo rates.⁷¹ Second-generation catheters using a segmental approach to ablation have improved technical ease, speed, and effectiveness of the RFA devices.

Outcomes and complications

Many comparative studies have shown similar outcomes between EVLA and RFA in terms of safety and efficacy, including vein ablated length, GSV occlusion, pain scores, QOL, and complications after the procedures—thrombophlebitis, hematoma, edema, ecchymosis, paresthesia, and recanalization.^72-74

There are trials and studies that find EVLA superior in terms of ulcer resolution, lesser skin complications, faster return to work, patient satisfaction, and less recanalization.^7,74 EVLA has shorter procedure times and lower per treatment cost. Reported occlusion rates of EVLA generally are slightly higher than those obtained with RFA.¹⁰ However, return to work has also been found to be significantly sooner with RFA than with surgery, but not for EVLA, in a meta-analysis.⁷⁵ This might result from different ablative mechanisms that can cause vein wall perforation with EVLA (810 and 980 nm with bare tip) but not RFA. This has led to evolution of a new 1470-nm EVLA procedure with a radial fiber that is claimed to cause less pain with similar short-term efficacy.²⁸

A study has shown that chances of DVT and pulmonary embolism are slightly higher for RFA than EVLA.⁷ Large trials comparing RFA and EVLA, such as the RECOVERY trial (Radiofrequency Endovenous ClosureFAST versus Laser Ablation for the Treatment of Great Saphenous Reflux), also show that postoperative pain, ecchymosis, and swelling was lower in RFA.^11,56 EVLA may include more bruising and discomfort in the early postoperative period, although this may be technique dependent.¹⁰ RFA has less periprocedural pain, analgesic requirement, and bruising. RFA has also been shown to have less technical failure and early recovery with less postoperative pain.^59,76,77

Several meta-analyses have been done over time evaluating EVLA and RFA, but sufficient trials have not been done to give a more robust and significant answer for choosing between EVLA and RFA for varicose veins. Earlier analysis had shown both EVLA and RFA to be safe and comparable to surgical stripping with lesser procedural pain.^72,78,79 EVLA had better short-term outcomes with more occlusion and less recanalizations.⁸⁰ However, analysis of long-term follow-up of 5 years did not show a difference in outcomes between conventional surgery, EVLA, and RFA.⁸¹ A Cochrane review was done focusing on the methods of treatment of short saphenous veins only, which showed that EVLA had lower recanalization and recurrence of reflux than conventional surgery.⁸²

Guidelines provided by various societies and forums are not very specific in their recommendations. The Society for Vascular Surgery and the American Venous Forum, in a guideline issued in 2011, mentioned the role of endovenous thermal ablation for treatment of incompetent saphenous vein, but a separate recommendation for EVLA or RFA was not mentioned.⁸³ A recent guideline by the American Venous Forum in 2020 mentions the appropriateness of endovenous thermal ablation for stage C2 to C6 and does not recommended it for an earlier stage.³⁶ It is considered appropriate is for GSV, SSV, and accessory veins. The recent report also does not separate recommendation for EVLA and RFA.

Conclusion

Although both RFA and EVLA are near equally good in a large proportion of varicose vein cases, there are some instances where one method is better than the other. The RFA device has a more robust mechanism for safety, making it easier for hands-on learning experience. EVLA has been used for all stages of varicose veins, including ulcers. Technical success and outcomes are similar for both the procedures, with lesser skin complications with RFA use. Larger clinical trials and more robust guidelines are required for all aspects of EVLA and RFA use.






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