New Approaches for the Treatment of Superficial Venous Reflux and Symptomatic Varicose Veins

Introduction

Successful treatment of symptomatic varicose veins requires a balance between treatment of the underlying etiology and achievement of an optimal cosmetic outcome. In the overwhelming majority of cases, saphenous vein reflux is the primary problem. This superficial venous reflux must be addressed, or recurrence of the varicosities can be expected. In many cases, the varicose veins causing symptoms in the distribution of either the greater or lesser saphenous vein (GSV/LSV) do not need to be excised if the incompetent saphenous vein has been successfully ablated. Current minimally invasive strategies designed to eliminate reflux within the saphenous vein include endovenous radiofrequency ablation and endovenous laser ablation. Foam sclerotherapy also holds promise for the treatment of saphenous vein reflux. Remaining varicose veins can be treated later with stab avulsions, transilluminated powered phlebectomy or sclerotherapy.

Minimally Invasive Treatment of Saphenous Vein Reflux

Minimally invasive endovenous radiofrequency and laser procedures require an initial capital investment for equipment. Also, there will be an acquisition of new disposable items that are specific to each procedure. Duplex ultrasound is utilized during the procedure to identify anatomy and assist with infiltration of tumescent anesthesia. Correct identification of the saphenofemoral junction/saphenopopliteal junction (SFJ/SPJ) with duplex ultrasound is essential to appropriately positioning the ablation/laser catheter. These new endovenous techniques require the treating physician to have ultrasound imaging skills and detailed knowledge of venous anatomy.

Radiofrequency Ablation (RFA)

The Closure procedure (VNUS Medical Technologies, Inc., San Jose, California) is a novel, endovascular, computer-feedback-controlled application of bipolar electrothermal energy that ensures transmural heating of the treated vein wall while minimizing thermal spread to neighboring tissues.^1,2 In most cases, the greater or lesser saphenous vein can be accessed in a percutaneous fashion with cut-down reserved for the difficult-to-access vein. This is a catheter-based procedure in which the saphenous vein is ablated from within by resistive heating.^1,2 Bipolar delivery of radiofrequency (RF) energy directly to the vein wall causes resistive heating that results in total loss of vessel wall architecture, disintegration, and carbonization.^3,4 The device provides continuous impedance and vein wall temperature feedback to a computer generator that allows the operator to vary catheter pull-back speed to ensure effective radiofrequency ablation of the vein.^1,2

Numerous studies have demonstrated that the Closure procedure is an effective surrogate for surgical stripping. The VNUS system has two main components. The catheter is a sterile, single-use disposable device with sheathable electrodes and a thermocouple at the tip. The catheter comes in two sizes, 6 Fr and 8 Fr, and the tip provides continuous temperature feedback to the RF generator.^1,2 Each catheter also has a central lumen that facilitates through-catheter cannulation with a 0.025” guidewire. This feature is handy for the occasional case in which the catheter does not easily pass from the insertion site to the SFJ. The 6 Fr catheter has four fanned electrodes that can expand from 2–8 mm in diameter, and the 8 Fr catheter has six paired electrodes with an expansion range between 4 and 12 mm.^1,2 The electrodes are designed to engage the intima of the vein wall at the range of diameters of each catheter. Once the electrodes engage the intima, controlled resistive heating causes shortening and thickening of the collagen fibrils as the catheter is slowly withdrawn from its insertion site.^1,2 This process ultimately leads to permanent closure of the treated vein.

The second component of the Closure system is the RF generator. This compact unit recognizes each catheter and selects the appropriate algorithm to effect vein closure.^1,2 The generator has a test button that confirms electrode contact with the vein wall. For instance, “test” numbers would be lower than expected (“normal” at the SFJ for the 6 Fr catheter is > 200 ohms, 8 Fr > 150 ohms) if the catheter was in the large-caliber common femoral vein. These numbers might approximate those seen when the electrodes are opened in saline (100–150 ohms for the 6 Fr catheter and 40–70 ohms for the 8 Fr catheter). During actual treatment, ohms will be > 150 with the 6 Fr catheter and above 100 with the 8 Fr catheter. The RF generator maintains the set temperature with as little wattage as is possible, capped at 6 watts.^1,2 If the temperature or impedance exceed limits set within each catheter’s algorithm, the operator is notified with a displayed error message on the generator. If the condition continues, the RF generator will automatically switch off. Common conditions that disrupt the algorithms include poor vein wall contact by catheter electrodes or thrombus/coagulum at the thermocouple tip.^1,2

The mechanics of the endovenous procedure are relatively straightforward with a few caveats. The treated vein should be relatively straight, free of severe tortuosity or thrombus and without aneurysm. Contraindications include a post-phlebitic vein that cannot be accessed, a mega-saphenous vein (>12 mm) and significant dilation of the proximal saphenous vein with an “aneurysmal” SFJ/SPJ.⁵ Table position should change from reverse Trendelenburg to dilate the vein as the catheter is passed toward the SFJ, to Trendelenburg, to empty the vein during treatment. If there is any question about the location of the catheter in relation to the SFJ or SPJ, it would be better to abandon RFA versus potentially injuring the common femoral or popliteal vein or applying RF energy to surrounding tissue outside the vein wall. Finally, it is wise to clearly document reflux in the saphenous vein to be treated, otherwise reimbursement for the procedure may be denied by the insurance carrier. Vein cannulation is facilitated by temporary and gentle application of a 1” Penrose tourniquet above the knee and the patient in the reverse Trendelenburg position.

Following guidewire and catheter exchange, a 6 or 8 Fr Closure sheath can be advanced over the wire into the saphenous vein. A pressurized infusion of heparinized-saline at 250 cc/hr should be established through the central lumen of the Closure catheter before insertion into the sheath. This helps to prevent thrombus formation on the thermocouple tip and electrodes. The radiofrequency Closure catheter (6 or 8 Fr) is then introduced into the sheath and passed proximally to place its tip approximately 1 cm inferior to the SFJ. This position will be seen by duplex ultrasound as just inferior to the superficial epigastric vein (SEV).

Some studies have suggested that the remaining patency of the SEV reduces risk of thermal injury to the common femoral vein.¹ An over-the-wire technique utilizing a long 0.025” guidewire can also be used at this juncture for the occasional need to traverse challenging saphenous vein anatomy. The catheter position is confirmed by duplex ultrasound imaging, and then the course of the greater saphenous vein from the SFJ to ~10 cm below the knee is anesthetized by tumescent infiltration of 1% lidocaine with epinephrine. Duplex ultrasound is essential for this part of the procedure, as the tumescent anesthetic is more effective if the delivery needle (20-gauge spinal needle) pierces the fascia that envelopes the saphenous vein. Infiltration of fluid within (or even above) the enveloping vein fascia will quickly increase the distance between the vein and the skin. This distance should be > 1.5 cm to provide a “heat sink” that reduces the risk of thermal injury to adjacent saphenous nerve and skin.¹

Tumescent anesthesia also contributes to vein spasm, which helps to eliminate blood flow within the treated vein.¹ The patient is now placed in Trendelenburg position and a final catheter position check should be made at the SFJ. Temperature and impedance results of the “test” button on the generator should now be appropriate for the chosen catheter. The RF generator can then be activated, and after the electrodes have heated, slow withdrawal of the catheter can proceed at a rate that keeps the vein wall temperature within 3ºC of the temperature set point, and the generator output well below its 6-watt maximum power. When the RF generator temperature is set to 85ºC, catheter pullback speed should be ~ 2.5 cm/min. However, if the temperature is set at 90ºC, the pullback speed can increase to 4.0 cm/min, which significantly decreases treatment time. In general, treatment time ranges between 8.5 and 12.5 min for closure of the GSV from the SFJ to the proximal leg level. The vein is usually treated to the proximal calf or knee crease.

After treatment, the catheter and cannula are withdrawn from the saphenous vein and hemostasis established with direct pressure. Repeat duplex imaging is a bit cumbersome at this stage due to the tumescent anesthetic and vein spasm. However, it usually shows no flow over the entire length of treated greater saphenous vein. An appropriately treated vein wall appears edematous when initially imaged with duplex ultrasound.^1,2 Imaging studies done early after the Closure procedure have shown vein wall shrinkage ranging from 65–77%.¹ In addition, there may be a minimal amount of color flow present through a small flow channel, but the vein usually thromboses completely shortly thereafter.¹

It is wise to re-scan the SFJ/SPJ and treated vein within 72 hours of treatment to ensure that none of the saphenous vein thrombus has propagated into the femoral or popliteal vein and that the treated saphenous vein is non-compressible (i.e., appropriately closed). If the initial postoperative duplex scan shows a thrombosed vein and no thrombus in the femoral vein, there is little to be gained by early repeat scanning. The treated vein is then re-scanned at 3, 6 and 12 months postoperatively to ensure continued closure. Usually these imaging studies demonstrate progressive vein wall contraction until the vein actually disappears as a definable ultrasound structure.¹ At 12 months, over 85% of treated veins are no longer detectable with duplex ultrasound.^1–5

There is growing clinical evidence indicating that RFA of the saphenous vein is beneficial.^4–13 Registry reporting of short- and long-term Closure results contribute additional supporting data.^5,8,13 At up to 5-year follow-up, reported results from ablation of the saphenous vein are as good or better as those from conventional surgical treatment.¹³ Imaging studies show that the treated saphenous vein disappears as a defined ultrasonographic object after the 2-year point.¹¹ Advantages of the procedure include the fact that there are no surgical wounds requiring suture closure and there is minimal-to-no postoperative pain. Clinical observations suggest that patients are much more comfortable in the early postoperative period and experience quicker recovery after saphenous vein ablation compared to surgical stripping.^{4–8,10–15}

One study that compared VNUS Closure to stripping noted that there was also a cost saving for employed patients after Closure because sick leave was shorter and physical function was more quickly restored.¹⁰ Registry data and multiple clinical studies clearly demonstrate that obliteration of the saphenous vein and the specific goal of endoluminal treatment of venous reflux are positively affected by the VNUS Closure technique. Follow-up to 5 years shows that RFA accomplishes this objective. Laser light energy has also been used to achieve this goal in place of RF energy, but its efficacy has not yet been proven in large clinical trials. Two final issues that remain unsettling at present are late re-opening of a previously closed saphenous vein and whether there will be varicose vein recurrence after saphenous vein obliteration without SFJ venous tributary disconnection. Some authors have suggested that the Closure procedure prevents subsequent neovascularization in the groin, and there are some centers that have reported no neovascularization in the absence of a groin incision.⁴

Endovenous Laser Therapy (EVLT)

The endovenous laser is currently approved by the U.S. Food and Drug Administration for the treatment of GSV reflux.^16–19 Eight-hundred ten nm wavelength laser energy is delivered via a 600-micro m fiber. The laser causes the blood to boil, which results in steam bubbles.¹⁸ This causes collagen contraction and endothelial damage. The result is thickening of the vein wall and contraction or thrombosis of the lumen. The use of diode laser energy to ablate the saphenous vein is a method that obviates the need for general anesthesia and is associated with less pain than traditional surgical stripping of the greater saphenous vein. EVLT can be performed in an office-based setting, using local anesthesia, following preoperative assessment with duplex ultrasound. Similar to the Closure procedure, it is important to identify abnormalities of the greater saphenous vein with duplex, as well as to accurately determine vein diameter. Ultrasound guidance is used to access the greater saphenous vein at the level of the knee. A 0.035-inch j-tipped guidewire is then introduced into the vein and passed to the level of the proximal saphenous vein. A 5 Fr introducer sheath (Cook, Inc., Bloomington, Indiana) is then inserted into the vein. The sheath should be of appropriate length to match the length of the treated GSV. Position of the sheath at the SFJ is confirmed with ultrasound and non-pulsatile blood withdrawal. A sterile, bare-tipped, 600-micro m diameter, 810-nm laser fiber (Diomed, Andover, Massachusetts) is then positioned approximately 1 cm below the saphenofemoral junction and just inferior to the SEV. Confirmation of the position of the laser tip is done using both duplex ultrasound and by visualizing the red aiming beam through the skin. The tissue surrounding the GSV is then infiltrated with tumescent anesthetic. The vein is compressed manually to oppose the vein walls and aid in the obliteration of the lumen. The laser is then slowly withdrawn with subsequent obliteration of the GSV. Postoperatively, compression stockings are worn for one week. Patients are allowed to resume normal activities after the procedure. The short- and mid-term results of EVLT are reported as excellent.^16–18,20 Complications are similar to those that have been reported after the Closure procedure.¹⁶ Ecchymosis and mild discomfort can be expected after EVLT; however, resolution of these minimal, but patient-discomforting, postoperative findings usually occurs by one month. The Mayo Clinic recently reported their early results, closure rates and complications of both EVLT and RFA techniques.²⁰ At one month, they demonstrated an overall success rate of 94% in closing the saphenous vein using either technique. They stated that EVLT was associated with a slightly higher vein occlusion rate; however, postoperative complications were more common after EVLT. They also recommended early postoperative duplex scanning to rule out proximal extension of thrombus and to confirm vein occlusion.

Foam Sclerotherapy

Agents that damage the venous endothelium and subsequently cause obliteration of the vein lumen are not a novel concept. Sclerotherapy is highly effective in the treatment of small varicose veins and reticular veins. However, standard sclerotherapy has been disappointing in the treatment of large superficial veins. This is likely due to inadequate sclerosant injected in the GSV or LSV, for fear that the sclerosant will reach the deep system and cause complications. Orbach introduced the concept of sclerotherapy utilizing an intravenous air block a half-century ago.²¹ Utilizing foam sclerotherapy, the dilution of the sclerosant with blood in larger veins is reduced. An air block is formed which halts blood flow in the vein. The surface area of the sclerosant is larger, and therefore the agents are more effective. Foam sclerotherapy is gaining acceptance in Europe and several new sclerosing agents are being developed. Presently, there are no foam sclerosants commercially available. However, foam sclerotherapy can be performed by mixing currently approved sclerotherapy agents with air to create microfoam. Patients must have no contraindications to sclerotherapy. Ultrasound guidance is utilized to identify the saphenous vein. Local anesthesia in the skin at the site of injection can be used to decrease pain. The saphenous vein is then injected with the foamed sclerosant. External compression at the SFJ can prevent entry of the agent into the deep venous system, and compression dressings are then placed. The procedure is associated with very little discomfort and can be performed on an ambulatory basis. Minor complications of the procedure are reported to be pigmentation and superficial thrombophlebitis. However, more serious complications can include anaphylaxis and intraarterial injection.^21–24 Cabrera et al.²² demonstrated that foam sclerotherapy was effective in treating varicose veins with saphenous reflux in 86% of patients. Single treatment of foam sclerotherapy utilizing ultrasound guidance was effective in obliterating the greater saphenous vein in 81% of cases, and in eliminating varicose veins in 96% of cases. Re-treatment was necessary in only a few cases. Other authors have also demonstrated excellent long-term results in the treatment of greater and lesser saphenous vein reflux using this technique. In one study, elimination of reflux was noted in virtually all patients at 3-, 6- and 12-month follow-up.²³ The VEDICO trial compared the treatment of varicose veins utilizing several techniques including sclerotherapy, surgery and foam sclerotherapy.²⁴ This trial demonstrated that foam sclerotherapy was as effective as surgery in the treatment of varicose veins.²⁴ Foam sclerotherapy holds great potential. The expensive equipment required to perform RF ablation and EVLT are unnecessary for foam sclerotherapy. Minimal anesthesia is required and the procedure can be office-based in essentially all practices. The procedure is relatively simple to perform and will become a useful extension to the aforementioned endovenous techniques and to standard sclerotherapy.

Conclusion

New, minimally invasive techniques for the treatment of superficial venous reflux and symptomatic varicose veins including RFA, EVLT and foam sclerotherapy, represent effective alternatives to traditional saphenous vein stripping and stab avulsion of varicose veins. Further experience with these procedures will help to determine which will become the method of choice for treating this complex disease process. Some of these new techniques may not prove to be effective in the hands of all treating specialists. However, it is very likely that some of these techniques, such as foam sclerotherapy, will replace the procedures that we currently utilize today.