CHAPTER 86 Endovenous Vein Ablation
Primary venous insufficiency is characterized by the development of varicose veins of the lower extremities. The great saphenous vein (GSV) is the largest and longest vein of the superficial venous system, and reflux in the GSV is often associated with the development of large superficial varices. In addition to cosmetic issues and symptoms of leg pain and fatigue, varicose veins can give rise to ambulatory venous hypertension with its associated skin changes and ulceration. In fact, up to 80% of leg ulcers are due to venous disease. If incompetence of the saphenofemoral junction (SFJ) or a perforator vein is detected, treatment is medically indicated. In addition, reflux in other veins such as the small saphenous vein (SSV), anterior accessory saphenous vein, and vein of Giacomini may contribute to the development of varicose veins. This chapter describes ultrasonography-guided percutaneous techniques for treating patients with varicose veins who are ambulatory and whose sonographic findings include the documentation of reflux.
Knowledge of lower extremity duplex ultrasonography is an absolute necessity for the performance of these procedures. The venous anatomy is described in Chapter 92, Sclerotherapy. Patients need to be evaluated before surgery with ultrasonographic mapping and marking, during surgery with guiding and checking, and after surgery for response to treatment. Mapping refers to diagramming the findings on the patient’s chart. Marking pertains to outlining vein findings on the patient’s skin. Intraoperative guiding and checking refers to proper performance of the procedure and proper instrumentation and application of tumescent anesthesia. Response to treatment is assessed at 1 week, 1 month, and longer intervals as needed to determine the effectiveness of the procedure.
Commonly referred to as “ultrasonography-guided sclerotherapy,” endovenous chemical ablation (ECA) involves injecting a sclerosing solution under ultrasonographic guidance directly into the lumen of the vein being treated. Even if the vein has significant tortuosity the sclerosant (liquid or foam) will distribute itself within the vein lumen. An example is the use of ECA in the treatment of patients with groin neovascularization—a phenomenon seen in patients who have previously undergone surgical vein stripping. As such, ECA is especially helpful in treating these patients with postsurgical recurrences and an anatomically variable SSV with its associated tortuous tributaries. Equipment needed is very similar to that used for basic injection–compression sclerotherapy, with the addition of a 7.5- to 15-MHz linear-array ultrasound transducer. Ultrasonography provides real-time feedback to confirm intraluminal placement of the needle tip or catheter, intraluminal injection without extravasation, and attainment of the treatment end point (i.e., vasospasm; Fig. 86-1). Vasospasm is an indicator of the immediate efficacy of the foam injection; however, the final therapeutic effects of foam sclerotherapy should be evaluated clinically according to symptoms and follow-up duplex ultrasonography. Tumescent anesthesia is not required. Graduated class II (30 to 40 mm Hg) compression stockings need to be worn continuously for 24 to 36 hours, then during the daytime for 6 days postinjection.
The direct needle injection technique involves ultrasonographic visualization of the vein in a longitudinal plane (Fig. 86-2). A 21- to 25-gauge, 1- to -inch needle is inserted obliquely into the lumen of the vessel with the bevel directed up. Slow aspiration is performed to verify correct needle placement. A small amount (1 to 2 mL) of sclerosant foam or liquid (1% to 3% sodium tetradecyl sulfate [STS]) is injected slowly; a “snowstorm” sonographic pattern is appreciated on injection (Fig. 86-3).
Figure 86-3 “Snowstorm” pattern (arrow) after injection.
(Courtesy of John Mauriello, MD, Bradenton, Fla.)
Although liquid sclerosants can be used, for larger veins the effect of sclerotherapy is enhanced by creating a sclerosant foam. Foam is created using the Tessari technique (Fig. 86-4). The Tessari technique involves using one syringe with liquid detergent sclerosant (e.g., STS 0.1% to 3%, polidocanol 1% to 2%, and others) and another syringe with air. The ratio of air to sclerosant is 4 : 1. The syringes are connected by a two- or three-way stopcock. By forcing the air and fluid back and forth numerous times, foam is created. The sclerosant is supposedly concentrated on the bubbles and thus has greater potency, leading to more efficacious treatment. The foam reconstitutes into liquid very quickly, within a matter of minutes, so it needs to be injected rather quickly. Although not mandatory, using rubber-free and Silicone-free syringes (e.g., B. Braun Injekt) prolongs the foam state. This technique is simple and economical and produces good-quality foam. Ultrasonography will demonstrate more of a “snowstorm” pattern when foam is injected. Amounts and concentrations depend on the size and number of veins injected. Although foam can be used for telangiectases, complications may be more frequent and hence the technique is more commonly reserved for larger veins.
Whether foam or liquid is used, injections are administered with the patient supine, starting in the distal leg and progressing proximally to the point of reflux in order to minimize the volume of sclerosant and number of injections. Alternatively, injections can be administered starting 8 to 10 cm distal to the point of reflux, then proceeding from proximal to distal as previously injected segments undergo vasospasm. If 3% liquid STS is used, the maximum amount of solution during a treatment session is 10 mL. If foam is used, the volume limit is 10 mL of foam sclerosant as well, regardless of the concentration of the liquid detergent sclerosant used to create the foam (Breu and colleagues, 2008).
The syringe-and-needle technique is technically less difficult than the catheter infusion technique; however, it has a narrower margin of safety. This is due to the need for multiple injections and the potential for vein laceration and subsequent sclerosant extravasation.
The catheter infusion technique involves the introduction of a peripherally inserted central catheter line or a 2.5-inch, 18-gauge intravenous catheter fully inserted directly into the lumen of the vein. The catheter tip is initially located 8 to 10 cm distal to the point of reflux (Fig. 86-5). The sclerosant is injected slowly as the catheter is withdrawn. Subsequent percutaneous catheter placements are made distally and injections are directed cephalad as previously injected segments undergo vasospasm. Often, incompetent perforator veins do not require direct injection because they respond to treatment of the overlying superficial vein.
NOTE: When using the catheter infusion method, venipuncture sites are placed sequentially moving distally, with injections of the foam directed proximally (cephalad). When using the syringe-and-needle technique, injections are made from proximal to distal, with injections also directed cephalad.
Complications of ECA include those that may occur with standard injection–compression sclerotherapy. Deep venous thrombosis (extremely rare—incidence is between 0% to 5.7%) may occur if sclerosant finds its way into the deep venous system, especially in cases of inadequate post-ECA compression and lack of ambulation. Other side effects reported after ECA include transient visual disturbances, with no long-term visual or neurologic sequelae reported to date. Intra-arterial injection—the most feared complication of sclerotherapy—has been reported more frequently in association with ECA. This can cause severe skin necrosis; limb amputations have been reported as well. Therefore, performance of ECA must not be undertaken lightly. Detailed knowledge of the vascular sonographic anatomy is essential to perform ECA properly, safely, and effectively.
Over the past several years, in addition to ECA, there has been the introduction of newer procedures in the treatment of chronic venous insufficiency. Endovenous radiofrequency ablation (RFA) and endovenous laser ablation (ELA) have emerged as less invasive and more effective alternatives to vein stripping. Performed in an office setting using tumescent anesthesia, these procedures can often be completed in under 1 hour. Procedure times depend on how long it takes to access the vein percutaneously, the length of the vein, and whether it is necessary to perform any ancillary procedures such as sclerotherapy or ambulatory phlebectomy. Graduated compression stockings are required post-treatment, as they are for ECA.
With RFA, radiofrequency energy is delivered to the vein lumen to heat, shrink, and occlude refluxing saphenous veins. Occlusion results from the contraction of collagen in the vein wall. VNUS ClosureFAST (VNUS Medical Technologies, San Jose, Calif) uses a specially designed catheter to treat 7-cm segments of the vein while maintaining intraluminal temperature at 85° C to 90° C (Fig. 86-6). A 35-cm-long vein can be treated in 2 minutes. With ELA, laser energy of varying wavelengths is delivered to the vein lumen. Examples of wavelengths used for ELA include 810 nm (AngioDynamics, Latham, NY), 980 nm (Biolitec, East Long Meadow, Mass, and AngioDynamics, Latham, NY), and 1320 nm (CoolTouch, Roseville, Calif). Laser treatment generates steam by heating blood inside the vein, producing fibrosis and subsequent occlusion of the vein. Deoxygenated hemoglobin is the main chromophore of the 810- and 980-nm lasers, whereas the energy of the 1320-nm laser is directed toward water in the vein wall. If treatment failure (recanalization) occurs (10%), it usually develops within the first year. If the vein is closed at 1-year follow-up, it is unlikely to recanalize.