Foamed Sclerosant Ablation of Saphenous Veins and Varices

Foamed sclerosant ablation is a safe and effective treatment for saphenous veins and superficial varicosities. Thermal ablation currently competes successfully with foam for treatment of saphenous veins in the United States, and ambulatory phlebectomy competes with foam for treatment of tributary veins and localized varicosities, especially when these are large. ^{[1, 2]}

Sclerotherapy is the chemical ablation of abnormal veins. The modern goal of therapy is irreversible fibrotic occlusion, followed by reabsorption of the target vessel. Absence of endothelium and subendothelial edema are seen within 2 minutes of foam injection. At 15 minutes, necrosis of the vein wall into the tunica media is seen. ^[3]

Sclerotherapy is an old technique that was revolutionized by technologic advances. ^{[4, 5]} Foaming detergent sclerosants offered increased potency and could be visualized by means of ultrasonography (US). US guidance allowed better anatomic visualization, greater hemodynamic understanding, more precise foam targeting and delivery, and monitoring for unwanted foam passage into deep veins. ^{[6, 7]} With these advances, sclerotherapy became a competitive treatment for any type or size of vein.

Sclerotherapy’s development has been limited somewhat by the wide range of techniques available. This practice variation has yielded varying results and has made generalizing about the procedure more difficult. The differences between techniques have now begun to be tested, however, and the resulting knowledge has improved overall results.

Two European Consensus Meetings on Foam Sclerotherapy ^[8] determined consensus opinions on the basis of the views of a panel of experienced sclerotherapy experts. European guidelines for foam sclerotherapy in chronic venous disorders were published in 2014. ^[9]

Foam can be used to treat almost any abnormal vein. It is most effective for veins less than 6-7 mm in diameter but can be effective for veins of almost any diameter if excellent technique is employed. ^[10] Sclerotherapy produces minimal procedural and postprocedural pain. It is easier to perform than most alternative strategies. Even with improved recent techniques, however, the need to repeat treatment is significant.

Currently, in the United States, endovenous thermal ablation and surgical ligation and stripping are performed more often than sclerotherapy for saphenous veins. ^{[11, 12]}  Foam sclerosants have been combined with endovenous laser ablation (EVLA). ^{[13, 14]}

Ambulatory phlebectomy is an alternative for tributary veins or localized varicosities, especially at larger vein diameters.

Surface laser therapy can be used for telangiectasias and reticular veins, but liquid sclerotherapy is considered first-line therapy for these veins on the lower extremity.

Relative contraindications for foam sclerotherapy include the following:

• Acute thrombosis
• High risk for deep venous thrombosis (DVT), as in patients with a history of multiple DVT episodes
• Allergy to sclerosants
• History of multiple drug allergies
• Inability to ambulate
• Inability to tolerate compression, as in patients with peripheral arterial disease (PAD)

Anatomy

Grossly, the venous system is composed of venules and small and great veins, which serve to return blood from tissues to the heart. The systemic venous system brings deoxygenated blood from tissues and organs back to the right atrium of the heart, whereas the pulmonary venous system brings oxygenated blood from the pulmonary circulation back to the left atrium of the heart.

The systemic venous channels are further classified as superficial veins, deep veins, or venous sinuses. The superficial, or cutaneous, veins reside just beneath the surface of the skin. They channel blood from cutaneous tissues to deep veins via perforations in the deep fascia. Most of the deep veins share routes with the arteries, and many are enclosed in the same sheaths. Venous sinuses are present only within the skull.

For more information about the relevant anatomy, see Venous Drainage Anatomy.

Procedural planning

Evaluation of the location and severity of venous disease should be carried out, and alternative diagnoses should be considered.

In patients with evidence of chronic venous disease (eg, varicose veins, telangiectasias, extremity pain or swelling worsened by standing and improved by elevation, or skin changes around the ankle area), a careful history and physical examination are necessary. Duplex US should be performed to permit assessment of the venous anatomy and hemodynamics. Superficial, perforator, and deep venous systems are examined for obstruction or reflux. Venous reflux is retrograde blood flow of over 0.5 seconds in the saphenous system.

The symptoms of chronic venous disease all have a large differential diagnosis. Because varicose veins (see the image below) produce symptoms ranging from none to severe, alternative explanations for patient symptoms should be entertained. Three related venous diseases that result in patient presentation with symptomatic varicose veins are iliac vein obstruction, pelvic congestion syndrome (PCS), and vascular malformation.

Iliac vein obstruction

Iliac vein obstruction can be caused by thrombosis or by anatomic compression of the iliac vein (usually by the iliac artery). The diagnosis is generally missed on standard lower-extremity duplex US. It should be considered in patients who have symptoms and signs that are out of proportion to the reflux seen. Patients with a history of thrombosis or duplex signs indicative of prior thrombosis are also to be at higher risk. Exercise claudication (pain with exercise) is a more specific but less sensitive symptom.

Intravascular US, magnetic resonance venography (MRV), computed tomographic venography (CTV), and standard venography are all used for diagnosis, depending on the practitioner's preference. Stent placement is often effective in relieving patient symptoms.

Pelvic congestion syndrome

Some extremity varices originate in the pelvis. PCS can produce varices at the vulva, the proximal medial thigh, the buttocks, and the perianal area. The source is typically in the ovarian or internal iliac vein systems. The pathophysiology is analogous to that of male varicocele. Pelvic pain that is worse with standing or after intercourse suggests PCS. Patients may have a history of vulvar varicosities during an earlier pregnancy. They may also have urinary frequency or irritable bowel syndrome.

US, standard venography, MRV, and CTV are all used for diagnosis, depending on practitioner preference. Typical treatment is ablation with coils with or without sclerotherapy.

Vascular malformation

Patients with evidence of a vascular malformation, such as lesions manifesting early (often at birth or puberty) or abnormal anatomy or blood flow on US, should undergo further testing, usually with magnetic resonance angiography (MRA), to determine whether the abnormality is a high-flow malformation or a low-flow malformation. ^[15]

Such malformations should be treated by a team comprising multiple disciplines, often including phlebology, vascular surgery, plastic surgery, dermatology, and orthopedic surgery. Low-flow venous malformations can often be treated successfully with foam sclerotherapy by practitioners experienced in handling these abnormalities. ^[16]

Complication prevention

Compression after foam injection improves the efficacy of the procedure and reduces the risk of DVT and superficial phlebitis. Some research suggests that there is a benefit to continuing postsclerotherapy compression for as long as 6 weeks, but these data must be balanced against the likelihood that many patients will be reluctant to comply with physician instructions for long-term compression.

The authors typically use a 20-30 mm Hg compression hose that covers the area treated (either knee high or thigh high) day and night for 2 weeks. Large varicosities are initially (ie, for the first 48 hours) compressed with a localized compression dressing of cotton gauze and self-adherent elastic wrap in the hope of reducing the risk of trapped blood.

In a randomized, controlled trial, polidocanol microfoam to be proved noninferior to nonspecific surgical therapy for treatment of saphenous vein reflux. ^[17]

In a meta-analysis, US-determined pooled saphenous ablation rates at 3 years were 77% for foam, 78% for stripping, 84% for radiofrequency ablation (RFA), and 94% for laser ablation. ^[18]

In one study, sclerofoam injection improved ulcer healing rates in patients with severe chronic venous insufficiency. ^[19]

Thermal ablation (ie, laser ablation or RFA) has been recommended over foamed sclerosant ablation for saphenous veins. ^{[20, 21]}

Neto et al evaluated the impact of US-guided foam sclerotherapy (UGFS) of the great saphenous vein (GSV) on quality of life and photoplethysmography findings for 29 legs in patients with chronic venous insufficiency who were followed for 1 year. ^[22]  They noted statistically significant improvements in quality-of-life and symptom scores and in venous filling time as measured by photoplethysmography, along with a reduction in GSV diameter, at 45, 180, and 360 days after treatment. Patient satisfaction levels were high.

In a randomized controlled trial (RCT) that included 50 patients with varicose veins, edema, and GSV incompetence (diameter, 6-10 mm), Dos Santos et al evaluated the efficacy of catheter-directed foam sclerotherapy with tumescence of the GSV (group B) against that of UGFS (group A). ^[23]  At 28 days, the full success rate for the treated GSV was 36% in group A and 80% in group B; 14 patients in group A and 3 in group B required retreatment sessions. At 6 and 12 months, success rates did not differ significantly. Complication rates were similar in the two groups. Quality of life improved in both.

In systematic review and network meta-analysis (51 articles; 36 RCTs; 7576 limbs) aimed at determining the most effective intervention for treating saphenous vein insufficiency, Gasior et al compared foam sclerotherapy, RFA, EVLA, mechanochemical ablation (MOCA), cyanoacrylate glue (CAE) closure, and high ligation and stripping (HLS). ^[24]  Although all of the interventions yielded improvements in the Venous Clinical Severity Score (VCSS), foam sclerotherapy was associated with the highest risk of recurrence.

In the FOVELASS study, a multicenter RCT that compared the outcomes of UGFS (n = 82) and EVLA (n = 79) in the treatment of isolated small saphenous vein (SSV) incompetence, Hamel-Desnos et al determined that EVLA was technically more successful than UGFS at 3 years after treatment (in agreement with similar studies assessing these modalities in the GSV); however, the two therapies yielded similar improvements in clinical outcome. ^[25]