Behind The Medical Headlines

Foam Injection Sclerotherapy for Varicose Veins

• Dr R Mofidi, Department of Vascular Surgery, Royal Infirmary of Edinburgh, Edinburgh, Scotland
• Mr JA Murie, Department of Vascular Surgery, Royal Infirmary of Edinburgh, Edinburgh, Scotland

Summary

A less invasive surgical procedure has been developed for treating problematic varicose veins. In this article, requested by a visitor to the BTMH site, Dr Rafiq Mofidi and Mr John Murie provide an overview of foam infection sclerotherapy.

Declaration of interests: No conflict of interests declared

Introduction

Varicose veins are tortuous, dilated or lengthened veins in the lower limb and represent the clinical manifestation of incompetent valves in the superficial venous system. They are common, affecting 30-40% of the adult population in the UK between the ages of 30-70 years, although only some seek medical help. The disease has a wide spectrum of severity and not all treatments are applicable to all varicosities; this is certainly true for the new technique of foam sclerotherapy. Many patients have a mild cosmetic problem, while others have disabling symptoms, such as aching legs, pruritus and varicose eczema. In a minority, longstanding venous hypertension results in skin thickening, discolouration (lipodermatosclerosis) and venous ulceration. Seventy percent of lower limb ulcers are due to venous hypertension and these cause significant morbidity and health costs.

Compression hosiery is the traditional non-operative method of treating varicose veins. While it improves symptoms and venous blood flow, this improvement is restricted to the time the stockings are worn, and poor compliance is a major limitation. Surgery remains the mainstay of treatment for varicose veins, often in the form of ligation of the saphenofemoral junction (SFJ), at the groin, with stripping of the long saphenous vein (LSV), or ligation of the saphenopopliteal junction with multiple phlebectomy. These surgical procedures have recently been modified to replace the stripping element with endovenous radiofrequency ablation of the vein. A catheter is slowly drawn through the vein, heating it and causing its occlusion. Studies have suggested an 80-100% success rate after short to medium term follow-up.¹ One problem is that the new method is suitable only for non-tortuous saphenous veins, making it applicable to only one third to one half of patients with varicose veins. Laser ablation is similar to thermal ablation in concept and technique. While a good rate of LSV closure and symptom relief has been reported,² LSV tributaries inevitably remain and may be responsible for future recurrence.

It is against this background of multiple competing techniques that foam injection sclerotherapy has been proposed as a useful method of dealing with varicose veins. Injection of sclerosing agents into varicosities to induce a chemical thrombophlebitis (venous inflammation), venous occlusion and fibrosis has been a treatment for lower limb varicosities for over a century, but such unguided injection of liquid sclerosant is associated with high rates of recanalization and the overall results have not proved encouraging. This old technique has a place, but it is a small one in modern times. On the other hand, the new method of ultrasound guided injection sclerotherapy, using a foam sclerosant, seems to overcome many of the shortcomings of traditional liquid sclerotherapy. Ultrasound guidance enables the sclerosing agent to be injected with confidence into the long or short saphenous trunks, rather than into peripheral varicosities, in the hope of abolishing venous reflux. The use of foam rather than liquid allows smaller quantities of sclerosant to be used.⁴ Furthermore, foam sclerosant is very echogenic, permitting easy control of the operation using duplex ultrasound direction. Foam injection sclerotherapy has been used for primary LSV and SSV incompetence, some types of recurrent varicose veins and minor varicosities. In this last regard, however, it should be understood that it cannot be applied to reticular veins and telangiectases; these may be treated with low concentration sclerosant agents injected with the aid of magnifying loops (microsclerotherapy) but this is a different procedure that is beyond the scope of this article.

Technique of ultrasound guided foam injection sclerotherapy

Under local anaesthetic infiltration block, and with ultrasound imaging, a needle is inserted into the main affected superficial vein. The foam is injected and the process monitored under ultrasound control.^9,10 Some authors use a fine infusion catheter in order to facilitate the intraluminal injection of foam and to reduce the risk of extravasation of sclerosing agent or inadvertent intra-arterial injection.⁶ After confirmation of the intravenous position of the catheter, the vein may be emptied using the Trendlenberg position.³ Once the foam has filled the entire main superficial vein, the cephalad (central) end of the vein is depressed with the ultrasound probe for 2-5 minutes in order to retain the foam in the superficial veins and prevent leakage into the deep vein system. The foam causes inflammation of the vein wall and, eventually, obliteration of the lumen. After completion of the procedure, a class II graduated compression stocking is are worn for up to 30 days. Any residual varicosities can be treated with further injection sclerotherapy.^3,4

The foam used in the process derives from liquid sodium tetradecyl acetate (STD), the most common agent used in traditional injection therapy. Liquid STD is mixed with air to generate a dense foam, a process easily achieved simply by passing STD and air between two syringes through a three-way stopcock.⁴ The resultant foam lasts for about two minutes before turning once again into liquid. The quantity of injection used for obliteration of the LSV using the foam technique is typically between 1 and 10ml.

Outcome of ultrasound guided foam injection sclerotherapy

This type of sclerotherapy is a potentially valuable method of treatment for varicose veins. It can be performed without hospitalisation or anaesthesia, allowing the patient a rapid return to normal daily activity. Furthermore, it is cheap in comparison to almost all of the other methods of treatment available today.

But what are the results? A great disadvantage of foam injection sclerotherapy is the significant chance of recanalisation of the treated vessels, resulting in recurrence of superficial venous incompetence. Nevertheless, LSV occlusion rates of 81% at 3 years have been reported.⁵ Non-randomised comparisons of liquid and foam sclerotherapy have revealed significantly higher short and medium term LSV occlusion rates, and lower clinical recurrence rates, after foam injection sclerotherapy (8.1% vs 25% at 1 year).^5,7 Although recurrence is a significant shortcoming of any kind of sclerotherapy, including foam sclerotherapy, it should be remembered that, unlike surgery, foam sclerotherapy is a non-invasive technique that can be repeated without any real increase in the risks or complexity of the procedure. Ultrasound guided foam injection sclerotherapy has very few reported complications, but those that have been recognized include localized inflammation and haematoma formation, and, although rare, leakage of foam into the deep venous system resulting in deep venous thrombosis is an unavoidable risk.

References

1. Merchant F, DePalma RG and Kabnick LS. Endovascular obliteration of saphenous reflux: a multicenter study. J Vasc Surg 2002; 35:1190–6.
2. Beale RJ, Gough MJ. The treatment options for primary varicose veins-a review. Eur J Vasc Endovasc Surg 2005; 30:83–95.
3. Min RJ, L Navarro. Transcatheter duplex ultrasound-guided sclerotherapy for treatment of greater saphenous vein reflux: preliminary report. Dermatol Surg 2000; 26:410–14.
4. Tessari L, Cavezzi A, Frullini A. Preliminary experience with a new sclerosing foam in the treatment of varicose veins. Dermatol Surg 2001; 27:58–60.
5. Cabrera J, Cabrera Jr A, Garcia-Olmedo MA. Treatment of varicose long saphenous veins with sclerosant in microfoam from:long-term outcomes. Phlebology 2000; 15:19–23.
6. Belcaro G, Nicolaides AN, Errichi BM, Cesarone MR. Superficial thrombophlebitis of the legs: a randomised, controlled, follow-up study. Angiology 1999; 50:523.