Sclerotherapy involves the injection of a sclerosing agent for the targeted elimination of intracutaneous, subcutaneous, and transfascial varicose veins (perforating veins) and the sclerosation of subfascial veins in the case of venous malformation. Various sclerosants induce marked damage of the vascular endothelium and possibly of the entire vascular wall. After successful sclerotherapy and in the long term, the veins are transformed into a fibrous cord, a process known as sclerosis.1, 2 The purpose of sclerotherapy is not merely to achieve thrombosis of the vessel, which per se may be amenable to recanalization, but definitive transformation into a fibrous cord. This cord cannot recanalize, and the functional result is equivalent to the surgical removal of a varicose vein.

Indications

The guidelines for sclerotherapy of varicose veins of the German Society of Phlebology were slightly modified and updated with the results from recently published data.3

The objectives of sclerotherapy are:

• •Treatment of varicose veins and prevention of possible complications.
• •Reduction or elimination of existing symptoms.
• •Improvement of pathologically altered venoushemodynamics.
• •Achievement of good results that satisfy aesthetic and functional criteria.

In principle, all types of varicose veins are amenable to sclerotherapy. Particular indications are listed in Table 1.

Sclerotherapy is the method of choice for the treatment of small‐caliber varicose veins (reticular varicose veins, spider veins). For the obliteration of accessory varicose veins and incompetent perforating veins, sclerotherapy competes with percutaneous phlebectomy and with ligation of perforating veins or endoscopic dissection of perforating veins.4, 5 In the treatment of saphenous veins, surgery has been the method of choice, but treatment of truncal veins using sclerotherapy is also possible.6–8 This applies in particular to foam sclerotherapy, as studies conducted in recent years have demonstrated.9–13

Contraindications

Absolute and relative contraindications are listed in Table 2.

Complications and Risks

If performed properly, sclerotherapy is an efficient treatment method with a low incidence of complications. In therapy, a number of adverse events may be encountered. These are shown in Table 3.14–17

Allergic skin reactions occur occasionally as allergic dermatitis, contact urticaria, or erythema. Anaphylactic shock and inadvertent intra‐arterial injection are extremely rare complications constituting an emergency situation.18, 19 Transient migraine‐like symptoms occur more commonly after foam sclerotherapy than after liquid sclerotherapy.14, 17 In this context, it has been speculated that a patent foramen ovale (PFO), which is present in approximately 25% of the population, might be a factor, allowing foam bubbles to pass into the arterial circulation.18–22

Thromboembolic events [deep vein thrombosis (DVT), pulmonary embolism or stroke] occur in rare circumstances after sclerotherapy. Most of these events, diagnosed in routinely performed duplex investigations, are asymptomatic.14, 17 According to prospective studies, the risk of DVT is higher when larger volumes of sclerosant are used, particularly in the form of foam9, 23–25 and in patients with a previous history of thromboembolism or known thrombophilia.26 In patients with these risk factors, the indication for sclerotherapy must be clearly established, and additional precautionary measures must be observed.27 Single case reports of proven stroke or transient ischemic attack after liquid or foam sclerotherapy in patients with PFO have been published.17, 23, 28, 29 Multiple small‐dose injections of foam can reduce the passage of sclerosant foam into deep veins.30

Skin necroses have been described after perivascular injection of sclerosants in higher concentrations and rarely after properly performed intravascular injection with sclerosants in various concentrations, for example, with 0.5% polidocanol in the treatment of spider veins.31In the latter case, a mechanism involving passage of the sclerosant into the arterial circulation via arteriovenous anastomoses has been suggested.32 In individual cases, this has been described as embolia cutis medicamentosa.33 Extensive necroses occur after inadvertent intra‐arterial injection.31, 34 Instances of hyperpigmentation have been reported, with frequencies ranging from 0.3% to 10%.15, 35 In general, this phenomenon regresses slowly. The incidence of pigmentation is likely to be higher after foam sclerotherapy.14 Matting¯ in the area of a sclerosed vein¯ is an unpredictable individual reaction of the patient and can also occur after surgical removal of a varicose vein.31 Local paresthesia after sclerotherapy is rare.36, 37

Other transitory phenomena after sclerotherapy include intravascular clots, phlebitis, hematomas, disturbed sense of taste, feeling of tightness in the chest, pain at the injection site, swelling, induration, mild cardiovascular reactions, and nausea. Additionally, complications such as blister formation (blisters in the vicinity of an adhesive plaster) may arise because of the compressive bandage.4 Intravascular clots can be squeezed out after a stab incision to reduce the development of hyperpigmentation.

Diagnosis Before Sclerotherapy

To be successful, sclerotherapy requires thorough planning. Therefore, a proper diagnostic evaluation should be performed before treatment.3 Diagnostic evaluation includes history‐taking, clinical examination, and Doppler ultrasound investigation. Functional examinations make it possible to assess improvement in venous function, which is to be expected for the elimination of varicosis. Diagnostic imaging is especially suitable for identifying incompetent junctions with the deep venous system and for locating pathologic reflux, as well as for clarifying post‐thrombotic changes and selecting the most appropriate treatment option. In addition, sclerotherapy is an intervention that requires patients’ informed consent.

Implementation of Sclerotherapy of Varicose Veins Using Polidocanol

Polidocanol in concentrations of 0.25%, 0.5%, 1%, 2%, 3%, and 4% is licensed in Germany for sclerotherapy of varicose veins. The maximum daily dose of polidocanol is 2 mg/kg of body weight.38

Sclerotherapy with Sclerosing Solutions (Liquid Sclerotherapy)

Table 4 provides guide values for concentration and volume per injection for liquid sclerotherapy.38

A smoothly functioning disposable or glass syringe and a small‐diameter cannula are required for sclerotherapy. Cotton‐wool rolls or pads and adhesive paper tapes are used for local compression. The different techniques vary considerably. The following principles apply to liquid sclerotherapy:

• •Puncture of the veins can be performed with the patient standing or lying down.
• •The injection is usually performed with the patient in a supine position. After the vein has been punctured with the free injection needle or with the syringe attached, the intravascular position is checked.
• •Intravascular injection of the sclerosant is performed slowly and incrementally, checking that the cannula is positioned inside the vein. Severe pain during injection may be indicative of perivascular injection.
• •Immediately after injection of the sclerosant and removal of the cannula, local compression is performed along the course of the sclerosed vein.
• •After sclerotherapy, compression is applied to the treated extremity. Compression can be performed using a compression stocking and a compression bandage.
• •Local compression can be removed the same evening or the next day. Depending on the diameter and location of the varicose veins, compression is performed for hours up to several days and weeks after completion of sclerotherapy.
• •After a sclerotherapy session using the traditional technique, the patient should ambulate (physical thromboprophylaxis). Careful watch must be kept for any signs of allergic reactions.
• •Intensive sports activity, hot baths, sauna, and strong ultraviolet irradiation (solarium use) should be avoided in the initial days after sclerotherapy.

Sclerotherapy with Foamed Sclerosants (Foam Sclerotherapy)

The literature has long contained reports of sclerotherapy with foamed sclerosants.39 In recent years, as the technology has improved, foam sclerotherapy has become established, particularly for the treatment of larger varicose veins.40, 41 Detergent‐type sclerosants such as polidocanol can be transformed into fine‐bubbled foam using special techniques.

In the Monfreux technique,41 negative pressure is generated by drawing back the plunger of a glass syringe, the tip of which is tightly closed. The resulting influx of air produces large‐bubbled, fairly fluid foam.39 In the Tessari technique, the turbulent mixture of liquid and air in two syringes connected using a three‐way stopcock produces the foam. It is fine‐bubbled and fluid at low concentrations and rather viscous at high concentrations. The mixing ratio for sclerosant to air is 1:3 to 1:4. The double syringe system technique involves the turbulent mixing of polidocanol with air in a sclerosant to air ratio of 1:4 in two syringes linked using a connector. The resulting product is fine‐bubbled, viscous foam.39

The standardized transformation of a licensed liquid sclerosant into a foam sclerosant and treatment with it is permissible provided that the patient has been adequately informed about the procedure and about the benefits and risks of the method and consents to its use. Even if foam is used off‐label, the published evidence and data document the use as a standard procedure.

The Second European Consensus Conference on Foam Sclerotherapy took place at Tegernsee, Germany in April 2006. On the basis of the expert’s own experience and the available literature, the following recommendations on foam sclerotherapy were given, partially modified for the guideline.27

Puncture and Injection

When treating the great saphenous vein (GSV) by direct puncture, it is recommended that venous puncture be performed in the proximal thigh area. If long catheters are used, it is recommended that access to the GSV be made below the knee. When treating the short saphenous vein (SSV) by direct puncture, it is recommended that venous puncture be performed in the proximal or middle part of the lower leg. When treating the perforating veins, it is recommended that the injection not be made directly into the affected vein.

Foam Generation, Concentrations, and Volumes

The Tessari and Tessari/double syringe system methods are recommended for the generation of foam sclerosant for all indications. Air is accepted or proposed as the gas component for the generation of foam sclerosant for all indications. A mixture of carbon dioxide and oxygen may also be used. The preferred ratio of liquid sclerosant and gas for the generation of a foam sclerosant is 1:4 (1 part liquid to 4 parts gas). Ratios between 1:1 and 1:5 are used for reticular varicose veins and spider veins, but the majority use the 1:4 ratio. The preferred foam volumes per venous puncture are shown in Table 5, and the preferred concentrations are outlined in Table 6. The recommended maximum foam volume per leg and session (given in a single injection or in several injections) is 10 mL. When treating large‐caliber varicose veins, the foam sclerosant should be as viscous as possible.

Safety Measures

Safety during foam sclerotherapy of the GSV and SSV can be improved by avoiding immediate compression of the injected areas, using ultrasound to monitor foam distribution, injecting a highly viscous foam, and ensuring that there is no patient or leg movement for 5 minutes and no Valsalva maneuver or other muscle movement.

The known presence of a PFO indicates that sclerotherapy must be performed with special precaution. Such patients patient should remain lying down for longer (8 to 30 minutes), use only small volumes of foam (2 mL) or liquid sclerotherapy, and avoid Valsalva maneuvers.

Before foam sclerotherapy, it is not considered necessary to perform specific investigations for PFO.

A high risk of thromboembolism in the patient’s history and known thrombophilia (especially in combination with a high risk of thromboembolism) indicates that sclerotherapy must be performed with special precaution. It is recommended that, in such patients, adequate low‐molecular‐weight heparin prophylaxis (in line with relevant guidelines and recommendations) be instituted, physical prophylaxis be implemented, low sclerosant concentrations be used for foam generation, and small volumes of foam be used. The practitioner is advised to perform a benefit‐risk assessment based on the particular indication.

It is not considered necessary to perform specific investigations for thrombophilia before foam sclerotherapy.

Patient Information

Before foam sclerotherapy, patients should be informed about risks and possible adverse effects in the same way as before liquid sclerotherapy. In addition, they should be told that there is a slightly higher risk of hyperpigmentation and inflammation, there is a risk of developing (transient) neurological symptoms, there is a risk of developing (transient) visual disturbances, and there is a risk of triggering migraine.

As before liquid sclerotherapy, patients should be informed about the expected treatment outcome. In addition, they should be told that short‐term outcomes are highly satisfactory; further therapy is possible and may be necessary in some cases, especially in treatment of large varicose veins; and foam sclerotherapy is more effective than liquid sclerotherapy.

Efficacy

Numerous published clinical series and controlled clinical trials provide evidence to corroborate the elimination of intracutaneous and subcutaneous varicose veins using sclerotherapy.

In older studies with liquid sclerotherapy, surgery was significantly more effective in the treatment of saphenous varices.4 In the treatment of saphenous varicose veins, foam sclerotherapy is significantly more effective than liquid sclerotherapy.11, 13, 42–44 The immediate occlusion rate of the GSV after foam sclerotherapy reaches 70% to 95%.9–13 After 1 to 3 years of follow‐up, the occlusion rate drops to 55% to 80%.9, 11, 12, 45, 46 The occlusion rate depends on the initial diameter of the vein and the injected foam volume and concentration.13, 25 Long catheter‐assisted foam sclerotherapy of the GSV, with or without terminal balloon, seems to have slightly better occlusion rates.47–51 Foam sclerotherapy is also more effective in the treatment of venous malformations than liquid sclerotherapy.43 In the treatment of accessory varicose veins, liquid sclerotherapy is less effective than surgery.52In contrast, occlusion rates after foam sclerotherapy are better than those in saphenous veins.53 The occlusion rate after 3 years reaches 80%.53 In patients with venous ulcers, sclerotherapy of peri‐ulcer varices improves ulcer healing.54–56 Sclerotherapy is the standard treatment for intracutaneous varicose veins (telangiectases and reticular veins), allowing improvement of up to 90% to be achieved.57–60

Compression treatment with medical compression stockings may improve the results of sclerotherapy for spider veins.35, 61 The incidence of pigmentation decreases significantly.35, 62 Local eccentric compression significantly increases local pressure in the sclerosed area and improves the efficacy of sclerotherapy.63