Chemical Ablation

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Chapter 7 Chemical Ablation

Jose I. Almeida

Historical Background

Historical data suggest that chemical ablation of the great saphenous vein (GSV) using liquid sclerosant delivered percutaneously via syringe and needle will fail (recanalize) in over 50% of cases at 1 year. Sclerotherapy in Europe became less frequently performed in the latter part of the 20th century, at least in part, because of the work of Hobbs.¹ His 10-year randomized controlled study showed the clinical recurrence of varices was common in patients with truncal saphenous reflux managed with sclerotherapy.² Hobbs found that after 10 years, 71% of patients treated with traditional surgery for saphenous incompetence had a good outcome; this compared with only 6% of patients treated by sclerotherapy. Recent scientific evidence has shown that liquid sclerotherapy is not very effective at eliminating truncal saphenous incompetence and failure to eliminate reflux leads to early recurrence of varices. Scientific evidence is limited when comparing sclerotherapy and surgery due to the fact that many of the trials had methodologic flaws such as lack of evaluation by independent observers, high dropout rates, poorly defined outcomes, and the lack of intention-to-treat analyses.^3,⁴ However, despite these defects, most of the studies clearly demonstrated very high recurrence rates of varicose veins after sclerotherapy, ranging from 20% to 70%.

Investigators have shown that if endothelial damage is not extensive, thrombi will form and layer endoluminally. Some thrombus is expected because of platelet deposition and initiation of the intrinsic coagulation pathway once collagen is exposed; however, excessive thrombosis is undesirable because it can lead to recanalization of the vessel. Furthermore, excessive thrombus can lead to perivenous inflammation resulting in patient discomfort on an acute basis and unwanted pigmentation of the surrounding skin thereafter.

Etiology and Natural History of Disease

Sclerotherapy refers to the introduction of a drug into the vein lumen for the specific purpose of producing endoluminal fibrosis and subsequent vein closure. Clinically, the reason vein closure is desired is to mitigate the effects of venous hypertension caused by retrograde venous flow; however, other reasons are also present in clinical practice. The mechanism of action of sclerosing solutions is directed toward complete destruction of the endothelial cells lining the venous lumen, exposure of subendothelial collagen fibers, and, ultimately, the formation of a fibrous cord. In accomplishing this process, sclerosing agents must significantly alter the endothelium and to a lesser extent the media of the vein wall. The most important qualities that a sclerosant should possess are safety, efficacy, and lack of untoward side effects. Other important features should be the ability to produce durable and repeatable results, painless treatments, accurate placement with ultrasound guidance, ease of availability, and low cost.

The efficacy of sclerosing agents is a function of concentration and vein diameter.⁵ If the target vein diameter is greater than 3 mm, liquid sclerosants do not properly reach the vein wall secondary to dilution. Sclerosant in the form of foam has clearly improved the results of sclerotherapy. Foam is more efficacious than liquid⁶^–⁸ and is more readily monitored with ultrasound imaging. Foam is the reason chemical ablation has made a resurgence. Foam will expand and fill a vein of less than 12-mm diameter, offering better contact with the vein wall. Cabrera and colleagues⁹ published a clinical series of 500 lower limbs treated with foam sclerotherapy and reported that after 3 or more years, 81% of treated great saphenous trunks remained occluded and 97% of superficial varices had disappeared. This required one session of sclerotherapy in 86% of patients, two sessions in 11% of patients, and three sessions in 3% of patients.

Sclerosants

Sclerosing solutions are categorized as either detergent, chemical, or osmotic; in the United States, although many are used, only one drug is approved by the U.S. Food and Drug Administration (FDA). Sodium tetradecyl sulfate (STS) was originally approved by the FDA for manufacture by Elkins Sinn in 1946. Under the Elkins Sinn trade name Sotradecol, STS became the preferred agent for sclerotherapy. In Europe, the popular sclerosants are STS 1% to 3% (Fibrovein; STD Pharmaceuticals, Hereford, UK) and polidocanol (POL) 0.5% to 3% (Sclerovein; Resinag AG, Zurich, Switzerland). The sclerotherapy community is therefore limited in its choices of drug, and currently investigators are focused on two methods of enhancing sclerotherapy—one method changes the biologic behavior of the drug, and the other method alters the drug delivery system.

When Elkins Sinn discontinued production of Sotradecol in the United States in 2000, a nationwide shortage ensued. Since no other manufacturer had FDA approval to produce STS, compounding pharmacies were the only source from which physicians could obtain this agent. The shortage of STS and the stopgap role of compounding pharmacies ended in November 2004 when the FDA granted approval to Bioniche Pharma USA, Inc. (Belleville, Ontario, Canada) to manufacture STS in 1% and 3% strengths. Today, FDA-approved Sotradecol is manufactured by Bioniche Pharma in an FDA-approved facility and sold exclusively by AngioDynamics, Inc. (Queensbury, NY). In a study of compounded STS versus pharmaceutical-grade STS, several findings were reported.¹⁰ Compounded STS was found to contain measured levels of impurities, the most important of which was carbitol. Analysis of pharmaceutical-grade STS revealed no detectable levels of impurities. Although the level of STS impurity necessary to precipitate a clinical event is unknown, impurities in other drugs have been linked to significant unexpected adverse events. Concentrations of different compounded STS formulations showed significant variation when measured by an independent laboratory. In one sample, the concentration was 20% below the desired 3% concentration level.

Regarding efficacy, in the compounded STS group 45.7% of treated great saphenous veins demonstrated segments of incomplete ablation some time during follow-up. In the pharmaceutical-grade STS group, incomplete ablation occurred in only 12.5% of veins (p = .02).

Patient Selection

Sclerotherapy is a good choice for the treatment of nonsaphenous varicose veins, residual veins after surgical correction of axial vein reflux, and recurrent varicose veins secondary to neovascularization or incompetent perforating veins. Sclerotherapy is also the treatment of choice in spider telangiectasias, venectasias, and isolated reticular veins.¹¹ The mode of action is induction of irritation of the vein wall followed by inflammation and fibrosis. Different agents are used such as hypertonic glucose that act by dehydrating the endothelium and substances like ethanolamine oleate⁸ that have a detergent effect in the endothelial layer.

Operative Steps

The three different methods of injecting large veins are:

1. Fegan’s method: In this method the distal perforators are injected first followed by the proximal veins.¹² The saphenous trunk and the junctions are not injected. This is followed by prolonged strong compression with bandaging from bottom to top in order to minimize thrombophlebitis and induce fibrosis.

2. Tournay’s method: In this method the proximal points of reflux are injected, including the saphenofemoral and saphenopopliteal junctions (SFJs and SPJs, respectively). The final step is distal injection. Short periods of local compression are used.¹³

3. Sigg’s method: In this method, the most distal varicose vein is injected first, followed by proximal stepwise injection until the most proximal reflux point is reached. Following the procedure, prolonged compression is used ¹⁴ (Figs. 7-1 through 7-5).

Fig 7–1

Fig 7–2

Fig 7–3

Fig 7–4

Fig 7–5

Imaging

Recent trends have demonstrated a growing use of duplex-guided sclerotherapy, which was first described in 1989.¹⁵ It not only minimizes the chances of intraarterial injection and extravasation but also allows the estimation of the degree of spasm, length of vein treated, and position of the deep veins (Figs. 7-6 and 7-7).

Fig 7–6

Fig 7–7

Foam Sclerotherapy

A recent revolution in the treatment of venous disease has been the emergence of foam sclerotherapy. Egmont James Orbach in 1944 first proposed the use of foam generated by a simple process of shaking a sclerosant with air. However, interest faded because it could only be used for small veins owing to large bubbles and a high air-to-liquid ratio.¹⁶ The renaissance of foam sclerotherapy is credited largely to the work of Cabrera et al.¹⁷ and Monfreux et al.¹⁸ in the 1990s.

Foam for the purpose of vein wall destruction is a nonequilibrated dispersion of gas bubbles in a sclerosing solution in which the gas fraction is 0.5221 or greater. The foam is composed of tiny bubbles of gas covered by a tensioactive liquid.¹⁹ Small bubbles make the foam highly interactive, whereas large bubbles produce ineffective foam. The foam mechanically displaces the blood and comes into contact with the endothelium. Therefore, the same concentration of the sclerosant is suitable for large and small veins. There is sufficient clinical evidence to demonstrate several advantages of foam preparations over conventional liquid sclerotherapy^6,²⁰:

1. Liquid sclerosants are diluted by blood, thus reducing delivered concentration to the vein wall. Foam, on the other hand, displaces the blood and allows direct contact with the endothelium. It follows that the efficacy of a given concentration of a sclerosant can be enhanced with foam therapy.

2. There is increased safety with foam preparations as lower concentrations of sclerosants are used.

3. Extravasated foam is much better tolerated than liquid extravasation.

4. The air contained in the foam is echogenic and thus increases the visibility and accuracy of placement when performing duplex-guided sclerotherapy.²¹

Variables like type and concentration of the sclerosing agent, gas, gas-to-liquid ratio, bubble size, and time between preparation and use determine the efficacy of the agent.²¹ An ideal foam should be durable enough to allow injection before separating into gas and liquid components.²² It is accepted that microfoams with bubble diameters less than 250 µm are commonly used and the ideal effective choice (macrofoams have bubbles larger than 500 µm and minifoams have bubbles ranging from 250 to 500 µm). There are various techniques in the literature that describe effective ways to produce microfoam.

In reference to the biologic behavior of STS, Schneider and Fischer ²³ showed that endothelial damage is concentration dependent and occurs immediately after injection, with resulting rapid thrombus formation leading to vascular sclerosis. Importantly, 3% STS foam has not yielded 100% GSV closure when injected with a standard needle and syringe; therefore, catheters that can enhance the interaction of drug to vein wall are under investigation.

Foam is an option for controlling saphenous reflux in veins of less than 12 mm and has been shown to be a viable treatment for sclerosis of perforators. Foam is of value in the treatment of varicosed tributaries, tortuous vessels, and venous malformations. Foam also has limitations and carries liability concerns. In veins larger than 12 mm, the sclerosant–blood interface compromises treatment.²⁴ It has been recommended that a 10-mL limit be placed with regard to total foam volume injected because of possible paradoxical embolization via the patent foramen ovale.¹⁹ For this reason there has been some interest in maximizing sclerosant contact time with the vein wall through the use of catheters. Future studies will likely focus on maximizing results of liquid or foamed sclerosants through innovations in catheter technology. The known methods of producing foam sclerotherapy include the following:

Cabrera method: Juan Cabrera in 1997 published his 7-year experience of excellent results with special foam that is prepared with a sclerosing agent, CO₂, and an unknown tensioactive agent.¹⁷

Monfreux method: In this method, foam is produced in a glass syringe with the tip closed by a sterile plug; tension is applied by compressing the piston. While the foam is long lasting, the larger bubbles formed by this method can reduce the effectiveness of the therapy.¹⁸

Tessari method: Described in 1999 by Lorenzo Tessari, high-quality foam is produced with two disposable syringes and a three-way tap.²⁴ STS was initially described with this method. The advantages of this method are use of disposable materials, compact foam with small bubble diameter, and the ability to reconstitute the foam if the treatment session takes more time.

Frullini method: Described by Frullini and Cavezzi in 2000, the foam generation uses the same turbulence effect as the Tessari method.¹⁸ Foam is generated by a vial and syringe joined by a connector.

Comparative Effectiveness of Existing Treatments

Results of Clinical Trials

A prospective randomized control trial involving more than 800 patients over 10 years compared six treatment options: liquid sclerotherapy, high-dose liquid sclerotherapy, multiple ligations, stab avulsions, foam sclerotherapy, and ligation followed by sclerotherapy. The conclusion was that the results of foam sclerotherapy were superior to those of liquid sclerotherapy and comparable with those of surgery.²⁵

The listed complications ranged from phlebitis, skin necrosis, transient visual disturbance, and, on rare occasions, deep venous thrombosis (DVT). There have been suggestions that foam sclerotherapy may have a slightly higher rate of pigmentation, inflammation, and minimal necrosis when used in small reticular veins and telangiectasias.¹⁸ There have been uncertainties regarding the safety of foam preparations as animal studies demonstrated increased pulmonary hypertension. The stress on the human respiratory system is still unclear. The volume used per session depends on the size of the veins. No cases of DVT were reported in a prospective study of large volume foam sclerotherapy for varicose veins.²⁶

Two randomized controlled trials (RCTs) compared foam sclerotherapy with high ligation and stripping (HL/S). The first RCT showed that HL/S is superior to foam sclerotherapy using Varisolve (BTG plc, London, UK) for occlusion and elimination of reflux (86% versus 63%) but that foam sclerotherapy was superior to conventional sclerotherapy (90% versus 76%).²⁶ The second RCT showed that foam sclerotherapy combined with high ligation was less expensive, involved shorter treatment time, and resulted in more rapid recovery compared with HL/S.²⁷

Although foam sclerotherapy is used universally and has become the standard of care, foamed sclerosants can embolize to the arterial circulation via patent foramen ovale. Only three permanent adverse events from paradoxical embolization of foam have been published ^28,²⁹; however, several transient neurologic events have been reported anecdotally, and therefore foam remains controversial.

Outcomes Using Foam

A detailed review of the outcomes of ultrasound-guided foam sclerotherapy was published in 2007.³⁰ Some important publications and more recent data are discussed here. Cabrera et al.¹⁷ published a clinical series of 500 legs treated with foam sclerotherapy. They reported that after 3 or more years, 81% of treated great saphenous trunks remained occluded and 97% of superficial varices had disappeared. This required one session of sclerotherapy in 86% of patients, two sessions in 11% of patients, and three sessions in 3% of patients. No DVT or pulmonary embolism was encountered in this series.

Subsequently, a number of authors have published clinical series based on this technique including Frullini and Cavezzi,¹⁸ who reported a series of 453 patients, and Barrett et al.,³¹ who reported a series of 100 limbs. Cavezzi et al.³² subsequently published a detailed analysis of the efficacy of foam sclerotherapy in 194 patients, reporting a good outcome in 93% of patients. In fact, this technique has become widely used in southern Europe, Australia, New Zealand, South America, and the United States.³³ However, few surgeons in the United Kingdom use this method, perhaps because of limited evidence of efficacy. One series has been reported from the United Kingdom involving 60 patients in comparing surgical treatment with foam sclerotherapy combined with saphenofemoral ligation.³⁴

One randomized study of foam sclerotherapy in comparison with surgery has been published. This was a multicenter European study.²⁶ This randomized controlled trial included two separate studies: a surgical part undertaken by surgeons who randomized patients to saphenous stripping or ultrasound-guided foam sclerotherapy. In addition, sclerotherapists randomized patients to ultrasound-guided sclerotherapy conducted using either foam or liquid sclerosant. In all, 654 patients were treated during this study. Up to four sessions of ultrasound-guided foam sclerotherapy were allowed over 3 months to obliterate the saphenous trunks. After 12 months, the surgeons had eliminated truncal saphenous reflux in 130 of 176 patients (74%) by foam sclerotherapy and in 84 of 94 patients (88%) by surgery. In comparison, sclerotherapists had eliminated reflux in 239 of 254 patients (91%) by foam and 104 of 125 patients (83%) by liquid sclerotherapy. Posttreatment pain was assessed by a visual analog scale, which showed that surgery was much more painful during the first week. Normal activities were resumed after a median of 13 days in the surgery group and 2 days in the foam group. DVT was seen in 10 patients treated by foam and one patient treated by liquid sclerotherapy.

The relative efficacy of foam and liquid sclerotherapy has been investigated in a detailed study.³⁵ Patients with truncal saphenous incompetence were injected with either 2 to 2.5 mL of 3% POL liquid or foam into the GSV under ultrasound guidance on only one occasion. Obliteration of saphenous incompetence was obtained in 35% of liquid-treated patients and 85% of foam-treated patients after 3 weeks. At 2 years, 53% of foam-treated and 12% of liquid-treated patients had successful obliteration of the GSV. A further study was performed to assess the relative efficacy of 1% and 3% sclerosant foam.³⁶ Patients with truncal saphenous reflux were randomized to treatment with either 1% or 3% POL foam in a single session. An average of 4.5 mL of foam was injected in both groups. Immediate occlusion rates were 96% (3% concentration) and 86% (1% concentration). After 2 years, saphenous occlusion was seen in 69% of the 3% group and 68% of the 1% group.

In both of these studies, a rather small volume of foam was used; it was well below the maximum of 10 mL recommended in the Tegernsee document ³⁷ and the 20 mL suggested earlier in this text. This probably prejudiced the outcome but allowed the authors to demonstrate clearly the advantages of foam and lack of increased efficacy with 3% POL.

A number of papers have addressed particular problems in the management of varicose veins. Recurrent varices managed surgically have a poor outcome, with further recurrence from neovascularization as a common feature.³⁸ The clinical series mentioned found similar outcomes in primary and recurrent varices managed by foam sclerotherapy, with 88% of SFJs and saphenous trunks remaining obliterated at 11-month follow-up.³⁹ Creton and Uhl⁴⁰ have reported a combined surgical and foam sclerotherapy technique (in one session) for patients with recurrent varices, with obliteration of 93% of varices and saphenous trunks at 40-day follow-up. Perrin and Gillet⁴¹ reviewed the available literature on recurrent varices of the popliteal fossa and concluded that unless a grossly incompetent SPJ stump is present, ultrasound-guided foam sclerotherapy is the most appropriate treatment. They acknowledge that this conclusion is supported by reports of clinical series and not randomized clinical trials.

A number of papers have discussed the outcome of foam sclerotherapy in patients with venous ulceration and severe venous disease. One hundred eighty-five truncal veins were treated in 165 patients. A high proportion of veins were complicated (109 CEAP classes 4-6, 76 CEAP 1-3). There was no significant difference in occlusion rates between primary (45/60-75%) and recurrent (23/32-72%) veins; CEAP 2-3 (22/30-73%) and CEAP 4-6 (46/62-74%) veins; and veins with a diameter less than 7 mm (29/38-76%) and veins with a diameter more than or equal to 7 mm (13/23-57%). The authors concluded that foam sclerotherapy was equally effective for complicated and uncomplicated varicose veins.⁴² The clinical outcome of treatment has been reported in a number of papers.⁴³^–⁴⁵ In general, rapid healing of ulcers is reported following foam sclerotherapy, confirming that this treatment can probably achieve the same outcomes that result from saphenous obliteration in leg ulcer patients.

Pearls and Pitfalls

The major contraindication to the use of sclerotherapy is known allergy to the agent. The minor side effects seen are hyperpigmentation, pruritus, and neovascularization. Other reported side effects include night cramps, swollen foot, thrombophlebitis, and blisters.^46,⁴⁷ Sclerotherapy must be performed with caution in patients with arterial insufficiency, recent or recurrent DVT, hypercoagulability syndromes, and severe systemic diseases. Dangerous complications like intraarterial injection and thromboembolism can be avoided by following a meticulous protocol.

Complications

Systemic complications of foam sclerotherapy have been examined in some detail in view of occasional visual disturbance reported by some patients following both foam and liquid sclerotherapy.⁴⁸ Visual disturbance has been reported following the injection of a range of liquid sclerosants, although it is clear that it is far more common following foam sclerotherapy. Some serious neurologic adverse events, from which recovery was eventually complete, have also been reported.³¹ This has led to attention focusing on the effects of a patent foramen ovale. This was the subject of a study by Morrison et al.,⁴⁹ in which 20 patients with visual or respiratory symptoms following foam sclerotherapy were studied by transthoracic echocardiography during treatment. In this study, 65% of patients were found to have echoes in the left atrium after the injection of foam sclerosant. Five of nine patients who then underwent transcranial Doppler investigation during foam sclerotherapy were found to have high-intensity events in the middle cerebral artery during treatment.

Clearly, gas bubbles injected in the lower limb may reach the cerebral circulation, but the relationship to this phenomenon and the visual disturbances reported in some patients is yet to be established. Morrison et al. also reported the outcome of treating patients with foam made with CO₂ in comparison with air foam. This resulted in a substantial reduction in visual and other adverse events following treatment. It seems logical to consider moving to CO₂ foams to minimize these side effects, even if they are usually benign and resolve swiftly. In general, the number of serious adverse events is very small compared with the number of treatments performed. However, this reminds us that even minimally invasive treatments may have significant side effects and that we should take all reasonable precautions.

One study has examined the relative efficacy of minimally invasive means of treating incompetent saphenous trunks in comparison with surgical management.⁵⁰ A meta-analysis of 119 studies including 12,320 limbs was undertaken. The main outcome measure was obliteration of the saphenous trunk assessed by duplex ultrasonography at an average of 30 months following treatment.

A small advantage in favor of endovenous laser ablation was found, but the authors concluded that surgery and endovenous laser ablation, endovenous radiofrequency ablation, and ultrasound-guided foam sclerotherapy are equally effective.

Miami Vein Center Experience

At Miami Vein Center we have worked with two different chemical ablation catheter systems, each quite different in design, which enhance drug interaction with venous endothelium. At the 2006 American Venous Forum, we presented the results of 75 saphenous veins treated with an endovenous catheter with an occlusive balloon at the SFJ (VeinRx, Miami, FL). The idea was to isolate a column of 3% STS foamed sclerosant at the desired target site with a controlled dwell time of 4 minutes. The amount of drug delivered by the catheter was calculated based on vein volume of the target saphenous vein.⁵¹ Primary closure was 87% and primary assisted closure was 96% at 6-month follow-up. Three limbs (4%) were treated for asymptomatic DVT. Interestingly, in our series thrombus formed only at sites of decreased flow in duplicated femoral veins. In all three cases of DVT, the foam was forced into the femoral vein via a thigh perforator from the GSV because the balloon blocked the outflow to the common femoral vein.⁵² Also of interest in this trial was the difference that drug quality played in the role of effective ablation. Pharmaceutical-grade drug was profoundly more effective than drug prepared by a compounding pharmacy.¹⁰ In the compounded STS group, 45.7% of veins demonstrated segments of incomplete ablation (SIAs) at some time during follow-up. In the pharmaceutical-grade STS group, SIAs were observed in only in 12.5% of veins. This difference was statistically significant at p = .02.

The second catheter device, presented at the 2008 American Venous Forum, attempts to maximize the effectiveness of 3% liquid STS sclerosant by delivery under pressure, in a pulsed fashion (AngioDynamics, Inc., Queensbury, NY), to the GSV endoluminally. In a pilot study of 10 limbs followed for 1 year, we reported 80% primary occlusion.⁵³ Sixty percent of treated veins demonstrated SIAs at some point during the 1-year follow-up. This catheter does not occlude the SFJ, and one thrombus extension into the common femoral vein was observed postprocedure. The thrombus extension resolved spontaneously without anticoagulation. All treated GSVs were limited to a size of less than 10 mm in diameter.

Catheter-directed sclerotherapy (CDS) is attractive because it requires no power source. Lasers and radiofrequency generators cost about $25,000, in addition to the disposables required per case. CDS requires no delivery of time-consuming and often uncomfortable perivenous anesthesia to the extremity. Although we commonly see SIAs in follow-up after CDS, these areas are easily closed with needle injection of additional sclerosant to the affected area (assisted-closure). On balance, sclerotherapy still has a cosmetic connotation and is not reimbursed by many third party payers. Primary occlusion rates are lower than with thermal ablation of the GSV, but with adjunctive ultrasound-guided sclerotherapy, failing veins can be rescued. Thrombus identified in the deep system has been seen more frequently in our experience, as compared with thermal ablation.

Sclerotherapy for Superficial Varices and Telangiectases

Conventional liquid sclerotherapy is useful in the management of isolated small superficial varices not associated with truncal saphenous incompetence. Foam treatment has little advantage here and ultrasound guidance is unnecessary. A frequent presentation involves patients with reticular varices and telangiectases. Reticular varices can be managed surgically, but better outcomes are usually obtained with sclerotherapy. All patients should be carefully evaluated for the presence of saphenous truncal incompetence or other possible sources of varices by duplex ultrasonography. This commonly reveals an underlying problem that may lead to an unsatisfactory outcome if it is ignored.

Most saphenous trunks and varices can be managed by foam sclerotherapy where they play a significant part in the development of reticular varices and telangiectases. Small veins are probably best managed by liquid, rather than foam, sclerotherapy. Foam sclerosants tend to be very strong and can cause even more telangiectases to develop if injected overenthusiastically. After preparation of the area with 70% alcohol, small needles (25 to 33 gauge) are used to inject the veins. Treatment intervals depend on physician preference; in general, patients are seen for follow-up every 2 weeks.

Most publications mention the injection of 0.25% to 0.5% POL as being the most appropriate. STS 0.2% may also be used with similar outcomes.⁵⁴ In Europe, chromated-glycerine is commonly used, and a randomized trial has been published comparing this to POL and POL foam.⁵⁵ A good result can only be expected when the methods used by European phlebologists are followed.⁵⁶ The essence is to treat the “feeding veins” as well as the telangiectases. The feeding veins comprise the reticular veins that drain the telangiectases plus any incompetent saphenous veins. A region of telangiectases is selected and reticular veins in this area are injected with 0.5% POL liquid, injecting 0.25 to 0.5 mL at each location. Sclerosant will often enter telangiectases, demonstrating that the valves in the reticular veins are incompetent. Then, all telangiectases in the affected area should be injected with small amounts of 0.5% POL using 0.1 to 0.2 mL at each site.

If the reticular varices are not treated, a reasonable outcome will be obtained in about half of patients but may not be sustained. The other half of patients may obtain a disappointing outcome or more telangiectases may develop. The use of compression following sclerotherapy for small veins varies widely. A recent randomized trial showed that it is of value,⁵⁷ and it is advised that patients wear Class 2 compression stockings for at least 3 days after telangiectases and reticular varices have been injected. Postsclerotherapy compression can be used, although it was shown that the degree and duration of compression made no difference in recurrence rates, symptom improvement, or cosmesis.⁵⁸

In the United States, the aforementioned techniques are useful; however, STS is preferred for liability reasons.