Significant endothelin release in patients treated with foam sclerotherapy.

Foam sclerotherapy has been proven to be a safe and effective treatment for superficial venous insufficiency, but transient visual and neurologic disturbances continue to be reported. These side effects have been theorized to be related to the presence of air or gases in the sclerosing foam that results in "bubble" migration into the cerebral circulation. We present a differing hypothesis that significant amounts of endothelin are released from the treated veins, amounts capable of causing these complications. We tested the release of endothelin 1 (ET-1) in 12 rats after sclerotherapy with sodium tetradecyl sulfate (STS) in liquid and foam preparations. In 11 human subjects, we measured ET-1 in systemic circulation and in a draining vein after foam sclerotherapy with polidocanol. Rats treated with STS showed a significant increase in ET-1 levels 1 and 5 minutes after foam sclerotherapy. Patients treated with foam sclerotherapy showed a marked increase in ET-1 levels that correlated significantly with local ET-1 levels. Evidence of ET-1 release represents a plausible relationship explaining neurologic and visual disturbances reported after sclerotherapy.