Sclerotherapy with Adjunctive Stasis of Efflux (STASE) in Venous Malformations: Techniques and Strategies

Venous malformations are very commonly encountered in interventional radiologic practice. Indications for therapy are clearly defined based on the lesion's impact on patient's quality of life. Screening laboratory coagulation studies in patients with historical or lesion morphologic risk factors often reveal abnormal coagulation parameters consistent with localized intravascular coagulation or more severe coagulopathic states. These may require chronic or periprocedural medical management to avoid potentially life-threatening disseminated intravascular coagulation or other thromboembolic phenomena. Once a multidisciplinary decision to treat a venous malformation is made, one must decide between percutaneous and/or surgical techniques. Sclerotherapy with adjunctive stasis of efflux (STASE) techniques have become the mainstay of therapy for most venous malformations as they are well-tolerated and effective. STASE techniques work primarily by (i) the administration of sclerosant(s) exerting an inhibitory and/or endotheliocidal effect on venous malformation endothelium leading to thrombosis, involution, and fibrosis, and secondarily via adjunctive outflow occlusion using any combination of local compression, balloons, gelatin, coils, laser, radiofrequency, or adhesives to improve sclerosant penetration and dwell-time in the lesion. Adhesives alone can fill the lesion to facilitate surgical resection in some cases. Common sclerosants in modern practice include sodium tetradecyl sulfate, bleomycin, polidocanol, ethanol, and hypertonic saline. Most agents can be given directly in unmodified or "neat" form or can be mixed with a gas to form a sclerofoam or embolic such as gelatin to form a sclerogel. Choice and method of sclerosant delivery in each patient is based on the intraluminal lesion volume, architecture, vital structure proximity, agent toxicity, viscosity, and level of experience of the interventional radiologist with that particular agent. Multi-session STASE therapy usually reduces symptoms of chronic pain or mass with low risk of known complications of skin or nerve impairment, compartment syndrome, hemoglobinuria, deep venous thrombosis, or pulmonary phenomena.