Sclerotherapy for slow-flow vascular malformations: An international survey of practice patterns and periprocedural management

Background: Slow-flow vascular malformations (SFVMs) are rare congenital anomalies that cause significant morbidity. Currently, no evidence-based therapy exists to improve SFVM symptoms and reduce its relapse in the long-term. Sclerotherapy is central to management and widely practiced, yet comprehensive international data are limited and no standardized guidelines exist. We aimed to evaluate current practice patterns, focusing on sclerotherapy and multidisciplinary care. Methods: An international cross-sectional survey was distributed to experts in the International Society for the Study of Vascular Anomalies (ISSVA) network. The questionnaire addressed treatment indications, sclerosant use and availability, anesthesia, coagulation management, risk communication, and case-based decision-making. Responses were analyzed descriptively. Results: Fifty-two physicians from 16 countries completed the survey. Respondents included interventional radiologists (69%), vascular medicine specialists (15%), and pediatric surgeons (8%) in academic centers (90%). Multidisciplinary consultation was reported by 92% of participants. Ethanol (67%), bleomycin (58%), and polidocanol (52%) were the most accessible, although ethanol was consistently rated as the most dangerous. Sclerosant choice varied by lesion type and scenario. The risks most frequently communicated were skin necrosis (92% for lymphatic malformations and 94% for venous malformations, respectively), pigmentary changes (70% and 75%), and nerve injury (68% and 75%), whereas systemic complications such as cardiovascular collapse (16% and 22%) or death (14% and 22%) were less often discussed. In children, general anesthesia was preferred (90% and 86%), whereas adults received local (49% and 41%) or general anesthesia (47% and 43%). Preprocedural coagulation testing and anticoagulation strategies showed marked heterogeneity, especially for venous malformations. Conclusions: This survey demonstrates substantial variability in SFVM management, particularly regarding sclerosant selection, anesthesia, coagulation, periprocedural care, and risk communication, and identifies areas where future prospective and collaborative research will be needed before evidence-based recommendations can be developed.