CLINICAL STUDY Treatment Outcomes of Embolization for Peripheral Arteriovenous Malformations Fr  ed  erique C.M. Bouwman, MD, Sanne M.B.I. Botden, MD, PhD, Bas H. Verhoeven, MD, PhD, Leo J. Schultze Kool, MD, PhD, Carine J.M. van der Vleuten, MD, PhD, Ivo de Blaauw, MD, PhD, and Willemijn M. Klein, MD, PhD ABSTRACT Purpose: To evaluate treatment outcomes of embolization for peripheral arteriovenous malformations (AVMs) in a tertiary referral center where ethanol is the primary agent of choice. Methods: A retrospective study was performed of 93 patients (median age, 31 years; range, 2–66 years) with peripheral AVMs treated with embolization (n ¼ 442; median, 2 per patient; range, 1–82) between January 2010 and July 2016. Ethanol was used in most cases (n ¼ 428; 97%). AVMs were classified as type I (n ¼ 3), type II (n ¼ 57), type IIIa (n ¼ 5), type IIIb (n ¼ 15), and type IV (n ¼ 13) according to the Yakes classification system. Effectiveness of embolization was based on AVM devascularization on angiography: 100% (total), 90%–99% (near-total), 70%–90% (substantial), 30%–70% (partial), and 0%–30% (failure). Complications were graded ac- cording to the Society of Interventional Radiology classification. Results: In 69% of patients, 70%–100% devascularization was achieved. Total and near-total occlusion of the nidus were more often achieved in AVMs of types I and IIIa (both 100%) than in AVMs of types II, IIIb, and IV (56%, 67%, and 39%, respectively; P ¼ .019). A total of 109 complications were identified: 101 minor (22.9%) and 8 major (1.8%). Major complications included wounds (n ¼ 5), false aneurysm (n ¼ 1), finger contracture (n ¼ 1), and severe pain (n ¼ 1) requiring therapy. The patient complication risk was significantly affected by the number of procedures (relative risk ¼ 2.0; P < .001). Age, AVM location, and angioarchitecture type did not significantly affect complication risk. Conclusions: AVM embolization resulted in 70%–100% devascularization in 69% of patients, with few major complications. This study indicates that the type of AVM angioarchitecture affects the number of procedures needed and the achievability of AVM devascularization. ABBREVIATIONS AVM ¼ arteriovenous malformation, CVM ¼ congenital vascular malformation Arteriovenous malformations (AVMs) are classified in the group of congenital vascular malformations (CVMs) and have an incidence of 4–24/10,000 (1,2). AVMs grow steadily as the body matures and do not show spontaneous involution. Sudden expansion of these high-flow lesions might be triggered by infection, hormonal changes, or trauma (3). Most symptomatic patients are treated with embolization of the AVM, with the aim of complete oc- clusion of the nidus (4). Although ethanol is considered the most potent agent for embolization (5), other agents such as Onyx (ethylene-vinyl alcohol polymer) have been used (6–8). This is probably because ethanol has been associated with frequent and se- vere complications (9–15). As a result, larger studies (including >30 patients) about ethanol embolization of AVMs are scant (16–19). Regarding influencing factors, AVM extent and angioarchitecture type were retrospectively identified as significant predictive factors for outcome (16,20). From the Departments of Radiology and Nuclear Medicine (F.C.M.B., L.J.S.K., W.M.K.) and Dermatology (C.J.M.V.), Radboudumc, P.O. Box 9101, 6500 HB, Nijmegen, Netherlands; and Department of Surgery (F.C.M.B., S.M.B.I.B., B. H.V., I.D.), Division of Pediatric Surgery, Radboudumc-Amalia Children’s Hospital, Nijmegen, Netherlands. Received July 1, 2019; final revision received November 27, 2019; accepted December 17, 2019. Address correspon- dence to F.C.M.B.; E-mail: Frederique.Bouwman@radboudumc.nl None of the authors have identified a conflict of interest. © SIR, 2020 J Vasc Interv Radiol 2020; ▪:1–9 https://doi.org/10.1016/j.jvir.2019.12.811