Endovascular treatment for Spetzler–Martin grade IV–V brain arteriovenous malformations: a 26-year single-center cohort study

BACKGROUND: The exclusion treatment of Spetzler-Martin grade (SMG) IV-V brain arteriovenous malformations (bAVMs) remains controversial. This study evaluates the safety and effectiveness of endovascular treatment (EVT) for SMG IV-V bAVMs, either as a standalone strategy or as part of multimodal management. METHODS: A retrospective single-center observational cohort study of consecutive adult patients with SMG IV-V bAVMs treated with EVT between 1998 and 2024 was conducted. Baseline characteristics, procedure-related complications, clinical outcomes, and angiographic follow-up were recorded. Independent risk factors for EVT-related complications were analyzed using binary logistic regression. RESULTS: A total of 73 patients with 73 SMG IV-V bAVMs were included. The median age was 36 (IQR 28-47) years, and 29 (39.7%) bAVMs were ruptured at presentation. Complete angiographic obliteration by EVT alone in intention to cure was achieved in 6/33 patients (18.2%). Overall, complete angiographic obliteration was achieved in 33 patients (45.2%), either by EVT alone or within a multimodal treatment strategy. EVT-related major complications (shift in modified Rankin Scale score of ≥2 or death) occurred in eight patients (11.0%). The presence of a flow-related proximal aneurysm was independently associated with EVT-related complications (OR 4.47; 95% CI 1.18 to 16.98; P=0.028). CONCLUSIONS: In this single-center retrospective series, EVT for SMG IV-V bAVMs was associated with a substantial procedural risk and achieved complete obliteration only in a limited proportion of patients when used as a standalone treatment. Within a multimodal management strategy higher angiographic exclusion rates were observed, although it remained associated with substantial morbidity.