Flow-Related Aneurysms in Infratentorial Arteriovenous Malformations: Location-Based Endovascular Treatment of 37 Aneurysms in 25 Cases.

Abstract

The management of flow-related aneurysms (FRAs) associated with infratentorial arteriovenous malformations (AVMs) remains challenging and controversial. In this study, we present our clinical experience with endovascular treatment of these complex lesions. We retrospectively analyzed 25 consecutive patients with ruptured or symptomatic FRAs treated between January 2020 and June 2024. Treatment was tailored to FRA location: proximal FRAs underwent coil embolization to preserve distal flow, while distal FRAs received liquid embolics, often requiring parent artery sacrifice. Clinical outcomes, radiological findings, and treatment approaches were systematically reviewed. Hemorrhage was the most common presenting symptom (19/25, 76.0%), with FRA rupture accounting for 15 cases and AVM nidus bleeding for the remaining 4. Endovascular treatment was performed for 37 FRAs, with proximal aneurysms predominantly managed by coiling (21/22, 95.5%) to preserve distal perfusion, while distal FRAs were primarily treated with liquid embolics (14/15, 93.3%) via feeder sacrifice. Three (12.0%) clinically significant complications occurred, including 2 ischemic events and one case of hydrocephalus. At a mean follow-up of 22.1 months, 24 patients (96.0%) achieved favorable outcomes (modified Rankin Scale ≤2). One patient experienced rebleeding due to enlargement and rupture of an untreated FRA 3 years post-treatment. The natural history of FRAs associated with AVMs remains unpredictable. We recommend aggressive treatment in all cases unless complete AVM occlusion is achieved. Endovascular treatment represents a safe and effective primary therapeutic approach for infratentorial AVM-associated FRAs.