Flow Diversion for Treatment of Partially Thrombosed Aneurysms: A Multicenter Cohort

Abstract Objective Partially thrombosed intracranial aneurysms (PTIA) represent a unique subset of intracranial aneurysms with an ill-defined natural history, posing challenges to standard management strategies. This study aims to assess the efficacy of flow diversion in treatment of this pathology. Methods A retrospective review of patients with flow-diverted PTIAs at 6 cerebrovascular centers was performed. Clinical and radiographic data was collected from the medical records, with primary outcome of aneurysmal occlusion and secondary outcomes of clinical status and complications. Results Fifty patients with 51 PTIAs treated with flow diversion were included. Median age was 56.5 years. Thirty-three (64.7%) aneurysms were saccular and 16 (31.4%) were fusiform/dolichoectatic. The most common location was the internal carotid artery (54.9%) followed by the vertebral and basilar arteries (17.7% and 17.7%, respectively). Last imaging follow-up was performed at a median of 25.1 (IQR 12.8 – 43) months. Complete occlusion at last radiographic follow-up was achieved in 37 (77.1%) aneurysms. Pre-treatment aneurysm thrombosis of >50% was associated with a significantly lower rate of complete aneurysm occlusion (58.8 vs 87.1%, p = 0.026) with a trend toward better functional outcome (modified Rankin Scale Conclusions Flow diversion treatment of PTIA has adequate efficacy along with a reasonable safety profile. Aneurysms harboring large amounts of pre-treatment thrombus were associated with lower rates of complete occlusion.