Risk Assessment in Flow-Diverter Implantation of Vertebrobasilar Dolichoectasia: A Novel Three-Subtype Classification

BACKGROUND AND PURPOSE: Vertebrobasilar dolichoectasia is a rare cerebrovascular disorder with a poor natural history. Flow diverters have emerged as a treatment option, but clinical outcomes remain heterogeneous and predictors of procedural risk are lacking. This study aimed to identify predictors of perioperative outcomes and develop an imaging-based classification for risk stratification. MATERIALS AND METHODS: We retrospectively analyzed 59 consecutive patients with unruptured vertebrobasilar dolichoectasia who underwent flow-diverter implantation between 2018 and 2023. Clinical and angiographic follow-up was performed at 6 and 12 months and annually thereafter. Clinical outcomes were assessed with the mRS, and angiographic outcomes by occlusion status. Logistic regression identified predictors of perioperative unfavorable outcomes. Lesions were characterized by the location of maximal dilation relative to the AICA origin and the presence of intraluminal thrombus. RESULTS: = .02). Angiographic occlusion rates did not differ among subtypes. CONCLUSIONS: We propose a three-subtype classification for vertebrobasilar dolichoectasia based on intraluminal thrombus and lesion location relative to the AICA that may help stratify procedural risk with flow-diverter implantation. Type C lesions may represent relatively more suitable candidates for treatment, whereas Types A and B may carry higher risk and should prompt cautious patient selection. Prospective multicenter validation is warranted.