Approaching the Boundaries of Endovascular Treatment in Acute Ischemic Stroke : Multicenter Experience with Mechanical Thrombectomy in Vertebrobasilar Artery Branch Occlusions.

PURPOSE: Little is known about catheter-based endovascular treatment of vertebrobasilar artery branch occlusion (VEBABO) in acute ischemic stroke (AIS). Nonetheless, the experience of mechanical thrombectomy (MT) in distal small sized arteries of the anterior circulation seems promising in AIS. In this multicenter study, we report the feasibility, efficacy and safety of MT in VEBABO. METHODS: Retrospective analysis of consecutive AIS patients treated with MT due to VEBABO including posterior and anterior inferior cerebellar artery (PICA, AICA) and superior cerebellar artery (SCA) occlusions at seven tertiary care centers between January 2013 and May 2020. Baseline demographics and angiographic outcomes including recanalization success of the affected cerebellar arteries and procedural complications were recorded. Clinical outcomes were evaluated by the modified Rankin scale (mRS) at discharge and 90 days. RESULTS: Out of 668 endovascularly treated posterior circulation strokes we identified 16 (0.02%) cases with MT for VEBABO. Most frequently, MT of the SCA was done (13/16, 81%). Most VEBABOs occurred after MT of initial basilar/posterior cerebral artery occlusion (9/16, 56%). In 10/16 (63%) procedures, the affected VEBABO was successfully recanalized. Out of four patients three (75%) with isolated VEBABO had benefited from endovascular therapy. Subarachnoid hemorrhage was observed in 3/16 (19%) procedures. The rate of favorable outcome (mRS ≤2) was 40% at discharge and 47% at 90-day follow-up. Mortality was 13% (2/15). CONCLUSION: The use of MT for VEBABO is rare but appears to be feasible and effective; however, the comparatively high rate of procedure-related hemorrhage highlights that the indications for MT in these occlusion sites should be carefully weighed up.