Abstract WP166: Endovascular Stroke Therapy For Posterior Circulation Ischemic Stroke Has Diminishing Benefits With Number Of Retrieval Attempts

Abstract

Introduction: The relationship between pass number during endovascular therapy (EVT) and outcomes in anterior circulation large vessel occlusion (LVO) acute ischemic stroke (AIS) has been well studied. However, the association between number of thrombectomy attempts and outcomes for patients with posterior circulation LVO remains undetermined. Methods: From our prospective multi-institutional registry including 4 comprehensive stroke centers in the Houston area, we identified consecutive LVO AIS patients who underwent EVT (01/2018-06/2021). The number of thrombectomy passes and per-pass reperfusion grades (TICI) were recorded at time of the EVT procedure. The primary outcome was the effect of number of passes on functional independence (modified Rankin Scale 0-2) at 90 days. Secondary outcomes included likelihood of attaining substantial reperfusion (TICI ≥2b). Results: Among 894 LVO AIS patients who underwent EVT, median age was 68 [IQR 58-78], 49% were female, and median NIHSS was 16 [IQR 11-21]. Of this cohort, 86 had posterior circulation LVO including 65 with basilar artery occlusion and 9 vertebral artery. The diminishing benefit on reperfusion and functional outcome after additional EVT passes was similar for anterior and posterior circulation AIS (Figure 1). Among patients with posterior circulation LVO, successful reperfusion with fewer passes was associated with greater likelihood of good outcomes (41.9% vs 6.7% mRS 0-2 with 1-2 vs ≥3, p=0.012). The likelihood of good outcomes with 1-2 passes for patients with posterior circulation LVO was comparable to patients with anterior circulation LVO (41.9% vs 40.2%, p=0.164). Conclusions: Similar to patients with anterior circulation LVO, patients with posterior circulation LVO undergoing EVT are more likely to achieve functional independence with successful reperfusion in fewer EVT attempts. Overall clinical outcomes are significantly better with fewer passes regardless of occlusion location.