Abstract TP145: Mechanical Thrombectomy Beyond 24 Hours

Abstract

Background: Multiple randomized controlled trials have shown that mechanical thrombectomy (MT) is superior to medical therapy. However, no robust evidence is available to assess the effectiveness of MT beyond the 24-hour window. In this study, we aimed to determine the safety and efficacy of MT in patients undergoing MT for stroke beyond 24 hours from last known normal (LKN). Methods: Retrospective review of a prospectively collected database for subjects who met extended window trial criteria, but underwent MT beyond 24 hours. Recorded variables included age, sex, NIHSS at baseline and at discharge, risk factors, level of occlusion, access site, thrombectomy method. Safety and efficacy outcomes included symptomatic intracerebral hemorrhage (sICH), procedural complications, number of passes, successful recanalization (TICI 2b-3), Δ NIHSS (baseline-discharge), favorable outcomes (mRS 0-2) at 90 days. Results: A total of 39 patients were included with a median age of 69 (IQR 61.5, 73.5); 54% were females. Hypertension was the most frequent risk factor in 76% of patients; 23 % of patients were smokers. Half of the patients had M1 occlusion (48.7%). Median preprocedural NIHSS was 11 (IQR 7.0, 19.5). Successful revascularization was achieved in 87%; median number of passes was 2 (IQR 1.0,3.0). Median ΔNIHSS was 3.0 (IQR -1.5, 8.0). Favorable outcome was achieved in 49% (95% CI: 34%-64%), and 95% were free of complications. A total of 3 patients (7.7%) had sICH. In an exploratory analysis, posterior circulation occlusion was associated with higher risk of poor mRS at 90 days (OR: 14.7, p = 0.016). Additionally, favorable discharge facility (home, home health, or rehab) was associated with a much lower risk of poor mRS at 90 days (OR: 0.11, p = 0.004). Conclusions: Our single center study of MT beyond 24 hours showed comparable clinical outcomes and safety profile to large MT trials within 24 hours, especially in anterior circulation occlusions. Posterior circulation occlusions were associated with worse outcomes, which warrants further investigation.