Abstract 1122‐000093: Association of Pre‐Mechanical Thrombectomy Collateral Scores with Functional‐Outcome in Short Versus Extended Window for Thrombectomy

Introduction : We aim to determine the utility of pre‐mechanical‐thrombectomy (MT) collateral scores in the short (<6 hours from onset) versus extended (6‐24 hours from onset) window for MT with respect to a good functional‐outcome. Methods : We performed a retrospective chart review of patients who underwent MT for anterior circulation LVO at a comprehensive stroke center from 7/2014 to 12/2020. A board‐certified neuroradiologist, who was blinded to the clinical‐outcomes, used collateral grading scales of Miteff (ordinal), Mass (ordinal), and modified‐Tan (dichotomous) to designate collateral scores on the pre‐MT CT Angiogram. The patients were divided into short (<6 hours from onset) versus extended (6‐24 hours from onset) groups depending on their timing of presentation to the emergency department. A binary logistic regression analysis was performed, controlling for age, sex, NIHSS, ASPECTS≥6, TICI score≥2b, recanalization time, mean arterial pressure, blood glucose, location of occlusion, atrial fibrillation, LDL, hemoglobin‐A1C, and administration of intravenous‐alteplase, with the pre‐MT collateral grading scores as predictors. The primary outcome was a good functional‐outcome (3‐month mRS≤2) Results : 162 patients met our inclusion criteria for patients who presented in the short window. The pre‐MT scales of Mass (OR, 0.35; 95%CI, 0.16‐0.78; P 0.01) and modified‐Tan (OR, 0.35; 95%CI, 0.16‐0.78; P 0.01) were associated with a good functional‐outcome, unlike the Miteff scale (OR, 0.46; 95% CI, 0.18‐1.18; P 0.103). 58 patients met our inclusion criteria for patients who presented in the extended window. The pre‐MT scales of Mass (OR, 0.75; 95% CI, 0.23‐2.48; P 0.63), Miteff scale (OR, 0.78; 95%CI, 0.17‐3.64; P 0.746) and modified‐Tan (OR, 1.14; 95%CI, 0.1‐12.98; P 0.918) were not associated with a good functional‐outcome. Conclusions : Our study demonstrates that good collateral grades on Mass and modified‐Tan scales are associated with a good functional outcome for patients who present to the ED in the short window for MT. We did not find an association of any pre‐MT collateral scores with a good functional‐outcome for patients presenting in the extended window for MT.