Abstract WP258: Predicting Stroke Outcomes Using Cerebrovascular Collateral Circulation in Patients with Large Ischemic Core

Introduction: Endovascular Thrombectomy (EVT) is highly effective for the treatment of acute ischemic stroke (AIS), but patients with large core infarcts (LC-AIS), defined by low ASPECTS or large infarct volume, were initially excluded from EVT trials. Emerging evidence suggests that select LC-AIS patients may benefit from EVT. Collateral circulation robustness is a key factor in preserving brain perfusion and limiting infarct growth. We hypothesize that collateral status significantly influences outcomes in LC-AIS patients undergoing EVT. Methods: We retrospectively analyzed LC-AIS patients who underwent EVT between 2019 and 2024, using a prospectively collected database at our comprehensive stroke center. Quantitative collateral index (qCI) was calculated from the initial computed tomography angiography (CTA) using our validated and fully automated machine-learning algorithm. The primary outcome was hospital disposition. Results: Patients with ASPECTS