Alberta Stroke Program Early Computed Tomography Score to Select Patients for Endovascular Treatment

Background and Purpose—The Interventional Management of Stroke (IMS)-III trial randomized patients with acute ischemic stroke to intravenous tissue-type plasminogen activator (tPA) plus endovascular therapy versus intravenous tPA therapy alone within 3 hours from symptom onset. A predefined secondary hypothesis was that subjects with significant early ischemic change on the baseline scan would not respond to endovascular therapy. Methods—The primary outcome was 90-day modified Rankin Scale score 0 to 2. The baseline and follow-up computed tomographic (CT) scan images were reviewed centrally and blinded to any clinical information. We assessed whether the baseline Alberta Stroke Program Early CT Score (ASPECTS) predicted outcome and interacted with study treatment. We analyzed subgroups defined by time from onset to intravenous tPA initiation and baseline occlusion status at a prespecified α=0.01. Results—Baseline demographic and clinical characteristics of 656 randomized patients were similar between subj...