Wake-up Stroke and Stroke within the Therapeutic Window for Thrombolysis Have Similar Clinical Severity, Imaging Characteristics, and Outcome.

BACKGROUND Wake-up stroke (WUS) represents 25% of all ischemic strokes. There is conflicting evidence concerning clinical severity, imaging characteristics, and outcome when WUS is compared with stroke of known time of onset. Our aim was to compare WUS patients with patients with ischemic stroke within the therapeutic window (STW) for thrombolysis. METHODS This is a retrospective hospital-based study of all consecutive patients hospitalized for acute ischemic stroke during 2013. Patients with STW, WUS, and WUS with computed tomography (CT)  at 3 hours or less after awakening (WUS≤3h) were selected for the study. The methods used include a review of clinical records, an independent quantification of early signs of ischemia on admission CT scan, and determination of functional outcome on follow-up. RESULTS Of 554 patients evaluated, 190 had STW, 113 had WUS (20.4%), and 25 had WUS≤3h. Among all WUS patients, 33.6% did not have any other formal contraindication for thrombolysis besides undetermined time of onset. WUS patients had demographic characteristics, vascular risk factors, and clinical severity similar to STW patients. Mild or absent early signs of ischemia on admission CT in WUS≤3h patients were similar to those in STW patients when adjusted for clinical severity (odds ratio [OR] = .50, 95% confidence interval [CI]=.17-1.47). Favorable prognosis in WUS≤3h was similar to STW when adjusted for age, clinical severity, and thrombolysis (OR = .53, 95% CI=.09-3.14). CONCLUSIONS This study strengthens the evidence that clinical and early imaging characteristics of WUS patients are similar to those of patients with stroke who are eligible for thrombolysis based on the time window criteria, and patients with WUS do not have a worse short outcome.