Early stroke risk after transient ischemic attack among individuals with symptomatic intracranial artery stenosis.

BACKGROUND Little is known about short-term vascular risk after transient ischemic attack (TIA) caused by intracranial atherosclerosis. OBJECTIVES To quantify the early risk of ischemic stroke in the territory of a stenotic intracranial artery after TIA and to identify clinical and imaging features associated with increased risk of stroke in the territory among patients with TIA. DESIGN Cohort study. SETTING Academic research. Patients The Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) study enrolled patients having TIA or nondisabling stroke within the preceding 3 months and demonstrating corresponding 50% to 99% stenosis of a major intracranial artery on angiography. MAIN OUTCOME MEASURES We calculated the cumulative risk of stroke in the territory of the symptomatic artery during the first 90 days after randomization among patients having TIA alone as a qualifying event compared with patients having stroke alone. We assessed selected factors for association with stroke among patients having TIA as the qualifying event. RESULTS The 90-day risk of ischemic stroke in the arterial territory was 6.9% (95% confidence interval, 4.2%-11.2%) after TIA compared with 4.7% (95% confidence interval, 2.7%-8.4%) after stroke (P =.32). Among patients having TIA alone as the qualifying event, 60.0% (15 of 25) of all strokes in the arterial territory occurred in the first 90 days compared with 34.4% (11 of 32) among patients having stroke alone as the qualifying event (P =.05). Among subjects with TIA, the presence of cerebral infarct on baseline neuroimaging was the only statistically significant predictor of higher risk of early stroke (hazard ratio, 4.7; 95% confidence interval, 1.4-15.5; P =.006). CONCLUSIONS Among individuals having intracranial atherosclerotic disease with TIA, most subsequent strokes in the territory of a stenotic intracranial artery occur early (ie, < or =90 days). Prompt management of TIA in patients having intracranial stenosis, particularly those demonstrating cerebral infarction on brain imaging, is indicated.