Comparison of warfarin and aspirin for symptomatic intracranial arterial stenosis

BACKGROUND: Atherosclerotic intracranial arterial stenosis is an important cau se of stroke. Warfarin is commonly used in preference to aspirin for this disord er, but these therapies have not been compared in a randomized trial. METHODS: W e randomly assigned patients with transient ischemic attack or stroke caused by angiographically verified 50 to 99 percent stenosis of a major intracranial arte ry to receive warfarin (target international normalized ratio, 2.0 to 3.0) or as pirin (1300 mg per day) in a double-blind, multicenter clinical trial. The prim ary end point was ischemic stroke, brain hemorrhage, or death from vascular caus es other than stroke. RESULTS: After 569 patients had undergone randomization, e nrollment was stopped because of concerns about the safety of the patients who h ad been assigned to receive warfarin. During a mean follow-up period of 1.8 yea rs, adverse events in the two groups included death (4.3 percent in the aspirin group vs. 9.7 percent in the warfarin group; hazard ratio for aspirin relative t o warfarin, 0.46; 95 percent confidence interval, 0.23 to 0.90; P=0.02), major h emorrhage (3.2 percent vs. 8.3 percent, respectively; hazard ratio, 0.39; 95 per cent confidence interval, 0.18 to 0.84; P=0.01), and myocardial infarction or su dden death (2.9 percent vs. 7.3 percent, respectively; hazard ratio, 0.40; 95 pe rcent confidence interval, 0.18 to 0.91; P=0.02). The rate of death from vascula r causes was 3.2 percent in the aspirin group and 5.9 percent in the warfarin gr oup (P=0.16); the rate of death from nonvascular causes was 1.1 percent and 3.8 percent, respectively (P=0.05). The primary end point occurred in 22.1 percent o f the patients in the aspirin group and 21.8 percent of those in the warfarin gr oup (hazard ratio, 1.04; 95 percent confidence interval, 0.73 to 1.48; P=0.83). CONCLUSIONS: Warfarin was associated with significantly higher rates of adverse events and provided no benefit over aspirin in this trial. Aspirin should be use d in preference to warfarin for patients with intracranial arterial stenosis.