LACK OF EFFECT OF ASPIRIN IN ASYMPTOMATIC PATIENTS WITH CAROTID BRUITS AND SUBSTANTIAL CAROTID NARROWING

Objective: To determine the effectiveness of aspirin in preventing isc hemic events in patients with asymptomatic carotid stenosis. Design: D ouble-blind, placebo-controlled trial. Setting: University-affiliate h ospitals. Patients: 372 neurologically asymptomatic patients with caro tid stenosis of 50% or more in at least one artery as determined by lu minal diameter reduction on duplex ultrasonography. Intervention: Pati ents were randomly assigned to receive either enteric coated aspirin, 325 mg/d, or identically appearing placebo. Duration of therapy was 2. 0 years for the aspirin recipients and 1.9 years for the placebo recip ients.Outcome Measures: Patients were scheduled for a clinical examina tion every 6 months for assessment of the occurrence of any clinical e vent in the composite end point, which consisted of transient ischemic attack, stroke, myocardial infarction, unstable angina, or death. Res ults: At baseline, the 188 patients receiving aspirin and the 184 pati ents receiving placebo had similar demographic, ultrasonographic, and laboratory characteristics. The median duration of follow-up was 2.3 y ears. The annual rate of all ischemic events and death from any cause was 12.3% for the placebo group and 11.0% for the aspirin group (P = 0 .61). The Cox proportional hazards analysis yielded an adjusted hazard ratio (aspirin-placebo) of 0.99 (95% CI, 0.67 to 1.46; P = 0.95). The annual rates for vascular events only were 11% for the placebo group and 10.7% for the aspirin group (P = 0.99). The multivariate analysis yielded a hazard ratio of 1.08 (CI, 0.72 to 1.62; P = 0.71). Conclusio n: Aspirin did not have a significant longterm protective effect in as ymptomatic patients with high-grade (greater than or equal to 50%) car otid stenosis.