Lack of effect of aspirin in asymptomatic patients with carotid bruits and substantial carotid narrowing. The Asymptomatic Cervical Bruit Study Group.
Côté R., Battista RN., Abrahamowicz M., Langlois Y., Bourque F., Mackey A.
OBJECTIVE: To determine the effectiveness of aspirin in preventing ischemic events in patients with asymptomatic carotid stenosis. DESIGN: Double-blind, placebo-controlled trial. SETTING: University-affiliated hospitals. PATIENTS: 372 neurologically asymptomatic patients with carotid stenosis of 50% or more in at least one artery as determined by luminal diameter reduction on duplex ultrasonography. INTERVENTION: Patients 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 recipients. OUTCOME MEASURES: Patients were scheduled for a clinical examination every 6 months for assessment of the occurrence of any clinical event in the composite end point, which consisted of transient ischemic attack, stroke, myocardial infarction, unstable angina, or death. RESULTS: At baseline, the 188 patients receiving aspirin and the 184 patients receiving placebo had similar demographic, ultrasonographic, and laboratory characteristics. The median duration of follow-up was 2.3 years. 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). CONCLUSION: Aspirin did not have a significant long-term protective effect in asymptomatic patients with high-grade (> or = 50%) carotid stenosis.