Does Aspirin Prevent Emboli in Infective Endocarditis?

Abstract

Methods: A multicenter, randomized, double-blind, placebo controlled trial was conducted in 19 centers—18 in Canada and one in the United States. Of the planned study size of 368 patients (based on power considerations), 115 were ultimately randomized. Enrolled patients met a modified Duke criteria definition for diagnosis of endocarditis and were aged between 16 and 80 years. Patients were excluded if a paravalvular abscess was seen by echocardiography, if they were expected to have surgery within a week, if they already had a current or evolving central nervous system vascular event, or if they had a contraindication to aspirin, such as an episode of gastrointestinal bleeding or peptic ulcer disease in the prior 12 months, allergy to aspirin, or a bleeding diathesis. Patients already taking aspirin for other reasons also were excluded. Patients were randomly assigned to receive 325 mg daily of aspirin or placebo for 4 weeks. Anticoagulation for prosthetic valves was continued. Patients were followed clinically, and when clinically indicated, were studied radiologically. Additional studies, such as computed tomograms of the head at baseline and after therapy, were encouraged but not required. Patients also were followed by transthoracic echocardiography (transesophageal studies were encouraged) to assess changes in vegetations. The primary outcome was clinically significant major arterial embolic events. Secondary outcomes included subclinical emboli, death, bleeding, valvular surgery, and echocardiographic progression of vegetations.