A randomized trial of aspirin on the risk of embolic events in patients with infective endocarditis

J Am Coll Cardiol. 2003 Sep 3;42(5):775-80. doi: 10.1016/s0735-1097(03)00829-5.


Objectives: This study examined the effect of aspirin on the risk of embolic events in infective endocarditis (IE).

Background: Embolism is a major complication of IE, and studies in animal models have shown that platelet inhibition with aspirin can lead to more rapid vegetation resolution and a lower rate of embolic events.

Methods: We conducted a randomized, double-blinded, placebo-controlled trial of aspirin treatment (325 mg/day) for four weeks in patients with IE to test the hypothesis that the addition of aspirin would reduce the incidence of clinical systemic embolic events. Patients with perivalvular abscess were excluded. Serial cerebral computed tomograms and transesophageal echocardiograms were obtained in a subset of patients.

Results: During the four-year study period, 115 patients were enrolled: 60 assigned to aspirin and 55 assigned to placebo. Embolic events occurred in 17 patients (28.3%) on aspirin and 11 patients (20.0%) on placebo, with an odds ratio (OR) of 1.62 (95% confidence interval [CI] 0.68 to 3.86, p = 0.29). There was a trend toward a higher incidence of bleeding in the patients taking aspirin versus placebo (OR 1.92, 95% CI 0.76 to 4.86, p = 0.075). Development of new intracranial lesions was similar in both groups. Aspirin had no effect on vegetation resolution and valvular dysfunction.

Conclusions: In endocarditis patients already receiving antibiotic treatment, the addition of aspirin does not appear to reduce the risk of embolic events and is likely associated with an increased risk of bleeding. Aspirin is not indicated in the early management of patients with IE.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Anti-Bacterial Agents / therapeutic use
  • Aspirin / adverse effects
  • Aspirin / therapeutic use*
  • Double-Blind Method
  • Drug Therapy, Combination
  • Echocardiography, Transesophageal
  • Embolism / diagnosis
  • Embolism / epidemiology
  • Embolism / etiology*
  • Embolism / prevention & control*
  • Endocarditis, Bacterial / complications*
  • Endocarditis, Bacterial / diagnosis
  • Endocarditis, Bacterial / drug therapy*
  • Female
  • Follow-Up Studies
  • Hemorrhage / chemically induced
  • Hemorrhage / epidemiology
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Odds Ratio
  • Platelet Aggregation Inhibitors / adverse effects
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Proportional Hazards Models
  • Risk Factors
  • Severity of Illness Index
  • Single-Blind Method
  • Tomography, X-Ray Computed
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Platelet Aggregation Inhibitors
  • Aspirin