Berger JS et al. (2008) Initial aspirin dose and outcome among ST-elevation myocardial infarction patients treated with fibrinolytic therapy. Circulation 117: 192–199

Immediate administration of aspirin after ST-segment-elevation myocardial infarction (STEMI) reduces the risk of vascular events, but the optimum dose in this setting is unknown. Berger et al. retrospectively analyzed data from two trials of fibrinolytic therapy in STEMI to determine the effect of high-dose versus low-dose aspirin on cardiovascular outcome and bleeding events.

From 1990 to 1997, the GUSTO I and GUSTO III trials enrolled patients with STEMI <6 h after symptom onset. Patients were treated in the acute setting with a single dose of aspirin in the range 126–162 mg or 163–330 mg ('162 mg group' and '325 mg group', respectively) at the discretion of the treating physician.

This analysis included a total of 48,422 patients, of whom 11,828 (24.4%) were in the 325 mg group and 36,594 (75.6%) were in the 162 mg group. After adjustment for baseline, treatment and procedural characteristics, there were no significant differences between the 325 mg and the 162 mg groups in the composite end point of mortality, myocardial infarction or stroke at 24 h (odds ratio [OR] 1.05, 95% CI 0.91–1.21) or at 7 days (OR 1.00, 95% CI 0.91–1.10), or in mortality at 30 days (OR 0.99, 95% CI 0.87–1.12). The 325 mg dose was independently associated with a significantly increased risk of in-hospital major or moderate bleeding compared with the 162 mg dose (OR 1.14, 95% CI 1.05–1.24; P<0.003).

The authors conclude that an initial aspirin dose of 162 mg may be as effective as, and possibly safer than, a 325 mg dose in patients with STEMI.