Warfarin and aspirin versus aspirin alone in patients with acute myocardial infarction: a pilot study

The benefits of anticoagulant therapy and antiplatelet agents in secondary prevention of myocardial infarction (MI) are well known. Administration of combined warfarin and aspirin (ASA) has not been well studied. The objective of this study was to compare the effect of coadministration of warfarin and ASA with administration of ASA alone on outcome of patients after MI. One hundred forty age- and sex-matched survivors of MI were randomized to receive either 100 mg/day ASA plus enough warfarin to reach a target: international normalized ratio of 2.5 (range: 2-3) (group A, n = 70), or only 100 mg/day ASA (group B, n = 70). The patients were examined for several variables including development of hemorrhage, reinfarction, and rehospitalization for 1 year post MI. Of the variables studied, minor hemorrhagic episodes were observed significantly (p = 0.002) more in group A than in group B patients. Rehospitalization and reinfarction rates, although occurring with lower frequencies in group A than in group B, did not reach the statistical significance level. In postmyocardial infarction patients, warfarin plus ASA did not provide a clinical benefit beyond that achievable with aspirin monotherapy, and for the observed markedly higher incidence of minor hemorrhage in combination therapy, antiplatelet therapy alone seems to be a more reasonable approach.