Interpretation:

Among patients who have sustained an acute MI, warfarin, in combination with aspirin or given alone, was superior to aspirin alone in reducing the incidence of death / recurrent MI/ and thromboembolic stroke. This came at the cost of an approximately 0.5% higher rate of bleeding. Despite these therapies, patients with a recent myocardial infarction continue to be at an increased risk of additional cardiovascular events. An important consideration is that in the United States, primary PCI with stenting is performed in 15 to 20 percent of patients who present with ST-segment elevation myocardial infarction, and an additional 20 - 40 % undergo PCI within the subsequent six weeks. Thus over 50% or more individuals will receive clopidogrel for at least four weeks and up to nine months after myocardial infarction. There is currently no data on the safety of the combination of aspirin, clopidogrel and warfarin together and previous trials have conclusively shown that warfarin is not effective in preventing stent thrombosis. Thus, for more than 50% of patients in the US, an aspirin and warfarin combination may not be applicable. A future trial comparing aspirin plus clopidogrel versus aspirin plus warfarin may be more useful to determine optimal antiplatelet / antithrombotic secondary prevention therapy.