Aspirin versus coumadin.

Aspirin Versus Coumadin A study in Circulation by Meijer et all describes an angiographic study in patients with successful thrombolysis and open infarctrelated vessel within 48 hours who underwent repeat coronary angiography at 3 months after having been treated with either 325 mg aspirin or matching placebo or open-label coumadin (INR 2.8-4.0). The authors conclude that when heparin is given in the acute phase of myocardial infarction, this should be followed by aspirin treatment because aspirin reduces recurrent myocardial infarction and the need for revascularization and tends to reduce angiographic reocclusion. There are several important limitations inconsistent with respect to this conclusion that need to be highlighted. Since a comparison to placebo is outdated, the main comparison of interest is between aspirin and coumadin, which are the two effective strategies for secondary prophylaxis in patients with myocardial infarction. With respect to this comparison, it is important to note that the study was nonrandomized and was stopped prematurely. Angiographic comparison did not reveal a difference in reocclusion at 3 months; however, there was an insignificant increase in reinfarction, revascularization, and death, which as a combined end point resulted in 93% event-free survival in aspirin group versus 82% in the coumadin arm (P=.03), which is the most important comparison leading to the authors' conclusion that aspirin is better than coumadin. However, the total number of patients having hard end points (death and reinfarction) contributing to this difference is small (four in the aspirin group and nine in the coumadin group); given the open-label comparison between these two arms, interpretation of softer end points such as revascularization is more difficult. Furthermore, five of the seven reinfarctions in the coumadin group occurred during heparin infusion before coumadin therapy was instituted. This did not occur in patients who ultimately received aspirin while they were receiving IV heparin, suggesting misfortune for those randomized to coumadin arm but not necessarily a difference in treatment effect between coumadin and aspirin. Indeed, if these five reinfarctions are discounted, no significant difference exists in clinical end points between aspirin and coumadin. In summary, I believe this study shows benefit from the use of aspirin compared with placebo. Unfortunately, this study does not adequately compare the two most frequently used modalities of secondary prophylaxis, aspirin and coumadin, because of openlabel design, premature discontinuation of the study, and small number of patients. Given these considerations, the authors' conclusions should be interpreted with caution.