Comparison of two aspirin doses on ischemic stroke in post-myocardial infarction patients in the warfarin (Coumadin) Aspirin Reinfarction Study (CARS)

The Coumadin Aspirin Reinfarction Study demonstrated that combination treat ment with fixed dose warfarin (I or 3 mg) + aspirin 80 mg was not superior to aspirin 160 mg alone after myocardial infarction for reducing nonfatal r einfarction, nonfatal stroke, and cardiovascular death. In this analysis, w e examined the importance of aspirin dose in the protection against the sec ondary end point of ischemic stroke. The comparison arms for this analysis were warfarin I mg + aspirin 80 mg versus aspirin 160 mg. In the Coumadin A spirin Reinfarction Study, 2,028 patients were randomized to aspirin 80 mg plus warfarin 1 mg, and 3,393 were randomized to aspirin 160 mg alone. A pr edictive model for ischemic stroke was developed using the Cox proportional -hazards model. A reduced Cox proportional-hazards model was developed to t est for the effect of aspirin dose on ischemic stroke in predefined subgrou ps. The incidence of ischemic stroke was lower in patients treated with asp irin 160 mg than in patients treated with aspirin 80 mg + warfarin I mg (0. 6% vs 1.1%; p = 0.0534). Age, previous stroke or transient ischemic attack, and aspirin dose were independent predictors of ischemic stroke. In additi on, the highest risk patients, those with Q-wave myocardial infarction and male patients, appeared to receive greater benefit from aspirin It 60 mg th an from aspirin 80 mg + warfarin I mg. The results of this secondary analys is suggest that aspirin 160 mg is more effective than aspirin 80 mg + warfa rin 1 mg in preventing ischemic stroke in post-myocardial infarction patien ts. (C) 2001 by Excerpta Medica, Inc.