Second and third interim analyses will be performed after 350 and 500 patients have been enrolled. If the sample size is adjusted at the first interim analysis, the second and third analyses will be performed after 60% and 75%, respectively, of the required sample size is enrolled. For these analyses, the study statistician will be unblinded to treatment allocation and the proportion of patients suffering adjudication confirmed major hemorrhage will be compared between the two groups. If there is a treatment advantage as measured by a two-tailed Chi-square or Fisher's exact test with a P value of less than 0.001 the statistician will recommend to the study Steering Committee that the study be stopped. Any other result will result in a recommendation to continue this study.