The ultimate objective of this trial is to improve upon the current standard therapy (aspirin) for the prevention of secondary vascular events in post Acute Coronary Syndrome patients. Aspirin decreases the ability of platelets to stick together and reduces the risk of a second serious heart attack by up to 39%. However, aspirin is a relatively weak anti-platelet drug. Xubix is also an anti-platelet drug that may prove more effective than aspirin given alone or when combined with aspirin in reducing the risk of a second heart attack. The primary endpoints for this study are death, myocardial infarction or reinfarction, and severe recurrent ischemia.