Study coordinators recently announced that clopidogrel, a new antiplatelet agent, is significantly better than aspirin at reducing the number of heart attacks, strokes and vascular deaths in at-risk patients. The researchers found that aspirin prevented about one-quarter of these events in study participants, whereas clopidogrel prevented about a third of them. Dr. James T. Willerson and Dr. Edward K. Massin served as co-directors of this study at the Texas Heart Institute at St. Luke's Episcopal Hospital. Dr. Willerson is the medical director, chief of Cardiology, director of Cardiology Research, and co-director of the Cullen Cardiovascular Research Laboratories at Texas Heart Institute at St. Luke's. Dr. Massin is a cardiologist at the Texas Heart Institute and St. Luke's Episcopal Hospital, and medical director at St. Luke's.
Atherosclerotic plaques can cause cracks or fissures in the vessel wall.
Blood platelets aggregate around these fissures and cause the formation of thrombi that can completely block or occlude arteries. This process, atherothrombosis, is the common link which results in ischemic strokes, heart attacks and vascular death. Both aspirin and clopidogrel prevent some platelet aggregation but do so by different mechanisms. For instance, a patient who has had a heart attack is at increased risk not only of a subsequent heart attack, but also of a stroke. This finding is particularly striking since the entire study population had been rigorously selected to exclude those patients with a history of ulcers or gastrointestinal bleeding.