Platelet Inhibitory Effect of Clopidogrel in Patients Treated With Omeprazole, Pantoprazole, or Famotidine

Inclusion Criteria: 1. Subject is at least 18 years old. 2. Subject is willing to comply with pre-specified follow-up evaluation and can be contacted by telephone. 3. Use of Clopidogrel (\>=75mg) and Aspirin(\>=75mg) for at least 1 month. Exclusion Criteria: 1. Known allergy to PPI of H2 blockers 2. Known thrombocytopenia or thrombocytopathia 3. Subject is currently enrolled in another investigational study of a new drug, biologic or device at the time of study screening. NOTE: Subjects who are participating in the long term follow-up phase of a previously investigational and now FDA-approved product are not excluded by this criterion. 4. Subject with symptomatic heart failure of LVEF ≤ 25% 5. Acute myocardial infarction within the past 30 days. 6. No acute inflammatory event during the past month (e.g. infection, autoimmune or acute coronary event) 7. Concurrent medical condition with a life expectancy of less than 12 months. 8. Known severe renal failure (serum creatinine level \>2.5 mg/dl). 9. History of bleeding diathesis or coagulopathy or inability or unwillingness to receive blood transfusions. 10. Evidence of active gastrointestinal bleeding or a history of such bleeding that is not known to have been treated and proven to have resolved. 11. History of hepatitis (viral, ischemic or chemically-induced); clinical jaundice, history of cirrhosis. 12. Patient treated with anticoagulant medication (Coumadin, LMWH)