Randomized Study of Aspirin Resistant Patients Undergoing Angioplasty

Inclusion Criteria: Patients with coronary artery disease will be eligible for the study. Inclusion criteria are: Patient is 21 years or older. Patient is scheduled to undergo low-medium risk percutaneous coronary intervention in native coronary vessels. Patient self-reports that he/she has received aspirin ≥ 81 mg at least 4 hours prior to study screening. Patient is defined as aspirin non-responsive based upon results of the VerifyNow™ Aspirin test, defined as an aspirin reaction units (ARU) \> 475. Patient is defined as clopidogrel non-responsive based upon the results of the VerifyNow P2Y12 test, defined as less than 20% inhibition. Patient will be treated with 300- 600 mg of clopidogrel at least two hours before the intervention. All patients will provide written informed consent, and the study protocol will be approved by the IRB of the participating centers. Patient is male, or is a non-pregnant female. Exclusion Criteria: Patient has a known allergic reaction to the study medication. Patient has been diagnosed with a myocardial infarction within the prior 7 days. Patient has unstable angina, defined as dynamic, ischemic ECG changes (ST-segment elevation, ST-segment depression, or T-wave inversion) at rest. Patient has rest pain with left bundle branch block. Note: In a patient with rest pain and abnormal ECG that is believed to be non-acute (i.e., STTW abnormalities secondary to LVH, digoxin, or prior remote infarction), a second electrocardiogram 30 min apart is required to establish that these changes are non-dynamic and not indicative of active ischemia. The target lesion(s) is located in a venous bypass graft. The patient has a chronic occlusion (present for longer than 3 months). The target lesion(s) has visible thrombus (by angiography). The patient has had a suspected aortic dissection. Patient has left ventricular ejection (LVEF) \< 30%. Patient was receiving oral anticoagulation therapy. Patient received any of the following drugs during 7 days prior to enrollment: * any GP IIb/IIIa inhibitor * ticlopidine * dipyridamole * cilostazol (Pletal) Patient has received non-steroidal anti-inflammatory drugs (NSAIDS), or any steroidal drugs 24 hours prior to enrollment. Patient has been diagnosed with any stroke within the prior 3 months. Patient has active bleeding or bleeding diathesis. Patient has experienced trauma or major surgery in the preceding month. Patient has severe, uncontrolled hypertension (systolic blood pressure of more than 180 mm Hg). Patient's creatinine \> 2.0 mg/dl prior to PCI. Patient has a hemoglobin level of less than 10.0 g per deciliter or a hematocrit below 30 percent. Patient has a platelet count of less than 100,000 per cubic millimeter or more than 600,000 per cubic millimeter. Of note, patients on chronic clopidogrel will only be eligible for VerifyNow P2Y12 testing. Clopidogrel non-responsiveness in this group will be defined as \< 20% inhibition \-