Thrombocyte Activity Reassessment and GEnoTyping for PCI(TARGET-PCI)

Inclusion Criteria: * Patients must be between ages 18-85. * Patients undergoing PCI. * Patients undergoing coronary angiography and possible PCI with planned use of at least one drug-eluting stent (DES). One or more bare metal stents (BMS) may be implanted, and other lesions may be treated without stenting, as long as at least one DES is implanted. However the procedure must be successful and uncomplicated for all lesions (DES + BMS + non stent). * Indication for the procedure may be stable angina or ischemia, unstable angina, non-ST elevation MI (NSTEMI). * Have the ability to understand the requirements of the study, including consent for use and disclosure of research-related health information. * Have the ability to comply with study procedures and protocol, including required study visits. * A female patient is eligible to enter the study if she is (1) of child-bearing potential and not pregnant or nursing; (2) not of child bearing potential (i.e. has had a hysterectomy, have both ovaries removed, has tubal ligation, or if she is post-menopausal, defined as 24 months without menses). Exclusion Criteria: * Cardiovascular * Cardiogenic shock. * Ischemic Stroke within 6 weeks * Planned staged PCI in the next 6 months post-procedure * Unsuccessful PCI (post-procedure diameter stenosis \>30% with less than TIMI-3 flow in any treated vessel). * Patients with in-hospital STEMI confirmed by ECG prior to randomization or those whom require a target vessel revascularization of the index lesion prior to randomization. * Major complication during or after PCI such as but not limited to need for balloon pump, acute stent thrombosis, and major bleed. * Prior or concomitant therapy * Concurrent or planned treatment with warfarin. * IIb/IIIa Inhibitors within 72 hrs of PCI * Current or planned treatment with Cilostazol * Current treatment with Prasugrel * Hemorrhagic risk * History of bleeding diathesis or evidence of active abnormal bleeding within 30 days of randomization. * History of hemorrhagic stroke or sub-arachnoid hemorrhage at any time or stroke or TIA of any etiology within 30 days of randomization. * Major surgery within 6 weeks prior to randomization. * Known platelet count of \<100,000/mm3. * PT \> 1.5 x control. * HCT \< 25% or \> 52%. * History of gastro-intestinal bleeding within 6 months. * Considered by investigator to be at high-risk for bleeding on long-terms clopidogrel therapy. * Minor surgical procedures that require cessation of dual antiplatelet therapy and result in significant bleeding are NOT eligible. * General * Known allergy or contraindication to heparin, aspirin, clopidogrel, or prasugrel. * Participation in a study of experimental therapy or device within prior 30 days. * Creatinine level of greater than 4.0 mg/dl. * Known history of alcohol or drug abuse. * Pregnant women or women of child-bearing potential not using an acceptable method of contraception. * Severe allergy to stainless steel, contrast dye, unfractionated heparin, low molecular weight heparin, or bivalirudin that cannot be adequately pre-medicated. * Current enrollment in an investigational drug or device study that has not reached the time period of the primary endpoint. * Patients unwilling or unable to complete clinical follow-up for the duration of the study.