The study aims to determine the feasibility and clinical utility of incorporating precision medicine approaches, incorporating both cytochrome P450 2C19 (CYP2C19) genotyping and platelet reactivity phenotyping, with standard of care for patients with acute coronary syndromes (ACS), post PCI.

Study Population:

Adult patients will be eligible for inclusion if they provide informed consent and have no contraindications for 12-months of dual antiplatelet therapy (DAPT).

Baseline Evaluation:

Overview of clinical protocol: Patients with successful PCI will receive a genotype guided recommendation, upon discharge, based on CYP2C19 genotype. Patients who are determined to have CYP2C19 poor metabolizer (PM) or intermediate metabolizer (IM) status will be recommended to receive 12-months of prasugrel. Patients who are determined to have CYP2C19 normal metabolizer (NM), rapid metabolizer (RM), or ultra-rapid metabolizer (UM) phenotype will be recommended to receive a de-escalation treatment, guided by on-treatment platelet reactivity phenotype at 14 days, post discharge.

30-day, 6-month, and 12-month Follow-up: Patients will be contacted by phone or visited during one of their regularly scheduled appointments, at 14 days, 30 days, 6 months , and 12 months, to complete "Follow-up Case Report Forms" to collect outcomes data. The 12-month follow up communication with enrolled patients will end their participation in the study.

Inclusion Criteria:

1. Patients with troponin positive ACS
2. Patients scheduled for left heart catheterization and undergoing PCI
3. Age 18-80 years at time of enrollment
4. Currently receiving or anticipated to receive DAPT, with P2Y12 inhibitor
5. Ability to follow-up for a clinic visit with LAC+USC outpatient cardiology
6. Written informed consent

Exclusion Criteria:

1. Subjects with known contraindications to clopidogrel treatment, which are hypersensitivity to the drug substance or any component of the product and active pathological bleeding such as peptic ulcer or intracranial hemorrhage
2. Subjects with known contraindications to prasugrel treatment, which are hypersensitivity to the drug substance or any component of the product, active pathological bleeding such as peptic ulcer or intracranial hemorrhage, and a history of prior transient ischemic attack (TIA) or stroke
3. Subjects with a history of a complicated or prolonged cardiogenic shock in the last two weeks prior to enrolling in this study. A complicated or prolonged cardiogenic shock is defined by a cardiogenic shock that required mechanical ventilation or the cardiovascular support with positive inotropic drugs (i. v. catecholamines) for ≥7 days.
4. Subjects requiring concomitant treatment with an anticoagulant agent (Vitamin-K antagonists or novel oral anticoagulants such as rivaroxaban, dabigatran or apixaban)
5. Indication for major surgery (per decision of the treating physician) for the planned duration of the study
6. Subject with history of liver transplant or plan to undergo liver transplant during the next 12 months
7. Evidence of significant active neuropsychiatric disease, in the investigator's opinion.

Study protocol is anticipated to be published within 12 months of completing the study, and not anticipated to have a time limit.