Heart Attack Research Program: Platelet Sub-Study (HARP)

Inclusion Criteria

• Acute ischemic symptoms compatible with diagnosis of MI, such as chest pain or anginal equivalent symptoms at rest or new onset exertional anginal equivalent symptoms
• Objective evidence of MI (either or both of the following):

• Elevation of troponin to above the laboratory upper limit of normal (ULN)
• ST segment elevation of ≥1mm on 2 contiguous ECG leads
• Willing to provide informed consent and comply with all aspects of the protocol
• Administration of aspirin at least 1 hour before cardiac catheterization
• Administration of thienopyridine (e.g., clopidogrel, ticagrelor) at least 1 hour before cardiac catheterization
• Women and men with ≥50% of any major epicardial vessel on invasive angiography may participate

Exclusion Criteria

• Recent use of vasospastic agents, such as cocaine, triptans, or ergot alkaloids (≤1 month)
• Alternate explanation for troponin elevation, such as hypertensive urgency, acute exacerbation of heart failure, chronic elevation due to kidney disease, pulmonary embolism, cardiac trauma
• Pregnancy
• Thrombolytic therapy for STEMI (qualifying event)
• Use of any of the following medications:
• Platelet antagonists (except aspirin and thienopyridines) within 7 days
• NSAIDs (e.g., ibuprofen, naproxen) within 3 days.
• Thrombocytopenia (platelet count \<100,000)
• Thrombocytosis (platelet count >500,000)
• Anemia (hemoglobin \<9 mg/dl)
• Hemorrhagic diathesis