This prospective observational cohort study, will investigate the platelet phenotype, platelet genetic composition, and role of platelets as effector cells in women and men with myocardial infarction (MINOCA or MI-CAD) and controls. This study, which will take place at NYU and Bellevue Medical Center, and participating external sites. May have concurrent enrollment with the HARP Main Imaging (NCT02914483). Additionally, a sex, group of age and race matched disease controls 'CATH-NOCA' composed of women and men with stable angina referred for cardiac catheterization, will be enrolled. Blood obtained during the initial catheterization and 2 months post-MI will be utilized for platelet testing.

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

This study may have concurrent enrollment with the HARP Main Imaging (NCT02905357). This study population includes women and men who present to the hospital with an MI, with non-obstructive coronary artery disease or obstructive artery disease, are eligible for blood collection. Additionally, a sex, group of age and race matched disease controls 'CATH-NOCA' will be composed of women and men with stable angina referred for cardiac catheterization.

De-identified data will be shared after the end of the study.