The DISCOVER INOCA Prospective Multi-center Registry

Inclusion Criteria: * Suspected ischemic heart disease and is referred to undergo clinically indicated invasive coronary angiography * No obstructive coronary artery disease (CAD) as defined by operator visual assessment with (1) angiographically normal coronary arteries OR (2) non-obstructive CAD with angiographic stenosis \< 50%, or greater than or equal to 50 but \< 70% with FFR greater than or equal to 0.81 or RFR greater than or equal to 0.90 * Willing to comply with specified follow-up evaluations. The participant or legally authorized representative has been informed of the nature of the study, agrees to its provisions, and has been provided written informed consent approved by the appropriate Institutional Review Board (IRB) or Ethics Committee (EC) Exclusion Criteria: * Pregnant or nursing * Any myocardial infarction at index presentation or within 90 days prior to enrollment, defined as any electrocardiogram diagnostic for myocardial infarction OR elevation in serum troponin greater than the upper limit of the site-defined reference range * Known left ventricular ejection fraction \< 50% or cardiogenic shock requiring pressors or mechanical circulatory assistance (e.g., intra-aortic balloon pump, left ventricular assist device, other temporary cardiac support blood pump) * Renal insufficiency, defined as estimated glomerular filtration rate (eGFR) \<30 mL/min/1.73 m2 (by the Modification of Diet in Renal Disease equation) or dialysis at the time of screening * Pr…