Angiogram Based Fractional Flow Reserve in Patients With Multi-Vessel Disease

Inclusion Criteria: * \>18 years of age. * Patients with stable angina or unstable angina or NSTEMI, with at least 1 stenoses ≥ 50% in two main vessels (LAD, LCX and/or RCA) each and in whom invasive FFR is being assessed at these stenoses. * Patients undergoing invasive FFR with Adenosine, ATP or Papaverine used as hyperemic stimulus. * Written, informed consent. Exclusion Criteria: * Contraindication for FFR examination or administration of vasodilators. * Clinical presentation of an acute infarct (STEMI) or presented with STEMI in past year. * CTO in a target vessel. * Prior CABG, valvular surgery, TAVI/TAVR, or heart transplantation. * Known LVEF ≤45%. * Arteries supplying akinetic or severe hypokinetic territories if already known based on prior imaging. * TIMI Grade 2 or lower at baseline. * Target lesions involve Left Main (stenosis ≥50%.) * In-stent restenosis in a target vessel. * Heavily diffused atherosclerosis diseases defined as the presence of diffuse, serial gross luminal irregularities present in the majority of the coronary tree. * Target coronary vessels are supplied by major collaterals. * Lesion is in ectatic segment which includes dilatation in diameter at least 1.5 times that of the adjacent normal coronary artery. * Coronary angiograms not acquired per instructions as defined in the Study Protocol.