Functional ComprEhensive AssessmenT by IVUS Reconstruction in Patients With Suspected IschEmic Heart Disease (FEATURE)

Investigating the diagnostic accuracy of online Ultrasonic Flow Ratio (UFR) assessment to identify hemodynamically significant coronary stenosis in patients with suspected ischemic heart disease using angiography-derived fractional flow reserve (FFR) as a reference standard.

Inclusion Criteria: * Subject must be ≥ 18 years * Patients suspected with ischemic heart disease * ≥ 1 diseased vessel with angiographic percent diameter stenosis between 40% and 80% in a vessel ≥ 2.5mm by visual estimation * Target vessels are limited to major epicardial coronary arteries (left anterior descending artery \[LAD\], left circumflex artery \[LCX\], right coronary artery \[RCA\]) Exclusion Criteria: * Patients with previous coronary artery bypass grafting (CABG) * Myocardial infarction within 72h of coronary angiography * Allergy to the contrast agent or adenosine * Left main coronary artery stenosis ≥ 50% * Target vessel with in-stent restenosis * Target vessel with severe tortuosity or angulation * 100% occlusion of target vessel * Target vessel spasm or injury * Target vessel with severe myocardial bridge * Target vessel with severe thrombosis * Intravascular ultrasound (IVUS) pullback fails to cover the complete target lesion * Presence of false lumen at target vessel based on IVUS * A serum creatinine level \>150 umol/l, or a glomerular filtration rate \< 45 ml/kg/1.73 m\^2 * Heart failure * Ineligible for diagnostic intervention (IVUS or FFR examination)