Registry of Comprehensive Imaging and Physiological Evaluation of Deferred Lesions Based on FFR

Inclusion Criteria: * Subject must be ≥ 18 years * Patients suspected with ischemic heart disease * Patients with intermediate degree of stenosis (30-70% stenosis by visual estimation) with fractional flow reserve of \>0.80 in major epicardial coronary artery amenable to stent implantation or vessel size≥2.5 mm * Patients whose coronary stenosis were evaluated by invasive imaging techniques (intravascular ultrasound and optical coherence tomography) and physiologic assessment (coronary flow reserve, index of microcirculatory resistance, and fractional flow reserve) * Subject is able to verbally confirm understandings of risks, benefits and treatment alternatives of receiving invasive physiologic or imaging evaluation and he/she or his/her legally authorized representative provides written informed consent to any study related procedure Exclusion Criteria: * End-staged renal disease on peritoneal dialysis or hemodialysis (estimated GFR \< 15mL/min) * Acute hepatic injury * Cardiogenic shock (systolic blood pressure \< 90mmHg or requiring inotropics to maintain blood pressure \> 90mmHg) * The patient has a known hypersensitivity or contraindication to any of the following medications: statin, ezetimibe, heparin, aspirin, clopidogrel, prasugrel, ticagrelor * Non-cardiac co-morbid conditions are present with life expectancy \<2 year (per site investigator's medical judgment) * Unable to perform invasive imaging study (intravascular ultrasound and optical coherence tomography) or physiologic assessment (coronary flow reserve, index of microcirculatory resistance, and fractional flow reserve)