To investigate whether instantaneous wave-Free Ratio(iFR)/Fractional Flow Reserve(FFR) guided treatment strategy makes the postulated treatment strategy by Coronary Angiogram(CAG) guide change and to analyze the cost-effectiveness of its dual diagnosis.

To investigate difference between SYNTAX score evaluated CAG and functional SYNTAX score evaluated physiological assessment of coronary stenosis and its clinical effectiveness.

Inclusion Criteria:

• Age>=20 years old.
• Patient who can understand informed consent of the clinical study and signed the consent.
• Patient who is adaptable to CAG and/or coronary revascularization
• Patient who has evaluated stenotic lesion (stenosis>50% in visual judgment) by CAG at main epicardial vessel and its branch or who suspected to have it.

Exclusion Criteria:

• Patient with known contraindications to Adenosine Triphosphate(ATP) and/or papaverine hydrochloride
• Target vessel diameter<=2.0mm
• Lesion with Chronic Total Occlusion(CTO) (registration allowed if other branch has stenosis more than 50% in visual judgment)
• Patient with temporary/permanent artificial pacemaker implantation, left bundle branch block, second-degree and third-degree atrioventricular block.
• Acute Myocardial Infarction(AMI) patient
• Patient who is disqualified for FFR and coronary revascularization by the investigator.
• Lesion is disqualified for Percutaneous Coronary Intervention(PCI) by the investigator.
• Patient who has critical valvular disease of heart. (moderate or severe Aortic valve stenosis(AS)/Aortic Regurgitation(AR)/Mitral Stenosis(MS)/Mitral Regurgitation(MR)）
• Patient with a prior Coronary Artery Bypass Graft(CABG) on target vessel.
• Patient with severe renal dysfunction. (serum creatinine>=2.0mg/dl)
• Patient on hemodialysis.
• Body weight>=200kg
• Patient who needs ventricular assist device to ensure hemodynamic stability (heart rate<50/min, SBP<90mmHg)
• Patient who expects to live less than 2 years at the registration
• Patient with contraindications to an antithrombotic therapy or an anticoagulant therapy.
• Patient who is poor compliance with drug treatment.
• Patient who is allergic to contrast agent.
• Left Ventricular Ejection Fraction(LVEF)>=30%
• Patient who has the history of PCI with Drug-Eluting Stent(DES) in recent 3 months before registration.
• Patient who has the history of PCI with Bare Metal Stent(BMS) or Plain Old Balloon Atherectomy(POBA) in recent 1 year before registration.
• Patient who has possibility of pregnancy, under breast-feeding and positive pregnancy test in 14days prior to the PCI.
• Patients with inadequacy to join this clinical study.
• Patient who has been enrolled any other clinical study.

Patient who is adaptable to CAG and/or coronary revascularization