Clinical Research Directory

Inclusion Criteria: 1. Subject must be at least 19 years of age 2. Eligible for coronary angiography and/or percutaneous coronary intervention. 3. Chronic coronary syndrome or acute coronary syndrome (non-culprit vessels only) 4. Coronary artery disease in one or more native major epicardial vessels or their branches with reference vessel diameter of at least 2.5mm and with visually assessed coronary stenosis in which the physiological severity of the lesion is questionable (typically 40-90% diameter stenosis). 5. Subject who is able to understand risks, benefits and treatment alternatives and sign informed consent voluntarily. Exclusion Criteria: 1. Patients unable to provide informed consent 2. Patients with known intolerance to aspirin, P2Y12 inhibitors, or components of drug-eluting stents and drug-coated balloons 3. Patients with coronary artery bypass grafting 4. Patients who have non-cardiac co-morbid conditions with life expectancy \<1 year 5. Patients with cardiogenic shock or cardiac arrest 6. Patients with severe left ventricular systolic dysfunction (ejection fraction \<30%) 7. Patients with severe valvular heart disease requiring open heart surgery 8. Pregnant or lactating women 9. Angiographic exclusion criteria * Culprit vessel of patients with ST-elevation myocardial infarction (target lesions in non-culprit vessel can be enrolled) * Chronic total occlusion (target lesions in vessels without chronic total occlusion can be enrolled) * Ostial stenosis in left man coronary artery or right coronary artery * Severe tortuosity of any target vessel * Severe overlap in the stenosed segment * Poor image quality precluding identification of vessel contours