HOW To Optimally Implant BioResorbable Scaffold - Intravascular Imaging Versus Quantitative Coronary Angiography Guidance

Inclusion Criteria: * Men or women at least 19 years of age * Typical chest pain or objective evidence of myocardial ischemia suitable for elective percutaneous coronary intervention * Native coronary artery lesions with lesion length 50mm and less and reference vessel diameter of 2.5 \~ 3.75mm by quantitative coronary angiography assessment * The patient or guardian agrees to the study protocol and the schedule of clinical follow-up, and provides informed, written consent, as approved by the appropriate Institutional Review Board/Ethical Committee of the respective clinical site. Exclusion Criteria: * Angiographic exclusion criteria: any of the followings 1. Small vessel: mean reference size \< 2.5 mm by quantitative coronary angiography 2. True bifurcation lesion with a large side branch (reference vessel diameter \> 2.3mm) requiring a complex two-stent approach 3. Left main lesions 4. Ostial lesions within 3mm of the origin: right coronary artery, left anterior descending, or left circumflex artery 5. Impaired delivery of the Absorb bio- resorbable vascular scaffold is expected: * Extreme angulation (≥90°) proximal to or within the target lesion. * Excessive tortuosity (≥two 45° angles) proximal to or within the target lesion. * Moderate or heavy calcification proximal to or within the target lesion. 6. In-stent restenotic lesions * ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (with 12- 24 hour after symptoms onset) * Prior percutaneous coronary intervention within the target vessel during the last 12 months. * Prior percutaneous coronary intervention within the non-target vessel or any peripheral intervention is acceptable if performed anytime \>30 days before the index procedure, or between 24 hours and 30 days before the index procedure if successful and uncomplicated. * Left ventricular ejection fraction (LVEF) \< 30% * Hypersensitivity or contraindication to device material and its degradants (everolimus, poly (L-lactide), poly (DL-lactide), lactide, lactic acid) and cobalt, chromium, nickel, platinum, tungsten, acrylic and fluoro polymers that cannot be adequately pre-medicated. * Persistent thrombocytopenia (platelet count \<100,000/µl) * Any history of hemorrhagic stroke or intracranial hemorrhage, transient ischemic attack or ischemic stroke within the past 6 months * A known intolerance to a study drug (aspirin, clopidogrel or ticagrelor) * Patients requiring long-term oral anticoagulants or cilostazol * Any surgery requiring general anesthesia or discontinuation of aspirin and/or an Adenosine diphosphate(ADP) antagonist is planned within 12 months after the procedure. * A diagnosis of cancer (other than superficial squamous or basal cell skin cancer) in the past 3 years or current treatment for the active cancer. * Any clinically significant abnormality identified at the screening visit, physical examination, laboratory tests, or electrocardiogram which, in the judgment of the Investigator, would preclude safe completion of the study. * Hepatic disease or biliary tract obstruction, or significant hepatic enzyme elevation (alanine transaminase (ALT) or aspartate transaminase (AST) \> 3 times upper limit of normal). * Life expectancy \< 5 years for any non-cardiac or cardiac causes * Unwillingness or inability to comply with the procedures described in this protocol. * Patient's pregnant or breast-feeding or child-bearing potential.