It is well-known that non-optimal stent implantation associated with under-expansion or incomplete strut apposition during percutaneous coronary intervention (PCI) leads to a higher incidence of restenosis and stent thrombosis. OCT-guided PCI with metallic stent has previously been shown to be safe and feasible, resulting in better clinical outcomes compared with angiography-only guided PCI. Everolimus-eluting bioabsorbable vascular scaffold (BVS; Abbott Vascular, Santa Clara, CA, USA) was made from a bioabsorbable polylactic acid backbone which is coated with a more rapidly absorbed polylactic acid layer that contains and controls the release of the antiproliferative drug, everolimus. BVS has a number of proposed advantages over current metallic stent technology. These include elimination of chronic sources of vessel irritation and inflammation, which can reduce the potential risk of late scaffold thrombosis after complete scaffold bioresorption. Although the current generation of the Absorb BVS have larger strut thickness of 150 μm compared with 80 μm of strut of Xience stent, the acute recoil of the polymeric device was similar to that of metallic stent. However, operators tented to use dilating devices less aggressively because of the concerns about limitation in elongation-at-break of polylactide. Previous studies reported 20-30% of under-expansion or malapposition with BVS, which would increase the risk of adverse events including late stent thrombosis. OCT-guidance may improve more optimized scaffold placement and also better outcomes. Therefore, investigators will compare OCT guidance and angiography-only guidance for PCI with BVS regarding incomplete scaffold apposition and neointimal scaffold coverage. Investigators are also going to compare these two strategies regarding clinical outcomes with verification of the cut-off value by OCT-acquired uncovered scaffold rate.

Inclusion Criteria:

• Patients ≥ 19 years old
• Patients with ischemic heart disease who are considered for coronary revascularization with PCI
• Significant coronary de novo lesion (stenosis > 70% by quantitative angiographic analysis) treated by single BVS ≤ 25mm
• Reference vessel diameter of 2.5 to 3.5 mm by operator assessment

Exclusion Criteria:

• Myocardial infarction
• Complex lesion morphologies such as aorta-ostial, unprotected left main, chronic total occlusion, graft, thrombosis, and restenosis
• Reference vessel diameter <2.5 mm or >3.5 mm
• Heavy calcified lesions (definite calcified lesions on angiogram)
• Lesions requiring 2 or more BVS
• Contraindication or hypersensitivity to anti-platelet agents or contrast media
• Treated with any metallic stent or BVS within 3 months at other vessel
• Creatinine level ≥ 2.0 mg/dL or ESRD
• Severe hepatic dysfunction (3 times normal reference values)
• Pregnant women or women with potential childbearing
• Inability to follow the patient over the period of 1 year after enrollment, as assessed by the investigator
• Inability to understand or read the informed content