Serial EValuation of multiplE Coronary Artery Diseases by an Optical Coherence Tomography; Assessment of the Changes of de Novo Lesions and Comparisons of Neointimal Coverage Between Xience Prime® Versus Cypher SelectTM Stents; SEVEN-Xience Study

Inclusion Criteria: * Patient is ≥ 20 years old * Patients with typical angina who are considered for coronary revascularization. * Multi-vessel diseases: more than 2 significant coronary de novo lesions (\> 70% by quantitative angiographic analysis); one of the target lesions is the most significant tight stenotic lesion causing the ischemic symptom and requiring the immediate revascularization but the others are significant but non-tight lesions to be delayed or observed for 3 months and not requiring immediate PCI for the complete revascularization of all coronary arteries. Exclusion Criteria: * ST-elevation MI * Cardiogenic shock or hemodynamically unstable status * Lesions requiring the immediate complete revascularization of all coronary stenotic lesions * Contraindication to anti-platelet agents * Treated with any DES within 6 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 * Life expectancy 1 year * Complex lesion morphologies (bifurcation lesions treated with 2-stent techniques, untreated significant unprotected left main diseases, chronic total occlusion, in-stent restenosis, and vein graft lesion)