Assessment of Stent Malapposition and Neointimal Coverage on Optical coHerence Tomography at Post-procedure and 3 Months After Platinum Chromium Alloy Of the Element™ Stent Implantation

Inclusion Criteria: * Patient is ≥ 20 years old * Significant coronary de novo lesion (\> 70% by quantitative angiographic analysis) treated by single DES in each vessel. * Patients with stable angina who are considered for coronary revascularization with stent implantation. * Reference vessel diameter of 2.5 to 3.5 mm by operator assessment Exclusion Criteria: * Complex lesion morphologies such as aorto-ostial, unprotected left main, chronic total occlusion, graft, thrombosis, and restenosis * Reference vessel diameter \< 2.5 mm or \> 4.0mm and lesion length \> 28 mm * Heavy calcified lesions (definite calcified lesions on angiogram) * Lesions requiring more than 2 DES in each vessel * Acute coronary syndrome * Contraindication to anti-platelet agents * Treated with any DES 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 * Life expectancy 1 year