Optimal Duration of DAPT Following Treatment With Endeavor (Zotarolimus-eluting Stent) in Real-world Japanese Patients

Inclusion Criteria: 1. Clinical inclusion criteria * Patient over age 20 years. * Patient who is clinically indicated for PCI by stenting at least in one coronary lesion that is visually confirmed by coronary angiography. * Patient who has agreed to conditions after receiving an explanation about the contents of the present clinical study and who has signed the consent form approved by the ethical review board at each study site. * Patient who has agreed to undergo all clinical FUs listed in the present protocol. 2. Coronary angiographic inclusion criteria: * Patient who has a \> 50% occlusion or stenosis that is visually confirmed by coronary angiography in a native coronary artery \> 2.5 mm in diameter and in whom the relevant coronary artery has an anatomical structure that is eligible for PCI with Endeavor Zotarolimus-eluting stent. Exclusion Criteria: 1. Clinical exclusion criteria * Patient over age 85 years. * Patient with ST elevation MI who requires primary or rescue PCI and whose performance status falls under any of the exclusion criteria. * Patient with cardiogenic shock. * Patient who underwent stent treatment with BMS in other lesions within 6 months prior to the conduct of index PCI of the target vessel. * Patient who has undergone some treatment with DES for coronary lesions. * Patient who is scheduled to undergo elective surgery within 12 months after index PCI. * Patient whose left ventricular ejection fraction (LVEF) is \< 40%. * Patient with a hemorrhagic predisposition or a history of coagulation abnormality * Patient in whom the total number of deployed stents exceeds 4,regardless of the number of lesions and the number of affected branches. * Patient with a verified history of CVA before stenting. * Patient with a verified history of active peptic ulcer or upper gastrointestinal tract bleeding before Stenting. * Patient showing impaired renal function. (serum creatinine concentration: \> 1.8 mg/dL) * Patient with known contraindications for aspirin or clopidogrel. (the physician should assess tolerability within the range of routine medical care) * Patient with a known disorder who has a life expectancy of less than 12 months. * Patient who is incompetent to adhere to all clinical FUs listed in the present protocol. 2. Angiographic exclusion criteria: * Lesions located within the saphenous venin graft (SVG). * Unprotected lesions in the left coronary trunk. * Lesions of in-stent restenosis in previously deployed DES or BMS. * Lesions with an anatomical structure of the coronary artery that is not eligible for treatment by the deployment of Endeavor ZES.