Comparison Between P2Y12 Antagonist Monotherapy and Dual Antiplatelet Therapy After DES

Inclusion Criteria: * Subject must be at least 20 years of age. * Subject is able to verbally confirm understandings of risks, benefits and treatment alternatives and he/she or his/her legally authorized representative provides written informed consent prior to any study related procedure. * Patients undergoing successful PCI Exclusion Criteria: * Hemodynamic instability or cardiogenic shock * Active bleeding * Known hypersensitivity or contraindication to study medications * Female of childbearing potential, unless a recent pregnancy test is negative, who possibly plan to become pregnant any time after enrollment into this study * Non-cardiac co-morbid conditions are present with life expectancy \<2 year or that may result in protocol non-compliance (per site investigator's medical judgment). * DES implantation within 12 months before index procedure