To compare the efficacy and safety of clopidogrel monotherapy versus aspirin plus P2Y12 antagonist following 3-month of DAPT in patients undergoing PCI with DES.

This trial is a prospective, randomized, multi-center, open label, noninferiority trial. Patients undergoing PCI with DES will be eligible. After successful PCI with DES, all eligible patients will be randomized either to clopidogrel monotherapy or to aspirin plus P2Y12 antagonist following 3-month of DAPT.

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