The purpose of this study in to evaluate efficacy and tolerability of Clopirin and clopidogrel with aspirin in Korean Patients with post-percutaneous coronary artery intervention.

Inclusion Criteria:

• Over 3 months, the patient who were the administration of aspirin or the co-administration of clopidogrel-aspirin coronary artery patients after treated with Percutaneous Coronary Intervention(PCI) that have safety progress.
• Korean men and women between the age of 20 and 85
• Patients who understand the study requirements, are willing to comply with all study procedures and have provided written informed consent.

Exclusion Criteria:

• Patients who were not treated with PCI or intended to treat with PCI but failed.
• Patients who were taking or had taken other antiplatelet or anticoagulant for more than 2 weeks within the prior 30 days.
• Patients who had a history of alcohol abuse or intoxication.
• Patients who had hypersensitivity to clopidogrel or aspirin.
• Patients who had severe hepatic dysfunction aspartate aminotransferase(AST) or alanine aminotransferase(ALT) > 3 times upper normal reference values.
• Patients who had blood coagulation disorders, uncontrolled severe hypertension, active bleeding, or history of severe bleeding, such as intracranial hemorrhage or ulcer bleeding - surgery within 48hr, platelet counts below 50,000/mm3 in laboratory tests.
• Patients who were pregnant, breastfeeding.
• Patients who were not using effective methods of contraception. (proper contraception : hormonal contraception, condom, intrauterine device, spermicide)
• Patients who medically, psychologically had investigational product administration's prohibition.
• Patients who were not participated in this clinical trial decided by other investigators.