Impact of Ticagrelor on the Endothelial Healing Following Drug-eluting Stent Implantation in the Patients With Acute Coronary Syndrome

The investigators hypothesized that ticagrelor may enhance endothelial healing after DES implantation by increasing adenosine concentrations by the inhibition of adenosine uptake into erythrocytes, compared to clopidogrel. Thus, the investigators will evaluate the extent of endothelialization (stent strut coverage) and neointimal hyperplasia (neointimal thickness) 3 months after DES implantation by optical coherence tomography (OCT)

Inclusion Criteria:

• Patients ≥ 20 years old
• Patients who are hospitalized and expected to undergo PCI for acute coronary syndrome, including acute myocardial infarction and unstable angina.

Exclusion Criteria:

• Age > 80 years
• Cardiogenic shock or unstable patients
• Increased risk of bleeding, anemia, thrombocytopenia
• A need for oral anticoagulation therapy
• Pregnant women or women with potential childbearing
• Life expectancy < 1 year