Platelet reactivity will be measured after 7-days treatment of clopidogrel by VerifyNow system and the cohort will be divided by two group according to P2Y12 reactivity unit (PRU) cutoff value. Receiver operating characteristic (ROC) curves will be plotted to assess the optimal PRU cutoff value for differentiating between patients with and without subsequent MACEs after 1 year of follow-up. Low platelet reactivity indicates good response to clopidogrel and high platelet reactivity, resistance to clopidogrel. Groups will be "Low platelet reactivity group" and "High platelet reactivity group"

Platelet reactivity will be measured after 7-days treatment of clopidogrel by VerifyNow system and the cohort will be divided by two group according to P2Y12 reactivity unit (PRU) cutoff value. Receiver operating characteristic (ROC) curves will be plotted to assess the optimal PRU cutoff value for differentiating between patients with and without subsequent MACEs after 1 year of follow-up. Low platelet reactivity indicates good response to clopidogrel and high platelet reactivity, resistance to clopidogrel. Groups will be "Low platelet reactivity group" and "High platelet reactivity group"

aspirin 100mg/day and clopidogrel 75mg/day, PO, from the day of surgery for 1 year

The primary endpoint of the study was the 1-year incidence of MACEs, which included the following: (1) cardiac death, defined as death in the presence of acute coronary syndrome, sudden cardiac arrest with documented cardiac arrhythmia, or refractory congestive heart failure; 2) nonfatal MI; and (3) target vessel revascularization in relation to platelet reactivity as measured by the VerifyNow system.