 The fatality of stent thrombosis ST in patients with coronary artery disease CAD undergoing percutaneous coronary intervention PCI is approximately 50 and clopidogrel is an important anti-platelet drug for prevention of ST. CAD patients implanted with stent including bare metal stent BMS and drug eluting stent DES are recommended to receive dual anti-platelet treatment DAPT, i.e. clopidogrel along with aspirin, for at least one year to reduce the incidence of ST by up-to-date guidelines. However, due to the variability of anti-platelet effect of clopidogrel, regular dose 75 mg daily of clopidogrel administered cannot achieve enough inhibition of platelet aggregation in 20-30 of total patients, which is named as clopidogrel low responsiveness CLR, and the morbidity of thrombosis including in CAD patients is still 10. 