Identification Of Clopidogrel Resistance In 90 Patients Undergoing Percutaneous Coronary Intervention

Objective:To investigate the incidence of clopidogrel resistance in coronary heart disease suffers,platelet function profiles were assessed in 90 patients undergone percutaneous coronary intervention,who had taken 300 mg clopidogrel before,and 75 mg after the operation,lasting for 12 months at least.The indicators of clopidogrel resistance and its relation with the ischemic events were also discussed.Methods:Platelet aggregation was assessed by light transmittance aggregometry following 6μmol/L ADP stimuli in 90 patients undergone non-emergency coronary stents implanting before,12 hours and 5 days after receiving clopidogrel front-loading.Patients having＞10%inhibition of platelet aggregation 5 days after clopidogrel administration were defined as normal responders,whereas those having≤10%inhibition were clopidogrel resistance patients.PAC-1 and CD62P were assessed by whole blood flow cytometry at the same time points.Platelet function profiles were compared between normal and clopidogrel resistance patients.The occurrence of ischemic events was also compared at 30-day and 6-month follow-up after percutaneous coronary intervention.Results:Twenty-four patients(26.7%)were clopidogrel resistance patients and sixty-six patients were normal responders(73.3%).Baseline CD62P was higher in clopidogrel resistance patients(26.4±8.1%vs 17.0±5.8%,P＜0.001).Although CD62P reduced following clopidogrel front-loading in both groups,it remained higher among clopidogrel resistance patients(6.57±1.21%vs4.73±0.57%,P=0.011)in 12 hours after receiving clopidogrel front-loading and it also higher among these individuals (3.32±0.73%vs2.20±0.31%,P=0.003)in 5 days after clopidogrel administration. Baseline PAC-1 was higher in clopidogrel resistance patients(14.9±3.1%vs8.5±1.1%,P=0.037).Although PAC-1 reduced following clopidogrel front-loading in both groups,it remained higher among clopidogrel resistance patients(11.49±2.25%vs7.36±1.77%,P=0.03)in 12hours after receiving clopidogrel front-loading and it also higher among these individuals(4.86±1.13%vs4.02±1.01%,P=0.045)in 5 days after clopidogrel administration.Patients were followed for 30 days and 6 months after percutaneous coronary intervention,the clopidogrel resistance patients were at increased risk for ischemic events(41.7%v 11.21%,P=0.001;56.5 vs 22.2%,P=0.023).Conclusions:A considerable proportion patients have a clopidogrel resistance to a 300 mg clopidogrel loading dose.Increased PAC-1 and CD62P before clopidogrel front-loading may identify this group of patients and the evaluation of clopidogrel resistance patients may help to identify these individuals at increased risk who may benefit from intensified antiplatelet strategy.