Relationship between hyporesponsiveness to clopidogrel measured by thrombelastography and in stent restenosis in patients undergoing percutaneous coronary intervention

Objectives: The relationship between hyporesponsiveness to clopidogrel and in stent restenosis (ISR) was analyzed, and the cut-off value of hyporesponsiveness to clopidogrel for ISR was evaluated. Design and methods: 861 consecutive patients enrolled and patients' inhibition rates in arachidonic acid (AA) and adenosine 5'-diphosphate (ADP) pathways were measured by thrombelastography (TEG) system. Patients were divided into ISR and non-ISR groups according to the results of coronary angiography. Correlation between hyporesponsiveness to clopidogrel and ISR was analyzed. Results: 249 patients were in ISR group and 612 patients were in non-ISR group. The frequency of clopidogrel hyporesponsiveness in ISR group was significantly higher than that in non-ISR group (P < 0.01). Inhibition rates in AA and ADP pathways in ISR group were lower than those in non-ISR group (P < 0.01). The inhibition rate in ADP pathway was inversely correlated with (r = -0.225, P = 0.001) the severity of ISR. After being adjusted for traditional covariates, the inhibition rate in ADP pathway (beta = -0.191, R-2 = 0.011, P = 0.013) remained independently associated with the severity of ISR; clopidogrel hyporesponsiveness was an independent risk factor of ISR (HR 6.62,95% Cl 2.84-15.49, P = 0.001). ROC curve analysis showed that the predictive cut-off value of the inhibition rate in ADP pathway for ISR was 10.1%. Conclusions: The inhibition rate in ADP pathway is inversely related to the ISR severity. Clopidogrel hyporesponsiveness is an independent risk factor for ISR and can predict the risk of ISR (C) 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.