Low Response to Clopidogrel in Coronary Artery Disease

Background: In patients with coronary artery disease, cardiovascular mortality and other acute events showed a clear correlation with risk factors and biomarkers including platelet activation. Study Question of This Research: Which was the incidence of low response to clopidogrel and its correlation with risk factors and biomarkers in coronary artery disease? Study Design: Four hundred patients (pts) with coronary artery disease-stable angina (SA) and acute coronary syndrome-were divided into 8 groups of study, consistent with low response to clopidogrel and the type of coronary artery disease. Low response to clopidogrel-defined as adenosine diphosphate test-ADP-test of >46 U by multiple electrode platelet aggregometry was evaluated in correlation with cardiovascular risk factors and biomarkers of oxidative stress, endothelial dysfunction, hypercoagulability, high platelet reactivity. Results: In coronary artery disease, low response to clopidogrel significantly correlated with older than 65 years, smoking, hypertension, diabetes mellitus, body mass index of >25, previous aspirin treatment (P < 0.05), high value of total and low-density lipoprotein cholesterol, low value of high-density lipoprotein cholesterol, low response to aspirin, high mean platelets volume and von Willebrand factor activity, low flow-mediated vasodilatation, total antioxidant status (P < 0.01) and only in patients with SA of male gender (P < 0.01). The incidence of other hypercoagulability biomarkers, such as reduced values of S protein, C protein, antithrombin III, and V Factor Leiden resistance to activated protein C, was very low and not correlated with low response to clopidogrel. Conclusions: In coronary artery disease, low response to clopidogrel significantly correlated with the most of old cardiovascular risk factors, with previous aspirin treatment, low response to aspirin, higher mean platelets volume, higher von Willebrand factor activity, lower flow-mediated vasodilatation, and lower total antioxidant status values and only in patients with SA of male gender.