026 Impact of diabetes mellitus on residual platelet reactivity in coronary patients treated by dual antiplatelet therapy with aspirin and clopidogrel

Abstract

Numerous recent studies showed that about 4 to 30% of patients treated with conventional doses of clopidogrel do not display adequate antiplatelet response and then the concept of clopidogrel resistance has arisen. Recently, a number of observations have indicated that patients with diabetes mellitus (DM) exhibit persistent platelet activation and low response after antiplatelet therapy. The purpose of this study was to establish the prevalence and the predictive factors of the resistance to clopidogrel in a coronary artery disease population, using ex vivo measure of platelet aggregation: the cone and platelet analyzer. The population of this prospective study was comprised of 105 patients with acute coronary syndrome. Mean age was 57.8 ± 10.8 years, 81.9% were males, 36,5% patients had history of hypertension, 54,3% patients were diabetic. Patients were given a loading dose of 300-600 mg followed by a maintenance dose of 75 mg on top of a maintenance dose of aspirin ranging from 125 mg to 250 mg. Platelet aggregation was assessed using the Impact R (Diamed®). The degree of platelet adherence was evaluated as a percentage of surface coverage (SC). Residual platelet reactivity was defined as a SC ≤ 2.8%. The mean surface coverage was of 7.78 + 4.29%. We found that 17.1% of our population was clopidogrel resistant. By univariate analysis female sex and diabetes were associated with an increased incidence of clopidogrel resistance, nevertheless, by multivariate analysis, diabetes was the only independent predictive factor, (OR=3.5, IC 952[1.1-11.4]; P=0.0039). The prevalence of clopidogrel resistance was higher in diabetic patients compared to non diabetics (24.6% vs 8.3%; p=0.02) respectively. This prevalence was greater in diabetic patients treated by insulin (30%). Concomitant medication did not influence the incidence of clopidogrel resistance in particular the use of Omeprazol and Atorvastatin. Diabetic patients do not respond well to the available antiplatelet regimen when compared with similar patients without DM. The clinical implications of these findings are unknown but are potentially important.