Abstract 4017: Reduced Anti-Platelet Response to Clopidogrel in Diabetic Patients Undergoing Percutaneous Coronary Intervention

Despite dual antiplatelet therapy with aspirin and clopidogrel, patients with diabetes mellitus (DM) suffer from frequent recurrent ischemic events. Previous studies have shown that DM patients have a higher prevalence of aspirin resistance than non-DM patients. The aim of this analysis was to determine if DM patients have a decreased antiplatelet response to either maintenance or high loading clopidogrel administration when compared to non-DM patients. One hundred and thirty eight patients that underwent percutaneous coronary intervention (PCI) in the Clear Platelets-2 Study were included in this analysis. Patients were grouped according to clopidogrel dose use and presence of DM. Subjects were either on maintenance therapy with 75mg of clopidogrel (C75 group; n=72) or received a loading dose of 600mg of clopidogrel immediately after PCI (C600 group; n=66). All patients received 325-mg aspirin. Platelet function was measured by Light Transmission Aggregometry using ADP (5 and 20μM), TRAP (15 μM), and collagen (2μg/ml). Overall, DM patients in the C75 group had higher platelet aggregation using 5 and 20μM ADP and 2μg/ml collagen. DM patients had lower relative platelet inhibition at 24hrs with 5 μM ADP and 2μg/ml collagen in the C600 group when compared to non-DM patients (Table ). DM patients undergoing PCI exhibit higher platelet aggregation when receiving standard clopidogrel maintenance dose and lower relative platelet inhibition with high clopidogrel loading dose. Higher doses of clopidogrel or more potent P2Y12 receptor antagonists may be needed in DM patients to obtain comparable platelet inhibition to non-DM patients.