OBJECTIVE-Diabetic patients may have a higher prevalence of platelet aspirin resistance than nondiabetic patients. Our goal was to analyze platelet aspirin responsiveness to various aspirin doses in diabetic and nondiabetic patients. RESEARCH DESIGN AND METHODS-We examined the effect of aspirin (81, 162, and 325 mg/day for 4 weeks each) on platelet aspirin responsiveness in 120 stable outpatients (30 diabetic patients and 90 nondiabetic patients) with coronary artery disease (CAD) using light transmittance aggregometry (LTA), VerifyNow, platelet function analyzer (PFA)-100, and levels of urinary 11-dehydro-thromboxane B 2 (11-dh-TxB 2 ).RESULTS-In the total group, a low prevalence (0 -2%) of aspirin resistance was observed with all aspirin doses as determined by arachidonic acid-induced LTA. Aspirin resistance was higher at the 81-mg dose in diabetic versus nondiabetic patients using collagen-induced LTA (27 vs. 4%, P ϭ 0.001), VerifyNow (13 vs. 3%, P ϭ 0.05), and urinary 11-dh-TxB 2 (37 vs. 17%, P ϭ 0.03). Diabetic patients treated with 81 mg exhibited higher platelet function measured by VerifyNow, collagen-and ADP-induced LTA, and 11-dh-TxB 2 levels (P Յ 0.02 for all comparisons). Higher aspirin doses significantly inhibited platelet function and decreased aspirin resistance in diabetic patients (P Ͻ 0.05).CONCLUSIONS-Diabetic patients with CAD treated with 81 mg aspirin exhibit a higher prevalence of aspirin resistance and have significantly higher ADP-and collagen-induced platelet aggregation, 11-dh-TxB 2 levels, and aspirin reaction units measured by VerifyNow than nondiabetic patients. Increased aspirin dosing resulted in similar rates of resistance and platelet function levels between groups. These findings indicate that diabetic patients exhibit a global high platelet reactivity phenotype that may be partially overcome by higher aspirin doses. Diabetes 56: 3014-3019, 2007

One week of DC ingestion improved lipid profiles and decreased platelet reactivity within the total group while reducing inflammation only in women. Regular dark chocolate ingestion may have cardioprotective properties. Further long-term research is warranted to evaluate the effect of flavonoids on cardiovascular health and to determine whether DC's beneficial effects are related to flavonoids or some yet unknown component. This research is based on a larger study which was presented at the American Heart Association Scientific Sessions 2007.

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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.