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Aims: In patients with non-ST-elevation acute coronary syndromes (NSTE-ACS) treated with PCI, high (H) platelet reactivity (PR) significantly affects one-year outcome. The aim of this report was to analyse the relationships between HPR, the SYNTAX score (SS) and one-year major adverse cardiac events (MACE: cardiac death, myocardial infarction, stent thrombosis) according to diabetes mellitus (DM) status in patients included in the GEne Polymorphism, Platelet REactivity, and the Syntax Score (GEPRESS) study., Methods and Results: PR was measured using the vasodilator-stimulated phosphoprotein (VASP) assay at three time points (before PCI, at hospital discharge and at one month after PCI), with HPR defined as >50% PR index in 1,042 patients treated with aspirin and clopidogrel for one year after PCI. Patients with DM and an SS ≥15 had the highest MACE rate between one month and one year, further increased by the presence of HPR (16.4%). On the other hand, among all patients with an SS <15, MACE rates remained low (<3%), irrespective of DM status and PR., Conclusions: Among NSTE-ACS patients treated with PCI, the combination of DM, an SS ≥15 and HPR characterised a cohort with the highest MACE rate from one month to one year. In such high-risk patients, careful clinical monitoring and implementation of secondary prevention measures, including the use of potent P2Y12 inhibitors, are strongly advised.

Introduction: Although ruptured atherosclerotic plaques have been extensively analyzed, the composition of thrombi causing arterial occlusion in patients with ST-segment elevation acute myocardial infarction has been less thoroughly investigated. We sought to investigate whether coagulant active tissue factor can be retrieved in thrombi of patients with STEMI undergoing primary percutaneous coronary intervention., Methods: Nineteen patients with ST-segment elevation acute myocardial infarction referred for primary percutaneous coronary intervention were enrolled in this study. Coronary thrombi aspirated from coronary arteries were routinely processed for paraffin embedding and histological evaluation (4 patients) or immediately snap frozen for evaluation of tissue factor activity using a modified aPTT test (15 patients). Immunoprecipitation followed by immunoblotting was also performed in 12 patients., Results: Thrombi aspirated from coronary arteries showed large and irregular areas of tissue factor staining within platelet aggregates, and in close contact with inflammatory cells. Some platelet aggregates stained positive for tissue factor, whereas others did not. Monocytes consistently stained strongly for tissue factor, neutrophils had a more variable and irregular tissue factor staining, and red blood cells did not demonstrate staining for tissue factor. Median clotting time of plasma samples containing homogenized thrombi incubated with a monoclonal antibody that specifically inhibits tissue factor-mediated coagulation activity (mAb 5G9) were significantly longer than their respective controls (88.9 seconds versus 76.5 seconds, respectively; p<0.001). Tissue factor was also identified by immunoprecipitation in 10 patients, with significant variability among band intensities., Conclusions: Active tissue factor is present in coronary artery thrombi of patients with ST-segment elevation acute myocardial infarction, suggesting that it contributes to activate the coagulation cascade ensuing in coronary thrombosis.

Introduction: The antiplatelet effect of standard or increased clopidogrel doses in patients with ST- segment elevation acute myocardial infarction (STEMI) has never been studied. In this study we compared the antiplatelet effect of a 75 mg daily maintenance dose of clopidogrel with 150 mg in patients with STEMI undergoing primary percutaneous coronary intervention (PCI)., Materials and Methods: Fifty-four patients with STEMI undergoing PCI were randomly allocated to receive either 75 mg/day clopidogrel (group 1) or 150 mg/day (group 2) for 1 month. Platelet function, measured by 5 different assays, was determined at 3 time points: 38+/-8 hours after the procedure, 1 week and 1 month after randomization., Results: In group 1, mean +/- SD platelet reactivity index (PRI) measured with the VASP assay was 57.7+/-15.7% and 46.9+/-15.7% at 1 week and 1 month, respectively, compared to 38.8+/-15.7% and 34.9+/-12.6% in group 2 (p=0.0001). Same results were observed for light transmittance aggregometry, whole blood aggregometry and VerifyNow, but not for thromboelastometry. In contrast to what may be expected, the 75 mg daily maintenance dose took longer than 1-week to provide the full clopidogrel antiplatelet effect. Furthermore, patients in group 2 had a nearly 50% reduction in C-reactive protein levels both at 1 week and 1 month., Conclusion: In patients with STEMI and poor responsiveness to clopidogrel a 150 mg daily maintenance dose of clopidogrel is associated with a significant reduction of platelet aggregation and a trend towards reduced inflammation., ((c) 2009 Elsevier Ltd. All rights reserved.)