Platelets
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Platelet dysfunction is an important cause of bleeding early after cardiac surgery. Whole-blood multiple electrode aggregometry (MEA), investigating the adhesion and aggregation of activated platelets onto metal electrodes, has shown correlations with platelet concentrates transfusion in this setting. Platelet activity in vivo is dependent on shear stress, an aspect that cannot be investigated with MEA, but with the cone and plate(let) analyzer (CPA) Impact-R that measures the interaction of platelets and von Willebrand factor (vWF) in whole blood under shear. ⋯ For the Impact-R analysis performed in citrated blood, no correlation with platelet concentrates transfusion was observed. In contrast, MEA was comparable between the groups and correlated significantly with intraoperative platelet concentrates transfusion in both groups (rho between -0.47 and -0.62, p < 0.05). Multiple electrode aggregometry appeared more useful and easier to apply than CPA for preoperatively identifying patients with platelet concentrates transfusion in cardiac surgery.
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Previous investigations in patients with coronary artery disease (CAD) revealed differences in thromboelastographic parameters indicating different states of coagulability. The aim of the present study was to investigate the coagulation status of patients with documented CAD and type II diabetes mellitus (DM) and non-diabetic patients with coronary artery disease with the PFA-100® and the ROTEM®. No differences were found in platelet function as measured with collagen/epinephrine (263.6 ± 70.6 s vs. 254.6 ± 65.3 s) and collagen/ADP cartridges (105.3 ± 63.2 s vs. 90.6 ± 47.3 s) in CAD patients with DM and CAD patients without DM. ⋯ Moreover, a weak trend for higher maximum clot firmness (MCF) was seen in CAD patients with DM compared with CAD patients without DM with the EXTEM reagent (68.1 ± 7.5 vs. 63.6 ± 8.6, p = 0.08) and the INTEM reagent (68.4 ± 7.2 vs. 64.1 ± 8.2, p = 0.09). The ROTEM® analysis indicates increased coagulability in patients with coronary artery disease and diabetes mellitus compared to non-diabetic CAD patients. Moreover, the ROTEM® device seems to be an appropriate and easy-to-use tool to describe the coagulation status in these patients groups.
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"One-stop" hybrid coronary revascularization has emerged to be a reliable and attractive alternative for selected patients with multivessel coronary artery disease. However, the optimal antiplatelet regimen of the one-stop hybrid procedure still remains controversial. We modified the antiplatelet protocol in order to reduce the risk of perioperative bleeding and maximally inhibit platelet activity. ⋯ No major adverse clinical events such as death, perioperative myocardial infarction, stent thrombosis or reoperation for bleeding occurred in both groups within 30 days after procedure. These results demonstrate that our modified antiplatelet therapy can sufficiently inhibit platelet activity similarly as the conventional protocol for PCI early after operation. Thus, this modified protocol, with continuous use of aspirin and intraoperative administration of loading dose clopidogrel, might be a safe and effective antiplatelet strategy for the one-stop hybrid coronary revascularization.
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Insufficient inhibition of platelet function by acetyl salicylic acid (ASA) or other platelet inhibitors is a risk factor for arterial thrombosis in cardiovascular patients. We wanted to collect and analyse information on the frequency and probable causes of non-response to ASA in patients prior to and after cardiac surgery. One hundred and one patients (mean age 68 ± 9 years) undergoing cardiac surgery (98 patients with coronary bypass grafting, 18 cases had combined valve replacement, and three patients with only valve replacement) were enrolled. ⋯ However, in 10 healthy volunteers we did not observe any interference of metamizole with the response to ASA. In conclusion, platelet response to ASA is markedly decreased after cardiac surgery. The underlying mechanisms and the clinical consequences of the post-operative instability of non-response to ASA need further evaluation.