Journal of thrombosis and haemostasis : JTH
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J. Thromb. Haemost. · May 2011
Effects of in vitro adult platelet transfusions on neonatal hemostasis.
Thrombocytopenia is frequent among neonates, and 20-25% of affected infants are treated with platelet transfusions. These are frequently given for mild thrombocytopenia (platelets: 50-100 × 10(9) L(-1)), largely because of the known hyporeactivity of neonatal platelets. In tests of primary hemostasis, however, neonates have shorter bleeding and closure times (CTs) than adults. This has been attributed to their higher hematocrits, higher von Willebrand factor (VWF) concentrations, and predominance of longer VWF polymers. ⋯ In vitro'transfusion' of adult platelets into neonatal blood results in shorter CTs than 'transfusion' with neonatal platelets. Our findings should raise awareness of the differences between the neonatal and adult hemostatic system and the potential 'developmental mismatch' associated with platelet transfusions for neonatal hemostasis.
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J. Thromb. Haemost. · May 2011
Decreased active von Willebrand factor level owing to shear stress in aortic stenosis patients.
Aortic stenosis patients often show bleeding complications. Previously, a prolonged platelet function analyzer (PFA-100) closure time was observed with plasma of severe aortic stenosis patients. To elucidate a possible role of circulating preactivated von Willebrand factor (VWF), we determined the level of VWF in its active, platelet-binding conformation in plasma of patients with aortic stenosis. ⋯ Our data demonstrate that the aortic pressure gradient is inversely associated with VWF activation factor, but not with VWF antigen or VWF multimerization in patients with aortic stenosis. These findings might have implications for the bleeding observed in patients with aortic stenosis.
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J. Thromb. Haemost. · Mar 2011
Meta Analysis Comparative StudyIndividual patient data meta-analysis of enoxaparin vs. unfractionated heparin for venous thromboembolism prevention in medical patients.
Unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) are both recommended for venous thromboembolism (VTE) prophylaxis in hospitalized medical patients. ⋯ Enoxaparin significantly reduces VTE in hospitalized medical patients, compared with UFH, without increasing the risk for major bleeding, and was associated with a trend towards reduced all-cause mortality.
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J. Thromb. Haemost. · Mar 2011
Prophylaxis with low-dose low-molecular-weight heparin during pregnancy and postpartum: is it effective?
The optimal approach for venous thrombosis (VTE) prophylaxis during pregnancy and postpartum in women with an increased risk of VTE is not established. ⋯ Although prophylaxis with low-dose LMWH during pregnancy and postpartum proved to be safe, the risk of pregnancy-related VTE is considerable in women with a high risk of VTE. VTE prophylaxis with low-dose LMWH may not be sufficiently effective in these women.