Thrombosis research
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Thrombosis research · Aug 2015
The impact of thrombin generation and rotation thromboelastometry on assessment of severity of factor XI deficiency.
The phenotype of bleeding in patients with severe FXI deficiency is unpredictable and unlike other bleeding disorders, it is not directly correlated with levels of FXI. In this study we analyzed whether the global coagulation assays can serve as a clinical tool in predicting bleeding tendency in patients with severe FXI deficiency undergoing surgery, taking into account the large inter-individual variability of FXI levels and genotypes. Thrombin generation (TG) was measured in 39 platelet-poor plasma with or without tissue factor (TF) and in the presence or absence of corn trypsin inhibitor (CTI). ⋯ ROTEM assays failed to distinguish bleeding from non-bleeding patients but could do so between different FXI activity levels and genotypes. In conclusion, in the current study we found a sensitive tool to distinguish between bleeding and non-bleeding patients. In order to recommend TG as a predictive tool for treatment tailoring, a larger patient group is required.
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Thrombosis research · Jul 2015
Clinical evaluation of laboratory methods to monitor apixaban treatment in patients with atrial fibrillation.
The direct factor-Xa inhibitor apixaban is approved e.g. for the prevention of stroke in patients with atrial fibrillation (AF). Although routine monitoring of apixaban therapy is currently not recommended, selective monitoring could be useful to optimize efficacy and safety in certain clinical situations. We studied the exposure and effect of apixaban using different laboratory methods in a clinical setting with a well-defined cohort of AF patients. ⋯ Anti-FXa-assay performed well upon apixaban concentrations in a normal exposure range. Still LC-MS/MS remains the "gold standard" method, covering also low concentrations. Compared to clinical trials, we observed relatively lower apixaban exposure and a more pronounced difference between high and low dose. Additional information regarding apixaban exposure and benefit-risk profile is needed in order to individualize treatment.
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Thrombosis research · Jul 2015
Suppression of plasminogen activator inhibitor-1 by inhaled nitric oxide attenuates the adverse effects of hyperoxia in a rat model of acute lung injury.
Locally increased expression of plasminogen activator inhibitor-1 (PAI-1) in acute lung injury (ALI) is largely responsible for fibrin deposition in the alveolae and lung microvasculature. In vitro, nitric oxide (NO) effectively suppresses the ischemic induction of PAI-1. We aimed to investigate the effects of inhaled NO on PAI-1 expression in ALI in a rat model with and without hyperoxia. ⋯ Inhaled NO can suppress elevated PAI-1 expression in rats with ALI induced by endotoxin. Although exposure to high-concentration oxygen prolongs the duration of PAI-1 mRNA overexpression in ALI, inhaled NO can reduce this effect and alleviate both fibrin deposition and lung injury.
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Thrombosis research · Jul 2015
Multicenter Study Observational StudyPre-procedural dual antiplatelet therapy and bleeding events following transcatheter aortic valve implantation (TAVI).
Transcatheter aortic valve implantation (TAVI) is associated with bleeding that increases mortality. Dual antiplatelet therapy (DAPT) is recommended in TAVI, however little is known about pre-procedural DAPT use and its impact on hemostasis. We sought to determine the frequency, predictors and bleeding events in patients receiving DAPT before TAVI. ⋯ Pre-procedural DAPT is frequent and does not increase short-term bleeding complications or need for transfusion following TAVI. Possible impact of DAPT use before TAVI on ischemic complications needs to be investigated in larger populations.
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Thrombosis research · Jul 2015
ReviewDirect Oral Anticoagulants (DOACs) in the Laboratory: 2015 Review.
Direct oral anticoagulant therapies, including direct anti-Xa and thrombin inhibitors have recently been introduced and may have advantages over vitamin K antagonists such as warfarin. This review describes briefly the clinical utility and mechanism of action of these agents. Detailed information is provided on effect of these agents on routine assays including the APTT and PT as well as their impact on specialty laboratory assays. Also included are the use of drug specific assays and a discussion of alternative methods to determine relative drug concentration, such as evaluating drug calibrators in APTT and PT assays and using heparin calibrated anti-Xa assays to measure direct Xa inhibitors.