Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Oct 2010
ReviewQuality assurance and quality control of thrombelastography and rotational Thromboelastometry: the UK NEQAS for blood coagulation experience.
Global hemostasis devices are currently being employed in operating rooms to assess the bleeding risk and outcomes for patients undergoing surgery. Two devices currently available are the TEG (Thromboelastograph; Haemoscope Corp., Niles, IL) and the ROTEM (Rotation Thromboelastometer; Pentapharm GmbH, Munich, Germany). Both measure the speed of clot formation, the strength of the clot when formed, and clot fibrinolysis kinetics. ⋯ The precision of the tests varied greatly for both devices, with coefficients of variances ranging from 7.1 to 39.9% for TEG and 7.0 to 83.6% for ROTEM. Some centers returned results that were sufficiently different from those obtained by other participants to predict alterations in patient management decisions. Our data indicate that regular EQA/proficiency testing is needed for these devices.
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Semin. Thromb. Hemost. · Oct 2010
ReviewStandardization of thromboelastography: values and challenges.
Laboratory evaluation of hemostasis has been performed using plasma for several decades. The cell-based model of coagulation has now led to renewed interest in the global assays of coagulation such as thrombin generation and thromboelastography. These tests have remained as research tools, however, because of the lack of studies to demonstrate their reliability. ⋯ It is therefore critical to standardize the assay to achieve clinical relevance. This article summarizes the TEG-ROTEM Working Group's efforts to try and standardize thromboelastography and the challenges faced in this process. Although this has been the first effort to standardize this test, it is extremely important to continue this work, so that we may investigate the usefulness and possible applications of thromboelastography in evaluating the process of hemostasis.
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Semin. Thromb. Hemost. · Oct 2010
ReviewCritical factors contributing to the thromboelastography trace.
The thromboelastography trace provides a graphical and numerical representation of the viscoelastic changes associated with fibrin polymerization. When used with whole blood, the shape of this trace is a composite of the effects of white and red cell content and composition, platelet number and function, fibrinogen concentration, as well as coagulation protein function and balance. The trace is also influenced by pharmacological agents such as anticoagulants, antiplatelet therapy, and coagulation factor supplementation. ⋯ New applications for pharmaceutical monitoring and patient screening are being explored. This review gives a broad overview of the applications of the technology. In particular it considers the factors that most influence the characteristics of the trace, be they preanalytical, analytical, or clinical.
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Thromboelastography (TEG) has been used in experimental animal studies since the early 1960s and in a routine clinical setting for the past decade. From the data currently available, it is clear that both the scope and limitations of TEG in animals resemble those observed in humans. ⋯ TEG is often used in animals to monitor the effect of different pro- and anticoagulant drugs and often performs better at this task than conventional coagulation assays. TEG is already well established in veterinary medicine, and with the rapid dissemination of the technique currently taking place, we can expect to see a wide variety of interesting animal data published in the near future.
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Semin. Thromb. Hemost. · Jul 2010
ReviewRecombinant anticoagulant factors for adjunctive treatment of sepsis.
Inflammation and coagulation play a pivotal role in the pathogenesis of sepsis. Increasing evidence points to an extensive cross-talk between these two systems, whereby inflammation not only leads to activation of coagulation, but coagulation also considerably affects inflammatory activity. The intricate relationship between inflammation and coagulation has major consequences for the pathogenesis of microvascular failure and subsequent multiple organ failure, as a result of severe infection and the associated systemic inflammatory response. ⋯ Important factors include endothelial-bound anticoagulant mechanisms, such as the antithrombin system, the (activated) protein C/thrombomodulin system, and tissue factor pathway inhibitor, which are all impaired during sepsis. Restoration of these anticoagulant pathways is currently evaluated in several clinical studies. Production of these physiological anticoagulants by recombinant technology greatly facilitates this adjunctive treatment strategy.