Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Jul 2008
ReviewPoint of care coagulation tests in critically ill patients.
Point of care assays for various analytes have been established in critical care, including blood gas analysis, glucose, electrolytes, and markers for cardiac ischemia. Coagulation assays can also be adapted to the critical care environment by using whole blood as sample material and instruments optimized for point of care analysis. ⋯ Point of care coagulation assays help in rapidly establishing a diagnosis, clarifying causes of bleeding, and monitoring therapy. Thrombelastography and similar assays extend the scope of coagulation diagnostics by visualizing the process of clot formation and extending the observation period to provide an estimate of clot stability versus mechanical and proteolytic attack.
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Semin. Thromb. Hemost. · Jul 2008
ReviewThe role of natural anticoagulants in the pathogenesis and management of systemic activation of coagulation and inflammation in critically ill patients.
Critically ill patients often have systemic activation of both inflammatory systems and coagulation. Increasing evidence points to an extensive cross-talk between these two systems, whereby inflammation leads to activation of coagulation and coagulation considerably affects inflammatory activity. The intricate relationship between inflammation and coagulation may have 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. ⋯ Activated coagulation proteases, such as the tissue factor-factor VIIa complex, factor Xa, and thrombin, can bind to protease-activated receptors on various cells, and the ensuing intracellular signaling leads to increased production of proinflammatory cytokines and chemokines. Activated protein C can bind to the protein C receptor on endothelial cells and mononuclear cells, thereby affecting NF-kappaB nuclear translocation and subsequently influencing inflammatory gene expression and inhibition of tissue factor expression on mononuclear cells. Observations in experimental models of targeted disruption of the protein C gene and restoration of the downregulated protein C pathway by administration of recombinant activated protein C support this notion.
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Semin. Thromb. Hemost. · Apr 2008
ReviewMorbidity and mortality in the catastrophic antiphospholipid syndrome: pathophysiology, causes of death, and prognostic factors.
The catastrophic variant of the antiphospholipid syndrome (APS) is a condition characterized by multiple vascular occlusive events, usually affecting small vessels and evolving over a short period of time, together with laboratory confirmation of the presence of antiphospholipid antibodies. The pathogenesis of catastrophic APS is not completely understood. ⋯ Cerebral involvement has been identified as the main cause of death, being present in one third of patients, and consisting mainly of stroke, cerebral hemorrhage and encephalopathy, followed by cardiac involvement and infection. The only identified prognostic factor for a higher mortality rate is the presence of systemic lupus erythematosus.
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Semin. Thromb. Hemost. · Feb 2008
ReviewCurrent and future prospects for anticoagulant therapy: inhibitors of factor Xa and factor IIa.
Indirect systemic and direct oral factor Xa and direct oral factor IIa inhibitors with improved pharmacologic profiles compared with heparins and vitamin K antagonists are currently in clinical development. This overview focuses on the indirect antithrombin dependent pentasaccharide derivatives of idraparinux and on the most advanced oral direct inhibitors to factor Xa (rivaroxaban and apixaban) and IIa (dabigatran). Specifically, the results of dose-finding studies for the prevention of venous thromboembolism after elective orthopedic surgery, the results of dose-finding studies for treatment of acute venous thromboembolism including prolonged prophylaxis of recurrent events, and the designs of ongoing clinical trials are reviewed.
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Semin. Thromb. Hemost. · Feb 2008
ReviewSurvival of heparins, oral anticoagulants, and aspirin after the year 2010.
The conventional management of thrombotic and cardiovascular disorders is based on the use of heparin, oral anticoagulants, and aspirin. Despite remarkable progress in life sciences, these drugs still remain a challenge and a mystery to us, and their use is far from optimized. The development of low-molecular-weight heparins and the synthesis of heparinomimetics, such as the chemically synthesized pentasaccharide, represent a refined use of heparin. ⋯ Though clinically effective, recent results have prompted a closure of a large clinical trial with prasugrel due to bleeding. The newer anticoagulant and antiplatelet drugs are attractive for several reasons; however, none of these are expected to replace the conventional drugs in polytherapeutic approaches. Heparins, warfarin, and aspirin will continue to play a major role in the management of thrombotic and cardiovascular disorders beyond 2010.