Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Sep 2012
ReviewUnfractionated heparin for the treatment of venous thromboembolism: best practices and areas of uncertainty.
Nearly 100 years after its discovery, unfractionated heparin (UFH) remains a widely used anticoagulant for the treatment of venous thromboembolism (VTE) and several other thrombotic and prothrombotic conditions. Decades of experience and investigation have contributed to our knowledge of this agent, but crucial questions regarding its optimal use in clinical practice remain unanswered. This review will critically examine the evidence for dosing and laboratory monitoring of UFH in the management of VTE, and highlight areas of uncertainty and future research.
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Semin. Thromb. Hemost. · Jul 2012
ReviewAutoimmune thrombotic microangiopathy: advances in pathogenesis, diagnosis, and management.
Thrombotic microangiopathy, or the syndrome of thrombocytopenia and hemolysis with schistocytes on blood smears, has been a subject of uncertainty and intense controversy. The pathogenesis of thrombotic microangiopathy was unknown and no classification of thrombotic thrombocytopenic purpura and hemolytic uremic syndrome was satisfactory. ⋯ This pathogenesis-based disease classification requires new diagnostic approaches and provides a framework for rational therapeutic designs. This review discusses the new concepts in the pathogenesis, diagnosis, and management of thrombotic microangiopathy, with particular emphasis on the autoimmune causes of ADAMTS-13 deficiency and defective complement regulation.
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Coagulation factor I (fibrinogen) plays an essential role in the hemostatic system by bridging activated platelets and being the key substrate for thrombin in establishing a consolidating fibrin network. Fibrinogen is synthesized in the liver and the plasma concentration is 1 to 5-4.0 g/L. During recent 10 years, fibrinogen has been recognized to play an important role in controlling hemorrhage. ⋯ This article provides a description of the biochemistry and mechanisms of fibrinogen as well as the etiology for developing fibrinogen deficiency. Furthermore, it summarizes laboratory and experimental data on the role of fibrinogen in dilutional coagulopathy and addresses laboratory monitoring issues. Finally, it lists retrospective and prospective studies, which have been designed to assess the clinical efficacy and safety of hemostatic intervention with fibrinogen concentrate.
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Semin. Thromb. Hemost. · Apr 2012
ReviewProhemostatic interventions in trauma: resuscitation-associated coagulopathy, acute traumatic coagulopathy, hemostatic resuscitation, and other hemostatic interventions.
Trauma is the most common cause of death in the young and hemorrhage is the most important cause of death in patients with trauma. Recently redefined pathways of inflammation and coagulation, together with hypothermia and acidosis contribute to trauma-associated coagulopathy and aggravation of bleeding. ⋯ Recombinant factor VIIa, fibrinogen and prothrombin complex concentrates, and antifibrinolytic agents have been evaluated in clinical trials. These interventions show promising effects but their efficacy in reducing clinically important outcome parameters need to be confirmed in clinical studies.
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Surgical procedures of the liver, such as partial liver resections and liver transplantation, are major types of abdominal surgery. Liver surgery can be associated with excessive intraoperative blood loss, not only because the liver is a highly vascularized organ, but also because it plays a central role in the hemostatic system. Intraoperative blood loss and transfusion of blood products have been shown to be negatively associated with postoperative outcome after liver surgery. ⋯ In patients with liver cirrhosis, there is increasing evidence that factors such as portal hypertension and the hyperdynamic circulation play a more important role in the bleeding tendency than changes in the coagulation system. Therefore, intravenous fluid restriction rather than prophylactic administration of large volumes of blood products (i.e., FFP) is recommended in patients undergoing major liver surgery. Pharmacological agents such as antifibrinolytic drugs or recombinant factor VIIa may be indicated in selected individual patients, but these agents do not have a routine role in the management of patients undergoing liver surgery.