Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Jul 2007
Review Comparative StudyPreclinical and clinical characteristics of rivaroxaban: a novel, oral, direct factor Xa inhibitor.
There are several novel anticoagulants in development that target factor Xa(FXa)-the pivotal point of the coagulation cascade. One promising agent is rivaroxaban (a highly selective, oral, direct FXa inhibitor), which is in advanced clinical development for the prevention and treatment of thromboembolic disorders. Oral rivaroxaban may be given in fixed once-daily doses, with the potential for no coagulation monitoring. ⋯ Phase II studies of rivaroxaban for the prevention of venous thromboembolism (VTE) after major orthopedic surgery support these findings. The results also suggested that a total daily dose range of 5 to 20 mg rivaroxaban had similar efficacy and safety to enoxaparin, and that 10 mg rivaroxaban once daily was the optimal dose. This review assesses the preclinical and clinical characteristics of rivaroxaban, and discusses phase II findings with rivaroxaban for the prevention of VTE after major orthopedic surgery.
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Semin. Thromb. Hemost. · Jul 2007
ReviewAntimetastatic activities of modified heparins: selectin inhibition by heparin attenuates metastasis.
Heparin, which is traditionally used as an anticoagulant but has a variety of additional biological activities, was shown in several retrospective and prospective clinical trials to have an effect on cancer survival. Experimental evidence from animal models consistently demonstrates that heparin is an efficient inhibitor of metastasis. To clarify the mechanism of heparin antimetastatic activity, several biological effects are being investigated. ⋯ Modified heparins characterized for heparanase inhibitory activity are also potential inhibitors of selectins. Selectin inhibition is a clear component of heparin inhibition of metastasis. The contribution of selectin or heparanase inhibition by heparin can provide evidence about its antimetastatic activity.
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Semin. Thromb. Hemost. · Jun 2007
ReviewManagement of bleeding complications of hematologic malignancies.
Persons with hematologic malignancies bleed for a variety of reasons, including alterations in platelet function and numbers, clotting factor deficiencies, circulating anticoagulants, and defects in vascular integrity. The management of bleeding begins with a full characterization of the hemostatic defect. Vitamin K deficiency always should be considered and excluded by clinical history and laboratory tests. ⋯ Fresh frozen plasma is indicated infrequently; bleeding due to coagulopathies is better managed with cryoprecipitate if fibrinogen is low, or with clotting factor concentrates appropriate for the specific clotting factors found to be deficient. rFVIIa or activated prothrombin complex concentrate usually controls hemorrhage due to autoantibodies directed against factor VIII, and acquired von Willebrand's disease may be responsive to desmopressin or intravenous gamma globulin infusion. Antifibrinolytic agents often enhance other hemostatic therapies, but should be withheld if there is genitourinary bleeding or evidence of disseminated intravascular coagulation. Finally, plasmapheresis and immunoadsorption to remove paraproteins may be helpful when other measures fail to curb bleeding.
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Semin. Thromb. Hemost. · Apr 2007
ReviewEmerging technologies in hemostasis diagnostics: a report from the Australasian Society of Thrombosis and Haemostasis Emerging Technologies Group.
Technology in hemostasis laboratories has evolved enormously during the last 30 years. Although many scientists and clinicians will remember the traditional tilt-tube techniques to screen for coagulation abnormalities and to monitor anticoagulant therapy, the hemostasis laboratory today uses a variety of modern technologies. ⋯ Although these advances in technology have resulted in greater capability, productivity, sensitivity, specificity, and ultimately, improvement in the clinical care of patients, controversies and limitations remain. This article highlights new and emerging technologies in hemostasis and discusses whether they have improved or are likely to improve laboratory diagnostics by specifically addressing the following: (1) Can new technologies help predict likelihood of thrombosis recurrence? (2) Has an understanding of the role of A Disintegrin-like And Metalloprotease with Thrombo Spondin type 1 motifs (ADAMTS13) in microangiopathy resulted in improved diagnostic methods for this disorder? (3) Does thrombelastography allow better definition of bleeding risk than conventional hemostasis assays, especially in settings of acute hemostatic pathology?
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Acute pulmonary embolism (PE) is a potentially life-threatening condition, with an overall 3-month mortality rate of 15% and with right ventricular failure as the most common cause of early death. Risk stratification facilitates identification of high-risk patients and may be helpful in guiding the initial and long-term management. In patients with massive PE and hemodynamic instability, rapid risk assessment is paramount and bedside echocardiography and multislice chest computed tomography (CT) are useful for identifying patients who may benefit from thrombolysis or embolectomy. ⋯ Multislice chest CT is not only useful to diagnose or exclude PE; it also is useful for risk assessment. A right-to-left ventricular dimension ratio > 0.9 on the reconstructed CT four-chamber view identifies patients at increased risk of early death. This article focuses on risk stratification tools, including the clinical examination, electrocardiography, echocardiography, cardiac biomarkers, and chest CT.