Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Mar 2015
Review Comparative StudyComparative efficacy and safety of the non-vitamin K antagonist oral anticoagulants for patients with nonvalvular atrial fibrillation.
The non-vitamin K antagonist oral anticoagulants (NOACs), such as the thrombin inhibitor (dabigatran) and the direct factor Xa inhibitors (rivaroxaban, apixaban, and edoxaban), have been shown to be at least as efficacious and safe as conventional oral anticoagulants, such as the vitamin K antagonists (VKAs) (e.g., warfarin), for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). Each NOAC has various advantages and specific features, and therefore decisions regarding appropriate stroke prevention require individual assessment of stroke and bleeding risk on anticoagulation with VKA therapy and NOACs when starting on any of these drugs. This review briefly describes the results of the four NOACs clinical randomized trials and discusses how they might impact clinical practice and choice of anticoagulants in atrial fibrillation patients. Moreover, this review discusses the differences of the proposed management of antithrombotic therapy in several international guidelines and pragmatic issues of NOACs for stroke prophylaxis.
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Semin. Thromb. Hemost. · Feb 2015
ReviewHypercoagulability and venous thromboembolism in burn patients.
To our knowledge, this is the first comprehensive review on the subject of venous thromboembolism (VTE) and hypercoagulability in burn patients. Specific changes in coagulability are reviewed using data from thromboelastography and other techniques. ⋯ The incidence and risk factors associated with VTE in burn patients are then examined, followed by the use of low-molecular-weight heparin thromboprophylaxis and monitoring techniques using antifactor Xa levels. The need for large, prospective trials in burn patients is highlighted, especially in the areas of VTE incidence and safe, effective thromboprophylaxis.
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Hemostasis and thrombosis in trauma patients consist of physiological hemostasis for wound healing and the pathological reaction of disseminated intravascular coagulation (DIC). Whole body trauma, isolated brain injury, and fat embolism syndrome, if extremely severe, can cause DIC and affect a patient's prognosis. Shock-induced hyperfibrinolysis causes DIC with the fibrinolytic phenotype, contributing to oozing-type severe bleeding. ⋯ Another type of pathological hemostatic change is acute coagulopathy of trauma shock (ACOTS), which gives rise to activated protein C-mediated systemic hypocoagulation, resulting in bleeding. ACOTS occurs only in trauma associated with shock-induced hypoperfusion and there is nothing to suggest DIC in this phenomenon. This review will provide information about the recent advances in hemostasis and thrombosis in trauma and will clarify the pathogeneses of the pathological processes observed in trauma patients.
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Semin. Thromb. Hemost. · Feb 2015
ReviewVenous thromboembolism prophylaxis in critically ill patients.
Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is recognized as a common complication in critically ill patients. Risk factors including critical illness, mechanical ventilation, sedative medications, and central venous catheter insertion are major contributing factors to the high risk of VTE. Because of their impaired cardiopulmonary reserve, PE arising from thrombosis in the deep veins of the calf that propagates proximally is poorly tolerated by critically ill patients. ⋯ As a result, over the past decades, VTE prophylaxis had become a standard of preventive measure in the intensive care unit (ICU). In clinical practice, the rate of VTE prophylaxis varies and may be inadequate in some centers. A perception of a high bleeding risk in critically ill patients is a major concern for most physicians that may lead to inadequate prophylaxis.
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Semin. Thromb. Hemost. · Feb 2015
ReviewHeparin-induced thrombocytopenia in critically ill patients.
Many critically ill patients receive heparin, either before intensive care unit (ICU) admission (e.g., postcardiac surgery), for prophylaxis/treatment of thrombosis, for hemodialysis/filtration, or even incidentally (e.g., flushing of intravascular catheters), and are therefore at risk for developing immune heparin-induced thrombocytopenia (HIT), a prothrombotic drug reaction caused by platelet-activating antiplatelet factor 4 (PF4)/heparin antibodies. However, HIT explains at most 1 in 100 thrombocytopenic ICU patients (HIT frequency 0.3-0.5% vs. 30-50% background frequency of ICU-associated thrombocytopenia), and most patients who form anti-PF4/heparin antibodies do not develop HIT; hence, HIT overdiagnosis often occurs. This review discusses HIT-related issues relevant to ICU patients, including how to (1) distinguish HIT both clinically and serologically from non-HIT-related thrombocytopenia; (2) recognize HIT-mimicking disorders, such as the acute disseminated intravascular coagulation (DIC)/liver necrosis-limb necrosis syndrome; (3) prevent HIT in the ICU through use of low-molecular-weight heparin; and (4) treat HIT, including awareness of "PTT confounding" when anticoagulating patients with DIC.