Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Jul 2015
ReviewClassical Notions of Coagulation Revisited in Relation with Blood Losses, Transfusion Rate for 700 Consecutive Liver Transplantations.
During the last decade, improved surgical and anesthetic management, such as better understanding of coagulation defects and the use of the phlebotomy, has reduced intraoperative blood product transfusions during orthotopic liver transplantation (OLT). The goal of this study was to look at the impact of initial conventional coagulation tests on blood loss and blood product requirement and to evaluate the role of the phlebotomy during liver transplantations. A total of 700 consecutive OLTs were studied. ⋯ Phlebotomy was linked to decrease in blood loss, RBC transfusions, and increased survival rate. It is concluded that bleeding did not correlate with traditional coagulation defects or the severity of recipient's disease. Preemptive phlebotomy was linked to a decreased blood loss, a decreased transfusion rate, and an increased 1-year survival rate.
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Semin. Thromb. Hemost. · Jul 2015
ReviewClinical Utility of Viscoelastic Tests of Coagulation (TEG/ROTEM) in Patients with Liver Disease and during Liver Transplantation.
The concept that patients with stable liver disease are at an increased risk of bleeding, based solely on abnormalities of conventional coagulation tests such as prothrombin time (PT) and international normalized ratio (INR), is now recognized to be an overly simplistic interpretation of an extremely complex situation. These tests are in fact very poor predictors of bleeding in patients with liver disease who undergo invasive or surgical procedures. Commercially available whole blood viscoelastic tests (thromboelastography [TEG] and thromboelastometry [ROTEM]) evaluate the kinetics of coagulation from initial clot formation to final clot strength. ⋯ Despite prolonged PT/INR and low platelet counts, viscoelastic tests are within normal range in many patients with both acute and chronic liver disease, commensurate with the concept of rebalanced hemostasis, and in keeping with the fact that an increasing number of these patients undergo liver transplantation without the need for blood or blood products. In addition, these tests reveal important additional information, such as the presence of hypercoagulability and a prothrombotic state, and also information about the presence of endogenous heparinoids associated with vascular endothelial damage, due to sepsis or acute inflammation. This review provides an overview of the current literature on the potential clinical utility of viscoelastic tests of coagulation in patients with liver disease.
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Semin. Thromb. Hemost. · Apr 2015
Comparative StudyInternational normalized ratio monitoring of vitamin K antagonist therapy: comparative performance of point-of-care and laboratory-derived testing.
The monitoring of warfarin therapy using the international normalized ratio (INR) has now moved outside the laboratory's control by use of point-of-care (POC) devices. Although this provides patients with the convenience of immediate results and clinical assessment, POC-INRs are often performed by nonlaboratory staff with little experience in quality control. The Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP) Haematology has devised a POC-INR external quality assessment (EQA) program that is suitable for both laboratory and nonlaboratory operators (e.g., nurses) to perform INR testing with good accuracy and precision. ⋯ A comparative assessment with other EQA providers showed agreement and disparity with our data in terms of comparative CVs obtained between the laboratory and POC-INRs. The growth of the RCPAQAP POC-INR program from 29 to 360 in the past 12 years highlights the importance of providing suitable EQA for POC-INR staff who are unfamiliar with laboratory practice. This helps maintaining consistent results, which have important implications for the therapeutic management of patients on vitamin K antagonist therapy.
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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.