Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Apr 2011
ReviewPreventing postsurgical venous thromboembolism: pharmacological approaches.
The use of antithrombotic drugs for the prevention of venous thromboembolism (VTE) in patients undergoing surgery is presently based on solid principles and high-level scientific evidence. This article reviews current strategies of pharmacological thromboprophylaxis. The level of VTE risk following surgery depends on a variety of factors that the surgeon should take into account, including the type of surgery and the presence of additional risk factors, such as elderly age and cancer. ⋯ Patients undergoing major orthopedic surgery have a particularly high risk of VTE, and routine thromboprophylaxis with LMWH, fondaparinux, or a vitamin K antagonist (international normalized ratio target: 2.0 to 3.0) is the standard of care in this group of patients. Recently, two new oral anticoagulants, rivaroxaban (a factor Xa inhibitor) and dabigatran etexilate (a direct thrombin inhibitor) have been licensed to be used for thromboprophylaxis after orthopedic surgery in Europe. Mechanical methods of thromboprophylaxis (compression stockings, intermittent pneumatic compression, vena cava filters), not discussed in detail in this review, should always be considered in patients at high thrombotic risk, in association with the pharmacological strategies, or in cases of contraindications to anticoagulants, as in patients or procedures at high risk of bleeding.
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Sickle cell disease (SCD) is characterized by the presence of sickle hemoglobin, which has the unique property of polymerizing when deoxygenated. The pathophysiology of acute and chronic clinical manifestations of SCD have shown the central role of dense, dehydrated red cells in acute and chronic clinical manifestations of this pathology. ⋯ This review discusses, in the context of SCD, (1) abnormalities in the coagulation system, (2) perturbation of platelet activation and aggregation, (3) vascular endothelial dysfunction, (4) the contribution of cell inflammatory responses, and (5) the connection with nitric oxide metabolism. We also review the available studies on the therapeutic approaches in clinical management of hypercoagulability in SCD.
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Semin. Thromb. Hemost. · Oct 2010
ReviewGlobal hemostasis in pregnancy: are we using thromboelastography to its full potential?
Pregnancy is a unique situation where significant physiological changes in all maternal organ systems take place. Most of these changes return to normal after delivery. During normal pregnancy the hemostatic balance changes in the direction of hypercoagulability, thus decreasing bleeding complications at time of delivery. ⋯ Despite the clear value as a test for monitoring hemostatic status of pregnancy-related complications, TEG is still underused for reasons such as poor awareness regarding the technique and interpretations, lack of full standardization, and the unavailability of large clinical studies. However, the fact remains that TEG is undoubtedly attractive to both researchers and clinicians, particularly in a point-of-care setting. We hope that much more investment is directed to TEG studies in both experimental and clinical fields to improve applications and promote use, especially with respect to clinical decision making in pregnancy-related complications.
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Semin. Thromb. Hemost. · Oct 2010
ReviewCoagulation abnormalities in the trauma patient: the role of point-of-care thromboelastography.
Current recommendations for resuscitation of the critically injured patient are limited by a lack of point-of-care (POC) assessment of coagulation status. Accordingly, the potential exists for indiscriminant blood component administration. Furthermore, although thromboembolic events have been described shortly after injury, the time sequence of post-injury coagulation changes is unknown. ⋯ Thromboelastography (TEG), a time-sensitive dynamic assay of the viscoelastic properties of blood, closely parallels the CBM, permitting timely, goal-directed restoration of hemostasis via POC monitoring of coagulation status. TEG-based therapy allows for goal-directed blood product administration in trauma, with potential avoidance of the complications resulting from overzealous component administration, as well as the ability to monitor post-injury coagulation status and thromboprophylaxis. This overview addresses coagulation status and thromboprophylaxis management in the trauma patient and the emerging role of POC TEG.
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Thromboelastography (TEG) has been used in experimental animal studies since the early 1960s and in a routine clinical setting for the past decade. From the data currently available, it is clear that both the scope and limitations of TEG in animals resemble those observed in humans. ⋯ TEG is often used in animals to monitor the effect of different pro- and anticoagulant drugs and often performs better at this task than conventional coagulation assays. TEG is already well established in veterinary medicine, and with the rapid dissemination of the technique currently taking place, we can expect to see a wide variety of interesting animal data published in the near future.