Thrombosis research
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Thrombosis research · Oct 2012
Should we follow the 9th ACCP guidelines for VTE prevention in surgical patients?
The 9th edition of the American College of Chest Physicians (ACCP) guidelines on antithrombotic therapy and prevention, includes relevant changes compared to previous versions. In the 9th ACCP, leadership of most chapters was given to methodologists who were familiar with the GRADE methodology. All topic panelists underwent a selection process paying particular attention to their financial and intellectual conflicts of interests. ⋯ A controversial modification in orthopedic patients is recommendation in favor of the use of aspirin after hip or knee arthroplasty. New oral anticoagulants are recommended, but LMWH are suggested as the preferred option. Extending pharmacological prophylaxis for up to 35days rather than 10-14days is now suggested for patients undergoing major orthopedic surgery.
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Thrombosis research · Oct 2012
Critical role of factors II and X during coumarin anticoagulation and their combined measurement with a new Fiix-prothrombin time.
Vitamin K antagonists (VKA) are monitored with prothrombin time (PT) based assays that are equally sensitive to reductions in factors II, VII or X. We compared the effect of vitamin K dependent (VKD) coagulation factors on PT and also on rotational thromboelastometric (ROTEM) parameters. The PT was equally sensitive to reductions in factors II, VII or X but ROTEM parameters correlated poorly with the PT in anticoagulated patients´ plasmas. ⋯ The ROTEM results suggest that mild to moderate reductions in factors II or X are more important during clot formation than factors VII or IX. Reductions in FII and X may better reflect anticoagulation with VKA than FVII or IX. The new Fiix-PT may more accurately reflect the degree of therapeutic anticoagulation in patients treated with VKA than the current PT which is subject to a confounding variation caused by FVII.
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Thrombosis research · Oct 2012
Do new oral anticoagulants require laboratory monitoring? The clinician point of view.
Although no laboratory monitoring is needed for new anticoagulants, the measurement of their activity is required in special clinical situations. Standardised tests have been developed for rivaroxaban and dabigatran which allow the measurement of the patient's response to the drug at Cmax (2 to 3 hours after intake) or at trough (before repeated administration). The results can be expressed in mg per ml of plasma and compared to the expected concentrations. ⋯ These observations raise the question regarding the potential benefit of laboratory coagulation monitoring from time to time. Trials are needed to determine the relationship of assay results with bleeding or thrombotic complications. Pros and Cons laboratory measurements are discussed.
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Thrombosis research · Oct 2012
ReviewMicroparticles in vascular disorders: how tissue factor-exposing vesicles contribute to pathology and physiology.
Coagulation is initiated by tissue factor (TF). Coagulant TF is constitutively expressed by extravascular cells, but there is increasing evidence that TF can also be present within the blood, in particular during pathological conditions. ⋯ Remarkably, high levels of coagulant TF-exposing vesicles are present in other body fluids such as saliva and urine of healthy persons, suggesting that these vesicles play a physiological role. We postulate that the presence of TF-exposing vesicles in body fluids as saliva and urine provides an additional source of coagulant TF that promotes coagulation, thereby reducing blood loss and contributing to host defence by reducing the risk of microorganisms entering the "milieu intérieur".