Thrombosis research
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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
Evaluation of ticagrelor pharmacodynamic interactions with reversibly binding or non-reversibly binding P2Y(12) antagonists in an ex-vivo canine model.
As ticagrelor, clopidogrel and cangrelor therapies may be used in the same clinical setting, their potential pharmacodynamic interactions are of interest. Hence, we investigated possible interactions between these agents in dogs using a variety of switching protocols. ⋯ The extent of the pharmacodynamic drug-drug interactions observed between clopidogrel and cangrelor or ticagrelor apparently depends on the level of receptor occupancy when clopidogrel is administered. Importantly, no significant pharmacodynamic interaction occurred between ticagrelor/clopidogrel when clopidogrel was given at clinical trough IPA levels with ticagrelor. No significant pharmacodynamic interaction occurred with cangrelor and ticagrelor.
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Thrombosis research · Oct 2012
Antithrombotic agents and invasive procedures--hematologist point of view.
The management of a patient treated with an antithrombotic agent who requires an invasive procedure remains challenging. There are antidotes neither for the antiplatelet agents nor the new anticoagulants. A good knowledge of basic pharmacology of these drugs and the help of a hematologist within a multidisciplinary approach are essential. The potential interest of laboratory tests and the use of reversal agents, and the transfusion of plasma and platelets will be discussed.