Volume 152, Issue 6 pp. 758-765
research paper

Effects on fibrin network porosity of anticoagulants with different modes of action and reversal by activated coagulation factor concentrate*

Margareta Blombäck

Margareta Blombäck

Department of Molecular Medicine and Surgery/Coagulation Research

Department of Clinical Sciences/Cardiology

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Shu He

Shu He

Department of Molecular Medicine and Surgery/Coagulation Research

Department of Clinical Sciences/Cardiology

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Niklas Bark

Niklas Bark

Department of Molecular Medicine and Surgery/Coagulation Research

Department of Clinical Neuroscience, Karolinska Institutet, Stockholm

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Håkan N. Wallen

Håkan N. Wallen

Department of Clinical Sciences/Cardiology

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Margareta Elg

Margareta Elg

AstraZeneca R&D, Mölndal, Sweden

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First published: 20 January 2011
Citations: 51
Margareta Blombäck, Bld L2 5th floor, Karolinska University Hospital, 17176 Stockholm, Sweden.
E-mail: [email protected]

Part of the results was presented as a poster at the ISTH congress in Boston July 2009.

Summary

Orally available direct thrombin inhibitors (DTI) and direct activated factor X inhibitors (DFXaI) may replace vitamin K antagonists in patients needing long-term anticoagulant treatment. We investigated the influence on the fibrin network of anticoagulants with different modes of action: AR-H067637 (DTI), the active metabolite of AZD0837, apixaban (DFXaI), fondaparinux (indirect FXaI) and warfarin. Counteraction of the anticoagulant effect by FEIBA® (Factor Eight Inhibitor Bypass Activity) was also investigated. Tissue factor, phospholipids and calcium were used to initiate coagulation in human platelet poor plasma. The permeability constant (Ks), reflecting the amount of buffer passing through the coagulum, was calculated and the fibrin network was visualized by 3D confocal microscopy. Warfarin (International Normalized Ratio 2-3) increased Ks in plasma by 28–50% compared with control. ‘Therapeutic’ plasma concentrations of AR-H067637 (0·3–0·6 μmol/l), apixaban (0·2–0·4 μmol/l) and fondaparinux (0·1–0·3 μmol/l) increased Ks by 72–91%, 58–76% and 36–53% respectively. Addition of FEIBA® totally reversed the warfarin effect but only partially reversed effects of the other anticoagulants at concentrations that increased Ks by 50% or more. Fibrin network observed with 3D confocal microscopy agreed well with the permeability results. In conclusion, all examined anticoagulants rendered the fibrin network more porous. FEIBA® reversed the increased permeability in warfarin plasma but had only partial effects on the other anticoagulants.

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