The direct thrombin inhibitors (argatroban, bivalirudin and lepirudin) and the indirect Xa-inhibitor (danaparoid) increase fibrin network porosity and thus facilitate fibrinolysis

Summary

The present study aimed to assess whether the fibrin network structure is modified by the direct thrombin-inhibitors lepirudin, argatroban or bivalirudin and by the indirect Xa-inhibitor danaparoid. Using an in vitro assay that imitates the physiological process of coagulation from thrombin generation to fibrin formation, we examined a normal plasma pool spiked with one of the inhibitors. At concentrations considered to be the plasma levels observed during therapy, almost no influence was detected for lepirudin despite clear-cut effects on “clotting time”. However, argatroban, bivalirudin and danaparoid increased the fibrin gel permeability (Ks) to a similar extent. At concentrations higher than the “therapeutic” levels, the dose-response curve in the Ks assay became very steep for lepirudin while those were shallow for the others. In parallel with the drug-induced increases of Ks, larger network pores in 3D-microscopic images and significant shortenings in “clot lysis time” induced by addition of rtPA were observed. Recombinant factor VIII (rFVIII) added to danaparoid-treated samples profoundly counteracted the increase of Ks but had only a slight or no effect on the other drugs. Thus, in vitro, argatroban, bivalirudin and danaparoid have comparable anticoagulating effects, rendering the fibrin network more permeable and less resistant to fibrinolysis. For lepirudin, the steep dose-response curve supports previous clinical findings, i.e. this thrombin inhibitor has a narrow therapeutic window. Furthermore, our data suggest that the haemostatic agent, rFVIII, might be effective in treatment of bleeding complications induced by danaparoid.

Keywords

Thrombin inhibitor - factor-Xa inhibitor - fibrin network porosity - fibrinolysis - recombinant FVIII

• References

• 1 Gustafsson D, Bylund R, Antonsson T. et al. A new oral anticoagulant: the 50-year challenge. Nat Rev Drug Discov 2004; 03: 649-659.
• 2 De Caterina R, Husted S, Wallentin L. et al. Anticoagulants in heart disease: current status and perspectives. Eur Heart J 2007; 28: 880-913.
• 3 Bauer KA. New anticoagulants. Curr Opin Hematol 2008; 15: 509-515.
• 4 Nair CH, Azhar A, Wilson JD. et al. Studies on fibrin network in human plasma. Part II-Clinical application:diabetes and antidiabetic drugs. Thromb Res 1991; 64: 477-485.
• 5 Fatah K, Hamsten A, Blombäck B. et al. Fibrin gel network characteristics and coronary heart disease: relations to plasma fibrinogen concentration, acute phase protein, serum lipoproteins and coronary atherosclerosis. Thromb Haemost 1992; 68: 130-135.
• 6 Collet JP, Mishal Z, Lesty C. et al. Abnormal fibrin clot architecture in nephrotic patients is related to hypofibrinolysis: influence of plasma biochemical modifications: a possible mechanism for the high thrombotic tendency?. Thromb Haemost 1999; 82: 1482-1489.
• 7 Blombäck B. Fibrinogen and fibrin – proteins with complex roles in hemostasis and thrombosis. Thromb Res 1996; 83: 1-75.
• 8 Collet JP, Park D, Lesty C. et al. Influence of fibrin network conformation and fibrin fiber diameter on fibrinolysis speed: dynamic and structural approaches by confocal microscopy. Arterioscler Thromb Vasc Biol 2000; 20: 1354-1361.
• 9 Wolberg AS, Allen GA, Monroe DM. et al. High dose factor VIIa improves clot structure and stability in a model of haemophilia B. Br J Haematol 2005; 131: 645-655.
• 10 Varin R, Mirshahi S, Mirshahi P. et al. Clot structure modification by fondaparinux and consequence on fibrinolysis: a new mechanism of antithrombotic activity. Thromb Haemost 2007; 97: 27-31.
• 11 He S, Blombäck M, Jacobsson Ekman G. et al. The role of recombinant factor VIIa (FVIIa) in fibrin structure in the absence of FVIII/FIX. J Thromb Haemost 2003; 01: 1215-1219.
• 12 Blombäck B, Carlsson K, Fatah K. et al. Fibrin in human plasma: gel architectures governed by rate and nature of fibrinogen activation. Thromb Res 1994; 75: 521-538.
• 13 Blombäck B, Carlsson K, Hessel B. et al. Native fibrin gel networks observed by 3D microscopy, permeation and turbidity. Biochim Biophys Acta 1989; 997: 96-110.
• 14 He S, Wallen H, Johnsson H. et al. In vitro effects of argatroban, lepirudin, bivalirudin and danaparoid on fibrin gel permeability. Semin Thromb Hemost 2008; 34 (Suppl. 01) 91-96.
• 15 He S, Zhu K, Skeppholm M, Vedin J. et al. A global assay of haemostasis which uses recombinant tissue factor and tissue-type plasminogen activator to measure the rate of fibrin formation and fibrin degradation in plasma. Thromb Haemost 2007; 98: 871-882.
• 16 He S, Cao H, Antovic A. et al. Modifications of flow measurement to determine fibrin gel permeability and the preliminary use in research and clinical materials. Blood Coagul Fibrinolysis 2005; 16: 61-67.
• 17 von dem Borne PA, Meijers JC, Bouma BN. Feedback activation of factor XI by thrombin in plasma results in additional formation of thrombin that protects fibrin clots from fibrinolysis. Blood 1995; 86: 3035-3042.
• 18 Harenberg J, Jörg I, Fenyvesi T. et al. Treatment of patients with a history of heparin-induced thrombocytopenia and anti-lepirudin antibodies with argatroban. J Thromb Thrombolysis 2005; 19: 65-69.
• 19 Shah AC, Genoni M, Niederhäuser U. et al. R-hirudin (lepirudin, refludan) as an alternative anticoagulant in heparin-induced thrombocytopenia during cardio-pulmonary bypass connection. Schweiz Med Wochenschr 2000; 23: 896-899.
• 20 Cardot JM, Lefèvre GY, Godbillon JA. Pharmacokinetics of rec-hirudin in healthy volunteers after intravenous administration. J Pharmacokinet Biopharm 1994; 22: 147-156.
• 21 Cox DS, Kleiman NS, Boyle DA. et al. Pharmacokinetics and pharmacodynamics of argatroban in combination with a platelet glycoprotein IIB/IIIA receptor antagonist in patients undergoing percutaneous coronary intervention. J Clin Pharmacol 2004; 44: 981-990.
• 22 Ahmad S, Iqbal O, Ahsan A. et al. Clinical laboratory monitoring of a synthetic antithrombin agent, argatroban, using high performance liquid chromatography and functional methods. Int Angiol 1999; 18: 198-205.
• 23 Boggio LN, Oza VM. Argatroban use in heparin-induced thrombocytopenia. Expert Opin Pharmacother 2008; 09: 1963-1967.
• 24 Carroll RC, Chavez JJ, Simmons JW. et al. Measurement of patients’ bivalirudin plasma levels by a thrombelastograph ecarin clotting time assay: a comparison to a standard activated clotting time. Anesth Analg 2006; 102: 1316-1319.
• 25 Cho L, Kottke-Marchant K, Lincoff AM. et al. Correlation of point-of-care ecarin clotting time versus activated clotting time with bivalirudin concentrations. Am J Cardiol 2003; 09: 1110-1113.
• 26 Casserly IP, Kereiakes DJ, Gray WA. et al. Point-of-care ecarin clotting time versus activated clotting time in correlation with bivalirudin concentration. Thromb Res 2004; 113: 115-121.
• 27 Warkentin TE, Greinacher A, Koster A. Bivalirudin. Thromb Haemost 2008; 99: 830-839.
• 28 Krauel K, Fürll B, Warkentin TE. et al. Heparin-induced thrombocytopenia--therapeutic concentrations of danaparoid, unlike fondaparinux and direct thrombin inhibitors, inhibit formation of platelet factor 4-heparin complexes. J Thromb Haemost 2008; 06: 2160-2167.
• 29 Carrier M, Robitaille D, Perrault LP. et al. Heparin versus danaparoid in off-pump coronary bypass grafting: results of a prospective randomized clinical trial. J Thorac Cardiovasc Surg 2003; 125: 325-329.
• 30 Westphal K, Martens S, Strouhal U. et al. Heparin-induced thrombocytopenia type II: perioperative management using danaparoid in a coronary artery bypass patient with renal failure. Thorac Cardiovasc Surg 1997; 45: 318-320.
• 31 Hemker HC, Giesen P, AlDieri R. et al. The calibrated automated thrombogram (CAT): a universal routine test for hyper- and hypocoagulability. Pathophysiol Haemost Thromb 2002; 32: 249-253.
• 32 Samama MM, Le Flem L, Guinet C. et al. Three different patterns of calibrated automated thrombogram obtained with six different anticoagulants. J Thromb Haemost 2007; 05: 2554-2556.
• 33 Robert S, Ghiotto J, Pirotte B. et al. Is thrombin generation the new rapid, reliable and relevant pharmacological tool for the development of anticoagulant drugs?. Pharmacol Res 2009; 59: 160-166.
• 34 Elg M, Carlsson S, Gustafsson D. Effect of activated prothrombin complex concentrate or recombinant factor VIIa on the bleeding time and thrombus formation during anticoagulation with a direct thrombin inhibitor. Thromb Res 2001; 10: 145-157.
• 35 Greinacher A, Warkentin TE. The direct thrombin inhibitor hirudin. Thromb Haemost 2008; 99: 819-829.
• 36 Dang CH, Durkalski VL, Nappi JM. Evaluation of treatment with direct thrombin inhibitors in patients with heparin-induced thrombocytopenia. Pharmacotherapy 2006; 26: 461-468.
• 37 Tardy B, Lecompte T, Boelhen F. et al. GEHT-HIT Study Group. Predictive factors for thrombosis and major bleeding in an observational study in 181 patients with heparin-induced thrombocytopenia treated with lepirudin. Blood 2006; 108: 1492-1496.
• 38 Adkins JC, Wilde MI. Lepirudin: a review of its potential place in the management of thrombotic disorders. BioDrugs 1998; 10: 227-255.