Heparin Ablates Force Development during Platelet Mediated Clot Retraction

Summary

Although snake venom enzymes such as reptilase do not cause viscous metamorphosis, platelet secretion or clot retraction; when batroxobin and calcium are added to citrated blood significant platelet force development occurs. When this batroxobin-calcium system was applied to the study of platelet function during cardiopulmonary bypass (CPB), force development was found to be completely inhibited. After heparin reversal by protamine sulfate, significant recovery of force occurred. The present investigation was performed to evaluate the role of heparin in reducing force development during CPB. At concentrations above 0.10 U/ml, heparin totally suppressed force development in normal plasma. Addition of protamine sulfate to heparinized plasma caused complete recovery of force development. These concentrations of heparin had little effect on platelet aggregation by ADP or collagen. Possible direct effects of heparin on fibrin assembly and structure were studied by adding varying amounts of heparin to plasma and then inducing clot formation with batroxobin. At 1 U/ml, heparin reduced the size of fibrin fibers by 33%. Higher heparin concentrations had no additional effect. These results indicate that heparin may be responsible for a significant component of the decreased platelet force noted during cardiopulmonary bypass. To test whether heparin’s effect could be due to suppression of thrombin activity, the effects of the antithrombin hirudin on force development were measured. Hirudin also inhibited force development in a concentration dependent manner. Thus, heparin’s reduction of platelet force development may be due, at least in part, to suppression of thrombin activity.

• References

• 1 Salzman EW, Deykin D, Shapiro RM, Rosenberg RD. Management of heparin therapy. Controlled prospective trial. N Engl J Med 1975; 292: 1046-1050
• 2 Buchanan MR, Nguyen P, Van Ryn J, Ofosu FA, Hirsh J. DDAVP reduces the platelet defect associated with heparin. Circulation 1986; 74 (Suppl. 02) 11-95
• 3 Heiden D, Mielke Jr CH, Rodvien R. Impairment by heparin of primary haemostasis and platelet [14C]5-hydroxtryptamine release. Br J Haematol 1977; 36: 427-436
• 4 Suzuki K, Nishioka J, Hashimoto S. Inhibition of factor VUI-associated platelet aggregation by heparin and dextran sulfate, and its mechanism. Bio-chim Biophys Acta 1979; 585: 416-426
• 5 Sobel M, McNeill PM, Carlson PL, Kermode JC, Adelman B, Conroy R, Marques D. Heparin inhibition of von Willebrand Factor-dependent Platelet function in vitro and in vivo. J Clin Invest 1991; 87: 1787-1793
• 6 Carr ME, Zekert SL. Force monitoring of clot retraction during DDAVP therapy for the qualitative platelet disorder of uraemia: Report of a case. Blood Coagul Fibrinolysis 1991; 2: 303-308
• 7 Carr ME, Zekert SL. Measurement of platelet mediated force development during plasma clot formation. Am J Med Sci 1991; 302: 13-18
• 8 Greilich PE, Carr ME, Carr SL, Chang AS. Reductions in platelet force development by cardiopulmonary bypass are associated with hemorrhage. Anesth Analg 1995; 80: 459-465
• 9 Niewiarowski S, Regoeczi E, Stewart GJ, Senyi AF, Mustard JF. Platelet interaction with polymerizing fibrin. J Clin Invest 1972; 51: 685-700
• 10 Niewiarowski S, Regoeczi E, Mustard JF. In New York Academy of Sciency: Conference on platelets and their role in hemostasis. Abstract 6 1971
• 11 de Gaetano G, Bottecchia D, Vermylen J. Retraction of reptilase-clots in the presence of agents inducing or inhibiting the platelet adhesion-aggregation reaction. Thromb Res 1973; 2: 71-84
• 12 de Gaetano G, Franco R, Donati MB, Bonaccorsi A, Garattini S. Mechanical recording of reptilase-clot retraction: Effect of adenosine-5′-diphos-phate and prostaglandin E1. Thrombin Res 1974; 4: 189-192
• 13 de Gaetano G, Bottecchia D, Vermylen J. Effect of platelets on clot structuration. A thromboelastographic study. Thromb Res 1973; 3: 425-435
• 14 Carr ME, Powers PL. Effect of glycosaminoglycans on thrombin- and atroxin-induced fibrin assembly and structure. Thromb Haemost 1989; 62: 1057-1061
• 15 Carr ME, Carr SL. Abnormal clot retraction, altered fibrin structure and normal platelet function in multiple myeloma. Am J Physiol 1994; 266: H1195-H1201
• 16 Clauss A. A rapid physiological coagulation method for determination of fibrinogen. Acta Haematol 1957; 17: 237-246
• 17 Carr ME, Gabriel DA. The effect of dextran 70 on the structure of plasma-derived fibrin gels. J Lab Clin med 1980; 96: 985-993
• 18 Carr ME, Gabriel DA. Dextran-induced changes in fibrin fiber size and density based on wavelength dependence of gel turbidity. Macromolecules 1980; 13: 1473-1477
• 19 Carr ME, Hermans J. Size and density of fibrin fibers from turbidity. Macromolecules 1978; 11: 46-50
• 20 Carr ME, Gabriel DA, McDonagh J. Influence of Calcium on the Structure of Reptilase and Thrombin Derived Fibrin Gels. Biochem J 1986; 239: 513-516
• 21 Carr ME. Fluid Phase Coagulation Events Have Minimal Impact on Plasma Fibrin Structure. Am J Med Sci 1988; 295: 433-437
• 22 Carr ME. Fibrin Formed in Plasma Is Composed of Fibers More Massive Than Those Formed From Purified Fibrinogen. Thromb Haemost 1988; 59: 535-539
• 23 Harker L, Malpass TW, Branson HE, Hessel II EA, Slichter SJ. Mechanism of abnormal bleeding in patients undergoing cardiopulmonary bypass: Acquired transient platelet dysfunction associated with selective alpha-granule release. Blood 1980; 56: 824-834
• 24 John LC, Rees GM, Kovacs IB. Effect of heparin on in vitro platelet reactivity in cardiac surgical patients - a comparative assessment by whole blood platelet aggregometry and haemostatometry. Thromb Res 1992; 66: 649-656
• 25 John LC, Rees GM, Kovacs IB. Inhibition of platelet function by heparin. An etiologic factor in postbypass hemorrhage. J Thorac Cardiovasc Surg 1993; 105: 816-822
• 26 John LC, Rees GM, Kovacs IB. Different anticoagulants and platelet reactivity in cardiac surgical patients. Ann Thorac Surg 1993; 56: 899-902
• 27 Shainoff JR, Estafanous G, Yared JP, DiBello PM, Kottke-Marchant K, Loop FD. Low factor XHIa levels are associated with increased blood loss after coronary artery bypass grafting. J Thorac Cardiovasc Surg 1994; 108: 437-445
• 28 Carr ME, Carr SL. At high heparin concentrations, protamine concentrations which reverse anticoagulant effects are insufficient to reverse heparin antiplatelet effects. Thromb Res 1994; 75: 617-630
• 29 Brister SJ, Ofosu FA, Heigenhauser GJF, Gianese F, Buchanan MR. Is heparin the ideal anticoagulant for cardiopulmonary bypass? Dermatan sulphate may be an alternate choice. Thromb Haemost 1994; 71: 468-473