PB1842 ROLE OF THROMBOELASTOGRAPHY IN THE MONITORING OF PROPHYLACTIC TREATMENT IN PATIENTS WITH SEVERE HAEMOPHILIA A

Background: According to many experts, during prophylactic treatment, the activity of factor VIII (FVIII) is not a sufficient predictor of the effectiveness of prevention and does not reflect the level of risk of bleeding. During monitoring of the therapy with activated partial thromboplastin time (APTTT) and FVIII activity, the cause of the discrepancy may be unaccounted content of the tissue factor, the amount and the aggregative function of the thrombocytes, which are also involved in the coagulation process. Therefore, global laboratory methods, in particular thromboelastography (TEG), are used to control therapy Aims: To study the role of TEG in the monitoring the prophylactic treatment of clotting factors concentrates in patients with haemophilia Methods: The study was performed in 9 patients with severe haemophilia A, who received prophylactic treatment by prolonged recombinant FVIII concentrate at a dose of 45 ± 5 IU/ kg two times a week. According to international recommendations all the patients were tested for incremental recovery (IR) of the administered concentrate FVIII in a dose of 60 ± 5 IU/kg during their routine visits. Pre‐ and post‐infusion coagulation tests and TEG (TEG 5000® Haemoscope Corp., Niles IL) were performed Results: Pre‐infusion the indicators of coagulation tests that characterized coagulation hemostasis (APTT‐72,9 sec, FVIII‐1,1%) were prolonged. 30 minutes post‐infusion the abnormal value came to the norm. The prothrombin time (PT), the fibrinogen level and quantity of platelets in the IR test did not differ from the corresponding values of healthy individuals. In TEG, the prolonged reaction time to clot formation R (21,9 sec), the time of maximum amplitude TMA (46,5 sec), the time of initial fibrin formation SP (19,1 min), the reduced rate of initial clot strengthening α‐Angel (33,0°), negative value of coagulation index CI (‐3,0) indicate a violation of the enzymatic phase of blood clotting. Post‐infusion of the calculated dose of the medication, all of the abnormal parameters returned to normal. In IR test, TEG parameters that characterize strength, quality, hemostatic capabilities, lysis of the clot and depend on the level of fibrinogen and platelets do not differ from those of healthy individuals Summary/Conclusion: TEG can be a reliable method for monitoring prophylactic treatment and IR in patients with hemophilia A without inhibitors in combination with coagulation tests (APTT, FVIII activity). The following parameters should be analyzed: the reaction time to clot formation R, the time of maximum amplitude TMA, initial fibrin formation SP, the rate of initial clot strengthening α‐Angel, the total coagulation potential CI