THROMBOELASTOGRAPHY SIGNIFICANCE IN THE MONITORING OF PROPHYLACTIC TREATMENT IN PATIENTS WITH SEVERE HAEMOPHILIA A WITHOUT INHIBITORS

Prophylactic treatment of patients with hemophilia A and B is conducted to prevent spontaneous bleeding and the development of hemophilic arthropathy. The high cost of concentrate coagulation factors requires their optimized and rational use. The study of pharmaco- kinetics (incremental recovery-IR) is the basis for choos- ing the dose of the concentrate, the frequency of admin- istration and the control of the development of inhibitors. In addition, global laboratory methods, in particular thromboelastography (TEG), are used to control therapy. During monitoring of the prophylaxis with activated par- tial thromboplastin time (APTT) 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 coag- ulation process. Therefore, the study of TEG informativi- ty for the assessment of hemostatic effects and the control of treatment with concentrates of factors in hemophilia patients is a relevant problem. Aim. To study TEG and traditional hemostasis tests to improve laboratory monitoring of concentrate agents' prophylactic treatment for patients with hemophil- ia A. Materials and methods. The study was per- formed in nine patients with severe hemophilia A, who received prophylactic treatment by prolonged recombi- nant FVIII concentrate at a dose of 45 ± 5 IU/ kg two times a week. According to international recommenda- tions, 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® Haemo- scope Corp., Niles IL) were performed. Results. Pre-infusion the indicators of coagula- tion 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 parame- ters that characterize strength, quality, hemostatic capabil- ities, and lysis of the clot and depend on the level of fi- brinogen and platelets do not differ from those of healthy individuals. Conclusion. TEG can be a reliable method for monitoring prophylactic treatment and IR in patients with hemophilia A. The following parameters that depend on the level of procoagulants should be analyzed: the reac- tion time to clot formation R, the time of maximum am- plitude TMA, initial fibrin formation SP, the rate of initial clot strengthening α-Angel, the total coagulation potential CI. TEG parameters that characterize strength, quality, hemostatic capabilities, and lysis of the clot and depend on the level of fibrinogen and platelets are not informative for monitoring prophylactic treatment and IR in patients with hemophilia. Monitoring of prophylaxis and devel- opment of inhibitors by IR in patients with hemophilia can be done using TEG in combination with coagulation tests (APTT, ІAPTT, FVIII activity, FVIII: Ag).