Laboratory rationale for dose reduction anticoagulant for thrombosis complicing treatment patients with hemoblastosis on the background of chemioinduced thrombocytopenia

Purpose of the study: To substantiate the minimum hemostatic threshold for platelet count, which regulates the anticoagulant therapy of thrombosis against the background of induced thrombocytopenia in children with malignant neoplasms. Material and research methods: 23 patients (group 1) with hemorrhagic syndrome caused by thrombocytopenia (less than 50∙109/l) were examined. The control group consisted of 21 patients (group 2) with a similar diagnosis, platelet count less than 150∙109/l, who did not have bleeding. All examined patients with hemoblastoses had signs of febrile neutropenia. Additionally, under the conditions of a bench experiment, dilutions of platelet donor plasma were prepared with a platelet content of 5.0×109/l, 10.0×109/l, 20.0×109/l, 30.0×109/l, 40.0×109/L, 50.0×109/L, 60.0×109/L, 70.0×109/L, 80.0×109/L, 90.0×109/L, 100.0×109 /l, 200.0×109/l. Platelets were counted in peripheral blood for each sample using an XN-3000 hematology analyzer (manufactured by Sysmex GmbH, Japan) by the impedance method using original reagents (SysmexGmbH). The endogenous thrombin potential (ETP) in patients' platelet plasma was determined by the Hemker method on a Fluoroskanascent fluoroscan manufactured by Thermo Electron Corporation (Maastricht, Netherlands) using reagent kits from Thrombinoscop eBV. Research results: Between the content of platelets in whole blood and EPT of platelet plasma of patients with hemoblastoses, a relationship was revealed, which is reflected by the regression equation: y = 15.1356 + (0.0745∙ x), where y is the content of platelets in the blood (109/l), and x - EPT nM/l∙min in venous blood plasma. The minimum threshold value of EPT of platelet plasma, which provides hemostasis, 250 nM/l∙min, corresponded to the minimum platelet content of 30.0∙109/l in the blood of FN patients. Decrease in the content of platelets in donor plasma less than 20×109/l led to a decrease in EPT less than 250 nM/l•min. Between the EPT generated in the platelet donor plasma and the content of platelets in the donor plasma in the range (100.0 -20.0) ×109/l, a linear relationship was revealed. When the content of platelets was more than 100.0×109/l, generated by platelet plasma, EPT increased, regardless of the increase in the content of platelets in the plasma under study. Conclusion: in case of thrombosis against the background of chemo-induced thrombocytopenia in the range (100.0 -20.0)×109/l, the patient should receive LMWH at a dose reduced in proportion to the content of platelets in the blood.