Аspects of the methodology of laboratory studies of hemostasis in pediatric hematology-oncology and general approaches in the pathology of hemostasis in leukemia

Abstract

Children with acute leukemia are faced with high risks of thrombotic and hemorrhagic complications. The pathogenesis of haemostasis disorders in hemoblastoses is complex because, in addition to the disease itself, the aggressiveness of the therapy and the need for numerous invasive manipulations also make a significant contribution. Patients with hemoblastoses are equally susceptible to thrombosis and hemorrhage, which makes it possible to speak of multidirectional shifts in the balance of the hemostatic system in each individual patient. Standard laboratory hemostasis tests (clotting times, marker tests) are designed to assess the concentrations of individual proteins and the functioning of individual components of the hemostasis, and in do not assess the balance between its procoagulant and anticoagulant components. Global hemostatic tests designed to assess the coagulation balance, such as thromboelastography, thrombin generation test, and thrombodynamics, can be the alternative for the standard coagulation assays. The review focuses on the mechanisms of various laboratory hemostasis tests, as well as an assessment of their informative value in frequent complications of the underlying disease (sepsis leading to the development of disseminated intravascular coagulation (DIC) syndrome, thrombocytopenia) and catheterization, which is present in the majority of patients with hemoblastosis. General screening tests of the blood coagulation system have little diagnostic value in the DIC syndrome in patients with acute leukemia, mainly due to their insensitivity to hypercoagulability. Standard markers (for example, D-dimers) are non-specific and only confirm the clinical manifestations of clotting disorder in sepsis and septic shock, but are unable to predict the dynamics of this process at earlier stages of the inflammatory response. In this case, the thrombin generation test and thrombodynamics make it possible to reveal the hypercoagulable phase of the DIC syndrome. Thrombocytopenia accompanies almost all protocols of chemotherapy. In this case, the degree of bleeding does not always depend only on the concentration of platelets, since chemotherapeutic drugs can affect not only the quantity, but also the functional characteristics of platelets, which are not determined by standard examination of patients. The catheterization that accompanies the treatment of hemoblastoses is the leading cause of thrombosis in children with acute leukemia. Thromboembolism of the pulmonary artery due to thrombosis in the central vein system occurs in 8–15 % of patients. The prediction of catheter-associated thromboses using standard laboratory methods for assessing the state of the hemostasis is not possible. Absence of sensitive tests in modern diagnostic schemes leads to the fact that the attending physician is forced to focus exclusively on the clinical picture of thrombosis or bleeding. The development of new functional methods of hemostasis allows one to think that today the existing standard panel of coagulation tests can be expanded and made much more informative in terms of the prediction of thrombohemorrhagic complications in pediatric hematology-oncology.