Modern view on hemostasis system: cell theory

Abstract

For many years, there has been no model capable of explaining the complex processes of interaction between various bloodclotting factors leading to a stop of bleeding. One of the most successful models able to partially reflect the mechanisms of hemostasis for a long time was the cascade theory. The cascade model perfectly explains the processes occurring during coagulation in vitro, but was completely inadequate in attempts to evaluate the processes occurring in vivo. A significant drawback of the cascade model is the impossibility to trace the interaction of cells carrying the tissue factor, platelets and plasma coagulation factors on their surface, since these conditions cannot be imitated. The cell theory, which has replaced the cascade theory, pays attention not only to the interaction of plasma coagulation factors, but also takes into account the role of platelets as important participants of coagulation processes. It is based on a four-stage reaction cascade that includes the following stages: initiation, amplification, propagation, and termination.The cell theory of hemostasis is able to reflect the complex process of interaction of all the links of hemostasis and answer questions related to the problems in patients with disorders of the coagulation system. The cell theory of hemostasis allows to reflect more precisely the processes of hemostasis in vivo and to interpret correctly the results of tests and pathophysiological mechanisms of disorders of the coagulation system. Global tests (thrombin generation assay, thromboelastography, thrombodynamics) used for hemostasis system evaluation are more complimentary with cell theory of hemostasis.