Hemostaseology
The Hemostasis is the study of blood clotting (from Greek. Αἷμα haima "blood" and στάσις stasis "standstill") and its disorders. The term hemostaseology was introduced in 1953 by the Munich hematologist Rudolf Marx (1912–1990). He understood it to be "the doctrine of the blood stopping and getting stuck". According to today's understanding, hemostaseology also includes the teaching of disorders or imbalances in hemostasis and the diseases resulting from them.
It is the specialty of medicine that deals with hemostasis and thus all those factors that are essential to stop bleeding or lead to a disruption of it. In line with the importance of this specialty, most medical universities have institutes for hemostaseology and transfusion medicine alongside non-university institutes
Essential aspects of hemostaseology are:
- intact blood clotting itself (including the interaction of all coagulation factors )
- the undisturbed function of the endothelium as the inner lining of the vascular wall and the thrombocytes (blood platelets)
- the factors that counteract blood clotting such as antithrombins and fibrinolysis through the action of plasmin
The main task of the hemostasis system is to enable successful wound healing . A typical clinical correlate of disorders of hemostasis is therefore represented by disorders of wound healing. A first step on the way to wound healing is hemostasis, which is nevertheless more obvious than wound healing and is therefore often seen as the main goal of hemostasis. The term hemostasis is understood here to mean the complex interplay of processes, tissues, cells and soluble substances, through which, on the one hand, the ability of the blood to flow at any place and at any time and, on the other hand, at the same time its coagulability after injury - again in every place and at every time - is guaranteed. Ultimately, this enables the vascular and tissue structures to be restored through repair processes. This already shows that hemostasis cannot occur solely as a cascade system, but rather represents a complex network that enables the functionality and interaction of blood vessels, blood flow, platelets and other blood cells as well as soluble coagulation proteins, the coagulation system in the narrower sense. The regulation of these interactive systems therefore takes place on different levels: through cell surfaces, cell receptors and products, as well as through activators and inhibitors.
The common subdivisions of hemostasis such as the plasmatic coagulation system into an exogenous or extrinsic system on the one hand and an endogenous or intrinsic system on the other hand are therefore mostly didactically motivated. What is shown separately in the diagrams is much more closely interlinked in vivo and in terms of time until it cannot be separated, an aspect that must always be taken into account, especially with regard to therapeutic approaches. The immediate sealing of a vessel after injury is achieved through a fast-acting mechanism called primary hemostasis. It is essential for the interaction of vasoconstriction, Endothelreaktion and platelet adhesion and aggregation . At the same time, the plasmatic coagulation is activated as a secondary hemostasis, which decisively determines the solidification of a thrombus by fibrin . In terms of the principles of closely interlinked systems formulated above, however, this classification must not be strictly applied: rather, their interaction is influenced by numerous other factors such as the diversity of different vascular sections and the blood flow.
Most of the plasmatic components of the hemostasis system exist as zymogens (inactive precursors) which, when activated by limited proteolysis, turn into serine proteases (the active proteolytic region lies within a serine-centered peptide). The interactive reactions that take place during coagulation activation lead to an amplification process in which micromolar amounts of the initial reaction partners ultimately lead to the conversion of large amounts of fibrinogen to fibrin.
Both the coagulation system and the fibrinolysis system must be able to be modulated by activators and inhibitors so that a balance is guaranteed and neither bleeding nor unphysiological vascular occlusion (thrombus) can occur. An over shooting and thrombus is ensured by setting activated coagulation factors by the inhibitors is substantially represented by antithrombin , protein C and protein S . Fibrin that has already been formed can be dissolved via proteolytic degradation by the fibrinolysis system, which in turn can be regulated by fibrinolysis inhibitors. In this way, the fibrinolysis system, as an antagonist of the coagulation system, prevents thrombosis of the vascular system. Inhibitors of the fibrinolysis system are in particular the plasmin inhibitor and the fibrinolysis inhibitor TAFI which can be activated by thrombin.
Professional societies
- Society for Thrombosis and Haemostasis Research (GTH): The GTH is the scientific specialist society for haemostaseology in Germany, Austria and Switzerland ( [1] ). Within the GTH there is, among other things, a Standing Commission on Pediatrics and a Standing Commission on Hemophilia. There are also numerous working groups (e.g. "Perioperative Hemostasis", "Thromboses", " Acquired Hemophilia " and others). The conferences take place annually.
- International Society of Thrombosis and Hemostasis (ISTH): ISTH is the international specialist society. [2]
- Haemostaseology within the German Society for Hematology and Medical Oncology (DGHO) : The establishment of the " Haemostaseology Working Group " was decided by the DGHO in October 2002 in order to incorporate the latest scientific haemostaseological findings more quickly into the treatment of patients with haemophilia (increased bleeding tendency) and thrombophilia (increased tendency to clot) to flow in
- German Society for Transfusion Medicine and Immunohematology (DGTI eV), Section "Haemostaseology": The transfusion of blood derivatives plays a central role in the prophylaxis and therapy of haemostasis disorders. Nevertheless, generally recognized diagnostic and therapeutic standards exist for only a few clinical situations. In the Hemostaseology Section, recommendations for diagnostic and therapeutic procedures should be developed based on the clinical question. This also includes the initiation of diagnostic and therapeutic clinical studies for the validation of hemostaseological test procedures and therapeutic approaches.
Remarks
- ^ C. Müller-Berghaus: The concept of "haemostaseology" - history and development , In: Haemostaseology , 2nd edition, Springer Verlag, Heidelberg 2010, p. 2 ( reference ).
- ^ Werlhof Institute
- ↑ DGHO