Physiology of hemostasis.

ABSTRACT

The consequences of acute insults to the hemostatic system, whether congenital or acquired, frequently present a considerable challenge in diagnosis and therapy. Logical and effective management depends upon the proper identification of the hemostatic compartments involved; an appreciation for the considerably complex, delicately modulated interplays of various enzyme/inhibitor systems; and knowledge of the mechanism by which a variety of apparently unrelated disease processes precipitate sometimes catastrophic events--thrombosis/embolism/hemorrhage. We have attempted a logical review of basic mechanisms of hemostasis. The text is obligatorily brief, focusing on key elements of the biochemistry and physiology of the vessel wall, the platelet, and pertinent plasma factors. The section on plasma proteins pays particular attention to biocybernetic principles (positive/negative feedback loops) and to the interrelationship of enzyme systems involved in coagulation, fibrinolysis, kinin generation, and complement activation. No attempt was made to be encyclopedic. In the interest of brevity and clarity, the text has been limited to current concepts, with the reference material selected, whenever possible, in the form of review articles, volumes and monographs. We apologize for omissions. It is our belief that a working knowledge of basic mechanisms provides not only advantages in diagnostic/therapeutic management but also serves as a firm foundation for the development of novel diagnostic and therapeutic modalities.