الفهرس 
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Abstract
The liver plays a central role in the hemostatic system as it synthesizes the majority of coagulation factors and proteins involved in fibrinolysis. Furthermore, the liver produces thrombopoeitin, which is responsible for platelet production from megakaryocytes. Consequently, chronic or acute liver diseases frequently have a profound impact on the hemostatic system. An important contributor to the coagulation disturbances in liver disease is decreased plasma levels of hemostatic proteins synthesized by the liver. Additionally, thrombocytopenia as a result of decreased platelet production or increased platelet turnover and intravascular activation of hemostasis resulting in consumption of hemostatic factors contribute to alterations in the hemostatic system. Furthermore, continuous low-grade activation of endothelial cells results in continuous release of a number of hemostatic proteins whose levels are therefore frequently elevated in patients with liver disease (e.g. von Willebrand factor). Finally, portal hypertension, which is a common complication of chronic liver failure results in hemodynamic changes that may impact endothelial function and splenomegaly, which results in increased platelet sequestration in the spleen.
Routine laboratory tests of hemostasis such as the platelet count, the prothrombin time (PT) and the activated partial thromboplastin time (APTT) are frequently abnormal in patients with liver disease. The combination of thrombocytopenia with a prolonged PT and APTT is suggestive of a bleeding diathesis, and it is traditionally assumed that patients with liver failure are at risk for bleeding as a result of these hemostatic changes.
Consequently, it is common practice to prophylactically correct a prolonged PT and APTT prior to invasive procedures by administration of fresh-frozen plasma. Blood product use in patients with liver disease is substantial, and a significant proportion is used prophylactically (and not in actively bleeding patients), although exact figures have not been reported. However, a recent survey on the use of blood products indicated that hepatobiliary indications were the one of the primary indications for fresh frozen plasma (FFP) and platelet concentrate transfusion, and also a frequent indication in recipients of packed red cells.