Antithrombin III metabolism in patients with liver disease.

Liver diseases are associated with complex haemostasis defects, in which platelets, coagulation, and fibrinolysis may all be affected. The low plasma concentrations of clotting factors often found can be the result of many changes such as impaired synthesis, increased catabolism due to intravascular coagulation, or alternate distribution. In this study, we investigated the metabolism of purified human antithrombin III(AT III) labelled with 125I in 25 patients with histologically established liver disease and in nine control subjects. The results showed that, in general, low plasma concentrations of AT III in liver cirrhosis are not due to consumption in the central compartment but rather to altered transcapillary flux ratio. Such altered transcapillary flux ratios may already exist even with normal plasma AT III concentrations. Altered ratios are not only found for coagulation proteins but also for albumin and thus may be a general phenomenon of liver disease. In micronodular cirrhosis the alpha phase, the transcapillary efflux (k1, 2) and influx (k2, 1) were significantly increased compared with the normal subjects.