Importance of measuring plasma thrombin-antithrombin III complex levels when using antithrombin III concentrate...

We investigated changes in the concentrations of thrombin-antithrombin III complex (TAT) and plasmin-alpha 2 plasmin inhibitor complex (PIC) after the intravenous administration of 4000 units of antithrombin III (AT III) concentrate to patients with fulminant hepatic failure (FHF), subacute hepatitis (SH), or liver cirrhosis (LC). FHF patients showed shortening of the initial half-life of exogenous AT III. In addition, a marked rise in plasma TAT was noted 3 to 6 h after the intravenous administration of AT III, even in patients who had a normal plasma TAT level before AT III therapy. In contrast, SH and LC patients showed no marked changes of plasma TAT levels after AT III administration. No marked changes were observed in the PIC concentration in any of the patients. These findings suggest that thrombin formation is increased in FHF and that simple measurement of the plasma TAT concentration is not an adequate method for assessing thrombin formation in FHF patients who have suspected disseminated intravascular coagulation associated with an apparent decrease in AT III synthesis. Instead, it seems necessary to measure the plasma TAT concentration in FHF patients after replacement therapy with AT III concentrate has been performed, to evaluate their hypercoagulability more accurately.