Human plasma extrinsic pathway inhibitor activity: II. Plasma levels in disseminated intravascular coagulation and hepatocellular disease

Plasma or serum extrinsic pathway inhibitor (EPI) activity was measured in 24 patients with disseminated intravascular coagulation (DIC) and in 23 patients with severe hepatocellular disease. EPI was measured as activity in a test sample that inhibited factor VIIa/tissue factor (TF)- catalyzed activation of 3H-factor IX (activation peptide release) in the presence of factor X. Of the 24 patients with DIC, 13 had sepsis and five had metastatic carcinoma, disorders in which tissue factor is believed to initiate DIC. EPI activity ranged from 68% to 300% (mean 134% +/- 50%). Serial measurements in nine patients failed to show depletion of EPI activity coincident with worsening DIC. DIC induced by tissue factor or other activating materials may progress despite normal EPI levels. In the patients with liver disease, of whom 15 had decompensated chronic hepatocellular disease (two fatal cases) and eight had acute fulminant liver failure (seven fatal cases), plasma or serum EPI activity varied from less than 20% to 194%. Values were distributed in a bimodal fashion. EPI activity could not be correlated with either the etiology of the liver disease or the degree of prolongation of the prothrombin time. Patients with chronic hepatocellular disease who survived had normal or elevated EPI activity. Patients with fatal hepatic dysfunction had low, normal, or high values for EPI activity. This must mean that secretion of EPI from cells other than hepatocytes can maintain normal plasma EPI levels.