Behaviour of protein C inhibitor in intravascular coagulation and liver disease.

We measured levels of protein C inhibitor in patients with disseminated intravascular coagulation (DIC) and liver disease using a functional assay. Levels in 24 normal subjects averaged 93% of the amount in normal pooled plasma, giving a normal range of 65 to 121%. Levels were below normal in 8 of 17 patients with DIC, in 4 of 19 patients with liver cirrhosis, and in 3 patients with acute hepatic necrosis. Levels were normal or elevated in 9 of 10 patients with cirrhosis and accelerated fibrinolysis, and in 6 patients receiving warfarin. We conclude that protein C inhibitor may be involved in regulation of protein C activity during pathologic activation of the hemostatic system (DIC). Decreased protein C inhibitor does not appear to contribute to the pathogenesis of accelerated fibrinolysis in liver disease. The liver may be the site of synthesis of protein C inhibitor.