Antithrombin III patterns in disseminated intravascular coagulation.

Antithrombin III-heparin cofactor has now been recognized as a major inhibitor of thrombin and other serine proteases in the blood coagulation system. Since the reaction between antithrombin III and serine proteases is irreversible, one would expect antithrombin III consumption in the face of pathologic intravascular coagulation and attendant generation of thrombin, IXa, Xa, XIa, XIIa, and plasmin. Using a new assay system for antithrombin III that is unaffected by heparin or fibrino (geno) lytic degradation products, antithrombin III was monitored before and during therapy in 38 patients who had acute or chronic disseminated intravascular coagulation. It was found that early and significant decreases in anththrombin III occur in disseminated intravascular coagulation and thus may serve as a useful diagnostic tool. It was further found that monitoring antithrombin III during therapy reflected a cessation of antithrombin III consumption and, thus, served as an indicator of the efficacy of therapy in stopping the clotting process. Since the assay system is unaffected by fibrino(geno)lytic degradation products and heparin, it proved useful in monitoring the efficacy of heparin therapy for disseminated intravascular coagulation. In addition for this group of patients, it appeared that mini-heparin therapy and large doses of heparin were equally efficacious in correcting other laboratory abnormalities of disseminated intravascular coagulation, and in controlling clinical hemorrhage in disseminated intravascular coagulation.