Tissue plasminogen activator antigen and activity in disseminated intravascular coagulation: clinicopathologic correlations.

The fibrinolytic response to disseminated intravascular coagulation (DIC) has been considered important both in preventing thrombosis and in contributing to hemorrhage. Detailed studies of fibrinolysis in DIC are lacking, however. We measured tissue plasminogen activator (t-PA) antigen and activity levels in 74 patients with DIC, 53 hospitalized patients with similar illnesses without DIC, and 36 healthy normal subjects, using sensitive, specific assays. Mean t-PA antigen levels were significantly higher in patients with DIC than in either hospitalized control subjects or normal individuals in most disease categories studied. Highest t-PA antigen levels were seen in patients with liver disease, but patients with DIC without liver disease also had significantly elevated t-PA antigen. Detectable free t-PA activity was infrequently seen in patients with DIC, however. No correlation was found with either thrombotic or hemorrhagic complications and levels of t-PA antigen or activity in DIC, with the possible exception of increased t-PA activity in two patients with intracranial hemorrhage. Bleeding complications were seen almost exclusively in patients with underlying anatomic lesions, and thrombotic complications were usually associated with other known predisposing factors. We conclude that t-PA antigen is usually elevated in DIC, but free t-PA activity is infrequently seen, most likely because of increased levels of t-PA inhibitor. The presence or absence of free t-PA activity does not appear to predict which patients with DIC will develop hemorrhage or thrombosis.