Impairment of hemostasis in the urinary tract: the role of urokinase.

Abstract

Abstract Urokinase, an activator of the plasminogen-plasmin system, is normally present in urine, and confers upon it the ability to lyse fibrin clots. Though the source of urokinase is still an unsettled question, it has been suggested that urokinase may play a role in maintaining the patency of the urinary tract by lysing fibrinous deposits. Since such an action might also serve to impair hemostasis in the urinary tract, an investigation was undertaken of the effect of inhibiting urinary urokinase activity on the duration and extent of the bleeding observed following prostatectomy. Such a study was made possible by the availability of e-aminocaproic acid, a potent inhibitor of urokinase activity, which, when administered intravenously in appropriate dosage, was promptly excreted into the urine in concentrations sufficient to inhibit urokinase activity. It was found that, in association with the inhibition of urokinase activity by this acid, there was a significant (fourfold) reduction in blood loss in e-aminocaproic acid treated patients as compared to the reduction obtained with control subjects. Levels of this acid in the urine were measured, and the excretion rates and relationship between its concentration and urokinase inhibition are discussed. The experimental results provide evidence to support the concept that urokinase can impair hemostasis in the urinary tract and that its inhibition may be attended with improved hemostasis.