Systemic fibrinolytic activity and inhibitor levels during treatment of deep vein thrombosis with urokinase and streptokinase.

In a prospective, randomized trial 33 patients with deep vein thrombosis were treated either with 2,200 or 1,100 IU/kg/h urokinase or with 100,000 IU/h streptokinase for at least 6 days. While streptokinase was given continuously, urokinase was administered intermittently (12 hr urokinase alternating with 12 hr heparin). Urokinase treatment resulted in a dose-dependent fibrinolytic state with shortening of the euglobulin clot lysis time, easily demonstrable amidolytic activity and moderate decrease of plasminogen. At the end of each urokinase-free interval the fibrinolytic activity had mostly faded, but was reproducibly elicited again by each new urokinase administration. Streptokinase immediately evoked the customary, intense fibrinolytic state, which progressively tapered off as plasminogen fell to 1% of its pretreatment concentration. In all treatment groups alpha-2-antiplasmin dropped to approximately 40% of its initial value during the first 12 hr with a further decrease to about 20% after 6 days. alpha-2-macroglobulin fell only moderately with either urokinase regimen, whereas it decreased progressively to 45% under streptokinase. While the fibrinolytic activity decreased under streptokinase over the 6-day infusion period, it appeared to increase with each successive urokinase infusion particularly with 1100 IU/kg/h. Thus the final euglobulin clot lysis times and the final fibrinogen concentrations were similar in all three treatment groups on the sixth day.