SummaryForty-one patients with phlebographically proven DVT of the popliteal, femoral or iliac veins were treated with different regimens of urokinase (UK) given by continuous intravenous infusion. The four groups were comparable with respect to localization, extension and estimated age of the thrombi. Another phlebographic picture was taken within 48 hr after the end of UK infusion. Substantial lysis had occurred in 2 of 10 patients treated with 1500 U/kg/h for 2 days, in 4 of 11 treated with 2500/U/kg/h for 3 days, in 2 of 10 treated with 2500 U/kg/h for 7 days and in 4 of 10 treated with 4000 U/kg/h for 4 days. Only thrombi younger than 8 days could be lysed, with 61% (8/13) rate of lysis for thrombi less than 5 days old. Bleeding complications were observed more frequently with the higher doses and longer durations of therapy. The four treatment regimens all induced dose-dependent changes in fibrinogen, fibrin(ogen) degradation products, plasminogen and antiplasmin. Neither pre- nor postinfusion values of these parameters could differentiate patients with lysis from those without lysis. It is concluded that UK can provoke a high rate of thrombolysis of DVT treated early after the appearance of symptoms but that there is no relationship between UK-induced modifications of fibrinolysis and the outcome of therapy.
