Blood coagulation changes during effective thrombolysis using urokinase and heparin.

The efficacy and the safety of a new urokinase dosage regimen (loading dose 250,000 IU, initial maintenance dosage 2,000 IU/kg/h in combination with heparin) was studied in ten cases of deep vein thrombosis with regard to the changes of the blood coagulation and fibrinolytic enzyme system. The coagulation analyses demonstrated a pronounced activation of the fibrinolytic system with a statistically significant (p less than 0.05) shortening of the euglobulin clot lysis time and increase of the FDP. The fibrinogen concentration ranged from 50-100 mg/dl already after 12-36 hours. Plasminogen was reduced by 63%, alpha 2-macroglobulin by 32% and factor VIII:C by 42% (p less than 0.05 each). The decrease of fibrinogen (Clauss method) related well to the method of Ratnoff and Menzie, the reduction of plasminogen and the shortening of the euglobulin clot lysis time. According to our data, a sufficient plasma fibrinogenolytic activity may permit on its own an assessment of an adequate therapy with urokinase and the requirements of dose adjustment. The dosage regimen applied here proved effective and readily controllable. Relevant side reactions were not observed.