Abstract
A life-threatening thrombus in massive pulmonary embolism has to be eliminated within minutes. Extremely activated plasmatic fibrinolysis destroys such thrombi in time: 50 µL plasma clots were incubated with urokinase or tissue-type plasminogen activator and 50 µL pooled normal plasma. The microtiter plate clot lysis assay was performed. The time point at which 50% of the clot has been lysed is 4 minutes for 8333 IU/mL urokinase or an equimolar concentration of tissue-type plasminogen activator (52498 IU/mL = 105 µg/mL). The effective dose 50% at 5 minutes lysis time is about 800 nM (4320 IU/mL) urokinase or (27220 IU/mL = 54 µg/mL) tissue-type plasminogen activator. Addition of plasminogen to the plasmatic clot supernatant improves thrombolysis if 65 IU/mL of urokinase acts for 10 minutes. The risk for severe intracranial hemorrhage in massive thrombolysis might be much lower than the lethality of a massive pulmonary embolism. Extremely activated plasmatic thrombolysis could be clinically indicated.