Therapy with streptokinase and urokinase induce effective thrombolysis but may be
complicated by hemorrhagic side effects. In order to minimize these complications
single-chain urokinase-type plasminogen activator (scu-PA) was given in patients with
acute transmural myocardial infarction at three different dosage regimens consecutively
in combination with heparin. In a first group four patients received 15 mg, thirteen
48 mg (group II) and five 72 mg (group III) of scu-PA intravenously. In 22 cases detailed
clotting analyses could be performed. Results: The coagulation analysis demonstrated
a reduction of the fibrinogen concentration by 11 % in group I, 17 % in group II and
44 % in group III. Plasminogen decreased by 9 % in the first, 43 % in the second and
61 % in the third group. The level of∝2-anti-plasmin showed a reduction of 12 % in
group I, 48 % in group II and 80 % in group III. Fibrin degradation products increased
in all groups. The euglobulin clot lysis time was moderately shortened in group I
but significantly in the groups II and III. Reptilase and thrombin coagulase time
were prolonged moderately. Thrombin clotting time and aPTT could be attained at therapeutic
range by additional application of heparin. Antithrombin III showed no alteration.
Thrombolysis could be achieved in none of the patients in group I but with good results
in group II and III.
Our data suggest that intravenous application of scu-PA at a dosage of 48 mg is able
to induce effective thrombolysis with only slight destruction of fibrinogen. At higher
dosages a further increased rate of thrombolysis may be possible but also a higher
rate of fibrinogenolysis may be considered.
