Urokinase-streptokinase embolism trial. Phase 2 results. A cooperative study

One hundred sixty-seven patients with angiographically demonstrated pulmonary emboli were randomized to treatment with 12 hours of urokinase, 24 hours of urokinase, or 24 hours of streptokinase in this second phase of the study of thrombolytic treatment in pulmonary embolism. Resolution of thromboemboli was determined by pulmonary angiograms, lung scans, and hemodynamics. The clot resolution with 24 hours of urokinase was equal to that with 12 hours of urokinase therapy. Twenty-four hours of urokinase therapy resulted in greater improvement than streptokinase therapy; this was seen in scans, but not in angiograms. In massive embolism, this difference was statistically significant. Hemodynamic differences varied. There was no significant difference in mortality. Drug-related morbidity was minimal. All three regimens are more effective in accelerating resolution of pulmonary thromboemboli than heparin sodium alone was in the phase 1 trial. (JAMA229:1606-1613, 1974)