Treatment of Pulmonary Embolism with Urokinase Results of Clinical Trial (Phase 1)

THE RECENTLY completed, randomized, multi-institutional Urokinase-Pulmonary Embolism Trial, previously described on these pages,1 has demonstrated that a 12-hour infusion of urokinase followed by heparin therapy accelerates the resolution of pulmonary embolism within 24 hours, when compared to heparin therapy alone. This treatment effect favoring urokinase was established by statistically significant differences in 24-hour pulmonary arteriograms, lung scans, and hemodynamic measurements. The treatment difference was noted first in the arteriograms, then with the hemodynamic measurements, and finally in the lung scans. A summary of these findings is shown in table 1. A more detailed report has been submitted to the Journal of the American Medical Association.2 At the conclusion of the trial, 160 patients were studied with a 2-week mortality of 9% in the heparin-treated patients and 7% in the urokinase group. Recurrent pulmonary embolism during this period occurred in 19% and 15% of patients, respectively. Pulmonary embolectomy was not performed in any of these patients. The difference in lung scan resolution between urokinase and heparin-treated patients disappeared by the seventh post-treatment day, but in both treatment groups an average of 25% of the original scan defect remained on follow-up scans at 1 year in the 59 patients on whom these data are presently