Objective: To assess the change of pulmonary perfusion after thrombolytic therapy in patients with acute pulmonary embolism.
Methods: Eighty patients with acute pulmonary embolism received pulmonary radionuclide perfusion imaging before and after thrombolytic therapy. Percentage of perfusion defect scores (PPDs) was calculated by semiquantitative analysis of pulmonary perfusion imaging before thrombolytic therapy (PPDsD(0)), 1 - 5 days (PPDsD(5)), 6 - 30 days (PPDsD(30)) and 3 months after thrombolytic therapy (PPDsM(3)).
Results: The mean PPDsD(0) of the 80 patients was (57.3 +/- 16.4)%. In 64 of the 80 patients, mean PPDsD(0) and PPDsD(5) were (55.5 +/- 16.8)% and (40.0 +/- 18.6)% respectively (P < 0.001). In 30 of these 64 patients, mean PPDsD(0), PPDsD(5) and PPDsD(30) were (57.5 +/- 16.1)%, (39.3 +/- 16.8)% and (29.5 +/- 17.3)% respectively. Differences between these 3 mean PPDs values were highly significant (all P < 0.001). In 11 of the 80 patients, mean PPDsD(30) and PPDsM(3) were (40.9 +/- 18.1)% and (29.1 +/- 27.1)% respectively (P < 0.05). In two groups of patients with the courses of disease in 7 days and in 8 - 14 days respectively, significant differences were found between PPDsD(0) and PPDsD(5) (P < 0.001, P < 0.001 respectively), and between PPDsD(0) and PPDsD(30) (P < 0.001, P < 0.005 respectively). The difference was also significant, although to a lesser degree (P < 0.05) between these values in a group of patients with the course of disease beyond 14 days.
Conclusion: This study suggests that radionuclide pulmonary perfusion imaging is a reliable method for evaluating the changes of pulmonary perfusion before and after thrombolytic therapy in patients with acute pulmonary embolism.