Our results demonstrate that repeat thrombolysis is successful without adverse outcomes in only 31% of patients. It has previously been reported that thrombolysis is more effective in PE patients who have had a relatively short duration of symptoms. There is an inverse association between duration of symptoms and improvement of pulmonary vascular reperfusion after thrombolysis. Although delay attenuates efficacy, thrombolysis was reported in this study to be still useful in patients who had experienced symptoms for 6 to 14 days. In our study, approximately one third of the patients had clinical symptoms dating from 6 to 14 days previously. Furthermore, it is interesting to note that four of the five PE-related deaths in the repeat-thrombolysis group were in patients whose first symptoms had appeared > 6 days prior to treatment. In addition, we cannot exclude the possibility that asymptomatic (silent) PE preceded the onset of clinical symptoms. Hence, failed thrombolysis may be related to prior PEs > 14 days old, for which this treatment is less effective.
It is unlikely that antecedents of streptococcal infections, and thereby, the presence of streptococcal antibodies, were directly responsible for any negative effect on the efficacy of streptokinase. The fact that all patients had a fibrinogen level of < 1 g/L proves that streptokinase was effective. Source
We did not observe any more episodes of bleeding in patients in the repeat-thrombolysis group than in those in the surgically treated group. Similarly, there was no significant difference in the rate of intracranial hemorrhage between the two treatment groups. Data from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries 1 study showed that repeat thrombolysis for the treatment of early reinfarction was associated with an increased risk of intracranial hemorrhage. On the other hand, the Assessment of the Safety and Efficacy of a New Thrombolytic 2 trial did not find any difference in hemorrhagic stroke in the same indication. While our study did not show any significant difference in major bleeding, this result is hard to interpret given the small sample size.