Low-dose thrombolytic therapy versus unfractionated heparin in patients with intermediate-high risk pulmonary embolism.

Background: Patients with intermediate-high risk pulmonary embolism (PE) who have acute right ventricular dysfunction and myocardial injury without overt hemodynamic compromise may be candidates for thrombolytic therapy (TT). In this study, we aimed to compare the clinical outcomes of low-dose prolonged TT and unfractionated heparin (UFH) in intermediate-high risk PE patients.

Methods: This study enrolled 83 (female: 45 [54.2%], mean age: 70.07±10.7 years) retrospectively evaluated patients with the diagnosis of acute PE who were treated with low-dose and slow-infusion of TT or UFH. The primary outcomes of the study were de-fined as a combination of death from any cause and hemodynamic decompensation, and severe or life-threatening bleeding. Secondary endpoints were recurrent PE, pulmonary hypertension, and moderate bleeding.

Results: The initial management strategy of intermediate-high risk PE was TT in 41 (49.4%) patients and UFH in 42 (50.6%) cases. Low-dose prolonged TT was successful in all patients. While the frequency of hypotension decreased significantly after TT (22 vs. 0%, P<0.001), it did not decrease after UFH (2.4 vs. 7.1%, p=0.625). The proportion of hemodynamic decompensation was significantly lower in the TT group (0 vs. 11.9%, p=0.029). The rate of secondary endpoints was significantly higher in the UFH group (2.4 vs. 19%, P=0.016). Moreover, the prevalence of pulmonary hypertension was significantly higher in UFH group (0 vs. 19%, p=0.003).

Conclusion: Prolonged TT regimen with low dose, slow infusion of tissue plasminogen activator was found to be associated with a lower risk of hemodynamic decompensation and pulmonary hypertension in patients with acute intermediate-high-risk PE compared to UFH.