Impact of Thrombolytic Therapy on the Long-Term Outcome of Intermediate-Risk Pulmonary Embolism

Background The long-term effect of thrombolytic treatment of pulmonary embolism (PE) is unknown. Objectives This study investigated the long-term prognosis of patients with intermediate-risk PE and the effect of thrombolytic treatment on the persistence of symptoms or the development of late complications. Methods The PEITHO (Pulmonary Embolism Thrombolysis) trial was a randomized (1:1) comparison of thrombolysis with tenecteplase versus placebo in normotensive patients with acute PE, right ventricular (RV) dysfunction on imaging, and a positive cardiac troponin test result. Both treatment arms received standard anticoagulation. Long-term follow-up was included in the third protocol amendment; 28 sites randomizing 709 of the 1,006 patients participated. Results Long-term (median 37.8 months) survival was assessed in 353 of 359 (98.3%) patients in the thrombolysis arm and in 343 of 350 (98.0%) in the placebo arm. Overall mortality rates were 20.3% and 18.0%, respectively (p = 0.43). Between day 30 and long-term follow-up, 65 deaths occurred in the thrombolysis arm and 53 occurred in the placebo arm. At follow-up examination of survivors, persistent dyspnea (mostly mild) or functional limitation was reported by 36.0% versus 30.1% of the patients (p = 0.23). Echocardiography (performed in 144 and 146 patients randomized to thrombolysis and placebo, respectively) did not reveal significant differences in residual pulmonary hypertension or RV dysfunction. Chronic thromboembolic pulmonary hypertension (CTEPH) was confirmed in 4 (2.1%) versus 6 (3.2%) cases (p = 0.79). Conclusions Approximately 33% of patients report some degree of persistent functional limitation after intermediate-risk PE, but CTEPH is infrequent. Thrombolytic treatment did not affect long-term mortality rates, and it did not appear to reduce residual dyspnea or RV dysfunction in these patients.