Thrombolytic therapy and outcome of patients with an acute symptomatic pulmonary embolism

BACKGROUND: While the primary therapy for most patients with a pulmonary embolism (PE) consists of anticoagulation, the efficacy of thrombolysis relative to standard therapy remains unclear. METHODS: In this retrospective cohort study of 15,944 patients with an objectively confirmed symptomatic acute PE, identified from the multicenter, international, prospective, Registro Informatizado de la Enfermedad TromboEmb\uf3lica (RIETE registry), we aimed to assess the association between thrombolytic therapy and all-cause mortality during the first 3 months after the diagnosis of a PE. After creating two subgroups, stratified by systolic blood pressure (SBP) (< 100 mm Hg vs. other), we used propensity score-matching for a comparison of patients who received thrombolysis to those who did not in each subgroup. RESULTS: Patients who received thrombolysis were younger, had fewer comorbid diseases and more signs of clinical severity compared with those who did not receive it. In the subgroup with systolic hypotension, analysis of propensity score-matched pairs (n = 94 pairs) showed a non-statistically significant but clinically relevant lower risk of death for thrombolysis compared with no thrombolysis (odds ratio [OR] 0.72; 95% confidence interval [CI], 0.36-1.46; P = 0.37). In the normotensive subgroup, analysis of propensity score-matched pairs (n = 217 pairs) showed a statistically significant and clinically meaningful increased risk of death for thrombolysis compared with no thrombolysis (OR 2.32; 95% CI, 1.15-4.68; P = 0.018). When we imputed data for missing values for echocardiography and troponin tests in the group of normotensive patients, we no longer detected the increased risk of death associated with thrombolytic therapy. CONCLUSIONS: In normotensive patients with acute symptomatic PE, thrombolytic therapy is associated with a higher risk of death than no thrombolytic therapy. In hemodynamically unstable patients, thrombolytic therapy is possibly associated with a lower risk of death than no thrombolytic therapy. However, study design limitations do not imply a causal relationship between thrombolytics and outcome