Background
Systemic thrombolysis (ST) and catheter-directed intervention (CDI) are both used in the treatment of acute pulmonary embolism (PE), but the comparative outcomes of these two therapies remain unclear. The objective of this study was to compare short-term mortality and safety outcomes between the two treatments using a large national database.
Methods
Patients presenting with acute PE were identified in the National Inpatient Sample from 2009–2012. Comorbidities, clinical characteristics, and invasive procedures were identified using International Classification of Diseases version 9 (ICD-9) codes and the Elixhauser comorbidity index. To adjust for anticipated baseline differences between the two treatment groups, propensity score matching was used to create a matched ST cohort with clinical and comorbid characteristics similar to the CDI cohort. Subgroups of patients with and without hemodynamic shock were analyzed separately. Primary outcomes were in-hospital mortality, overall bleeding risk, and hemorrhagic stroke risk.
Results
Of 263,955 subjects with acute PE, 1.63% (n=4272) received ST and 0.55% (n=1455) received CDI. ST subjects were older, had more chronic comorbidities, and higher rates of respiratory failure (ST: 27.9%, n=1192; CDI: 21.2%, n=308; P<.001) and shock (ST: 18.2%, n=779; CDI: 12%, n=174; P<.001). CDI subjects had higher rates of concurrent deep venous thrombosis (ST: 35.8%, n=1530; CDI 45.9%, n=668; P<.001) and vena cava filter placement (ST: 31.1%, n=1328; CDI: 57%, n=830; P<.001). In the unmatched cohort, ST subjects had higher in-hospital mortality (ST: 16.7%, n=714; CDI: 9.4%, n=136, P<.001) and hemorrhagic stroke rates (ST: 2.2%, n=96; CDI: 1.4%, n=20; P=.041). After propensity matching, 1434 patients remained in each cohort; baseline characteristics of the matched cohorts did not differ significantly using standardized difference comparisons. Analysis of the matched cohorts did not demonstrate a significant effect of CDI on in-hospital mortality or overall bleeding risk but did show a significant protective effect against hemorrhagic stroke compared to ST (OR 0.47, 95% CI 0.27–0.82, P=.01). Subgroup analysis showed decreased odds of hemorrhagic stroke for CDI in the non-shock subgroup, and increased procedural bleeding for CDI but no difference in hemorrhagic stroke risk in the shock subgroup.
Conclusions
Systemic thrombolysis for acute pulmonary embolism may not improve in-hospital mortality compared to CDI but increases the overall risk of hemorrhagic stroke compared to catheter-directed intervention. Further prospective studies should examine the comparative effectiveness and safety of these two treatments.