Systemic thrombolysis increases hemorrhagic stroke risk without survival benefit compared with catheter-directed intervention for the treatment of acute pulmonary embolism

Abstract

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 (NIS) from 2009 to 2012. Comorbidities, clinical characteristics, and invasive procedures were identified using International Classification of Diseases, Ninth Revision (ICD) 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 those of 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 had 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, 1430 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 with ST (odds ratio, 0.47; 95% confidence interval, 0.27-0.82; P = .01). Subgroup analysis showed decreased odds of hemorrhagic stroke for CDI in the nonshock subgroup and increased procedural bleeding for CDI but no difference in hemorrhagic stroke risk in the shock subgroup.

Conclusions: ST for acute PE may not improve in-hospital mortality compared with CDI but increases the overall risk of hemorrhagic stroke compared with CDI. Further prospective studies should examine the comparative effectiveness and safety of these two treatments.

Figure 1. Matched In-Hospital Mortality

OR: odds ratio. CI: confidence interval. ST: systemic thrombolysis. CDI: catheter-directed intervention. ST and CDI columns are mortalities/total cohort (N%).

Figure 2. Matched Secondary Outcomes

OR: odds ratio. CI: confidence interval. ST: systemic thrombolysis. CDI: catheter-directed intervention. ST and CDI columns are events/total cohort (N%)