Comparison of In-Hospital Outcomes and Readmission Rates in Acute Pulmonary Embolism Between Systemic and Catheter-Directed Thrombolysis (from the National Readmission Database): Arora S, Panaich SS, Ainani N, et al. Am J Cardiol. 2017;120(9):1653-1661

Abstract

Current guidelines recommend treatment with systemic thrombolysis for patients with pulmonary embolism (PE) that are hemodynamically unstable, with weaker recommendations for those with submassive PE resulting in right ventricular dysfunction or myocardial injury. Systemic thrombolysis comes with the risk of major bleeding including gastrointestinal and intracranial hemorrhage. Catheter-Directed Thrombolysis (CDT) may provide a solution to this problem by targeting the therapy directly at the thrombus as opposed to delivering the therapy systemically, resulting in lower total delivered dosages and potentially lesser bleeding risk. The goal of this study was to compare the in-hospital mortality, bleeding complications and 30-day readmission rates between patients treated for PE with systemic thrombolysis and CDT. Data was gathered from 2013-2014 using the National Readmission Database (NRD), a multicenter database that comprises 49.3% of all hospitalizations in the United States. The subjects included were at least 18 years old and were identified through an electronic search of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes for PE, thrombolysis and CDT. Propensity score matching was used to compare subjects with similar demographics and co-morbidities who received either systemic thrombolytics (n=2,256) or CDT (n=1,128). The co-primary outcomes were in-hospital mortality and 30-day readmission rates and the secondary outcome was combined in-hospital mortality + gastrointestinal (GI) bleed + intracranial hemorrhage. In-hospital mortality was lower in the CDT cohort (6.12%) than the systemic thrombolytics cohort (14.94%) (Odds Ratio [OR] 0.37, 95% Confidence Interval [CI] 0.28-0.49). Patients who received CDT also had a lower composite secondary outcome (in-hospital mortality + GI bleed +intracranial hemorrhage) of 8.42% versus 18.13% in those who received systemic thrombolysis (OR 0.41, 95% CI 0.33-0.53). The CDT cohort also had a lower 30-day readmission rate compared to those who received systemic thrombolysis (7.65% versus 10.58%, OR 0.70, 95% CI 0.54-0.92). The authors concluded that treatment for PE with CDT resulted in improved mortality, fewer bleeding complications, and lower readmission rates than systemic thrombolysis. They theorize that CDT was more effective at clot removal due to direct administration of thrombolytics at the intended target, while the better safety profile was attributed to lower doses of thrombolytics administered during CDT with reduced systemic reabsorption. Comment: This retrospective trial is the largest study to date comparing outcomes between CDT and systemic thrombolytics in the treatment of PE. The mortality and readmission rates favoring CDT are compelling, as well as the decrease bleeding rates. The authors attempted to control for bias by using propensity score matching, however, they lacked data regarding the details of the individual cases, the thrombolytic agents that were administered and their doses. Additionally, they were not able to control for illness severity which may bias the results as more unstable patients may have been more likely to receive systemic thrombolysis as opposed to procedural CDT.