Abstract Body (Do not enter title and authors here): Introduction
High-risk pulmonary embolism (PE), defined as acute PE with associated hemodynamic instability, is a life-threatening condition with in-hospital mortality rates of up to 40%. Catheter-directed thrombolysis (CDT) and mechanical thrombectomy (MT) are two minimally invasive techniques used in PE to reduce clot burden and restore pulmonary circulation, but data comparing the two are limited in high-risk PE.

Research Question
What are the differences in safety outcomes and hospital costs between CDT and MT in patients with high-risk PE?

Methods
Utilizing the National Inpatient Sample from 2018-2021, we identified patients hospitalized with high-risk PE, defined International Classification of Disease, 10^th Revision codes for PE and either vasopressor use or mechanical circulatory support. Patients with procedure codes for CDT or MT were selected for this study. Patients under the age of 18 or who received both procedures were excluded. Patients were stratified by treatment modality, and propensity score matching was done in a 1:1 fashion to account for differences in baseline characteristics. Multivariate regression models were used to assess differences in in-hospital mortality, length of hospitalization, total hospitalization cost, and adverse outcomes.

Results
A total of 880 patients were in the CDT cohort and 1140 in the MT cohort. After matching, 710 patients remained in each group. No difference in in-hospital mortality was observed (38.0% vs 37.3%; OR 1.02, p = 0.853). The MT cohort had higher total cost ($71689 [$40638–$156344] vs $53216 [$29848–$97989], p < 0.001) and length of stay (9.0 [4.0–20.0] days vs 8.0 [3.0–14.0] days, p < 0.001). Additionally, the MT cohort had a higher incidence of intracranial hemorrhage (4.2% vs 2.1%, OR 1.93, p = 0.041) and cerebrovascular accident (4.9% vs 2.8%, OR 1.85, p = 0.038), but lower incidence of vascular complications (7.7% vs 10.6%, OR 0.66, p = 0.026)

Conclusion
Among high-risk PE patients requiring vasopressor support or mechanical circulatory support, CDT and MT had comparable rates of in-hospital mortality. CDT was associated with lower hospital costs with increased risk for vascular complications but decreased risk of intracranial hemorrhage and cerebrovascular accident, suggesting it may be more cost effective than MT.