Objective: Current guidelines recommend utilization of catheter-directed thrombolysis systems for management of patients with submassive pulmonary embolism (PE) who have relative contraindications to systemic thrombolysis. Evidence from previous trials have demonstrated the short-term efficacy and safety of one of these systems, the EkoSonic Endovascular System (EKOS). The objective of this study was to evaluate the long-term efficacy and safety of EKOS in submassive PE. 

Methods: This single-center, retrospective study evaluated subjects ≥18 years old with submassive PE and baseline right ventricular to left ventricular (RV/LV) diameter ratio ≥1. The primary outcome evaluated change in RV/LV diameter ratio from baseline to first follow-up. The secondary outcomes evaluated need for further intervention after EKOS, major bleeding within 72 hours and 6 months, all-cause mortality at 6 months, and all-cause 30-day readmission rate. 

Results: Overall, 41 subjects received EKOS for submassive PE. Of the 26 subjects evaluated for the primary outcome, the RV/LV diameter ratio decreased by an average of 0.56 (P < 0.05). Of the 41 subjects evaluated for the secondary outcomes, 1 subject required pulmonary embolectomy after EKOS intervention, 1 major bleed occurred within 72 hours, 1 major bleed occurred within 6 months, 1 subject died within 6 months, and 3 subjects were readmitted within 30 days. 

Conclusions: Intervention with EKOS further reduced right heart strain and resulted in few complications compared with previous trials providing evidence that EKOS is effective and safe long-term for management of submassive PE. Use should be considered in patients with relative contraindications to systemic thrombolytic therapy.