Why is this study important? 

The Ekosonic Endovascular System (EKOS) was FDA-approved in 2004 for performance of Ultrasound-Facilitated Catheter-Directed Thrombolysis (USCDT). There have been encouraging studies showing significant improvements in surrogate markers and reasonable safety, but efficacy data have been lacking. As a result, widespread adoption has not occurred, and guidelines have given only level 2 recommendations. Therefore, an adequately powered clinical outcomes trial has been greatly needed. 

What question was this study supposed to answer?

HI-PEITHO was a multinational, multicenter, open-label, parallel-group comparison trial with blinded primary outcome adjudication. USDCT was compared to standard therapy with anticoagulation alone for the treatment of Intermediate-risk pulmonary embolism patients. The primary outcome was highly clinically relevant: a 7-day composite of PE-related mortality, cardiorespiratory decompensation, or PE recurrence. 

What did the study show?

The study was positive with the incidence of the Composite Primacy Outcome in the USDCT arm being 4.0% and the anticoagulation arm 10.3% (RR 0.39; p=0.005). The rate of major bleeding was not statistically different between the two arms. ​

Key insights:

This is the first randomized trial demonstrating an advantage of catheter-directed therapy in the care of patients with intermediate-risk PE. The trial will likely have an immediate impact on treatment patterns given the current widespread variability in practice. What remains unknown is the efficacy of other catheter-based therapies, such as thrombectomy, or the relative efficacy of thrombectomy vs. USDCT. Hopefully, future trials will address these questions and potentially allow intervention to be tailored to patient and operator characteristics.