Why is this study important?

Despite 12 years of endovascular therapy for treatment of pulmonary embolism and the presence of seven FDA-approved devices on the market, there is little randomized controlled trial data to support an endovascular approach over anticoagulation (AC) alone.

What question was this study supposed to answer?

STORM PE randomized catheter-assisted vacuum thrombectomy (CAVT) with AC versus AC alone, with a primary endpoint of the change in RV/LV ratio at 48 hours. The trial was powered with an assumed ratio difference RV/LV of 0.25 between the two arms. Major adverse events (MAE) were also reported, including clinical deterioration requiring rescue therapy, PE-related mortality, symptomatic recurrent PE, and major bleeding.

What did the study show?

One hundred patients were enrolled (47 CAVT, 53 AC). For the primary endpoint, CAVT achieved a 2.3X greater reduction in RV/LV ratio than AC at 48 hours. Additionally, significantly more patients in the CAVT arm achieved a significant improvement in RV/LV ratio, defined as a reduction > 0.2 (78.3% vs 51.9%), and significantly more had normalization of the RV/LV ratio (39.1% vs. 13.5%). There was no significant difference in major adverse events (MAE) between the two arms. 

Key Insight

The positive results of STORM PE affirm the practice of CAVT and AC over AC alone. Though it was not powered for hard endpoints such as mortality, nor was it a long-term outcomes study, it is nonetheless strongly supportive of CAVT first, given the large improvement in the RV/LV ratio without any signal of an increase in MAE. This trial supports the continued practice of a primary approach of CAVT with AC for intermediate to high-risk PE patients and hopefully sets the stage for larger trials to examine hard clinical endpoints and long-term outcomes.