STORM-PE: Mechanical Thrombectomy in Intermediate-High-Risk Pulmonary Embolism

Acute pulmonary embolism (PE) remains a major public health challenge, with approximately 600,000 symptomatic cases and 200,000 related deaths annually in the United States. Among patients with intermediate-high-risk PE, right ventricular (RV) strain is a critical predictor of poor outcomes, doubling the risk of 30-day mortality. While therapeutic anticoagulation (AC) is the established standard of care, there is growing interest in mechanical approaches to rapidly relieve RV strain and improve patient outcomes.

Single-arm studies such as EXTRACT-PE and the ongoing STRIKE-PE trial have demonstrated that computer-assisted vacuum thrombectomy (CAVT) with the Indigo Aspiration System can significantly reduce RV/LV ratio, with early results showing low major adverse event (MAE) rates and improvements in quality of life. Yet, without head-to-head randomized data, its place in frontline therapy remains uncertain.

A Look at STORM-PE

STORM-PE is the first randomized trial to directly compare AC alone to AC plus CAVT in patients with intermediate-high-risk PE. This risk group is defined by a RV/LV ratio of 1.0 or more on CT pulmonary angiography (CTPA) and elevated cardiac biomarkers, without overt hemodynamic instability. The trial will enroll up to 100 patients across approximately 25 international sites, with treatment allocation stratified by center.

The primary endpoint is the change in RV/LV ratio at 48 hours, assessed by a blinded core laboratory. Secondary outcomes include MAEs at 7 days, symptomatic PE recurrence, mortality, and validated functional and quality of life metrics measured through 90 days.

Patient recovery will also be monitored using wearable devices that capture physical activity, sleep, and vital signs post-discharge.

Methodology and Statistical Considerations

The trial employs a 1:1 randomization scheme and open-label design with blinded endpoint adjudication. It is powered to detect a 0.25 difference in RV/LV ratio reduction between treatment arms. Analyses will be conducted on both intent-to-treat and per-protocol populations, with subgroup assessments by demographic and disease severity.

A t-test with 1-sided alpha of 0.025 will assess the null hypothesis. Secondary endpoints will be analyzed descriptively with 95 percent confidence intervals.

Implications for Practice and Research

STORM-PE addresses several key evidence gaps in PE management:

• First head-to-head trial comparing AC alone to AC plus CAVT with Indigo Aspiration System in intermediate-high-risk patients
• Incorporates patient-centered outcomes such as functional and quality of life assessments
• Extends follow-up to 90 days, providing insights into both short- and long-term safety and efficacy
• Uses wearable technology to track recovery metrics, offering a unique view of post-discharge progress

If positive, STORM-PE could shift practice patterns by supporting earlier use of mechanical thrombectomy in carefully selected patients. Conversely, if outcomes are similar between arms, it would validate the current standard of care, ensuring that invasive interventions remain reserved for the sickest patients.

Reference:
Rosovsky RP, Konstantinides SV, Moriarty JM, et al. A prospective, multicenter, randomized controlled trial evaluating anticoagulation alone vs anticoagulation plus computer assisted vacuum thrombectomy for the treatment of intermediate-high-risk acute pulmonary embolism: Rationale and design of the STORM-PE study. Am Heart J. 2025;288:1-14. doi:10.1016/j.ahj.2025.03.018