TCT 2025: STORM-PE Trial Demonstrates Safety and Efficacy of Mechanical Thrombectomy in Intermediate-High-Risk Pulmonary Embolism

This news is covered by the Medical Dialogues Bureau present at the TCT Conference 2025, being held in San Francisco, USA.

The STORM-PE randomized controlled trial, presented at TCT 2025, demonstrated that computer-assisted vacuum thrombectomy combined with anticoagulation (CAVT) achieved a significantly greater improvement in right ventricular function compared with anticoagulation (AC) alone in patients with acute intermediate-high risk pulmonary embolism (PE).

The findings, presented by Dr. Robert Lookstein of Mount Sinai Health System, mark the first randomized trial in more than a decade to compare mechanical thrombectomy with standard anticoagulation for acute PE.

The trial was designed to evaluate the safety and efficacy of mechanical thrombectomy in addition to anticoagulation versus anticoagulation alone. Previous studies of catheter-directed therapies lacked randomized evidence, making STORM-PE the first completed RCT directly comparing these approaches. Eligible patients had acute PE confirmed by CT pulmonary angiography (CTPA) within 14 days, an elevated right ventricular to left ventricular (RV/LV) ratio of ≥1.0, and positive cardiac biomarkers. Those with hemodynamic instability or chronic thromboembolic disease were excluded.

Between July 2023 and June 2025, 100 patients were randomized across 19 sites to either CAVT plus anticoagulation (n=47) or anticoagulation alone (n=53). The primary efficacy endpoint was change in RV/LV ratio at 48 hours, assessed by an independent, blinded core laboratory. The primary safety endpoint was the incidence of major adverse events (MAEs) within seven days, including clinical deterioration, PE-related mortality, recurrent PE, or major bleeding.

At 48 hours, the mean RV/LV ratio decreased from 1.63 to 1.11 in the CAVT arm versus 1.56 to 1.32 in the AC arm, showing a significantly greater improvement with thrombectomy (absolute reduction 0.52 ± 0.37 vs 0.24 ± 0.40; p < 0.001). The between-group difference in reduction was 0.27 (95% CI, 0.12–0.43). A clinically meaningful reduction in RV strain (>0.2) was achieved in 78.3% of patients in the CAVT group versus 51.9% in the AC group (p = 0.011), and a normalized RV/LV ratio (≤1.0) was observed in 39.1% vs 13.5%, respectively (p = 0.005).

Safety outcomes were comparable between groups. The composite seven-day MAE rate was 4.3% in the CAVT arm and 7.5% in the AC arm (p = 0.681). There were two PE-related deaths in the CAVT group, both adjudicated as not device- or procedure-related, and no such events in the AC arm. Major bleeding occurred in one patient in each group (2.1% vs 1.9%), with no access-site complications or device-related transfusions reported.

Procedurally, thrombectomy was technically successful in all 47 patients, with a median thrombectomy time of 25 minutes and mean reductions of 10.8 mm Hg in systolic and 8.2 mm Hg in mean pulmonary artery pressures. Operators across the 19 centers completed the study after limited prior experience with the Lightning Flash system, underscoring ease of device use and reproducibility.

The STORM-PE trial established that mechanical thrombectomy using CAVT plus anticoagulation produces a superior reduction in RV/LV ratio compared with anticoagulation alone, with a similar safety profile and no device- or procedure-related complications. These results reinforce the role of mechanical thrombectomy as a safe and effective treatment strategy for patients with acute intermediate-high risk PE, addressing a key evidence gap in pulmonary embolism management.

Reference: Robert Lookstein et al., Randomized Controlled Trial of Mechanical Thrombectomy with Anticoagulation Versus Anticoagulation Alone for Acute Intermediate High Risk Pulmonary Embolism: Primary Results from STORM – PE, TCT Conference 2025, San Francisco.
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