Randomized Controlled Trial of Mechanical Thrombectomy With Anticoagulation Versus Anticoagulation Alone for Acute Intermediate-High Risk Pulmonary Embolism: Primary Outcomes From the STORM-PE Trial
Key result
CAVT plus anticoagulation reduces 48-hour RV/LV ratio by ~0.27 versus anticoagulation alone.
Why the study?
Patients with intermediate-high risk PE are at risk of early decompensation and mortality, but randomized controlled trial data evaluating the efficacy and safety of mechanical thrombectomy compared with anticoagulation alone were lacking.
Does computer-assisted vacuum thrombectomy with anticoagulation reduce RV/LV ratio at 48 hours in adults with acute intermediate-high risk pulmonary embolism compared to anticoagulation alone?
Study Design
Type
RCT (n=100)
Blinding
Blinded outcome assessment
Randomization
1:1
Multicenter
Yes
Structured PICO
Does computer-assisted vacuum thrombectomy with anticoagulation reduce RV/LV ratio at 48 hours in adults with acute intermediate-high risk pulmonary embolism compared to anticoagulation alone?
P
Population
100 adults with acute intermediate-high risk pulmonary embolism, normotension, RV/LV ratio ≥1.0, and elevated cardiac biomarkers, assessed at 48 hours.
I
Intervention
Computer-assisted vacuum thrombectomy (CAVT) with the Indigo Aspiration System plus anticoagulation
C
Comparator
Anticoagulation alone
O
Outcome
Change in RV/LV ratio at 48 hours, assessed by a blinded independent imaging core laboratorysurrogate
Main Result
Mean Difference: 0.27 (95% CI 0.12–0.43)
Absolute Event Rate: 0.52% vs 0.24%
p-value: p=<0.001
In patients with intermediate-high risk pulmonary embolism, computer-assisted vacuum thrombectomy combined with anticoagulation significantly reduced RV/LV ratio at 48 hours compared to anticoagulation alone, without increasing major adverse events.
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Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“What distinguishes STORM‑PE from prior studies is its deliberate focus on recovery beyond early physiologic improvement. Functional endpoints are critical because they capture outcomes that are most meaningful to patients.”
“The CAVT is mechanical tech from Penumbra, used to remove blood clots from arteries and veins. What makes it unique is that it's a minimally invasive procedure, and it uses a computer-powered algorithm to enable it to quickly detect what is clot and what's not and then remove the clot and minimize blood loss. And in our study, we found that it was a safe and fast procedure.”
“The field of interventional therapies for acute PE has really expanded rapidly in the last 10 years, but there has not been a randomized controlled trial evaluating any minimally invasive therapy since 2013, so many of us in the interventional space felt that there was a need to establish core data to move the field forward, and that's what STORM-PE was about. We found the addition of the thrombectomy procedure in a statistically significant way dramatically reduced the strain on the right heart as compared to anticoagulation alone.”
Implication
Mechanical thrombectomy may accelerate early RV/LV normalization in intermediate-high-risk PE; leaves open effects on clinical outcomes.
Abstract
BACKGROUND: Patients with intermediate-high risk pulmonary embolism (PE) have an elevated right ventricular (RV) to left ventricular (LV) diameter ratio and are at risk of early clinical decompensation and mortality. Reperfusion therapy aims to rapidly relieve acute RV pressure overload and to normalize hemodynamics. STORM-PE (A Prospective, Multicenter, Randomized Controlled Trial Evaluating Anticoagulation Alone Versus Anticoagulation Plus Mechanical Aspiration With the Indigo Aspiration System for the Treatment of Intermediate-High Risk Acute Pulmonary Embolism) is the first reported randomized controlled trial to test the efficacy and to evaluate the safety of mechanical thrombectomy, specifically computer-assisted vacuum thrombectomy (CAVT) with anticoagulation compared to anticoagulation alone. METHODS: STORM-PE is an international randomized controlled trial with 1:1 randomization to CAVT with anticoagulation or anticoagulation alone. Eligible adults had acute-onset (symptoms ≤14 days), intermediate-high risk PE and were normotensive, with an RV/LV ratio ≥1.0 on computed tomographic pulmonary angiography and elevated cardiac biomarkers. The primary end-point analysis tested for a difference between groups for the change in RV/LV ratio at 48 hours, assessed by a blinded independent imaging core laboratory. Secondary end points included major adverse events within 7 days (a composite of clinical deterioration necessitating rescue therapy, PE-related mortality, symptomatic recurrent PE, and major bleeding), adjudicated by an external clinical events committee. Additional outcomes included change in vital signs and core laboratory–assessed pulmonary artery obstruction at 48 hours. RESULTS: A total of 100 patients enrolled across 22 sites were randomized to CAVT (n=47) or anticoagulation alone (n=53). Baseline characteristics were comparable between arms. At 48 hours, mean reduction in RV/LV ratio was greater for CAVT (0.52±0.37) than anticoagulation (0.24±0.40), a difference of 0.27 (95% CI, 0.12–0.43; P <0.001). Refined modified and modified Miller scores exhibited greater changes for CAVT than anticoagulation alone at 48 hours ( P <0.001). Early normalization of vital signs within 48 hours was more frequent after CAVT. The major adverse event rate within 7 days was not different between groups (CAVT, 4.3% versus anticoagulation, 7.5%; P =0.681). Two PE-related deaths occurred in the CAVT arm. CONCLUSIONS: CAVT was superior to anticoagulation alone in reducing RV/LV ratio within 48 hours in patients with intermediate-high risk PE, accompanied by earlier normalization of vital signs and major adverse event rates comparable to those for anticoagulation. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05684796.
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Cite This Study
Lookstein et al. (2025) conducted an RCT in Acute intermediate-high risk pulmonary embolism (n=100). Computer-assisted vacuum thrombectomy (CAVT) with anticoagulation vs. Anticoagulation alone was evaluated on Change in RV/LV ratio at 48 hours (MD 0.27, 95% CI 0.12-0.43, p=<0.001). Computer-assisted vacuum thrombectomy with anticoagulation was superior to anticoagulation alone in reducing RV/LV ratio at 48 hours (difference 0.27; 95% CI 0.12-0.43; P<0.001).