SYMPHONY-PE: Early Thrombectomy Improves Pulmonary Embolism Outcomes

New data from the recent SYMPHONY-PE trial have indicated that early mechanical thrombectomy results in greater cardiovascular improvements without significant differences in safety event rates compared to late thrombectomy for pulmonary embolism (PE).1

The study, led by Sripal Bangalore, MD, professor of medicine at NYU Langone Health, is the third in a series of investigations looking at the benefits of early versus late intervention in patients with PE. The present trial largely demonstrates similar endpoint data, reinforcing the hypothesis that early thrombectomy improves various aspects of patients’ well-being following their surgery.1

“I would say that, given that my team has published a number of these analyses looking at timelines, we have shown that early consistently appears to be better,” Bangalore told HCPLive in an exclusive interview. “We have 2 other analyses already published, where we show that early is potentially beneficial at reducing the risk of adverse clinical endpoints.”

SYMPHONY-PE Study Structure

SYMPHONY-PE was a prospective, multicenter, single-arm interventional study to determine the efficacy and safety of the Symphony Thrombectomy System from Imperative Care in patients with acute, intermediate-risk PE. Patients were eligible for inclusion if they had evidence of acute PE within ≤14 days, systolic blood pressure (BP) ≥90 mmHg with evidence of dilated right ventricle and a right ventricle/left ventricle (RV/LV) ratio >0.9, and a stable heart rate <130 BPM prior to the operation, among other criteria. Patients who had used thrombolytics within 14 days of baseline CTA, platelets <100,000/µL, and kidney dysfunction, among other criteria, were excluded.1,2

The study’s primary endpoints were the rate of major adverse events over 48 hours postoperatively, including major bleeding, device-related mortality, and device-related serious adverse events, and mean reduction of RV/LV ratio from baseline to 48 hours. Secondary endpoints included rates of PE-related mortality, all-cause mortality, symptomatic PE recurrence, and device related serious adverse events at 30 days postoperatively.2

A total of 109 patients were treated with the Symphony Thrombectomy System – of these, 48 received early thrombectomy. The majority of early treatments were completed within 6 hours, with the median time from CTPA to obtaining access sitting at 4.9 hours in the early treatment group and 25.3 hours in the late treatment group.1

Outcomes of Early Treatment

Baseline mean pulmonary artery pressure (PAP) was similar between groups but decreased substantially more after early thrombectomy (28 +/- 15% versus 18 +/- 24% reduction; P = .01). Baseline clot burden, measured with the refined Modified Miller Index, was substantially higher in the patients treated earlier (25.5 +/- 3.5 versus 23.5 +/- 4.3; P = .011). Baseline RV/LV and reduction in RV/LV at 48 hours were also both higher in the early treatment group, with difference in 48 hours RV/LV approaching statistical significance.1

Bangalore and colleagues then conducted an additional treatment time subgroup analysis, including patients with the highest CPES scores of 5 or 6. Similar trends for the efficacy endpoints were observed for this population, with higher risk patients who received earlier treatment displaying a substantially larger RV/LV reduction between baseline and 48 hours than those who were treated late.1

Ultimately, Bangalore and colleagues determined that early intervention in PE is associated with significantly better outcomes for patients. However, the study and the 2 contemporaries published by the team were observational, and Bangalore makes clear that these trials are primarily hypothesis-generating as opposed to evidence-collecting.1

“I absolutely think we need more studies. This is, at least, hypothesis-generating, trying to ask a question,” Bangalore said. “Going beyond the phase of ‘do patients need mechanical thrombectomy’, we’re trying to ask ‘if patients need mechanical thrombectomy, when should we do it? Should it be earlier in the course versus late?’ And at least based on all of the observational studies published so far, there seems to be a benefit of going early.”

Editors’ Note: Bangalore reports disclosures with Angiodynamics, Stryker, Jupiter, Recor, Abbott Vascular, and others.

References

1. Bangalore S, Tomalty RD, Kado H, et al. Is there a golden hour for thrombectomy in intermediate-risk pulmonary embolism? insights from symphony-PE. Circulation: Cardiovascular Interventions. Published online June 18, 2026. doi:10.1161/circinterventions.126.016573

2. Imperative Care, Inc. SYMPHONY-PE Study for Treatment of Pulmonary Embolism. ClinicalTrials.gov Identifier: NCT06062329. Updated July 15, 2025. Accessed July 14, 2026. https://clinicaltrials.gov/study/NCT06062329