Is There a Golden Hour for Thrombectomy in Intermediate-Risk Pulmonary Embolism? Insights From SYMPHONY-PE

BACKGROUND: Recent observational studies have suggested that early treatment (<12 hours from diagnosis) of intermediate risk pulmonary embolism (PE) with catheter-based therapies may reduce morbidity and mortality. However, the effect of early versus late mechanical thrombectomy on acute pulmonary hemodynamics and right ventricular mechanics is less well defined. METHODS: Patients enrolled in SYMPHONY-PE were divided into one of 2 groups based on the time from baseline CT pulmonary angiography to mechanical thrombectomy: Early <12 hours versus late ≥12 hours. The primary safety end point was the rate of major adverse events within 48 hours, as adjudicated by an academic independent safety board. The primary efficacy end point was the core-lab assessed mean change in right ventricle–to–left ventricle ratio from baseline to 48 hours. RESULTS: Early thrombectomy was performed in 44% (48/109) of patients and was associated with a larger reduction, approaching statistical significance, in right ventricle–to–left ventricle ratio (0.52±0.50 versus 0.37±0.34; P =0.071). Mean pulmonary artery pressure decreased significantly more in patients receiving early thrombectomy (8.6±5.2 versus 5.8±5.0 mm Hg; P =0.006). The major adverse events rate was similar ( P =0.431) between groups, and there were no mortalities. The differences in efficacy outcomes were greatest in higher-risk patients per the Composite Pulmonary Embolism Shock score. CONCLUSIONS: Early mechanical thrombectomy was associated with larger reductions in right ventricle–to–left ventricle ratio and mean pulmonary artery pressure, with no significant differences in safety event rates compared with patients who underwent late thrombectomy. Randomized trials are needed to test these associations. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT06062329.