Catheter-directed, ultrasound-facilitated fibrinolysis in obese patients with massive and submassive pulmonary embolism

Obesity is a well-established risk factor for pulmonary embolism (PE). However, treatment of PE in obese patients is challenging because of limited outcomes data, especially with advanced therapies such as catheter-based fibrinolysis. We assessed the efficacy and safety of ultrasound-facilitated, catheter-directed fibrinolysis in obese patients with submassive and massive PE enrolled in the SEATTLE II Trial. Eligible patients had a right ventricular-to-left ventricular (RV/LV) diameter ratio ≥ 0.9 on chest computed tomography (CT). The primary efficacy outcome was the change in chest CT-measured RV/LV diameter ratio at 48 h after procedure initiation. The primary safety outcome was GUSTO major bleeding within 72 h. One-hundred and four patients were obese, as defined by a BMI ≥ 30 kg/m², and 44 were non-obese. Mean RV/LV ratio was greater in obese patients at baseline compared with non-obese patients (1.60 vs. 1.43, p = 0.02). Reduction in RV/LV diameter ratio at 48 h was greater in obese patients compared with non-obese patients (absolute reduction: − 0.47 vs. − 0.30, p = 0.01; relative reduction: − 26 vs. − 18%, p = 0.03). Major bleeding occurred in 12 (12%) of obese patients and in 3 (7%) in non-obese patients (p = 0.55). In conclusion, ultrasound-facilitated, catheter-directed fibrinolysis shows promise in obese patients for whom advanced therapy for acute PE is warranted.