Optimal Duration of Ultrasound-Facilitated Catheter-Directed Thrombolysis for Acute Pulmonary Embolism: A Retrospective Cohort Study

Background/Objectives: The mortality rate for acute high-risk and intermediate–high-risk pulmonary embolism (PE) was high despite treatment with heparin anticoagulation alone. Although adjunctive systemic thrombolysis can significantly reduce mortality, it still increases the incidence of major bleeding. Ultrasound-facilitated catheter-directed thrombolysis (USCDT) has been shown to reduce the incidence of major bleeding; however, the optimal treatment duration remains uncertain. Methods: This retrospective cohort study included 155 hospitalized patients with acute PE who underwent USCDT between January 2017 and June 2025 in the intensive care unit at China Medical University Hospital, Taichung, Taiwan. Patients were categorized into four groups based on average usage time: <20, 20–29, 30–39, and ≥40 h. The primary endpoints were 30-day all-cause mortality rate and major bleeding. Covariates associated with 30-day all-cause mortality were estimated and adjusted using logistic regression modeling. Results: Across all treatment groups, USCDT significantly reduced systolic pulmonary artery (PA) pressure (26.9%), mean PA pressure (21.0%), fibrinogen levels (25.2%), and right ventricle-to-left ventricle diameter ratio (21.5%) (all p < 0.001). Compared with the group with a USCDT ≥ 40 h, the group with a USCDT < 20 h had a lower odds ratio for 30-day all-cause mortality (OR: 0.36, 95% CI: 0.07–1.81). A similar benefit was observed for a USCDT 20–29 h. Conclusions: USCDT < 20 or 20–29 h (mean 15–20 mg alteplase) may provide an optimal balance between efficacy and safety by reducing 30-day all-cause mortality and major bleeding in patients with acute PE.