Ultrasound-Facilitated, Catheter-Directed Fibrinolysis for Acute Pulmonary Embolism

BACKGROUND: Whether anticoagulation alone is an adequate treatment for acute, intermediate-risk pulmonary embolism is uncertain. METHODS: We conducted a multinational, adaptive-design trial with blinded outcome adjudication. Patients with intermediate-risk pulmonary embolism (with a ratio of right ventricular end-diastolic diameter to left ventricular end-diastolic diameter of ≥1.0 and an elevated troponin level) were eligible if they had at least two indicators of cardiorespiratory distress (systolic blood pressure of ≤110 mm Hg, a heart rate of ≥100 beats per minute, or a respiratory rate of >20 breaths per minute). Patients were randomly assigned to undergo ultrasound-facilitated, catheter-directed fibrinolysis with alteplase plus anticoagulation (the intervention group) or anticoagulation alone (the control group) according to prespecified treatment protocols. The primary outcome was a composite of pulmonary embolism-related death, cardiorespiratory decompensation or collapse, or symptomatic recurrence of pulmonary embolism within 7 days. RESULTS: The intention-to-treat population comprised 544 patients: 273 in the intervention group and 271 in the control group. The mean (±SD) age was 58.2±13.5 years, and 42.6% of the patients were women. A primary-outcome event occurred in 11 patients (4.0%; 95% confidence interval [CI], 2.3 to 7.1) in the intervention group and 28 (10.3%; 95% CI, 7.2 to 14.5) in the control group (relative risk, 0.39; 95% CI, 0.20 to 0.77; P = 0.005). The effect was driven primarily by a lower risk of cardiorespiratory decompensation or collapse in the intervention group. Major bleeding occurred within 7 days after randomization in 11 patients (4.1%) in the intervention group and 6 (2.2%) in the control group (P = 0.32); major bleeding occurred within 30 days in 11 patients (4.1%) and 8 patients (3.0%), respectively (P = 0.64). No substantial between-group differences in the incidence of other serious adverse events were observed up to 30 days after randomization; no intracranial hemorrhage occurred. CONCLUSIONS: In patients with acute, intermediate-risk pulmonary embolism, ultrasound-facilitated, catheter-directed fibrinolysis plus anticoagulation led to a lower risk of the composite of pulmonary embolism-related death, cardiopulmonary decompensation or collapse, or symptomatic recurrence of pulmonary embolism within 7 days than anticoagulation alone. (Funded by Boston Scientific; HI-PEITHO ClinicalTrials.gov number, NCT04790370.).