TOPLINE:

Among patients with acute intermediate-risk pulmonary embolism, ultrasound-facilitated catheter-directed fibrinolysis plus anticoagulation reduced the risk for the composite of pulmonary embolism-related death, cardiopulmonary decompensation or collapse, or symptomatic recurrence of pulmonary embolism within 7 days compared with anticoagulation alone.

METHODOLOGY:

• Researchers conducted a multinational randomized trial to assess whether ultrasound-facilitated catheter-directed fibrinolysis combined with anticoagulation vs anticoagulation alone improved clinical outcomes in patients with acute intermediate-risk pulmonary embolism.
• They included 544 patients (mean age, 58.2 years; 42.6% women) who had a ratio of right to left ventricular end-diastolic diameter of at least 1.0, elevated troponin levels, and at least two indicators of cardiorespiratory distress (systolic blood pressure of ≤ 110 mm Hg, heart rate of ≥ 100 beats/min, respiratory rate of > 20 breaths/min, or hypoxemia) within 6 hours of treatment allocation.
• Patients underwent ultrasound-facilitated catheter-directed fibrinolysis with alteplase plus anticoagulation (n = 273; intervention group) or anticoagulation alone (n = 271; control group).
• The primary outcome was a composite of pulmonary embolism-related death, cardiorespiratory decompensation or collapse, or nonfatal symptomatic recurrence of pulmonary embolism within 7 days.
• Additional outcomes included major bleeding, ischemic stroke, or intracranial hemorrhage within 7 and 30 days, and serious adverse events within 30 days.

TAKEAWAY:

• The intervention group had a 61% lower risk for the composite primary outcome than the control group (incidence of the primary outcome, 4.0% vs 10.3%; relative risk [RR], 0.39; P = .005).
• The incidence of cardiorespiratory decompensation or collapse events was lower in the intervention group than in the control group (3.7% vs 10.3%; RR, 0.40; 95% CI, 0.2-0.7), which drove the difference in the primary outcome.
• The incidence of major bleeding events did not differ meaningfully between groups at 7 or 30 days, and no intracranial hemorrhages occurred.
• The incidence of other serious adverse events through 30 days was also similar between groups.

IN PRACTICE:

“The finding that ultrasound-facilitated, catheter-directed thrombolysis plus anticoagulation was associated with a lower risk of acute clinical deterioration than anticoagulation alone in a multicenter, randomized, controlled trial of this scale represents a major advance in the foundation of evidence for thrombolytic approaches,” experts wrote in an editorial accompanying the journal article.

SOURCE:

This study was led by Kenneth Rosenfield, MD, Massachusetts General Hospital, Boston. It was published online on March 28, 2026, in The New England Journal of Medicine.

LIMITATIONS:

The trial was not blinded. Because the events occurred at a low frequency, the study lacked the statistical power to compare efficacy in prespecified subgroups and to draw firm conclusions about between-group differences in bleeding complications. Randomization was not stratified by site; therefore, potential center-level effects could not be ruled out.

DISCLOSURES:

The trial was funded by Boston Scientific. Three authors reported being employees of Boston Scientific. Several authors disclosed relationships including receiving research grants, speaker honoraria, travel support, payments for talks and workshops, and lecture fees; holding stocks or stock options; being members of scientific advisory boards; and having consultancy roles and employment and other ties with various medical device and pharmaceutical companies, including Boston Scientific.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.