Low-dose, short-duration catheter-directed thrombolysis for acute intermediate-high-risk pulmonary embolism: the...

Catheter-directed thrombolysis (CDT) reduces the right-to-left ventricular ratio (RV/LV ratio) in patients with intermediate-risk pulmonary embolism (PE). Prior randomised studies comparing CDT to anticoagulation used ultrasound-assisted devices and high doses of thrombolytics with extended infusion durations, which may increase healthcare costs and complications, thereby limiting its clinical applicability.

We sought to evaluate the efficacy and safety of low-dose, short-duration CDT compared with unfractionated heparin (UFH) in patients with acute intermediate-high-risk PE.

In this open-label, randomised controlled trial, patients with acute intermediate-high-risk PE were randomised 1:1 to receive CDT (4 mg recombinant tissue plasminogen activator [r-tPA] per catheter over 2 hours) plus UFH or UFH alone. The primary endpoint was the change in RV/LV ratio at 24 hours. Secondary endpoints included thrombus burden reduction, changes in vital signs and echocardiographic measures of RV function, length of hospital stay, 30-day mortality, and 90-day recurrent PE. Safety endpoints included major and minor bleeding.

Between August 2020 and October 2024, 60 patients were randomised, with 58 completing follow-up (CDT: n=29; UFH: n=29). CDT plus UFH improved the RV/LV ratio at 24 hours compared with UFH alone (-0.17 vs +0.02; p=0.01). Secondary endpoints did not differ between groups. One death occurred in the UFH group. One patient experienced haemodynamic deterioration during CDT, successfully managed with additional r-tPA. No major bleeding occurred. Minor bleeding occurred in three patients (10%) in the CDT group and one (3%) in the UFH group (p=0.29).

Low-dose, short-duration CDT plus UFH improved the RV/LV ratio without increasing major bleeding compared with UFH alone in intermediate-high-risk PE.