Czech trial finds catheter therapy cuts 7-day composite endpoint

In a catheterization laboratory in Czechia, the question was whether a thin tube could change the first seven days after a dangerous lung clot. The PRAGUE-26 trial, led by Viktor Kočka and Dr. Josef Kroupa from Charles University and University Hospital Kralovske Vinohrady in Prague, randomized 558 patients at 11 sites to catheter-directed thrombolysis or anticoagulation alone.

Pulmonary embolism occurs when a clot blocks blood vessels in the lungs, reducing blood flow and increasing strain on the heart. Catheter-directed thrombolysis delivers thrombolytic medicine directly to the clot in the pulmonary artery. In this study, the researchers tested conventional CDT — without ultrasound facilitation — against standard treatment with intravenous unfractionated heparin or subcutaneous low-molecular-weight heparin.

The difference appeared in the trial’s main seven-day measure, which combined death from any cause, recurrent pulmonary embolism, and cardiorespiratory decompensation or collapse. That endpoint occurred in 0.7% of patients receiving CDT, compared with 6.8% receiving anticoagulation alone, a relative risk of 0.10. The reduction was driven mainly by fewer cases of cardiorespiratory decompensation or collapse, alongside early improvement in right-ventricular strain on echocardiography.

The safety picture was less dramatic. Bleeding occurred in 4.6% of the CDT group and 5.0% of the standard-care group within seven days, with no apparent difference reported by the investigators. But there were two intracranial bleeds in the catheter group and none in standard care. The study also recorded four deaths in standard care within seven days and one death in the CDT group within 30 days.

So what changes in practice? For patients with intermediate-high-risk pulmonary embolism, catheter treatment could offer tertiary-care centers an intervention alongside anticoagulation, particularly when early heart strain and collapse are the concern. The results show that the approach can be delivered across a national network of specialized centers, but they come from one randomized study; future European Society of Cardiology guidelines, due next year, will help determine how broadly the findings shape care.