Ultrasound-accelerated thrombolysis shows advantage over anticoagulation alone in submassive pulmonary embolism

Nils Kucher

Results of the ULTIMA pulmonary embolism trial comparing endovascular therapy to standard of care were presented at the American College of Cardiology meeting in San Francisco, USA, by Nils Kucher, University Hospital, Bern, Switzerland. 

ULTIMA is the world’s first randomised controlled trial comparing the use of an endovascular approach (EkoSonic ultrasound-accelerated thrombolysis, EKOS) along with anticoagulation to treat submassive pulmonary embolism vs anticoagulation therapy alone, the current standard of care. 


Kucher, principal investigator, reported on the 59-patient study conducted at eight European centres. Of the 59 patients, 30 were randomly selected and treated with EKOS catheters, a unique device that generates ultrasound energy while simultaneously delivering a clot-dissolving drug.

According to the company, the advantage of this combination is that the ultrasound conditions the clot resulting in more effective drug delivery; thus ensuring faster and more complete clot dissolution. All 59-patients’ heart function were measured pre- and 24 hours post- therapy. Patients in the EKOS group demonstrated statistically significant reduction in right heart enlargement with no adverse effects from the catheterisation. There were no serious bleeding events in either group. There was one death in the non-EKOS group for reasons other than pulmonary embolism.

Kucher commented, “ULTIMA is a pivotal study showing efficacy and safety of treating intermediate risk pulmonary embolism with a standardised interventional approach.” The average 24-hour improvement in right heart dysfunction among the EKOS treated patients, as measured using RV/LV ratio, was 23%, compared to anticoagulation treated patients whose average improvement was only 3%. This difference is both clinically and statistically significant (p<0.0001). While patients treated with anticoagulation alone will generally improve over time, the EKOS-treated patients continued to show a statistically significant (p<0.0001) greater reduction in right heart dysfunction at 90 days than patients treated with just anticoagulation.

Kucher added, “It is not unlikely that the ULTIMA study may be the beginning of a treatment paradigm shift for pulmonary embolism similar to what was seen two decades ago for acute coronary syndrome. We used to treat acute myocardial infarction with intravenous clot dissolving drugs; yet, today this drug therapy has almost exclusively been replaced by endovascular treatment with balloons and stents.” Kucher added,“ULTIMA promises to start a similar revolution for the treatment of pulmonary embolism patients at increased risk of death, changing management from IV drug therapy to an endovascular approach which may be safer.”

Samuel Z Goldhaber, professor of Medicine, Harvard Medical School and Director, Venous Thromboembolism Research Group, Brigham and Woman’s Hospital, Boston, USA, and principal investigator for the SEATTLE II study (150 patient single arm prospective trial studying EKOS treated patients suffering from massive and submassive pulmonary embolism) added: “The results of the ULTIMA trial clearly demonstrate that physicians now have another tool in their armamentarium for the safe and effective treatment of submassive pulmonary embolism.”