For older people with irregular heart rhythms who are at high risk of stroke and bleeding, standard care—including the timely use of anticoagulant blood thinners, when indicated—has been found to be the better choice compared to a catheter-based procedure, according to preliminary late-breaking science presented at this year’s American Heart Association (AHA) Scientific Sessions (7–10 November 2025, New Orleans, USA).
While blood thinners can be highly effective in reducing the risk of stroke among people with atrial fibrillation (AF), the medication may cause severe bleeding in some people. Due to this risk, researchers are exploring alternative treatments, including the catheter-based left atrial appendage (LAA) closure procedure, which seals a small pouch in the heart where blood clots can form, thus reducing stroke risks as well as potentially removing the need for patients to take blood thinners for clot prevention.
The CLOSURE-AF study compared catheter-based LAA closure with physician-directed standard medical care in more than 900 adult AF patients at high risk for stroke and bleeding. Patients were enrolled at 42 healthcare sites in Germany from March 2018 to April 2024, and were followed for a median of three years after randomisation to receive either standard medical care or LAA closure. The aim of the study was to demonstrate non-inferiority for catheter-based LAA closure regarding the risk of stroke, systemic embolism, cardiovascular/unexplained death, or major bleeding; however, this goal was not reached.
“We expected that catheter-based LAA closure would be comparable to physician-directed standard medical care, often using blood-thinning anticoagulant medications,” said study lead researcher Ulf Landmesser (Charité University Medicine, Berlin, Germany). “However, this was not the case in this trial of older patients at very high risk of bleeding and stroke. Our findings indicate that standard, physician-directed medical care, including blood thinners for eligible patients, remains a valid management option for those older patients with irregular heartbeat who are at very high risk for stroke and bleeding.”
Landmesser added that the results of the procedure are different for lower-risk patients, and studies investigating this are currently underway. Moreover, ongoing studies are comparing LAA closure in addition to blood thinning in very high-risk patients.
The CLOSURE-AF researchers also believe that, because medical treatments and LAA closure for AF remain in development, the results of this study may not apply to future research, nor other techniques or procedures.
