Left atrial appendage CLOSURE in patients with Atrial Fibrillation at high risk of stroke and bleeding compared to medical therapy (CLOSURE-AF-DZHK16)

Atrial fibrillation is the most common cardiac arrhythmia. Fibrillation can cause blood clots to form: More than 90 percent of the blood clots occur in the left atrial appendage, a sac in the left atrium of the human heart. From there, the clots can find their way into the blood vessels of the brain and cause a stroke.

The DZHK study CLOSURE-AF compares the benefit of the left atrial appendage closure with the best possible drug therapy for high-risk patients with atrial fibrillation. In this group of patients, about 20 to 25 percent of the total population, drug treatment with anticoagulants is not possible because the risk of bleeding and stroke is too high.

As an alternative to taking anticoagulants, there is a new procedure: The left atrial appendage is closed with a kind of mini-screen so that no blood clots can enter the brain or the body from there. The closure is placed using a catheter. After the procedure, patients only have to take blood thinners until the occlusion has healed.

There is a lack of well-founded data on the benefits of this method for high-risk patients with a high risk of bleeding and a high risk of stroke. The CLOSURE AF study is the world's largest clinical study on the best possible therapy for high-risk patients with atrial fibrillation. More than 1,500 patients will be enrolled, with 17 DZHK centers and 45 other centers in Germany participating. The Competence Network Atrial Fibrillation is responsible for the regulatory project management of the study. The study is led by Professor Ulf Landmesser, Director of the Clinic for Cardiology at the Charité - Universitätsmedizin Berlin.

Starting in the first quarter of 2018, patients will be recruited for the study over a period of three years, the total duration of which is expected to be five years. The results of the CLOSURE AF study will be included in the guidelines for the treatment of patients with atrial fibrillation and a high risk of stroke and bleeding.

Publications

Left Atrial Appendage Closure or Medical Therapy in Atrial Fibrillation. Landmesser et al. N Engl J Med. 2026 Apr 2;394(13):1270-1280. doi:10.1056/NEJMoa2513310.

Catheter-based left atrial appendage CLOSURE in patients with atrial fibrillation at high risk of stroke and bleeding as compared to best medical therapy: Rationale and design of the prospective randomized CLOSURE-AF trial. Am Heart J. 2026 Feb:292:107273. doi: 0.1016/j.ahj.2025.09.005. Epub 2025 Sep 12.

More publications here

Principal Investigators

Principal investigator: Ulf Landmesser (Berlin), Co-PI: Ingo Eitel (Lübeck), Leif-Hendrik Boldt (Berlin)

Press releases and news

19.03.2026

Personalised treatment for atrial fibrillation (CLOSURE-AF-DZHK16 study)

 

12.12.2017

DZHK study on stroke prevention in high-risk patients

 

Study recruitment is available in these cities

The map only displays recruitment locations within Germany.