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The researchers also found that the anticoagulant drugs, called Apixaban and Vitamin K antagonists (VKAs), also may have a positive impact on a patient’s cognitive function

A trial led by the University of Birmingham has found that two types of blood thinning drugs are safe to use in patients with an irregular heartbeat when they are undergoing surgery aimed at stopping the condition.

The anticoagulant drugs, called Apixaban and Vitamin K antagonists (VKAs), also may have a positive impact on a patient’s cognitive function, found the research published today in European Heart Journal.

Atrial fibrillation – a condition that causes an irregular heartbeat - affects people of all ages and doubles the risk of premature death through heart failure and triggers one in three strokes.

Specialist teams can cure atrial fibrillation by stopping the irregular electrical signals in the heart that cause the symptoms via a procedure known as catheter ablation. In this procedure, an electrophysiologist uses a long wire, threaded into the heart via the groin, to deliver a high-frequency electric current. This heats the inner surface of the heart where the irregular electrical signals occur, creating scar tissue and so preventing the faulty impulses.

Patients with atrial fibrillation are at their greatest risk of stroke in the hours and days following this procedure. Therefore, they require anticoagulants to thin the blood and prevent blood clots.

To determine the optimal anticoagulation therapy for patients undergoing catheter ablation, the German Atrial Fibrillation NETwork (AFNET), in cooperation with the German Centre for Cardiovascular Research, (DZHK) carried out the AXAFA – AFNET 5 trial comparing Apixban and VKAs. In the randomised trial, 633 patients in Europe and the USA received either continuous Apixaban or a VKA before and post their catheter ablation.

Professor Paulus Kirchhof, of the University of Birmingham’s Institute of Cardiovascular Sciences, International Chief Investigator of the clinical trial and Chairman of AFNET, said: “Catheter ablation is being used increasingly to treat patients with symptomatic atrial fibrillation, but the procedure leaves patients at a certain risk of stroke, bleeding, and clinically silent acute brain lesions. We also know that thrombotic events can impair cognitive function.

“We found the bleeding rate was half of what we have expected and there was a remarkably low rate of stroke, with only two events being observed in the trial.

“In addition, seven episodes of cardiac tamponade – two with Apixaban and five with a VKA – were managed with drainage, without the need for antidotes.”

Using the Montreal Cognitive Assessment test, the investigators found a small but statistically significant improvement in cognitive function in both study groups at the end of the study.

Another unique feature of the trial was the use of brain magnetic resonance imaging (MRI) in more than half of the study patients within 48 hours after ablation to quantify procedure-related acute ischaemic brain lesions. The results of the brain MRI substudy demonstrated no difference in clinically silent acute brain lesions between the treatment arms.

Professor Kirchhof said that the results of the trial will have a big impact on treatment: “The results of this trial will go a long way towards reassuring clinicians that continuous Apixaban is a safe and effective alternative to VKA for patients undergoing atrial fibrillation ablation, even those at risk of stroke.”

Professor Kirchhof is presenting an abstract of these findings today at the European Society of Cardiology’s Congress in Barcelona, Spain.

For more information please contact Emma McKinney, Communications Manager (Health Sciences), University of Birmingham, call +44 (0)121 414 6681. Alternatively, contact the Press Office out of hours on +44 (0)7789 921165.

  • The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 5,000 international students from over 150 countries.
  • Kirchhof et al (2018). ‘Apixaban in patients at risk of stroke undergoing atrial fibrillation ablation’. European Heart Journal. DOI:
  • Read the full paper
  • The German Atrial Fibrillation NETwork (AFNET) initiated and conducted the AXAFA – AFNET 5 trial. The study was partially funded by the German Centre for Cardiovascular Research (DZHK). Financial support was provided by Bristol-Myers Squibb and Pfizer. 
  • The Atrial Fibrillation NETwork (AFNET) is an interdisciplinary research network comprising scientists and physicians from hospitals and practices dedicated to improving the management of atrial fibrillation through coordinated research in Germany, Europe, and the USA. Its main objective is to conduct high quality investigator-initiated clinical trials and registries on a national and international level. The AFNET continues the long-term activities of the network which has been funded by the German Federal Ministry of Research and Education over a decade. Since January 2015, specific projects and infrastructures of the AFNET are funded by the German Centre for Cardiovascular Research (DZHK). 
  • The research was carried out in collaboration with the following:
  1. University of Birmingham Institute of Cardiovascular Sciences
  2. SWBH NHS Trust, Birmingham, UK
  3. University Hospitals Birmingham, Birmingham, UK
  4. Atrial Fibrillation NETwork association (AFNET), Münster, Germany
  5. Center for Stroke Research Berlin & Department of Neurology, Charité – Universitätsmedizin
  6. Berlin, Germany
  7. Hospital of the University of Pennsylvania, Philadelphia, USA
  8. Isala Heart Center Zwolle, Zwolle, The Netherlands
  9. The Clinical Research Institute, Munich, Germany
  10. University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
  11. Sentara Cardiovascular Research Institute, Norfolk, Virginia, USA
  12. Ospedale Generale Regionale F. Miulli, Acquaviva delle Fonti, Italy
  13. Gentofte Hospital, Hellerup, Denmark
  14. Abteilung für Rhythmologie, Leipzig Heart Center, Leipzig, Germany.
  15. Department of Biostatistics & Bioinformatics, Duke University School of Medicine, USA
  16. Duke Clinical Research Institute (DCRI), Durham, NC, USA
  17. Hospital Clinic Barcelona, University of Barcelona, Barcelona, Spain
  18. Department of Cardiology, Aarhus University Hospital, Denmark
  19. Herz- und Diabeteszentrum NRW, Ruhr-Universität Bochum, Bad Oeynhausen, Germany
  20. Duke University, Division of Cardiology Duke University Medical Center, Durham NC, USA
  21. Cardiovascular Center, OLV Aalst, Belgium
  22. Department of Cardiology, Medical University Graz, Austria
  23. University Maastricht, Department of Physiology, Maastricht, Netherlands
  24. Ospedale Dell'Angelo, Mestre, Italy
  25. Liverpool Heart and Chest Hospital, Liverpool, UK
  26. Jessa Ziekenhuis, Campus Virga Jesse, Hasselt, Belgium
  27. Albert Einstein College of Medicine, at Montefiore Hospital, New York, USA
  28. Texas Cardiac Arrhythmia Institute at St. David’s Medical Center, Austin, Texas, USA