1. Department of Cardiology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, Austria
2. Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Spitalgasse 23, Vienna, Austria
3. Department of Cardiac Surgery, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, Austria
4. Department of Cardiac Surgery, Medical University of Innsbruck, Anichstraße 35, Innsbruck, Austria