1. Department of Cardiac Surgery, Medical University of Vienna , Vienna, Austria
2. Center for Medical Statistics, Informatics, and Intelligent Systems (CeMSIIS), Medical University of Vienna , Vienna, Austria
3. EUROMACS Registry, EACTS House , Windsor, UK
4. Department of Cardiology, Leiden University Medical Center , Leiden, Netherlands
5. Department of Cardiothoracic Surgery, Oslo University Hospital , Rikshospitalet, Norway
6. Department of Cardiac Surgery, University of Navarra , Pamplona, Spain