1. Department of Thoracic and Cardiovascular Surgery, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio
2. Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby, Denmark
3. Heart and vascular theme, Karolinska University Hospital, Stockholm, Sweden
4. Department of Surgery, Heart Center, Turku University Hospital, University of Turku, Turku, Finland
5. Department of Cardiothoracic Surgery, Heart Center, Tampere University Hospital, Tampere, Finland
6. Department of Clinical Sciences, Skane University Hospital, Lund University, Lund, Sweden
7. Department of Cardiothoracic Surgery, Skane University Hospital, Lund University, Lund, Sweden
8. Statistiska Konsultgruppen, Gothenburg, Sweden
9. Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
10. Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
11. Section of Cardiac Surgery, Yale University School of Medicine, New Haven, Connecticut
12. Department of Cardiothoracic Surgery, Landspitali University Hospital, Hringbraut, Reykjavik, Iceland