1. Department of Surgery, University of Oulu, Oulu, Finland
2. Department of Surgery, University of Turku, Turku, Finland
3. Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
4. National Centre for Global Health, Istituto Superiore di Sanità, Rome, Italy
5. Division of Cardiology, Policlinico Vittorio Emanuele Hospital, University of Catania, Italy
6. Italian National Agency for Regional Healthcare Services, Rome, Italy