1. Department of Medical Biotechnologies, Division of Cardiology, University of Siena , Viale Mario Bracci, 1, 53100 Siena , Italy
2. Division of Cardiology, Department of Cardiovascular Diseases—AUSL Romagna, ‘Santa Maria delle Croci’ Hospital , Ravenna , Italy
3. Cardiac Surgery, St. Michael Hospital , Toronto, ON , Canada
4. Department of Cardiac Surgery, Azienda Ospedaliera Universitaria Senese , Siena , Italy
5. Institute of Public Health and Clinical Medicine, Umea University , Umea , Sweden