1. Division of Cardiology, Policlinico-Vittorio Emanuele Hospital, University of Catania, Italy (M.B., C.T.).
2. National Centre for Global Health–Istituto Superiore di Sanità, Rome, Italy (P.D., S.R., F.S.).
3. Department of Surgery, University of Oulu, Finland (F.B.).
4. Heart Center, Turku University Hospital, and Department of Surgery, University of Turku, Finland (F.B.).
5. Department of Cardiothoracic and Vascular Anesthesia and ICU–IRCCS Policlinico San Donato, San Donato Milanese (Milan), Italy (M.R.).
6. Fondazione G.Monasterio CNR/Regione Toscana per la Ricerca Medica e la Sanità Pubblica, Florence, Italy (G.S.).
7. Department of Epidemiology of Lazio Regional Health Service, Rome, Italy (D.F.).