1 Department of Cardiovascular, Respiratory, Nephrological, Anesthesiological and Geriatric Sciences, University of Rome, "La Sapienza", Policlinico Umberto Primo, Rome, Italy.
2 Department of Anesthesia and Intensive Care, IRCCS-ISMETT (Istituto Mediterraneo per i Trapianti e Terapie ad alta specializzazione), Palermo, Italy.
3 Department of Experimental and Clinical Medicine, Unit of Internal Medicine and Cardiology, University of Florence, Florence, Italy.