1. Cardiac Surgery Division, Tor Vergata University Hospital, 00133 Rome, Italy
2. Unit of Cardiology of the Cardiac Surgery Division, Tor Vergata University Hospital, 00133 Rome, Italy
3. Unit of Vascular Surgery, Tor Vergata University Hospital, 00133 Rome, Italy
4. Unit of Cardio-Thoracic Anesthesia, Tor Vergata University Hospital, 00133 Rome, Italy