1. Cardiac Surgery Unit, Department of Cardiac, Thoracic and Vascular Sciences University Hospital of Padua Padua Italy
2. Department of Surgery, Division of Cardiac Surgery Yale School of Medicine New Haven Connecticut USA
3. Department of Cardiothoracic Surgery, Lankenau Heart Institute, Lankenau Medical Center Main Line Health Wynnewood Pennsylvania USA
4. International School of Cardiac Surgery Ettore Majorana Foundation and Centre for Scientific Culture Erice Italy