Davide Pacini1, Giacomo Murana2, Luca Di Marco2. 1. Cardiac Surgery Unit, Cardio-Thoraco-Vascular Department, S. Orsola Hospital, University of Bologna, Bologna, Italy. Electronic address: davide.pacini@unibo.it. 2. Cardiac Surgery Unit, Cardio-Thoraco-Vascular Department, S. Orsola Hospital, University of Bologna, Bologna, Italy.