[1] Univ Patras, Sch Med, Dept Cardiothorac Surg, GR-26110 Patras, Greece
[2] Univ Ioannina, Sch Med, Dept Cardiac Surg, GR-45110 Ioannina, Greece
[3] Basildon & Thurrock Univ Hosp NHS FT, Basildon, Essex, England
[4] Univ Ioannina, Sch Med, Dept Clin Anesthesiol, GR-45110 Ioannina, Greece
[5] Univ Ioannina, Sch Med, Intens Postoperat Care Unit, GR-45110 Ioannina, Greece