[1] Univ Siena, Dept Cardiovasc Dis, I-53100 Siena, Italy
[2] Univ Siena, Dept Cardiac Surg, I-53100 Siena, Italy
[3] Univ Siena, Unit Anesthesia, I-53100 Siena, Italy
[4] Univ Siena, Dept Surg & Bioengn, Intens Care Unit, I-53100 Siena, Italy
[5] Federico II Univ Hosp, Dept Clin & Expt Med, Cardioangiol Unit CCU, Naples, Italy