[1] Univ Florence, Dept Expt & Clin Med, Cardiac Surg Unit, Florence, Italy
[2] Univ Toronto, St Michaels Hosp, Div Cardiac Surg, Toronto, ON, Canada
[3] Maastricht Univ, Cardiovasc Res Inst Maastricht CARIM, Med Ctr, Maastricht, Netherlands
[4] Univ Siena, Dept Med Biotech nol, Cardiac Surg, Siena, Italy
[5] Univ Hosp Ctr Tirana, Div Cardiac Surg, Tirana, Albania
[6] Univ Florence, Careggi Teaching Hosp, Dept Expt & Clin Med, Cardiac Surg Unit, Largo Brambilla 3, I-50134 Florence, Italy