[1] Univ Helsinki, Helsinki Univ Hosp, Heart & Lung Ctr, Dept Cardiac Surg, Helsinki 00029, Finland
[2] Univ Helsinki, South Karelia Cent Hosp, Dept Med, Lappeenranta 53130, Finland
[3] Ziekenhuis Oost Limburg, Dept Cardiac Surg, B-3600 Genk, Belgium
[4] Glenfield Hosp, Dept Cardiac Surg, Leicester LE3 9QP, Leics, England
[5] Ctr Cardiol Nord St Denis, Dept Cardiac Surg, F-93200 Paris, France
[6] Ludwig Maximilians Univ Munchen, LMU Univ Hosp, Dept Cardiac Surg, D-80539 Munich, Germany
[7] German Ctr Cardiovasc Res, Partner Site Munich Heart Alliance, D-80539 Munich, Germany
[8] Hop Univ Henri Mondor, AP HP, Dept Cardiac Surg, F-94000 Creteil, France
[9] Hop Univ Henri Mondor, AP HP, Dept Vasc Surg, F-94000 Creteil, France
[10] Univ Hosp Muenster, Dept Cardiothorac Surg, D-48149 Munster, Germany
[11] Univ Franche Comte, Dept Thorac & Cardiovasc Surg, F-25030 Besancon, France
[12] Univ Heart & Vasc Ctr Hamburg, Dept Cardiovasc Surg, D-20251 Hamburg, Germany
[13] Charles Univ Prague, Fac Med 3, Dept Cardiac Surg, Prague 10000, Czech Republic
[14] Univ Hosp Kralovske Vinohrady, Prague 10000, Czech Republic
[15] Univ Verona, Med Sch, Div Cardiac Surg, I-37124 Verona, Italy
[16] Univ Hosp Udine, Cardiothorac Dept, I-33100 Udine, Italy
[17] Univ Turin, Molinette Hosp, Cardiac Surg, I-10126 Turin, Italy
[18] Univ Barcelona, Hosp Clin Barcelona, Dept Cardiovasc Surg, Barcelona 08036, Spain
[19] Univ Hosp Gregorio Maranon, Cardiovasc Surg Dept, Madrid 28007, Spain
[20] Liverpool Heart & Chest Hosp, Liverpool Ctr Cardiovasc Sci, Liverpool L14 3PE, Merseyside, England
[21] Ctr Hosp Annecy Genevois, F-74370 Annecy, France
[22] Azienda Sanitaria Univ Giuliano Isontina, Cardiothorac & Vasc Dept, Div Cardiac Surg, I-34148 Trieste, Italy
[23] Univ Oulu, Res Unit Surg Anesthesia & Crit Care, Oulu 90570, Finland