[1] Univ Iceland, Fac Med, Landspitali Univ Hosp, Dept Cardiothorac Surg, Reykjavik, Iceland
[2] Karolinska Univ Hosp, Dept Cardiothorac Surg, Stockholm, Sweden
[3] Yale Sch Med, Div Cardiac Surg, New Haven, CT USA
[4] Univ Turku, Turku Univ Hosp, Dept Cardiothorac Surg, Turku, Finland
[5] Aarhus Univ Hosp, Dept Cardiothorac Surg, Aarhus, Denmark
[6] Gothenburg Univ, Sahlgrenska Acad, Inst Med, Dept Mol & Clin Med, Gothenburg, Sweden
[7] Sahlgrens Univ Hosp, Dept Cardiothorac Surg, Gothenburg, Sweden
[8] Tampere Univ, Heart Hosp, Tampere, Finland
[9] Tampere Univ, Tampere, Finland
[10] Lund Univ, Skane Univ Hosp, Dept Clin Sci, Dept Cardiothorac Surg, Lund, Sweden