[1] European Hosp, Dept Cardiac Surg, I-00149 Rome, Italy
[2] Univ Zurich Hosp, Dept Cardiac Surg, CH-8091 Zurich, Switzerland
[3] Hosp Univ Penn, Dept Cardiac Surg, Philadelphia, PA 19104 USA
[4] Ctr Heart, Dept Cardiac Surg, Leipzig, Germany
[5] Univ Hosp Bern, Dept Cardiac Surg, CH-3010 Bern, Switzerland
[6] Med Univ, Dept Cardiac Surg, Innsbuck, Austria
[7] Castle Hill Hosp, Dept Cardiac Surg, Kingston Upon Hull, N Humberside, England
[8] Policlin St Orsola, Dept Cardiac Surg, Bologna, Italy
[9] Skane Univ Hosp, Dept Cardiac Surg, Malmo, Sweden
[10] Herz & Gefaess Klin, Dept Cardiac Surg, Bad Neustadt an der Saale, Germany
[11] Acad Hosp Hubertus, Dept Vasc Surg, Berlin, Germany