[1] Univ Thessaly, Dept Cardiothorac Surg, Larisa, Greece
[2] Soc Jr Doctors, Surg Working Grp, Athens, Greece
[3] Imperial Coll London, Dept Surg & Canc, St Marys Hosp, London W2 1NY, England
[4] Univ Thessaly, Fac Med, Sch Hlth Sci, Dept Vasc Surg, Larisa, Greece
[5] Oxford Univ Hosp, Dept Cardiothorac Surg, Oxford, England
[6] Univ Hosp Larissa, Dept Cardiothorac Surg, Biopolis, Larisa 41110, Greece