1. First Department of Surgery, Vascular Unit, Laiko General Hospital, National & Kapodistrian University of Athens, 11527 Athens, Greece
2. Vascular Unit, General University Hospital of Thessaly, 41110 Larisa, Greece
3. Department of General Surgery, Royal Free Hospital, NW3 2QG London, UK
4. Vascular Unit, Royal Free Hospital, NW3 2QG London, UK