1. Department of Thoracic and Vascular Surgery, North Karelia Central Hospital, Joensuu, Finland
2. Department of Thoracic and Vascular Surgery, South Karelia Central Hospital, Lappeenranta, Finland
3. Department of Thoracic and Vascular Surgery, South Savo Central Hospital, Mikkeli, Finland
4. Department of Vascular Surgery, Kuopio University Hospital, Kuopio, Finland
5. Kuopio University Computing Centre, Kuopio, Finland