1. Department of Vascular Surgery, University Hospital of Bern , Bern, Switzerland
2. Department of Vascular Surgery, University Hospital of Turku , Turku, Finland
3. Department of Vascular Surgery, Satakunnan keskussairaala , Pori, Finland
4. Department of Cardiac Surgery, University Hospital of Bern , Bern, Switzerland
5. Department of Thoracic and Cardiovascular Surgery, University Medical Center , Tübingen, Germany