1. Department of Cardiovascular Surgery, University Heart Centre Freiburg, University Medical Centre Freiburg , Südring 15, 79189 Bad Krozingen, Freiburg , Germany
2. Faculty of Medicine, Albert-Ludwigs-University of Freiburg , Breisacher Strasse 153, 79110 Freiburg , Germany
3. Department of Diagnostic and Interventional Radiology, University Medical Centre Freiburg , Freiburg , Germany