1. Department of Cardiac Surgery, Children's Hospital, Zürich, Switzerland
2. Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
3. Department of Cardiothoracic and Vascular Surgery, University of Mainz, Mainz, Germany
4. Department of Cardiovascular Surgery, Heart Center Freiburg University, Freiburg, Germany
5. Department of Cardiovascular Surgery, Heinrich Heine University, Düsseldorf, Germany
6. Department of Cardiac Surgery, University Hospital Leipzig, Leipzig, Germany
7. Department of Cardiac and Thoracic Surgery, University of Regensburg, Regensburg, Germany
8. Kerckhoff Clinic, Bad Nauheim, Germany
9. Cardiac Surgery Clinic, University of Heidelberg, Heidelberg, Germany
10. Department of Cardiac, Thoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
11. Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, and DZHK (German Center for Cardiovascular Research), Berlin, Germany
12. Clinic of Cardiac Surgery, Ludwig Maximilian University, Munich, Germany
13. Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr-University Bochum, Bad Oeynhausen, Germany
14. Clinic for Cardiovascular Surgery, University Hospital Zürich, Zürich, Switzerland
15. University Heart Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany