1. Department of Cardiothoracic Surgery, Jena University Hospital, Friedrich Schiller University, Jena, Germany
2. Department of Cardiology and Angiology, University of Leipzig, Leipzig, Germany
3. Department of Vardiac Surgery, Center of Cardiovascular Diseases Rotenburg a. d. Fulda, Rotenburg, Germany
4. Department of Cardiac Surgery, Hospital Bogenhausen, Munich, Germany