1. Faculty of Health, University of Witten, Witten, Germany
2. Department of Cardiac, Thoracic, Transplant, and Vascular Surgery, Hannover Thoracic Transplant Program, Hannover Medical School, Hannover, Germany
3. University Medical Center Freiburg, Freiburg, Germany
4. School of Nursing and Health Studies, University of Missouri-Kansas City, Kansas City, MO, USA