1. Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School , Hannover, Germany
2. Medical Faculty of St-Petersburg State University , St-Petersburg, Russia
3. Department of Cardiac surgery, Heidelberg Medical School , Heidelberg, Germany
4. German Centre for Lung Research, Biomedical Research in End-stage and Obstructive Lung Disease Hannover , Hannover, Germany
5. Department of Respiratory Medicine, Hannover Medical School , Hannover, Germany
6. Department of Cardiac Surgery, University Hospital Düsseldorf , Düsseldorf, Germany