1. Department of Cardiac Surgery, Medical Faculty and University Hospital, Heinrich-Heine-University Medical School , Duesseldorf, Germany
2. Department of Cardiac Surgery, Medical Faculty and RWTH University Hospital Aachen, RWTH Aachen University , Aachen, Germany
3. Division of Cardiology, Pulmonology and Vascular Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf , Duesseldorf, Germany