1 Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, University Hospital Ruhr-University Bochum, Bad Oeynhausen, Germany. Electronic address: mdeutsch@hdz-nrw.de.
2 Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, University Hospital Ruhr-University Bochum, Bad Oeynhausen, Germany.