Received: 7 March 2019
Accepted: 22 May 2019
First Online: 28 May 2019
Ethics approval and consent to participate
: The responsible local ethics committee (Stuttgart, Germany) approved this study, and written informed consent was obtained from each patient prior to their inclusion.
: Not applicable.
: Gerhard Schymik (GS) and Holger Schröfel (HS) are proctors, and Peter Bramlage (PB) is a consultant for Edwards Lifesciences. No competing interests was declared by the other authors.