Received: 8 February 2019
Accepted: 26 March 2019
First Online: 17 April 2019
Ethics approval and consent to participate
: Informed consent had been obtained from patients or their legal representatives from all study participants before inclusion. The study protocol was approved by the local Research Ethics Committee (Hamburg Chamber of Physicians: reference PV4550).
: Not applicable.
: The authors declare that they have no competing interests.
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