Received: 19 November 2018
Accepted: 22 January 2019
First Online: 31 January 2019
Ethics approval and consent to participate
: The implementation of this study, with the protocol number 2019/2016, was approved by the institutional ethics committee of the Medical University of Vienna. Due to the retrospective character of the study a consent to participated was not required according to the decision of the ethics committee.
: Not applicable.
: The authors declare that they have no competing interests.
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