Funding for this research was provided by:
Medical University of Vienna
Received: 15 January 2018
Accepted: 27 April 2018
First Online: 15 May 2018
Compliance with ethical standards
: All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments.
: For this type of study formal consent is not required.