Received: 26 November 2018
Accepted: 20 December 2018
First Online: 30 January 2019
Ethics approval and consent to participate
: The study protocol and access to patient records were approved by the Institutional Review Board of Seoul National University (S-D20170024), Seoul, Korea.
: Written informed consent was obtained from the patients for the publication.
: The authors declare that they have no competing interests.
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