Received: 8 January 2018
Accepted: 27 November 2018
First Online: 10 December 2018
Ethics approval and consent to participate
: The study protocol was approved by the Institutional Review Board of Konkuk University Medical Center and Asan Medical Center and was conducted in accordance with the amended Declaration of Helsinki. All participants provided written informed consent before enrollment.
: Not applicable
: The authors declare that they have no competing interests.
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