Received: 16 July 2017
Accepted: 6 February 2018
First Online: 20 February 2018
Ethics approval and consent to participate
: The study was approved by the ethics committee of Peking University First Hospital (No. 2013).
: Written informed consent for publication was obtained from the patient’s legal guardian and is available for review by the editors of this journal.
: The authors declare that they have no competing interests.
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