Received: 13 March 2018
Accepted: 2 October 2018
First Online: 26 October 2018
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University (No. 20130802GS-9). Written informed consent to participate was obtained from all patients.
: Not applicable
: The authors declare that they have no competing interest.
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