Received: 20 November 2017
Accepted: 9 April 2018
First Online: 16 April 2018
Ethics approval and consent to participate
: This study was reviewed and approved by the Ethics Committee of Beijing Chaoyang Hospital. Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
: The authors declare that they have no competing interests.
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