Received: 14 May 2019
Accepted: 14 August 2019
First Online: 11 September 2019
Ethics approval and consent to participate
: This study was approved by the Biomedical Ethics Committee of Peking University International Hospital (NO 2018-029). All procedures performed in this study were in accordance with the ethical standards of the ethics committee. All patients and appointed agents signed the operation agreements and related documents.
: Written informed consents were obtained from all patients or their legally authorized representatives, and privacy of patients was effectively protected.
: The authors declare that they have no competing interests.