Received: 21 November 2019
Accepted: 24 July 2020
First Online: 16 August 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Nankai University Nankai Hospital (NKYY_YX_IRB_2018_002_01). As the study was retrospective, no informed consent was requested.
: Not applicable.
: The authors have no conflicts of interest to disclose.