Funding for this research was provided by:
National Natural Science Foundation of China (81801865, 81671690)
Natural Science Foundation Research Program in Shannxi Province (2019JQ-700, 2019JM-191)
Article History
Accepted: 8 May 2020
First Online: 25 May 2020
Compliance with ethical standards
:
: The authors declared no conflict of interest.
: This study was approved by the institutional review boards of the relevant centers. The requirement for informed patient consent was waived for this retrospective study.
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