Funding for this research was provided by:
National Natural Science Foundation of China (81272651 and 81570180)
Received: 5 February 2018
Accepted: 6 May 2018
First Online: 22 May 2018
Ethics approval and consent to participate
: This study received approval from the Ethics Committee of the Xijing Hospital [KY20173326–1]. Additional informed consent was not required by the ethics committee for this retrospective study.
: The authors declare that they have no competing interests.
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