Funding for this research was provided by:
National Natural Science Foundation of China (81870454)
Received: 28 February 2019
Accepted: 3 April 2019
First Online: 16 April 2019
Ethics approval and consent to participate
: This study was reviewed and approved by the Ethics Committee of the First Affiliated Hospital of ZhengZhou University. 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.
: All authors agree to publish this article on this journal.
: All authors declare that they have no conflict of interest.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.