Received: 26 November 2019
Accepted: 27 March 2020
First Online: 15 April 2020
Ethics approval and consent to participate
: This study was approved by the Medical Ethics Committee (The Fifth Affiliated Hospital, Sun Yat-sen University), and an exemption from informed consent was obtained from our responsible Investigational Ethics Review Board.
: Not applicable.
: The authors declare that they have no conflict of interest.