Article History
Received: 12 November 2019
Accepted: 25 December 2019
First Online: 9 January 2020
Ethics approval and consent to participate
: This study is a retrospective analysis; it was extensively discussed at relevant department and agreed unanimously for publication. According to regulations of the Board of Ethics Committee, Ruijin Hospital, ethics approval letter is not mandatory for retrospective analysis and publication of the existing data. Hence, this study met the criteria for publication.
: The manuscript does not contain any individual person’s data.
: The authors declare that they have no competing interests.