Received: 10 June 2019
Accepted: 21 January 2020
First Online: 30 January 2020
Ethics approval and consent to participate
: This study was approved by our institutional review board of the Jikei University School of Medicine, Ethics Committee No. (30–275 ). As this was a retrospective study, the need for informed consent was waived.
: Not applicable.
: All authors report no competing interests.