Received: 12 September 2017
Accepted: 8 October 2018
First Online: 22 October 2018
Ethics approval and consent to participate
: This retrospective study was conducted in accordance with the ethical standards of the declaration of Helsinki and approved by the Ethics Committee of Yokohama Municipal Citizen’s Hospital, Kanagawa, Japan (Approval Number: 17–11-06). The requirement for informed consent was waived due to the retrospective nature of the study.
: Not applicable.
: The authors declare that they have no competing interests.
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