Received: 30 September 2017
Accepted: 27 February 2018
First Online: 5 March 2018
Ethics approval and consent to participate
: The study was approved by the Paris North Hospitals Institutional Review Board (Paris VII University, AP-HP, IRB No. 00006477). According to French law, no informed consent was required in view of the observational and retrospective nature of this study.
: Not applicable.
: The authors declared that they have no competing interests.
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