**5. Conclusions**

In conclusion, the study findings sugges<sup>t</sup> that AKI observed in EPT with conservatively managed HS PDA is not a pathological entity and might reflect a physiological postnatal developmental process of the immature renal system.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2077-0383/9/3/699/s1, Figure S1: Time course of the mean serum creatinine levels between infants with HS (hemodynamically significant) PDA (patent ductus arteriosus) and those with Non HS PDA for 60 days of life.

**Author Contributions:** Conceptualization, E.S.S., S.I.S. and W.S.P.; methodology, Y.S.C. and W.S.P.; software, E.S.S.; validation, S.Y.A.; formal analysis, E.S.S. and S.I.S.; resources, S.I.S. and W.S.P., data curation, E.S.S. and S.Y.A.; writing—original draft preparation, E.S.S. and S.I.S.; writing—review and editing, Y.S.C. and W.S.S.; visualization, E.S.S.; supervision, Y.S.C. and W.S.P.; project administration, E.S.S. and S.I.S. All authors have read and agree to the published version of the manuscript.

**Funding:** This research was funded by grants of the 20 by 20 Project (Best #3, GFO1150091) from Samsung Medical Center.

**Conflicts of Interest:** The authors declare no conflict of interest.
