[1] Landspitali Univ Hosp, Div Nephrol, Dept Med, IS-101 Reykjavik, Iceland
[2] Univ Iceland, Dept Physiol, Sch Hlth Sci, Reykjavik, Iceland
[3] Univ Iceland, Fac Med, Sch Hlth Sci, Reykjavik, Iceland
[4] Landspitali Univ Hosp, Cardiovasc Res Ctr, IS-101 Reykjavik, Iceland
[5] Landspitali Univ Hosp, Dept Cardiothorac Surg, IS-101 Reykjavik, Iceland
[6] Landspitali Univ Hosp, Childrens Med Ctr, IS-101 Reykjavik, Iceland