Volume 87, Issue 5, Pages 1046-1054 (May 2015) Increased plasma catalytic iron in patients may mediate acute kidney injury and death following cardiac surgery  David E. Leaf, Mohan Rajapurkar, Suhas S. Lele, Banibrata Mukhopadhyay, James D. Rawn, Gyorgy Frendl, Sushrut S. Waikar  Kidney International  Volume 87, Issue 5, Pages 1046-1054 (May 2015) DOI: 10.1038/ki.2014.374 Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 1 Plasma catalytic iron levels—no RRT/survived versus RRT/death. †P<0.001, †††P<0.05 for within-group comparisons to preoperative (Pre-op) levels; *P<0.01 for between-group comparisons at individual time points. N=228 (no RRT/survived); N=22 (RRT/death). Bars represent median (25–75th interquartile range (IQR)). CPB, cardiopulmonary bypass; POD, postoperative day; RRT/death, renal replacement therapy or in-hospital mortality. Kidney International 2015 87, 1046-1054DOI: (10.1038/ki.2014.374) Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 2 Plasma and urinary iron markers—no RRT/survived versus RRT/death. All iron markers were measured in plasma except neutrophil gelatinase-associated lipocalin (NGAL), which was measured in urine. †P<0.001, ††P<0.01, and †††P<0.05 for within-group comparisons to preoperative (Pre-op) levels; *P<0.01 for between-group comparisons at individual time points. N=228 (no RRT/survived); N=22 (RRT/death). Bars represent median (25–75th interquartile range (IQR)). CPB, cardiopulmonary bypass; POD, postoperative day; RRT/death, renal replacement therapy or in-hospital mortality. Kidney International 2015 87, 1046-1054DOI: (10.1038/ki.2014.374) Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 3 Association between quartiles of catalytic iron on postoperative day 1 (POD 1) and adverse outcomes. *P<0.05 and **P<0.01, after adjustment for age and preoperative estimated glomerular filtration rate (eGFR). Catalytic iron quartiles (μmol/l): quartile 1 (0.19–0.28); quartile 2 (0.28–0.33); quartile 3 (0.33–0.46); and quartile 4 (0.46–4.96). AKI, acute kidney injury; RRT/death, renal replacement therapy or in-hospital mortality. Kidney International 2015 87, 1046-1054DOI: (10.1038/ki.2014.374) Copyright © 2015 International Society of Nephrology Terms and Conditions

Figure 4 Blood transfusions, catalytic iron, and free hemoglobin. Number of packed red blood cell (pRBC) transfusions and (a) plasma catalytic iron levels and (b) plasma free hemoglobin levels on postoperative day 3 (POD 3). Bars represent median (25–75th interquartile range). Kidney International 2015 87, 1046-1054DOI: (10.1038/ki.2014.374) Copyright © 2015 International Society of Nephrology Terms and Conditions