Kidney international
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Kidney international · May 2015
Increased plasma catalytic iron in patients may mediate acute kidney injury and death following cardiac surgery.
Catalytic iron, the chemical form of iron capable of participating in redox cycling, is a key mediator of acute kidney injury (AKI) in multiple animal models, but its role in human AKI has not been studied. Here we tested in a prospective cohort of 250 patients undergoing cardiac surgery whether plasma catalytic iron levels are elevated and associated with the composite outcome of AKI requiring renal replacement therapy or in-hospital mortality. Plasma catalytic iron, free hemoglobin, and other iron parameters were measured preoperatively, at the end of cardiopulmonary bypass, and on postoperative days 1 and 3. ⋯ In multivariate analyses adjusting for age and preoperative eGFR, patients in the highest compared with the lowest quartile of catalytic iron on postoperative day 1 had a 6.71 greater odds of experiencing the primary outcome, and also had greater odds of AKI, hospital mortality, and postoperative myocardial injury. Thus, our data are consistent with and expand on findings from animal models demonstrating a pathologic role of catalytic iron in mediating adverse postoperative outcomes. Interventions aimed at reducing plasma catalytic iron levels as a strategy for preventing AKI in humans are warranted.
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Kidney international · May 2015
Randomized Controlled TrialAssociation between strict blood pressure control during chronic kidney disease and lower mortality after onset of end-stage renal disease.
There is controversy regarding whether strict blood pressure control is indicated in chronic kidney disease (CKD) since the primary results of randomized controlled trials failed to show any impact on progression of kidney disease with this strategy. However, strict blood pressure control may have other beneficial effects beyond reducing the risk of end-stage renal disease (ESRD), such as lowering mortality after ESRD onset. The Modification of Diet in Renal Disease (MDRD) trial randomized 840 patients with CKD to strict (mean arterial pressure under 92 mm Hg) versus usual (mean arterial pressure under 107 mm Hg) blood pressure control between 1989 and 1993. ⋯ Overall, there were 212 deaths in the strict blood pressure control arm and 233 deaths in the usual arm (significant unadjusted hazard ratio for death 0.82 (95% CI 0.68-0.98)). Thus, although strict blood pressure control did not delay progression of CKD to ESRD, this strategy was associated with a lower risk of death after ESRD. Hence, long-term post-ESRD outcomes should be considered when formulating blood pressure targets for CKD.