Anaesthesia
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Observational Study
Pre-operative anaemia, intra-operative hepcidin concentration and acute kidney injury after cardiac surgery: a retrospective observational study.
Acute kidney after cardiac surgery is more common in anaemic patients, whereas haemolysis during cardiopulmonary bypass may lead to iron-induced renal injury. Hepcidin promotes iron sequestration by macrophages: hepcidin concentration is reduced by anaemia and increased by inflammation. We analysed the associations in 525 patients between pre-operative anaemia (haemoglobin < 130 g.l-1 in men and < 120 g.l-1 in women), intra-operative hepcidin concentration and acute kidney injury (dialysis or > 26.4 μmol.l-1 or > 50% creatinine increase during the first two days after cardiac surgery. ⋯ Contrary to generally increased rates of kidney injury in patients with higher hepcidin concentrations, rates of kidney injury in anaemic patients were lower in patients with higher hepcidin concentrations, beta-coefficient (SE) -0.037 (0.01), p = 0.007. In cardiac surgical patients the rate of postoperative acute kidney injury predicted by the Cleveland risk score might be adjusted for pre-operative anaemia and intra-operative cardiopulmonary bypass time and hepcidin concentration. Pre-operative correction of anaemia, reduction in intra-operative bypass time and modification of iron homeostasis and hepcidin concentration might reduce acute kidney injury.