Data from the Edinburgh Royal Infirmary indicates that acute kidney injury (AKI) affects ~10% of patients undergoing cardiac surgery. AKI is associated with a >9-fold increased risk of death and no protective treatments are available. The drug hemearginate potently induces the highly protective enzyme hemeoxygenase-1 and confers strong protection in experimental AKI in mice (Ferenbach et al Kidney International 2011). This project will be the first trial of hemearginate treatment in patients about to undergo cardiac surgery and at high risk of developing subsequent AKI. It will determine drug safety, hemeoxygenase-1 induction and biomarkers of kidney function post operatively.