Preoperative Statins and Acute Kidney Injury After Cardiac Surgery: Utilization of a Consensus Definition of Acute Kidney Injury

studies have shown the inci-dence of acute kidney injury in pa-tients undergoing cardiac surgery to be between 1.5 % and 43%.1-5 Overall, 0.33-4.2 % of patients in these studies have re-quired postoperative renal replacement therapy (RRT).1-5 Cardiac surgery pa-tients who develop acute kidney injury with or without the need for RRT are at risk of increased morbidity and mortali-ty. In-hospital mortality was reported by Bove and colleagues to be as high as 46.2%,1 while the mortality rate in pa-tients requiring RRT was 82 % in a study by Palomba et al.6 Several risk factors, including the use of cardiopulmonary bypass,7 have been identified for the de-velopment of acute kidney injury in car-diac surgery patients.8 However, useful interventions to reduce the incidence are still being sought. Previous studies have evaluated the association of preoperative use of statins with the incidence of acute kidney injury following cardiac surgery as a possible preventive therapy.9-13 The rationale for such a benefit in this population comes from findings that statins decrease in-flammatory cytokines, reduce postopera-tive thrombocytosis, increase neutrophil apoptosis, and upregulate endothelial ni-tric oxide synthetase.14-16 In a study con-ducted by Tabata and colleagues, a 61 % decrease in the odds of acute kidney injury with preoperative statins was observed in a propensity-matched cohort.10 However, other studies have found no significant association.9,11-13 All of these studies were limited, as most enrolled only patients undergoing isolated coronary artery bypass graft (CABG) surgery,9,10,12,13 while the other enrolled only patients under