No Reduction in Cardiac Surgery–Related AKI with Spironolactone

The mineralocorticoid receptor blocker spironolactone does not reduce the risk of acute kidney injury (AKI) in patients undergoing cardiac surgery, concludes a trial in American Journal of Kidney Diseases.

The randomized, double-blind trial included 233 adults (mean age 53) undergoing cardiac surgery with cardiopulmonary bypass. Starting the day before surgery, one group received spironolactone—100 mg, with three further 25 mg doses given on postoperative days 0, 1, and 2—while the other group received placebo. Patient characteristics were similar between groups: mean serum creatinine level was 0.9 mg/d, while the median Thakar score (used to estimate AKI risk) was 2. Patients were followed up for 7 days, or until ICU discharge.

Acute kidney injury occurred in 43% of patients assigned to spironolactone versus 29% in the placebo group. The difference was not significant on adjusted analysis, although “the odds ratio showed a propensity toward risk.”

The spironolactone and placebo groups had a similar incidence of stage 2 and 3 AKI. Secondary outcomes were also similar, including renal replacement therapy, length of ICU stay, and mortality.

Aldosterone could play a role in kidney injury during renal ischemia. In rat models, the authors have found that spironolactone can prevent renal injury induced by ischemia-reperfusion.

However, this randomized trial finds no renoprotective effect of spironolactone in reducing the risk of AKI after cardiac surgery. However, it suggests a possible trend toward increased risk. The authors discuss possible reasons for the discordant results from their preclinical studies [Barba-Navarro R, et al. The effect of spironolactone on acute kidney injury after cardiac surgery: a randomized, placebo-controlled trial. Am J Kidney Dis 2017; 69:192–199].