SAN DIEGO – Among patients undergoing cardiac bypass surgery, perioperative use of corticosteroids did not alter the risk of acute kidney injury, results from a large randomized trial showed.
“Worldwide, over 20 million cardiac surgeries are done each year, but 4 million are complicated by acute kidney injury, and 200,000 are complicated by severe kidney injury treated with dialysis,” Dr. Amit X. Garg said during a press briefing at the annual meeting of the American Society of Nephrology. “So certainly people would benefit from a therapy to prevent acute kidney injury (AKI) and improve the safety of surgery.”
Dr. Amit X. Garg
Dr. Garg, a nephrologist at the London Health Sciences Centre in London, Ontario, Canada, noted that cardiopulmonary bypass initiates a systemic inflammatory response syndrome, “which activates complement, inflammatory cytokines, and other inflammatory mediators, which in turn increases endothelial permeability, organ damage, and increased morbidity and mortality, including acute kidney injury.” Researchers are interested in corticosteroids, “because they suppress this inflammatory response. In other settings, such as acute glomerulonephritis, we successfully use corticosteroids to treat acute inflammation in the kidney,” he said.
In a study known as the Steroids in caRdiac Surgery Trial (SIRS), researchers at 79 centers in 18 countries set out to investigate if methylprednisolone alters the risk of acute kidney injury in patients undergoing cardiac surgery with cardiopulmonary bypass. Between June 2007 and December 2013, 7,286 patients were randomized to intravenous methylprednisolone 250 mg at anesthetic induction and 250 mg at initiation of coronary bypass, or placebo.
AKI was defined as a 0.3 mg/dL increase or greater in postoperative serum creatinine concentration from the preoperative concentration within 14 days following surgery, or a 50% increase from the preoperative value within 14 days following surgery. Secondary outcomes included different stages of AKI and receipt of acute dialysis in the 30 days following surgery. Patients, caregivers, and researchers were blinded to the treatment allocation.
Of the 7,286 patients, 3,647 received methylprednisolone and 3,639 received placebo. The mean age of patients was 60 years, 60% were men, 26% were diabetic, and 25% of patients had combined CABG and valve surgery.
The SIRS Investigators reported that the risk of AKI was similar among patients who received methylprednisolone and those who received placebo (40.9% vs. 39.5%, respectively; relative risk 1.03). Results were similar across multiple categorical definitions of AKI, including AKI or death (41.5% vs 40.2%; RR 1.03); AKI stage of 2 or greater (9.9% vs 9.9%; RR 1.01); AKI stage of 3 or greater (4% vs. 4.5%; RR .89), and being on acute dialysis (2.6% vs. 2.4%; RR 1.08).
“There was no benefit of steroids on the risk of AKI in those with or without preoperative chronic kidney disease,” Dr. Garg said. “The result was also not different in the subpopulation of patients with AKI as defined by Kidney Disease Improving Global Outcomes.” Results from SIRS “would suggest that patients undergoing cardiac surgery with cardiopulmonary bypass should not use prophylactic steroids to prevent AKI. When we consider the side effect profile, the most clinically relevant outcomes, and apply the GRADE framework [the Grading of Recommendations Assessment, Development, and Evaluation] to the available evidence, we would recommend that steroids not be used in this way, with a grade 1B recommendation.”
The study was sponsored by the Population Health Research Institute in Hamilton, Ontario and the Canadian Institutes of Health Research. Dr. Garg reported having no relevant financial disclosures for this study.