Intravenous amino acid infusion reduces the risk of acute kidney injury (AKI) associated with cardiac surgery, reports a clinical trial in The New England Journal of Medicine.
The randomized, double-blind Intravenous Amino Acid Therapy for Kidney Protection in Cardiac Surgery (PROTECTION) trial included 3511 adults undergoing cardiac surgery with cardiopulmonary bypass, recruited from 22 centers in three countries. Patients assigned to the intervention group received balanced amino acid infusions, up to 2 g/kg of ideal body weight per day, for 3 days. Placebo controls received infusions of Ringer's solution.
Rates of AKI, based on Kidney Disease: Improving Global Outcomes criteria, were compared between groups. Secondary outcomes included AKI severity, need for kidney replacement therapy, and 30-day all-cause mortality.
Amino acid infusions were associated with a significant reduction in the incidence of AKI: 26.9% versus 31.5%; relative risk, 0.85. A stronger protective effect was observed for stage 3 AKI: 1.6% versus 3.0%; relative risk, 0.56. Rates of kidney replacement therapy were 1.4% in both the amino acid group and the control group. Mortality and other secondary outcomes were similar between groups.
Reduced kidney perfusion is a contributing factor to AKI associated with cardiac surgery. By increasing perfusion and recruiting functional reserve, amino acid infusion might reduce the occurrence of AKI in this high-risk group.
The PROTECTION trial found that short-term amino acid infusion reduced AKI risk in patients undergoing cardiac surgery compared with crystalloid infusion. The effect appears greatest in the prevention of severe AKI. The researchers conclude that their findings are “clinically and epidemiologically important,” given the high numbers of patients undergoing cardiac surgery and the risk of adverse outcomes associated with AKI [Landoni G, et al. A randomized trial of intravenous amino acids for kidney protection. N Engl J Med, published online June 12, 2024. doi: 10.1056/NEJMoa2403769].