Cardiac surgery–associated acute kidney injury (CSA-AKI) is a common complication with high morbidity and mortality. This study was designed to determine whether adding human albumin to the cardiopulmonary bypass (CPB) priming solution reduces the incidence of CSA-AKI.

A double-blind, randomized controlled trial (RCT) involving 248 patients scheduled for cardiac surgery with CPB.

A single-center tertiary university hospital.

Adults with a baseline estimated glomerular filtration rate (eGFR) of ≥60 mL/min/1.73 m² and left ventricular ejection fraction ≥40%.

Patients were randomized to receive either a crystalloid priming solution (Plasma-Lyte) plus 4% albumin (intervention group, n = 126) or a crystalloid solution alone (control group, n = 122) for CPB.

Data analyses were performed using the Chi-square test and Student’s t-test, or their nonparametric equivalent. The primary outcome was the incidence of CSA-AKI, as defined by the Kidney Disease Improving Global Outcomes criteria, within 5 days postoperatively. Both cohorts were comparable in baseline and perioperative characteristics, including preoperative albumin levels. The incidence of CSA-AKI was 29.3% (n = 37) in the intervention group compared with 31.2% (n = 38) in the control group (odds ratio: 0.91, 95% confidence interval: 0.53-1.58). The observed difference in CSA-AKI incidence between the groups was not statistically significant. A post-hoc subgroup analysis of patients with a baseline eGFR of 60 to 70 mL/min/1.73 m² indicated a trend toward a reduced incidence of CSA-AKI in the intervention group compared with the control group (35.7% v 57.6%; odds ratio: 0.41, 95% confidence interval: 0.16-1.03). This trend was not observed in patients with an eGFR greater than 70 mL/min/1.73 m². No significant differences were observed between groups for the need for inotropes or vasoconstrictors, incidence of cardiogenic or distributive shock, bleeding, need for transfusion, or use of nephrotoxic drugs.

Adding albumin to the CPB priming solution did not decrease the incidence of CSA-AKI in patients with normal preoperative renal function. These findings suggest that albumin might benefit patients with impaired renal function, warranting further investigation.