Predictors of Renal Replacement Therapy in Cardiac Surgery-Associated Acute Kidney Injury Patients: A Single-Centered, Retrospective Study

Abstract

Abstract Background: Studies have reported that cardiac surgery-associated acute kidney injury (CSA-AKI) patients requiring dialysis or renal replacement therapy (RRT) have a higher risk of in-hospital mortality. This study aimed to investigate the predictors contributing to postoperative RRT. Materials and Methods: This retrospective observational study was conducted at a single cardiovascular center. Patients who underwent cardiac surgery complicated with CSA-AKI in the intensive care unit (ICU) from January 2020 to December 2022 were included. They were categorized into two groups: those who required RRT (group A, n = 302) and those who did not (group B, n = 811). Bivariable and multivariable analyzes were conducted to compare the risk with odds ratio (OR) for in-hospital mortality between those groups. Results: We analyzed 1113 patients (29.4%) in the final analysis. The in-hospital mortality rate was 31.8% vs. 4.2% (OR = 10.6, P < 0.001). Variables that significantly predicted postoperative RRT requirements in CSA-AKI patients included female sex (P = 0.038), coronary artery bypass graft (P = 0.001), multiple valves surgery (P = 0.032), diabetes (P = 0.01), renal disease (P = 0.005), postoperative serum creatinine >3.0 mg/dL (P < 0.001), mechanical ventilation use of ≥48 h (P < 0.001), ICU length of stay of >5 days (P < 0.001), use of more than two inotropes and vasoactive agents, (P < 0.001), and postoperative intra-aortic balloon pump (IABP) (P < 0.001). Conclusion: CSA-AKI patients who require dialysis are associated with a higher mortality. Predictors of postoperative RRT included female sex, certain types of surgery, diabetes, postoperative serum creatinine >3.0 mg/dL, mechanical ventilation use of ≥48 h, ICU length of stay of >5 days, use of more than two inotropes and vasoactive agents, and postoperative IABP.