Preoperative long-term use of renin-angiotensin-aldosterone system blockers increases the risk of acute kidney injury after coronary artery bypass grafting

Objectives The effect of preoperative renin-angiotensin-aldosterone system (RAAS) blockers on acute kidney injury (AKI) after cardiac surgery remains controversial. This study aimed to evaluate the effect of long-term RAAS blocker use on AKI incidence following coronary artery bypass grafting (CABG).Methods Patients undergoing CABG were included in this retrospective cohort study and divided into control group and medication group. The primary outcome was AKI, while secondary outcomes included the initiation of renal replacement therapy, duration of intensive care unit and total hospitalization, invasive ventilation time, and intraoperative blood pressure conditions. Propensity score matching (PSM) was used to correct for imbalances in baseline characteristics between the groups. Lasso regression and multivariate logistic regression were employed to control for confounding factors and to validate the correlation between medication and AKI. Subgroup and interaction analyses were conducted to examine the heterogeneity of the effect across subgroups. Finally, mediation effect analysis was used to explore potential mechanisms and pathways.Results A total of 317 patients were included in the study, with 184 in the control group and 133 in the medication group. After PSM, matched cohorts were achieved. The medication group had a higher AKI incidence (24.8% versus 10.5%, p = 0.002) and lower minimum intraoperative diastolic blood pressure (38 ± 7 versus 40 ± 6, p = 0.014). Logistic regression confirmed a significant association between RAAS blocker use and AKI risk. Subgroup and interaction analyses demonstrated consistent effects across subgroups.Conclusion Preoperative long-term use of RAAS blockers significantly increases the risk of AKI in patients undergoing CABG.