Insights on perioperative risk factors, incidence & complications for cardiac surgery - associated acute kidney injury

Abstract

Background
Cardiac surgery-associated acute kidney injury (CSA-AKI) remains a prevalent and serious postoperative complication, with a multifactorial etiology involving patient comorbidities, surgical stress, and inflammatory responses.


Objectives
To identify perioperative risk factors contributing to CSA-AKI, assess the utility of predictive scoring systems, and evaluate associations with clinical outcomes including ICU stay, MV, renal replacement therapy (RRT), and mortality rate .


Methods
This prospective, multicenter, non-randomized study was conducted from January 2024 to June 2025 at Cairo University Hospitals and Ain Shams University Hospitals. A total of 330 adult cardiac surgery patients were enrolled and stratified into AKI and non-AKI groups based on KDIGO criteria. Data were collected on demographics, comorbidities, nephrotoxic drug exposure, renal function, inflammatory biomarkers (CRP, PCT, TLC), intraoperative factors (e.g., CPB time, IABP use), and postoperative outcomes (ICU stay, ventilation duration, mortality). The predictive performance of the Thakar/Cleveland and Jiang scores was evaluated, and logistic regression was used to identify independent predictors of CSA-AKI.


Results

CSA-AKI occurred in 40.6% of patients. This study identifies significant CSA-AKI predictors. Preoperative risk factors included low eGFR (
p
 < 0.001), NYHA ≥ II (
p
 = 0.028), and elevated Thakar and Jiang scores (both
p
 < 0.001). Intraoperatively, longer CPB (131 vs. 80 min,
p
 < 0.001), cross-clamp time (104 vs. 53 min,
p
 < 0.001), and combined CABG + valve surgery (
p
 = 0.030) were associated with AKI. Postoperative predictors included higher CVP (
p
 < 0.001), ICU stay (6 vs. 3 days,
p
 < 0.001), MV duration (16 vs. 6 h,
p
 < 0.001), and CRP/PCT (
p
 < 0.001). AKI patients had 21.2% mortality within 7 days and 44.8% composite 30-day mortality/RRT rate (
p
 < 0.001). Post-op AUC was 0.981 (
p
 < 0.001).



Conclusions
CSA-AKI is influenced by both fixed and modifiable perioperative factors. Timely risk stratification, inflammation monitoring, and tailored perioperative management are crucial to mitigate renal injury and improve outcomes in cardiac surgery patients.