In-Hospital Mortality and Associated Risk Factors in Cardiac Surgery-Related Perioperative Acute Kidney Injury Patients Treated with Continuous Renal Replacement Therapy: A Retrospective Cohort Study.

OBJECTIVE

To identify independent risk factors for in-hospital mortality in cardiac surgery-related perioperative acute kidney injury (CS-AKI) patients treated with continuous renal replacement therapy (CRRT) and to compare the predictive performance of the SOFA, APACHE II, and EuroSCORE II scores.

DESIGN

Single-center retrospective cohort study.

SETTING

The study was conducted in the cardiac surgery intensive care unit (ICU) of the General Hospital of Northern Theater Command.

PARTICIPANTS

We included consecutive adult patients (age ≥18 years) who underwent various types of cardiac surgery (including coronary artery bypass grafting, valve surgery, aortic surgery, and heart transplantation) and developed perioperative AKI requiring CRRT between November 1, 2013, and July 30, 2022. Patients with chronic kidney disease stage 4-5 or receiving maintenance hemodialysis were excluded.

INTERVENTIONS: None. All patients included in the study developed perioperative AKI requiring CRRT, with the timing and indications for CRRT initiation jointly evaluated by cardiac surgeons and nephrologists. No additional study-specific interventions were performed.

MEASUREMENTS & MAIN

RESULTS

Baseline characteristics, perioperative parameters, and CRRT initiation data were extracted from the patients' electronic medical records. Cox regression analysis was used to identify mortality risk factors, and receiver operating characteristic (ROC) curves were constructed to evaluate the predictive efficacy of the SOFA, APACHE II, and EuroSCORE II scores. The in-hospital mortality rate was 50.5%. Multivariable Cox regression revealed that each 1-point increase in the SOFA score was associated with a 46% increase in mortality risk (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.36-1.56). Intra-aortic balloon pump (IABP) use (HR, 2.11; 95% CI, 1.30-3.42) and mechanical ventilation time >96 hours (HR, 3.06; 95% CI, 1.82-5.15) also were independent predictors of in-hospital mortality. ROC analysis demonstrated that the SOFA score had significantly greater predictive accuracy for in-hospital mortality (area under the curve [AUC], 0.93) compared to the APACHE II (AUC, 0.72) and EuroSCORE II (AUC, 0.61) scores.

CONCLUSION

The SOFA score at CRRT initiation serves as an independent predictor of in-hospital mortality in CS-AKI patients requiring CRRT, outperforming both the APACHE II score and the EuroSCORE II score. IABP use and a mechanical ventilation time >96 hours also were independent predictors of in-hospital mortality. These findings may support early risk stratification and guide clinical decision making in this high-risk population.