Risk Factors and Prognosis of Acute Kidney Injury after Cardiac Surgery in Patients with Chronic Kidney Disease.

INTRODUCTION: Cardiac surgery-associated acute kidney injury (CSA-AKI) is one of the most prevalent complications of cardiac surgery, while the renal and overall prognoses of chronic kidney disease (CKD) patients with CSA-AKI are extremely poor. However, there is little published information on the occurrence of CSA-AKI in patients with CKD. The purpose of this study was to investigate the risk factors and prognostic factors of cardiac surgery-related AKI in patients with CKD.

METHODS: A retrospective study was performed on CKD patients who underwent cardiac surgery at a tertiary referral teaching hospital. CSA-AKI was defined based on the KDIGO criteria. The risk factors for CSA-AKI and the factors affecting renal function recovery at discharge or death in patients with AKI were investigated.

RESULTS: Among 1638 CKD patients enrolled, the incidence of CSA-AKI was 50.55%. AKI patients' in-hospital mortality was higher than patients without AKI (AKI vs. no AKI, 4.7 vs. 0.9%, p < 0.001). Multivariate logistic regression analysis showed that male (odds ratio [OR] 1.479), preoperative hypertension (OR 1.548), preoperative hemoglobin <110 g/L (OR 2.389), and aortic clamping time >58 min (OR 1.567) were independent risk factors for AKI after cardiac surgery in patients with CKD. Factors affecting renal function recovery of AKI patients included preoperative diabetes mellitus (OR 0.306), hyperchloremia (OR 0.927), estimate of the glomerular filtration rate (OR 1.034), and AKI progression. Compared with patients with AKI stage 1, the rate of renal function recovery in patients with AKI stage 2 and stage 3 was reduced by 78.9% and 82.3%, respectively.

CONCLUSIONS: In the population of patients with CKD, the incidence of CSA-AKI was high, which significantly affected renal and overall prognosis. The prompt intervention of modifiable factors may help improve the prognosis of patients with CKD.