Background

Acute kidney injury (AKI) frequently occurs as a complication of cardiac surgery and cardiopulmonary bypass (CPB). Its prevalence and severity are determined by various preoperative and intraoperative factors. The aim of this study was to examine the risk factors for AKI following on-pump coronary artery bypass grafting (CABG).

Methods

A retrospective analysis of clinical records from a single medical center was performed. The primary determinant for AKI analysis was the creatinine-level changes within the first 48 h after surgery. Records of 120 patients from a prospective cohort study were examined.

Results

An AKI incidence of 26% occurred in the study cohort. The univariate analysis revealed that patients who developed AKI had notably higher EuroSCORE II values (2.00 ± 0.98 vs. 1.49 ± 0.74, p = 0.006) and higher initial levels of urea (7.62 ± 2.94 vs. 6.12 ± 1.71, p = 0.002) and creatinine (0.108 ± 0.039 vs. 0.091 ± 0.016, p = 0.003). Additionally, they exhibited a more frequent occurrence of initial albumin levels below 40 g/l (9 (34.6%) vs. 11 (14.9%) cases, p = 0.030) and a lower initial hemoglobin level (137.8 ± 13.2 g/l vs. 146.6 ± 13.6 g/l, p = 0.005) in comparison to patients without this complication. Moreover, those with AKI had a significantly longer hospital stay duration (14.3 ± 5.45 days vs. 12.6 ± 3.05 days, p = 0.048). Logistic regression indicated one risk factor, oxygen delivery during CPB, that correlated with the onset of AKI in the early postoperative period.

Conclusion

The prevalence of AKI was higher among patients with a higher EuroSCORE II, lower preoperative hemoglobin, increased preoperative levels of creatinine and urea, infrequent albumin levels below 40 g/L, diminished oxygen delivery during CPB, and greater need for RBC transfusion and furosemide, but it did not correlate with the duration of CPB.