Predictive risk factors of acute kidney injury after on-pump coronary artery bypass grafting.

Background: Acute kidney injury (AKI) is a common complication after coronary artery bypass grafting (CABG) and increases the risk of short and long-term morbidity and mortality. The aim of our study is to identify preoperative and intraoperative risk factors for development of AKI after primary isolated on-pump CABG.

Methods: In the retrospective study, 210 consecutive patients who underwent primary isolated on-pump CABG from January 2007 to March 2016 were included. The patients were divided into without AKI group (Group 1) and AKI group (Group 2) after operation. The s-Cr levels were recorded pre and postoperatively. The demographics, preoperative and postoperative data were collected from patient's medical profile and analyzed statistically.

Results: AKI developed in 40.5% of the patients (85 patients out of 210 patients). Age (Group 1; Group 2, 63.7±8.6; 67.2±8.2, P=0.004), body surface area (BSA) (Group 1; Group 2, 1.71±0.16; 1.64±0.16, P=0.003), body weight (Group 1; Group 2, 64.1±10.0; 60.7±10.2, P=0.017) were statistically significant for the development of AKI. However, preoperative hemoglobin, blood urea nitrogen (BUN), creatinine, estimated glomerular filtration rate (eGFR) and C-reactive protein (CRP) were not significant. As intraoperative factors, total pump time (TPT), aortic cross clamp time and transfusion were not significant. Female gender (OR 1.88; P=0.044), preoperative proteinuria (OR 2.711; P=0.011) and emergent operation (OR 2.641; P=0.035) were risk factors in univariate analysis. Preoperative proteinuria (OR 2.396; P=0.035) was only risk factor in multivariate analysis.

Conclusions: Preoperative proteinuria was an independent predictor of postoperative AKI in patients undergoing primary isolated on-pump CABG. The accurate risk prediction of AKI after surgery can help clinicians manage more effectively in high-risk patients.