Predictors of postoperative acute kidney injury after coronary artery bypass graft surgery

Abstract Objective: The aims of this study were to identify the risk factors associated with acute kidney injury (AKI) after isolated surgical revascularization with cardiopulmonary bypass and to develop a model to predict the appearance of postoperative AKI. Methods: A total of 435 adult patients who underwent primary isolated coronary artery bypass graft (CABG) surgery, from 2012 to 2016, in the Clinic University Hospital of Valladolid (Spain) were enrolled. AKI was defined according to the risk, injury, failure, loss, and end-stage (RIFLE) criteria. Data were collected from hospital electronic medical records. Multiple logistic regression analysis was used to identify risk factors. Results: The prevalence of AKI was 12.4%. Multivariate analysis identified age (odds ratio [OR], 1.056; 95% confidence interval [CI], 1.016-1.098; P=0.005), hypertension (OR, 3.078; 95% CI, 1.151-8.230; P=0.018), low ejection fraction (EF) (OR, 6.785; 95% CI, 2.080-22.135; P=0.001), estimated glomerular filtration rate (eGFR) (OR, 1.017; 95% CI, 1.005-1.028; P=0.014), EuroSCORE II (OR, 1.049; 95% CI, 1.004-1.096; P=0.033), and no intake of calcium-channel blockers (CCB) (OR, 4.892; 95% CI, 1.496-16.025; P=0.022) as risk factors for AKI. These risk factors were included in a model to predict postoperative AKI with an area under a receiver operating characteristic curve of 0.783±0.036 (95% CI, 0.713-0.854; P<0.0001). Conclusion: Age, hypertension, low EF, eGFR, EuroSCORE II, and no intake of CCB were independent risk factors for postoperative AKI. These factors provide an easy and accurate model to predict postoperative AKI in patients undergoing cardiac surgery.

Cardiac surgery‑associated acute kidney injury.

Cardiac surgery‑associated acute kidney injury (CSA‑AKI) is a well‑recognized complication resulting with the higher morbid‑mortality after cardiac surgery. In its most severe form, it increases the odds ratio of operative mortality 3–8‑fold, length of stay in the Intensive Care Unit and hospital, and costs of care. Early diagnosis is critical for an optimal treatment of this complication. Just as the identification and correction of preoperative risk factors, the use of prophylactic measures during and after surgery to optimize renal function is essential to improve postoperative morbidity and mortality of these patients. Cardiopulmonary bypass produces an increased in tubular damage markers. Their measurement may be the most sensitive means of early detection of AKI because serum creatinine changes occur 48 h to 7 days after the original insult. Tissue inhibitor of metalloproteinase‑2 and insulin‑like growth factor‑binding protein 7 are most promising as an early diagnostic tool. However, the ideal noninvasive, specific, sensitive, reproducible biomarker for the detection of AKI within 24 h is still not found. This article provides a review of the different perspectives of the CSA‑AKI, including pathogenesis, risk factors, diagnosis, biomarkers, classification, postoperative management, and treatment. We searched the electronic databases, MEDLINE, PubMed, EMBASE using search terms relevant including pathogenesis, risk factors, diagnosis, biomarkers, classification, postoperative management, and treatment, in order to provide an exhaustive review of the different perspectives of the CSA-AKI.