Interleukin-8 and Tumor Necrosis Factor Predict Acute Kidney Injury After Pediatric Cardiac Surgery

Background. Inflammation is a key component of both acute kidney injury (AKI) and response to cardiopulmonary bypass. Because AKI poses risks to children after cardiac surgery, we investigated the value of inflammatory biomarkers interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF alpha) for predicting AKI and other complications. Methods. We enrolled 412 children between the ages of 1 month and 18 years undergoing cardiopulmonary bypass for cardiac surgery. We collected blood both preoperatively and postoperatively (within 6 hours post-surgery) and measured plasma IL-8 and TNF alpha. Results. IL-8 and TNF alpha did not predict AKI in children <2 years, but were strongly associated with AKI in children >= 2 years. There were significant associations between biomarker levels and age (<2 or >= 2 years). In children >= 2 years, patients in the highest tertile of preoperative IL-8 and postoperative TNF alpha had 4.9-fold (95% CI: 1.8-13.2) and 3.3-fold (95% CI: 1.2-9.0) higher odds of AKI compared with those in the lowest tertile. Children <2 years with higher biomarker levels also had higher odds of AKI, but the difference was not significant. We also found that postoperative TNF alpha levels were significantly higher in patients with longer hospital stays, and that both postoperative IL-8 and TNF alpha levels were significantly higher in patients with longer ventilation lengths. There was no evidence that biomarker levels mediated the association between AKI and length of ventilation; they appear to be independent predictors. Conclusions. Preoperative IL-8 and postoperative TNF alpha are significantly associated with higher odds of AKI and greater lengths of hospital stays and ventilator use in children 2 years and older. (C) 2017 by The Society of Thoracic Surgeons