Acute kidney injury after surgery for congenital heart disease

Background: The RIFLE criteria (risk, injury, failure, loss, and end-stage kidney disease) have been used to assess acute kidney injury (AKI) in various populations of critically ill children. There are limited reports of AKI using RIFLE criteria in large pediatric populations undergoing congenital heart disease surgery. Methods: Records of patients 18 years and younger who underwent surgery for congenital heart disease between January 2006 and November 2009 were reviewed. The RIFLE score was determined for each patient postoperatively. Multivariate logistic regression analyses were performed to determine risk factors for AKI and the association with clinical outcomes, with subanalyses of patients 1 month of age or younger. Results: Data for 458 patients (median age, 7.6 months) were collected and analyzed. Evidence of AKI was demonstrated in 234 patients (51%), the vast majority of whom recovered within 48 hours. Younger age, higher RACHS-1 (risk-adjusted classification for congenital heart surgery) category, and longer cardiopulmonary bypass time were associated with development of AKI. Acute kidney injury was associated with longer duration of ventilation and lengths of intensive care unit and hospital stay. Incidence of AKI in patients 1 month of age or younger was 60.9%, of which more than half required greater than 72 hours to recover. In patients 1 month of age or younger, use of cardiopulmonary bypass, lower preoperative serum creatinine, and higher preoperative blood urea nitrogen were associated with AKI, and AKI was the only factor associated with longer intensive care unit and hospital lengths of stay. Conclusions: Incidence of AKI based on RIFLE criteria in patients undergoing congenital heart disease surgery is higher than previously reported. Risk factors include age 1 month or younger and use of cardiopulmonary bypass. Acute kidney injury is associated with longer lengths of stay.