Acute Kidney Injury Following Cardiac Surgery in Neonates and Young Infants

Abstract

Objective: Acute kidney injury (AKI) following cardiac surgery is a serious complication with a reported incidence of 30% to 50%. This study sought to determine the prevalence and risk factors for AKI among neonates and young infants undergoing repair of cardiac defects at an institution using novel perioperative strategies. Methods: A retrospective analysis of 102 consecutive infants (<2 months) undergoing repair of cardiac defects on cardiopulmonary bypass formed the study group. Cardiac diagnoses were stratified according to the Society of Thoracic Surgeons Congenital Heart Surgery (STAT) mortality categories. The prevalence of AKI within 72 hours was defined according to the three-stage Acute Kidney Injury Network criteria. Novel bypass strategies to preserve renal function included maintenance of higher hematocrit and high flow rates on cardiopulmonary bypass despite systemic hypothermia, and avoidance of albumin and milrinone in the perioperative period. Results: Mean age was 24 ± 19 days. Eighteen patients were less than 7 days of age at the time of surgery. Patient distribution according to STAT categories was as follows: 1 (n = 21), 2 (n = 12), 3 (n = 22), 4 (n = 28), and 5 (n = 19). The incidence of stages 1, 2, and 3 AKI in the population was 8% (n = 9), 2% (n = 2), and 0% (n = 0), respectively. On multivariate analysis higher STAT category was the only significant risk factor for AKI. Conclusion: Current incidence of AKI following cardiac surgery in young infants at our institution is low. Novel perioperative strategies may have contributed to the low observed incidence of AKI in our patient population. Increased complexity of heart disease was a risk factor for AKI.