Incidence and risk factors for acute kidney injury associated to surgery for congenital heart disease

Background: Acute kidney injury (AKI) occurs frequently after cardiac surgery for congenital heart disease and it has a great impact on patient´s prognosis. Objective: The aims of this study were to determine the incidence and risk factors for AKI in children undergoing cardiac surgery and its impact on mortality, duration of mechanical ventilation, ICU and total hospital length of stay. Methods: This was a historical cohort study of children 0-18 years of age who underwent cardiac surgery between 2012 and 2014. We used the Risk Adjustment for Congenital Heart Surgery-1 (RACHS) scale to evaluate risk of the surgery. AKI was defined in accordance to the Acute Kidney Injury Network (AKIN) criteria. Results: A total of 485 patients were included. AKI occurred in 89 (18.3%) patients during the study period. Risk factors for AKI were age < 2 years, cardiopulmonary bypass (CPB) time > 120 min and RACHS score > 3. AKI increased the mortality risk (OR: 5.82, 95% CI: 2.24-15.10) and the time in mechanical ventilation and ICU stay from 1 to 5 days and 6 to 12 days, respectively. Conclusions: Risk factors for AKI are younger age, higher RACHS score, and time of CPB greater than 120 minutes. AKI increases mortality, days on MV and ICU stay. In the present study AKIN scale allowed us to classify the severity of AKI and it correlated with prognosis after cardiac surgery.