Risk Factors and Outcome of Acute Kidney Injury after Congenital Heart Surgery: A Prospective Observational Study

Backgrounds and Aims: Acute kidney injury (AKI) is a frequent event after congenital heart surgery with increased mortality and morbidity. We investigated frequency, risk factors, and associated morbidity and mortality of AKI after pediatric cardiac surgery at a single institution. Methods: Children undergoing congenital heart surgery from March 2013 to February 2016 were assessed for development of AKI based on modified pediatric Risk, Injury, Failure, Loss, and End-stage renal disease criteria. They were also investigated for predictive risk factors, associated mortality, and morbidity including duration of mechanical ventilation, Intensive Care Unit (ICU), and hospital length of stay. Results: Five hundred and nineteen patients were recruited during the study period including 259 (49.9%) males and 260 (50.1%) females. AKI was seen in 150 (28.9%) patients including 101 (67.3%), 42 (28%), and 7 (4.7%) cases with risk, injury, and failure stages, respectively. Patients with AKI had longer ventilation time (P = 0.002), ICU (P = 0.05), and hospital (P = 0.56) stay. Mortality was seen in 31 (2.7%) and 44 (11.9%) patients with and without AKI, respectively (P = 0.01). After multivariable logistic regression, there was an association between AKI and preoperative abnormal levels of creatinine (adjusted odds ratio [aOR] = 0.47, 95% confidence interval [CI] 0.22–1.01; P = 0.05), presence of cyanotic heart disease (aOR = 1.97, 95% CI = 1.15–3.2; P = 0.01), duration of surgery (aOR = 1.05/10 min, 95% CI = 1.01–1.08; P = 0.007), and elevated lactate level (aOR = 1.14, 95% CI = 1.03–1.3; P = 0.01). Conclusion: The presence of cyanotic heart disease, duration of surgery, elevated postoperative lactate level, and likely preoperative creatinine level were independent risk factors for the development of AKI after congenital heart surgery.