Incidence, Risk Factors, and Outcomes of Hyperferritinemia after Pediatric Cardiac Surgery with Cardiopulmonary Bypass: A Retrospective Study

Objective: Serum ferritin has been identified as a prognostic marker in patients with a variety of diseases. In the present study we aim to determine the prevalence of risk factors and outcomes for hyperferritinemia in children undergoing cardiac surgery with cardiopulmonary bypass for congenital heart defects. Methods: The serum ferritin levels of 457 children between the ages of twenty-eight days and three years undergoing cardiopulmonary bypass surgery between June 1, 2017 and June 1, 2018 were analyzed. The prevalence of early postoperative hyperferritinemia was investigated; hyperferritinemia was defined as a ferritin level >= 250 ng/ml. Multivariable regression models including candidate risk factors were constructed to determine the independent predictors of serum ferritin levels post-bypass, analyzed as continuous variables (linear regression) and categorized variables (logistic regression). Multivariable logistic regression was applied to assess the relationship between postoperative hyperferritinemia and a composite of in-hospital mortality, acute kidney injury, extracorporeal life support, prolonged postoperative hospital length of stay and prolonged postoperative mechanical ventilation. Results: Of the 457 included patients, frequency of post-cardiopulmonary bypass hyperferritinemia was 59/457 (10.9%). In multivariate logistic analyses, age [odds ratio (OR) 0.776/90 days], maximum cardiopulmonary bypass flow [OR 1.031/(1 ml/kg)], cardiopulmonary bypass duration (OR 1.095/10 mins) and preoperative hemoglobin [OR 1.207/(10 g/L)] were significantly associated with early postoperative day 1 hyperferritinemia. After risk adjustment, hyperferritinemia was independently associated with the composite outcome (OR 6.373; 95%CI 2.863 similar to 14.184, p < 0.001), and improved model discrimination, (AUC 0.868; 95%CI 0.821 similar to 0.916) compared with basic clinical prediction alone (AUC 0.840; 95%CI, 0.790 similar to 0.890; Delta AUC = 0.0279, p = 0.0218). Conclusion: In this study, we found early postoperative hyperferritinemia was relatively common in pediatric patients after cardiopulmonary bypass. The occurrence of hyperferritinemia may help identify a population at risk of unfavorable in-hospital outcome.