To determine the prevalence of iron deficiency and iron deficiency anemia and their association with adverse outcomes in children undergoing cardiac surgery with cardiopulmonary bypass.

Retrospective review.

Single-center, academic quaternary children’s hospital.

Eight hundred eighty-six cardiac surgery patients aged 0 to 18 years at the authors’ institution between 2019 and 2023.

None.

Patients were screened for iron deficiency and anemia using ferritin, hemoglobin, and reticulocyte hemoglobin equivalent levels. Perioperative outcomes were measured and analyzed using multiple logistic and linear regression adjusting for both surgical complexity and cardiopulmonary bypass times. Patients with iron deficiency received greater perioperative red blood cell transfusion volumes (31.2 ± 36.8 mL/kg v 21.9 ± 29 mL/kg, p < 0.001) and had an increased incidence of postoperative acute kidney injury (30.2% v 20.8%, p = 0.002) than those without iron deficiency. Patients with iron deficiency anemia received larger red blood cell transfusion volumes (33 ± 33.7 mL/kg v 22 ± 29 mL/kg, p = 0.002) and were more likely to develop acute kidney injury (37% v 21%, p = 0.006) compared with those with normal iron and hemoglobin levels. These findings persisted after adjusting for age, weight, surgical complexity, and cardiopulmonary bypass time.

Iron deficiency is common in children undergoing cardiac surgery and is associated with an increased risk of adverse outcomes. Future prospective studies aimed at understanding and managing iron deficiency in patients with congenital heart disease are urgently needed.