(774) Preoperative Iron Deficiency in Children With Single Ventricle or Cyanotic Congenital Heart Disease

Introduction: Children with single ventricle (SV) or cyanotic (C) congenital heart disease (CHD) have higher rates of iron deficiency (ID) due to cyanosis and compensatory polycythemia, concomitant heart failure, and feeding difficulties. Prospective data on the burden of ID in this population and associated outcomes are rare.

Methods: Patients (pts) aged 1-18 years with SV/C-CHD undergoing cardiac surgery at a single center were prospectively recruited from Nov 2022 to Jun 2023. ID was diagnosed as serum ferritin < 20ng/mL and/or transferrin saturation (TSAT) < 20% on pre-operative check. Demographic and clinical features were analyzed to assess for predictors of ID. Outcomes included intra- and post-operative (up to 7 days) red blood cell (RBC) transfusion and duration of post-operative hospitalization.

Results: Twenty-two pts were recruited for the study (funded by BCM CVRI Pilot Award), and 1 pt had clinically obtained pre-operative iron studies during the study period. Cohort demographics: median age 4.3yr (IQR 1.3 – 5.7yr), 70% male. Sixteen patients had SV-CHD and 7 pts with C-CHD underwent septation through index surgery. ID was present in 52% (12/23) with median ferritin 11 ng/mL (IQR 9-13 ng/mL) and median TSAT 19% (IQR 13-24%). Two pts with ID had microcytosis (sensitivity 19%). There was no difference between iron deficient and replete cohorts in terms of age, sex, socioeconomic status, tube feed dependence, body-mass index, renal/liver function tests, or inpatient status. Iron deficient and replete patients had similar hemoglobin (median 17g/dL, IQR 15 – 18 g/dL vs 17g/dL, IQR 16 – 19 g/dL, p=0.902). Iron deficient patients tended to have lower pre-operative oxygen saturations (median 81% vs 85%, p = 0.147), received more RBC transfusions post-operatively (p = 0.050), and tended to have a higher frequency of delayed sternal closure or sternal re-opening (33% vs 0%, p = 0.093). They also trended towards a longer ICU length of stay (median 6 days vs 3.5 days, p = 0.133).

Conclusions: This is the first prospective study on pre-operative ID in children with SV/C-CHD. In this single center study, we found ID in 52% of subjects. Children with pre-operative ID may have more post-operative morbidity with RBC transfusion and ICU length of stay. Larger studies are needed to confirm this signal.