Necrotizing enterocolitis in infants with congenital heart disease: the role of red blood cell transfusions.

Necrotizing enterocolitis (NEC) is a rare but catastrophic complication that may occur in newborns with congenital heart disease (CHD). In the preterm population, transfusion of red blood cells (RBCs) and use of RBCs with longer storage time have been independently associated with the development of NEC. To date, it is not known whether similar associations exist for the term newborn with CHD. This retrospective study identified the incidence of NEC among 1,551 newborns admitted to the authors' cardiac intensive care unit between 7 January 2002 and 7 January 2010. The study was limited to term newborns (>36 weeks gestation). To understand the impact of RBC transfusions on the development of NEC, a nested 2:1 matched case-control analysis was undertaken to compare RBC transfusion patterns between an age-matched group and a cardiac lesion-matched control group. In the study population, NEC developed in 45 term infants during the postoperative period. Of these 45 infants, 30 (66.7%) had single-ventricle heart defects, whereas 22 (48.8%) required surgery for aortic arch obstruction. The median patient age at NEC diagnosis was 21 days. The RBC transfusion rate was higher among the patients who experienced NEC (0.21/day) than among the control subjects (0.10/day) (p = 0.048). A multivariate analysis indicated that onset of NEC was associated with a greater number of RBC transfusions (odds ratio [OR] 1.83; 95% confidence interval [CI] 1.07-7.47; p = 0.045). The duration of RBC storage was not significantly longer in the NEC group (9 days) than in the control cohort (7 days) (p = 0.16). Increased exposure to RBC transfusions is associated with the development of NEC in term infants with CHD. Longer storage of RBCs does not appear to increase this risk. Although causality cannot be confirmed, these data prompt a careful review of RBC transfusion practices with this population.