Necrotizing enterocolitis in neonates with congenital heart disease: risk factors and outcomes

Necrotizing enterocolitis (NEC) is primarily a disease of the premature infant. Among children born at term, however, congenital heart disease may be an important predisposing factor for this condition. To determine risk factors for NEC in patients with congenital heart disease, we conducted a case-control study of neonates with cardiac disease admitted to the cardiac intensive care unit at our center during the 4-year period from January 1995 to December 1998.

Cardiac diagnosis and age at admission were analyzed for association with NEC among the 643-patient inception cohort. Demographic, preoperative, and operative variables were recorded retrospectively in 21 neonates with congenital heart disease who developed NEC and 70 control neonates matched by diagnosis and age at admission. Using parametric and nonparametric analysis, cases and controls were compared with respect to previously identified risk factors for NEC.

Among the entire cohort of 643 neonates with heart disease admitted to the cardiac intensive care unit, diagnoses of hypoplastic left heart syndrome (odds ratio [OR] = 3.8 [1.6-9.1]) and truncus arteriosus or aortopulmonary window (OR = 6.3 [1.7-23.6]) were independently associated with development of NEC by multivariable analysis. In the case-control analysis, earlier gestational age at birth (36.7 +/- 2. 7 weeks vs 38.1 +/- 2.3 weeks), prematurity (OR = 3.9 [1.2-12.5]), highest dose of prostaglandin >0.05 microg/kg/minute (OR = 3.9 [1. 2-12.5]), and episodes of low cardiac output (meeting specific laboratory criteria) or clinical shock (OR = 6.5 [1.8-23.5]) correlated with the development of NEC. Earlier gestational age and episodes of low output were the only factors that remained significantly associated with NEC by multivariable analysis. Although there was no difference in hospital mortality between patients with and without NEC, mean hospital stay was significantly longer in those who developed NEC (36 +/- 22 days vs 19 +/- 14 days).

The risk of NEC in neonates with congenital heart disease is substantial. Factors associated with an elevated risk of NEC in infants with heart disease include premature birth, hypoplastic left heart syndrome, truncus arteriosus, and episodes of poor systemic perfusion or shock. Heightened suspicion is warranted in newborns with these risk factors.