Effects of Gestational Age on Early Survivability in Neonates With Hypoplastic Left Heart Syndrome

Prematurity increases pre- and postoperative mortality in children with congenital heart disease. There are no large, multicentered, studies that have evaluated this relation specifically in neonates with hypoplastic left heart syndrome (HLHS). We sought to determine the impact of gestational age (GA) on survival to Stage 1 palliation surgery and hospital discharge in infants with HLHS. We reviewed data from 1,913 neonates with HLHS born at or transferred to a Vermont Oxford Network expanded member hospital in the United States from 2009 to 2014. Demographic, diagnostic, and surgical codes, and outcome data within the Vermont Oxford Network database were used to determine the effect of GA and birth weight on survival to Stage 1 palliation surgery and hospital discharge. Risk models were developed controlling for common confounders to determine the relative risk of GA on the observed outcomes. These data demonstrate that, when compared with 39-week infants, those born at earlier GA were less likely to survive until surgery; <34 weeks adjusted risk ratio (ARR) for survival: 0.47 (95% confidence interval 0.37 to 0.60), 34 to 35 weeks ARR 0.73 (0.62 to 0.87), and 36 to 37 weeks ARR 0.88 (0.83 to 0.94). Higher GA also positively correlated with survival to hospital discharge, although there was no difference in 34 to 35-week infants and 36 to 37-week infants. In conclusion, these data show that GA was an independent risk factor for survival to Stage 1 palliation surgery and survival to hospital discharge. However, there is no significant difference in survival to hospital discharge between infants born in 34 to 37 weeks gestation.