Birth weight strongly predictive of survival in infants with congenital heart disease

Infants with congenital heart disease (CHD) born post-term and with the most body weight have the best chance of surviving for five years, while lighter, preterm babies have poorer chances, according to new research.

A study, led by Kate E. Best, with the Institute of Health & Society at Newcastle University in the United Kingdom, was published online July 21 in the Journal of the American Heart Association.

“Individuals with CHD often require complex life-saving surgeries in infancy and follow up for a lifetime,” the authors wrote. “Survival estimates are therefore important to understand prognosis and evaluate health and social care needs.”

This study aimed to estimate long-term survival of newborns with CHD, in contrast with previous studies of CHD mortality, which tended to report hazard ratios instead of survival estimates.

The research team analyzed data on 5,070 individuals, all born between 1985 and 2003, that had been reported to the Northern Congenital Abnormality Survey (NorCAS). The authors described NorCas as a high-quality, population-based register that gathers statistics on congenital anomalies among infants delivered to women who reside in the North of England.

Among the sample, 87.1 percent of children survived to age 5, 86.7 percent survived to age 10 years, and 85.2 percent survived to age 20 years.  Most of the children (53.7 percent) with isolated CHD were born at term and at an average birth weight. Five-year survival was highest (97.9 percent) among children born with high birth weight post-term. It was lowest (78.8 percent) among children born very preterm with a low birth weight.

They also found that survival increased with the passage of time. “For each year increase in year of birth, the risk of mortality decreased by 7 percent,” they wrote. They speculated that many factors contributed to this improvement of survival with time, including the development of surgical innovations such as the Fontan operation and the arterial switch operation, along with general advances in neonatal care.  

Information about the influence of gestational age and birth weight upon CHD survival will be valuable to parents of infants with congenital CHD. “For prenatal counseling, conditional survival estimates provide best- and worst-case scenarios, depending on final gestational age and birth weight,” the authors wrote. “For postnatal diagnoses, they can provide parents with more-accurate predictions based on their baby’s weight and gestational age.”