Spontaneous closure of atrial septal defects in premature vs. full-term neonates.

Our hypotheses were that the following factors influenced closure of atrial septal defects (ASDs) detected in neonates: estimated gestational age (EGA), the presence of a persistent ductus arteriosus (PDA), severity of pulmonary disease, gender, and the initial size of the ASD. Our population consisted of 82 newborns (38 premature and 44 term) who were found before the age of 1 month to have an ASD. Closure of ASDs was analyzed using both Kaplan-Meier survival analysis and the Cox proportional hazards model, each with the five covariates. The hazard ratio (or ratio of instantaneous closure rates) of term vs preterm infants was 3.60 (95% CI = 1.80-7.20), whereas the hazard ratio for infants with a PDA (compared to infants with no PDA) was 2.41 (95% CI = 1.28-4.54). Multivariate analysis showed that each of these terms (PDA and EGA) were independent predictors of ASD closure. The hazard ratio of ASD closure for each of four levels of pulmonary disease was 0.632 [95% CI = 0.453-0.881]. We conclude that the majority of neonatal ASDs will close, with EGA and PDA acting as important influences on closure.