Abstract 13228: The Effect of Gestational Age and Size at Birth on Brain Injury and Developmental Outcomes in Congenital Heart Disease

Background:Early delivery and size at birth are known to be independent risk factors for neurodevelopmental (ND) impairments among patients with complex congenital heart disease (CHD). The aim of this study was to explore the interaction between gestational age (GA) and size at birth and their relationship with postnatal brain injury and developmental outcomes among patients with CHD.Methods:This was an analysis of a prospective study of neonates with d-transposition of the great arteries (TGA) or single ventricle physiology (SVP) that underwent pre- and post-operative brain MRIs and ND testing. The primary outcome was white matter injury (WMI) on the pre-operative MRI. Secondary outcomes included fractional anisotropy (FA) in white matter as a measure of microstructural development and psychomotor (PDI) and mental development indices (MDI) on the Bayley scale of infant development-II at 30 months. Primary predictors included z-scores for birth weight (WZ), length (LZ) and head circumference (HCZ) and GA at birth categorized as early term (37-38 weeks) or term (>39 weeks). Growth asymmetry was measured by the difference in WZ and HCZ and categorized as symmetric, asymmetric with a small head relative to body and asymmetric with a large head relative to body.Results:187 subjects (112- TGA; 75- SVP) were analyzed of which 74 were early term and 113 were term. There was no relationship between growth parameters with WMI or white matter FA on the pre-operative brain MRI. WZ, LZ and HCZ were not associated with MDI or PDI at 30 months of age in either GA category. However, there was a significant association between growth asymmetry and MDI after adjusting for hospital length of stay and GA at birth. Compared with symmetric infants, SVP infants with a small head relative to body had significantly lower MDI scores (?= -38, 95%CI: -65, -11; p= 0.01) while there was a trend in TGA infants (?= -8, 95%CI: -19, 4; p= 0.1)Conclusions:Size at birth is not associated with early measures of brain injury or development. However, asymmetric size at birth regardless of GA is associated with worse cognitive outcomes at 30 months of age, particularly for SVP patients. These findings suggest that ND impairment in CHD is multi-factorial with early origins.