Abstract 17071: Growth Asymmetry, Head Circumference and Neurodevelopmental Outcomes in Infants with Single Ventricles

Poor somatic growth is common in infants with single ventricle (SV) physiology and has been linked to increased morbidity and impaired neurodevelopment. Asymmetry in somatic growth, a potential brain-sparing adaptation, is important in predicting outcomes in premature and small for gestational age (SGA) infants. Objectives: To assess variability in growth asymmetry and its associations with neurodevelopment in infants with SV. Methods: We analyzed growth asymmetry (weight for age z-score (WAZ) minus head circumference for age z-score (HCAZ)), relative head growth (change in cm/change in kg), HCAZ, and change in HCAZ from baseline to pre-Glenn in subjects prospectively enrolled in the Pediatric Heart Network Infant Single Ventricle (ISV) trial. Associations between these indices and results of the Psychomotor Developmental Index (PDI) and Mental Developmental Index (MDI) of the Bayley Scales of Infant Development-II (BSID) at 14 months were assessed. Results: Of the 230 patients enrolled in ISV, complete biometric data and BSID results were available in 168 (73%). For this cohort, age at enrollment was 21±9 days, age at pre-Glenn was 167±52 days, gestational age was 38.3±1.4 weeks, and 71% were male. Growth asymmetry varied across the cohort at enrollment (0.43 ±1.02, range -2.85 to 4.84) and the pre-Glenn visit (-0.23 ±1.21, range -4.45 to 3.00) as did the relative head growth (2.40±0.86, range 0.50 to 8.00). BSID scores were not associated with indices of growth asymmetry. In univariate analysis, larger pre-Glenn HCAZ correlated with higher MDI (r=0.21, p=0.006) and PDI (r=0.38, p<0.001) and greater increase in HCAZ from enrollment to pre-Glenn was associated with higher PDI (r=0.15, p=0.049). In multivariable modeling adjusting for site, serious adverse events, stage 1 length of stay, and height at 14 months, pre-Glenn HCAZ was an independent predictor of PDI (p=0.03), but not MDI. For each one unit Z-score increase in pre-Glenn HCAZ, the predicted PDI score increased by 2.5 points. Conclusions: In infants with SV, BSID scores were associated with pre-Glenn HCAZ but not with the degree of asymmetric growth. Future studies should explore why asymmetric growth that seems important in premature and SGA infants appears less relevant in infants with SV.