Interrelationship between hemodynamics, brain volumes and outcome in Hypoplastic Left Heart Syndrome

BACKGROUND The long-term impact of altered hemodynamics after Stage II in children with hypoplastic left heart syndrome (HLHS) and hypoplastic left heart complex (HLHC) on cerebral growth and neurodevelopmental outcome is unknown. We aimed to investigate whether elevated central venous and atrial filling pressures before Fontan procedure may be associated with smaller brain volumes and poorer neurodevelopmental outcome after initial Hybrid procedure. METHODS In a two-center cohort study semi-automated segmentation of cerebral MRI scans was conducted in 25 children with HLHS/HLHC (25 Hybrid) before Fontan procedure (27.6 ± 4.3 months) and in 8 healthy controls (29.7 ± 9.5 months). Study patients were evaluated with the Bayley Scales of Infant and Toddler Development III (Bayley-III) and a neurological examination. Hemodynamic measures after Stage II were assessed with cardiac catheterization at two years of age before Fontan completion. Children with known genetic comorbidities were excluded. RESULTS In HLHS/HLHC patients, higher atrial filling pressures (6 ± 3 mmHg, range 2-14 mmHg) were correlated with reduced brain volumes and lower language composite score, while higher Glenn pressures (10 ± 3 mmHg, range 6-16 mmHg) were related to higher cerebrospinal fluid, reduced brain volumes and lower cognitive, language, and motoric composite scores in the Bayley-III. Compared to controls, white matter volumes were reduced, and cerebrospinal fluid volumes were increased in study patients. CONCLUSIONS These data suggest that altered cardiovascular hemodynamics after stage II influence brain growth and neurodevelopmental outcome in infants with HLHS/HLHC