BackgroundFew studies have described the neuropsychological outcomes and frequency of structural brain or genetic abnormalities in adolescents with single ventricle who underwent the Fontan procedure.Methods and ResultsIn a cross‐sectional, single‐center study, we enrolled 156 subjects with single ventricle, mean age 14.5±2.9 years, who had undergone the Fontan procedure. Scores in the entire cohort on a standard battery of neuropsychological tests were compared with those of normative populations or to those of a group of 111 locally recruited healthy adolescents. They also underwent brain magnetic resonance imaging and were evaluated by a clinical geneticist. Genetic abnormalities were definite in 16 subjects (10%) and possible in 49 subjects (31%). Mean Full‐Scale IQ was 91.6±16.8, mean Reading Composite score was 91.9±17.2, and mean Mathematics Composite score was 92.0±22.9, each significantly lower than the population means of 100±15. Mean scores on other neuropsychological tests were similarly lower than population norms. In multivariable models, risk factors for worse neuropsychological outcomes were longer total support and circulatory arrest duration at first operation, presence of a genetic abnormality, more operations and operative complications, more catheterization complications, and seizure history. The frequency of any abnormality on magnetic resonance imaging was 11 times higher among Fontan adolescents than referents (66% versus 6%); 19 (13%) patients had evidence of a stroke, previously undiagnosed in 7 patients (40%).ConclusionsThe neuropsychological deficits and high frequencies of structural brain abnormalities in adolescents who underwent the Fontan procedure highlight the need for research on interventions to improve the long‐term outcomes in this high‐risk group.

Objective To describe the relationship between altered white matter microstructure and neurodevelopment in children with d-transposition of the great arteries (d-TGA). Study design We report correlations between regional white matter microstructure as measured by fractional anisotropy (FA) and cognitive outcome in a homogeneous group of adolescents with d-TGA. Subjects with d-TGA (n=49) and controls (n=29) underwent diffusion tensor imaging and neurocognitive testing. In the group with d-TGA, we correlated neurocognitive scores with FA in 14 composite regions of interest in which subjects with d-TGA had lower FA than controls. Results Among the patients with d-TGA, mathematics achievement correlated with left parietal FA (r=0.39, p=0.006), inattention/hyperactivity symptoms with right precentral FA (r=−0.39, p=0.006) and left parietal FA (r=−0.30, p=0.04), executive function with right precentral FA (r=−0.30, p=0.04), and visual-spatial skills with right frontal FA(r=0.30, p=0.04). We also found an unanticipated correlation between memory and right posterior limb of the internal capsule FA (r=0.29, p=0.047). Conclusion Within the group with d-TGA, regions of reduced white matter microstructure are associated with cognitive performance in a pattern similar to healthy adolescents and adults. Diminished white matter microstructure may contribute to cognitive compromise in adolescents who underwent open-heart surgery in infancy.