This chapter provides an overview of the developmental outcome in the child or young adult who has undergone a Fontan procedure as long-term palliation for a functionally single ventricle CHD. Brain abnormalities and neurocognitive impairment are common in people living with a Fontan circulation and can be more prominent in adults. Possible mechanisms include prenatal (foetal brain dysmaturation, developmental genetic changes, altered cerebral blood flow in utero) and postnatal factors (challenges associated with the Fontan surgical pathway, prolonged cyanosis during the first years of life, the impact of multiple procedures, and prolonged and numerous hospital stays). Magnetic resonance imaging studies have reported an incidence of structural brain injuries up to 90% in the adolescent and young adult cohort of Fontan patients. These findings are associated with various cognitive symptoms, including memory, attentional, and behavioural impairments (i.e. intellectual deficits, learning difficulties, pragmatic language, social interaction, visuospatial, motor, and executive function deficits) that persist into adulthood. More recently, some authors have shown that global brain volumes are significantly smaller in adolescents and adults with a Fontan circulation and that lower volumes are associated with lower oxygen saturations and neurocognitive functioning. For these reasons, understanding if there are modifiable factors that can contribute to brain injury is of paramount importance to optimize neurocognitive function after the Fontan procedure. We propose to integrate routine formalized neurocognitive assessment into cardiac care for children, adolescents and adults with a Fontan circulation, with appropriate care pathways and support networks.
