Neurodevelopmental outcomes of congenital heart disease

William Mahle
Director of Clinical Research at Children’s Healthcare of Atlanta
Associate Professor of Pediatrics, Emory University School of Medicine
Atlanta, USA

Prior to the early 1980s, it was uncommon for children with complex congenital cardiac malformations to survive into later childhood. Since that time there has been a dramatic fall in surgical mortality, with complex repairs taking place at increasingly younger ages. At many large centers, palliative surgery followed by later repair was replaced by primary repair in infancy, and staged reconstructive surgery for various forms of functionally univentricular heart, including those with hypoplastic left heart syndrome, was improving with steadily falling surgical mortality rates. As a result, the last decade has seen an increasing number of children entering primary and secondary schooling. Research into their academic and behavioral outcomes has revealed some sobering realizations about the outcomes in these surgical survivors.
　As a group, patients with complex congenital cardiac malformations have a significantly higher incidence of academic difficulties, behavioral abnormalities, fine and gross motor delays, problems with visual-motor integration and executive planning, speech delays, inattention, and hyperactivity. Injury to the central nervous system in infants with congenital cardiac disease is characterized by abnormalities of tone, feeding difficulties, delays in major motor milestones, and abnormalities in speech. As these children get older, the need for special services in school is significantly increased compared to the general population. As children progress through school, low academic achievement scores, learning disabilities, behavioral problems and attention deficit/hyperactivity disorder may result in academic failure, poor classroom and social skills, low self-esteem, behavioral disinhibition, and ultimate delinquency.
　Depending upon a number of factors, including the underlying congenital lesion and the associated surgical management, genetic contributions, additional perinatal events such as profound hypoxia–ischemia from a delayed diagnosis, or postoperative events such as low cardiac output syndrome, the incidence of abnormalities may range from infrequent to ubiquitous. For example, in cohort studies of children with transposition, a small fraction may have severe developmental impairment, perhaps one-half are normal in all respects, and nearly one-half will have a combination of speech, motor, behavior, or learning issues. The percentage of children with more “significant” cardiac disease, for example, totally anomalous pulmonary venous return with obstruction, hypoplastic left heart syndrome, or interruption of the aortic arch, who are developmentally “normal” is significantly decreased, with perhaps only one-third of those tested having no dysfunction in any domain. While most of these abnormalities are relatively mild, and may only be determined by formal testing, they result in a so-called “high-prevalence, low-severity” developmental “signature”.
　Importantly, the combined outcomes of developmental delay, academic difficulties, and behavioral abnormalities, in combination, represents the single most common morbidity affecting the quality of life in school-age survivors with congenital cardiac disease. This complication is more common than late mortality, severe exercise impairment, unplanned reoperations, bacterial endocarditis, or significant arrhythmias. The later implications of these findings through adulthood are uncertain, and must continue to be a robust area of research.