Neuro Disabilities and Congenital Heart Diseases

Congenital heart defects are one of the most common forms of birth defects in infants and children and nearly 8-12 of every 1000 are born with CHD. While, congenital heart defects ranks as the second most common cause of infant deaths (6-10 %) in high-income countries and 5th globally, it is emerging as one of the important causes of infant deaths in Low-and-Middle-Income Countries like India which are currently witnessing rapid demographic shifts. With improvements in quality of surgery and children heart treatment, the outlook of for most forms of CHD has substantially improved  in the recent decades. It is now estimated that 85% of children with CHD will survive into adulthood and adults with CHD are believed to outnumber the children in developed countries. With improved survival, the focus has now shifted towards long-term consequences and quality of life, of which brain development is one of the most important factors.

Disabilities from abnormal brain development, also known as neurodevelopmental delay are common, and arguably, the most damaging consequence of complicated childhood diseases including hole in heart by birth and congenital heart diseases. Previous studies have reported that children with heart defects who underwent cardiac surgery in infancy have more problems related to reasoning, learning, executive function, inattention and impulsive behaviour, language and social skills when compared with their normal counterparts. These studies also suggest that there is a distinctive pattern of abnormal brain development in areas of intelligence, academic achievement, language, visual disturbance, attention disorders, fine motor skills and psychosocial maladjustment. A prospective single-centre study from Amrita Institute of Medical Sciences identified evidence of delayed brain development in 15% of infants undergoing corrective heart surgery on 1-year follow-up.  As these children who had cardiac surgery during infancy reach adulthood, the persistent neurodevelopmental disabilities can impair their overall educational achievements, scope of employability, insurability, and quality of life.

The causes of neurodevelopmental delay in children with CHD are from a number of influences. Many such factors are innate and non-modifiable including presence of structural anomalies of the brain and associated genetic syndromes. Other factors pertinent to low-middle-income countries include late presentation due to delay in diagnosis, timely referral and lack of access to advanced children heart treatment, malnutrition and infections. Prolonged insult due to long-standing exposure to low oxygen levels (as in blue babies) or heart failure can further compromise the brain status. In addition, strategies adopted to protect the brain during the heart surgery also can play a role. It is possible that the prevalence and severity of neurodevelopmental sequelae in children after CHD surgery are likely to be more in the context of low and middle income countries in view of the above factors. The currently known risk factors explain only one third of the observed variation in neurodevelopmental outcome after cardiac surgery in infancy leaving us with an opportunity to explore further for other possible contributing factors.

It is critically important to identify probable modifiable factors related to neurodevelopmental outcomes after CHD surgery early. A multipronged approach that encompasses periodic surveillance of brain development, screening, evaluation, and re-evaluation throughout childhood may probably improve identification of significant deficits. This will also allow planning and implementation appropriate interventions to overcome the limitations. Such interventions have the potential to enhance later academic, behavioural, psychosocial, and adaptive functioning.

It is really important for parents of children with heart defects to understand that many of the serious congenital heart defects can have important long-term consequences that affect brain development. This is often very difficult for many parents to accept because of the stress that they go through when they take care of their children who already have a serious heart defect. However, it is imperative to carefully explain the need to monitor brain development so that if a deficit is identified early, suitable interventions can be undertaken to overcome the limitations.

Until recently, most parents were not being counselled appropriately about the prospect of their child having brain developmental issues after the heart defect has been corrected. There is also a common issue that relates to parents denying the fact that their child has issues relating to brain development. For this reason, it is important to formally test the child’s brain develop developmental status during follow up after heart surgery through structured processes under the supervision of a suitable trained neuro-developmental, expert.

The pediatric cardiology department of Amrita Institute of Medical Sciences, Cochin is now conducting a nationwide study in multiple Indian centres to formally test the impact of cardiac surgery on childhood neurodevelopment.  The results of the study will inform other pediatric cardiac professionals in the country about the extent of problem and the need for formal testing of children with heart disease before and after cardiac surgery.

Contributed by Dr R Krishna Kumar MD DM FAHA,
Clinical Professor and Head, Pediatric Cardiology,
Amrita Institute of Medical Sciences and Research Centre,
Cochin, 682041, Kerala, India
Phone +91-4842853570
E-mail: [email protected]