Jane Newburger, MD, MPH,
Executive Director, Cardiac Neurodevelopmental Program and Associate Cardiologist-in-Chief for Academic Affairs
What causes neurodevelopmental problems in children with congenital heart disease?
There are many causes. First, there can be genetic causes. The same genes that can cause a congenital heart defect can also cause the brain to form differently.
Second, brain growth might be influenced by the fetal environment, for example by fetal blood flow flows to the brain and supply of oxygen to the fetal brain. Our research has suggested that the rate of brain growth is somewhat slower in third-trimester fetuses with congenital heart disease than in those who don’t have congenital heart disease. On average, a term child with congenital heart disease has a brain that is about a month less mature than that of a baby born without heart disease or other problems.
Thirdly, the procedures that are needed to allow children with congenital heart disease to survive can themselves carry a risk of brain injury. In some cardiac operations, one needs to reduce blood flow to the body, and brain protection relies on cold temperatures with reduced blood flow to the brain. This can make the brain more vulnerable to fluxes in blood pressure and oxygen delivery in the period following the operation. We know that longer stay in the intensive care unit after surgery (related to how sick one is after surgery) can put a child at greater risk of neurodevelopmental problems. Recent studies suggest that some brain injury occurs even before a sick newborn is taken to the operating room for cardiac surgery.
Finally, the consequences of serious heart disease can be associated with neurodevelopment problems. For example, risk factors for neurodevelopmental delay include very low oxygen levels over years, poor nutrition and failure to thrive, episodes of cardiac arrest, brain infections, and other problems that are more common among cardiac children.
Who is at risk for neurodevelopmental disabilities?
Children who are at risk for neurodevelopmental problems are those with critical congenital heart disease who require a catheterization and/or surgery in the first year of life.
Within that group, the sickest children, particularly those who require open heart surgery in the first month of life, are most at risk. Those with cyanotic heart disease are at risk, even if they don’t have open heart surgery in the first year of life.
Risk factors also include prolonged stay in the intensive care unit, history of cardiac arrest, use of mechanical support (ECMO or a ventricular assist device), prematurity, or a history of seizures before or after surgery.
One of the most important risk factors for neurodevelopmental disability is the presence of particular types of genetic disorders. Infants and children with failure to thrive (poor gain of weight and height) should be carefully watched.
Finally, children with delayed milestones, unusual findings on neurologic examination or brain imaging warrant careful neurodevelopmental follow-up.
Why are neurodevelopmental problems a concern?
Neurodevelopmental disabilities can affect future employability, mental health and quality of life. For all those reasons, we want to initiate interventions that can improve neurodevelopmental outcomes as soon as possible.
Can neurodevelopmental problems be prevented?
We do everything that we can to prevent neurodevelopmental disabilities by careful treatment and monitoring before, during, and after surgery.
However, some risk factors for neurodevelopmental delays cannot be modified, such as problems that result from genetic abnormalities or fetal blood flow to the brain.
Sometimes the severity of the cardiac condition is so great that it affects the brain in ways that we try to diminish but cannot entirely prevent. We can, however, do everything possible to reduce the impact of these problems by early diagnosis and intervention.
What is the role of the Cardiac Neurodevelopmental Program at Boston Children's?
The role of the Cardiac Neurodevelopmental Program is to optimize the neurodevelopmental outcome of every child with heart disease. Some children have more serious challenges than others, but we aim to allow each child to reach his or her full potential.
What services does CNP provide?
Our cardiac neurodevelopmental team evaluates every child who has had heart surgery at Boston Children’s at an age younger than 1 year or who spends a very long period of time in the intensive care unit.
We also evaluate all children who go on to ECMO, or extracorporeal support, because their heart isn’t working well enough to sustain blood flow for a while.
If we find a child at risk, we initiate early intervention in babies and school interventions in older children, taking measures to protect the self-esteem of a school-aged child.
Fortunately, within the Cardiovascular Program, the Cardiac Neurodevelopmental Program coordinates specialists from different disciplines (neuropsychologists, neurologists, developmental pediatrics, geneticists, and cardiologists and cardiac surgeons), who work together to assess children and to put into place systems to provide the best kinds of therapy.
Our neuropsychologists often meet parents in the intensive care unit to show them how to stimulate and create the best environment for their child. They also assess which children should have early intervention after they go home, and they begin a dialogue with parents so that they’re aware of neurodevelopmental milestones and are empowered to work with their child to help them to meet those milestones to the best extent possible. We want each child to reach her full potential.
We also are able to evaluate children and adolescents with heart disease whose parents or pediatricians request neurodevelopmental evaluation. Parents, pediatricians or cardiologists of children with heart disease can contact the Cardiac Neurodevelopmental Program to request an evaluation.