More often now, than a generation ago, babies born with CHD are being diagnosed prenatally. This week, Dr. Sheetal Patel, from Lurie Children’s Hospital of Chicago and Assistant Professor of Pediatrics, Northwestern University Feinberg School of Medicine, explains the role prenatal echocardiography plays in diagnosing CHD and the benefit of that early diagnosis.
Congenital Heart defects (CHDs) are among the most common birth defects, affecting 1 out of every 110 babies born. Each year nearly 40,000 babies are born in the United States with CHD, ranging from simple lesions that may not need any interventions to complex CHDs that can be fatal if appropriate treatment is not provided soon after birth. Research shows that prenatal diagnosis and early detection of these complex CHDs is associated with improved surgical outcomes. With improvement in diagnostic technology with Fetal echocardiogram today, about 70% of complex CHDs are detected prenatally. Goals for detection are targeted at 100%, and we are aiming to reach there with improved awareness and better screening techniques.
A fetal echocardiogram is an ultrasound test performed during pregnancy to evaluate the heart of the unborn child and can be performed as early as 18 weeks gestation. Diagnostic accuracy for detecting complex CHD with a fetal echocardiogram is as high as 95%. It is a non-invasive procedure performed with an ultrasound probe placed over mother’s belly. Generally, the pain or discomfort that results from the probe pressure on the mother is minimal. It involves detailed evaluation of baby’s cardiac structures including cardiac chambers, valves and major blood vessels. It also evaluates fetal heart rate and rhythm. This test can detect CHDs such as missing heart chambers (such as hypoplastic left heart syndrome, hypoplastic right heart syndrome, and many other variations), abnormal great arteries (such as transposition of the great arteries, truncus arteriosus, interrupted aortic arch, etc), abnormal cardiac valves (such as atrioventricular septal defect, pulmonary valve atresia), or large hole between cardiac chambers (such as a large ventricular septal defect). There are limitations of fetal echocardiography that it may not detect minor cardiac valve abnormalities, small holes between cardiac chambers or coarctation of aorta that develops after birth.
Early detection of CHD before baby’s birth has many advantages.
Prenatal diagnosis of CHD allows for necessary preparation to provide highly specialized care that the baby will require soon after the birth and prevents the hemodynamic compromise that can result if this CHD was undetected. This preparation involves coordinated care by multiple teams with expertise in pediatric cardiology, neonatology, pediatric cardiac intensive care and pediatric cardiovascular surgery. In addition, social worker, child life specialists, and palliative care teams may be available to help parents cope with the diagnosis and treatment. An important aspect of early detection is to provide expectant parents the opportunity to have detailed counselling. This counselling helps parents to better understand their unborn child’s heart condition and interventions that might be needed. This aids parents in their research to choose a center of excellence for their baby’s care. The goal of this prenatal counselling is for parents to be armed with knowledge, process the information over time, and maximize the family’s preparedness for the journey and transition to a birth of their new baby. Research shows that those mothers who knew about their baby’s heart condition prior to the birth were less anxious once the baby was born as compared to mothers who found out about the defect after baby was born.
There are some standard indications for fetal echocardiography during pregnancy.
Not every expectant mother needs to have a fetal echocardiogram. However, if the risk of having CHD in the unborn child is expected to be higher than general populations, a fetal echocardiogram is indicated. These risk factors include having a prior child with congenital heart defects, maternal diabetes, maternal infections during pregnancy known to affect baby’s heart, etc. Mother should discuss with her obstetrician if a fetal echocardiogram is indicated based on the family history and her own medical history. If indicated, a fetal echocardiogram should be arranged to be performed between 20 to 24 weeks gestation which is an ideal time for accurate diagnosis of CHD. Other indications for fetal echocardiogram include abnormal findings on obstetrical screening test such as increased nuchal thickness, abnormal cardiac images during the level II anatomy scan, chromosomal abnormalities (such as trisomy 21, trisomy 18, trisomy 13, Turner syndrome, etc) detected during the prenatal genetic testing, or other organ malformations noted during the anatomy scan. These abnormal screening tests indicate higher risk of CHD in the fetus and therefore, a fetal echocardiogram is indicated.
What happens after a fetal echocardiogram detects CHD in fetus?
A pediatric cardiologist performing the fetal echocardiogram will discuss the findings of CHD in details with the expectant parents. Tailoring the counselling to the parent’s needs over time is critical as parents can be very overwhelmed during the initial hearing of a diagnosis of CHD. Counselling should include discussion about implications of this CHD on baby during the pregnancy, what support and care this baby would need soon after the birth, what interventions, procedures and surgeries would be necessary during neonatal period, and what other procedures or surgeries would be needed later in life and what is expected overall prognosis with this CHD. The goal of this counselling process is to provide information to parents that would help them with their decision making to choose their options. The options are described in details that include preparing them for this journey to have child with CHD, palliative care or other family planning options.
Each Fetal Cardiac Program have unique set up to provide this detailed counselling. At Lurie Children’s Hospital; these services are provided through our fetal cardiac program at The Chicago Institute for Fetal Health. Following the initial consultation, parents have a “Comprehensive Fetal Cardiac Consultation” which includes a follow up fetal echocardiogram to assess the evolution of the CHD (if any), consultation with a fetal cardiology team composed of a pediatric cardiologist, neonatologist, cardiac intensivist, cardiovascular surgeon, social work, and other specific team pertinent to the diagnosis. For example, a consultation for prenatal diagnosis of HLHS would include a specialist for “Single ventricle Program”. Parents may also choose to meet with “cardiac neurodevelopment team” and “Child life Specialist” if they are interested in learning more about these important aspects of their child’s quality of life in future. The number of partners at the table during this meeting can seem overwhelming to some parents and modifications are made to this process to meet each family’s needs.
Our goal as a comprehensive fetal cardiology team is to arm families with information, answer questions, form a united care team to provide cohesive CHD care pre and post-natally, and optimize the chances for the most successful outcome and quality of life throughout a lifetime.
Dr. Sheetal Patel is Associate Director of Fetal Cardiac Program at Ann & Robert H Lurie Children’s Hospital of Chicago and Assistant Professor of Pediatrics at Northwestern University Feinberg School of
Medicine. Her clinical interest lies in fetal, neonatal and pediatric cardiology. She is passionate about prenatal diagnosis of congenital heart defects. Her research interests are in evaluating outcomes in
congenital heart defects, with special focus on single ventricle heart defect and Fontan palliation.