Pulmonary Atresia

Pulmonary atresia (PA) is a rare congenital abnormality of heart development where the pulmonary valve that controls blood flow from the right side of the heart to the lungs doesn’t form (atresia).

As an international referral center for children with complex congenital heart disease, the University of Michigan C.S. Mott Children's Hospital Congenital Heart Center is one of the largest and best pediatric heart programs in the United States. University of Michigan pediatric heart specialists offer state-of-the-art treatment and management of congenital heart conditions, including a comprehensive range of support services and long-term follow up care for children and their families.

What Is Pulmonary Atresia with Ventricular Septal Defect?

Pulmonary atresia with ventricular septal defect (PA-VSD) is a form of PA in which there is also a large hole in the septum, which is the common wall between the heart’s two pumping chambers (or ventricles). The VSD provides a pathway for de-oxygenated blood to get from right to left ventricle where it is pumped to the body and also to the lungs for oxygenation.

PA-VSD is often considered the most severe form of tetralogy of Fallot (TOF).

 In PA-VSD, there is a wide spectrum of severity depending on the degree of pulmonary artery development and the source of blood flow to the lungs. In the mildest form of PA-VSD, the pulmonary valve may not have an opening, but the main pulmonary artery and branch pulmonary arteries are relatively well-developed and of adequate size. In this subset of patients, blood flow from the right side of the heart to the lungs is through the VSD to the left side of the heart, across the aortic valve, and through a normal connection between the aorta and the pulmonary arteries (patent ductus arteriosus) that remains open in many newborns for a few hours to several days.

On the opposite end of the spectrum are infants born with PA-VSD and grossly underdeveloped or absent main and branch pulmonary arteries. In the majority of these children, there is no patent ductus arteriosus, and pulmonary blood flow is usually supplied by a number of abnormal collateral blood vessels originating from the ascending and descending thoracic aorta. Unlike native pulmonary arteries, these aortopulmonary collateral arteries (APCs) do not grow normally and often get severely narrowed over time.

PA-VSD represents approximately 2-3 percent of all cases of congenital heart disease (CHD), is slightly more common in males than females, and occurs in nearly one infant for every 10,000 births. The cause of PA-VSD is unknown but genetic factors likely contribute with an increased risk of occurrence in siblings and offspring of adults with PA-VSD and TOF. Associated genetic syndromes include trisomy 21 (Down syndrome), VATER syndrome, Alagille syndrome, and DiGeorge syndrome.

Symptoms of PA-VSD

The clinical symptoms of PA-VSD include bluish skin discoloration (cyanosis) particularly around the lips, eyes, and nail beds; difficulty with feeding; and failure to thrive (poor weight gain).

Diagnosing PA-VSD

The diagnosis of PA-VSD is often suspected by a combination of physical exam findings, pulse oximetry, chest X-ray, and electrocardiography. Ultimately, echocardiography (an ultrasound of the heart) confirms the diagnosis, and helps to detail the specific anatomy for planned surgical intervention. In many cases, cardiac catheterization with angiography and/or cardiac magnetic resonance imaging is also necessary to further identify the various sources of pulmonary blood flow and the size and distribution of the native pulmonary arteries, if present.

Treatment of PA-VSD

Infants with pulmonary blood flow that is dependent on a patent ductus arteriosus require prostaglandin infusion in the neonatal period to keep the ductus open. Once stable on prostaglandins, these infants will require a surgical or catheter-based intervention to provide a stable source of pulmonary blood flow prior to discontinuing prostaglandins. Rarely, an infant with membranous pulmonary atresia may be a candidate for primary surgical correction in the newborn period. More frequently, surgery will be scheduled after the child has had some time to grow.

For infants with PA-VSD and multiple abnormal collateral arteries, prostaglandins are probably not helpful. Depending on the specific anatomy and the arterial oxygen saturation (reflecting the amount of pulmonary blood flow), treatment options may include surgical repair with a shunt to augment pulmonary blood flow, or no intervention until the patient is older.

Ultimately, the goal of any staged surgical repair is to establish flow from the right side of the heart across to the native pulmonary arteries, and ultimately closure of the VSD. In some patients with absent native pulmonary arteries or severe pulmonary artery hypoplasia, this may never be an achievable goal. In others, rehabilitation of the pulmonary arteries may be possible over time, and one may ultimately achieve a satisfactory surgical result.

Life with PA-VSD

Unlike the majority of patients with TOF who do well following surgical correction, the outcomes for patients with PA-VSD is extremely variable. Those who are able to have a complete repair may ultimately do well, although recurrent procedures are much more common for PA-VSD patients than those with a repaired TOF. Unfortunately, many patients will not be candidates for complete repair, and will require multiple palliative procedures over their lifetime to provide sufficient pulmonary blood flow and oxygenation to allow for normal growth and development.

 The frequent association of PA-VSD with other genetic diseases also places these children at increased risk for neurodevelopmental abnormalities unrelated to their heart. Continued evaluation for these children is highly recommended to ensure early identification of delays. The C.S. Mott Children’s Hospital Congenital Heart Center Neurodevelopmental Follow-Up Program offers a complete developmental assessment and referral program to ensure early intervention and support for children experiencing neurodevelopmental delays to provide a solid foundation for later learning and future development.

Why Choose C.S. Mott Children’s Hospital for PA-VSD Care

The University of Michigan Congenital Heart Center at C.S. Mott Children’s Hospital has been a national and international leader in surgical and catheter-based interventions for pulmonary atresia and pulmonary atresia with ventricular septal defect for more than four decades.

We design personalized treatment plans for each patient, created through tight collaboration between our pediatric cardiac surgeons and our interventional cardiology team. We also continue to critically examine our results to assess if our individualized, staged approach results in the best outcomes for different subgroups of patients with PA-VSD compared to our peer institutions across the country.

We are uniquely positioned to care for PA-VSD patients from infancy through adulthood, as a children’s and women’s hospital directly attached to an adjacent adult cardiovascular center. In addition, through our innovative research and participation in multi-institutional clinical studies, we are on the forefront of clinical quality improvement initiatives and novel approaches to safely caring for patients with PA-VSD.

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