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Pulmonary Atresia with Intact Ventricular Septum (IVS)

09/06/2023 Conditions

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Overview

Pulmonary atresia with intact ventricular septum is a congenital heart defect in which:

  • The pulmonary valve doesn’t form properly. The pulmonary valve allows blood to flow from the heart to the lungs to get oxygen. In this rare condition, instead of a normal pulmonary valve with three leaflets that open and close, a thickened, abnormal valve forms that does not open, blocking the blood flow to the lungs.
  • The right ventricle doesn’t fully develop. The right ventricle is the lower pumping chamber of the heart that is connected to the pulmonary valve and sends blood to the lungs. In this condition, there is lack of blood flow in the right ventricle that prevents it from developing normally. In some cases, the right ventricle at birth is big enough to pump blood to lungs. In other cases, the right ventricle may be too small, leaving the newborn with only one functioning ventricle.
  • The tricuspid valve doesn’t form normally. The tricuspid valve allows blood to flow from the right collecting chamber of the heart (right atrium) to the right ventricle.

The ventricular septum is the wall between the two pumping chambers of the heart. In pulmonary atresia with intact ventricular septum, this wall is intact.  

Babies born with pulmonary atresia don’t have enough oxygen in their blood to support the body’s needs. Treatment at birth is necessary for survival.

What happens in pulmonary atresia with intact ventricular septum?

The pulmonary valve is located between the right ventricle and the pulmonary artery, which carries blood to the lungs. Normally, when the right ventricle contracts, the pulmonary valve opens and oxygen-poor blood flows out into the pulmonary artery and on to the lungs for oxygen.

In a baby with pulmonary atresia, the pulmonary valve does not open. Oxygen-poor blood has to find an alternate route to reach the lungs.

Before birth, blood flowing into the right side of the heart can pass into the left side through a hole between the upper chambers of the heart called a patent foramen ovale. The oxygen-poor blood mixes with oxygen-rich blood before being pumped out to the body through the aorta. At birth, the foramen ovale usually closes but it may stay open in babies with pulmonary atresia.

Some of this mixed blood is able to reach the lungs through a temporary connection between the aorta and the pulmonary artery known as the ductus arteriosus. A newborn with pulmonary atresia depends on this connection to get the oxygen needed to survive. Following birth, the ductus arteriosus typically closes, however, a medication called prostaglandins (PGE) can be used to keep the ductus arteriosus open.

Cause and Prevalence

Pulmonary atresia with intact ventricular septum is a rare congenital heart defect. It occurs at a rate of less than one per 10,000 live births.

This defect occurs during the first eight weeks of pregnancy when the fetal heart fails to develop correctly. The cause is typically unknown.

Diagnosis

Pulmonary atresia with intact ventricular septum can be detected during pregnancy through a routine fetal echocardiogram (ultrasound of the fetal heart). A diagnosis during pregnancy enables your family and your healthcare team to plan ahead for the specialized treatment and cardiac expertise your baby will need at birth, optimizing outcomes. 

In some cases, the condition isn’t diagnosed until after the baby is born. Symptoms in a newborn may include:

  • Bluish tint to the skin, lips and nails (cyanosis) or pale skin, indicating a lack of oxygen in the blood
  • Difficulty breathing or rapid breathing
  • Fatigue
  • Clammy skin
  • Feeding problems

Specialized Prenatal Evaluation and Care

If pulmonary atresia with intact ventricular septum is detected during pregnancy, prompt referral to a fetal cardiac center is important for further evaluation and proper treatment planning.

At Texas Children’s Fetal Center, we arrange for you to visit with a team of specialists experienced in diagnosing and treating rare congenital heart defects, including maternal-fetal medicine physicians (OB/GYNs specializing in high-risk pregnancies), fetal and pediatric cardiologists, fetal imaging experts, congenital heart surgeons, neonatologists and genetic counselors.

Your baby will undergo additional testing and imaging to help us gain more information about the structure and function of the fetal heart.

Following a thorough evaluation and assessment, our specialists will meet with you about the results, provide treatment recommendations, and answer any questions your family has, to help you make the most informed decisions regarding your baby’s care and treatment.

Mother and baby will be closely monitored during pregnancy. Because the fetus receives oxygen through the placenta during pregnancy, treatment for pulmonary atresia with intact ventricular septum is not required until after birth.

Delivery

Because pulmonary atresia with intact ventricular septum is a life-threatening condition, delivery should take place at a center with the highest quality congenital heart program, ensuring the expertise and resources required to treat your baby at birth, including an advanced neonatal intensive care unit (NICU) and a cardiac intensive care unit (CICU). 

Delivery and postnatal care should be carefully planned and coordinated. Our Fetal Center team works closely with Texas Children’s Heart Center, seamlessly transitioning your baby’s care at delivery to this national leader in pediatric cardiology and heart surgery. Here, the heart specialists treating your newborn have been an integral part of the care team since before birth.

Following delivery at Texas Children’s Pavilion for Women, newborns with pulmonary atresia intact ventricular septum are transferred to Texas Children’s specialized CICU. 

Treatment After Birth

Treatment is required after birth to improve blood flow to the lungs and meet the baby’s oxygen needs. A medication to prevent the closure of the ductus arteriosus, called prostaglandins (PGE), is started as soon as the baby is born. This medication enables blood to continue to flow to the lungs for oxygen until a more permanent treatment strategy is determined.

Multiple factors are taken into consideration to decide the type and timing of surgical or catheter-based intervention in the newborn period. Some of these factors include the size of the right ventricle, the size of the tricuspid valve, any presence of coronary artery abnormalities or the presence of other associated heart defects.

Possible treatment strategies include:

  • Cardiac catheterization procedures may be used to open and expand the pulmonary valve (balloon valvuloplasty), enlarge the foramen ovale (balloon atrial septostomy), or insert a small metal tube to keep the ductus arteriosus open (stent placement).
  • Heart surgery to enable blood flow to reach the lungs. At birth, a surgery called a Blalock-Taussig shunt (BT shunt) is performed. A BT shunt is a small tube made out of synthetic material called Gore-Tex. It attaches a section of the aorta to the pulmonary artery, creating a sort of detour. This allows enough blood to pass through the lungs and pick up more oxygen. In cases where the right ventricle is too small, a series of two additional surgeries (three surgeries total) will be required during the first few years of life to enable the child’s heart to function with only one ventricle, also known as a single ventricle palliation.
  • Heart transplant, in severe cases where the baby’s heart is too damaged to repair or if additional high-risk heart defects are present

Postnatal Care Team

Depending on the severity of the condition, your baby’s postnatal care team may include:

Long-Term Care

Babies born with pulmonary atresia with intact ventricular septum require lifelong monitoring by cardiologists experienced in the treatment of congenital heart defects.

At Texas Children’s Heart Center, our pediatric cardiologists follow your child through adolescence, seamlessly transitioning their care at adulthood to our Adult Congenital Heart Disease (ACHD) program. 

Why Texas Children’s Fetal Center?

  • A single location for expert maternal, fetal and pediatric care. Texas Children’s Hospital offers mothers and babies the specialized care required for the diagnosis and treatment of congenital heart conditions all in one location, for highly coordinated care and treatment planning.
  • A skilled, experienced team with proven outcomes. We have a dedicated team of maternal-fetal medicine specialists, fetal imaging experts, fetal and pediatric cardiologists, congenital heart surgeons, neonatologists and others who work in concert to care for you and your baby every step of the way, using proven protocols we’ve developed over the years. With their combined expertise and unified approach, this team offers the best possible care for babies with pulmonary atresia with intact ventricular septum.
  • We care for your child’s cardiac needs at every stage of life, from fetus to adulthood. Our comprehensive approach starts with your first prenatal visit and continues through delivery, postnatal care, childhood and adulthood, thanks to one of the nation’s leading teams of fetal, pediatric and adult congenital heart specialists.

Texas Children’s – #1 in the Nation for Pediatric Cardiology and Heart Surgery

Our Fetal Cardiology Program is a collaboration between Texas Children’s Fetal Center and Texas Children’s Heart Center, ranked #1 in the nation for pediatric cardiology and heart surgery by U.S. News & World Report, with outcomes among the best in the nation.

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Research and Clinical Trials

Texas Children’s, together with our partner institution Baylor College of Medicine, constantly strives to seek new and better treatments for babies with congenital heart defects.

Learn more about our fetal cardiology research.

For additional information, please contact the Cardiovascular Clinical Research Core at 832-826-2064 or email sandrea@texaschildrens.org.

For more information or to schedule an appointment,

call Texas Children’s Fetal Center at 832-822-2229 or 1-877-FetalRx (338-2579) toll-free.

Our phones are answered 24/7. Immediate appointments are often available.