Pulmonary Atresia: From Fetal Diagnosis to Adult Care

Pulmonary atresia is a congenital heart defect in which the pulmonary valve never forms properly, blocking blood flow from the heart to the lungs. Without treatment, it is fatal in the newborn period because the only route for blood to reach the lungs is through a temporary vessel called the ductus arteriosus, which naturally closes within days of birth. The condition comes in two distinct forms that differ sharply in anatomy, surgical strategy, and long-term outlook, and advances over the past several decades have turned what was once uniformly lethal into a condition most children survive into adulthood.

Two Distinct Conditions Under One Name

Pulmonary atresia is divided into two major forms based on whether a hole exists between the heart’s two lower chambers. In pulmonary atresia with intact ventricular septum (PA/IVS), there is no such hole. The right ventricle, starved of the outflow it was supposed to pump, often remains small or underdeveloped. In PA/IVS the pulmonary valve itself is typically formed from three fused leaflets, and the pulmonary trunk may be normal in size or even enlarged.¹

In pulmonary atresia with ventricular septal defect (PA/VSD), the hole between the ventricles allows some mixing of blood, but the pulmonary trunk is very small or essentially absent. The lungs may receive blood through irregular vessels called major aortopulmonary collateral arteries (MAPCAs) that sprout from the aorta. The anatomy varies enormously from patient to patient: some have normal pulmonary arteries alongside the collaterals, some have only collaterals, and some have only native pulmonary arteries.² This heterogeneity makes PA/VSD one of the most complex congenital heart defects to manage surgically.

What Happens in the First Hours of Life

While still in the womb, a baby with pulmonary atresia can survive because the placenta handles oxygen exchange and the ductus arteriosus shunts blood past the lungs. At birth, once the baby starts breathing and the ductus begins closing, oxygen levels drop quickly. Newborns with pulmonary atresia often present with severe blueness, rapid breathing, or outright cardiovascular collapse, symptoms that can look identical to lung disease or infection.³

The emergency treatment is an intravenous infusion of prostaglandin E1 (PGE1), a drug that reopens and holds the ductus arteriosus open. In a landmark series, PGE1 nearly doubled the diameter of the ductus in infants with pulmonary atresia, and arterial oxygen levels rose from dangerously low to significantly improved within minutes to hours.⁴ PGE1 is considered life-saving for any newborn whose lung blood flow depends on a patent ductus, buying time for surgical planning.⁵ The infusion is meant to be a bridge, though, not a long-term solution. Research suggests keeping PGE1 exposure as short as possible before surgery, because prolonged use can cause structural changes in the pulmonary blood vessels.⁶

Detecting It Before Birth

Fetal echocardiography can identify pulmonary atresia during pregnancy, though the diagnosis is not always straightforward. PA/IVS in particular can be tricky because the condition sometimes progresses during gestation: what looks like severe narrowing of the valve at one scan can evolve into full atresia by a later scan. For that reason, serial ultrasound exams during the second and third trimesters are recommended when pulmonary atresia is suspected, to track changes in the right ventricle and valve.⁷

Prenatal imaging can also help predict what kind of surgery the baby will need after birth. Measurements of the tricuspid valve size, right ventricle dimensions, and the presence of abnormal coronary connections all factor into whether a two-ventricle repair or a single-ventricle strategy is more appropriate.⁸ For PA/VSD, identifying the course of the ductus arteriosus and any collateral vessels prenatally allows the surgical team to plan the approach before the baby is even born. Three-dimensional echocardiography can add spatial detail that two-dimensional imaging misses, particularly for complex vascular anatomy.⁹

The Coronary Problem in PA/IVS

One feature that makes PA/IVS especially dangerous has nothing to do with the lungs. When the right ventricle is sealed off and builds up high internal pressure, small channels called ventriculocoronary fistulae can form, connecting the right ventricle to the coronary arteries that supply the heart muscle itself. Over time, the normal coronary arteries may narrow or close entirely. This creates a situation called right-ventricle-dependent coronary circulation (RVDCC), where the heart muscle depends on the small, pressurized right ventricle for its own blood supply.

In a study of 32 patients managed for this complication, nearly all had fistulae with narrowing or complete blockage of at least two major coronary arteries, putting a large portion of the heart muscle at risk for damage if the right ventricle were decompressed surgically.¹⁰ RVDCC is one of the main reasons some patients with PA/IVS cannot have a standard two-ventricle repair: opening up the right ventricle’s outflow would lower its pressure, cutting off blood supply to the heart muscle and risking a heart attack. These patients are instead directed toward the single-ventricle surgical pathway.

Shunts, Stents, and Early Palliation

Once PGE1 has stabilized a newborn, the next step depends on the specific anatomy. For babies who need a more durable source of lung blood flow before definitive repair, two main options exist: a surgical shunt or a catheter-placed stent in the ductus arteriosus.

The modified Blalock-Taussig shunt (BT shunt) has been used for decades. It is a small synthetic tube sewn between an artery branching off the aorta and the pulmonary artery, providing a permanent bypass to deliver blood to the lungs. Duct stenting is a newer, less invasive alternative where a metal stent is placed inside the ductus arteriosus via a catheter to prop it open permanently.

A large multicenter comparison found no difference between the two approaches in the combined risk of death or emergency reintervention to treat low oxygen. However, the duct stent group had shorter intensive care stays (about five days versus nine), fewer procedural complications, and their pulmonary arteries grew larger and more symmetrically, which matters for later surgical repair.¹¹ The tradeoff is that stented patients more frequently needed additional catheter procedures later on. A smaller comparison in PA/IVS specifically found a similar pattern: shorter hospital stays with stenting (about ten days versus 23), but more reinterventions after discharge.¹²

For higher-risk patients, particularly those with RVDCC, the choice between shunt and stent may matter more. One study of high-risk patients found that those with PA/IVS and RVDCC did substantially better with duct stenting: about three-quarters reached their next surgical stage successfully, compared to universally poor outcomes in the shunt group for that specific subgroup.¹³

Unifocalization for PA/VSD With Collateral Arteries

For patients with PA/VSD whose lungs are supplied by MAPCAs rather than normal pulmonary arteries, surgery is a different problem entirely. Each collateral artery is a haphazard vessel with its own size, course, and connections. The goal of unifocalization surgery is to gather all of these collaterals, connect them to one another and to any existing native pulmonary arteries, and ultimately create a single, reconstructed pulmonary arterial system that can be connected to the right ventricle.

The reasoning behind doing this early is straightforward: collateral arteries tend to narrow and close over time, and the lung segments they supply can be permanently lost. At the same time, unprotected collaterals that carry high-pressure aortic blood can damage the lung tissue they feed. Early unifocalization aims to prevent both problems and restore a centrally connected pulmonary vascular bed.¹⁴

At experienced centers, outcomes have improved dramatically. One group reported performing 255 primary unifocalization procedures over 16 years. About 85 percent of patients were able to have a complete repair (closing the VSD and connecting the right ventricle to the new pulmonary artery system) in a single operation, with an operative death rate of about 1.5 percent.¹⁵ A broader review of published literature found that regardless of the exact surgical strategy, roughly 80 percent of patients with this condition now achieve complete repair, a figure that has transformed what was once a near-certain death sentence.¹⁶ For the remaining patients who cannot tolerate VSD closure at the time of unifocalization, a temporary shunt is placed, and most go on to have complete repair at a later date.

The Single-Ventricle Pathway

When the right ventricle is too small or too compromised to function as a pumping chamber, the heart is managed as though it has only one working ventricle. This applies to a subset of PA/IVS patients, particularly those with significant RVDCC or a severely underdeveloped right ventricle. The single-ventricle approach proceeds through a staged series of operations. The first stage provides a source of pulmonary blood flow (typically a shunt or stent, as described above). The second stage, the Glenn shunt, reroutes blood from the upper body directly into the pulmonary arteries, bypassing the heart. The third stage, the Fontan procedure, completes the circuit by also routing lower body blood directly to the lungs.¹⁷

This pathway is palliative rather than curative. It eliminates the mixing of oxygenated and deoxygenated blood, which resolves cyanosis, but the single ventricle does double the work over a lifetime, and the passive flow of blood through the lungs creates its own long-term complications. Pulmonary atresia with intact ventricular septum is one of the more common diagnoses leading to the Fontan pathway, alongside conditions like tricuspid atresia and double-inlet left ventricle.¹⁸

Genetic Connections

The causes of pulmonary atresia are not fully understood, but genetic factors play a clear role in at least some cases. The most studied genetic link involves a small deletion on chromosome 22 (known as 22q11.2 deletion, the same deletion responsible for DiGeorge syndrome). In one series of PA/VSD patients, about a third carried this deletion.¹⁹ The deletion was twice as common in PA/VSD as in standard tetralogy of Fallot, and patients who carried it were significantly more likely to have MAPCAs.²⁰ This matters for surgical planning because it suggests a more complex vascular anatomy, and it also matters for long-term care because 22q11.2 deletion is associated with immune deficiency, learning difficulties, and other issues beyond the heart.

Maternal diabetes has also been linked to an increased risk of congenital heart defects, including pulmonary atresia. In a study of pregnant women with pre-existing diabetes, over 40 percent showed abnormal findings on fetal echocardiography, with pulmonary atresia appearing among the defects identified.²¹ The absolute risk to any individual pregnancy remains low, but the association underscores the importance of careful fetal cardiac screening when maternal diabetes is present.

Living as an Adult With Pulmonary Atresia

Survival into adulthood is now the expectation for most patients who receive timely surgical treatment. After placement of a right-ventricle-to-pulmonary-artery conduit, one long-term follow-up reported survival of 93 percent at 20 years, with some patients followed as far as 48 years out from surgery.²² But survival does not mean the medical story ends. Conduit replacements are a recurring reality: only about half of patients are free from reoperation at 10 years after their first conduit, and many need second, third, or even fourth replacements over a lifetime, with a large number of those occurring during adolescence when rapid growth outpaces the conduit.²³

Even with successful repair, adults with pulmonary atresia face a high burden of ongoing health issues. In a cohort followed for a median of nearly nine years, about one in five patients died, primarily from heart failure and sudden cardiac death. Over half required hospitalization during follow-up, driven by the need for additional procedures, heart failure episodes, and arrhythmias.²⁴ Atrial arrhythmias are particularly common, affecting roughly 80 percent of adult survivors in one study, regardless of whether they had undergone a Fontan or biventricular repair.²⁵ Patients with PA/IVS who reach adulthood also show high rates of functional impairment and liver or kidney dysfunction, reflecting the cumulative toll of abnormal circulation over decades.²⁶

For the small number of patients with PA/VSD who remain unoperated into adulthood, the outlook is considerably worse. A study of these patients found that two-thirds were between 18 and 29 years old, and only two survived past 40. Among those who remained without surgery, nearly half died during follow-up. Encouragingly, adults who were offered complete repair, even at an older age, did well: ten patients who underwent hemodynamic repair after age 18 had no early or late deaths.²⁷

Neurodevelopment in Children After Surgery

Congenital heart surgery in the newborn period carries neurodevelopmental risks, and pulmonary atresia is no exception. In a study of infants who underwent neonatal surgery for tetralogy of Fallot or pulmonary atresia, average scores for thinking, language, and motor skills all fell in the low-80s, about one standard deviation below the general population mean. Roughly a quarter of patients showed significant delays in each domain. The strongest predictors of worse outcomes were the presence of chromosomal abnormalities and the occurrence of postoperative complications.²⁸

Quality of life studies paint a mixed picture. Children with PA/IVS reported more physical complaints and lower satisfaction with their activities compared to healthy peers, but the overall differences were small and did not vary by whether the child had undergone a single-ventricle or two-ventricle repair.²⁹ One nuanced finding: families reported that children with pulmonary atresia had more available time (likely reflecting activity restrictions), yet felt less supported by relatives than their healthy peers, hinting at social isolation as a subtle but real challenge.

Fetal Intervention Before Birth

For select cases of PA/IVS diagnosed in the womb, an experimental option exists: opening the atretic pulmonary valve while the baby is still in utero. The procedure, called fetal pulmonary valvuloplasty, is performed by threading a needle through the mother’s abdomen into the fetal heart and using a balloon to open the sealed valve. The goal is not to fix the defect completely but to restore enough flow through the right ventricle that it grows during the remaining months of pregnancy, potentially upgrading the baby from a single-ventricle outcome to a biventricular one.

Results from pioneering groups show the approach is technically feasible and can promote meaningful right-heart growth. In fetuses who had successful interventions, the tricuspid valve and right ventricle grew significantly more than in control fetuses with the same condition who did not receive prenatal treatment.³⁰ Another group found that after fetal valvuloplasty, the right ventricle size improved immediately due to reduced resistance, increasing the chance of a biventricular outcome.³¹ Mid-term follow-up in a small series showed that the tricuspid valve continued to develop after birth, with the most rapid growth occurring between six months and one year of age, while right ventricle growth was slower.³²

Fetal cardiac intervention remains available only at a handful of specialized centers, and patient selection is strict. Candidates typically need to have a membrane-type atresia (where the valve leaflets are identifiable but fused shut), moderate right-heart underdevelopment, and no significant coronary anomalies that would make decompression dangerous. The procedure is still considered investigational, but for the right patient, it represents a chance to change the surgical trajectory before birth.

Pregnancy in Women With Pulmonary Atresia

As more women with pulmonary atresia survive to reproductive age, the question of pregnancy safety becomes increasingly relevant. The evidence, while limited to small series, consistently shows that pregnancy is possible but carries substantial risk. In one of the larger reports, women with complex pulmonary atresia who had not undergone full repair experienced high rates of miscarriage, premature delivery, and low birth weight, along with serious maternal complications including blood clots and heart failure.³³ Women who had undergone complete biventricular repair fared better overall, with more normal-weight and full-term deliveries, but still experienced severe events in nearly half of completed pregnancies, including heart failure, arrhythmias, and pre-eclampsia complications.³⁴ In one case, progressive heart failure during pregnancy led to death 13 months after delivery. These outcomes underscore the need for expert cardiac and obstetric co-management well before conception.

Racial and Ethnic Disparities in Survival

Access to timely surgical care is a life-or-death matter for newborns with pulmonary atresia, and not all families face equal odds. A large US study examining early childhood mortality among children with congenital heart defects found that Black children with pulmonary valve atresia without VSD had roughly 2.6 times the mortality risk of white children after adjusting for other factors. Hispanic children with the same condition had about 1.8 times the risk.³⁵ The disparities likely reflect differences in prenatal detection, proximity to specialized surgical centers, insurance coverage, and follow-up care rather than biological differences in the disease itself. For a condition where delays of even hours can be catastrophic, these gaps in access translate directly into lost lives.