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Pulmonary atresia is a rare congenital cardiac defect in which there is complete absence or interruption of the pulmonary artery lumen, leading to no direct communication between the right ventricle and the pulmonary artery. It results in impaired pulmonary blood flow, often requiring collateral circulation for lung perfusion.
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As in Pulmonary Atresia with VSD, this defect is also associated with complete obstruction of the Pulmonary Artery. However, as there is no associated VSD, blood is diverted from the right atrium to the left atrium via the Foramen Ovale. The right ventricle (RV) is usually small (Hypoplastic), though its wall may be thickened (Hypertrophied). Survival depends on the ductus remaining open in the early days of life (in order for blood to reach the lungs), Most babies will need a 'Shunt' operation during infancy, involving insertion of a tiny piece of artificial tube (made from Goretex) between the Aorta, or a branch (usually one of the arm arteries), and one of the branch Pulmonary Arteries.Complete repair may be possible, but often necessitates several operations.
Cardiology : Pulmonary Atresia with intact ventricular septum. Rch.org.au. Published 2025. Accessed July 11, 2025. https://www.rch.org.au/cardiology/heart_defects/Pulmonary_Atresia_with_intact_ventricular_septum/
This defect is a form of Tetralogy of Fallot in which there is complete obstruction of the Pulmonary Artery resulting in total diversion of blood from the right ventricle into the aorta. Survival depends on the ductus remaining open in the early days of life (in order for blood to reach the lungs), or on the presence of other connecting blood vessels between the Aorta and the Pulmonary Arteries in the lungs (Collaterals). Most babies will need a 'Shunt' operation during infancy, involving insertion of a tiny piece of artificial tube (made from Goretex) between the Aorta, or a branch (usually one of the arm arteries), and one of the branch Pulmonary Arteries. Complete Repair is carried out at two to three years. Complete repair for Pulmonary Atresia is usually carried out after the first year of life, though sometimes it may be performed earlier.
Cardiology : Pulmonary Atresia with VSD. Rch.org.au. Published 2025. Accessed July 11, 2025. https://www.rch.org.au/cardiology/heart_defects/Pulmonary_Atresia_with_VSD/
| Type | Description |
|---|---|
| 1. PA with intact ventricular septum (PA–IVS) | – No communication between RV and PA |
| – Intact interventricular septum | |
| – Often associated with a hypoplastic right ventricle | |
| 2. PA with VSD (PA–VSD) | – Similar to Tetralogy of Fallot with atretic pulmonary valve |
| – Large VSD allows RV to LV blood flow | |
| – Pulmonary perfusion via collateral arteries (MAPCAs) or PDA | |
| 3. Isolated unilateral PA | One pulmonary artery (usually right) is absent or atretic |
| – Contralateral lung is normal | |
| – Collateral flow supplies the atretic side |
| Age of Onset | Features |
|---|---|
| Neonatal period | Cyanosis, respiratory distress, murmur |
| Infancy/Childhood | Failure to thrive, fatigue, recurrent respiratory infections |
| Older children/adults | Hemoptysis, exercise intolerance (esp. in isolated unilateral PA atresia) |
Chest X-ray (CXR):
| Findings | Notes |
|---|---|
| PA–IVS | Normal or small heart, decreased pulmonary vascularity |
| PA–VSD | Cardiomegaly, decreased PBF, or MAPCAs leading to patchy vasculature |
| Unilateral atresia | Small hemithorax, shifted mediastinum, hyperlucent lung |
Other modalities:
| Modality | Findings |
|---|---|
| Echo | First-line for PA–IVS and PA–VSD |
| • Atretic pulmonary valve | |
| • RV hypoplasia or hypertrophy | |
| • Presence of ASD/VSD | |
| • PDA or MAPCAs | |
| CTA | – Confirms absence of pulmonary artery continuity |
| – Detects MAPCAs and PDA | |
| – Excellent for surgical planning | |
| CMR | – Evaluates ventricular function, flow quantification |
| – Preferred for serial follow-up (no radiation) | |
| Cardiac Catheterization | • Used to map collateral vessels and assess pulmonary artery pressure |
| • May allow interventional shunt creation or balloon procedures |