Aortopulmonary Window
When babies are born with a direct “side-to-side” connection of the aorta to the main pulmonary artery, it is a condition known as aortopulmonary (AP) window.
Key Points
- An AP window is rare, accounting for less than 0.5% of congenital heart disease.
- 50% of patients with AP window also have another heart defect.
- Open-heart surgery is needed to repair the defect and prevent the development of heart failure or pulmonary hypertension.
What is AP window?
An AP window occurs during heart development when there is an abnormal opening between the aorta and main pulmonary artery.
- The aorta is the blood vessel that moves oxygenated blood from the heart to the rest of the body.
- The pulmonary artery is the blood vessel that moves deoxygenated blood returning to the heart to the lungs for oxygen exchange to occur.
When an AP window occurs, blood from the aorta can move easily into the pulmonary artery, causing too much blood to flow through the lungs. This can lead to permanent damage and result in pulmonary hypertension.
An AP window is rare congenital heart defect, accounting for less than 0.5% of all congenital heart disease. There is a higher incidence in males than in females.
What causes an AP window?
An AP window is caused by an issue in the development of the heart, where there is incomplete separation of the two arteries. It is not known why this defect occurs. While some genetic links have been identified, there is no known genetic cause of AP window.
What are the defects associated with AP window?
Up to 50% of patients with AP window also have another cardiac defect. These can include:
- Coarctation of the aorta and its most severe form, interrupted aortic arch
- Patent ductus arteriosus
- Transposition of the great arteries
- Tetralogy of Fallot
- Ventricular septal defect (VSD) or atrial septal defect (ASD)
- Pulmonary artery and coronary artery abnormalities
An AP window is also one of the conditions that make up Berry syndrome, a rare congenital heart syndrome that is characterized by a combination of several heart defects.
What are the symptoms of AP window?
Symptoms of AP window in babies can include:
- Difficulty feeding
- Delayed growth
- Rapid breathing
- Irritability
- Frequent tiring
- Rapid heartbeat
- Respiratory infections
How is AP window diagnosed?
An AP window is typically diagnosed within the first several weeks to months of the baby’s life. When the defect is suspected, the baby’s doctor will conduct a thorough physical examination, including listening to the heart for abnormalities.
The testing needed to diagnose an AP window includes:
An AP window can sometimes be diagnosed before birth using fetal echocardiography, though it is a difficult diagnosis that may be missed prenatally given differences in blood circulation before birth and after the baby is born.
How is AP window treated?
AP window requires surgery to patch the opening between the aorta and the pulmonary artery. This is an open-heart surgery that is done shortly after birth.
Babies with additional cardiac defects sometimes have them repaired during the same surgery.
Surgery Recovery
After surgery, the child is taken to the cardiac intensive care unit for recovery. Following surgical repair, they will return with a chest tube and other invasive lines for close monitoring and medication administration. A breathing tube may be necessary for support after surgery. Babies are discharged once all supportive devices and lines are no longer needed and they are back to standard respiratory support and eating habits. The baby will need close follow-up with their pediatric cardiologist following discharge.
Babies who are under 1 month of age and require repairs for complex congenital heart defects are typically recommended for a neurodevelopmental screening before they turn 2.
Can AP window be diagnosed in adults?
In rare instances, an AP window is not recognized in childhood and diagnosed in adulthood. An echocardiograph is used to confirm the diagnosis and severity of the defect. A cardiac catheterization procedure may be used to measure the severity of pulmonary hypertension, if present.
The defect may be closed surgically or through a catheterization procedure. Lifelong cardiology follow-up is required following open-heart surgical repair.
What is the outlook for babies with AP window?
Babies without additional cardiac defects who have their AP window treated typically go on to be active with no exercise limitations.
A delay or avoidance of treatment can result in complications, including:
- Congestive heart failure
- Pulmonary hypertension
- Eisenmenger syndrome
- Death
Determining safe levels of activity for patients who received treatment later in life will depend on whether pulmonary hypertension, pulmonary vascular obstructive disease (PVOD) or Eisenmenger syndrome are present. This will be evaluated by the cardiologist.
An existing or repaired window increases risks associated with pregnancy. A cardiologist should be consulted to review the risks prior to and during pregnancy to help guide with recommendations.
Medically reviewed by Benjamin Barnes, M.D., M.S., and Courtney Elyse Wein, D.O., March 2, 2026
