Aorto-pulmonary Window (AP Window in children) is a very rare congenital heart defect (CHD) which is associated with a hole between ascending aorta (vessel that supplies pure blood to the body) & pulmonary artery (vessel that supplies impure blood to the lungs).
Due to this hole, there is shunting of blood from aorta to pulmonary artery with high pressure that can lead to overflow of blood to the lungs.
Generally it is associated with other complex cardiac diseases (like coarctation of the aorta, interrupted aortic arch, ventricular septal defect, tetralogy of fallot, atrial septal defect etc), but can also occur as an isolated anomaly.
AP window types
There are 3 types of AP window. Most common type is Type 1 and is most commonly amenable for transcatheter closure of AP window.
Symptoms of AP window
Excess blood flow from aorta to both lungs leads to very high pressures in both lungs. Blood flow to lungs depends on size of aorto-pulmonary window in children.
If size of AP window or hole is large then it can leads to heart failure and child presents with difficulty in breathing, excess sweating during feeding, poor weight gain etc.
With small AP window, child is generally not having symptoms but detected on routing examination by a paediatrician by hearing murmur of AP window in children.
If Large AP window not treated on time then it can results in bluish discolouration of lips and fingers and later on results in inoperable state known as Eisenmenger syndrome.
Whenever AP window is present, it is large in size in most of the cases.
Sometimes, it is often missed even during assessment by a cardiologist when AP window is associated with other complex cardiac lesions.
AP window diagnosis
AP Window can be diagnosed even before delivery of the baby by doing Fetal Echocardiogram test. Most of the AP window defects can be diagnosed by doing Fetal Echo Test.
“Echocardiography of child” is essential for making the diagnosis of AP window in children.
Supportive tests that can be done are chest x ray and ECG.
Occasionally, “pediatric cardiac catheterization’’ needs to be done for determining whether child is operable or not when AP window is not treated on time.
AP window Treatment
If AP window is large in size, then only option for treatment is by doing open heart surgery as quickly as possible (preferably before 6 months of age).
If size of AP window is small, then we can follow up for few months and if suitable then we can close AP window by “device closure of AP window” in cath lab (instead of open heart surgery).
In moderate size AP window, then depending on size and location of AP window, we can plan either device closure or open heart surgery.
AP window surgery:
This is done by open heart surgery by opening of the chest in midline.
Pregnancy and AP window
Pregnant women with repaired AP window with no signs of pulmonary arterial hypertension (PAH) pose no significant problems during pregnancy.
Pregnancy is contraindicated with established Eisenmenger complex like situation as it poses risk both to the mother and child.
Outcome of AP window
Child who either underwent surgical repair or angiographic closure of AP window (early closure) has no significant problems in long term with no restrictions in their activities.
Those who are inoperable due to AP window (Eisenmenger AP window) advised activity restrictions.