Pulmonary Atresia With Ventricular Septal Defect

Overview

Pulmonary atresia with ventricular septal defect (PA/VSD) occurs when there’s a hole between the two bottom pumping chambers of the heart and there’s no direct connection from the pumping chamber of the heart to the lung arteries. Sometimes, the lung's arteries are normally formed but just aren’t connected to the heart. However, in some situations, the lung arteries may be very small or absent. Instead, arterial branches to the lungs (aortopulmonary collaterals) may arise from the main artery leading to the body (aorta). Multiple aortopulmonary collateral arteries (MAPCA) may be used to describe this condition.

Often, multiple heart catheterization procedures are necessary to define the anatomy of these blood arteries and to improve the flow to the lungs before and after surgery. A number of surgeries may be necessary to bring these collateral arteries together and eventually reconnect them to the heart. Because these blood arteries are abnormal, they may develop narrowings (stenoses) that may require frequent catheterizations to widen (dilate) or stent them. These narrowings may occur within the blood arteries or in the areas where the blood arteries have been reconnected together.

PA/VSD, along with tetralogy of Fallot, interrupted aortic arch (IAA), and truncus arteriosus may be associated with DiGeorge syndrome, which is a chromosomal abnormality caused by a missing section (deletion) of the 22nd chromosome. There’s a special genetic test that can diagnose this deletion. People with DiGeorge syndrome may have problems with metabolism of calcium, absent thymus, disorders of immune function, thyroid dysfunction, cleft palate, and learning disabilities.

Treatment

Initially after birth, an assessment must be made as to how blood is getting to the lungs. In some situations, an echocardiogram will demonstrate good-sized normal pulmonary arteries that are connected together with blood coming from the ductus arteriosus. The blood supply to the lung arteries is ensured by either placement of a tube from one of the body arteries to the lungs (modified Blalock-Taussig shunt) or by placement of a stent in the ductus arteriosus. An intravenous prostaglandin E1 (PGE1) infusion may also be started to keep the ductus arteriosus open.

After the child grows, a more definitive surgical repair is performed at 6 to 12 months of age, at which time the hole between the lower chambers of the heart (VSD) is often closed with a patch, the shunt will be closed off (ligated), and a tube containing a biologic valve is placed from the heart directly to the lung arteries. As the child grows, this tube will require replacement.

If MAPCAs exist, the options will be more complicated. If these blood arteries are suspected, the baby will undergo a heart catheterization or cardiac computerized tomography (CT) scan shortly after birth in order to map out where these arteries arise and to which part of the lungs they go. Typically, PGE1 infusions are not necessary, as the ductus arteriosus may not exist. The baby may not need an initial surgery depending on a number of complicated factors. Instead, staged procedures may be considered, starting at 3 to 6 months of age. The purpose is to try to bring these blood arteries together surgically in order to recreate the lung arteriesso they will eventually be able to be connected back to the heart. These procedures are called unifocalization procedures. This process of rebuilding the lung arteries may require multiple surgical and catheter-based procedures. These arteries may become narrowed, at which time angioplasty, stenting, or further surgical repair may be considered.