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Pulmonary atresia is a congenital heart defect where the pulmonary valve is malformed and blocks blood flow to the lungs. Treatment involves surgery, such as the Blalock-Taussig shunt or Fontan procedure, and regular monitoring. Valve replacements may be necessary as the child grows.
Pulmonary atresia is a congenital heart defect in which the pulmonary valve does not form properly and completely blocks the passage of blood to the lungs. The primary function of the pulmonary valve is to return blood to the lungs to collect oxygen. When the valve is so malformed that it provides no path to the smaller pulmonary arteries, heart failure is imminent unless treated surgically.
Often, pulmonary atresia is accompanied by other defects. A variant of Tetralogy of Fallot often occurs with pulmonary atresia. In other cases, both the pulmonary valve formation and the right ventricle are affected. This serious but rare set of defects, called hypoplastic right heart syndrome, cannot be corrected, but is addressed either through staged Fontan surgeries or through transplantation.
Alone or accompanied by other defects, pulmonary atresia should be treated during the first days of a child’s life. Diagnosis, if not prenatal, is usually made once the baby is born, when the newborn will appear intensely cyanotic or blue. Although all babies appear a little blue soon after delivery, they turn pinker as oxygenated blood flows through their system. A child with pulmonary atresia, however, does not turn pinker, but can actually become even paler and more cyanotic within minutes.
Obstetricians present or other medical personnel will notice cyanosis. If necessary, the child is transferred to a facility with a pediatric cardiology and surgery department for immediate treatment. Luckier parents may have a prenatal diagnosis of pulmonary atresia through ultrasound, or may give birth to their children in a hospital with a cardiology department, so relocation is not necessary. In both cases, the diagnosis will be confirmed shortly after birth with a fetal echocardiogram, an ultrasound of the heart.
Before surgery, your child is often given an intravenous drug, prostaglandin E, which helps keep the patent duct from closing. This small hole in the atrial septal wall normally closes within hours of birth. It creates a passage for mixing oxygenated and non-oxygenated blood, thus allowing some of the oxygenated blood to reach the body of a child with pulmonary atresia.
Prostaglandin E can only work for a few days before heart failure occurs. The next step for many children with pulmonary atresia is surgery. Cardiothoracic surgeons perform a Blalock-Taussig (BT) shunt, which replaces the patent ductus. The shunt is a tiny tube that allows blood to be mixed so that the tissues can receive oxygen-rich blood. Even with the shunt, an affected newborn’s oxygen saturation levels are often between 80-85%, compared to the normal rate of 96-100%.
Although in most people, low oxygen would be fatal, this is not the case for a child with a BT shunt. Infants and young children can survive with this reduced oxygenation, although it can affect growth, cause clubbing of the extremities, and eventually lead to heart failure. The BT shunt is only a first step, however, used to give a child time to grow before repairs are attempted when possible. In Tetralogy of Fallot with pulmonary atresia, surgeons may choose to forgo the shunt and fix the defects all at once, including replacing the pulmonary valve with a porcine, bovine, or donor valve. It is considered standard to have the pulmonary valve replaced every eight to ten years, as the child will outgrow the valve.
In the hypoplastic right heart with pulmonary atresia, the Fontan procedure is performed in stages during the first years of life. In the final stage, the malformed pulmonary valve is simply removed and the stump stitched into the heart. To prevent blood clots, children who have had a valve replacement or Fontan should take low-dose aspirin every day.
When pulmonary atresia occurs on its own, surgeons perform a valve replacement. However, pulmonary atresia by itself is quite rare. Valve replacements should be monitored and replaced as the child grows.
Once the surgical repair is complete, the child requires annual heart monitoring. However, even in the presence of a hypoplastic right heart, surgical techniques guarantee a good outcome for the child, even if the transplant is necessary 15-30 years after Fontan. For the child with uncomplicated pulmonary atresia, the outlook is excellent, although future surgeries will be needed to replace oversized valves.
