Pulmonary atresia
Pulmonary atresia is a birth defect in the pulmonic valve, which is the valve that controls the flow of blood from the right ventricle (lower right chamber of the heart) to the main pulmonary artery (the blood vessel that carries blood from the heart to the lungs). Pulmonary atresia occurs when this valve has not formed at all and blood cannot flow from the heart's right ventricle to the lungs. Because a child with pulmonary atresia may require surgery or other procedures shortly after birth, this birth defect is considered a critical >congenital heart disease.
In a child without congenital heart disease, the right side of the heart pumps oxygen-poor blood from the heart to the lungs via the pulmonary artery. The blood that returns from the lungs is rich in oxygen and can then be pumped to the rest of the body. In infants with pulmonary atresia, the pulmonic valve that normally controls blood flow through the pulmonary artery is not formed, so blood cannot pass directly from the right ventricle to the lungs.
In pulmonary atresia, since blood cannot flow directly from the heart's right ventricle into the pulmonary artery, blood must take other routes to bypass the immature pulmonary valve. The foramen ovale, the natural opening between the upper right and left heart chambers during pregnancy that usually closes after the baby is born, is often left open to allow blood flow to the lungs. In addition, doctors may give the baby medicine to keep the baby's patent ductus arteriosus open after the baby is born. A persistent ductus arteriosus is a blood vessel that allows blood to pass through a baby's lungs before birth, and it also usually closes after birth.
Types of pulmonary atresia
There are usually two types of pulmonary atresia, depending on whether the child has a ventricular septal defect (a hole in the wall that separates the heart's two lower chambers, or ventricles):
- Pulmonary atresia with intact ventricular septum: In this form of pulmonary atresia, the wall or septum between the ventricles remains intact and intact. During pregnancy, when the heart is growing, very little blood enters or exits the right ventricle, causing the right ventricle to develop incompletely and remain very small. If the right ventricle is underdeveloped, it can be difficult for the heart to pump blood to the lungs and body. The artery that normally carries blood from the right ventricle, the main pulmonary artery, remains very small because the pulmonary valve does not form.
- Pulmonary atresia with a ventricular septal defect: In this form of pulmonary atresia, a ventricular septal defect allows blood to enter and exit the right ventricle. Therefore, the blood circulating in the right ventricle may contribute to the expansion of the ventricle during pregnancy, so it is usually not as small as in pulmonary atresia with an intact ventricular septum. Pulmonary atresia with ventricular septal defect is similar to another condition called tetralogy of Fallot. However, in tetralogy of Fallot, a pulmonic valve forms, although it is small and blood passes through it with difficulty - this is called pulmonic valve stenosis. Thus, pulmonary atresia with a ventricular septal defect is similar to a very severe form of tetralogy of Fallot.
Causes and risk factors
The causes of heart defects such as pulmonary atresia are unknown in most children. Some children develop heart defects due to changes in their genes or chromosomes. It is also believed that heart defects are caused by a combination of genes and other factors, such as things the mother comes into contact with in the environment, or what the mother eats or drinks, or certain medications the mother comes into contact with. uses.
Diagnosis
Pulmonary atresia can be diagnosed during pregnancy or shortly after the baby is born.
During pregnancy
During pregnancy, screening tests are done to check for birth defects and other conditions. Pulmonary atresia can be seen during an ultrasound. Some ultrasound findings may lead the doctor to think that the child may have pulmonary atresia. If so, the doctor may order a fetal echocardiogram to confirm the diagnosis. A fetal echocardiogram is a special ultrasound examination of the baby's heart and major blood vessels that is performed during pregnancy. This test can show problems with the structure of the heart and the proper functioning of the heart.
After the birth of a child
Children born with pulmonary atresia present with symptoms at or shortly after birth. They may have a bluish skin color called cyanosis because their blood cannot carry enough oxygen. Infants with pulmonary atresia may have additional symptoms such as:
- Respiratory problems
- Ash or bluish skin color
- Bad nutrition
- Extreme sleepiness
During a physical examination, the doctor may see symptoms such as blue skin or breathing problems. Your doctor will use a stethoscope to check for a heart murmur (an abnormal "hissing" sound caused by a blockage in blood flow). However, heart murmurs are often absent from birth.
If a doctor suspects a problem, they may order one or more tests to confirm the diagnosis of pulmonary atresia. The most common test is an echocardiogram. This test is an ultrasound of the baby's heart, which can show problems with the structure of the heart, such as holes in the walls between the chambers and any irregular blood flow. Cardiac catheterization (insertion of a thin tube into a blood vessel and direction to the heart) can also confirm the diagnosis by examining the heart and measuring blood pressure and oxygen levels. An electrocardiogram, which measures the electrical activity of the heart, and other medical tests may also be used to make a diagnosis.
Pulmonary atresia is a critical congenital heart disease that can be detected during newborn screening using pulse oximetry. Pulse oximetry is a simple bedside test to measure the amount of oxygen in a baby's blood. Low blood oxygen levels can be a sign of critical congenital heart disease. Newborn screening with pulse oximetry can detect some infants with critical congenital heart defects, such as pulmonary atresia, before they develop symptoms.
Treatment
Most babies with pulmonary atresia will need medication to keep the ductus arteriosus open after birth. If this blood vessel is kept open, blood will flow to the lungs until the pulmonic valve is repaired.
Treatment for pulmonary atresia depends on its severity.
In some cases, blood flow can be improved with a cardiac catheterization (insertion of a thin tube into a blood vessel and towards the heart). During this procedure, doctors may expand the valve with a balloon or place a stent (small tube) to keep the ductus arteriosus open.
In most cases of pulmonary atresia, the baby may need surgery shortly after birth. During surgery, doctors widen or replace the pulmonary valve and widen the passage to the pulmonary artery. If the child has a ventricular septal defect, the doctor will also place a patch on the ventricular septal defect to close the hole between the two lower chambers of the heart. These actions will improve blood flow to the lungs and the rest of the body. If a child with pulmonary atresia has an underdeveloped right ventricle, he may need a staged operation similar to the surgical correction of the hypoplastic left heart syndrome.
Most children with pulmonary atresia need regular visits with a cardiologist to monitor their progress and check for other health problems that may develop as they get older. As adults, they may need more surgeries or medical attention to deal with other possible problems.