Tricuspid atresia
Tricuspid atresia is a birth defect of the tricuspid valve that controls the flow of blood from the right atrium (upper right chamber of the heart) to the right ventricle (lower right chamber of the heart). Tricuspid valve atresia occurs when the tricuspid valve does not form at all and blood cannot get from the right atrium through the right ventricle to the lungs for oxygen. Because a baby with tricuspid atresia may require surgery or other procedures shortly after birth, this birth defect is considered a critical congenital heart disease. Congenital means present at birth.
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 main pulmonary artery. The blood returning from the lungs is rich in oxygen and can then be pumped to the rest of the body through the aorta. In children with tricuspid atresia, the tricuspid valve that controls the flow of blood from the right atrium to the right ventricle is not formed, so blood cannot reach the right ventricle and lungs. For this reason, the right ventricle may be underdeveloped. The main pulmonary artery can also be small and carry very little blood to the lungs.
In tricuspid atresia, because blood cannot flow directly from the right atrium to the right ventricle, blood must take other routes to bypass the immature tricuspid valve. Babies born with tricuspid atresia often also have an atrial septal defect, which is a hole between the right and left atria, or a ventricular septal defect, which is a hole between the right and left ventricles. These defects allow oxygen-rich blood to mix with oxygen-poor blood so that oxygen-rich blood can be pumped to the rest of the body.
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 usually closes after birth. Keeping this junction open allows blood to reach the lungs for oxygen and bypass the small right side of the heart.
Some children with tricuspid atresia may have other heart defects, including transposition of the great arteries. When the main arteries are transposed, the main connections (arteries) of the heart are reversed. The main pulmonary artery, which normally carries oxygen-poor blood from the right side of the heart to the lungs, now originates on the left and carries oxygen-rich blood back from the lungs to the lungs. The aorta, which normally carries blood from the left side of the heart to the body, now runs from the right side and carries oxygen-poor blood back to the body. When a child has both tricuspid valve atresia and transposition of the great arteries, blood can reach the lungs because the main pulmonary artery comes from the developed left ventricle. However, the blood cannot enter the body because the aorta branches off from the deformed right ventricle and is small.
Causes and risk factors
The causes of heart defects, such as tricuspid valve 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.
Diagnostics
Tricuspid valve atresia may be diagnosed during pregnancy or shortly after childbirth.
During pregnancy
During pregnancy, screening tests (also called prenatal tests) are done to check for birth defects and other conditions. Tricuspid valve atresia can be seen on an ultrasound. Some ultrasound findings may lead to the suspicion that the child may have tricuspid valve 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 how the heart works with this defect.
After the birth of a child
Babies born with tricuspid 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 tricuspid atresia may experience additional symptoms such as:
- Respiratory problems
- Ashen or bluish skin color
- Poor feeding
- Extreme sleepiness
During a physical examination, the doctor may see symptoms such as blue skin or breathing problems. With a stethoscope, the doctor will check for heart murmurs (an abnormal "hissing" sound caused by a blockage in blood flow) or other sounds that may indicate heart problems. 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 tricuspid atresia. The most common test is an echocardiogram. This is an ultrasound of the 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 towards the heart) can also confirm the diagnosis by examining the heart and measuring blood pressure and oxygen. An electrocardiogram, which measures the electrical activity of the heart, and other medical tests may also be used to make a diagnosis.
Tricuspid valve atresia is a critical congenital heart disease that can also be detected during neonatal screening using pulse oximetry. Pulse oximetry is a simple, painless test to assess the amount of oxygen in a child's blood. The test is done using a device called a pulse oximeter, with sensors placed on the baby's skin. Low blood oxygen levels can be a sign of critical congenital heart disease. Newborn screening with pulse oximetry can detect some babies with critical congenital heart defects, such as tricuspid valve atresia, before they develop symptoms.
Treatment
Medications
Some babies and children will need medicines to help strengthen the heart muscle, lower blood pressure, and help the body get rid of excess fluid.
Nutrition
Some babies with tricuspid atresia become tired while feeding and do not gain enough weight to eat. A special high-calorie formula may be given to infants to ensure healthy weight gain. Some babies get very tired during feedings and may need to be tube fed.
Surgery
Surgical treatment of tricuspid valve atresia depends on its severity and the presence of other heart defects. Shortly after the birth of a baby with tricuspid atresia, one or more surgeries may be required to increase blood flow to the lungs and bypass the poorly functioning right side of the heart. Later, other surgeries or procedures may be required. These operations, described below, do not cure tricuspid valve atresia, but help restore the heart. Medications are sometimes prescribed to relieve the symptoms of the defect before or after surgery.
Septostomy
A septostomy can be done in the first days or weeks of a baby's life and creates or enlarges an atrial septal defect, a hole between the right and left upper chambers (atria). This is so that more oxygen-poor blood can mix with oxygen-rich blood so that more oxygen-rich blood can enter the body.
Banding
If a child has other heart defects besides tricuspid atresia, sometimes too much blood goes to the lungs and not enough to the rest of the body. Too much blood in the lungs can damage them. If this is the problem, surgery may be done in the first few weeks of a child's life to put a bandage on the artery that goes to the lungs (the main pulmonary artery) to control blood flow to the lungs. This merging is a temporary procedure and is likely to be discontinued.
Bypass procedure
This surgery is usually done within the first 2 weeks of a baby's life. Surgeons create a bypass (shunt) from the aorta to the main pulmonary artery, allowing blood to reach the lungs. If the aorta is small, as happens with transposition of the great arteries in a child, the surgeon also dilates the aorta at this time. After this procedure, the baby's skin may still appear bluish because oxygen-rich blood and oxygen-poor blood are still mixing in the heart.
Bi-directional Glenn Procedure
This is usually done when the baby is 4 to 6 months old. This procedure creates a direct connection between the main pulmonary artery and the superior vena cava, the vessel that returns oxygen-poor blood from the upper body back to the heart. This allows blood returning from the body to flow directly into the lungs and bypass the heart.
Fontan procedure
This procedure is usually performed around the age of 2 years. Doctors connect the main pulmonary artery and the inferior vena cava, a vessel that returns oxygen-poor blood from the lower body to the heart, while allowing the rest of the blood returning from the body to the lungs. After this procedure is completed, oxygen-rich blood and oxygen-poor blood no longer mix in the heart, and the baby's skin will no longer look bluish.
Babies who have these operations are not cured; they may have lifelong complications. If tricuspid valve atresia is very complex or the heart becomes weak after surgery, a heart transplant may be needed. An infant or child who receives a heart transplant will need to take medication for the rest of their life to prevent the body from rejecting the new heart.
Babies born with tricuspid atresia will need regular follow-up 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.