Total Anomalous Pulmonary Venous Return (TAPVR)
Total anomalous pulmonary venous return (TAPVR) is a congenital heart disease. In a child with TAPVR, oxygen-rich blood does not return from the lungs to the left atrium. Instead, oxygen-rich blood returns to the right side of the heart. Here oxygen-rich blood mixes with oxygen-poor blood. This leads to the fact that the child receives less oxygen than the body needs. To survive with this defect, children with TAPVR usually have a hole between the right and left atria (atrial septal defect) that allows mixed blood to reach the left side of the heart and pump to the rest of the body. . In some children, in addition to an atrial septal defect, there may be other heart defects with TAPVR. Because a child with this defect may require surgery or other procedures shortly after birth, TAPVR is considered a critical congenital heart disease. Congenital means present at birth.
In a related defect, partial anomalous pulmonary venous return (PAPVR), not all veins have an abnormal connection. Abnormal connections are present, but one or more veins normally return to the left atrium. Therefore, PAPVR is not as critical as TAPVR.
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 returning from the lungs is rich in oxygen and passes through the pulmonary veins into the left atrium. The left side of the heart pumps oxygen-rich blood to the rest of the body through the aorta.
Types of total anomalous pulmonary venous return (TAPVR)
There are different types of TAPVR depending on the connection of the pulmonary veins:
- Supracardiac: In supracardiac TAPVR, the pulmonary veins merge and form an abnormal connection above the heart with the superior vena cava, which is a large blood vessel that carries oxygen-poor blood from the upper body to the heart. In this type of TAPVR, a mixture of oxygen-poor and oxygen-rich blood returns to the right atrium through the superior vena cava.
- Cardiac: In cardiac TAPVR, the pulmonary veins join behind the heart and join with the right atrium. The coronary sinus, which is a vein that helps return oxygen-depleted blood from the heart muscle to the heart, helps connect the pulmonary veins to the right atrium in this type of TAPVR.
- Infracardiac: In infracardiac TAPVR, the pulmonary veins converge and form abnormal connections below the heart. The mixture of oxygen-poor blood and oxygen-rich blood returns to the right atrium from the veins of the liver and inferior vena cava, which is the main blood vessel that carries oxygen-poor blood from the lower body to the heart. .
Causes and risk factors
The causes of heart defects such as TAPVR 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 risk factors, such as what the mother or fetus comes into contact with in the environment, or what the mother eats or drinks, or the medications she uses.
Diagnosis
PAPVR and TAPVR can be diagnosed during pregnancy, but most often these defects are diagnosed shortly after the baby is born.
During pregnancy
During pregnancy, screening tests (also called prenatal tests) are done to check for birth defects and other conditions. TAPVR can be diagnosed during pregnancy with an ultrasound. Some ultrasound results may lead a doctor to suspect that a child may have TAPVR. 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. However, the TAPVR defect is usually not detected during pregnancy. It is difficult for doctors to see the pulmonary veins during prenatal screening tests because little blood enters the lungs before the baby is born. This defect is easier to detect after birth, when blood passes through the lungs and returns to the heart.
After the birth of a child
Symptoms usually occur at birth or shortly after. Babies with TAPVR may have a bluish skin color called cyanosis because their blood cannot carry enough oxygen. Infants with TAPVR or other conditions that cause cyanosis may have symptoms such as:
- Problems breathing
- Pounding heart
- Weak pulse
- Ashen or bluish skin color
- Poor feeding
- Extreme sleepiness
With the help of a stethoscope, a doctor often hears a heart murmur (an abnormal "hissing" sound caused by blood flowing through an atrial septal defect). However, heart murmurs are often absent from birth.
If a doctor suspects a problem, they may order one or more tests to confirm a diagnosis of TAPVR. 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 can also confirm the diagnosis by showing that the blood vessels are not properly attached. An electrocardiogram, which measures the electrical activity of the heart, a chest x-ray, and other medical tests can also be used to make a diagnosis.
TAPVR is a critical congenital heart disease that can also be detected by pulse oximetry screening in newborns 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 disease, such as TAPVR, before they develop symptoms.
Treatment
Children with TAPVR will need surgery to repair the defect. The age at which the operation is performed depends on the health of the child and the structural features of the abnormal connections between the pulmonary veins and the right atrium. The goal of surgical treatment of TAPVR is to restore normal blood flow to the heart. To correct this defect, doctors typically connect the pulmonary veins to the left atrium, close any abnormal connections between blood vessels, and close the atrial septal defect.
Babies whose defects are repaired by surgery are not cured; they may have lifelong complications. A child or adult with TAPVR will need to see a cardiologist regularly to monitor their progress, avoid complications, and check for other health problems that may develop with age.