Anomalous pulmonary venous return (TAPVR)
Total pulmonary venous anomalies may occur in isolation or in combination with other types of congenital heart defects. There can be varying numbers and combinations of venous anomalies, usually in specific patterns, ranging in severity from mild to very complex.
In total anomalous pulmonary venous return (TAPVR), all four pulmonary veins carrying oxygenated blood from the lungs to the heart return through persistent venous channels to the right side of the heart in an anomalous (abnormal) way, making a newborn appear blue, or cyanotic, rather than to the left atrium as normal. The infant’s prognosis depends on multiple factors, including where the anomalous veins return and whether or not they are obstructed or patent (open). TAPVR is considered a critical heart defect, and an infant may need surgery or other procedures not long after birth.
TAPVR prevents the baby from receiving the needed amount of oxygen, and usually is accompanied by a hole between the right and left atria (an atrial septal defect) that allows the mixed oxygenated and non-oxygenated blood to enter the left side of the heart and be pumped out to the rest of the body, enabling the infant to survive. Other heart defects may exist along with TAPVR and the atrial septal defect.
Partial anomalous pulmonary venous return (PAPVR) refers to the condition when fewer than four pulmonary veins return to the right side of the heart. In PAPVR, some veins have abnormal connections, but others return blood to the heart’s left atrium through normal channels. PAPVR is less critical than TAPVR.
The cause of TAPVR is unknown. Some heart defects occur because of genetic or chromosomal mutations. Others may be caused by these combined with environmental, dietary or medicinal risk factors to the mother or fetus.
Single anomalous pulmonary veins are likely to be completely asymptomatic, often incidentally diagnosed at older ages. Infants with TAPVR may look blue (cyanosis), because their blood is oxygen-depleted. They also may have symptoms such as:
- Problems breathing
- Pounding heart
- Weak pulse
- Poor feeding
- Extreme sleepiness
According to where the pulmonary veins connect, there are three types of TAPVR:
The pulmonary veins converge, creating an abnormal connection above the heart to the superior vena cava (main blood vessel bringing oxygen-poor blood from the upper body to the heart). A mixture of oxygenated and oxygen-poor blood returns to the right atrium through the superior vena cava.
The pulmonary veins converge behind the heart and connect to the right atrium. Oxygen-depleted blood is brought from the heart muscle back to the heart through the coronary sinus, a vein that helps connect pulmonary veins to the right atrium.
Pulmonary veins converge to create abnormal connections below the heart. A mixture of oxygen-poor blood and oxygenated blood flows back to the right atrium from the veins of the liver and the inferior vena cava (the main blood vessel bringing oxygen-poor blood to the heart from the lower body.
TAPVR and PAPVR may be diagnosed during pregnancy, but more often they are discovered soon after birth. The following screening or prenatal tests may be given during pregnancy:
- Fetal echocardiogram
- Electrocardiogram (EKG)
TAPVR is not commonly detected during pregnancy; more is revealed after birth, when your physician can see the blood flowing to the lungs and returning to the heart. A stethoscope allows a doctor to hear a heart murmur (caused by blood flowing through the atrial septal defect). However, a heart murmur may not be present immediately after birth. Tests for infants include:
- Cardiac catheterization to confirm the diagnosis by showing the blood vessels abnormally attached
- Chest X-rays
- Pulse oximetry, a painless test used to measure the oxygen level (oxygen saturation) of the blood
Treatment of pulmonary venous anomalies depends on the location and extent of the defect, and how sick the child is. Early complete surgical repair is warranted. During surgery, the pulmonary veins are redirected to connect to the left atrium and the defect between the right and left atrium is closed, restoring normal blood flow through the heart. Even with surgical repair, the condition is not cured; those with TAPVR may have lifelong complications, requiring regular follow-up visits with a cardiologist to monitor progress, avoid complications and check for any relevant health conditions that might develop as they get older.