Total Anomalous Pulmonary Venous Return
What is Total Anomalous Pulmonary Venous Return (TAPVR)?
The normal heart has four chambers: two upper chambers called atria, which receive blood into the heart, and two lower chambers called ventricles, which pump blood out of the heart. Ordinarily, unoxygenated (blue) blood comes back from the body into the right atrium, moves into the right ventricle, and then is pumped out of the right ventricle through the pulmonary artery (the main artery to the lungs) to collect more oxygen. From the lungs, the now oxygenated (red) blood goes through four pulmonary veins to enter the left atrium, moves into the left ventricle, and is pumped out to the rest of the body through the aorta (the body’s main artery) – completing the cardiac cycle.
Total anomalous pulmonary venous return (TAPVR) is a rare congenital (present at birth) condition in which the pulmonary veins that carry oxygenated blood from the lungs into the heart are anomalous – abnormal – and do not connect properly to the left atrium. Instead, as the baby’s heart forms during the first eight weeks of the mother’s pregnancy, the baby’s blood vessels connect to other veins that empty into the right atrium.
If one or more of the pulmonary veins connect in the left atrium (the correct place), but not all the veins, the condition is called PAPVR, or partial anomalous pulmonary venous return.
When all four pulmonary veins are connected improperly, the baby also develops a hole, known as an atrial septal defect or ASD, in the tissue between the two atria that allows the mixed blood – oxygenated and unoxygenated – to reach the left side of the heart and then be pumped out to the body. The ASD helps the newborn survive, but it also makes the baby’s heart have to work even harder to provide blood and oxygen to the rest of the body.
There are four types of TAPVR, defined by where the veins drain to the right atrium, be it from above, below or into the heart directly.
Pulmonary veins drain to the right atrium via a vertical vein that collects the blood behind the left atrium and carries it upward to a vein above the heart that drains to the superior vena cava (the main vessel that transports oxygen-poor blood from the upper body to the right atrium)
Pulmonary veins connect directly to the right atrium, or drain into the right atrium via a vein called the coronary sinus
Pulmonary veins drain to a vein below the diaphragm – often liver veins or the inferior vena cava, which is the main vessel that transports oxygen-poor blood from the lower body to the heart – before draining into the right atrium
Pulmonary veins connect randomly to the heart
Sometimes, the abnormal veins become narrowed or blocked at the entrance before they enter the right atrium, making it hard for blood to move from the lungs to the heart. This is considered a cardiac emergency, requiring prompt surgery. As the blood from the lungs cannot return to the heart because of the blockage or narrowing, the pressure in the lungs climb, and it becomes difficult to breathe. Acid levels in the blood can rise, making the child very ill.
If there is no blockage, the baby may not be diagnosed for weeks or months, and only then will surgery be needed, generally within the infant’s first few months.
What are the causes?
TAPVR is a congenital heart defect. It is so rare that TAPVR and PAPVR together affect only about one in 10,000 infants. While genes and environment can raise risks, TAPVR most often happens by chance.
How is it diagnosed?
TAPVR may be diagnosed during pregnancy with a fetal echocardiogram, which is a specialized ultrasound of the fetal heart. The affiliated physicians in the Fetal Cardiology Program at The Fetal Center will confirm a diagnosis and prepare a delivery plan for both mom and baby. A multidisciplinary team of specialists will also develop the baby's immediate care plan following delivery.
If TAPVR is not diagnosed in utero, and suspicion of a heart defect occurs after the baby is born, a pediatrician will refer the patient to a pediatric cardiologist to determine the diagnosis.
Signs of TAPVR include a bluish tint to lips, nails and skin, rapid breathing and sometimes a heart murmur – or whooshing sound – heard via a stethoscope. The worst cases are obvious at birth: Newborns may have difficulty breathing, an extreme bluish tint (from a lack of oxygen in the blood), a pounding heart, weak pulse, clammy skin, blood pressure issues or high acidity in the blood (acidosis).
The mildest cases may not reveal themselves for weeks or months via minor clues such as tiring easily. Doctors may order further testing after noticing rapid or difficult breathing, or poor growth.
The following tests may be utilized to find more details:
- Pulse oximetry, a small and painless gadget placed on a finger, which may reveal low oxygen rates from an inefficient heart.
- Chest X-rays, which create images of the heart and lungs, making major flaws visible, such as fluid buildup in the lungs.
- A cardiac echocardiogram (echo), using sound waves (ultrasound) to produce images of the heart and blood vessels’ structures on a screen. This reveals whether the heart is pumping properly.
- An electrocardiogram (EKG or ECG), a painless exam, which checks the heart’s electrical action to reveal damage or irregular rhythms, suggesting problems with the heart.
- A cardiac MRI (magnetic resonance imaging), using radio waves, magnets and a computer to form three-dimensional images of the heart, which can reveal structural abnormalities (such as an enlarged right ventricle).
- Cardiac catheterization, which involves a thin, long tube that is inserted into a blood vessel and guided into the heart. The doctor can see more details of a mixed TAPVR and widen the ASD or narrowed vessels at that time, to boost blood oxygen levels short-term.
How is it treated?
Treatment of TAPVR is surgery, which consists of placing the patient on the heart-lung machine (cardiopulmonary bypass) and making the connection between the pulmonary veins and the left atrium. Fortunately, in most cases of TAPVR, all four pulmonary veins come to a central place (called a confluence) just behind the left atrium and a full anatomical repair can be achieved. However, after surgery, scar tissue may form around the connection between the pulmonary veins and the left atrium. If the scar tissue formation is severe enough, additional surgery may be required in the future.
If your child has a form of TAPVR that is obstructed (where the blood cannot get to the heart from the lungs), this may require an emergent surgical intervention. This is often performed when the child id only hours old. If the pulmonary veins are unobstructed, surgery can take place at an agreed upon elective date, usually at a few weeks of life.
Recovery from surgery is most closely related to the health of the lungs going into surgery. Although surgery for TAPVR has improved over the years, mortality from TAPVR repair is still fairly high, approximately 5-8% overall. This will vary greatly from child to child depending on the kind of TAPVR and the amount of pulmonary venous obstruction before surgery.
What are the long-term effects?
The most critically ill newborns may need to use a ventilator (breathing machine) after surgery overnight or for several days as their lungs recover. The baby will be observed closely – first in the intensive care unit and then elsewhere in the hospital – before being discharged..
What follow-up care is needed?
The pediatric cardiologist will monitor the child long-term and may prescribe medication to prevent an infection of the heart’s lining (endocarditis) or an odd heartbeat (arrhythmia). Between 15 to 20 percent of TAPVR babies may need cardiac catheterization or surgery later in life to repair narrowed veins. They will be monitored by their cardiologist for the rest of their life, to make sure they do not develop an erratic heartbeat, clots, leaky valves or blocked blood vessels.
Why choose the Children’s Heart Program?
As part of the Children’s Heart Program at Children’s Memorial Hermann Hospital, the affiliated cardiologists and affiliated cardiovascular surgeons collaborate as a multidisciplinary team to treat babies prior to birth, infants, children and young adults with congenital and acquired heart disorders. The team of affiliated physicians, nurses and coordinators work together with you to determine the best treatment plan for your child. Your child’s referring physician is also kept fully informed of your child’s treatment plan.
At Children’s Memorial Hermann Hospital, the affiliated cardiologists and affiliated cardiovascular surgeons understand the unique challenges, circumstances and intricacies of caring for young patients with heart conditions. In addition to the team’s medical expertise, Children’s Memorial Hermann Hospital provides families with patient-centered care, keeping families fully involved as part of the child’s treatment team as well as offering resources to meet the needs of your entire family.
Pediatric Cardiology Clinic
The University of Texas Health Science Center Professional Building
6410 Fannin, Suite 370
Houston, TX 77030
Phone: (832) 325-6516
Pediatric Cardiovascular Surgery Clinic
The University of Texas Health Science Center Professional Building
6410 Fannin, Suite 950
Houston, TX 77030
Clinic Phone: (832) 325-7234
Nurse Line: (713) 500-7324
Note: This page is meant to be a helpful, informative introduction on the subject of TAPVR in children. The information may not be applicable to all cases, especially if there are additional defects. It is not meant to replace the opinion of a personal physician.
04/2016 – This page was updated and approved by an affiliated pediatric physician at the Children’s Heart Program.