The care of critically ill infants with obstructed anomalous pulmonary venous return requires a multidisciplinary team of cardiac ICU doctors and nurses, non-invasive cardiologists and surgeons to ensure the best possible recovery.
--Catherine Allan, MD, assistant in Cardiology, Boston Children's Hospital
If your infant or child has been diagnosed with one of several forms of anomalous pulmonary venous return (or “connection”), an understanding of the condition will help you to cope with this rare and complex congenital (present at birth) heart defect. While very serious, anomalous pulmonary venous return is treatable surgically at Boston Children's Hospital, and recent surgical advances have greatly improved your child’s outlook for success.
The pulmonary veins are four blood vessels that bring oxygen-rich (red) blood from the lungs to the left atrium of the heart. Total or partial anomalous pulmonary venous return (TAPVR or PAPVR) is a rare heart defect in which all (total) or one or more (partial) of a child’s pulmonary veins do not connect normally to the left atrium. Instead, the veins are re-directed to the right atrium by way of an abnormal (anomalous) connection.
TAPVR causes varying degrees of symptoms, including cyanosis (blue-ish discoloration of skin and lips) and difficulty breathing. Severe cases will develop severe cyanosis, difficulty breathing, low blood pressure and excessive acidity in the blood (acidosis).
The defect has many forms:
- total anomalous pulmonary venous return (TAPVR)
- obstructed TAPVR—the most severe form, in which the anomalous veins are also obstructed (narrowed) prior to entering the right atrium, making it difficult for blood to return from the lungs to the heart; the baby is usually critically ill and will need emergency surgery
- unobstructed TAPVR—a less severe form, in which the child may be only mildly cyanotic and may go a few weeks or even longer before being diagnosed, at which time surgery is performed
- partial anomalous pulmonary venous return (PAPVR)—the least severe form, in which the child may show only mild signs, such as tiring easily, or may not show signs or symptoms until later in life
After surgery, most children lead healthy lives, but they will need lifelong monitoring and follow-up care.
Comparison with normal heart
In a normal heart, oxygen-poor (blue) blood returns to the right atrium from the body, travels to the right ventricle, then is pumped through the pulmonary artery into the lungs, where it receives oxygen. Oxygen-rich (red) blood returns to the left atrium from the lungs, passes into the left ventricle, then is pumped through the aorta out to the body.
Total anomalous pulmonary venous return
When a fetus is developing, the pulmonary veins are a single channel that must establish a connection to the developing left atrium. If it doesn’t connect, other pathways for pulmonary venous drainage develop.
In the various forms of total anomalous pulmonary venous return (TAPVR), the abnormal development of the pulmonary veins prevents oxygen-rich (red) blood from passing from the left atrium to the left ventricle and on to the body as it should. In all forms of TAPVR oxygen-rich blood returns to the right atrium and mixes with oxygen-poor blood coming back from the body.
In order to get blood to the left atrium and left ventricle and out to the body, some of this “mixed” blood, which has lower than normal oxygen levels, must pass through a hole (atrial septal defect or ASD) from the right atrium to the left atrium. Surgery is needed, since oxygen-poor (blue) blood cannot meet the body’s demands, either at rest or with activities.
Some babies with TAPVR also have obstruction (narrowing) of the vessels bringing blood from the pulmonary veins back to the right atrium, with two major consequences:
- Return of blood to heart is impaired, compromising the heart’s ability to pump enough blood to the body—a condition known as low cardiac output.
- The obstruction causes a “back-up” of blood flow through the veins, which leads to fluid leakage out of the pulmonary vessels (pulmonary edema) into the lung tissue, making it hard for babies to breathe and for the lungs to do their job of adding oxygen to blood and removing carbon dioxide.
As a result, babies with obstructed TAPVR may have one or more of the following signs and symptoms:
- low blood pressure and acid build-up in blood due to an inability to pump adequate amounts of oxygen and nutrient-rich blood to the body
- cyanosis resulting from both the mixing of oxygen-rich and oxygen-poor blood in the heart and the lungs’ decreased ability to oxygenate blood
- increasing difficulty breathing resulting from fluid build-up in the lungs (pulmonary edema)
Infants with obstructed TAPVR are usually critically ill immediately after birth and need emergency surgery to restore the normal blood flow from the pulmonary veins to the left atrium.
Infants who have unobstructed TAPVR are much less symptomatic. Many of these babies aren’t diagnosed until weeks or even months after birth. Although these babies usually have lower than normal oxygen levels in their blood, the degree of cyanosis is much less significant than for babies with obstructed TAPVR, and may not be noticeable.
These babies are often diagnosed when a murmur is detected by the pediatrician at a well-child visit, or because they are noted to be breathing faster or harder than normal or are growing poorly. Although surgery is also necessary for babies with unobstructed TAPVR, it can usually be scheduled as an elective procedure.
Please note: Because TAPVR is a more serious condition than PAPVR and requires treatment in infancy, we’ve emphasized TAPVR in this discussion.
TAPVR: different types of total anomalous pulmonary venous return
There are four major types of TAPVR, characterized by whether blood coming from the pulmonary veins drains to the right atrium by a vein entering from above, below, at the level of the heart or in some combination of these. For each type, there is an atrial communication that enables blood to reach the left side of the heart.
For more visual and audio information on TAPVR/PAPVR, visit our cardiovascular Multimedia Library.
How Boston Children’s Hospital approaches TAPVR or PAPVR
Our team in Boston Children’s Department of Cardiac Surgery understands how distressing a diagnosis of an anomalous pulmonary venous return can be for parents. You can have peace of mind knowing that our surgeons treat some of the most complex pediatric heart conditions in the world, with overall success rates approaching 98 percent—among the highest in the nation among large pediatric cardiac centers.
We use the following elements to provide the best possible outcomes:
- accurate diagnosis and assessment: Subtle variations in heart anatomy—such as the arrangement of the arteries that feed the heart—can negatively impact surgical outcomes if not identified ahead of time. We utilize the most advanced techniques available for precisely determining your child’s heart anatomy, with interpretation by highly experienced cardiologists.
- sophisticated and effective therapies: Babies with severe cases of TAPVR need emergency therapy. Our cardiac intensive care unit (CICU), cardiac cath labs and operating rooms deal with the urgent needs of our smallest patients 24/7. Children’s CICU was one of the first such units developed anywhere. Professionals from many countries visit our CICU to learn advanced techniques of post-operative care.
- experienced and skilled team to perform surgery and other procedures: Boston Children’s cardiac surgeons have vast experience in the surgical procedures used to repair this defect, and they work with nurses and doctors who are focused on providing expert care after surgery.
- close, expert medical follow-up: If you live in the Boston area, a Boston Children’s cardiologist will follow your child after surgical repair; if you live in another part of the country or the world, a Boston Children’s cardiologist will work closely with your local cardiologist. Adult patients with TAPVR are followed by Boston Children’s cardiologists with special training for adults with congenital heart problems.
TAPVR/PAPVR: Reviewed by Catherine Allan, MD
© Boston Children's Hospital, 2011