What is Total Anomalous Pulmonary Venous Return?
Total Anamolous Pulmonary Venous Return (TAPVR) or also known as Total Anamolous Pulmonary Venous Connection (TAPVC) is a congenital heart defect where the pulmonary veins that bring the oxygenated blood from lungs connect to wrong place in the heart instead of the left atrium. As a result the body receives less oxygenated blood.
What is TAPVR?
Pulmonary veins that carry oxygen rich blood connect to the wrong place in the heart causing the oxygen rich blood to mix with oxygen poor blood, which is then pumped through the body. All babies born with TAPVR also have Atrial Septal Defect or ASD which causes the blood in the two atrial chambers to mix.
Related: What are Congenital Heart Defects
Signs of Down Syndrome during Pregnancy
TAPVR Types
Based on where the pulmonary veins connect to the heart, there are different types of TAPVR:
Supracardiac TAPVR: The most common type of TAPVR, where the pulmonary veins come together behind the heart and join to Superior Vena Cava.
Infracardiac TAPVR: The pulmonary veins come together behind the heart and join to Interior Vena Cava and the Hepatic Veins
Cardiac TAPVR: The pulmonary veins come together behind the heart and join to coronary sinuses.
Mixed TAPVR: The most rarest type of TAPVR, where the pulmonary veins connect to more than one place, a combination of above types making it very complex and difficult to correct.
TAPVR Causes
What causes any of the birth defects is not very clear but many scientists and doctors believe that some of the risk factors like mentioned below could increase the chances of having a baby with TAPVR / TAPVC.
Baby born with Down Syndrome.
Sometimes it runs in families, but rare.
Viral infections during pregnancy like Rubella
Other factors like use of medication, recreational drugs, drinking alcohol, smoking, or poor maternal diet during pregnancy.
Advanced maternal age, above 40.
TAPVR Symptoms
Some babies show symptoms right after birth like blue, grey tint of skin, difficulty breathing, while others may not be diagnosed for weeks or during physical exam by doctor. In any case some of the common symptoms of TAPVR / TAPVC are:
Cyanosis: Most babies with TAPVR develop a blue or purple tint of the skin due to low oxygen levels in blood.
Babies with obstructed pulmonary veins show signs immediately after birth like cyanosis (visible blue skin, lips, tongue), rapid breathing and irritability.
Heart Murmurs
Easily getting tired or Sleeping excessively
Difficulty Feeding
Difficulty gaining weight
TAPVR Diagnosis
TAPVR / TAPVC is diagnosed in most cases shortly after birth or during the physical exam by doctor. It is very rarely diagnosed during pregnancy.
During Pregnancy: The doctor performs an ultrasound called anomaly scan to see whether all the major organs are developing, In some cases the doctor could detect issues with the heart and may ask for a foetal echocardiogram to assess the heart further.
After Birth: Babies with TAPVR (more pronounced if there is an obstruction in veins) may start showing symptoms within minutes to first few weeks of life like blue tinted skin, fast breathing, sweating, difficulty to feed, heart murmurs, etc. and the doctor may ask for an echo to confirm the same.
Physical Exam: Doctors may hear a murmur during physical exam and may ask for more tests to confirm. The murmur usually gets obvious at around 3-6 weeks of age.
TAPVR Testing
There are multiple tests that can be used to detect TAPVR / TAPVC as listed below:
Pulse Oximeter: Device that is put on the baby's toe to monitor oxygen saturation levels. It is very effective in detecting low oxygen levels.
Echocardiogram - Most commonly used form of test as it uses sound waves to form the image of the heart and see it's functioning/structural changes. It is quick, painless, non-invasive and accurate, hence preferred form of testing.
Chest X-Ray - TAPVR can cause structural changes to the heart which can be seen on x-rays. The technician may also inject a substance in the blood that highlights the circulation and any defects on the x-ray.
Electrocardiogram - or ECG uses multiple sensors stuck to your child's chest to measure electrical activity of the heart that shows up as a wave or graph on the screen that can be printed. Any structural changes or issues with the heart, the wave patterns change this helps doctors to assess the extent of impact of TAPVR.
CT Scan - X-ray images of the chest / heart are processed by a computer to form a 3D image of the heart to see any structural changes and impact of TAPVR on the heart. An injectable substance is used to highlight on the screen and help with images.
Cardiac Catheterization - The doctor inserts the catheter device from your upper thigh into the major blood vessel to look in your heart to see the defects. Not commonly used unless the doctor suspects a blood clot, blood vessel damage, high blood pressure in the lungs or an enlarged heart that needs a closer look.
TAPVR Surgery
The surgery is done based on the baby's condition, age, and severity of TAPVR. In case of obstructed TAPVR the baby may need correction immediately after birth while in non obstructive the surgery may be done days to weeks after diagnosis.
During the surgery the surgeon will connect the pulmonary veins to the left ventricle and will close off any other connections to the heart. Once this is done, the ASD or atrial septal defect is closed as well.
TAPVR Life Expectancy
Babies who undergo timely surgery usually have a very good outcome with survival rates higher than 95%, but without surgery and proper treatment they may develop complications over time and in some cases of TAPVR could also become fatal. In case of obstructive TAPVR, immediate surgery after birth may be needed, outcome depends on the baby's condition and ability to withstand the surgery.
TAPVR Outlook / Prognosis
Outlook for babies with early diagnosis and surgical correction of TAPVR is very good with most babies thriving and growing up as their healthy peers into adulthood. They may still need life long visits to cardiologists to ensure the heart is functioning as it should and no new complications like pulmonary vein obstruction or arrhythmia developing. Some babies may develop complications post surgery and or may need to use medication, have additional surgeries later in life to correct any new or existing issues post surgery.