Total Anomalous Pulmonary Venous Return

Normally, four lung veins (pulmonary veins) carry oxygen-rich blood from the lungs to the left atrium, and the blood is then pumped to the rest of the body. In total anomalous pulmonary venous return (TAPVR), none of the four pulmonary veins is connected to the left atrium. Instead, these veins join together and drain into the right atrium or into a large vein that flows to the right atrium. As a result, oxygen-rich blood from the lungs mixes with oxygen-poor blood from the body on the right side of the heart.

To reach the body, this mixed blood has to cross into the left atrium through an opening in the wall between the atria, namely the foramen ovale or an atrial septal defect. This opening becomes a lifeline. Because the blood circulating to the body is mixed, the baby's oxygen level is lower than normal and the skin looks bluish.

Four Types by Drainage Site

In the supracardiac type, the pulmonary veins drain into a large vein above the heart. In the cardiac type, the pulmonary veins drain directly into the right atrium or into the coronary sinus. In the infracardiac type, the flow goes down through the diaphragm to a vein in the abdomen or liver. The mixed type combines several drainage sites. The infracardiac type is more often accompanied by obstruction.

Obstructed and Unobstructed Forms

The impact of this defect depends largely on whether the pulmonary venous pathway is obstructed. If it is obstructed, blood backs up in the lungs, making them wet and stiff. The baby looks very blue and short of breath within the first hours to days and needs surgery right away. If it is not obstructed, the baby may look only slightly blue, breathe fast, have difficulty feeding, and gain weight poorly over the first weeks to months. Both forms still need surgery.

After Surgery

Surgery connects the confluence of pulmonary veins to the left atrium, closes the abnormal pathway, and closes the opening in the atrial wall. During surgery, a heart-lung machine temporarily takes over the work of the heart and lungs. Many children grow and stay active well after surgery. Some children develop narrowing of the pulmonary veins after surgery, usually within the first few months, so regular follow-up is still needed into adulthood.

This defect may be suspected when newborn pulse oximetry screening shows a low oxygen level, or when the baby looks blue and short of breath. The obstructed form often resembles severe lung disease in newborns, so doctors need to be alert when the oxygen level does not improve despite breathing support.

Echocardiography confirms the diagnosis by showing that the pulmonary veins do not drain into the left atrium, where they drain instead, and whether there is an obstruction. This test also assesses the size of the opening in the atrial wall and the lung pressure. Cardiac CT angiography helps map the path of the pulmonary veins before surgery. This defect is hard to see on a pregnancy ultrasound, so screening after birth is still important even if the pregnancy ultrasound was normal.

This defect needs prompt treatment. Take your baby to the emergency room as quickly as possible if you notice the following signs, especially in the first days and weeks after birth. For a child who has already had surgery, contact the doctor before the scheduled follow-up if symptoms come back.

• Your baby's lips, tongue, or skin look blue or grayish
• Very fast breathing, grunting, or the chest pulling inward
• Your baby refuses to feed or is very limp
• Your baby's oximetry result is low or the baby did not pass the screening
• A child who has had surgery is breathing fast again, coughing often, or has stopped gaining weight