What Is Transposition of the Great Arteries?
Transposition of the great arteries is a serious birth defect in which the two large blood vessels leaving the heart are switched.
Normally, the pulmonary artery leaves the right ventricle and carries oxygen-poor (blue) blood to the lungs. The aorta leaves the left ventricle and carries oxygen-rich (red) blood to the body.
In babies with this birth defect, the pulmonary artery and aorta are reversed. The pulmonary artery leaves the left ventricle, and the aorta leaves the right ventricle.
This means oxygen-poor blood flows in a loop from the heart out to the body and back to the heart. Oxygen-rich blood flows in a loop from the heart to the lungs and back to the heart. So the baby’s body is not getting enough oxygen and appears blue.
Transposition of the Great Arteries in Children
Babies with this condition survive if they also have a heart defect that lets oxygen-rich blood get from their lungs and heart to the rest of their body. This could be an atrial septal defect (ASD) or a ventricular septal defect (VSD).
With atrial septal defect
ASD is a hole in the septum between the baby’s atria. In babies with transposed arteries, this hole allows some oxygen-rich blood to leak from their left atrium into their right atrium. This blood mixes with oxygen-poor blood. The mixture flows into their right ventricle and gets pumped out to their body.
It’s normal for babies to have a hole, called the foramen ovale, between their atria while they are developing in the womb. This hole should close shortly after birth. In some babies, the hole doesn’t close all the way. A patent (open) foramen ovale is another way that blood from the atria can mix in babies with transposed arteries.
With ventricular septal defect
VSD is a hole in the septum between the baby’s ventricles. In babies with transposed arteries, this hole allows some oxygen-rich blood to leak from their left ventricle into their right ventricle. This blood mixes with oxygen-poor blood and gets pumped out to their body.
Patent ductus arteriosus
A patent ductus arteriosus (PDA) may also help with circulation in babies with transposed arteries.
PDA means that a small blood vessel near the heart, called the ductus arteriosus, fails to close after a baby is born. Before birth this vessel joins the pulmonary artery to the aorta. It allows blood to bypass the lungs during fetal growth. Normally it closes within a few days after birth. If it doesn’t close, it’s called patent (open) ductus arteriosus.
In babies with transposed arteries, PDA allows some blood to flow between their pulmonary artery and their aorta.
Transposition of the Great Arteries at Seattle Children’s
Our heart team has treated many children with transposition of the great arteries. In a typical year, we see 10 to 15 children with this condition. We have extensive experience with the surgery these patients require. We also have a pediatric cardiac anesthesia team and a cardiac intensive care unit to help care for children who undergo heart surgery.
When you come to Children's, a team of people will take care of your child. Along with your child's cardiologist, you are connected with other providers such as neonatologists, pulmonologists (lung doctors), nurses, child life specialists, social workers and others, if their expertise is needed. We work together to meet all of your child's health needs and help your family through this experience.
Since 1907, Children's has been treating children only. Our team members are trained in their fields and also in meeting the unique needs of children. For example, the doctors who give your child anesthesia are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age. Our expertise in pediatrics truly makes a difference for our patients and families.