Transposition of the Great Arteries
Transposition of the great arteries, a complex heart defect usually found soon after birth, occurs when the pulmonary artery and the aorta are switched.
The pulmonary artery, which usually takes blood from the right side of the heart to the lungs, comes off the left side of the heart. However, the inflow to each side of the heart is normal. This means that the unoxygenated blood received by the right side of the heart goes back to the body - which is abnormal.
The oxygenated blood received by the left heart goes back to the lungs. This circulation would not allow any oxygen to get to the body which is not a survivable situation. Fortunately, there is usually an associated hole between the atria in the heart which allows some mixing of the two circulations. This allows some oxyenated blood to get to the body and some unoxygenated blood to get to the lungs. The size of the hole in the heart is sometimes inadequate and needs to be enlarged in newborns by a specially trained cardiologist.
All children with transposition of the great arteries need surgery - called an arterial switch - to correct the defect. In an arterial switch, the pulmonary artery and aorta are divided above the heart, their positions are reversed, and then they are sewn in place on the correct side. The coronary arteries - small arteries which supply the heart with blood - also need to be switched, which can be difficult, especially if in a branching pattern.
Another complicating factor with transposition of the great arteries is the large number of associated defects. Approximately 25% of patients will have a hole between the two major pumping chambers of the heart. Approximately 10% have a narrowing at the base of the pulmonary artery. Many other abnormalities are known to occur along with transposition of the great arteries, which can affect the treatment plan as well as the long-term outlook.
Surgery for transposition of the great arteries is usually done within the first two weeks of life. Even though most children do very well with the operation, it still represents major open heart surgery on a newborn. Most spend at least several days in the intensive care unit after surgery and will spend 1-3 three weeks in the hospital after surgery
For most children with transposition of the great arteries, the prognosis is excellent. If an arterial switch is successful, there is a good chance that a child may be expected to live an entirely normal life, both in terms of longevity and activity level. It cannot be overstated, however, that in transposition of the great arteries there is often a great deal of difference between individual patients. One must keep these differences in mind when evaluating children.
Note: This page is meant to be a helpful, informative introduction on the subject of transposition of the great arteries 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.