Before you begin reading about transposition of the great arteries, please read the explanation of how the normal heart works for a basic understanding of its structure and function.
View Large Transposition of the Great Arteries IllustrationTransposition of the great arteries (TGA) is a complex congenital heart defect in which the two large arteries that carry blood out of the heart are connected to the heart abnormally:
Normally, blood flows in this pattern: body » right side of heart » lungs » left side of heart » back to body. The pulmonary artery carries blue blood from the right side of the heart to the lungs where it picks up oxygen. The aorta carries red blood from the left side of the heart to the body. In children with TGA, the normal pattern of flow does not exist, and the body doesn't get enough oxygenated (red) blood.
The symptoms of TGA include:
Transposition of the great arteries may be diagnosed before birth, with fetal echocardiogram (ultrasound). Our Fetal Heart Program will prepare a plan for delivery and care immediately after birth.
Sometimes TGA is diagnosed when an infant is a few hours or days old. Less commonly, in some cases, infants may not have visible symptoms for weeks or months. Pediatricians from other hospitals refer newborns to the Cardiac Center when they notice symptoms or abnormal values on laboratory testing such as pulse oximetry.
Diagnosis of TGA may require some or all of these tests:
Transposition of the great arteries is unpredictable. Approximately one-third of newborns with TGA have extremely low oxygen levels that can harm their bodies and will require an urgent intervention, called a balloon atrial septostomy (BAS), within hours after birth. This life-saving procedure, which creates or enlarges a hole between the upper chambers of the heart to allow red and blue blood to mix, was developed at The Children’s Hospital of Philadelphia in the 1960s.
For babies requiring a BAS procedure, the clock begins ticking at the moment of birth and access to immediate expert care is essential. At CHOP, we may recommend that these babies be delivered in our Garbose Family Special Delivery Unit, which is just steps away from our cardiac operative and catheterization facilities.
All children with transposition of the great arteries will require open-heart surgery to treat the defect. Without surgical repair, the overwhelming majority of patients with TGA will not survive their first year. The surgery, known as the arterial switch operation, is typically performed within a few days of birth. Surgeons reconstruct the heart so that the aorta is attached to the left ventricle and the pulmonary artery is attached to the right ventricle.
After surgery your child will recover in our Evelyn and Daniel M. Tabas Cardiac Intensive Care Unit (CICU).
Children who have had surgical repair of TGA require life-long care by a cardiologist. The cardiologist may ask for heart tests, including ECGs, echocardiograms, cardiac MRIs and exercise stress tests. The cardiologist may also evaluate your child’s cholesterol level especially if there is a family history of adult acquired heart disease.
The cardiologist will look for any narrowing where the blood vessels were sewn together. Mild vessel narrowing is usually well tolerated, but more severe narrowing may require intervention. Evaluation of long-term heart muscle function and valve function is also very important. In particular, the former pulmonary valve and surrounding tissue that now functions as the new aortic (or “neo-aortic”) valve and root on the left side of the heart can stretch over time leading to valve leakage. As with all complex congenital heart conditions, additional surgeries may be required as the child grows. Ongoing medication use is uncommon.
Our pediatric cardiologists follow patients until they are young adults, coordinating care with the primary care physicians.
We will help patients transition to an adult cardiologist.
The Philadelphia Adult Congenital Heart Center, a joint program of The Children's Hospital of Philadelphia and the Hospital of the University of Pennsylvania, meets the unique needs of adults who were born with heart defects.
Until approximately 25 years ago, infants with transposition of the great arteries were managed by alternative surgical procedures, sometimes referred to as the "Senning" or "Mustard" operations. As a result, we don't yet know the truly long-term effects of the arterial switch operation beyond young adulthood. It is anticipated that the overwhelming majority of children born with TGA will go on to lead healthy, productive lives. Significant limitations of day-to-day activities, including sports, are uncommon. However, prudent physical activity after complex congenital heart surgery is recommended and is best individualized with the patient’s cardiologist.
Contact the Cardiac Center at The Children's Hospital of Philadelphia for a second opinion or for more information.
Reviewed by: Marie M. Gleason, MD
Date: October 2013
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