Transposition of the great vessels

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Alternative names
Transposition of the great arteries

Definition
Transposition of the great vessels is a congenital heart defect in which the 2 major vessels that carry blood away from the heart—the aorta and the pulmonary artery—are switched (transposed).

Causes, incidence, and risk factors

The cause of most congenital heart defects is unknown. Prenatal factors associated with a higher than normal incidence of these disorders include maternal rubella or other viral illnesses during pregnancy, poor prenatal nutrition, maternal Alcoholism, maternal age over 40, and Diabetes, although it is unclear if any of these actually cause the problem.

Transposition of the great vessels is classified as a cyanotic heart defect because the condition results in insufficiently oxygenated blood pumped to the body which leads to cyanosis (a bluish-purple coloration to the skin) and Shortness of breath.

In transposition of the great vessels, there is no communication between the pulmonary circulation and the systemic circulation. Fresh oxygenated blood from the lungs returns to the heart ready to nourish the body, but instead is whisked right back to the lungs. Conversely, oxygen-poor blood returns from the body to the heart and is then sent right back out to the body without being reoxygenated. There is usually an associated defect that permits the mixing of the systemic and pulmonary circulation to provide some oxygenated blood to the body. Without such a defect, the condition is rapidly fatal.

Symptoms appear at birth or very soon afterwards. The severity of the symptoms depends upon the type of associated defect and the resulting amount of oxygenated blood supplied to the general circulation. The condition affects approximately 40 out of 100,000 infants. It is the most common cyanotic heart defect identified in the first week of life.

Symptoms

• Blueness of the skin
  
• Shortness of breath
  
• Poor feeding
  
• Clubbing of the fingers or toes

Signs and tests

The health care provider may detect a heart murmur while listening to the chest with a stethoscope.

Tests often include the following:

• chest x-ray
  
• Cardiac catheterization
  
• ECG
  
• Echocardiogram

Treatment
Immediately after diagnosis, a medication called prostaglandin is started intravenously to maintain the small connection (the ductus arteriosus) between the pulmonary and systemic circulations. Surgery to temporarily adjust the vessels may be required shortly after birth, with permanent correction postponed until the child is older. However, a surgical technique known as an arterial switch procedure allows permanent correction within the first month of life.

Expectations (prognosis)
Improvement in symptoms and growth and development is seen after surgical correction of the defect. If corrective surgery is not performed, the life expectancy is shortened.

Complications

• Arrhythmias
  
• Heart valve problems

Calling your health care provider

This condition is usually diagnosed when a baby is born. Go to the emergency room or call the local emergency number such as 911 if your baby’s skin develops a bluish color.

Call the health care provider if your baby has this disorder and new symptoms develop, become worse over time, or if symptoms continue after treatment.

Prevention
Women who plan to become pregnant should be immunized against Rubella if they are not already immune. Good nutrition, avoiding alcohol, and control of Diabetes both before and during pregnancy may be helpful.

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