Transposition of the great vessels: MedlinePlus Medical Encyclopedia

P Transposition of the great vessels is a heart defect that occurs from birth (congenital). The 2 major vessels that carry blood away from the heart -- the aorta and the pulmonary artery -- are switched (transposed).

T Causes
P The cause of most congenital heart defects is unknown.
P Factors in the mother that may increase the risk for this condition include:
- Age over 40
- Alcoholism
- Diabetes
- Poor nutrition during pregnancy (prenatal nutrition)
- Rubella or other viral illness during pregnancy
P Transposition of the great vessels is a cyanotic heart defect. This means there is decreased oxygen in the blood that is pumped from the heart to the rest of the body.
P In normal hearts, blood that returns from the body goes through the right side of the heart and pulmonary artery to the lungs to get oxygen. The blood then comes back to the left side of the heart and travels out the aorta to the body.
P In transposition of the great vessels, the blood goes to the lungs, picks up oxygen, returns to the heart, and then flows right back to the lungs without ever going to the body. Blood from the body returns to the heart and goes back to the body without ever picking up oxygen in the lungs.
P Symptoms appear at birth or very soon afterward. How bad the symptoms are depends on the type and size of additional heart defects (such as atrial septal defect, ventricular septal defect, or patent ductus arteriosus) and how much the blood can mix between the 2 abnormal circulations.

T Symptoms
P Symptoms may include:
- Blueness of the skin
- Clubbing of the fingers or toes
- Poor feeding
- Shortness of breath

T Exams and Tests
P The health care provider may detect a heart murmur while listening to the chest with a stethoscope. The baby's mouth and skin will be a blue color.
P Tests often include the following:
- Cardiac catheterization
- Chest x-ray
- ECG
- Echocardiogram (if done before birth, it is called a fetal echocardiogram)
- Pulse oximetry (to check blood oxygen level)

T Treatment
P The baby will immediately receive a medicine called prostaglandin through an IV (intravenous line). This medicine helps keep a blood vessel called the ductus arteriosus open, allowing some mixing of the 2 blood circulations.
P A procedure using a long, thin flexible tube (balloon atrial septostomy) may be needed to create a large hole in the atrial septum to allow blood to mix.
P A surgery called an arterial switch procedure is used to permanently correct the problem within the baby's first week of life. This surgery switches the great arteries back to the normal position and keeps the coronary arteries attached to the aorta. Prior to the development of this surgery, a surgery called an atrial switch (or Mustard procedure or Senning procedure) was used. There are still many people alive who had this surgery.

T Outlook (Prognosis)
P The child's symptoms will improve after surgery to correct the defect. Most infants who undergo arterial switch do not have symptoms after surgery and live normal lives. If corrective surgery is not performed, the life expectancy is only months.

T Possible Complications
P Complications may include:
- Coronary artery problems
- Heart valve problems
- Irregular heart rhythms (arrhythmias)

T When to Contact a Medical Professional
P This condition can be diagnosed before birth using a fetal echocardiogram. If not, it is most often diagnosed soon after a baby is born.
P Go to the emergency room or call the local emergency number (such as 911) if your baby's skin develops a bluish color, especially in the face or trunk.
P Call your provider if your baby has this condition and new symptoms develop, get worse, or continue after treatment.

T Prevention
P Women who plan to become pregnant should be immunized against rubella if they are not already immune. Eating well, avoiding alcohol, and controlling diabetes both before and during pregnancy may be helpful.

T Alternative Names
P Transposition of the great arteries; TGA; d-TGA; Congenital heart defect - transposition; Cyanotic heart disease - transposition; Birth defect - transposition

T Patient Instructions
- Pediatric heart surgery - discharge

T Images
- Heart, section through the middle
- Heart, front view
- Transposition of the great vessels

T References
P Fraser CD, Carberry KE. Congenital heart disease. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 19th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 59.
P Kliegman RM, Stanton BF, St Geme JW, Schor NF. Cyanotic congenital heart lesions. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 430.
P Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital heart disease. In: Mann DL, Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 62.

T Review Date 10/22/2015
P Updated by: Larry A. Weinrauch, MD, Assistant Professor of Medicine, Harvard Medical School, Cardiovascular Disease and Clinical Outcomes Research, Watertown, MA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

