What is Transposition of the Great Arteries (TGA)?
The great arteries are the large blood vessels that bring blood from the heart to the body and the lungs. Normally, the right side of the heart has the great artery know as the pulmonary artery that pumps blood to the lungs. The left side of the heart has the great artery known as the aorta that pumps blood to the body. With this diagnosis, the great arteries are switched with the right heart pumping blood out to the body and receiving it back from the body, while the left heart is pumping blood out to the lungs and receiving the blood back from the lungs. Two independent circulations will occur.
How do we diagnose TGA?
Unoxygenated blood is being sent to the body, so the infant will appear blue at birth. The infant will have a small hole between the upper collecting chambers called a patent foramen ovale (PFO). The patent ductus arteriosus normally connects the aorta with the pulmonary artery. These two usually close as the infant is born. With these connections open some oxygenated blood can get to the body. The PFO can be enlarged to encourage mixing by a procedure know as the Rashkind procedure. This procedure takes place in the catheterization laboratory and requires a catheter (small flexible tube) being inserted in a big vein in the baby's groin. A catheter with a balloon will be passed across the hole in the upper chamber and pulled back to make this hole bigger to allow better mixing of the unoxygenated blood with the oxygenated blood.
How do we treat TGA?
Arterial switch is the most common surgery preformed for TGA. The heart will be stopped and opened for repair. The aorta will be cut above the where the coronary arteries come off the aorta. The pulmonary artery is cut at the same level as the aorta. The coronary arteries will be reattached to the base of the pulmonary artery with the aorta sewn to the base of pulmonary artery also. The pulmonary artery is sewn to the base of the aorta. Switching the circulation is the goal of this surgery with the pulmonary artery coming off the right ventricle and the aorta coming off the left ventricle.
© 2013 Monroe Carell Jr. Children's Hospital at Vanderbilt