Medical Q&As

Transposition of the great arteries?

What treatment needs to be given to a baby that has transposition of the great arteries?

Transposition of the great arteries is a congenital anomaly. The normal circulatory system is configured in such a way that blood flows through the veins back to the right-sided chambers of the heart, namely the right atrium and right ventricle. The blood is then pumped into the lungs through the pulmonary artery and it is oxygenated in the lungs, which converts the venous blood from a blue colour to a bright red colour because it is now oxygen enriched. The blood then flows back into the left atrium and then passes into the left ventricle from which it is then pumped into the aorta, which is the main artery of the body. The blood is then pumped through the various organ systems of the body where the oxygen is extracted and the blood then flows into the network of veins and is conveyed back to the heart where the cycle of oxygenation is again repeated. In the case of transposition of the great arteries the pulmonary artery comes out of the left ventricle, instead of the right, and the aorta comes out of the right ventricle, instead of the left. Babies born with this anomaly are often referred to as “blue babies” because they have a dusky blue hue to their skin, which arises from the inadequate oxygenation of their blood. The technical name for this bluish discolouration is cyanosis. Transposition of the great arteries is usually associated with defects in the septum or partition that separates the right and left sides of the heart. There are several forms of surgical repair available and the nature of the repair that is performed depends on the child’s age and general condition. The commonest repair, and this easiest one to visualize in your mind, involves reversing the connections of the aorta and pulmonary artery. This involves disconnecting the aorta from the right ventricle and disconnecting the pulmonary artery from the left ventricle. The aorta is the connected to the left ventricle and the pulmonary artery is connected to the right ventricle thus reversing the congenital anomaly. There are other procedures that can be performed but they are quite difficult to visualize and would require complex drawings so that you could understand the way that the circulation through the heart was being re-configured. However, reversing the connections of the great arteries is the procedure that is most frequently performed.