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Truncus Arteriosus, Types I-IV
What is it?
There are two large arteries that leave the heart — the aorta, which carries blood to the body, and the pulmonary artery, which carries blood to the lungs.
In truncus arteriosus, the two arteries are joined to form one large common artery.
The truncus arteriosus often lies above a large hole between the septum in the right and left ventricles.
This hole is known as a ventricular septal defect.
The truncus receives low oxygen blood from the right ventricle and oxygen rich blood from the left ventricle. This mix of high and low oxygen blood is sent out to the body and to the lungs.
This explains why a baby may be blue, or cyanotic, because some of the blood without oxygen goes to the body.
How is it treated?
Surgery for this condition is most often needed early in life. It includes closing the ventricular septal defect, detaching the pulmonary arteries from the large common artery, and connecting the pulmonary arteries to the right ventricle with a cadaveric valve.
The tube will need to be replaced as the infant grows.