Truncus arteriosus (common arterial trunk) means that there is one common vessel or trunk from the heart instead of a separate pulmonary artery and aorta. There is only one valve between the heart and this trunk. Normally, the pulmonary artery carries the pulmonary circulation — the blood that goes to the lungs, and the aorta carries the systemic circulation — the blood that goes throughout the rest of the body.
In truncus arteriosus, the trunk carries both the pulmonary and systemic circulation, as well as the coronary circulation, which normally arises off the aorta. The trunk overrides both ventricles, and there is always a ventricular septal defect (VSD), a hole in the wall between the lower two chambers of the heart. In truncus arteriosus, the oxygenated blood mixes with unoxygenated blood in the heart through the VSD. All the blood goes through the trunk and can either proceed through the trunk or go into the pulmonary artery and go to the lungs without ever carrying oxygen to the body.
Heart with Truncus Arteriosus
The baby can be blue, or "cyanotic," because some of the unoxygenated blood goes to the systemic circulation.
Because excess blood can repeatedly go to the lungs, the lungs get "flooded." To restrict this flow, a procedure known as pulmonary artery banding can be performed early in life. Pulmonary artery banding is usually not open-heart surgery, and the heart does not need to be stopped. A band, usually made of Gore-Tex, a material similar to rain gear, is placed around the pulmonary artery. This, in essence, kinks the pulmonary artery and restricts the blood from going to the lungs and forces it to the body.
Pulmonary artery banding is a palliative procedure — a fix, not a cure. Complete repair is usually a modification of a Rastelli procedure. Generally, a Rastelli procedure connects the right ventricle to the pulmonary artery using a tube-like connection. This tube is usually a homograft, made from human cadaver tissue. During the Rastelli procedure, the ventricular septal defect is closed with a Gore-Tex patch so that the aorta arises solely from the left ventricle.
Untreated, tricuspid atresia will usually result in death in infancy. With surgical treatment, lifestyle is fair to good, but probably not normal due to some limitation in exercise capability. This varies from patient to patient. There is the risk of the development of rhythm abnormalities, which may alter lifestyle and lifespan and may require medical or other types of treatment. If there is a residual hole allowing blue blood to go to the body (right to left shunt), there is a risk of stroke.
The function of the heart may worsen over time requiring treatment with medicine or even cardiac transplantation. Similar to other heart defects, preventive measures against bacterial endocarditis are required for life. Children with tricuspid atresia should have lifelong follow-up.