Truncus arteriosus
Truncus arteriosus 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.
Symptoms of truncus
arteriosus
Tthe baby can be blue, or "cyanotic," because some of the
unoxygenated blood goes to the systemic circulation.
Treatment for the
condition
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.