The Heart Institute

Truncus Arteriosus

In the normal heart there are two main vessels leaving the pumping chambers: the aorta, which carries blood to the body from the left side; and the pulmonary artery, which carries blood to the lungs from the right heart. In the defect known as Truncus, the two main vessels are fused into one large channel into which both pumping chambers empty. There is a hole (ventricular septal defect or VSD) between the two lower chambers which allows both to pump into the common channel.

As the common channel leaves the heart, there is branching with vessels going to the lungs, while the main channel continues to the body. The major problem in Truncus is that the lungs are flooded with blood and the heart muscle is overloaded. Infants with Truncus usually are in distress in the first few days of life because of the severe overcirculation of the lungs, and early surgical attention is required.

The operation for Truncus involves separating the pulmonary blood vessels from the truncal vessel. Then a synthetic tube (conduit) containing a heart valve is connected to the right-sided pumping chamber (right ventricle) at one end, and to the pulmonary artery at the other end. The hole between the two pumping chambers also must be closed with a patch of synthetic material.

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