Truncus arteriosus is a rare type of heart disease in which a single blood vessel (truncus arteriosus) comes out of the right and left ventricles, instead of the normal 2 vessels (pulmonary artery and aorta). It is present at birth (congenital heart disease).
There are different types of truncus arteriosus.
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In normal circulation, the pulmonary artery comes out of the right ventricle and the aorta comes out of the left ventricle, which are separate from each other.
With truncus arteriosus, a single artery comes out of the ventricles. There is most often also a large hole between the 2 ventricles (ventricular septal defect). As a result, the blue (without oxygen) and red (oxygen-rich) blood mix.
Some of this mixed blood goes to the lungs, and some goes to the rest of the body. Often, more blood than usual ends up going to the lungs.
If this condition is not treated, two problems occur:
Too much blood circulation in the lungs may cause extra fluid to build up in and around them. This makes it hard to breathe.
If left untreated and more than normal blood flows to the lungs for a long time, the blood vessels to the lungs become permanently damaged. Over time, it becomes very hard for the heart to force blood to them. This is called pulmonary hypertension, which can be life threatening.
Surgery is needed to treat this condition. The surgery creates 2 separate arteries.
In most cases, the truncal vessel is kept as the new aorta. A new pulmonary artery is created using tissue from another source or using a man-made tube. The branch pulmonary arteries are sewn to this new artery. The hole between the ventricles is closed.
Complete repair most often provides good results. Another procedure may be needed as the child grows, because the rebuilt pulmonary artery that uses tissue from another source will not grow with the child.
Untreated cases of truncus arteriosus result in death, often during the first year of life.
Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.