Definition of Double aortic arch:

Double aortic arch is an abnormal formation of the aorta, the large artery that carries blood from the heart to the rest of the body. It is a congenital problem, which means that it is present at birth.

See also: Vascular ring

Causes, incidence, and risk factors:

Double aortic arch is a common form of a group of defects that affect the development of the baby' s aorta in the womb. These defects cause an abnormal formation called a vascular ring -- a circle of blood vessels.

Normally, the aorta develops from one of several curved pieces of tissue (arches). As babies develop in the womb, the arches split into several parts. The body breaks down some of the arches, while others form into arteries. A normally developed aorta is a single arch that leaves the heart and moves leftward.

In double aortic arch, some of the arches that should have changed into arteries or disappeared are still present at birth. Babies with a double aortic arch have an aorta that is made up of two vessels instead of one. The two parts to the aorta have smaller arteries branching off of them. As a result, the two branches go around and press down on the windpipe and the tube that carries food from the mouth to the stomach (esophagus).

A double aortic arch may occur in other congenital heart defects, including:

• A chromosome defect
• Tetralogy of Fallot
• Transposition of the great arteries
• Ventricular septal defect

Double aortic arch is very rare. Vascular rings make up a small percentage of all congenital heart problems. Of these, a little more than half are caused by double aortic arch. The condition occurs equally in males and females.