What Is It?
Vascular ring refers to a group of abnormalities of the aorta (the large vessel that carries blood from the heart to the body) and its branches. It can cause breathing problems and feeding problems in infants and children. True or complete vascular ring refers to conditions in which abnormal vessels form a complete circle around the trachea (the breathing tube that carries air to and from the lungs) and esophagus (the tube that carries food to the stomach). (Please see diagram on next page for the positions of the trachea and esophagus.)
There are two types of complete vascular rings. They are: 1. Double Aortic Arch (see separate tutorial on this defect for details) and 2. Right aortic arch with left ligamentum arteriosum. Double aortic arch is the most common vascular ring (40%). Right aortic arch with left ligamentum arteriosum (shown) is the second most common vascular ring (30%).
With a Right aortic arch with left ligamentum arteriosum, while the aorta curves to the left after leaving the normal heart, in this defect it curves to the right. This causes the left subclavian artery (SA in diagram), which passes from the aorta into the left arm, to wrap around behind the trachea as it crosses from right to left. There may also be an aneurysm, or an out-pocketing of the left subclavian artery wall, known as Kommerell's diverticulum (KD), in the vicinity of the trachea. This can potentially increase the compression of the trachea.
In addition, the trachea is constricted by the ligamentum arteriosum (LA), which connects the pulmonary artery (PA) to the left subclavian artery (SA). (The ligamentum arteriosum is the remnant of the Ductus Arteriousus, a vessel in fetal circulation that normally closes soon after birth.)
Thus, the so-called Vascular Ring consists of a retroesophageal left subclavian artery (and often its attached Kommerell's diverticulum), the ligamentum arteriosum, and the pulmonary artery - all of which encircle and may constrict the breathing tube and esophagus.
This rare defect affects boys and girls equally.