AORTA, COARCTATION OF THE

congenital condition involving constriction, or narrowing, of a short section of that portion of the aorta that arches over the heart. The aorta is the principal artery conducting blood from the heart into the systemic circulation. The partial obstruction of the aorta's channel causes a characteristic murmur and causes abnormally high blood pressure in the arms. The left ventricle (lower left chamber of the heart) is usually enlarged. Blood flow to the abdomen, pelvis, and legs is reduced. Intercostal (between-the-ribs) branches from the aorta enlarge and cause characteristic notching of the ribs. Treatment of the defect is surgical and varies with the age of the person affected. In infants the artery that supplies the left arm is tied, divided, and used as a flap to repair the narrowed aortic area. In children and adolescents the narrow section of the aorta is removed, and the two free ends are sewn together. In older persons, either the constricted section of artery is replaced with a section of Dacron tubing, or the defect is left but is bypassed by a Dacron tube opening into the aorta on either side of the defecta sort of permanent bypass for the blood flow. Surgery for this condition is most effective in the young and is rarely performed on patients over 50.