Coarctation of the Aorta

It is customary to include in any discussion of congenital heart disease coarctation of the aorta , even though it is a vascular, not a cardiac, malformation. It involves a congenital narrowing of the aorta in the region where the aortic arch changes into the descending aorta. This stenosis is usually severe, bordering on complete interruption of flow into the descending aorta. The flow of arterial blood into the head and upper extremities is unimpaired, but the rest of the body has to receive blood via a detour—collateral circulation. Branches of the aorta supplying blood to the upper part of the body form connections with branches of the descending aorta, especially arteries supplying the chest that run between the ribs. These connections function so that when some of the arterial blood meant for the upper parts of the body reaches the arteries in the chest, it flows in the opposite direction, into the descending aorta. As a consequence of the abnormally high resistance caused by redirection of the blood, patients usually suffer from high blood pressure, which may overload the left ventricle and cause its hypertrophy.

Coarctation of the aorta accounts for many cases of high blood pressure in infants, children, and adolescents. Such hypertension is curable, disappearing when the coarctation is corrected. Although

hypertension is the most serious consequence of coarctation, rare complications include infective endarteritis, stroke caused by small aneurysms of an artery supplying the brain, and aortic dissection (see chap. 14).