Coarctation of the Aorta

The aorta is the main blood vessel originating from the heart taking blood to the body.  A coarctation of the aorta is a localized narrowing that is typically found just below the takeoff of the artery to the left arm.  Coarctation of the aorta is a congenital heart defect, in other words, a birth defect of the heart. Congenital heart defects are the most common form of birth defects, occurring in approximately 1 in 150 individuals.  Coarctation is one of the more common congenital heart defects; the overall incidence is 0.5-0.8 per 1000. The cause of coarctation is not entirely clear; some experts speculate that coarctation is caused by abnormal constriction of the aorta during the closure of a normal in utero structure, the ductus arteriosus.  Coarctation is often associated with other heart defects, such as a bicuspid aortic valve and/or aortic valve stenosis.

Physiologically, coarctation creates a situation in which the left ventricle must squeeze more forcefully to pump blood past the narrowed segment of the aorta. The burden on the left ventricle is directly related to the degree of narrowing. A more narrowed aorta results in more stress being placed on the left ventricle. In cases of mild coarctation, there is little if any extra workload placed on the heart, while severe coarctation may result in considerable stress.  Typically coarctation results in a higher than normal blood pressure in the arms, and a lower than normal blood pressure in the legs.

Symptoms from coarctation in older children are generally uncommon.  Infants with severe coarctation may develop a rapid respiratory rate or signs of impaired blood flow to the body. Occasionally older children with long standing, significant coarctation may develop symptoms with exercise such as fatigue and leg cramps.

Diagnosis of coarctation can be made in a number of different ways. Often older children are identified due to unexplained high blood pressure.  In addition, a patient may come to attention due to the presence of a heart murmur. This simply refers to the sound that blood is making as it flows past the narrowed segment of aorta. There are many other different causes of heart murmurs, including normal causes. An echocardiogram uses sound waves to visualize the aorta and is often the easiest means to show the degree of narrowing.

The majority of patients with a significant coarctation will ultimately require surgery to repair it.  This prevents long term damage to the heart as well as the negative consequences of long-standing high blood pressure.  The surgery usually involves cutting out the narrowed segment and reattaching the ends of the aorta.  In this day and age, the success rate for surgical repair of a straightforward coarctation is very high, on the order of 98-99%.  Most operations go well with little or no complications.  A small percentage of patients may develop a recurrent coarctation months to years following surgery due to the presence of scar tissue.  This can often be fixed with a less invasive procedure, a cardiac catheterization.