From the Latin word “to press together,” coarctation of the aorta is a condition in which the walls of the aorta are pinched, narrowed or pressed together. This narrowing may occur in a particular place or may run along a larger section of the aorta.

Most often, the aorta is narrowed just beyond the left subclavian artery, which branches off just after the aorta leaves the heart to transport blood to the left arm. As a result of this narrowing, blood flow to the lower body tends to be reduced, which can lead to low blood pressure (hypotension) in the lower body and legs. In addition, blood flow to the upper body tends to be increased, which raises blood pressure in the upper body and forces the heart to work harder.

Coarctation of the aorta is a deceptively complex defect. While it may appear to be only a narrowed portion of the aorta, in fact the aortic anomaly is often one of many problems related to underdevelopment of the left side of the heart. For instance, patients with coarctation of the aorta have a significant chance of having abnormalities in the bicuspid valve (also known as the mitral valve), which rests between the left atrium and left ventricle. Other ventricular problems, including an undersized aortic arch, are also common. Alternatively, some patients may have a simple or mild coarctation that may not be immediately diagnosed.

Coarctation is a potentially dangerous condition because the aorta is the main artery that carries oxygen-rich blood from the heart to the rest of the body. When any part of this vital artery is narrowed, it can lead to fatal consequences. For example, severe coarctation of the aorta may result in heart failure if the heart is not strong enough to pump blood through the narrow opening. Patients who do not undergo surgery for this condition are unlikely to reach the age of 40.

Potential complications can include the following:

• High blood pressure (hypertension).
  
  
• Enlarged heart.
  
  
• Progressive kidney failure.
  
  
• Premature development of coronary artery disease (hardening and narrowing of the coronary arteries).
  
  
• Aortic aneurysm, which could lead to a potentially fatal aortic rupture if the aneurysm bursts.
  
  
• Aortic dissection. A tear in the inner lining of the aorta, creating a space between the inner and outer layers. If blood leaks into that space, a variety of potentially fatal conditions could result, including heart attack or stroke.
  
  
• Bleeding in the brain (intracerebral hemorrhage) or stroke.

Coarctation of the aorta is one of the top five heart defects that occurs at birth, accounting for 6 to 8 percent of all congenital defects. It occurs in approximately 1 out of every 10,000 people and is significantly more common among boys than girls. Furthermore, it has been linked to a genetic disorder in women (Turner syndrome) where one of the two X-chromosomes normally present in women is partially or totally absent. The condition is usually diagnosed in children or adults under 40 years of age.