The aorta, the main artery carrying blood from the heart to the body, is pinched or constricted. This obstructs blood flow to the lower part of the body and increases blood pressure above the constriction. Usually there are no symptoms at birth, but they can develop as early as the first week after birth. A baby may develop congestive heart failure or high blood pressure that requires early surgery. Otherwise, surgery usually can be delayed. A child with a severe coarctation should have surgery in early childhood. This prevents problems such as developing high blood pressure as an adult.

The outlook after surgery is favourable, but long-term follow-up is required. Rarely, coarctation of the aorta may recur. Some of these cases can be treated by balloon angioplasty. The long-term results of this procedure are still being studied. Also, blood pressure may stay high even when the aorta's narrowing has been repaired.

People with coarctation of the aorta, before and after treatment, are at risk for getting an infection within the aorta or the heart valves (endocarditis). To help prevent this, they'll need to take antibiotics before certain dental and surgical procedures.