Patients without severe obstruction and the development of abundant collaterals can go undetected until later childhood or adulthood, when a murmur and/or a difference in blood pressure between the upper and lower body may be observed. Upper body hypertension will usually be present to some degree, often with low pressure in the lower body. This is caused by the constriction in the aorta, which retards the flow of blood to the lower body tissues.

Adults with coarctation of the aorta may have a variety of symptoms, varying from a heart murmur and divergent upper and lower body blood pressures to uniform blood pressure with an aneurysm at the site of the coarctation. Also, a delayed pulse in the lower body may be observed. Approximately 7 out of 10 people with this defect will have a bicuspid aortic valve, with only two leaflets rather than the usual three. This may also contribute to the obstruction of blood flow through the aorta.

The persistent upper body hypertension that often occurs with coarctation of the aorta may cause health problems over time, including the development of various forms of aortic stenosis, mitral valve dysfunction, enlargement of the left ventricle, and a tendency to aneurysm formation that may lead to stroke.

If there are symptoms suggestive of this defect, the patient will be examined through the use of electrocardiography (producing an ECG, or electrocardiogram), chest x-ray, MRI (Magnetic Resonance Imaging) and/or echocardiography (producing an echocardiogram). In some cases, a cardiac catheterization procedure may be necessary.

80% of untreated patients with coarctation of the aorta will not live beyond 50 years of age, so it is important that the patient be evaluated and treated. Most patients who require surgical treatment will have the narrowed part of the aorta removed and the adjoining sections of unrestricted vessel joined together. In select patients a non-surgical approach includes the insertion of a stent and widening the vessel by balloon angioplasty.

After treatment, the patient's prognosis is usually excellent. Medications may be needed to control high blood pressure, which often persists even after the coarctation has been repaired. The patient should receive regular checkups to monitor blood pressure and ensure that a recoarctation (when the aorta again becomes restricted from excessive scarring or poor growth of a repair in childhood) or other symptoms do not occur. A biscupid aortic valve if present is monitored for stenosis as well as associated dilation of the aorta distal to the aortic valve. Some patients can develop progression dilation of the aorta and require surgical repair.