Coarctation of the aorta is a congenital heart defect where a section of the aorta, the body’s largest artery, is abnormally narrow. This narrowing forces the heart to pump harder to push blood through the tight spot, raising blood pressure above the narrowing while reducing blood flow below it. It accounts for a small but significant percentage of congenital heart defects and can range from mild (sometimes undetected into adulthood) to severe enough to cause life-threatening problems in newborns.
Where the Narrowing Occurs
The aorta arches up from the heart and curves downward through the chest, sending branches to the head, arms, and eventually the rest of the body. The narrowing in coarctation almost always occurs in the upper chest, just past where the artery branches off to the left arm. This places it near a small structure called the ductus arteriosus, a blood vessel that is open during fetal development and normally closes shortly after birth.
Older medical textbooks describe “preductal” and “postductal” types based on whether the narrowing sits before or after this duct. But closer study of the anatomy shows that virtually all coarctations sit right at the level of the duct, making this distinction less meaningful than once thought. In rare cases, the narrowing can occur lower in the chest or even in the abdominal portion of the aorta.
What It Does to Blood Flow
Think of a garden hose with a kink. Pressure builds up before the kink, and flow drops after it. In coarctation, this means the upper body (head, arms) receives blood at higher-than-normal pressure, while the lower body (legs, kidneys, abdominal organs) gets blood at lower pressure and reduced volume. The left ventricle, the heart’s main pumping chamber, has to work significantly harder to force blood through the narrowed segment. Over time, this extra workload causes the heart muscle to thicken, a condition that can lead to heart failure if left untreated.
The body does try to compensate. Smaller blood vessels around the chest wall, ribs, and shoulder blades gradually enlarge to create detour routes around the blockage. These collateral vessels can supply some blood to the lower body, which is why some people with moderate coarctation survive into adulthood before the condition is caught.
Symptoms in Infants
Severe coarctation typically shows up within the first days or weeks of life, often when the ductus arteriosus closes naturally after birth. Once that backup route shuts down, the baby’s lower body suddenly loses much of its blood supply. Signs include irritability, poor feeding, rapid or heavy breathing, changes in skin color (pale or grayish), and cold feet or legs. These babies can deteriorate quickly and need urgent treatment.
Symptoms in Older Children and Adults
Milder coarctation can go undetected for years. Adults and older children with a less severe narrowing may not have obvious symptoms at all, and their hearts may appear healthy on initial evaluation. When symptoms do appear, they tend to reflect the high blood pressure in the upper body and reduced flow to the lower body: headaches, chest pain, muscle weakness or leg cramps during exercise, nosebleeds, and cold feet. High blood pressure that shows up at a young age, especially when it’s hard to control with medication, is one of the most common clues that coarctation may be present.
How It Is Diagnosed
The hallmark finding is a blood pressure difference between the arms and legs. Normally, blood pressure in the legs is slightly higher than in the arms. In coarctation, it’s the reverse. A pressure gradient of 20 mmHg or more between the upper and lower extremities, combined with imaging that confirms anatomic narrowing, is a standard indication that the coarctation needs treatment. Even a gradient of 10 mmHg or more can be significant if the heart is already showing signs of strain.
Echocardiography (an ultrasound of the heart) is usually the first imaging test. It can show the narrowed segment, estimate the pressure difference across it, and assess how well the heart is functioning. For a more detailed picture, cardiac MRI is considered the gold standard. MRI can map the exact anatomy, measure blood flow volumes above and below the narrowing, and quantify how much blood is rerouting through collateral vessels. Studies show that combining the structural and flow data from MRI yields roughly 95% sensitivity and 82% specificity for detecting coarctation. CT scans can also provide detailed images but involve radiation exposure, so MRI is generally preferred when available.
Treatment Options
Coarctation does not resolve on its own. Treatment involves either open surgery or a catheter-based procedure, depending on the patient’s age, the severity of the narrowing, and the anatomy involved.
Surgical Repair
Surgery has been performed for coarctation since 1945 and remains the standard approach for newborns and young infants. The most common technique involves removing the narrowed segment entirely and stitching the two healthy ends of the aorta back together. This avoids the need for any artificial material and preserves the blood supply to the left arm. Surgeons use interrupted, absorbable stitches so the repair site can grow along with the child, reducing the risk of the area narrowing again later.
Other surgical approaches exist for situations where a simple reconnection isn’t feasible. One technique uses tissue from a nearby artery to widen the narrowed area, which works well for longer segments of narrowing but sacrifices a major artery to the left arm. Another uses a patch of synthetic material to enlarge the tight spot, which preserves surrounding arteries but carries a small long-term risk of the patched area ballooning out into an aneurysm.
Catheter-Based Treatment
For older children (generally weighing more than about 10 kg, or 22 pounds) and adults, balloon angioplasty or stent placement through a catheter is an alternative to open surgery. A thin tube is threaded through a blood vessel in the groin up to the narrowed section, where a balloon is inflated to widen it. A metal stent can be left in place to hold the artery open. This approach avoids a chest incision and has a shorter recovery time. It is especially useful for treating re-narrowing after a previous surgical repair.
Long-Term Outlook After Repair
Repair eliminates the immediate problem, but coarctation is a lifelong condition that requires ongoing monitoring. About 10% of patients need a second procedure on the same area within 30 years of their initial repair, with freedom from re-intervention rates of roughly 97% at 10 years, 92% at 20 years, and 89% at 30 years.
The most common long-term issue is persistent or recurrent high blood pressure. Even after successful repair, many patients develop hypertension later in life. Age at repair matters significantly: children who have surgery before age 9 have substantially lower rates of high blood pressure in the following 5 to 15 years compared to those repaired later. This is one reason early detection and treatment are so important.
Brain Aneurysm Risk
One lesser-known but important concern is an elevated risk of brain aneurysms. By middle age, 10% to 13% of people with coarctation have an intracranial aneurysm detectable on screening, compared to 3% to 7% in the general population. These aneurysms are typically small and cause no symptoms, but a rupture can be catastrophic. The American Heart Association and American College of Cardiology recommend screening for brain aneurysms in people with a history of coarctation, with research suggesting that screening at ages 10, 20, and 30 is both effective and cost-effective at extending life.
Associated Heart Defects
Coarctation rarely occurs in complete isolation. It is frequently found alongside other structural heart problems. The most common is a bicuspid aortic valve, where the valve controlling blood flow out of the heart has two flaps instead of the normal three. Other associated defects include holes between the heart’s chambers and abnormalities of the mitral valve. These associated conditions can influence both the timing of treatment and the long-term follow-up plan, which is why comprehensive heart imaging at diagnosis is essential.