Coarctation of the Aorta
Coarctation of the aorta is a discrete narrowing of the aorta, the main blood vessel carrying oxygen-rich blood from the heart to the body, causing an obstruction to blood flow. Coarctation is a common congenital heart defect, an abnormality in the structure of the aorta that is present at birth or shortly after birth. It may be identified in infants or older children or adults and successfully repaired at any age. Treatment options to relieve the aortic obstruction include surgery and cardiac catheterization procedures.
How Does Coarctation Affect the Circulation?
Blood leaves the heart through the aortic valve to the aorta, which gives off branches to the head and arms in an area called the aortic arch. The aorta then turns downward (descending aorta) to carry blood to the lower body. Typical coarctation occurs in the descending part of the aorta beyond the aortic arch (see Figure) The obstruction makes it hard for the blood to get beyond the narrowed area. The blood pressure before the obstruction is high, and the blood pressure beyond the obstruction is abnormally low. If the aortic narrowing is severe, the left ventricle (main pumping chamber in the heart) may not be able to pump against the very high pressure and begin to fail. This presentation occurs in some newborns; it is rare in older children.
Other Abnormalities of the Heart Seen With Coarctation
In association with coarctation, the aortic arch, the area between the ascending aorta and the descending aorta, may be smaller than normal (hypoplastic), particularly in newborns. Over time, extra blood vessels called collaterals develop to carry blood around the area of obstruction. Most patients with coarctation have a bicuspid aortic valve, meaning the aortic valve, located between the left ventricle and the aorta, has 2 leaflets instead of the normal 3. Other cardiac defects can occur with coarctation, including abnormalities on the left side of the heart or more complex defects. This discussion will focus on the presentation, diagnosis, and treatment options for coarctation, not the other associated congenital heart defects.
Coarctation and other abnormalities on the left side of the heart occur more often in boys than girls. These obstructions in the left side of the heart can run in families, and a genetic tendency is likely. When coarctation occurs in girls, it can be associated with Turner syndrome, a chromosomal abnormality with other related abnormal findings.
How Is Coarctation Identified?
The presenting signs of coarctation vary with age.
Patients with severe narrowing present in the newborn period. In the first weeks of life, infants may become sick quickly over a few days. The heart is pumping against high pressure that may cause it to pump poorly. The blood pressure in the upper body is high and in the lower body is very low. Infants appear pale, have trouble breathing, have difficulty feeding, and may be very fussy or very weak. The symptoms can quickly progress to shock and require admission to an intensive care unit with medications to support the circulation until an intervention to relieve the obstruction can be performed.
Most often, children, adolescents, and adults have no symptoms and coarctation is identified when a heart murmur (abnormal heart sounds attributable to turbulent blood flow) is heard with a stethoscope or during an evaluation for causes of hypertension (high blood pressure). Some patients may report chest pain, headaches, leg pains, and cramps with exercise or decreased exercise ability.
There are 2 signs of coarctation on physical examination:
High blood pressure in the arms and low blood pressure in the legs. The blood pressure is higher in the vessels before the obstruction, in this case, in the arms, and lower in the area beyond the obstruction. The difference in pressure between the arms and the legs is called a gradient.
The quality of the pulses in the arms and the legs is also different, with bounding pulses in the arms and weak or absent pulses in the legs.
If these signs are identified, patients are referred to a cardiologist for further evaluation. An ECG and a chest x-ray may have findings that suggest a coarctation. The definitive test is an echocardiogram, an ultrasound test that provides images of the heart and aorta and identifies the area of obstruction. Echocardiogram images are usually sufficient to plan surgery for young infants. An MRI is an imaging study done inside a magnet that allows very detailed images of the heart, aorta, and collateral blood vessels. The study requires patients to lie still in an enclosed space for up to an hour, and younger children may need anesthesia for a successful study.
The choice of treatment depends on a number of factors, including the age of the patient, the anatomy of the aortic obstruction, and the risks and benefits of the procedures.
Surgical repair is the traditional and most time-tested treatment for most patients, particularly infants and younger children (see Table), The procedure is done through an incision in the left side of the chest and does not require the heart-lung machine. The hospital stay is usually 4 to 7 days following surgery with the first few days in an intensive care unit. High blood pressure is common after surgery and is managed with intravenous (into the bloodstream) medicines, and then medications taken by mouth that usually continue after they leave the hospital. The risks of the procedure are very low, and the outcomes are excellent.
Cardiac catheterization is a test done by using catheters (small tubes) placed into the peripheral (in the arm or leg) blood vessels and maneuvered into the large vessels and the heart. In the past 25 years, a number of procedures using special catheters have been developed to repair the heart. The narrowing of the aorta found in coarctation can be opened up from the inside using balloon dilation or by placing a stent (see Table).
The catheterization procedure takes several hours and is done under anesthesia. Patients are observed overnight in the hospital and can resume normal activities within a few days of the procedure. If stents are placed, aspirin is taken for a number of months to prevent blood clots. Precautions to prevent infection are also needed. Antibiotics are given before dental work and some other medical procedures (this is called bacterial endocarditis prophylaxis).
Following successful treatment, patients with coarctation of the aorta are able to lead a normal lifestyle and likely have a near-normal lifespan. Limited exercise restrictions may be indicated for patients with high blood pressure, continued aortic obstruction, or dilation of the aorta. Lifelong regular cardiology evaluations with imaging of the heart are important to monitor for later problems. High blood pressure is common in patients with coarctation as they get older, even after a successful repair, and they need long-term antihypertensive medications. This is more likely when repair is done in older children or adults. High blood pressure leads to thickening of the heart muscle, changes in blood vessels, and increases the risk of stroke, kidney damage, coronary artery disease, and other health problems. Maintaining normal blood pressure is important for future health. The repaired area of the aorta may become narrowed again (called recoarctation) with the return of a blood pressure difference between the arms and legs on physical examination and evidence of aortic obstruction by echocardiogram or MRI. Recoarctation is more common when the repair is done in infancy. Balloon angioplasty is the typical treatment option for recoarctation, although repeat surgery may be indicated for some patients. Aneurysms (weakness in the wall of the aorta) can occur at the site of the repair after surgery or catheterization, although the significance of these is unclear. The bicuspid aortic valve, often associated with coarctation of the aorta, may develop narrowing (stenosis) or leaking (regurgitation) over time and need treatment.
Coarctation of the aorta is a narrowing of the aorta that can be successfully treated with surgery or catheterization techniques. The choice of treatment depends on the age of the patient, the anatomy of the area of obstruction, and other factors. Both procedures provide successful relief of the obstruction for most patients at low risk. High blood pressure, recoarctation, and aortic aneurysms are possible after repair, so lifelong cardiac evaluations are important. New materials and techniques are being explored to improve the treatment of coarctation in the future.
Adult Congenital Heart Association Website: http://www.achaheart.org
American Heart Association Website: http://www.heart.org
Boston Children’s Hospital Website: http://www.childrenshospital.org
The information contained in this Circulation Cardiology Patient Page is not a substitute for medical advice, and the American Heart Association recommends consultation with your doctor or healthcare professional.
- © 2015 American Heart Association, Inc.