Coarctation of the aorta
Coarctation of the aorta is a congenital (present at birth) heart defect involving a narrowing of the aorta. The aorta is the large artery that carries oxygen-rich (red) blood from the left ventricle to the body. It is shaped like a candy cane, with the first section moving up towards the head (ascending aorta), then curving in a C-shape as smaller arteries that are attached to it carry blood to the head and arms (aortic arch). After the curve, the aorta becomes straight again, and moves downward towards the abdomen, carrying blood to the lower part of the body (descending aorta).
The narrowed segment called coarctation can occur anywhere in the aorta, but is most likely to happen in the segment just after the aortic arch. This narrowing restricts the amount of oxygen-rich (red) blood that can travel to the lower part of the body. Varying degrees of narrowing can occur.
The more severe the narrowing, the more symptomatic a child will be, and the earlier the problem will be noticed. In some cases, coarctation is noted in infancy. In others, however, it may not be noted until school-age or adolescence.
Seventy-five percent of children with coarctation of the aorta also have a bicuspid aortic valve - a valve that has two leaflets instead of the usual three.
Coarctation of the aorta occurs in about 6 to 8 percent of all children with congenital heart disease. Boys have the defect twice as often as girls do.
What causes coarctation of the aorta?
Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality, or environmental exposure, causing heart problems to occur more often in certain families. Most of the time this heart defect occurs sporadically (by chance), with no clear reason for its development.
Why is coarctation a concern?
Coarctation of the aorta causes several problems, including the following:
- The left ventricle has to work harder to try to move blood through the narrowing in the aorta. Eventually, the left ventricle is no longer able to handle the extra workload, and it fails to pump blood to the body efficiently.
- Blood pressure is higher above the narrowing, and lower below the narrowing. Older children may have headaches from too much pressure in the vessels in the head, or cramps in the legs or abdomen from too little blood flow in that region. Also, the kidneys may not make enough urine since they require a certain amount of blood flow and a certain blood pressure to perform this task.
- The walls of the ascending aorta, the aortic arch, or any of the arteries in the head and arms may become weakened by high pressure. Spontaneous tears in any of these arteries can occur, which can cause a stroke or uncontrollable bleeding.
- There is a higher than average chance of developing an infection in the lining of the heart or aorta known as bacterial endocarditis.
- The coronary arteries, which supply oxygen-rich (red) blood to the heart muscle, may narrow in response to elevated pressure.
What are the symptoms of coarctation of the aorta?
Symptoms noted in early infancy are caused by moderate to severe aortic narrowing. The following are the most common symptoms of coarctation of the aorta. However, each child may experience symptoms differently. Symptoms may include:
- Pale skin
- Heavy and/or rapid breathing
- Poor feeding
- Poor weight gain
Mild narrowing may not cause symptoms at all. Often, a school-aged child or adolescent is simply noted to have high blood pressure or a heart murmur on a physical examination. Some may complain of headaches or cramps in the lower sections of the body.
The symptoms of coarctation of the aorta may resemble other medical conditions or heart problems. Always consult your child's physician for a diagnosis.
How is coarctation of the aorta diagnosed?
Your child's physician may have heard a heart murmur during a physical examination, and referred your child to a pediatric cardiologist for a diagnosis. A heart murmur is simply a noise caused by the turbulence of blood flowing through the obstruction from the right ventricle to the pulmonary artery. Symptoms your child exhibits will also help with the diagnosis.
A pediatric cardiologist specializes in the diagnosis and medical management of congenital heart defects, as well as heart problems that may develop later in childhood. The cardiologist will perform a physical examination, listening to your child's heart and lungs, and make other observations that help in the diagnosis. The location within the chest that the murmur is heard best, as well as the loudness and quality of the murmur (harsh, blowing, etc.) will give the cardiologist an initial idea of which heart problem your child may have. However, other tests are needed to help with the diagnosis, and may include the following:
- Chest x-ray - diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- Electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
- Echocardiogram (echo) - a procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
- Magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within the body.
Treatment for coarctation of the aorta
Specific treatment for coarctation of the aorta will be determined by your child's physician based on:
- Your child's age, overall health, and medical history
- Extent of the disease
- Your child's tolerance for specific medications, procedures, or therapies
- Expectations for the course of the defect
- Your opinion or preference
Coarctation of the aorta is treated with repair of the narrowed vessel. Several options are currently available.
Your child's coarctation of the aorta may be repaired surgically in an operating room or by a cardiac catheterization procedure. The surgical repair is performed under general anesthesia. The narrowed area is either surgically removed, or made larger with the help of surrounding structures or a patch.
The cardiac catheterization procedure may also be an option for treatment. During the procedure, the child is sedated and a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin and guided to the inside of the heart. Once the catheter is in the heart, the cardiologist will pass an inflated balloon through the narrowed section of the aorta to stretch the area open. A small device, called a stent, may also be placed in the narrowed area after the balloon dilation to keep the aorta open.
Some infants will be very sick, requiring care in the intensive care unit (ICU) prior to the procedure, and could possibly even need emergency repair of the coarctation. Others, who are exhibiting few symptoms, will have the repair scheduled on a less urgent basis.
After surgery, infants will return to the intensive care unit (ICU) to be closely monitored during recovery.
While your child is in the ICU, special equipment will be used to help him/her recover, and may include the following:
- Ventilator - a machine that helps your child breathe while he/she is under anesthesia during the operation. A small, plastic tube is guided into the windpipe and attached to the ventilator, which breathes for your child while he/she is too sleepy to breathe effectively on his/her own. Many children remain on the ventilator for a while after surgery so they can rest.
- Intravenous (IV) catheters - small, plastic tubes inserted through the skin into blood vessels to provide IV fluids and important medicines that help your child recover from the operation.
- Arterial line - a specialized IV placed in the wrist, or other area of the body where a pulse can be felt, that measures blood pressure continuously during surgery and while your child is in the ICU.
- Nasogastric (NG) tube - a small, flexible tube that keeps the stomach drained of acid and gas bubbles that may build up during surgery.
- Urinary catheter - a small, flexible tube that allows urine to drain out of the bladder and accurately measures how much urine the body makes, which helps determine how well the heart is functioning. After surgery, the heart will be a little weaker than it was before, and, therefore, the body may start to hold onto fluid, causing swelling and puffiness. Diuretics may be given to help the kidneys to remove excess fluid from the body.
- Chest tube - a drainage tube will be inserted to keep the chest free of blood that would otherwise accumulate after the incision is closed. Bleeding may occur for several hours, or even a few days after surgery.
- Heart monitor - a machine that constantly displays a picture of your child's heart rhythm, and monitors heart rate, arterial blood pressure, and other values.
Your child may need other equipment not mentioned here to provide support while in the ICU, or afterwards. The hospital staff will explain all of the necessary equipment to you.
Your child will be kept as comfortable as possible with several different medications; some which relieve pain, and some which relieve anxiety. The staff will also be asking for your input as to how best to soothe and comfort your child.
After being discharged from the ICU, your child will recuperate on another hospital unit for a few days before going home. You will learn how to care for your child at home before your child is discharged. Your child may need to take medications for a while, and these will be explained to you. The staff will give you instructions regarding medications, activity limitations, and follow-up appointments before your child is discharged.
Long-term outlook after coarctation of the aorta surgical repair
Most children who have had a coarctation of the aorta surgical repair will live healthy lives. Activity levels, appetite, and growth should eventually return to normal.
As the child grows, the aorta may once again become narrow on occasion. If this happens, a balloon procedure or operation may be necessary to repair the coarctation.
Your child's cardiologist may recommend that antibiotics be given to prevent bacterial endocarditis after discharge from the hospital.
Consult your child's physician regarding the specific outlook for your child.