Coarctation of the aorta is a type of congenital heart disease. There is a narrowing in part of the aorta, the main artery that leaves the left side of the heart. The degree of narrowing can vary from person to person. In severe coarctation of the aorta, symptoms usually appear within the first few weeks of life. Coarctation of the aorta is sometimes detected later on in childhood, and occasionally during adulthood. Surgery may be carried out to repair the narrowed part of the aorta. Sometimes a balloon can be inserted into the aorta to open up the narrowing.
Some anatomy of the normal heart and main blood vessels
The heart is a fist-sized organ which lies within the chest behind the breastbone (sternum). It is a muscular pump that pushes blood through blood vessels around the body. The heart sits on the diaphragm, the main muscle of breathing, which is found beneath the lungs. The heart is considered to have two sides - the right side and the left side.
The heart has four chambers - an atrium and ventricle on each side. The two atria are separated by a wall called the atrial septum. The two ventricles are separated by a wall called the ventricular septum. The atria are both supplied by large blood vessels that bring blood to the heart.
Atria have special valves that open into the ventricles. The valve that opens from the right atrium into the right ventricle is called the tricuspid valve. The valve that opens from the left atrium into the left ventricle is called the mitral valve. The ventricles also have valves but in this case they open into blood vessels. The pulmonary valve opens from the right ventricle into the pulmonary artery. The aortic valve opens from the left ventricle into the aorta. The walls of the heart chambers are made mainly of special heart muscle. The different sections of the heart have to squeeze (contract) in the correct order for the heart to pump blood efficiently with each heartbeat.
The heart's main function is to pump blood around the body.
The right side of the heart receives deoxygenated blood (lacking oxygen) from the body. After passing through the right atrium and right ventricle, this blood is pumped through the pulmonary valve and into the pulmonary artery to the lungs. Here blood picks up oxygen and loses another gas called carbon dioxide. Once through the lungs, the blood flows back to the left atrium. It then passes into the left ventricle and gets pumped through the aortic valve into the aorta, the main artery supplying the body. Oxygenated blood is then carried though blood vessels to all the body's tissues. Here oxygen and other nutrients pass into the cells where they are used to perform the body's essential functions.
For more information about how the heart and blood vessels work, please see separate leaflet called The Heart and Blood Vessels.
What is coarctation of the aorta?
Coarctation of the aorta is a type of congenital heart disease. (A congenital condition is a condition that you are born with.) There are a number of different types of congenital heart disease. Coarctation of the aorta is just one type.
As mentioned above, the aorta is the main artery that leaves the left side of the heart (the left ventricle) and supplies oxygen-rich (oxygenated) blood to the body. The aorta is the main artery of the body and all of the other arteries of the body derive from it. After it leaves the heart, other arteries branch off from the aorta and supply blood to the head and arms. However, the main aorta continues on through the chest, into the tummy (abdomen), and supplies blood to the lower half of the body and legs.
In coarctation of the aorta, there is a narrowing in part of the aorta, usually the upper part of the aorta. This is just after where the arteries that supply blood to the head and arms have branched off. Blood cannot pass as easily through the narrowed part of the aorta. This means that the blood supply to the lower half of the body can be affected (less blood is able to get through). Also, because of the narrowing, the heart works harder to pump and try to squeeze blood through the narrowing. Because the heart is working harder to pump, this can cause blood pressure to rise. Often, someone with coarctation of the aorta will have high blood pressure in their upper body and arms (or one arm) and low blood pressure in their lower body and legs. Also, the muscle walls of the left ventricle can increase in thickness (hypertrophy) because of the extra work that they are having to do.
The degree of narrowing in coarctation of the aorta can be different in different people. Some babies will be born with severe narrowing which can lead to symptoms soon after they are born (see below). However, in others, the narrowing is less severe and symptoms may not be noticed until later. In some people, the narrowing may gradually get worse over time and therefore lead to symptoms. Occasionally, coarctation of the aorta does not cause any symptoms or is not detected until adult life.
When a baby is growing inside their mother's womb, the pulmonary artery and the aorta are joined together by a small blood vessel called the ductus arteriosus. It means that most of the blood leaving the right ventricle bypasses the lungs and passes directly into the aorta. Once the baby is born, the ductus arteriosus closes, usually within the first few weeks of life. If a baby has severe coarctation of the aorta, the only way that blood can pass to the lower half of the body is through the ductus arteriosus. So, when the ductus arteriosus closes in these babies, no blood will get through to the lower half of the body, causing severe symptoms. If nothing is done about this, the baby can die.
What causes coarctation of the aorta?
Coarctation of the aorta happens because of a problem with the development of the baby's aorta whilst they are growing inside their mother's womb. In most cases, it is not known why this problem happens.
Coarctation of the aorta can occur alone, or it can occur with other congenital heart problems. The other congenital heart problems that coarctation of the aorta most commonly occurs with are either:
- A bicuspid aortic valve (the aortic valve is normally made up of three cusps or flaps, a bicuspid aortic valve only has two cusps); or
- A ventricular septal defect (a condition where there is a hole in the wall - the septum - that separates the two ventricles).
In some babies, coarctation of the aorta can develop as part of a syndrome (a collection of symptoms) that a baby is born with. For example, coarctation of the aorta can be part of Turner syndrome. (This is a genetic condition that only affects girls. It is a chromosome problem. The most characteristic features of the syndrome are being short, having certain physical features, such as a typical facial appearance, and also having ovaries that do not work properly.)
How common is coarctation of the aorta?
In about 7 in 1,000 pregnancies, the developing baby will have congenital heart disease. Coarctation of the aorta is just one type of congenital heart disease. Around 1 in 2,500 babies have coarctation of the aorta. The condition is twice as common in males as it is in females.
What are the symptoms of coarctation of the aorta?
As mentioned above, the degree of narrowing in coarctation of the aorta can vary from person to person.
If the narrowing is severe, symptoms will usually become obvious within the first few weeks of life (as the ductus arteriosus closes). The baby may not be feeding well, may not be putting on weight and may become tired easily. They can become very unwell and can develop heart failure because their heart is not able to push blood through the narrowed part of the aorta. This causes a back-pressure of blood and congestion of the lungs, leading to symptoms including shortness of breath.
If the narrowing is less severe, symptoms may not become obvious until later in childhood (and sometimes even adulthood). This is because the body develops extra blood vessels, called collateral blood vessels, so that some blood is able to bypass the narrowed part of the aorta. These collateral blood vessels may be enough for some time but, eventually, the heart is no longer able to cope and symptoms of heart failure start to appear. These include shortness of breath, coughing, feeling tired and swelling of the feet and legs.
Sometimes, coarctation of the aorta may be suspected before any symptoms have developed. For example, during a routine check in a baby or child, the doctor may hear a heart murmur when they listen to the child's heart. This is a noise that the doctor hears through their stethoscope. It is due to the turbulent flow of blood through the narrowed part of the aorta. Or, a child may be found to have high blood pressure during a routine check. In coarctation of the aorta, the blood pressure in the arms can be high and higher than that in the legs. The doctor may also feel a difference when checking the pulses in the child's arms and the legs. Because of the narrowing, less blood gets through to the legs and lower part of the body. This means that the pulses in the legs can feel weaker.
How is coarctation of the aorta diagnosed?
If a doctor suspects coarctation of the aorta because of symptoms or a heart murmur, blood pressure or pulse problems, they will usually suggest some investigations to confirm the diagnosis. These may include:
- Echocardiogram - this is an ultrasound scan of the heart and will usually show up the narrowing in the aorta. It may also be possible to measure the differences in pressure on either side of the narrowing (called the pressure gradient) and so give an idea of how severe the narrowing is.
- Chest X-ray - this may show that the heart is enlarged. It may show fluid on the lungs if there is heart failure. It may also show some 'notching' (or grooves) on the ribs if collateral blood vessels have developed.
- Electrocardiogram (ECG) - this is a test that records the electrical activity of the heart. It can be abnormal in some people with coarctation of the aorta.
- Magnetic resonance imaging (MRI) - scanning of the blood vessel using magnetic rays.
- Cardiac catheterisation - a catheter is a thin, flexible, hollow tube. Cardiac catheterisation entails a very thin plastic catheter being passed into the chambers of the heart. The catheter can also be passed into the main blood vessels of the heart (the coronary arteries). It is sometimes carried out if someone has coarctation of the aorta. The difference in pressure on either side of the narrowing can be measured to look at how severe the coarctation is. See separate leaflet called Cardiac Catheterisation for more details.
Occasionally, coarctation of the aorta may be detected when a woman is having her routine ultrasound scans during pregnancy. The abnormally narrowed aorta may be seen when looking at her baby's heart. However, coarctation of the aorta can be very difficult to detect in this way.
What is the treatment for coarctation of the aorta?
Treatment to help stabilise symptoms
If a newborn baby has severe coarctation of the aorta, they will first need to have treatment to help control their symptoms. This may include medicines to help treat any heart failure and sometimes they may need to have artificial ventilation to help with their breathing. They may also be given a special medicine that can help to keep the ductus arteriosus open so that blood can pass to the lower part of their body (below the narrowed aorta).
If a child has developed high blood pressure because of coarctation of the aorta, this may need treatment with medicines.
Treatment for the narrowed aorta
The narrowing of the aorta can be repaired using surgery. The surgeon will need to open up the chest so that they can get access to the heart and aorta to operate on them. A clamp is placed across the aorta to stop the flow of blood through it. Then, the narrowed section is cut out and the two normal-sized parts of the aorta are joined back together. Sometimes, if a large part of the aorta has to be removed due to narrowing, a patch (or graft) of special synthetic material is used to fill the gap and repair the aorta.
A newer way of treating coarctation of the aorta is by using balloon angioplasty. This may be used in older children and adults who have been diagnosed with the condition. A balloon catheter (a thin, flexible, hollow tube with a deflated balloon at the tip) is inserted into a large blood vessel, usually an artery in the groin. X-ray guidance is then used and the catheter is passed up through the blood vessels within the body until it reaches the narrowed part of the aorta. The balloon is then inflated within the narrowed section, making the narrowing wider. Sometimes, a small, expandable metal tube (a stent) is then placed in the narrowed segment to keep it open.
Are there any complications?
If treated, the outlook (prognosis) for coarctation of the aorta is usually good. However, there are some complications that may develop in some people. These may be complications related to the surgery to repair the narrowing, or other complications.
Complications from the surgery
Anyone who has had surgery for coarctation of the aorta will need regular check-ups with a specialist afterwards. Many will have no serious complications due to the surgery and will go on to lead healthy lives afterwards. However, sometimes complications can develop, either at the time of surgery or shortly afterwards. These may include:
- Internal bleeding during the surgery.
- Infection of the wound after the surgery.
- Damage to the kidneys during the surgery.
- Damage to the spinal cord because of the surgery. This is more likely if the operation is more complicated and the aorta needs to be clamped for a longer period of time. (Because the aorta is clamped, it can stop blood getting through to the spinal cord.) If the spinal cord is damaged, this can mean that the child's legs can become permanently paralysed. This complication is rare, but obviously can be very serious.
- A stroke due to the surgery. However, this is also very rare.
Some other complications are also possible over time after surgery. They can include:
- Return of the narrowing of the aorta. This is known as recurrent coarctation.
- An aortic aneurysm. This is a widening, or dilatation, of the aorta. An aortic aneurysm can be a complication of coarctation of the aorta that has not been treated with surgery but it is also a rare complication after surgery. The widened part of the aorta is weaker and there is a risk that it can burst (rupture), causing severe internal bleeding.
- Persisting high blood pressure despite the fact that the narrowed part of the aorta has been widened or is no longer present. This may need treatment with medication.
Anyone with coarctation of the aorta (whether they have had surgery or not) has a small risk of getting infective endocarditis. This is an infection that affects part of the tissue that lines the inside of the heart chambers (the endocardium). The infection usually involves one or more heart valves which are part of the endocardium. Infective endocarditis is rare but it is a serious infection that can be life-threatening if it is not detected and treated. A separate leaflet called Infective Endocarditis gives more details.
About 4 in 100 people who have coarctation of the aorta also have an aneurysm of one of the small blood vessels in their brain, called a berry aneurysm. As mentioned above, an aneurysm is an abnormally widened, or dilated, part of a blood vessel. The widened part tends to be weaker and there is a risk that it may burst. If a berry aneurysm in the brain bursts, this can lead to bleeding in the brain and a subarachnoid haemorrhage. However, not all berry aneurysms will burst. Symptoms of a subarachnoid haemorrhage can include:
- A severe headache (often described as feeling like someone has hit you across the back of the head).
- Being sick (vomiting).
- Vision problems.
- A seizure (convulsion).
A number of women who have had treatment for coarctation of the aorta go on to have a normal pregnancy with no problems. However, if a woman has coarctation of the aorta, or has had treatment for it, and she is planning to become pregnant, she should discuss this with her heart specialist first. This is because pregnancy can put an extra strain on the heart. It is best to plan a pregnancy when a woman's symptoms and heart condition are stable.
Also, if someone has been born with congenital heart disease, it is more likely that they will have a baby who is also born with congenital heart disease. This risk should be discussed with a heart specialist. It may be possible to arrange for scans of the baby's heart early on in the pregnancy to look for any heart problems.
Dr Michelle Wright
Dr Gurvinder Rull
Dr John Cox