 Aortic Stenosis
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Valves of the heart
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When a heart is functioning normally, blood is pumped through its four chambers with the help of a series of heart valves.
These valves open and close in a way that allows blood to flow only one way. The aortic valve allows oxygen-rich (red) blood to flow from the left pumping chamber of the heart, called the left ventricle, to the body's main artery, called the aorta. The aorta sends oxygen-rich blood throughout the body.
The aortic valve has three leaflets that function like a one-way door, allowing blood to flow forward into the aorta, but not backward into the left ventricle.
Aortic stenosis is the inability of the aortic valve to open completely. Aortic stenosis may be congenital (present at birth) or acquired (develop later in life).
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Aortic Stenosis
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With aortic stenosis, problems with the aortic valve make it harder for the leaflets to open and permit blood to flow forward from the left ventricle to the aorta.
In children, these problems can include a valve that:
- only has two leaflets instead of three (bicuspid aortic valve)
- has leaflets that are partially fused together
- has thick leaflets that do not open all the way
- becomes damaged by rheumatic fever or bacterial endocarditis
Aortic stenosis may be present in varying degrees, classified according to how much obstruction to blood flow is present. A child with severe aortic stenosis will be quite ill, with major symptoms noted early in life. A child with mild aortic stenosis may have few symptoms, or perhaps none until later in adulthood. The degree of obstruction can become worse with time.
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Congenital aortic stenosis occurs in 3 to 6 percent of all children with congenital heart disease. Relatively few children show sign of aortic stenosis in infancy, but the incidence of problems increases sharply in adulthood.
Congenital aortic stenosis occurs four times more often in boys than in girls.
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Congenital aortic stenosis occurs due to improper development of the aortic valve in the first 8 weeks of fetal growth. Most of the time, this heart defect occurs sporadically (by chance), with no apparent reason for its development.
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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.
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Acquired aortic stenosis may occur after a strep infection that progresses to rheumatic fever. Rheumatic fever is a disease that is now much less common in the United States than it was several decades ago. It is an inflammatory disease caused by certain rare forms of strep bacteria that can cause inflammation and scarring of the heart valves.
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Mild aortic stenosis may not cause any symptoms. However, there is a higher than average chance of developing an infection on the abnormal aortic valve known as bacterial endocarditis.
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Also, when aortic stenosis is moderate to severe, the left ventricle has to work harder to get blood through the tight aortic valve to the body. In response, the left ventricle becomes thicker and pumps blood at a higher pressure. Over time, this extra workload can cause damage to the left ventricle while it fails to pump blood to the body efficiently.
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The coronary arteries, which supply oxygen-rich (red) blood to the heart muscle, may not receive enough blood to meet the demands of the heart.
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In addition, regurgitation, which means leaking of blood backwards through the valve, is common in patients with aortic stenosis. Normally this would happen after interventions to help fix the obstruction of the valve have been done. When severe, this can complicate aortic stenosis and result in additional problems for the left ventricle.
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Most often, children with aortic stenosis have no symptoms. The following are common symptoms of aortic stenosis. Each child may experience symptoms differently. Symptoms may include:
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- fatigue
- dizziness with exertion
- shortness of breath
- irregular heartbeats or palpitations
- chest pain
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The symptoms of aortic stenosis may resemble other medical conditions or heart problems. Always consult your child's physician for a diagnosis.
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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, heard with a stethescope, caused by the turbulence of blood flowing through the obstruction from the left ventricle to the aorta. Symptoms your child may experience will also help with the diagnosis.
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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:
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- chest x-ray - a 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 stress."
- 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. This is a type of ultrasound."
- exercise electrocardiogram (ECG or EKG) - an exercise EKG is done to assess the heart's response to stress or exercise. The EKG is monitored while your child is exercising on a treadmill or stationary bike. An EKG measures the electrical activity of your child's heart."
- cardiac catheterization - a procedure that gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. Contrast dye is also injected to more clearly visualize the structures inside the heart."
- cardiac magnetic resonance imaging (MRI) - a non-invasive test that uses three-dimensional imaging technology produced by magnets to accurately determine blood flow and functioning of the heart as it is working."
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Specific treatment for aortic stenosis will be determined by your child's physician based on:
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- your child's age, overall health, and medical history
- extent of the disease
- your child's tolerance for specific medications, procedures, or therapies
- how your child's doctor expects the disease may progress
- your opinion or preference
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Aortic stenosis is treated with repair of the obstructed valve. Several options are currently available.
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Some infants will be very sick, require care in the intensive care unit (ICU) prior to the procedure, and could possibly even need emergency repair of the aortic stenosis. Others, who show few symptoms, will have the repair scheduled on a less urgent basis.
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Children who do not require immediate repair in infancy may need to receive antibiotics to prevent an infection of the inner surfaces of the heart and valves known as bacterial endocarditis prior to procedures such as a routine dental check-up and teeth cleaning. Other procedures may also increase the risk of the heart infection occurring. It is important that you inform all medical personnel that your child has aortic stenosis so they may determine if antibiotics are necessary prior to the procedure.
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Activity may be limited in children who have moderate aortic stenosis prior to repair. For instance, competitive sports that require endurance may be restricted.
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Repair options include the following:
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- balloon dilation - a cardiac catheterization procedure, a small, flexible tube (catheter) is inserted into a blood vessel in the groin, and guided to the inside of the heart. The tube has a deflated balloon in the tip. When the tube is placed across the narrowed valve, the balloon is inflated to stretch the area open.
- surgical repair - the treatment of aortic valve stenosis in most centers is now balloon dilation. If this is unsuccessful, i.e. the pressure gradient cannot be reduced or the pressure gradient is very much reduced but leakage of the valve is induced (regurgitation), it may be necessary to undertake surgical repair of the aortic valve. If this is not successful the valve must be replaced.
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Most children who have had an aortic stenosis surgical repair will live healthy lives. Activity levels, appetite, and growth should eventually return to normal.
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As the child grows, a valve that was ballooned may once again become narrowed. If this happens, a second balloon procedure or operation may be necessary to repair aortic stenosis.
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Your child's cardiologist may recommend that antibiotics be given to prevent bacterial endocarditis after discharge from the hospital.
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Individuals who had a mechanical valve replacement may need to take anticoagulants (blood thinners) to prevent blood clots from forming on the artificial valve surfaces. Regular monitoring of the blood's clotting status is very important in maintaining the most appropriate dose of anticoagulants.
Initial valve replacement is often performed using a tissue valve to avoid the need for anticoagulation, especially for females of childbearing age. Anticoagulation during pregnancy is very difficult to manage, and requires special treatment.
Repeat valve replacement is not uncommon during the lifespan. In addition, blood pressure should be closely monitored and managed.
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Consult your child's physician regarding the specific outlook for your child.
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Complementing the Cardiovascular Program of Children's Hospital of Boston is the nation's most intensive clinical and basic research program focused on pediatric heart disease. Children's Hospital is a world leader in opening new avenues of "translational research," bringing laboratory advances to the bedside and doctor's office as quickly as possible. All senior medical staff members of the Cardiovascular Program participate in clinical research activities.
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Children's Hospital of Boston has pioneered interventional catheterization repair of many types of congenital heart defects, including aortic stenosis. In many cases, this eliminates the need for open-heart surgery, allowing less pain, reduced chance of infection, and shorter recovery time. Research also continues on the design and creation of heart valves using a patient's own tissue.
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Contact Children's Hospital Boston Cardiovascular Program physicians for a second opinion.
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