What is Aortic (Valve) Stenosis?
Aortic stenosis is a condition that blocks blood flow between the left ventricle of the heart and the aorta. There are many causes. These causes include muscular obstruction below the aortic valve, a block at the valve itself, or aortic narrowing right above the valve.
The most common form of aortic stenosis is a block at the valve itself. This is called aortic valvar stenosis.
View 2D images of Aortic Valvar Stenosis.
The normal aortic valve consists of three thin and flexible leaflets. When the left ventricle pushes blood into the aorta, normal aortic valves spread apart easily. There is no blockage of the blood going out of the heart.
Aortic stenosis happens when defects of the aortic valve lead to narrowing between the left ventricle and the aorta.
The most common defect happens when the aortic valve has only two (instead of three) leaflets. This is called a bicuspid aortic valve (or BAV). Often the valve leaflets are thicker and less flexible than normal. The lines of separation between them (called commissures) are stuck together. When the aortic valve does not open as easily, the left ventricle must work harder to push blood into the aorta.
To make up for this additional work, the muscle of the left ventricle (the myocardium) slowly gets thicker to give a more powerful push to the blood. The bigger left ventricular muscle (called hypertrophy) is not a problem on its own, but hypertrophy is a sign of valve blocking.
When the aortic valve is really blocked, the left ventricular muscle may not be able to do its job. In these very severe but rare times, the left ventricle may not pump blood well. The patient may develop heart failure. This mostly happens in infants with severe valve blockage. Heart failure rarely happens later in childhood.
What are the Signs and Symptoms of Aortic Stenosis?
Children with aortic valvar stenosis are generally healthy. They don’t have symptoms. A heart murmur is the most common sign seen by a doctor that shows there may be a valve problem.
Children with mild-to-moderate degrees of aortic valve stenosis have easily detectable heart murmurs. They won’t have any symptoms at all.
Symptoms happen with severe aortic stenosis. A newborn with critical aortic valve stenosis develops heart failure in the first days of life. This is an emergency that requires immediate treatment.
In an older child, severe aortic stenosis rarely causes heart failure. The child may have chest pain, lightheadedness or fainting spells with exercise. Severe aortic stenosis is a rare cause of sudden death during sports activities.
How is Aortic Stenosis Diagnosed?
Aortic stenosis is suspected because a doctor hears a heart murmur or click. There is often a clicking sound when the thickened valve snaps to its open position. These sounds can be found through careful examination of the heart by a doctor.
Other testing may show aortic stenosis. Tests may help document how severe it is. An electrocardiogram is often done. The electrocardiogram results are normal with mild-to-moderate aortic stenosis. With severe aortic stenosis, the electrocardiogram can show enlargement of the left ventricle. It may show left ventricular strain.
The echocardiogram (or "echo") is the most important test to find and evaluate aortic valve stenosis. The echocardiogram shows that the blockage is at the valve level. It can estimate how much valve obstruction there is.
The echocardiogram is also important in looking for other problems that may be associated with aortic stenosis. This may include left ventricular failure, coarctation of the aorta, ventricular septal defect or mitral valve stenosis.
Your doctor may order an exercise stress test if your child has aortic stenosis. The exercise stress test gives information about how the aortic stenosis affects how well the heart works.
During exercise, patients with aortic stenosis may show abnormal blood pressure or electrocardiogram changes. These findings may help your doctor determine if therapy is needed. If there are no changes during the test, this may help your doctor know that treatment is not yet needed.
Cardiac catheterization is an invasive technique that allows doctors to measure how much aortic stenosis is present. During cardiac catheterization, pressure measurements are made above and below the valve. This measures the amount of blockage. Pictures are taken to see the degree of valve obstruction. Echocardiography has replaced cardiac catheterization in many cases to find and measure aortic stenosis. But sometimes it may be necessary to do a cardiac catheterization to add to the information from the echo studies. Cardiac catheterization can be combined with a balloon dilation procedure.
How is Aortic Stenosis Treated?
Children with mild aortic stenosis rarely need treatment.
Aortic stenosis may continue to get worse. Children with mild disease may need treatment later in life if their aortic stenosis worsens.
All treatment for aortic valve stenosis is done to help improve symptoms—it does not return the valve to a normal condition. Before and after treatment, it is important that all children with aortic stenosis follow up with a cardiologist for the rest of their life.
The type of treatment needed depends on the type of valve defect. Defects like a bicuspid aortic valve usually respond well to balloon dilation procedures. Balloon dilation valvuloplasty is done at the time of cardiac catheterization. It does not require open-heart surgery. In the newborn, it can be done through the umbilical artery. In older children, the procedure is done through a femoral artery. Patients are usually kept in the hospital overnight, but the procedure can be done as an outpatient procedure in some children.
Surgical valvotomy is an open-heart procedure where the surgeon opens the valve. But in many cases, this procedure has been replaced by the less invasive balloon dilation valvuloplasty technique. Open-heart surgical procedures are needed for more complex valves. These valves may be blocked by severe calcium deposits in their leaflets. The valve ring may be small and underdeveloped. For these conditions, surgical aortic valve replacement will be needed.
The Ross procedure is an aortic valve replacement option that may be best for young children. In the Ross procedure, the patient's own pulmonary valve is transplanted to the aortic valve position. The pulmonary valve is replaced with a homograft (human donor valve) from the right ventricle to pulmonary artery. It is a good option for young children because the replaced aortic valve can grow with the child. It also does not need the use of a blood thinner.
A more traditional aortic valve replacement procedure involves putting a mechanical prosthesis in the aortic valve position. Anticoagulation therapy (blood thinner) is needed with any mechanical valve substitute. When the aortic valve is small (also known as a hypoplastic valve annulus or ring), more complex surgical techniques (like the Konno procedure) are needed. The Konno procedure makes the aortic valve ring larger with a cut into the wall between the two ventricles. The larger valve annulus can then accept a more normal-size prosthetic aortic valve or pulmonary valve auto transplant.
A child with valvar aortic stenosis and a hypoplastic valve ring might need a Ross-Konno procedure. This is a combination of the Ross procedure plus a Konno procedure.
Results of Treatment
The results of balloon dilation valvuloplasty have been excellent. Most large medical centers have experience with it. The technique decreases the aortic valve blockage from severe to mild in a large number of patients.
If the blockage does not significantly improve with a balloon dilation procedure, that usually means the patient has a more complex disease.
Balloon dilation valvuloplasty does cause valve insufficiency (or leakage). This is mild in most patients. In about 3% to 5% of the patients, the balloon procedure will create severe aortic valve insufficiency. Severe aortic valve insufficiency may need surgery.
Long-term follow-up studies of balloon dilation valvuloplasty show that relief of blockage lasts for several years.
But valve obstruction does happen again in many children over the next five to 10 years. This is because of patient growth and chronic valve changes. Many of these children will need repeat balloon dilation or surgical valve replacement procedures.
The outcomes of open-heart surgical procedures for severe aortic valvar stenosis have been excellent. The mortality risk for surgical valve replacement, either prosthetic valve or the Ross procedure, is less than 3% in experienced medical centers. These procedures correct all aortic stenosis and insufficiency with low complication rates.
When valve replacements are done in young children, the long-term concern is that the child will outgrow the size of the artificial valve. They may need a repeat surgical valve replacement in later years. When adult-sized artificial aortic valves are implanted in large children and teens, they are expected to last 20 years or more with excellent function.
The Ross procedure has several unique issues that need evaluation as children grow. The patient's native pulmonary valve is implanted in the aortic valve position. It may dilate (get wider). This dilation may lead to some valve leakage over time.
A conduit is put between the right ventricle and pulmonary artery (to replace the native pulmonary valve). If the Ross procedure is done in an infant or small child, this right-sided conduit will need to be replaced as the child grows.
It is important to understand that all treatments for aortic stenosis are done to help improve symptoms, not cure the defect. A balloon dilation procedure may leave the patient with only mild aortic stenosis, but not a normal valve. A valve replacement surgery will correct all outflow blockage, but leaves the child with an artificial valve.
Long-term follow up, with regular evaluations by a cardiologist, is important to give the highest quality outcome for patients with aortic stenosis.
Adult and Adolescent Management
An adult with aortic valvar stenosis needs regular follow-up throughout their life. A stenotic or narrow valve tends to become narrower over time. Some patients may need to have an aortic valve replacement. Young adults may be treated with a balloon procedure to open the valve. Activities may be limited when stenosis is becoming severe. Symptoms tend to happen during strenuous exertion. Otherwise, patients with aortic stenosis may do normal activities. These patients are at risk for infective endocarditis (a heart infection). They should maintain excellent oral hygiene and regular dental care.
Many adult patients also have some leakage of the aortic valve, called aortic regurgitation. They may have narrowing and leakage of their valve. Care and treatment are customized for each patient.
Learn more about the Adolescent and Adult Congenital Heart Disease Program.
