Aortic Stenosis (Aortic Valve Stenosis)
Aortic valve stenosis (aortic stenosis) is a condition that interferes with blood flow between the left ventricle and aorta. The most common type of congenital aortic stenosis is aortic valve stenosis. Aortic stenosis murmur is easily heard in children. Mostly, bicuspid aortic valve is present and responds well to treatment with a heart balloon (balloon valvuloplasty).
What is Aortic Stenosis?
The most common type of congenital aortic stenosis is stenosis of the aortic valve itself, called aortic valve stenosis. The normal aortic valve contains 3 thin and flexible leaflets. When the left ventricle pumps blood into the aorta, these leaflets of the aortic valve normally separate easily and do not interfere with blood flow from the heart.
Aortic valve stenosis occurs when the
abnormal aortic valve creates a stenosis and creates an obstruction in blood flow between the left ventricle and the aorta.
How Does Stenosis Affect the Heart ?
To cope with this additional workload, more force is required to eject the left ventricular muscle (myocardium) and thus thicken the wall of the left ventricle. Increased left ventricular muscle mass, also known as hypertrophy, is rarely a problem itself. However, hypertrophy is an important sign that the patient has severe valve stenosis.
When the aortic valve is severely narrowed, the left ventricular muscle may be insufficient to meet this additional load. In these very serious but rare cases, the left ventricle may not be able to pump blood effectively. It causes heart failure in the patient. This condition is almost always seen in newborn babies born with very severe valve stenosis. Heart failure rarely occurs in childhood.
What are the Symptoms of Aortic Stenosis?
Children with aortic stenosis are usually healthy and show no symptoms. A murmur is the most common finding detected by doctors, indicating that there may be a valve problem.
In mild-to-moderate aortic stenosis, the murmur of aortic stenosis is easily heard in children and there are no symptoms in stenosis of this size.
Symptoms occur only in cases of severe aortic stenosis. A newborn born with critical aortic stenosis develops heart failure in the first days of his life. This is a condition that requires immediate treatment, such as balloon dilation or surgery.
In older children, severe aortic stenosis rarely causes heart failure. The child may have chest pain, dizziness, or fainting spells, especially associated with exercise. Severe aortic stenosis is a rare but well-documented cause of sudden death during strenuous sports activities.
How Is Aortic Stenosis Diagnosed ?
Murmur of Aortic Stenosis
Aortic stenosis is first suspected by the doctor when a heart murmur or click is heard. The murmur heard in aortic stenosis is a loud sound that blood makes as it passes through the narrowed valve. A clicking sound is heard, usually associated with the murmur that occurs when the thickened lid becomes open. These sounds can be detected by a careful heart examination by a doctor with a good heart disease training.
Other tests can confirm the presence of aortic stenosis and determine its severity. Usually an electrocardiogram (ECG) is taken. The ECG is often normal in mild to moderate aortic stenosis. In severe aortic stenosis, the ECG may show left ventricular enlargement and may prove left ventricular loading.
The most important non-invasive (non-invasive) test used to detect and evaluate aortic stenosis is echocardiography. It definitively documents that the stenosis is at the valve level. The degree of stenosis is also determined.
Echocardiography also plays an important role in excluding other problems such as left heart failure, aortic coarctation, ventricular septal defect and mitral valve stenosis that may be associated with aortic stenosis.
Exercise Stress Test
If your child has aortic stenosis, your doctor may order an exercise stress test. The exercise stress test provides information on the effect of aortic stenosis on cardiac function in children under real-life conditions (as opposed to at rest).
Patients with significant aortic stenosis may experience abnormal blood pressure responses and ECG changes during exercise. These findings help your doctor decide whether treatment is necessary; Conversely, the absence of change ensures that your doctor is confident that treatment is not yet necessary.
Cardiac catheterization is an interventional technique that allows physicians to pinpoint the extent of existing aortic stenosis. During cardiac catheterization, pressure measurements are made above and below the valve to determine the amount of stenosis. Moving images are taken to visualize the degree of stenosis.
In many cases, echocardiography has replaced cardiac catheterization for the detection and measurement of aortic stenosis.
However, from time to time, there may be a need for cardiac catheterization to support the information obtained by ECO with more interventional data. Cardiac catheterization is mostly performed together with the balloon dilatation method mentioned below.
How Is Aortic Stenosis Treated?
Children with mild aortic stenosis rarely need treatment.
However, it is worth noting that aortic stenosis can progress and children with mild aortic stenosis may eventually need treatment later in life.
It is also important to know that all treatments for aortic stenosis are palliative (does not restore the valve to normal). Therefore, it is important that all children with aortic stenosis are carefully followed up by a good pediatric cardiologist before and after successful treatment.
Catheter Angiography / Balloon Valvuloplasty
The type of treatment needed depends on the type of valve abnormality present. Often, the aortic valve is of normal size, but with varying degrees of fusion along the bicuspid (aortic valve with 2 leaves instead of 3) and the commissures (lines of opening of the leaflets). This typical form of aortic stenosis responds well to balloon valvuloplasty (dilation of the valve). Balloon valvuloplasty is performed during cardiac catheterization and does not require open heart surgery.
In newborns, it can be done by entering through the umbilical artery, thus protecting the small femoral arteries of the babies. More commonly, this procedure is performed through the femoral artery in older children. Patients are kept under observation in the hospital for at least one night.
Aortic Valve Surgery
Surgical valvotomy is an open heart surgical procedure in which surgeons open the valve along the lines of the commissural junction. In most centers, this open-heart surgery procedure has been replaced by the less invasive balloon valvuloplasty procedure.
Open heart surgery is needed for more complex valves where balloon valvuloplasty is not sufficient. These caps are due to serious calcium deposits accumulating in the leaflets. It may also narrow as a result of the lid ring being small and underdeveloped. For these cases, surgical aortic valve replacement is necessary.
The Ross Procedure is an aortic valve replacement option that can be particularly advantageous for younger children. In the Ross Procedure, the patient's own pulmonary valve is transplanted into the aortic valve position and the pulmonary valve is replaced with a homograft (human donor valve) from the right ventricle to the pulmonary artery.
Early and mid-term results of the Ross Procedure in children are quite good. It is a good option, especially for young children, as the replaced aortic valve grows with the child. It also does not require coumadin (blood thinner) treatment.
Placing a mechanical prosthesis instead of the aortic valve is a more traditional method of aortic valve replacement. Mechanical valve replacements require anticoagulant therapy. In cases where the aortic valve is small (also known as the hypoplastic valve ring), more radical surgical techniques (such as the Konno Procedure) are needed. The Konno Procedure is a technique in which the aortic valve ring is enlarged through an incision in the wall between the two ventricles. The enlarged valve ring can thus accept a more normal-sized prosthetic aortic valve or pulmonary valve autotransplant.
A child with aortic stenosis and hypoplastic valve ring may need the Ross-Konno procedure, a combination of Ross and Konno procedures.
How Are The Treatment Results?
Balloon valvuloplasty results are excellent. This technique was developed in the mid-1980s. In the vast majority of patients, this technique reduces the degree of aortic valve stenosis from severe to mild.
Children who do not have sufficient relief from the stenosis with the balloon procedure have more complex diseases such as calcified valve leaflets or small valve rings.
Balloon valvuloplasty causes valve regurgitation, but is mild in most patients. In approximately 3-5% of patients, the balloon procedure creates severe aortic regurgitation. In severe aortic regurgitation, surgical intervention may be required.
Long-term follow-up of balloon valvuloplasty shows that the reduction in stenosis continues for several years.
However, as with past surgical valvulotomy, stenosis recurs in most children within the next 5-10 years. Recurrence of the stenosis is likely due to patient enlargement and chronic valve changes. Many of these children need re-balloon valvuloplasty or surgical valve replacement.
The results of open heart surgery performed in severe aortic stenosis are also very good. When surgical valve replacement is performed, the risk of death for both prosthetic valve and Ross methods is less than 3%. The complication rate in these procedures is low. It effectively alleviates aortic stenosis and regurgitation.
The long-term concern when performing valve replacement in young children is that the size of the valve becomes smaller over time and the need for surgical valve replacement in the following years.
When adult-sized artificial aortic valves are placed in older children and adolescents, the expectation is that the valve will last for 20 years with good function.
The Ross procedure has some unique issues that need to be evaluated as children grow. The patient's natural pulmonary valve is placed in the aortic valve position and may expand over time. This enlargement can lead to varying degrees of valve regurgitation.
In addition, a conduit (conduit) is placed between the right ventricle and the pulmonary artery (to replace the natural pulmonary valve). If the Ross procedure is to be performed on an infant or young child, this right-sided conduit will need to be replaced later in childhood as the child grows.
It is important to understand that all treatments for aortic stenosis are palliative, not fully curative.
Although a good balloon dilation procedure does not create a normal valve, it allows the patient to live with only a mild aortic stenosis.
A well-performed valve replacement surgery essentially relieves all obstructions to blood flow; but it causes his child to continue his life with an artificial valve.
Regular and long-term follow-up by a pediatric cardiologist is mandatory for best results in aortic stenosis.
How Should Adults and Adolescents Be Monitored ?
Periodic monitoring should be performed in an adult with aortic stenosis; because a narrowed lid tends to narrow more over time. Some patients eventually need valve replacement. Young adults can be treated with the balloon method to open the valve. Although symptoms typically occur during strenuous exertion, activities may be limited when the stenosis becomes severe. On the other hand, patients with aortic stenosis can do their activities normally. These patients are also at risk of infective endocarditis and should pay close attention to their oral hygiene and dental care.
Many adult patients also have leaks from the aortic valve, also called aortic regurgitation, in other words, aortic regurgitation. In other words, varying degrees of stenosis and leakage can coexist. Guidelines have been developed to help us decide what is the best course of treatment for each patient.