What is aortic stenosis? Aortic stenosis is a blockage of blood flow between the left ventricle and the aorta due to aortic valve disease, in some cases. This includes: subaortic myocardial obstruction, valvular self-infarction, or supra-aortic stenosis. The most common of these is aortic valve self-infarction, or aortic stenosis. The normal aortic valve consists of three thin, pliable leaflets. When blood is ejected from the left ventricle into the aorta, the normal aortic valve leaflets can open sufficiently without causing obstruction of blood flow When the aortic valve is abnormal, resulting in narrowing or obstruction between the left ventricle and the aorta, aortic stenosis develops. The most common cause is that there are only two aortic valve leaflets instead of the normal three, known as the bileaflet aortic valve. Usually, these leaflets are thickened and less flexible than normal, and the dividing lines between the leaflets (leaflet junctions) are fused to varying degrees. When the aortic valve does not open freely, the left ventricle must contract more forcefully to pump blood into the aorta. As a result of compensation, the left ventricular muscle (myocardium) gradually thickens to provide additional contractile force. Therefore, thickening of the left ventricular muscle (myocardial hypertrophy) may not be a problem in itself, but often indicates the presence of aortic stenosis. When aortic stenosis is very severe, the left ventricular muscle may not be able to compensate effectively. In these rare but very severe cases, the left ventricle may not be able to pump effectively and the patient may progress to heart failure. This condition almost always occurs in neonates with severe valvular stenosis and is rarely seen in childhood. What are the signs and symptoms of aortic stenosis Children with aortic stenosis are usually asymptomatic and healthy and active. A heart murmur is usually the most common positive sign on physical examination. Mild to moderate aortic stenosis can easily be detected as a heart murmur but is usually asymptomatic. Symptoms are most often seen in children with severe aortic stenosis. Severe aortic stenosis in newborns can present with heart failure as early as the first day of life. This condition requires urgent management: balloon dilation or surgery. In older children, severe aortic stenosis rarely presents with heart failure. The child may have chest pain, dizziness, or fainting, especially during activity. Severe aortic stenosis is also one of the rare causes of sudden death during vigorous physical activity that has been identified. How is the diagnosis made? Aortic stenosis is usually first suspected when a doctor hears a heart murmur during an examination. The heart murmur in aortic stenosis is a rough sound caused by the passage of ejected blood through the stenotic valve orifice. It is often combined with a slapping sound when the thickened valve opens. A physician with good cardiac diagnostic training can detect these sounds with careful examination. Other tests can determine the presence of aortic stenosis and help detect its severity. An electrocardiogram is usually routine. In mild to moderate aortic stenosis, the ECG is usually normal. In severe aortic stenosis, the ECG can suggest an enlarged left ventricle or even left ventricular strain. . Echocardiography is the most important noninvasive means of detection and evaluation. Echocardiography accurately depicts stenosis at the valve level, and color Doppler is used to estimate the degree of valve stenosis. It is also important in that echocardiography also rules out other problems that can accompany aortic stenosis, such as possible combined left heart failure, aortic constriction, ventricular septal defect, or mitral stenosis. If your child has aortic stenosis, your child’s doctor may also perform an exercise tolerance test. The exercise tolerance test provides information about the effect of aortic stenosis on cardiac function in the non-resting state, i.e., during daily activities of the child. During exercise, patients with severe aortic stenosis may have an abnormal blood pressure response or electrocardiographic changes. These changes may help your physician clarify the need for treatment, or conversely, treatment may not be necessary for the time being. Cardiac catheterization is an invasive technique that enables physicians to accurately quantify the severity of aortic stenosis. Cardiac catheterization technology can be used to measure the severity of obstruction by measuring the pressure in the distal and proximal portions of the valve, while the motion pattern of the lower valve can be photographed to show the possible presence of valve obstruction. For more than 15 years, echocardiography has largely replaced cardiac catheterization as a tool for detecting aortic valve stenosis. Nevertheless, from time to time, it may be necessary to perform cardiac catheterization to supplement the information obtained by cardiac ultrasound. Balloon dilatation is often performed at the same time as cardiac catheterization. What are the common treatments? Mild aortic stenosis in children generally does not require treatment. However, aortic stenosis can progress gradually, and mild stenosis may eventually require treatment. It is also important: it must be clear that all treatment is symptomatic relief (i.e., it does not completely restore the valve to normal). Therefore, follow-up by a qualified cardiologist is required both before and after treatment. The treatment depends on the specific type of valve abnormality. The most common type of aortic stenosis is a normal-sized bileaflet malformation with varying degrees of leaflet junction fusion. This “classic” lesion is well suited for balloon dilation. Balloon dilation can be performed at the same time as cardiac catheterization and does not require open surgery. In neonates, it can be performed through the umbilical artery, obviating the need for the femoral route. More typically, older children undergo the procedure through the femoral artery. Patients often need to be hospitalized, but some children can be treated on an outpatient basis. Surgical valvotomy is a happy procedure in which the leaflet junction is cut at the fusion; in many centers, this happy procedure has been replaced by minimally invasive balloon dilation. For more complex valve lesions, simple balloon dilation is not indicated, and open cardiac surgery must then be used for treatment. These valve leaflets may have severe calcification, or the valve annulus itself may be small and poorly developed. In these cases aortic valve replacement surgery must be performed. One type of aortic valve replacement, called the Ross procedure, is particularly suitable for pediatric patients because of the growth potential of the replaced aortic valve, which can grow larger as the child develops and does not require anticoagulation. The procedure replaces the diseased aortic valve by moving the child’s own pulmonary valve to the aortic valve position, and the original pulmonary valve is replaced with a homologous (human donor) pulmonary artery conduit, with highly satisfactory early to mid-term results. More conventional aortic valve replacement procedures require the placement of a mechanical aortic valve. Placement of any mechanical valve requires anticoagulation therapy. When the aortic valve is small (also known as annular development), a more radical surgical approach is required, as is the case with the Konno procedure, in which the septum between the two ventricles is cut and the aortic annulus is enlarged. The enlarged annulus can then be placed into a normal-sized prosthetic aortic valve or, in the Ross-Konno procedure, into a normal-sized pulmonary valve. Treatment Results . The results of balloon dilatation have been well established. This technique was developed in the mid-1980s, and most major medical centers have accumulated some experience with it. This technique reduces severe aortic stenosis to a mild degree in most patients. Children whose lesions do not improve effectively with balloon dilation usually have more complex problems, such as valve calcification or small annulus. Balloon dilation can cause valve regurgitation, but it is usually very mild. In about three to five percent of patients, balloon dilation will result in severe aortic valve closure insufficiency requiring surgical intervention (usually rarely emergency). Long-term follow-up studies of balloon dilation have shown that balloon dilation provides excellent relief of valve stenosis that is maintained for several years. However, as with surgical valvotomy in the past, revalvular stenosis occurs in many children over the next 5-10 years, perhaps related to patient growth and chronic valvular disease. Many of these children will require reballoon dilatation or surgical heart valve replacement. Direct intracardiac surgery is highly effective in the treatment of severe aortic stenosis. In experienced centers, the mortality rate for heart valve replacement surgery, either with a prosthetic valve or Ross procedure, is less than three percent… Each of these procedures is effective in reducing aortic stenosis and insufficiency and maintains a low complication rate. For valve replacement in young children, our ongoing concern is that as the child grows up, the original prosthetic valve that was placed will become relatively small and require another valve replacement. Once an adult-sized prosthetic aortic valve is placed in larger children and adolescents, it can maintain better function for at least 20 years or longer. As children grow, the Ross procedure also faces several unique problems. The patient’s original pulmonary valve implanted in the aortic valve position may dilate and eventually develop some degree of regurgitation. In addition, the tube placed between the right ventricle and the pulmonary artery (to replace the original pulmonary valve) is also an issue to consider. If the person undergoing the Ross procedure is an infant or small child, this tube will need to be replaced when the child is a little older. It is most important to recognize that all treatment for aortic stenosis is symptomatic relief, not a cure. A successful balloon dilation procedure may leave only a mild aortic stenosis, but still not a normal valve. A successful heart valve replacement procedure will essentially eliminate all obstruction, but place an artificial valve in the child’s body. Long-term follow-up, with regular evaluation by a qualified cardiologist, is a guarantee of further improvement of the outcome.