Aortic Stenosis is a narrowing or obstruction of the aortic valve, causing it to not open properly and to obstruct the flow of blood from the left ventricle to the aorta.  The Aortic Valve is thickened and narrowed leading to the development of abnormally high pressure in the left ventricle.  The left ventriclular wall becomes thickened ("Hypertrophied").  Stenosis (narrowing) of the aortic valve restricts flow into the Aorta.  This leads to the presence of a heart "murmur".  Often the narrowing is mild and does not put significant strain on the heart.

 

Aortic Stenosis

Aortic Stenosis is caused by many disorders.  One cause is rheumatic fever. Other causes include calcification of the valve and congenital abnormalities.  There may be a history of other valve diseases, coronary artery disease, or a heart murmur.  While a normal valve has three parts (leaflets or cusps), a stenotic valve may have only one (unicuspid) or two (bicuspid) thickened and stiff cusps.

Balloon Valvuloplasty - Depending on the severity of the valve stenosis a procedure called balloon valvuloplasty may be used to stretch the aortic valve. During cardiac catheterization, a special catheter containing a balloon is placed across the constricted or narrowed valve. The balloon is inflated and the valve is stretched open. Treatment does not completely cure the problem and the valve sometimes tends to develop further problems with time, sometimes needing re-operation or further balloon stretching.

Sometimes the stenosis is severe and symptoms occur in infancy. Children with aortic stenosis usually have no symptoms but in some, chest pain, unusual tiring, dizziness or fainting may occur. The need for surgery is determined by the degree of severity of the stenosis. In children, the surgeon may be able to enlarge the valve opening. Although the surgery may improve the stenosis, the valve remains deformed. Eventually, replacing the valve may be necessary.

Aortic Valve Replacement

When the aortic valve is very abnormal and if it cannot be effectively repaired a valve replacement operation may be recommended. This may involve the use of an artificial valve, but in many cases the patient's own normal pulmonary valve can be used. This is called the 'Ross Operation' (or Pulmonary Autograft)

Ross Operation

The healthy Pulmonary Valve is removed and sewn into the position of the damaged Aortic Valve. The Pulmonary Valve itself is then replaced with a 'Homograft Valve'. The advantage of this operation is that the new aortic valve will grow with the child and the Homograft Valve, which can be large enough to allow for growth, is not subjected to high pressure and can last much longer in the position of the low pressure Pulmonary Valve - though it is likely that it will eventually need to be replaced at a later date.

Subaortic Stenosis

In this condition the narrowing is below the aortic valve (indicated by arrow). The effect on heart function is similar to aortic valve stenosis. In many cases the obstruction is produced by a 'membrane', but other types of subaortic stenosis also occur - notably a 'muscular' type (also called "Hypertrophic Obstructive Cardiomyopathy" (HOCM) or "Idiopathic Hypertrophic Subaortic Stenosis" (IHSS).

Lifelong medical follow-up is necessary in children with aortic stenosis because even mild stenosis can progress or worsen with age and surgical relief of the obstruction is sometimes incomplete. Following surgery the valve function often remains mildly abnormal. Some patients may have to restrict their participation in certain types of exercise, so check with your pediatric cardiologist about these kinds of exercise limitations.