The aortic valve is the valve between the left ventricle and the aorta. Aortic stenosis occurs when the aortic valve is narrowed or thickened and causes obstruction. This makes it hard for the heart to pump blood to the body, and the left ventricle needs to squeeze to a higher pressure to overcome the obstruction.
A normal aortic valve has three leaflets or cusps, but a stenotic valve may have only one cusp (unicuspid) or two cusps (bicuspid). Sometimes a bicuspid aortic valve has three leaflets, but two of them are stuck together or fused so that only two leaflets open. Bicuspid aortic valves may not cause any significant obstruction early in life, but may become stenotic (thickened) or regurgitant (leaky) in adulthood.
Sometimes stenosis is severe and symptoms occur in infancy. If it is very severe or “critical” aortic stenosis, not enough blood can get to the body to meet the demands of the body. If the aortic valve does not open at all and is incompletely formed, it is called aortic atresia.
Aortic stenosis is diagnosed after a physician takes a history and performs a physical examination. With mild or moderate narrowing, there may be no symptoms. An abnormal heart murmur is usually noted on physical examination along with other features, which suggest the diagnosis of aortic stenosis. With severe or critical aortic stenosis, the abnormal murmur may not be present, though there are findings of shock which suggest the possibility of a heart defect.
The diagnosis and severity of the aortic stenosis is confirmed with an echocardiogram. Depending on the severity, no interventions may be required.
Children with mild or even moderate aortic stenosis usually do not have symptoms. If symptoms occur, they may include:
With severe narrowing, there may be symptoms at birth which consist of:
The need for intervention depends on how bad the stenosis is, and other considerations such as the size of the patient, the possibility of needing an artificial valve and the specific nature of the valve abnormality.
In very severe or critical aortic stenosis, intervention is required soon after birth to try to achieve normal blood flow to the body. Initially, a drug called prostaglandin may be given to open up the ductus arteriosus to allow blood flow from the pulmonary artery to the aorta. This can occur in babies because the pressure and resistance in the pulmonary artery is high in newborn infants (later in life, the blood may flow from the aorta to the pulmonary artery instead of going to the body). The prostaglandin treatment is only temporary since procedures are needed to relieve the obstruction and allow enough blood to get to the body.
If the left ventricle is an adequate size, the obstruction across the aortic valve may be relieved by an interventional cardiac catheterization procedure. The procedure involves placing a balloon across the valve and blowing it up. This dilates the valve narrowing and is called balloon valvuloplasty. If the interventional catheterization is not possible or successful, open-heart surgery is needed to relieve the obstruction.
Almost all surgical operations and cardiac catheterizations have the risk of bleeding, infection and sedation. Open-heart surgery has special risks of cardiopulmonary bypass. Special risks of valvuloplasty in the catheterization laboratory include rupture of one of the blood vessels as the balloon is inflated.
With either procedure, the aortic valve remains deformed, and another intervention to relieve the stenosis or even valve replacement may be required in the future. Additionally, both procedures usually end up with at least some amount of aortic valve regurgitation. Depending on the amount, this may need long-term treatment. This treatment includes valve replacement with a human or pig valve (known as a homograft or xenograft), replacement with a prosthetic (artificial) valve or a surgery known as the Ross procedure.
Children with aortic stenosis need lifelong medical follow up. Even mild stenosis may worsen over time, and surgical relief of a blockage is sometimes incomplete. Check with your pediatric cardiologist about limiting certain types of exercise.