Aortic stenosis is a form of congenital heart disease in which the valve in the heart that allows blood to flow to the body is narrowed. Read on for information about the characteristics of the defect at birth and the treatment and follow-up care that is necessary into adulthood.
Aortic Valve Stenosis in Childhood
In aortic valve stenosis, the valve between the lower left chamber of the heart (left ventricle) and the main artery carrying blood from the heart to the body is narrowed. Aortic stenosis can be due to:
- Fusion of the valve’s leaflets, the door-like structures that open to allow blood to flow out of the heart and close to prevent it from leaking backward, or
- A “doorway” for blood flow that is too small.
Aortic stenosis is rare in infancy. Its incidence increases with age and it becomes a common congenital heart disease in the third decade of life, particularly for those who are born with a bicuspid valve. The normal aortic valve has three leaflets. Some people are born with two of these leaflets that are partially or completely fused together, resulting in two functional leaflets rather than the usual three. Valvular aortic stenosis has an extremely wide range of presentation. It can be so severe that emergency intervention is necessary after birth. For others, the amount of narrowing can be relatively stable for quite some time. Others may have an abnormal-appearing valve, but it may function normally for a long time.
If aortic stenosis is mild or moderate, there may be no symptoms. If it is severe, symptoms may include:
- Shortness of breath
- Fainting (syncope)
- Abnormal heart rhythm
- Congestive heart failure
- Sudden cardiac death due to severe ventricular thickening and diminished coronary blood flow
Progression and Possible Complications
Aortic stenosis may be mild, moderate, severe, or critical. Mild narrowing of the aortic valve opening usually causes no problems. However, with moderate or severe narrowing, the heart’s left ventricle must work harder to pump blood through a too-small opening. The extra work leads to thickening of the wall of the ventricle, a condition called left ventricular hypertrophy.
Eventually the overworked left ventricle can fatigue, causing it to fail in its efforts to pump blood to the body, a condition called heart failure. Left ventricular heart failure can lead to high blood pressure in the lungs due to an inability for oxygenated blood to fill the overworked left ventricle easily. Shortness of breath and, eventually, right heart failure may occur. Left ventricular failure will also result in the heart’s inability to provide the body with the amount of blood it needs, leading to symptoms of tiredness or fatigue.
Critical aortic stenosis is the extreme narrowing of the aortic valve in newborns. Before birth, a baby can survive well with only one well functioning ventricle. That is not the case after birth. With critical aortic stenosis, the left ventricle is not able to pump blood adequately through the narrowed aortic valve and into the body. As a result, a child born with this defect will become very ill soon after birth and may not survive without immediate treatment. This usually involves starting a prostaglandin E1 infusion to keep a blood vessel that normally closes after birth called the ductus arteriosus open to allow blood to get to the body. An interventional catheterization procedure called a balloon aortic valvuloplasty may need to be performed shortly after birth. In this procedure a specifically sized balloon is inflated within the valve to stretch the valve open.
Because the aortic valve is abnormally formed, progressive leakage of the valve may occur over time. Balloon valvuloplasty of the aortic valve can make this leakage worse. Usually, the amount of leakage of the valve will determine whether one may undergo another balloon valvuloplasty in the future if the aortic valve were to renarrow.
Oftentimes, the ascending aorta (area above the aortic valve) may become progressively more dilated over time. While some of this enlargement may be a result of the stress of blood being directed with high velocity toward the wall of the aorta, it is becoming clearer that some people with aortic valve problems also have an intrinsic abnormality in how the wall of the aorta is formed. As a result, the weaker aortic wall may become enlarged and develop what is called an aneurysm. As the aortic wall becomes progressively more enlarged, there is an increased risk of tearing of the aortic wall, called a dissection, or even aortic rupture. This can be a sudden life-threatening event.
No treatment is generally recommended for mild aortic stenosis. However, ongoing monitoring of the condition is important to determine any change toward a moderate or severe level.
If aortic stenosis is moderate or severe, an interventional cardiologist may be able to use a special balloon catheter to separate the fused valve leaflets – and thereby widen the opening for blood flow.
Balloon dilation (widening) of the aortic valve, using a catheter (a thin, flexible tube) with an inflatable balloon at its tip, may be recommended in some cases to open the valve wider. This procedure is performed in the hospital's cardiac catheterization laboratory by specialized cardiologists.
Follow-up Care into Adulthood
Adults who have mild aortic valve stenosis that does not require treatment should have follow-up with their cardiologist to monitor for progression of valve narrowing or heart failure. Tests that can be done include an echocardiogram, electrocardiogram, exercise stress test, computed tomography (CT) scan, or magnetic resonance imaging (MRI) scan. Your cardiologist may restrict some of your activity depending on the severity of the aortic stenosis. The narrowing may progress to the point where a patient will require treatment either by a balloon catheter or surgery. Some valves will need to be replaced by a prosthetic valve.
Some patients have fusion of the aortic valve leaflets, which causes valve narrowing. In this situation, the normal three leaflets work like two. This is called “bicuspid aortic valve.” Not only is the valve abnormal, but the vessel that carries blood from the heart to the rest of the body (aorta) can enlarge or dilate near the aortic valve. In some circumstances, the aorta will dilate so large there that is a risk of the vessel tearing. This can be treated by surgery in which the dilated portion of the aorta is replaced by a prosthetic tube.
Consult your cardiologist about the kind and level of activity that is appropriate for you, given your condition. And check with him or her before trying new activities. Generally more restriction will be placed for those with higher amounts of valve narrowing or leakage.