Aortic valve stenosis can be thought of as narrowing of the aortic valve. This valve is positioned within the aorta, which is the biggest artery emerging from the heart, and left ventricle.
What causes narrowing of the aortic valve?
Aortic Stenosis (acquired/degenerative): This is the commonest cause in adults. This problem is a natural part of the aging process in some people. Calcium begins to deposit on the leaflets of the valve. As a result, the valve gets hardened and will be unable to function properly, resulting in stenosis of the valve. Occasionally, the valve becomes as hard as a stone.
Aortic Stenosis (Congenital)
Under normal conditions, the aortic valve is made up of three leaflets. However, in this case the infant is born with a valve that is made up of only two leaflets (bicuspid aortic valve).This abnormality induces a turbulent and abnormal flow, which causes trauma to the leaflets. This in turn leads to calcification and fibrosis. The calcification progress to produce clinically-evident aortic stenosis by the time the individual is 50 years or so.
Aortic Stenosis (rheumatic)
As the name suggests, the cause for this is rheumatic fever and it represents the least common type of aortic stenosis among adults. This type of disease is very rarely an isolated disease, and generally occurs along with stenosis of the mitral valve.
Results of Aortic Stenosis
It is true that stenotic aortic valves do cause a great amount of pressure on the left ventricle. This ventricle is forced to work extra hard to push the blood through the narrow opening. As a result of this, the ventricular cardiac muscle gets thickened, or hypertrophied, until it outgrows its blood supply. Eventually the left ventricle will be unable to push enough blood past the valve. When this happens, there is a possibility that the heart may fail, and patients often develop serious symptoms. Serious left ventricular hypertrophy will cause a significant amount of abnormalities in the coronary blood flow. Such abnormalities will eventually lead to angina or chest pain.
Symptoms and signs
- Asymptomatic for a long time
- Blackouts or syncope
- Angina or chest pain: This happens in approximately two-thirds of patients who suffer from a severe form aortic stenosis. About one half of these patients will have an underlying CAD (coronary artery disease). Angina in those patientswho do not suffer from coronary artery disease is generally due to an increased need of the thickened ventricle for blood.
- Exercise intolerance and easy fatiguability
- Shortness of breath
- Heart failure
- Infectiveendocarditis can occur in younger patients who suffer from aortic stenosis. This is most unlikely in the elderly who suffer from severely calcifiedvalves.
- Irregular heartbeats
- Rarely a stenotic valve can be the sourceof a calcium emboli. This can occur in the brain and cause a stroke.
- On examination, the physician will be able to hear a heart murmur over the chest.
1. Electrocardiogram: aids in detecting abnormal patterns of the left ventricle that has been thickened.
2. Chest X-Ray: Turns up normal in most of the patients suffering from aortic stenosis. It can show the increase in thickness of the left ventricle.
- This is the most common noninvasive diagnosticmethod used in the assessment of the significance of the stenosis.
- Identifies the severity and the causes of the stenosis.
- Evaluates the cardiac chamber function and size.
4. Cardiac Catheterization
Coronary angiography is warranted in those patients who need to undergo aortic valve replacement and in whom coronary artery disease is suspected.
Grading The Degree Of The Stenosis
The normal area of an adult aortic valve averages3.0 to 4.0 cm^2.
Currently accepted criteria for grading are:
- Mild stenosis of the aorta: area >1.5 cm^2
- Moderate stenosis of the aorta: area 1 to 1.5 cm^2
- Severe stenosis of the aorta: area <1.0cm^2
Treatment is largely based on thepresence or absence of symptoms, rather than on size (aortic valve area).
- Prophylactic treatment, using antibiotics, against infective enodocarditis before any dental or surgical procedure.
- Diuretics in the case of developing heart failure.
- Percutaneous aortic balloon valvuloplasty: in which the valve is widened via cardiac catheterization. This is generally helpful in patients who cannot be operated on.
Surgical Treatment in the form of heart valve replacement surgery