| FACTS
ABOUT AORTIC STENOSIS
What is the aortic valve?
The aortic valve is located between the main pumping chamber
of the heart, the left ventricle, and the aorta, the blood vessel
that carries blood full of oxygen to the rest of the body. The aortic
valve normally has three thin leaflets that open widely as the left
ventricle pumps the blood out of the heart. When the left ventricle
has finished ejecting the blood, the backflow of blood against the
valve leaflets closes the aortic valve, preventing blood from leaking
back into the left ventricle.
What is aortic stenosis?
Aortic stenosis refers to a narrowing of the aortic valve opening.
This is often due to an age-related thickening and calcification
of the valve leaflets. There are also inflammatory conditions involving
the aortic valve that lead to thickening of the leaflets and fusion
along the margins of the valve cusps. Rheumatic heart disease may
cause these changes. Some aortic valves are imperfectly formed at
birth, having two rather than the usual three leaflets. These two
leaflet or bicuspid valves tend to wear out sooner than normal by
becoming thickened, fused and  non-pliable.
The end result of aortic stenosis is a progressive narrowing of
the valve to the point where blood flow across the valve becomes
limited. When this happens, patients have a decline in the ability
to exert, increased shortness of breath, heart failure, chest pain
and fainting episodes. Once the aortic valve becomes narrowed to
the point where symptoms are present, there is a significant increase
in the chances of dying suddenly.
What causes aortic stenosis?
Aortic stenosis is caused by many disorders. One cause is rheumatic
fever that is becoming very uncommon in industrialized nations,
but is still prevalent in third-world countries. Other causes include
calcification of the valve and congenital abnormalities (problems
present at birth). There may be a history of other valve diseases,
coronary artery disease, or heart murmur.
Aortic stenosis occurs in approximately
5 out of 10,000 people. It is more common among men. Symptoms often
do not appear until middle age or older.
How is aortic valve disease diagnosed?
Both narrowed and leaking aortic valves cause the blood flow across
the valve to become turbulent. This turbulence creates a sound that
can be heard with a stethoscope. This is called a heart murmur.
The diagnosis of aortic valvular disease starts with a physical
examination in which a heart murmur is heard. Heart murmurs due
to the aortic valve have a characteristic sound and location. Not
all murmurs are due to aortic stenosis.
An echocardiogram, an ultrasound examination
of the heart, is a useful way to look at the aortic valve to see
if there is significant disease present. The appearance of the leaflets
can provide important information as to thickening, mobility and
whether there are two or three leaflets. The amount of leakage and
narrowing can be determined by Doppler ultrasound. The effect of
the aortic valve disease on the heart function can also be assessed.
If the echocardiogram suggests that the aortic
valve is significantly diseased to warrant surgical replacement,
a cardiac catheterization is performed. This is a hospital test
that involves measuring pressures in various heart chambers using
small tubes or catheters inserted into an artery and a vein of the
groin or arm and directed into the heart. Motion picture X-rays
are also obtained to assess the heart function and the appearance
of the valve and the aorta. X-ray pictures are usually obtained
of the coronary arteries at the same time. If there is coexisting
coronary artery disease, those arteries are usually bypassed at
the time of the aortic valve surgery.
What are the symptoms of aortic stenosis?
Aortic stenosis might show no symptoms until late in the disease
process. Symptoms can include:
- fainting or weakness with activity
- breathlessness with activity
- chest pain, angina-type
- blackout spells
How is aortic stenosis diagnosed?
Examination shows vibration or movement felt by holding the hand
over the heart. There is almost always a heart murmur, click, or
other abnormal sounds when examining the chest with a stethoscope.
There may be faint pulses or changes in the quality of the pulse
of the arteries of the neck. Blood pressure may be low.
Certain diagnostic imaging tests can reveal
aortic stenosis. They include:
- an echocardiogram
- a chest X-ray
- a cardiac catheterization
An ECG may show left ventricle thickening
or enlargement and arrhythmias (unusual pattern of heart beats)
such as ventricular tachycardia or sinus bradycardia.
This disease may also alter the results of
the following:
- a chest MRI
- an aortic angiogram
How is aortic stenosis treated?
Mild to moderate aortic valvular disease requires no specific treatment.
Your physician will want to see you periodically to be certain the
disease is not progressing. Your physician will also obtain periodic
echocardiograms to follow the status of your aortic valve.
Because diseased heart valve are more susceptible
to infection when bacteria are present in the blood stream, antibiotics
should be given before any procedures that are likely to cause bacteria
in your blood stream. This would include dental work (including
dental cleaning), genitourinary procedures, colonoscopy, sigmoidoscopy
and the like. If you have aortic valvular disease, please ask your
doctor about antibiotic prophylaxis (antibiotic drugs given in advance
to help make sure that you don't get an infection during a procedure).
Medications may include diuretics, digoxin,
and other medications to control heart failure. Symptomatic people
may be advised to avoid strenuous physical activity. People who
have symptoms (difficulty breathing, chest pain, syncope) and documented
aortic stenosis should consider early surgery if the valve is tight
enough. There is a 50% mortality in the next 2-5 years if the valvular
problem is not corrected.
Surgery involves replacement of the aortic
valve. There are a variety of heart valves available. There are
man made mechanical valves that have great durability but which
require life long blood thinners (coumadin) to prevent clots from
forming. There are valves constructed from animal tissue. These
include pig aortic valves and valves made from pericardium. Aortic
valves from human cadavers may also be used. In general the tissue
valves require only short term blood thinners but they have a limited
life of around ten years. If aortic valve replacement is recommended,
your cardiac surgeon and cardiologist will discuss the various options
with you.
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