What is aortic valve stenosis?
stenosis is a narrowing of the aortic valve. The aortic valve allows blood to
flow from the heart's lower left chamber (ventricle) into the
aorta. Stenosis prevents the valve from opening
properly, forcing the heart to work harder to pump blood through the valve.
This causes pressure to build up in the left ventricle and thickens the heart
muscle. The heart can compensate for aortic valve stenosis and the resulting
pressure overload for a long time. But eventually the heart will not be able to
maintain the extra effort needed to pump blood through the narrowed valve,
Is valve replacement surgery the only treatment for aortic valve stenosis?
If you have symptoms of aortic valve stenosis, surgery
to replace the aortic valve is the only effective treatment. Symptoms include
chest pain, fainting, lightheadedness, shortness of breath, and heart
palpitations. Your doctor may prescribe medicines to treat your symptoms, but
after the valve is damaged, it needs to be replaced.
will develop fairly quickly if you have symptoms of severe stenosis and do not
replace the valve. Most people who have symptoms of severe aortic valve
stenosis die within 2 to 5 years if they do not have valve replacement
What are the differences between mechanical and tissue valves?
You and your doctor will need to weigh the shorter
durability of a tissue valve, which increases the likelihood that you will need
another replacement valve, against the drawbacks of taking anticoagulant
medicine for the rest of your life or as long as you have a mechanical valve.
These medicines can increase the risk of bleeding.
valves last at least 20 to 30 years in most cases. The greater durability of a
mechanical valve makes it less likely that you will have to replace the valve
in your lifetime. While mechanical valves can break down, this is very
In spite of chemical treatments to improve durability,
tissue valves typically last about 8 to 15 years. They usually fail because of
the same calcification process that affected the original valve. Tissue valves
may also tear or become infected. When tissue valves are used, a second valve
replacement may be necessary.
In general, mechanical valves are
the preferred choice for children, teens, and adults age 60 and younger, all of
whom will likely outlive a tissue valve and need another valve replacement.
Tissue valves are most appropriate for people who are less likely
to outlive their valves, which includes people who:
- Are older than 65.
- Are younger
than 60 and have severe lung disease.
- Have heart
coronary artery disease.
- Have kidney
- Have a life expectancy of less than 10 years.
Because anticoagulant medicine is needed for only a
short period after surgery, a tissue valve may also be the best choice:
- When the risks of bleeding associated with
anticoagulants are too great.
- If you do not want to limit your
activities because of the risks of bleeding associated with
- If you don't want to take anticoagulants.
Why is blood clotting more likely with a mechanical valve?
Because your body recognizes a mechanical valve as
artificial, your blood has a tendency to clot on the surface of the valve. The
valve components are also hard, unlike the soft tissue of a natural valve, and
can tear blood cells as they pass through the valve, causing clots to form. To
prevent blood clots, people who receive mechanical valves must take
anticoagulants, such as warfarin (for example, Coumadin), for the rest of their
lives. This medicine can increase the risk of severe bleeding from an injury
and can cause a number of side effects.
Tissue valves cause a much
lower risk of blood clotting than mechanical valves. It is generally necessary
to take blood-thinning medicine for only several weeks after valve replacement,
and after that you would take only aspirin. While there is a risk of
complications associated with tissue valve failure or infection, these
complications are relatively rare.
If you need more information, see the topic
Aortic Valve Stenosis.