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There are four valves in the heart. What heart valves do is they open and close and when
the heart beats, generally the heart valve opens, then when the heart relaxes, the valve
closes and this allows the blood to go in one direction.
The most common valve that we operate on is the aortic valve. This is the aorta. This
is the large artery leading out of the heart and if I were to remove this, under here,
you would see the aortic valve. The aortic valve is the window of the heart.
It's the last valve the blood sees before its ejected out to the body. In the case of
aortic stenosis, thereÕs a blockage in the valve and the valve has trouble opening.
You can't ususally replace the aortic valve because itÕs typically heavily calcified.
We need to replace the valve and we do that by cutting out the valve and replacing with
a prosthetic valve. There are two choices of prosthetic valves. Basically, thereÕs
mechanical valves and there are biological valves. The mechanical valves are made out
of a phosphorylated carbon compound. The white cloth is where we place our sutures and thatÕs
how we implant it into the heart. In this case, its what we call a bi-leaflet valve.
In this case when we open you can see there are two leaflets. When it closes the leaflets
come together like that. The mechanical valve or people often refer to it as the metal valve,
lasts pretty much forever. ThatÕs a great thing but there are a couple downsides to
the mechanical valve. The one is they can often have a clicking sound so on a patient
who is thin, you may actually hear the valve clicking. The other thing is the mechanical
valve requires blood thinners like Coumadin for the rest of your life. Now Coumadin is
a pill you would take once a day and once a month you would have to have your blood
tested to make sure your blood is adequately thinned. The other option is a series of biological
valves: the two most common biological valves are the pig valve or porcine and cow valve
or bovine valve. This is an example of the pig valve or porcine and this is an example
of the bovine or cow valve. WhatÕs interesting is that the pig valve is literally the pigÕs,
valve. The company harvests the valve of the pig and creates this stent around it so youÕre
actually using the pigÕs valve. The white part again is the sewing cuff and you can
see the valve tissue inside. The cow valve is not actually the cowÕs valve. It is cow
pericardium which is the lining around the heart that they make into a valve, in other
words, you can think of it as small pieces of leather that is made into a valve. It just
happens to be made out of a cow. So, whatÕs the difference? Well both are very good. The
advantage of a biological valve is you do not need any blood thinners except maybe a
baby aspirin each day. The biological valves do not make any clicking sound. The downside
of a biological valve is that it might not last forever so we typically will put these
valves in patients who are 65 years of age or older, and particularly in patients who
are 70 and older and we believe, we hope in patients who are 65 or 70 years old and up,
that it will last maybe 15 or 20 years. Well the good news is that nowadays if a biological
valve doesnÕt last 15 or even 20 years, we have a new procedure known as TAVR or transcatheter
aortic valve replacement where we can actually leave the old bioprosthetic valve in place
and put a new one in with catheter techniques. Now that technology is evolving but its fair
to say that patients with bioprosthetic valves that wear out, most likely wonÕt need a second
open procedure; likely they can be treated with the new TAVR or transcather aortic valve
procedure.