Atherosclerosis is not only a tongue twister;
it’s the leading cause of heart attacks worldwide.
Understanding how this disease can lead to an attack starts with knowing how your immune
system works for and against you.
The good news is that thanks to medical advancements, people are living longer and surviving in
the face of this disease.
- So there's really good news on the horizon for atherosclerosis.
We are increasingly understanding the disease.
My name is DeLisa Fairweather.
I'm a PhD researcher in Jacksonville, Florida, working at Mayo Clinic.
I've been studying heart disease for around 25 years.
Atherosclerosis is a very long name that's difficult to pronounce.
So it really refers to “athero-,” which talks about the vessels in our heart, and
“sclerosis,” which means fibrosis of those vessels.
And it is one of the most common heart diseases around the world.
And what happens is inflammation goes into the vessel wall and accumulates there, and
we call that a plaque.
Plaque and atherosclerosis is caused by inflammation, and the inflammation is really trying to regulate
a problem.
And the problem is that we have too much cholesterol.
Cholesterol is a type of fat made by our liver, and that we get in part from our food.
There are two main types of cholesterol: “good cholesterol,” HDL,
and “bad cholesterol,” LDL.
The good cholesterol helps keep the bad cholesterol in check, but, if there’s an imbalance,
the bad cholesterol can build up on the walls of your arteries, increasing your risk of
a heart attack.
One way to think of the arteries around your heart is like pipes.
And when those pipes get filled with bad cholesterol, it can create a kind of clog.
The body’s immune cells then come along and try to clear up the fat, absorbing it
into themselves.
- The immune system is really important in this process because it is going in and is
trying to repair the damage.
On the one hand, it's trying to repair the damage; on the other hand it contributes to
the damage.
And you can kind of think of it as if you had a bomb, and you wanted to try to protect
it, but you couldn't remove the bomb, what would you do?
Well, you would want to try to create a protective covering so that it could not cause damage.
And that's what the immune cell, the macrophage, tries to do and it takes the fat inside its
body.
It accumulates all of that fat.
So it ends up looking like what we call a “foam cell,” all full of the fat molecules.
This foaming process creates a backlog of these fatty immune cells which clog the vessel
wall, with more and more cells clogging that pipe and creating a problem with blood flow.
This often presents as high blood pressure, which means the blood is trying to get through
this small area of the vessel.
This can lead to a rupture.
- And when the rupture happens, then everything is released.
It ends up in a clot, and you can have a heart attack, or that clot can break free and become
loose and travel through your vessels, and cause a stroke if it goes to your brain.
All of this so far is “atherosclerosis,” but this form of heart disease is most commonly
linked to heart attacks.
So what is a heart attack exactly?
- So what is happening when you have a heart attack is that the conditions have all come
to this perfect storm
and what happens with a heart attack is the vessel wall has inflammation that ends up
in what we call a plaque.
And that plaque buildup then can burst open and clog the artery and
that then causes a heart attack.
It completely stops up the vessel.
And when that happens, the blood flow's cut off to that area of your heart and when the blood
flow's cut off, then the cells in that area will start to die.
So the technical term is a myocardial infarct.
We most commonly call it a heart attack.
Symptoms of a heart attack include pain down the left side of your arm, shortness of breath,
and nausea - and these are all associated with that cutoff of blood flow to the heart.
Then what's happening inside the heart is that when that blood flow's cut off, it is
needed to provide energy and life to those cells in your heart and those cells start
to die very rapidly and cause heart damage.
Risk factors for atherosclerosis and heart attacks include things that you can control
like smoking, diet, and high cholesterol - and some you can’t control, like age.
- An important risk factor is if you're male, especially younger, middle-aged male, you
have a higher risk factor; as you age, for women, the risk factor of having atherosclerosis
comes after menopause and actually when you're much older, maybe around age 70, and that's
because estrogen really protects you from having a heart attack when you're younger.
Fortunately, there have been exciting new developments in the area of understanding
this disease and preventing it.
- Really the statistics are wonderful that we are preventing people from dying.
So even though you might have the clot, we're able to go in and remove the clot very rapidly
when someone has a heart attack and put in what's called a stent.
And this just holds this area open.
And that technology is improving every year, so that people can live after having these
heart attacks, a really great life and a full life.
And we're making great inroads, so that this disease is not killing nearly as many people
as it used to.