What Is Atherosclerosis?
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Credit: www.azvascular.com
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Atherosclerosis --
hardening and narrowing of the arteries --
gets a lot of bad press but with good reason. This progressive process silently
and slowly blocks arteries, putting blood flow
at risk.
Atherosclerosis is
the usual cause of heart
attacks, strokes, and peripheral vascular disease -- what together are
called "cardiovascular
disease." Cardiovascular
disease is the No. 1 killer in America, with more than 800,000 deaths
in 2005.
How does
atherosclerosis develop? Who gets it, and why? This deadly process is
preventable and treatable. Read on, and get to know your enemy.
What Causes Atherosclerosis?
First, an
Anatomy 101 review: Arteries are blood vessels that carry blood from the heart throughout
the body. They're lined by a thin layer of cells called the endothelium. The
endothelium works to keep the inside of arteries toned and smooth, which keeps
blood flowing.
According to
experts, atherosclerosis begins with damage to the endothelium caused by high
blood pressure, smoking, or highcholesterol.
That damage leads to the formation of plaque.
When bad cholesterol,
or LDL,
crosses the damaged endothelium, thecholesterol enters
the wall of the artery. That causes your white blood cells to
stream in to digest the LDL.
Over years, the accumulating mess of cholesterol and
cells becomes a plaque in the wall of the artery.
Plaque is a
jumble of cholesterol, cells, and debris that creates a bump on the artery
wall. As atherosclerosis progresses, that bump gets bigger. And when it gets
big enough, it can create a blockage. That process goes on throughout your
entire body. As a result, not only is your heart at risk but you are also at risk
for stroke and
other kinds of health problems.
Atherosclerosis
usually causes no symptoms until middle or older age. But as narrowings become
severe, they choke off blood flow and cancause pain.
Blockages can also suddenly rupture, causing blood to clot inside an artery at
the site of the rupture.
Plaques from
atherosclerosis can behave in different ways.
- They can stay within the artery wall. There, the plaque grows to a certain size and stops. Since this plaque doesn't block blood flow, it may never cause symptoms.
- Plaque can grow in a slow, controlled way into the path of blood flow. Eventually, it causes significant blockages. Pain on exertion (in the chest or legs) is the usual symptom.
- The worst-case scenario consists of plaques that suddenly rupture, allowing blood to clot inside an artery. In the brain, this causes astroke; in the heart, a heart attack.
The plaques
of atherosclerosis cause the three main kinds of cardiovascular
disease:
- Coronary artery disease: Stable plaques in the heart's arteries cause angina (chest pain on exertion). Sudden plaque rupture and clotting causes heart muscle to die. This is a heart attack, or myocardial infarction.
- Cerebrovascular disease: Ruptured plaques in the brain's arteries causes strokes with the potential for permanent brain damage. Temporary blockages in an artery can also cause transient ischemic attacks (TIAs), which are warning signs of stroke; however, there is no brain injury.
- Peripheral artery disease: Narrowing in the arteries of the legs caused by plaque causes poor circulation. This causes pain on walking and poor wound healing. Severe disease may lead to amputations.
Who Gets
Atherosclerosis?
It might be
easier to ask, who doesn'tget atherosclerosis?
Atherosclerosis
starts early. In autopsies of young American soldiers killed in action in the
Korean and Vietnam wars, half to three-quarters had early forms of
atherosclerosis.
Even today,
a large number of asymptomatic young people have evidence of atherosclerosis. A
2001 study of 262 apparently healthy people's hearts may surprise you:
- 52% had some atherosclerosis.
- Atherosclerosis was present in 85% of those older than 50.
- 17% of teenagers had atherosclerosis.
No one had
symptoms, and very few had severe narrowings in any arteries. This was very
early disease, detectable only by special tests.
If you are
40 and generally healthy, you have about a 50% chance of developing serious
atherosclerosis in your lifetime. The risk goes up as you get older. The
majority of adults older than 60 have some atherosclerosis but often do not
have noticeable symptoms.
There is
good news. Rates of death from atherosclerosis have fallen by 25% since 30
years ago. This is thanks to both better lifestyles and improved treatments.
Atherosclerosis Prevention
Atherosclerosis
is progressive, but it's also preventable. For example, nine risk factors are
to blame for upwards of 90% of all heart attacks:
- Smoking
- High cholesterol
- High blood pressure
- Diabetes
- Abdominal obesity ("spare tire")
- Stress
- Not eating fruits and vegetables
- Excess alcohol intake (more than one drink for women, one or two drinks for men, per day)
- Not exercising regularly
You may
notice all of these have something in common: You can do something about them!
Experts agree that reducing your risk factors leads to a lower risk of cardiovascular
disease.
For people
at moderate or higher risk -- those who’ve had a heart attack or stroke,
or who suffer angina -- taking a baby aspirin a
day can be important. Aspirin helps prevent clots from forming. Ask your doctor
before starting daily aspirin, as it can have side effects.
Atherosclerosis Treatment
Once a
blockage has developed, it's generally there to stay. With medication and
lifestyle changes, though, plaques may slow or stop growing. They may even
shrink slightly with aggressive treatment.
- Lifestyle changes: Reducing the lifestyle risk factors that lead to atherosclerosis will slow or stop the process. That means a healthy diet, exercise, and no smoking. These lifestyle changes won't remove blockages, but they’re proven to lower the risk of heart attacks and strokes.
- Medication: Taking drugs for high cholesterol and high blood pressure will slow and perhaps even halt the progression of atherosclerosis, as well as lower your risk of heart attacks and stroke.
Using
invasive techniques, doctors can also open up blockages from atherosclerosis,
or go around them:
- Angiography and stenting: Cardiac catheterization with angiography of the coronary arteries is the most common angiography procedure performed. Using a thin tube inserted into an artery in the leg or arm, doctors can access diseased arteries. Blockages are visible on a live X-ray screen. Angioplasty (catheters with balloon tips) and stenting can often open up a blocked artery. Stenting helps to reduce symptoms, although it does not prevent future heart attacks.
- Bypass surgery: Surgeons "harvest" a healthy blood vessel (often from the leg or chest). They use the healthy vessel to bypass a segment blocked by atherosclerosis.
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