How does atherosclerosis develop? Who gets it, and why? This deadly process is preventable and treatable.
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.
When bad cholesterol, or LDL, crosses the damaged endothelium, the cholesterol enters the wall of the artery. That causes your white blood cells to stream in to digest the LDL. Over years, cholesterol and cells become plaque in the wall of the artery.
Plaque creates a bump on the artery wall. As atherosclerosis progresses, that bump gets bigger. 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 health problems.
Atherosclerosis usually doesn’t cause symptoms until middle or older age. But as the narrowing becomes severe, it can choke off blood flow and cause pain. Blockages can also rupture suddenly. That’ll cause blood to clot inside an artery at the site of the rupture.
Plaques from atherosclerosis can behave in different ways.
They can stay in 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 in the chest or legs when you exert yourself is the usual symptom.
The plaques of atherosclerosis cause the three main kinds of cardiovascular disease:
Cerebrovascular disease: Ruptured plaques in the brain's arteries cause strokes with the potential for permanent brain damage. Temporary blockages in an artery can also cause something called 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 from plaque causes poor circulation. This makes it painful for you to walk. It’ll also cause wounds not to heal as well. Severe disease may lead to amputations.
Who Gets This?
It might be easier to ask: Who doesn't get atherosclerosis?
It starts early. In autopsies of young soldiers killed in the Korean and Vietnam wars, half to three-quarters had early forms of atherosclerosis.
Even today, a large number of young people without symptoms have evidence of atherosclerosis. A 2001 study of 262 apparently healthy people's hearts may surprise you:
- 52% had some atherosclerosis.
- It was present in 85% of those older than 50.
- 17% of teenagers had it.
No one had symptoms, and very few had severe narrowing 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. Most adults older than 60 have some atherosclerosis but often do not have noticeable symptoms.
Still, rates of death from atherosclerosis have fallen by 25% in the past three decades. This is thanks to better lifestyles and improved treatments.
Atherosclerosis can get worse over time, but it's also preventable. Nine risk factors are to blame for more than 90% of all heart attacks:
- High cholesterol
- High blood pressure
- Abdominal obesity ("spare tire")
- 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 these lowers your odds of cardiovascular disease.
For people at moderate or higher risk -- those who’ve had a heart attack or stroke, or who have angina -- a baby aspirin a day can be important. Aspirin helps prevent clots from forming. Ask your doctor before starting that, as it can have side effects.
Once you have a blockage, 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 risk factors that lead to atherosclerosis will slow or stop the process. That means a healthy diet, exercise, and no smoking. These changes won't remove blockages, but they’re proven to lower the risk of heart attacks and strokes.
Doctors can use invasive techniques to open up blockages from atherosclerosis, or go around them:
Angiographyand stenting: Using a thin tube inserted into an artery in the leg or arm, doctors can get to 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 go around a blocked segment.
These procedures can have complications. They’re usually saved for people with significant symptoms or limitations caused by atherosclerosis.