Cholesterol plaques can be the cause of heart disease. Plaques begin in artery walls and grow for years, slowly blocking blood flow in the arteries. Worse, a cholesterol plaque can rupture. The sudden blood clot that forms over the rupture then causes a heart attack or stroke.
Blocked arteries caused by plaque buildup and blood clots are the leading cause of death in the U.S. Reducing cholesterol and other risk factors can help prevent cholesterol plaques from forming. Occasionally, it can even reverse some plaque buildup.
Cholesterol Plaques and Atherosclerosis
Cholesterol plaques form by a process called atherosclerosis. It’s also called "hardening of the arteries." LDL, or "bad cholesterol," is the raw material of cholesterol plaques. It can damage the arteries that carry blood from your heart to the rest of your body. Then, once the damage has started, LDL keeps on building up in the artery walls. Progressive and painless, atherosclerosis grows cholesterol plaques silently and slowly.
The cholesterol plaques of atherosclerosis are the usual cause of heart attacks, strokes, and peripheral arterial disease. These conditions together are major contributors to cardiovascular disease. Cardiovascular disease is the No. 1 killer in America, causing about 650,000 deaths each year.
Understanding Cholesterol Plaque
Cholesterol plaques start developing in the walls of arteries. Long before they can be called plaques, hints of atherosclerosis can be found in the arteries. Even some teens have these "fatty streaks" of cholesterol in their artery walls. These streaks are early precursors of cholesterol plaques. They can't be easily spotted by tests. But researchers have found them during autopsies of young victims of accidents and violence.
Atherosclerosis develops over years. It happens through a complicated process that involves:
- Damaged endothelium. The smooth, delicate lining of blood vessels is called the endothelium. High cholesterol, smoking, high blood pressure, or diabetes can damage the endothelium, creating a place for cholesterol to enter the artery's wall.
- Cholesterol invasion. "Bad" cholesterol (LDL cholesterol) circulating in the blood crosses the damaged endothelium. LDL cholesterol starts to gather in the wall of the artery.
- Plaque formation. White blood cells stream in to digest the LDL cholesterol. Over years, the toxic mess of cholesterol and cells becomes a cholesterol plaque in the wall of the artery.
How Cholesterol Plaque Attacks
Once established, cholesterol plaques can behave in different ways.
- They can stay within the artery wall. The cholesterol plaque may stop growing or may grow into the wall, out of the path of blood.
- Plaques can grow in a slow, controlled way into the path of blood flow. Slow-growing cholesterol plaques may or may not ever cause any symptoms, even with severely blocked arteries.
- Cholesterol plaques can suddenly rupture, the worst-case scenario. This will allow blood to clot inside an artery. In the heart, this causes a heart attack. In the brain, it causes a stroke.
Cholesterol plaques from atherosclerosis cause the three main kinds of cardiovascular disease:
- Coronary artery disease. Stable cholesterol plaques in the heart's arteries can cause no symptoms or can cause chest pain called angina. Sudden cholesterol plaque rupture and clotting cause blocked arteries. When that happens, heart muscle dies. This is a heart attack, also called myocardial infarction.
- Cerebrovascular disease. Cholesterol plaque can rupture in one of the brain's arteries. This causes a stroke, leading to permanent brain damage. Blockages can also cause transient ischemic attacks, or TIAs. A TIA has symptoms like those of stroke. But they are temporary, and there is no permanent brain damage. Patients who have a TIA are at a much higher risk of a later stroke, so medical attention is essential.
- Peripheral arterial disease (PAD). Blocked arteries in the legs can cause pain when you walk. They also bring about poor wound healing because of poor circulation. Severe disease may lead to amputations.
Preventing Cholesterol Plaques
Atherosclerosis and cholesterol plaques are progressive, meaning they get worse with time. They are also preventable. Nine risk factors are to blame for up to 90% of all heart attacks:
- High cholesterol
- High blood pressure
- Abdominal obesity ("spare tire")
- Not eating many fruits and vegetables
- Drinking too much alcohol: more than one drink per day for women or more than one or two drinks per day for men
- Not getting regular physical activity
You may notice that almost 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 heart disease.
For people at higher risk from cholesterol plaques, taking a baby aspirin a day can be important. Aspirin helps prevent clots from forming. Ask your doctor before starting aspirin, as it can have side effects.
Shrinking Cholesterol Plaques
Once a cholesterol plaque is there, it's generally there to stay. With treatment, though, plaque buildup may slow or stop.
Some evidence shows that with strong treatment, cholesterol plaques can even shrink slightly. In one major study, cholesterol plaques shrank 10% in size after a 50% reduction in blood cholesterol levels.
The best way to treat cholesterol plaques is to keep them from forming or progressing. That can be done with lifestyle changes and, if needed, medication.
Drugs and Lifestyle Changes to Cut the Chance of Having Atherosclerosis
Reducing the risk factors that lead to atherosclerosis will slow or stop the process. Ways to lower the amount of cholesterol in your body involve taking cholesterol and blood pressure medications, eating a healthy diet, getting frequent exercise, and not smoking. These treatments won't unclog arteries. But they do lower the risk of heart attacks and strokes.
Here is some advice that can help you improve your cholesterol level and reduce the risks that come with atherosclerosis:
- Exercise, with or without weight loss, increases "good" HDL cholesterol and reduces the risk of heart attacks and strokes.
- A diet high in fiber and low in fats can lower "bad" LDL cholesterol.
- Oily fish and other foods high in omega-3 fatty acids can raise “good” HDL cholesterol.
- If you know or think your cholesterol is high, or if you have a family history of high cholesterol, talk to your doctor about ways you can lower it.
Certain drugs can lower cholesterol levels.
Statins are the most frequently prescribed cholesterol-lowering drugs. They can dramatically lower "bad" LDL cholesterol by 60% or more. They can also increase HDL. Studies have shown that statins can reduce the rates of heart attacks, strokes, and death from atherosclerosis.
Taking a statin for a year or longer can even slightly shrink plaques that cause atherosclerosis. This reversal of atherosclerosis surprised many experts who believed it couldn’t be done.
Completely reversing it isn't possible yet. But taking a statin can reduce the risk of complications from atherosclerosis. The statin fights inflammation, which stabilizes the plaque. For this reason, statins are often key to treating atherosclerosis.
To be effective, statins need to be part of a larger personalized strategy that you and your doctor work out together. Among other things, that strategy will be based on your level of risk for heart attack and stroke as well as your own lifestyle choices.
Fibrates are drugs that reduce triglyceride levels. Fibrates also slightly increase HDL. There are two fibrates used in the U.S.:
Many people have uncomfortable skin flushing that prevents them from taking niacin. (Be wary of "no-flush" over-the-counter preparations; many lack the active form of niacin.) Niacin also can increase blood sugar levels. This is a problem especially for people with diabetes.
Because of its side effects, niacin is much less often prescribed than statins or fibrates.
Bile acid sequestrants
Bile acid sequestrants bind to bile acids in the intestines. This leads to a lower bile acid level. You need bile, so when that happens, cholesterol must be used to make more. This lowers blood cholesterol levels. The bile acid sequestrants include:
Other drugs for lower cholesterol
Ezetimibe (Zetia). This drug works by reducing absorption of cholesterol in the intestines. It can lower LDL levels. But it doesn’t work as well as statins. This drug is usually used in addition to a statin to further lower bad cholesterol. There is no evidence that it reduces the risk of heart attacks or strokes.
Plant sterols. These are taken as supplements in pill form or in foods like margarine. Getting plant sterols every day can reduce cholesterol modestly, about 10%.
Alirocumab (Praluent) and evolocumab (Repatha). These are included in a new class of drugs called proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors. They are for use by people who can’t control their cholesterol through diet and statin treatments. For those with established cardiovascular disease, evolocumab has also proved to be effective in significantly reducing the risk of heart attacks and strokes.
Drugs to reduce high blood pressure
Lowering blood pressure lowers the risk of atherosclerosis and its complications. Diet and exercise alone don't usually bring high blood pressure down to the safe range. Most people with high blood pressure will need medications (usually at least two) to do the job.
There are many classes of high blood pressure drugs that work in a variety of ways. The choice of medicine isn't as important as the result: getting blood pressure down. Guidelines released in 2017 state that normal blood pressure should be less than 120/80. Blood pressure goals for people being treated for high blood pressure vary according to their other health concerns.
Drugs to reduce the risk of blood clots
Antiplatelets. These blood thinners make blood less likely to clot, which can help prevent heart attacks and strokes. But antiplatelets don't slow down or reverse atherosclerosis.
Aspirin. Plain old aspirin is actually a powerful blood thinner. A baby aspirin a day can reduce the risk of first heart attacks and strokes by about 25%.
Ticagrelor (Brilinta). Ticagrelor is similar to clopidogrel. This drug is less effective if patients take more than 100 milligrams a day of aspirin. A "baby aspirin" has 81 milligrams of aspirin. An FDA "black box" warning tells doctors about the risk of using higher doses of aspirin along with ticagrelor.
Prasugrel (Effient). You take this medicine by mouth with or without food, usually once a day or as directed by your doctor. Your doctor may tell you to take it with a low dose of aspirin.
Warfarin (Coumadin). This powerful blood thinner is an anticoagulant. It is not generally used to treat atherosclerosis. Warfarin is used for other medical conditions that involve blood clots, such as atrial fibrillation and deep vein thrombosis. It has not been shown to be better than aspirin in preventing heart attacks.
The benefits of blood thinners come at the price of an increased risk of bleeding. For most people at risk from atherosclerosis, the benefits of antiplatelets outweigh the risks. Speak with your doctor before you start using aspirin or any other heart medication.
A daily dose of colchicine (0.5 or 0.6 mg) has proved effective in helping prevent atherosclerosis in some patients. Inflammation plays a pivotal role in coronary disease, and this medication, normally used for treating gout, has shown some success because of its anti-inflammatory properties.
There are no proven cures for atherosclerosis. But medication and lifestyle changes can reduce the risk of complications.
Procedures to Unclog Arteries
Using invasive procedures, doctors can see and unclog arteries, or provide a path for blood to go around blocked arteries. Treatments include:
- Angiography, angioplasty, and stenting. Using a catheter put into an artery in the leg or arm, doctors can enter diseased arteries. This procedure is called cardiac catheterization. Blocked arteries are visible on a live X-ray screen. A tiny balloon on the catheter can be inflated to compress cholesterol plaque in the blocked arteries. Placing small tubes called stents helps to keep open blocked arteries. The stent is usually made of metal and is permanent. Some stents have medicine that helps keep the artery from getting blocked again.
- Bypass surgery. Surgeons harvest a healthy blood vessel from the leg or chest. They use the healthy vessel to bypass blocked arteries.
These procedures involve a risk of complications. They are usually saved for people with significant symptoms or limits caused by the cholesterol plaques of atherosclerosis.