Arteries & circulation
Atherosclerosis
What is atherosclerosis?
Atherosclerosis is a disease caused by the build-up of plaque on the interior walls of our arteries.
Most of us think of plaque as a kind of fatty or waxy substance but, in reality, it’s a living tissue that forms on the artery lining in response to inflammation and irritation. It has a core made of cholesterol, fats, calcium, and dead cells, and an overlying fibrous cap.
Plaque stiffens and narrows the arteries and restricts the flow of blood. It can also rupture or cause blood clots, and the clots or plaque fragments can then completely block blood flow, leading to a heart attack, stroke, or other serious complication.
Atherosclerosis is extremely common. A famous autopsy study involving 300 U.S. soldiers who were killed in the Korean War (1950-53) found that 77% of them had atherosclerosis, even though their average age was only 22 years old. This finding has been validated by numerous other studies since 1953.
The US soldiers’ atherosclerosis would have been entirely asymptomatic at that stage but, had these young men lived to reach their 60s or 70s, many of them would have begun to experience problems.
Atherosclerosis can affect any artery in your body, and its impact on your health will vary depending on which arteries are involved.
Typically, you won’t experience any symptoms until your arteries have become significantly narrowed or blocked by plaque.
Atherosclerotic plaque narrowing an artery
Which arteries are most affected by atherosclerosis?
Coronary arteries / Coronary artery disease
Your coronary arteries supply blood to your heart muscle, and if they become atherosclerotic and narrow, you will experience all of the classic signs of heart problems – shortness of breath, chest pain, an irregular heartbeat, and others.
Atherosclerosis of the coronary arteries is commonly referred to as coronary artery disease.
For more information about coronary artery disease, and the pain it can cause (which is called angina), take a look at our Angina section.
Atherosclerosis of the coronary arteries
The aorta
Your aorta is your largest artery. It carries blood from your heart down to your pelvis. Atherosclerotic plaque can build up anywhere along its length but it is often most severe in your abdominal aorta – at the level of your belly.
Because the aorta is such a large blood vessel, the narrowing effect of atherosclerosis isn’t usually significant, but atherosclerotic plaque can weaken the artery walls, which can put you at risk of developing an aneurysm, or bulge, in your aorta. Ruptured aneurysms are very often fatal.
Atherosclerosis of the aorta
Carotid arteries
Your carotid arteries run up both sides of your neck and carry blood to your head and brain.
If your carotids are narrowed by atherosclerotic plaque you may experience TIAs (transient ischemic attacks). TIAs occur when small blood clots that form on the surface of the plaque break off and travel to your brain, causing a temporary blockage. TIAs are like mini-strokes that resolve by themselves.
If the plaque ruptures, it can cause a stroke.
Atherosclerosis of the carotid arteries
Renal arteries
Your kidneys are supplied with blood by your renal arteries. If their blood supply is partially cut off by plaque, you may develop chronic kidney disease, and this, ultimately, can become kidney failure.
Often, the first symptom of atherosclerotic narrowing of the renal arteries is uncontrollable high blood pressure.
Stents can be used to reopen blocked renal arteries and relieve symptoms.
Atherosclerosis of the renal arteries
Peripheral arteries / Peripheral artery disease
Your peripheral arteries supply blood to your arms, legs, and pelvis. Atherosclerotic narrowing and blockages cause what is commonly known as peripheral artery disease.
Classic symptoms of peripheral artery disease are cramps in the calf muscles, and sometimes in the buttocks.
Leg cramps caused by peripheral artery disease are not the same as the leg cramps you might get at night in bed. The key difference is that they happen when you’re exercising and are relieved as soon as you stop and rest.
If peripheral arterial plaque ruptures it can completely block blood flow. This must be treated urgently; a blockage of more than about 12 hours will put you at risk of losing a limb.
Atherosclerosis of the peripheral arteries
What causes atherosclerosis?
Atherosclerosis has no single, easy-to-identify cause; it is the end result of lots of different factors, many of them involving lifestyle.
A diet that is high in animal fats, tropical oils (like palm oil and coconut oil, which are used in many processed foods), salt, and sugar increases your risk. So do a sedentary lifestyle and the weight gain that often goes hand-in-hand with it.
Diabetes is another known risk factor, so if you have either type 1 or type 2 diabetes, you should be especially careful about managing your other atherosclerosis risks.
Hypertension increases your risk of developing atherosclerosis because the abnormally high pressure of the blood in your arteries causes scarring, and the arterial scar tissue is susceptible to the build-up of plaque.
A related risk factor is smoking. Nicotine raises your blood pressure and is toxic to the lining of your arteries, and both of these factors encourage the formation of atherosclerotic plaques. And because it’s the nicotine that’s the problem, vaping and smokeless tobacco are guilty as charged, too.
Finally, age and family history play their part. If you’re over 60 you’re likely to already have some atherosclerosis.
Inherited disorders like familial hypercholesterolemia, where the body is unable to properly regulate cholesterol levels, can contribute significantly to risk.
Common causes of atherosclerosis include:
- Diet: Animal fats, tropical oils like palm and coconut oil, salt, sugar, and processed foods all contribute to your risk of developing atherosclerosis
- Smoking
- Lack of exercise
- Drinking too much alcohol
- Being overweight
- Hypertension
- Age: Being over 60 years old is a risk factor
- Genetic factors, like familial hypercholesterolemia
What are the symptoms of atherosclerosis?
Until you have significant narrowing of your arteries, or you experience a plaque rupture or clot, you may be completely unaware that you have atherosclerosis. Mild to moderate disease causes no symptoms and you can continue in this state for a very long time, decades even.
If you do experience symptoms, they will vary depending on the location of the atherosclerosis that is causing them.
– Aorta: There are few direct symptoms unless you develop serious complications, such as an aneurysm
– Coronary arteries: Chest pain (angina), shortness of breath on exercise.
– Carotid arteries: TIAs (transient ischemic attacks), which occur when small blood clots temporarily block blood flow to the brain
– Renal arteries: High blood pressure.
– Peripheral arteries: Leg, and sometimes buttock, cramps on exertion that are relieved by rest. Non-healing skin ulcers are another symptom.
Atherosclerotic plaques in any of these locations can rupture or cause a blood clot. If the plaque or clot travels to your heart, it can cause a heart attack. If it travels to your brain, it can cause a stroke.
How is atherosclerosis treated?
Treatment options for atherosclerosis center on lifestyle changes, medications (particularly statins, which lower cholesterol levels and reduce inflammation), and – if necessary – surgery to reopen clogged blood vessels.
- Lifestyle changes: Improve your diet (restrict animal fats, red meat, tropical oils, salt, sugar, and processed foods), exercise more, drink less alcohol, quit smoking
- Medication: Medications can lower your cholesterol level (statins), manage your blood sugar (if diabetes is a contributing factor), control hypertension, and prevent blood clots
- Surgery: A transcatheter procedure can be used to stent areas of acutely narrowed vessels. Surgery to bypass blocked coronary arteries is a final option
What are the aims of treatment?
The aims of treatment are to reverse or stabilize your atherosclerosis, manage your symptoms, and prevent you from having a stroke or heart attack.