Atherosclerosis is a potentially serious condition where arteries become clogged up by fatty substances known as plaques or atheroma.
The plaques cause affected arteries to harden and narrow, which can be dangerous as restricted blood flow can damage organs and stop them functioning properly.
If a plaque ruptures, it can cause a blood clot. This can block the blood supply to the heart, triggering a heart attack, or it can block the blood supply to the brain, triggering a stroke.
Cardiovascular disease (CVD)
Atherosclerosis is a major risk factor for many conditions involving the flow of blood.
Collectively, these conditions are known as cardiovascular disease (CVD). Examples include:
- peripheral arterial disease – where the blood supply to your legs is blocked, causing muscle pain
- coronary heart disease – the coronary arteries (the main arteries that supply your heart) become clogged with plaques
- stroke – where the blood supply to your brain is interrupted
- heart attack – where the blood supply to your heart is blocked
Read more about atherosclerosis and cardiovascular disease.
What causes atherosclerosis?
Exactly how arteries become clogged is still unclear, although the following things increase your risk of atherosclerosis:
- a high-fat diet
- lack of exercise
- being overweight or obese
- having either type 1 or type 2 diabetes
- having high blood pressure (hypertension)
- having high cholesterol
Read more about causes and risk factors for atherosclerosis.
Treatment for atherosclerosis aims to prevent the condition from worsening to the point that it can trigger a serious cardiovascular disease, such as a heart attack.
This can be achieved by making lifestyle changes, such as eating a healthier diet and increasing exercise, as well as using certain medications such as ACE inhibitors to treat high blood pressure, or statins to lower cholesterol levels.
In some cases, surgery may be required to widen or bypass a section of a blocked or narrowed artery.
Read more about the treatment of atherosclerosis.
Who is affected?
It is hard to estimate how common atherosclerosis is, although it is suspected that almost all adults have the condition to some degree.
Your arteries naturally get harder as you grow older, so atherosclerosis tends to be more common in people aged over 40.
Atherosclerosis is more common in men than women, possibly because hormones used in the female reproductive cycle, such as oestrogen, provide some protection against the effects of the condition.
The public health impact of atherosclerosis
Atherosclerosis (and the resulting cardiovascular diseases) is the single biggest cause of death in the developed world, accounting for one in three of all deaths.
Each year an estimated 124,000 deaths are caused by cardiovascular disease in England and Wales. Around 39,000 of these deaths occur in people under 75 years.
For every death, cardiovascular disease causes two non-fatal but serious complications, such as a stroke or heart attack.
It is expected that atherosclerosis will continue to be a major health problem in this country because of the ongoing obesity epidemic.
Symptoms of atherosclerosis
Atherosclerosis does not usually produce symptoms until your blood circulation becomes restricted or blocked, leading to cardiovascular disease (CVD).
The type of cardiovascular disease and its associated symptoms depends on where the blockage occurs.
Conditions caused by atherosclerosis include:
- peripheral arterial disease
- heart attack
The conditions and their symptoms are described below.
Peripheral arterial disease
Peripheral arterial disease, also known as peripheral vascular disease, is a condition that occurs when there is a blockage in the arteries of your limbs (in most cases, your legs).
The most common symptom of peripheral arterial disease is pain in your legs. This is usually in one or both of your thighs, hips, or calves.
The pain can feel like a cramp, or a sensation of dullness or heaviness in the muscles of your legs. The pain usually comes and goes and is worse when doing exercise that uses your legs, such as walking or climbing stairs.
Other symptoms of peripheral arterial disease include:
- weakness or numbness in your legs
- having sores on your feet or legs that never heal
- a change in the colour of the skin on your legs
- hair loss on your legs or feet
- thickening of your toenails
- erectile dysfunction, also known as impotence
Angina is caused by a reduced blood supply to the heart.
The most common symptom of angina is a feeling of pain or discomfort in your chest. The pain can feel tight, dull or heavy, and usually passes within a few minutes.
The pain can spread from your chest to your left arm, neck, jaw and back. It usually follows a period of physical activity or emotional stress. In some cases, the pain can develop during cold weather or after eating a meal.
Some people with angina may also experience:
- feeling sick
- fatigue (feeling tired all the time)
- belching (burping)
Angina symptoms are sometimes referred to as an angina attack.
If atherosclerosis weakens the walls of your blood vessels, it can lead to the formation of an aneurysm (a bulge in a blood vessel).
If the aneurysm grows too large, there is a danger it will rupture, which can cause potentially fatal internal bleeding and organ damage.
An aneurysm can develop anywhere in the body, but the two most common types of aneurysm are:
- a brain aneurysm (also known as a cerebral aneurysm), which develops inside the brain
- an aortic aneurysm, which develops inside the aorta (a large blood vessel that runs down the abdomen and transports blood away from your heart)
If an aortic aneurysm ruptures, you will experience a sudden and severe pain in the middle or side of your abdomen. In men, the pain can spread down into the scrotum (the sac containing the testicles).
Symptoms of a ruptured brain aneurysm usually begin with a sudden and severe headache, which has been described as like being hit on the head.
You should dial 999 immediately to request an ambulance if you suspect a ruptured aneurysm.
If one of the plaques in your coronary arteries ruptures, it could create a blood clot. If the blood clot blocks the supply of blood to your heart, it will cause you to have a heart attack.
Symptoms of a heart attack include:
- chest pain – usually located in the centre of your chest and giving the sensation of pressure, tightness or squeezing
- pain in other parts of the body that can feel as though it is travelling from your chest to your arms (usually the left arm, although both arms can be affected), jaw, neck, back and abdomen
- an overwhelming sense of anxiety (similar to a panic attack)
- shortness of breath
- feeling sick
You should dial 999 immediately if you suspect a heart attack.
Blood clots can also block the supply of blood to your brain, causing a stroke.
The main symptoms of a stroke can be remembered by using the acronym FAST, which stands for:
- Face – the face may have fallen on one side, the person may be unable to smile, or their mouth or eye may have drooped
- Arms – because of a weakness or numbness of the arms, the person with a suspected stroke may not be able to raise both their arms and keep them raised
- Speech – the person’s speech may be slurred
- Time – it is time to dial 999 immediately if you see any of these signs or symptoms
Symptoms in the FAST test are successful in identifying about 90% of all strokes.
You should dial 999 immediately to request an ambulance if you suspect a stroke.
Other signs and symptoms may include:
- communication problems (difficulty talking and understanding what others are saying)
- problems with balance and co-ordination
- difficulty swallowing
- severe headaches
- numbness or weakness resulting in complete paralysis in one side of the body
- loss of consciousness (in severe cases)
A transient ischaemic attack (TIA) is where the blood supply to the brain is temporarily interrupted, causing a “mini-stroke”.
The symptoms of a TIA are the same as those of a stroke, but they only last for between a few minutes and a few hours before disappearing completely.
However, a TIA should never be ignored as it is a serious warning sign that there is a problem with the blood supply to your brain.
Causes of atherosclerosis
As you get older, it’s thought that your arteries naturally begin to harden and narrow.
However, a number of things can accelerate this process. These are described below.
High-fat diets and cholesterol
Cholesterol is a type of fat that is essential for the functioning of the body. It helps to produce hormones, make up cell membranes (the walls that protect individual cells) and protect nerve endings.
There are two main types of cholesterol:
- low-density lipoprotein (LDL)
- high-density lipoprotein (HDL)
If you eat foods high in saturated fat, this can lead to high levels of LDL (known as “bad cholesterol”).
LDL carries cholesterol from your liver to the cells that need it. If there is too much cholesterol for the cells to use, it can build up in the artery walls.
This leads to fatty deposits which, over time, reduce or completely block your blood supply. The fatty deposits are also known as plaques or atheroma.
Foods high in saturated fat include:
- processed meat
A lack of regular exercise, being obese and drinking excessive amounts of alcohol can also increase the levels of LDL cholesterol in your body.
Smoking can damage the walls of your arteries. Blood cells known as platelets will then clump together at the site of the damage to try to repair it. This can cause your arteries to narrow.
Smoking also decreases the blood’s ability to carry oxygen around your body, which increases the chances of a blood clot occurring.
Read more about the health risks associated with smoking.
High blood pressure
If you have high blood pressure (hypertension), it will damage your arteries in the same way as cigarette smoke.
Your arteries are designed to pump blood at a certain pressure. If that pressure is exceeded, the walls of the arteries will be damaged.
High blood pressure can be caused by:
- being overweight
- drinking excessive amounts of alcohol
- a lack of exercise
Read more about high blood pressure.
If you have poorly controlled type 1 or type 2 diabetes, the excess glucose in your blood can damage the walls of your arteries.
Being overweight or obese does not directly increase your risk of developing atherosclerosis and cardiovascular disease (CVD), but it does lead to related risk factors that do raise your risk.
In particular, overweight or obese people:
- have an increased risk of developing high blood pressure
- tend to have higher levels of cholesterol as a result of eating a high-fat diet
- have an increased risk of developing type 2 diabetes
Read more about obesity.
Drinking an excessive amount of alcohol can cause high blood pressure (hypertension) and raised blood cholesterol levels, increasing your risk of developing atherosclerosis and cardiovascular disease.
Read more about alcohol misuse.
If you have a first-degree relative (a parent, brother or sister) with atherosclerosis and cardiovascular disease, you are twice as likely to develop similar problems compared with the rest of the population.
Rates of high blood pressure and diabetes are higher among people of African and African-Caribbean descent.
This means people in this group also have an increased risk of developing atherosclerosis and cardiovascular disease.
People of south Asian descent (those from India, Bangladesh, Pakistan and Sri Lanka) are five times more likely to develop diabetes than the population at large.
Again, this increases the risk of people in this group developing atherosclerosis and cardiovascular disease.
Recent research suggests that air pollution, in particular traffic pollution, can speed up the progression of atherosclerosis.
As atherosclerosis does not cause symptoms until cardiovascular disease occurs, those at risk of developing the condition should be tested.
Screening allows treatment to be given to reduce the risk of cardiovascular disease developing.
Your GP may recommend you are screened if you:
- are over 40 years of age – everyone between the ages of 40 and 74 will be automatically invited to have an NHS Health Check
- are overweight or obese
- are a smoker or have a history of heavy smoking
- eat a high-fat diet
- have high blood pressure (hypertension)
- have type 1 or type 2 diabetes
- have a family history of heart disease, high blood pressure or diabetes
There are several tests that assess your level of existing atherosclerosis and your risk of developing cardiovascular disease, including:
- blood tests – to measure the amount of cholesterol in your blood and the amount of glucose, if you are diabetic
- blood pressure tests
- a measurement of your weight and waist size
Your GP may also carry out an ankle-brachial index test. This compares the blood pressure in your ankle to the blood pressure in your arm.
A difference between the two readings may suggest that atherosclerosis is restricting the blood supply to your legs and that you have peripheral arterial disease.
If your risk of developing cardiovascular disease is high or you are experiencing symptoms of cardiovascular disease, further tests may be needed to confirm the level of atherosclerosis and locate any potential blockages in your arteries. These tests are explained below.
An electrocardiogram (ECG) measures the electrical activity of your heart. This test can measure how well your heart is functioning and can often detect the presence of heart disease.
An ultrasound scanner uses sound waves to build up a picture of the inside of your body. This can be used to measure your blood pressure at different points in your body. Any variation in pressure could point to the site of a blockage in your arteries. Ultrasound tests can also be used to study the larger arteries.
Read more about ultrasound scans.
During an angiography you are injected with a special dye that can be seen on X-ray. The test is used to see how the blood flows through your body.
Read more about angiographies.
Computerised tomography scan
A computerised tomography (CT) scan takes a series of X-ray images and uses a computer to assemble them into a more detailed three-dimensional image. It can often detect narrowing or hardening in the larger arteries.
Read more about CT scans.
An ophthalmoscopy is a type of eye test where an instrument called an ophthalmoscope is used to examine the blood vessels in the back of your eye. The ophthalmoscope can sometimes detect hardening of the blood vessels in your retina (the retina is the light-sensitive layer at the back of the eye).
If you are at risk of developing a cardiovascular disease (CVD) as a result of atherosclerosis, you will be advised to change your lifestyle to reduce this risk.
Lifestyle changes include changing your diet and taking more exercise. Read more about preventing atherosclerosis-related cardiovascular disease.
There are several medications available to treat many of the underlying causes of atherosclerosis, such as a high cholesterol level and high blood pressure (hypertension).
Depending on your individual circumstances, you may only need to take one medication, or you may need a combination of different medications.
High blood pressure (hypertension)
The most widely used medications for treating high blood pressure are outlined below.
Angiotensin-converting enzyme (ACE) inhibitors
Angiotensin-converting enzyme (ACE) inhibitors work by blocking the actions of some of the hormones that help regulate blood pressure.
By stopping these hormones from working, ACE inhibitors reduce the amount of water in your blood as well as widening your arteries, both of which will lower your blood pressure.
ACE inhibitors are not suitable for:
- pregnant or breastfeeding women
- people with conditions that affect the blood supply to their kidneys
- those with a history of heart disease
If the side effects of ACE inhibitors become troublesome, angiotensin-2 receptor antagonists may be recommended. They work in a similar way to ACE inhibitors.
Calcium channel blockers
Calcium channel blockers work by relaxing the muscles of your artery walls, which causes your arteries to widen and lowers your blood pressure.
Calcium channel blockers are not recommended for people with a history of heart disease, liver disease or circulation problems.
Side effects include a flushed face, headaches, swollen ankles and dizziness.
You should not drink grapefruit juice if you are taking calcium channel blockers because this can cause your blood pressure to fall.
Thiazide diuretics work by reducing the amount of water in your blood and widening the walls of your arteries.
They are not recommended for pregnant women or people with gout (a type of arthritis where crystals develop inside the joints).
Thiazide diuretics have been known to reduce the level of potassium in your blood, which can interfere with your heart and kidney functions. They can also raise the level of sugar in your blood, which could lead to diabetes.
You will probably be advised to have blood and urine tests every six months so that your potassium and blood sugar levels can be monitored.
A few men reported they could not get or maintain an erection while taking thiazide diuretics, although this side effect resolved once the medication was withdrawn.
Read more about treatment of high blood pressure.
High cholesterol levels
Statins are a type of medication used to lower blood cholesterol levels. Statins block the effects of an enzyme in your liver called HMG-CoA reductase, which is used to make cholesterol.
Occasionally, statins can also cause muscle pain, weakness and tenderness. You should contact your GP if you experience these symptoms because your dosage may need to be adjusted.
If you have high blood cholesterol, you may need to take statins indefinitely.
Read more about the treatment of high cholesterol.
Preventing blood clots
As many of the serious complications that arise from atherosclerosis are associated with blood clots, such as heart attack and stroke, you may be given medication to help reduce the risk of a blood clot developing.
Medications used to prevent blood clots developing are known as antiplatelets. Platelets are tiny particles in the blood that help it to clot. Antiplatelets work by reducing the “stickiness” of platelets.
You may be advised to take low-dose aspirin, which, as well as being a painkiller, has blood-thinning properties.
If testing shows you have a higher than average risk of developing a blood clot, you may be given an additional antiplatelet medication called clopidogrel. Clopidogrel can also be used if you are allergic to aspirin.
Surgery may be required if certain important blood vessels become narrowed. These are the:
- coronary arteries, which supply blood to your heart (narrowing of your coronary arteries can trigger a heart attack)
- carotid arteries, which supply blood to your brain (narrowing of your carotid arteries can trigger a stroke)
Coronary angioplasty is a type of surgery used to widen your coronary arteries.
A long, flexible plastic tube called a catheter is inserted into a blood vessel and a balloon attached to the catheter is inflated to widen the artery.
A small metal tube called a stent is often used to help keep the artery open.
Coronary artery bypass graft
A coronary artery bypass graft (CABG) can be used to treat narrowing of the coronary arteries. During a CABG, healthy blood vessel segments (grafts) are taken from other parts of the body to bypass the blocked artery.
Segments of vein taken from your legs, arms and chest are used to create a new channel through which blood can be directed around the blocked part of the artery. This enables more blood to get through to the heart muscle.
Surgery is usually only recommended to widen the carotid arteries if you have experienced previous symptoms related to a blocked blood supply, such as a stroke or transient ischaemic attack (TIA).
Unlike the coronary arteries, preventative surgery on the carotid arteries is not usually recommended, except in cases where testing shows high levels of narrowing.
This is because studies have found that the benefits achieved in reducing the risk of a stroke in most people without any symptoms are outweighed by the risks associated with surgery.
A carotid endarterectomy is the most commonly used method of widening the carotid artery (the main artery in your neck).
During the procedure, a cut is made into the narrowed part of the artery and the inner lining of the artery is removed, along with any plaque inside it.
Most surgeons sew a patch into the opening to widen this section of the artery. The patch may be taken from a vein in your thigh or it might be synthetic (man-made).
Using a patch can reduce your risk of having a stroke after the operation, as well as reducing the likelihood of restenosis (the artery becoming narrowed again).
Carotid angioplasty uses a balloon catheter (a thin plastic tube with an inflatable balloon at one end), which is inserted into your femoral artery (the body’s main blood vessel) in your groin.
Under the guidance of X-ray, the catheter is threaded up into your femoral artery until it reaches your carotid artery.
The balloon is then inflated to around 5mm in diameter. This expands the artery, clearing the narrowing so blood is able to flow through it again.
Carotid angioplasty is a less invasive type of surgery than carotid endarterectomy, so you will experience less postoperative pain and have a faster recovery time.
However, research carried out in 2009 found people who had a carotid angioplasty were more likely to have re-narrowing of the carotid artery compared with those who had a carotid endarterectomy.
You should discuss the advantages and disadvantages of both types of surgery with your surgeon.
Extracranial to intracranial bypass
A new type of surgery used to treat blockage of the carotid artery is known as an extracranial to intracranial bypass.
In this type of surgery, a section of blood vessel found outside the skull is diverted and used to bypass the site of the blockage so that the blood supply to the brain can be restored.
Extracranial to intracranial bypass is still an evolving field of treatment and it is unclear how effective or safe it may be in the long term.
If you are offered extracranial to intracranial bypass surgery, it may be in the context of a clinical trial.
Making lifestyle changes is a very effective way of preventing or reversing the process of atherosclerosis.
There are five ways you can help reduce your risk of developing further coronary heart disease:
- eat a healthy diet
- stop smoking (if you smoke)
- take regular exercise
- lose weight (if you are overweight or obese)
- moderate your consumption of alcohol
These lifestyle changes are discussed in more detail below.
Eating an unhealthy diet high in fat will make your atherosclerosis worse and increase your risk of developing a heart attack or stroke.
There are two types of fat – saturated and unsaturated. Avoid foods that contain saturated fats because they will increase the levels of bad cholesterol in your blood.
Foods high in saturated fat include:
- meat pies
- sausages and fatty cuts of meat
- ghee (a type of butter often used in Indian cooking)
- hard cheese
- cakes and biscuits
- food that contains coconut or palm oil
Eating a small amount of unsaturated fat will increase the level of good cholesterol and help reduce any blockage in your arteries.
Foods high in unsaturated fat include:
- oily fish
- nuts and seeds
- sunflower, rapeseed and olive oil
Plant sterols and stanols are naturally occurring substances found in some types of food and are known to lower low-density lipoprotein (LDL, or “bad cholesterol”).
Sources of sterols and stanols include:
- legumes (such as beans or peas)
- olive oil
- vegetable oil
Research suggests that eating 2,000mg of sterols and stanols a day reduces levels of LDL cholesterol by around 10%, which in turn should reduce the risk of heart disease by around 25%.
The average intake of plant sterols and stanols is about 100-450mg.
There are now a number of commercial products promoted for their alleged “cholesterol-lowering” effects, which contain higher levels of sterols and stanols. These include special types of yoghurt, milk, margarine and cheese.
The National Institute for Health and Care Excellence (NICE) has stated that there may be a role for these types of products in the treatment of high cholesterol and atherosclerosis.
However, there is not currently enough evidence to confirm whether plant sterols and stanols are an effective method of preventing cardiovascular disease (CVD).
Smoking is a major risk factor for both heart attacks and strokes because it causes atherosclerosis and raises your blood pressure.
If you decide to stop smoking, your GP will be able to refer you to an NHS Stop Smoking Service, which will offer dedicated help and advice about the best ways to quit.
You can also call the Smokefree on 0300 123 1044 (7am to 11pm). The specially trained helpline staff offer free expert advice and encouragement.
If you are committed to giving up smoking but do not want to be referred to a stop smoking service, your GP should be able to prescribe treatment to ease your withdrawal symptoms.
High blood pressure
Persistent high blood pressure can put both your arteries and heart under extra strain, increasing your risk of having a heart attack or stroke.
High blood pressure can often be reduced by eating a healthy diet, moderating your consumption of alcohol, maintaining a healthy weight and taking regular exercise.
The dietary advice above also applies if you have high blood pressure. In addition, you should cut the amount of salt in your food and eat plenty of fruit and vegetables.
Salt raises your blood pressure. The more salt you eat, the higher your blood pressure. You should aim to eat less than 6g (0.2oz) of salt a day, which is about a teaspoonful. Find out more about how to cut down on salt.
Eating a low-fat diet that includes lots of fibre, such as wholegrain rice, bread and pasta, and plenty of fruit and vegetables has been proven to help lower blood pressure.
Fruit and vegetables are full of vitamins, minerals and fibre, and help keep your body in good condition. You should aim to eat five 80g portions of fruit and vegetables every day. Find out more about getting your 5 A DAY.
Regularly drinking alcohol above the limits recommended by the NHS will raise your blood pressure. Staying within the recommended levels is the best way to reduce your risk of developing high blood pressure.
The recommended limits for alcohol consumption are:
- three to four units a day for men
- two to three units a day for women
Alcohol is also high in calories, so you will gain weight if you drink regularly. Being overweight will also increase your blood pressure. Find out how many calories are in popular drinks.
Being overweight forces your heart to work harder to pump blood around your body, which can raise your blood pressure. Find out if you need to lose weight with the BMI healthy weight calculator.
If you do need to shed some weight, it is worth remembering that just losing a few pounds will make a big difference to your blood pressure and overall health. Get tips on losing weight safely.
Being active and taking regular exercise will lower your blood pressure by keeping your heart and blood vessels in good condition. Regular exercise will help you lose weight, which will also help lower your blood pressure.
If you have a history of cardiovascular disease, low-impact activities such as walking, swimming and cycling are recommended. More strenuous activities such as playing football and squash may not be advised. Check with your GP for more information.
Read more about preventing high blood pressure.