Peripheral arterial disease

Peripheral arterial disease (PAD) is a common condition in which a build-up of fatty deposits in the arteries restricts blood supply to leg muscles.

Introduction

Peripheral arterial disease (PAD) is a common condition in which a build-up of fatty deposits in the arteries restricts blood supply to leg muscles. It is also known as peripheral vascular disease (PVD).

Although many people with PAD have no symptoms, some people have painful aching in their legs brought on by walking. These aches will usually disappear after a few minutes of resting.

Read more about symptoms of peripheral arterial disease.

If you experience recurring leg pain with exercise, see your doctor. PAD is usually diagnosed through a physical examination by your doctor.

They will also measure the blood pressure in your leg, using the ankle brachial pressure index (ABPI). This involves comparing blood pressure readings from your arm and your ankle. A difference between these readings may indicate PAD.

Read more about diagnosing peripheral arterial disease.

Why does it happen?

Peripheral arterial disease is a cardiovascular disease, meaning it affects blood vessels. It is usually caused by a build-up of fatty deposits in the walls of the leg arteries. The fatty deposits, called atheroma, are made up of cholesterol and other waste substances.

The build-up of atheroma on the walls of the arteries makes the arteries narrower and restricts the flow of blood to the legs. This process is called atherosclerosis.

Read more about the causes of peripheral arterial disease.

Who is affected?

Rates of PAD are strongly associated with older age. It is estimated that it develops in:

  • 2.5% of people aged under 60
  • 8.3% of people aged 60–69
  • 19% of people aged over 70

Men are more likely to develop the symptoms of PAD earlier in life than women.

There are certain things that can increase your chances of developing PAD and other cardiovascular diseases, including:

Treating and preventing peripheral arterial disease

PAD is largely treated through medication and lifestyle changes.

Completely stopping smoking and getting regular exercise are the main lifestyle changes that can ease the symptoms of PAD and reduce the chances of the condition worsening.

The underlying causes should also be treated, such as reducing high blood pressure and cholesterol, and treating diabetes. Medication can be used to improve blood flow. In some cases, surgery may be needed to treat PAD.

Read more about treatments for peripheral arterial disease and preventing peripheral arterial disease.

Complications of peripheral arterial disease

While PAD is not immediately life-threatening, the process of atherosclerosis that causes it can lead to serious problems.

Having PAD means you have a much higher risk of developing other serious cardiovascular diseases, such as:

Also, if the symptoms of PAD worsen, there is a risk that tissue of the lower leg will begin to die (this is known as gangrene), which in severe cases requires the lower leg to be amputated.

Read more about the complications of peripheral arterial disease.

If treatment is successful, and lifestyle changes are maintained, your situation will usually improve.

However, if you are unable or unwilling to make lifestyle changes, especially if your leg pain is getting worse, it is estimated there is a:

  • one-in-five chance you will experience a non-fatal heart attack or stroke
  • 5% chance that one or both of your legs will need to be amputated
  • one-in-three chance you will die prematurely

Symptoms

Many people with peripheral arterial disease (PAD) do not have any symptoms. However, you may feel painful aching in your leg muscles triggered by physical activity such as walking or climbing stairs.

The pain usually develops in your calves, but sometimes your hip, buttock or thigh muscles can be affected. The pain can range from mild to severe.

The pain will usually go away after 5–10 minutes when you rest your legs. Other symptoms of PAD may include:

  • hair loss on your legs and feet
  • numbness or weakness in the legs
  • brittle, slow-growing toenails
  • ulcers (open sores) on your feet and legs, which do not heal
  • changing skin colour on your legs, turning pale or bluish
  • shiny skin
  • the muscles in your legs may shrink
  • men may develop impotence (erectile dysfunction)

When to seek medical advice

If you experience recurring episodes of leg pain, make an appointment with your doctor, especially if you are a smoker or have a confirmed diagnosis of diabetes, high blood pressure and/or high cholesterol.

Many people mistakenly think recurring episodes of leg pain are part of growing older. This is not the case. There is no reason why an otherwise healthy person should experience leg pain.

When to seek urgent medical advice

Some symptoms may suggest the supply of blood to your legs has become severely restricted and you may need to see a doctor urgently. These include:

  • being unable to move muscles in the affected leg
  • a sudden loss of normal sensation in the affected leg
  • feeling a burning or prickling sensation in the affected leg
  • your toes or leg suddenly turns white or blue
  • the skin on your toes or lower limbs becomes cold and numb, and turns reddish and then black or begins to swell and produce foul-smelling pus, causing severe pain

If you experience any of the symptoms listed above, contact your doctor as soon as possible. If this is not possible, phone your local out-of-hours service.

Causes

Peripheral arterial disease (PAD) is usually caused by a build-up of fatty deposits on the walls of the arteries inside the legs. The fatty deposits, called atheroma, are made up of cholesterol and other waste substances.

The build-up of atheroma on the walls of the arteries makes the arteries narrower and restricts the flow of blood to the legs. This process is called atherosclerosis.

People with PAD can experience painful aching in their leg muscles during physical activity because the muscles are not receiving the blood supply they need.

Like all tissue in your body, muscles in your legs need a constant supply of blood to function properly. When you are using your leg muscles, the demand for blood increases four-fold. However, if the arteries in your legs are blocked, the supply of available blood cannot meet the demand.

This shortfall between supply and demand causes your muscles to experience painful aches which usually get better when you rest your legs.

Increased risk of PAD

There are some things that cannot be changed which may increase your chances of developing PAD, such as a family history of heart disease and atherosclerosis, or your age.

As you get older, your arteries naturally begin to harden and get narrower, which can lead to atherosclerosis and then PAD.

However, there are many things that can dangerously speed up this process. These are described below.

Smoking

Smoking is the single most important thing that increases your risk of PAD. Smoking can damage the walls of your arteries. Tiny blood cells, known as platelets, will then form at the site of the damage to try to repair it. This can cause your arteries to narrow.

It is estimated that smokers are six times more likely to develop PAD than non-smokers and more than 80% of people who develop PAD are current or former smokers.

Diabetes

If you have poorly controlled type 1 or type 2diabetes, the excess glucose in your blood can damage your arteries.

People with diabetes are two to four times more likely to develop PAD, and having a combination of poorly controlled diabetes and PAD is a major risk factor for amputation. People with diabetes and PAD are 15 times more likely to need an amputation than people with PAD who do not have diabetes.

High cholesterol

Cholesterol is a type of fat essential for the body to function.

There are two main types of cholesterol:

  • Low-density lipoprotein (LDL) is the main cholesterol transporter and carries cholesterol from your liver to cells that need it. If there is too much cholesterol for the cells to use, this can cause a harmful build-up in your blood and lead to atherosclerosis. For this reason, LDL cholesterol is known as "bad cholesterol", and lower levels are better.
  • High-density lipoprotein (HDL) carries cholesterol away from the cells and back to the liver, where it is either broken down or passed from the body as a waste product. For this reason, it is referred to as "good cholesterol", and higher levels are better.

Most of the cholesterol your body needs is made by your liver. However, if you eat foods high in saturated fat, the fat is broken down into LDL ("bad cholesterol").

Read more about high cholesterol.

High blood pressure

Your arteries are designed to pump blood at a certain pressure, and if blood pressure is too high (known as hypertension), the walls of the arteries can become damaged. High blood pressure can be caused by:

  • being overweight
  • drinking excessive amounts of alcohol
  • stress
  • smoking
  • a lack of exercise

Homocysteine

Homocysteine is a type of amino acid (the molecules that make up protein) found in the blood. Research has found 30–40% of people with PAD have higher-than-average levels of homocysteine in their blood, and one-in-four people who develop leg pain have extremely high levels.

It has been suggested that high levels of homocysteine may damage the walls of the arteries, leading to atherosclerosis, but this has not been proven.

Vitamin B supplements and eating foods high in folic acid, such as green leafy vegetables or wholegrains, are known to lower homocysteine levels. However, researchers found no significant reduction in risk of cardiovascular disease when people with PAD increased the amount of vitamin B and folic acid in their diet.

Diagnosis

If your doctor suspects a diagnosis of peripheral arterial disease (PAD), they will carry out a physical examination of your leg.

PAD can cause a number of noticeable signs and symptoms, such as:

  • shiny skin
  • brittle toenails
  • hair loss on your legs and feet
  • the pulse in your leg being very weak or undetectable
  • leg ulcers

Your doctor may also ask about your symptoms and your personal and family medical histories.

The ankle brachial pressure index

The ankle brachial pressure index (ABPI) test is widely used to diagnose PAD, as well as assessing how well you are responding to treatment.

While you rest on your back, your doctor or practice nurse will measure the blood pressure in your upper arm and your ankle. These measurements are taken with a Doppler probe, which uses sound waves to determine the flow of blood in your arteries.

They then divide the second result (from your ankle) by the first result (from your arm).

If your circulation is healthy, the blood pressure in both parts of your body should be exactly or almost the same and the result of your ABPI would be one.

However, if you have PAD, the blood pressure in your ankle will be lower due to a reduction in blood supply, so the results of the ABPI would be less than one.

In some cases, ABPI may be carried out after getting you to run on a treadmill or cycle on an exercise bike. This is a good way of seeing the effect of physical activity on your circulation.

Further testing

In most cases, your doctor will be able to confirm a diagnosis of PAD by doing a physical examination, asking about your symptoms and checking your ABPI score.

Further testing is usually only required if:

  • There is uncertainly about the diagnosis – for example, if you have symptoms of leg pain but your ABPI score is normal.
  • You do not fit the expected profile of somebody with PAD; for example, you are under 40 and have never smoked.
  • The restriction of blood supply in your leg is severe enough that treatment may be required.

Additional hospital-based tests that can be used include:

In some cases, the contrast agent may be injected directly into the arteries of your leg and X-rays may be used to produce the images.

Treatment

There are two main types of treatment used in the management of peripheral arterial disease (PAD).

These are:

  • making lifestyle changes to improve symptoms and reduce your risk of developing a more serious cardiovascular disease (CVD), such as coronary heart disease
  • taking medication to address the underlying cause of your PAD and reduce the risk of developing another CVD. For example, a statin can be used to lower your cholesterol levels

Surgery may be used in some cases. For example, if you experience pain in your leg while resting or if there is tissue loss. These treatment types are discussed in more depth below.

Lifestyle changes

The two most important lifestyle changes you can make if you are diagnosed with PAD are:

  • if you currently smoke, you should stop
  • take regular exercise

Smoking

Quitting smoking will reduce your risk of PAD getting worse and another serious cardiovascular disease developing.

Research has found people who continue to smoke after receiving their diagnosis are five times more likely to have a heart attack and seven times more likely to die from a complication of heart disease than people who quit after receiving their diagnosis.

People who stop smoking usually notice an improvement in their symptoms and an improvement in their ankle brachial pressure index (ABPI) score.

Exercise

Evidence suggests regular exercise helps reduce the severity and frequency of PAD symptoms, while at the same time reducing the risk of developing another CVD.

Research has found that after six months of regular exercise, a person can:

  • walk for two to three times longer before experiencing pain
  • walk a lot further before experiencing pain
  • see a 20% improvement in their ABPI score

If you are diagnosed with PAD, it is likely you have not taken part in regular exercise for many years (although this is not true for everyone, such as previously fit people with type 1 diabetes).

The National Institute for Health and Care Excellence (NICE) recommends supervised exercise as one of the first steps for managing PAD. This may involve group exercise sessions with other people with CVD, led by a trainer.

The exercise programme usually involves two hours of supervised exercise a week for three months. But ideally, over time, you should be aiming to exercise daily for the rest of your life, as the benefits of exercise are quickly lost if it is not frequent and regular.

The preferred exercise is walking. It is normally recommended you walk as far and as long as you can before the symptoms of pain become intolerable. Once this happens, rest until the pain goes and begin walking again until the pain returns. Keep using this "stop-start" method until you have spent at least 30 minutes walking.

You will probably find the exercise course challenging, as the frequent episodes of pain can be upsetting and off-putting. However, if you persevere, you should gradually notice a marked improvement in your symptoms and you will begin to go longer and longer without experiencing pain.

Medication

Different medications can be used to treat the underlying causes of PAD while reducing your risk of developing another CVD.

Some people may only need to take one or two of the medications discussed below, while others may need all of them.

Statins

If blood tests show that your levels of LDL cholesterol ("bad cholesterol") are high, you will be prescribed a type of medication called a statin.

Statins work by helping to reduce the production of LDL cholesterol by your liver.

Common side effects of statins include:

  • digestive disorders, such as constipation and diarrhoea
  • insomnia
  • pain in the muscles and joints
  • nausea (feeling sick)

Antihypertensives

Antihypertensives are a group of medications used to treat high blood pressure (hypertension).

It is likely you will be prescribed an antihypertensive drug if your blood pressure is higher than 140/90mmHg if you do not have diabetes, or 130/80mmHg if you do have diabetes.

Read more about diagnosing high blood pressure.

A widely used type of antihypertensive is an angiotensin-converting enzyme (ACE) inhibitor.

ACE inhibitors block the actions of some hormones that help regulate blood pressure. They help to reduce the amount of water in your blood and widen your arteries, both of which will decrease your blood pressure.

Side effects of ACE inhibitors include:

  • dizziness
  • tiredness or weakness
  • headaches
  • a persistent dry cough

Most of these side effects pass in a few days, although some people find they have a dry cough a bit longer.

If side effects become particularly troublesome, a medication that works in a similar way to ACE inhibitors, known as an angiotensin-2 receptor antagonist, may be recommended.

ACE inhibitors can cause unpredictable effects if taken with other medications, including some over-the-counter ones, so check with your doctor or pharmacist before taking anything in combination with this medication.

Read more about treating high blood pressure

Antiplatelets

One of the biggest potential dangers if you have atherosclerosis is a piece of fatty deposit (plaque) breaking off from your artery wall. This can cause a blood clot to develop at the site of the broken plaque.

If a blood clot develops inside an artery that supplies the heart with blood (a coronary artery) it can trigger a heart attack. Similarly, if a blood clot develops inside any of the blood vessels going to the brain, it can trigger a stroke.

You will probably be prescribed an antiplatelet medication to reduce your risk of blood clots. This medication reduces the ability of platelets (tiny blood cells) to stick together, so if a plaque does break apart, you have a lower chance of a blood clot developing.

Low-dose aspirin (around 75mg a day) is usually recommended.

Common side effects of aspirin include:

  • irritation of the stomach or bowel
  • indigestion
  • nausea (feeling sick)

If you are unable to take aspirin (for example, if you have a history of stomach ulcers or you are allergic to aspirin), an alternative antiplatelet called clopidogrel can be used.

Side effects of clopidogrel include:

  • diarrhoea
  • pains in your stomach and bowel
  • nosebleeds
  • bruising
  • blood in your urine
  • blood in your stools

Naftidrofuryl oxalate

NICE recommends naftidrofuryl oxalate for the treatment of intermittent claudication if you have PAD.

Naftidrofuryl oxalate improves blood flow in the body, and is often used if you prefer not to have surgery or your supervised exercise programme has not led to a satisfactory improvement in your condition.

Side effects of naftidrofuryl oxalate include:

  • dizziness
  • headache
  • stomach pains
  • diarrhoea
  • rashes

Surgery

There are two main types of surgical treatment for PAD:

  • angioplasty – where a blocked or narrowed section of artery is widened by inflating a tiny balloon inside the vessel
  • bypass graft – where blood vessels are taken from another part of your body and used to bypass the blockage in an artery

Angioplasty vs bypass surgery

Both types of surgery have their own set of pros and cons.

An angioplasty is less invasive (it does not involve making major incisions in your body). It is usually performed under a local anaesthetic as a day procedure. This means you will be able to go home the same day you have the operation. You also feel less pain after an angioplasty. However, the improvement in symptoms varies from person to person and may only last for around 6-12 months.

Bypass surgery, which is usually only used when angioplasty is not suitable or has failed, has a longer recovery time (around two to three weeks). However, the improvement in symptoms usually lasts for longer than a year.

However, after two years, both techniques have broadly the same success rate of improving symptoms.

Both techniques carry a risk of causing serious complications such as a heart attack, stroke and even death. One study found that the risk of death for angioplasty was around one person in every 200, and the risk for bypass graft was slightly higher – around two to three people in every 100.

Before recommending treatment, a team of specialist surgeons, doctors and nurses will discuss the options with you – including the potential risks and benefits.

Surgery is not always successful in treating PAD and is usually only recommended under the following circumstances:

  • Your leg pain is so severe it prevents you from carrying out everyday activities.
  • Your symptoms have failed to respond to treatments discussed above.
  • The results of tests, such as ultrasound scans, show surgery is likely to improve symptoms.

Both techniques are discussed in more detail below.

Angioplasty

A tiny hollow tube known as a catheter is inserted into one of the arteries in your groin. The catheter is then guided to the site of the blockage.

On the tip of the catheter is a balloon which is inflated when the catheter is in place. This helps widen the blood vessel. Sometimes a metal mesh 'tube' known as a stent may be left in place to help keep the artery open.

Read more about angioplasty.

Bypass graft

If angioplasty is unsuccessful or unsuitable, a bypass graft may be performed. During surgery a length of healthy vein in your leg is removed. The vein is then joined (grafted) above and below the blocked vein so the blood supply can be rerouted, or bypassed, through the healthy vein. Sometimes a section of artificial tubing can be used as an alternative to a grafted vein.

For details on a similar operation, read more about a coronary artery bypass graft.

Complications

The build up of fat in the arteries (atherosclerosis) that causes peripheral arterial disease (PAD) can also lead to other serious conditions.

Critical limb ischemia

Critical limb ischemia (CLI) occurs when blood flow to the limbs is severely restricted from atherosclerosis.

Symptoms of CLI include:

  • A severe burning pain in your legs and feet even when you are resting; the pain often occurs at night and episodes of pain can last several hours. You may find you have to hang your legs out of bed to get relief.
  • Your skin turns pale, shiny, smooth and dry.
  • You may develop wounds and ulcers (open sores) on your feet and legs that show no sign of healing.
  • The muscles in your legs begin to waste away.
  • The skin on your toes or lower limbs becomes cold and numb and turns reddish and then black or begins to swell and produce foul-smelling pus, causing severe pain.

If you think you are developing the symptoms of CLI, contact your doctor immediately. If this is not possible, telephone your local out-of-hours service.

CLI is treated using an angioplasty or bypass graft (read about treating peripheral arterial disease for more information on these operations). However, these may not always be successful and you may be advised to have an amputation below the knee. Around one-third of people with CLI will require an amputation.

CLI is an extremely serious complication that can be challenging to treat. Around one in four people will die from a complication of CLI, such as infection.

Heart attack and stroke

The build up of fat in the arteries in the legs that causes PAD can also affect other areas of your body, such as the arteries supplying the heart and brain.

Blockages in these arteries can cause a heart attack or a stroke.

Prevention

The most effective way to prevent peripheral arterial disease (PAD) or stop your symptoms of PAD worsening is to tackle the build up of fat in your arteries (atherosclerosis).

There are five main ways you can achieve this:

  • stop smoking
  • eat a healthy diet
  • 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.

Smoking

If you smoke, it is strongly recommended you quit as soon as possible. Your doctor may recommend and prescribe medication that can help you give up.

It is recommended you use an anti-smoking treatment such as nicotine replacement therapy (NRT) or bupropion (a medication used to reduce cravings for cigarettes). People who use these treatments have a much greater success rate in permanently quitting than people who try to quit using willpower alone.

Diet

It is recommended you eat two to four portions of oily fish a week. Oily fish contains a type of fatty acid called omega-3, which can help lower your cholesterol levels.

Good sources of omega-3 include:

  • herrings
  • sardines
  • mackerel
  • salmon
  • trout
  • tuna

If you are unable or unwilling to eat oily fish, your doctor may recommend you take an omega-3 food supplement. However, never take a food supplement without first consulting your doctor. Some supplements, such as beta-carotene, can be harmful.

It is also recommended you eat a Mediterranean-style diet. This means you should eat more bread, fruit, vegetables and fish and less meat. Replace butter and cheese with products that are vegetable and plant-oil based, such as olive oil.

Weight management

If you are overweight or obese, aim to lose weight and maintain a healthy weight by using a combination of regular exercise and a calorie-controlled diet.

Alcohol

If you drink alcohol, do not exceed recommended daily limits (three to four units a day for men and two to three units a day for women).

A unit of alcohol is roughly half a pint of normal-strength lager, a small glass of wine or a single measure (25ml) of spirits. Regularly exceeding recommended alcohol limits will raise your blood pressure and cholesterol level, which will increase the risk of your PAD symptoms worsening and increase your risk of developing another more serious type of cardiovascular disease.

Contact your doctor if you find it difficult to moderate your drinking. Counselling services and medication can help

Regular exercise

If you do not have PAD, then a minimum of 150 minutes of vigorous exercise a week is recommended. The exercise should be strenuous enough to leave your heart beating faster, and you should feel slightly out of breath afterwards.

Activities you could incorporate into your exercise programme include:

  • brisk walking
  • hill climbing
  • running
  • cycling
  • swimming

If you find it difficult to achieve 150 minutes of exercise a week, start at a level you feel comfortable with. For example, you could do 5–10 minutes of light exercise a day and then gradually increase the duration and intensity of your activity as your fitness begins to improve.

For guidance on exercise in people with PAD, read more about treating peripheral arterial disease.

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