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Peripheral arterial disease

 

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

The most common symptom of PAD is painful cramping in the legs brought on by walking. Cramps then disappear after 5-10 minutes of resting.

However, it is estimated that up to two-thirds of people with PAD have no noticeable symptoms. See Peripheral arterial disease - Symptomsfor more information.

PAD, atherosclerosis and cardiovascular disease

PAD is a cardiovascular disease, meaning that it affects the blood vessels.

While it is not immediately life-threatening, the fact the PAD has developed (even if it does not cause any noticeable symptoms) suggests that you have a high degree of atherosclerosis.This is a potentially serious and progressive (gets worse over time) condition where the body's medium and large arteries become clogged up by fatty substances, such as cholesterol.

Having a high degree of atherosclerosis means you have a much higher risk of developing another, more serious cardiovascular disease, such as:

Receiving a diagnosis of PAD should therefore be taken as a serious warning sign that you need to make significant lifestyle changes (see below) to reduce your risk of disability and possibly death.

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

How common is PAD?

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

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

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

Risk factors for PAD are the same as for other cardiovascular diseases and include:

PAD is treated through medication and making certain lifestyle changes. The two most important lifestyle changes are to quit smoking if you are a smoker and to exercise daily. See Peripheral arterial disease - Treatment for more information.

Surgery may be used in the more serious cases of PAD.

Outlook

The outlook for PAD depends to a large extent on whether you are willing to make, and then stick to, the recommended lifestyle changes. If you are, the outlook is moderate to good.

The outlook is less favourable if you are unable or unwilling to make lifestyle changes, especially if you are experiencing worsening symptoms of leg pain. In these circumstances, within five years of the start of symptoms, it is estimated there is a:

  • one-in-four chance that symptoms will have worsened
  • one-in-five chance that 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 that you will die

The most common symptom of peripheral arterial disease (PAD) is painful cramping in your leg muscles triggered by physical activity such as walking or climbing the stairs.

The pain usually develops in your calves, but sometimes your hips or thigh muscles can be affected. It can feel mild to severe.

The pain will usually go away after 5-10 minutes when you rest your legs. This pattern of symptoms is known as "intermittent claudication" (claudication is a Latin term that loosely translates as "limping").

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
  • you are unable to feel a pulse in your leg or the pulse feels much weaker than normal
  • men may develop impotence (erectile dysfunction)

When to seek medical advice

Many people mistakenly think that 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.

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

When to seek urgent medical advice

Some symptoms may suggest that 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 the muscles in the affected leg
  • feeling a burning or prickling sensation in the affected leg
  • your toes suddenly turn 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 GP as soon as possible.

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 cramps in their leg muscles during physical activity because the muscles are not receiving the blood supply that they need.

Like all tissue in your body, the muscles in your legs need a constant supply of blood to function properly. When you are making use of your leg muscles, the demand for blood increases ten-fold. But 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 cramps, which only get better after you rest your legs.

Risk factors for PAD

Over time 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 factors that can dangerously speed up this process. These are described below.

Smoking

The single most important risk factor for PAD is smoking. 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 2 diabetes, 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-fat diets and cholesterol

Cholesterol is a type of fat that is essential for the body to function. Cholesterol helps to produce hormones, to make up cell membranes (the walls that protect individual cells) and to protect nerve endings.

Cholesterol cannot travel around the body on its own because it does not dissolve in water. Instead, it is carried in your blood by molecules called lipoproteins.

The two main lipoproteins are LDL and HDL:

  • Low-density lipoprotein (LDL) is the main cholesterol transporter and carries cholesterol from your liver to the 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 that your body needs is made by your liver. However, if you eat foods that are high in saturated fat, the fat is broken down into LDL ("bad cholesterol").

Foods that are high in saturated fat include:

  • biscuits
  • cakes
  • bacon
  • sausages
  • processed meat
  • butter
  • cream

Blood cholesterol is measured in units called millimoles per litre of blood, often shortened to mmol/L. It is estimated that the risk of developing PAD increases by 10% for each 0.25 mmol/L rise in your cholesterol levels.

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

See the Health A-Z topic about High blood pressure for more information and advice.

Homocysteine

Homocysteine is a type of amino acid (molecule that makes up protein) found in the blood. Research has found that 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.

If your GP suspects a diagnosis of peripheral arterial disease (PAD), they will usually first 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
  • the pulse in your leg being very weak or undetectable

The ankle brachial pressure index

The ankle brachial pressure index (ABPI) is a widely used test in the diagnosis of PAD, as well as a useful way of assessing how well you are responding to treatment.

First, your GP measures the systolic blood pressure in your upper arm (the blood pressure when your heart beats and forces blood around your body). Then take a similar measurement in your ankle.

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 1.

But 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 1.

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.

In general terms, an ABPI score of:

  • less than 0.95 would be considered abnormal
  • 0.9-0.5 is often seen in people who experience leg pain when exercising
  • 0.5-0.2 is associated with persistent leg pain
  • less than 0.5 would suggest that the blood supply is severely restricted and they are at risk of losing the leg
  • less than 0.2 would normally mean that the tissues in the feet have begun to die (gangrene) and amputation may be required

Further testing

In most cases, your GP 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 surgery may be required (this would usually be if your ABPI score was less than 0.5).

Additional tests that can be used include:

 

  • ultrasound scan- where sound waves are used to build up a picture of the arteries in your leg. This can identify exactly where in your arteries there are blockages or narrowing.
  • angiogram - a special dye known as a contrast agent is injected into your leg. The agent shows up clearly on a computerised tomography (CT) or magnetic resonance imaging (MRI) scan.

CT scan uses X-rays and a computer to create detailed images of the inside of your body.

An MRI scan uses strong magnetic fields and radio waves to produce a detailed image of the inside of the body.

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

  • 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 PAD and reduce your risk of developing another CVD. For example, a statin can be used to lower your cholesterol levels.

Surgery may be used as a last resort. 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, stop. 
  • Take regular exercise.

Smoking

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

Research has found that 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 quit smoking usually notice an improvement in their symptoms and an improvement in their ankle brachial pressure index (ABPI) score.

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

If you decide to stop smoking, your GP will be able to refer you to a local smoking cessation service which will provide you with dedicated help and advice about the best ways for you to give up smoking. You can also call the National Smokers Quitline at 1850201203, or log on to www.quit.ie, or join our facebook page at www.facebook.com/hsequit for further support.

Exercise

There is a lot of high-quality evidence showing that taking part in regular exercise helps to 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).

So it is usually recommended that you are referred for a course of group exercise sessions with other people with CVD, under the supervision of a trainer.

Each session should last at least 30-45 minutes and be performed at least three times a week for a minimum of 12 weeks. But ideally, over time, you should be aiming to exercise daily for the rest of your life.

The preferred exercise is walking. It is normally recommended that 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. But if you persevere, you should gradually notice a marked improvement in your symptoms and you will begin to go longer and longer without experiencing any 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 to take 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, diarrhoea, dyspepsia (acid in the stomach) and flatulence (passing wind)
  • headache
  • insomnia (difficulty sleeping)
  • myalgia (pain in the muscles)
  • arthralgia (pain in the joints)
  • nausea (feeling sick)

For more information, see the Health A-Z topic on Statins.

Antihypertensives

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

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. See High blood pressure - Diagnosis for more information on how blood pressure is measured.

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

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

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 GP or pharmacist before taking anything in combination with this medication.

For more information, see the Health A-Z topic on

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 (usually 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
  • indigestion (dyspepsia)
  • pains in your stomach and bowel
  • nosebleeds
  • bruising
  • blood in your urine
  • blood in your stools

For more information, see the Health A-Z topics on Low-dose aspirin and Clopidogrel.

Cilostazol

If your symptoms of leg pain are severely disrupting your normal daily activities, you may be prescribed a medication called cilostazol.

Cilostazol reduces the ability of the blood to clot, while causing the arteries in the legs to expand, which should both help improve the blood supply to your legs.

However, cilostazol can potentially cause a wide range of side effects, which is why it is only used to treat the most problematic cases of PAD (although it would be unusual to experience any more than a few of these).

Common side effects of cilostazol include:

  • headache
  • diarrhoea
  • nausea
  • vomiting
  • swelling of your feet, ankles or face
  • rapid heartbeat
  • sore throat
  • dizziness
  • chest pain
  • itchy skin rash
  • indigestion and flatulence (burping and passing wind)

If you do feel dizzy when taking cilostazol, you should not drive or operate complex or heavy machinery.

Cilostazol is not recommended if you are pregnant or breastfeeding, and you should avoid getting pregnant if you are on this medication.

If you suspect that you have become pregnant when taking cilostazol, contact your GP for advice as soon as possible.

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

Both types of surgery have their own set of pros and cons (see box).

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

  • Your leg pain is so severe that you are essentially disabled as you are no longer able to walk any significant distance.
  • Your symptoms have failed to respond to the treatments discussed above.
  • The results of tests, such as ultrasound scans, show that surgery is likely to improve symptoms.

Both techniques are discussed in more detail below.

Angioplasty

An angioplasty is carried out under a local anaesthetic,which means you will be awake during the operation but your legs will be numbed by the anaesthetic, so you will not feel any pain.

The surgeon will insert a tiny hollow tube known as a catheter 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. Once the catheter is in place, the balloon is inflated, which helps widen the vessel. Sometimes a hollow metal tube known as a stent may be left in place to help keep the artery open.

For more information on this procedure, see the Health A-Z topic on Angioplasty.

Bypass graft

A bypass graft is performed under a general anaesthetic, which means you will be asleep during surgery and you will not experience any pain.

During surgery the surgeon will remove a small section of a healthy vein in your leg. The vein is then grafted (joined) onto 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 more information on this procedure, see the Health A-Z topic on Coronary artery bypass graft.

Angioplasty vs bypass surgery

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

As angioplasty is non-invasive (it does not involve making major incisions in your body), it has a faster recovery time and you feel less pain after surgery. However, the improvement in symptoms tends to only last for around 6–12 months.

Bypass surgery has a longer recovery time (around two to three weeks), although 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 going ahead, discuss the risks and benefits associated with each technique with your surgical team.

Peripheral arterial disease and diabetes

Having poorly controlled diabetes increases your risk of PAD symptoms worsening and raises your chance of developing heart disease, stroke or a heart attack.

If you have PAD and poorly-controlled diabetes, your treatment may involve:

  • making lifestyle changes such as exercising more regularly and reducing the amount of sugar and fat in your diet
  • insulin injections, if you were not previously using them

High levels of glucose may also cause nerve damage, so you may damage your skin without realising it. Your reduced blood supply means that fewer infection-fighting white blood cells can reach the injury, so any damage to your skin is more vulnerable to infection. This is how a diabetic foot ulcer happens, which is a leading cause of gangrene and amputation in people with diabetes.

Check your feet daily for any problems such as breaks in the skin, pain or swelling and report any problems to your GP immediately.

Critical limb ischemia (CLI)

Critical limb ischemia (CLI) is a condition that 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.
  • Your skin turns pale, shiny, smooth and dry.
  • You have wounds and ulcers (open sores) in 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 become 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 GP immediately.

CLI is treated using an angioplasty or bypass graft (see Peripheral arterial disease - Treatment for more information). 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.

The most effective way to prevent peripheral arterial disease (PAD) or prevent your symptoms of PAD worsening is to prevent or reverse the process of atherosclerosis.

There are five main ways you can achieve this:

  • stop smoking (if you smoke)
  • 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 that you quit as soon as possible.

If you decide to stop smoking, your GP will be able to refer you to a local smoking cessation service which will provide you with dedicated help and advice about the best ways for you to give up smoking. You can also call the National Smokers Quitline at 1850201203, or log on to www.quit.ie, or join our facebook page at http://www.facebook.com/HSEquit for further support.

Diet

It is recommended that 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 GP may recommend that you take an omega-3 food supplement. However, never take a food supplement without first consulting your GP. Some supplements, such as beta-carotene, can be harmful.

It is also recommended that 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.

See the Health A-Z topic about Obesity - Treatment for more information and advice.

Alcohol

If you drink alcohol, do not exceed the recommended weekly limits (twenty one standard drinks a week for men and fourteen standard drinks a week for women).

A standard drink of alcohol is roughly half a pint of normal-strength beer, a small glass of wine or a pub measure of spirits. Regularly exceeding the recommended alcohol limits will raise your blood pressure and your 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 GP if you find it difficult to moderate your drinking. Counselling services and medication can help you to reduce your alcohol intake.

See Alcohol misuse - Treatment for more information.

Regular exercise

If do you not have PAD then a minimum of 30 minutes of vigorous exercise a day, five times a week, is the recommended amount of exercise. The exercise should be strenuous enough to leave your heart beating faster, and you should feel slightly out of breath afterwards.

Activities that you could incorporate into your exercise programme include:

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

If you find it difficult to achieve 30 minutes of exercise a day, start at a level that 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, see Peripheral arterial disease - Treatment.


Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.