A thick patch of atheroma makes the artery narrower. This reduces the flow of blood through the affected section of artery. Tissues 'downstream' have a reduced blood supply, which can lead to symptoms and problems.
Atheroma can develop in any artery, but the common arteries affected are:
- Arteries taking blood to the heart - this is called ischaemic heart disease and may lead to problems such as angina and heart attacks.
- Arteries taking blood to the brain - which may eventually lead to a stroke.
- Arteries taking blood to the legs - which may lead to PAD.
What causes atheroma?
Everybody has some risk of developing atheroma. However, certain 'risk factors' increase the risk. Risk factors include:
- Lifestyle risk factors that can be prevented or changed:
- Smoking.
- Lack of physical activity (a sedentary lifestyle).
- Obesity.
- An unhealthy diet.
- Excess alcohol.
- Treatable or partly treatable risk factors:
- Hypertension (high blood pressure).
- High cholesterol blood level.
- High triglyceride (fat) blood level.
- Diabetes.
- Kidney diseases causing diminished kidney function.
- Fixed risk factors - ones that you cannot alter:
- A strong family history. This means if you have a father or brother who developed heart disease or a stroke before they were 55, or in a mother or sister before they were 65.
- Being male.
- An early menopause in women.
- Age. The older you become, the more likely you are to develop atheroma.
- Ethnic group. For example, people who live in the UK with ancestry from India, Pakistan, Bangladesh, or Sri Lanka have an increased risk.
However, if you have a fixed risk factor, you may want to make extra effort to tackle any lifestyle risk factors that can be changed.
Note: Some risk factors are more 'risky' than others. For example, smoking causes a greater risk to health than obesity. Also, risk factors interact. So, if you have two or more risk factors, your health risk is much more increased than if you just have one. For example, a middle aged male smoker who does little physical activity and has a strong family history of heart disease has quite a high risk of developing a cardiovascular disease such as a heart attack, stroke, or peripheral arterial disease before the age of 60.
Research is looking at some other factors that may be risk factors. For example, high blood levels of apolipoprotein B or homocysteine are being investigated as possible risk factors.
What are the symptoms of peripheral arterial disease?
The typical symptom is pain which develops in one or both calves when you walk. This is called 'intermittent claudication'. It is due to narrowing of the femoral artery - the most common site for atheroma to develop in PAD. When you walk, the calf muscles need an extra blood and oxygen supply. The narrowed artery cannot deliver the extra blood, and so pain occurs from the oxygen-starved muscles. The pain soon goes when you slow down or stop. The pain comes on more rapidly when you walk up a hill or stairs than when you walk on the flat.
If an artery higher 'upstream' is narrowed, such as the iliac artery or aorta, then you may develop pain in your thighs or buttocks when you walk.
If the blood supply to the legs becomes worse, the following may be found by a doctor who examines you:
- Poor hair growth below your knee, and poor toenail growth.
- Cool feet.
- No pulses in the arteries of your feet.
Severe cases
If the blood supply is very much reduced, then you may develop pain even at rest, particularly at night when the legs are raised in bed. Ulcers (sores) may develop on the skin of your lower leg if the blood supply to the skin is poor. In a small number of cases, gangrene (death of tissue) of a foot may result. This is usually preventable (see below).
How is peripheral arterial disease diagnosed?
The diagnosis is usually made by the typical symptoms. A simple test that your doctor may do is to check the blood pressure in your ankle and compare this to the blood pressure in your arm. If the blood pressure in your ankle is much different to that in your arm then this usually means that one or more arteries going to your leg, or in your leg, are narrowed.
More sophisticated tests are not needed in most cases. They may be done if the diagnosis is in doubt, or if surgery is being considered (which is only in the minority of cases). For example, A CT scan, an MRI scan, or an ultrasound scan of the arteries can build up a 'map' of your arteries, and show where they are narrowed.
What is the outlook (prognosis) for peripheral arterial disease?
Studies that have followed-up people with PAD have shown that:
- Symptoms remain stable or improve in about 15 out of 20 cases.
- Symptoms gradually become worse in about 4 out of 20 cases.
- Symptoms become severe in about 1 out of 20 cases.
So, in most cases, the outlook for the legs is quite good. However, if you have PAD it means that you have an increased risk of developing atheroma in other arteries. Therefore, you have a higher than average risk of developing heart disease (such as angina or a heart attack), or of having a stroke. The main concern for most people with PAD is not that they might need an amputation - but the increased risk of having a heart attack or stroke.
The chance of developing severe PAD (and heart disease, or a stroke) is much reduced by the self help measures and treatments described below.
What 'self help' measures can I do?
Stop smoking
If you smoke, stopping smoking is the single most effective treatment. Stopping smoking increases walking distance by two or threefold in over 8 out of 10 people with PAD. (Stopping smoking also greatly reduces your risk of having a heart attack or stroke.)
See your practice nurse for help if you find it difficult to stop smoking. Nicotine gum or tablets to help you stop may be an option. There are also other medicines that are sometimes prescribed to help people stop smoking.
Exercise regularly
Regular exercise encourages other smaller arteries in the legs to enlarge and improve the blood supply. If you exercise regularly, there is a good chance that symptoms will improve, and the distance that you can walk before pain develops will increase.
Walking is the best exercise if you have PAD. Regular exercise means a walk every day, or on most days. Walk until the pain develops, then rest for a few minutes. Carry on walking when the pain has eased. Keep this up for at least 30 minutes each day, and preferably for an hour a day. The pain is not damaging to the muscles.
Other exercises such as cycling and swimming will also help you to become fit, and are good for the heart. But, these should be done in addition to walking as walking has been shown to be the best exercise to improve symptoms of PAD.
Research studies have shown that - if you stop smoking, and exercise regularly, then symptoms of PAD are unlikely to become worse, and they often improve. Your risk of developing heart disease or a stroke will also be reduced.
Lose weight if you are overweight
Losing weight reduces the demands on the heart and leg muscles and reduces the risk of forming atheroma.
You should eat a healthy diet
This is the same as advised to prevent heart disease. This reduces the chance of atheroma forming. A practice nurse or dietician may advise you on how to eat a healthy diet. Also, another page in this series called 'Healthy Eating' gives details. Briefly, a healthy diet means:
- AT LEAST five portions, and ideally 7-9 portions, of a variety of fruit and vegetables per day.
- THE BULK OF MOST MEALS should be starch-based foods (such as cereals, wholegrain bread, potatoes, rice, pasta), plus fruit and vegetables.
- NOT MUCH fatty food such as fatty meats, cheeses, full-cream milk, fried food, butter, etc. Use low fat, mono-, or poly-unsaturated spreads.
- INCLUDE 2-3 portions of fish per week. At least one of which should be 'oily'.
- If you eat meat it is best to eat lean meat, or poultry such as chicken.
- If you do fry, choose a vegetable oil such as sunflower, rapeseed or olive oil.
- Try not to add salt to food, limit foods that are salty such as processed foods.
Alcohol
A small amount of alcohol (1-2 units per day) may help to protect you from cardiovascular diseases. One unit is in about half a pint of normal strength beer, or two thirds of a small glass of wine, or one small pub measure of spirits. However, too much alcohol can be harmful. Men should drink no more than 21 units per week (and no more than four units in any one day). Women should drink no more than 14 units per week (and no more than three units in any one day).
Take care of your feet
Try not to injure your feet. Injury may lead to an ulcer or infection developing more easily if the blood supply to the feet is reduced. Do not wear tight shoes or socks which may reduce blood supply. Tell your doctor if you have any foot injury, pain in a foot when you are resting, or any marked change in skin colour or temperature in either of your feet.
What are the treatments for peripheral arterial disease?
The self-help measures above are the most important part of treatment. In addition, medication is often advised. Surgery is only needed in a small number of cases.
Medicines
- Aspirin is usually advised. A daily low dose (75 mg) is usual. This does not help with symptoms of PAD, but helps to prevent blood clots (thrombosis) forming in arteries. This is an uncommon complication of PAD. However, as mentioned, people with PAD have a higher than average risk of developing a heart attack or stroke. A daily low dose of aspirin reduces this risk too. If you cannot take aspirin then alternatives such as clopidogrel and dipyridamole may be advised.
- A 'statin' medicine is usually advised to lower your cholesterol level. This helps to prevent a build-up of atheroma.
- If you have diabetes then good control of the blood glucose level will help to prevent PAD from getting worse.
- If you have high blood pressure then you will normally be advised to take medication to lower it.
- Other medicines are sometimes used to try to 'open up' the arteries. For example, cilostazol and niftidrofuryl. One may be tried and may help. However, they do not work in all cases. Therefore, there is no point in continuing with these medicines if you do not notice an improvement in symptoms within a few weeks.
Surgery
Most people with PAD do not need surgery. Your GP may refer you to a surgeon if symptoms of PAD become severe, particularly if you have pain when you are resting. Surgery is considered a last resort. Surgery is not easy and not without possible complications. There are three main types of operation for PAD.
- Angioplasy is where a tiny 'balloon' is inserted into the artery and 'blown up' at the section that is narrowed. This widens the affected segment of artery. This is only suitable if a short segment of artery is narrowed.
- Bypass surgery is where a graft (like a flexible pipe) is connected to the artery above and below a narrowed section. The blood is then diverted around the narrowed section.
- Amputation of a foot, or lower leg, is needed in a small number of cases. It is needed when severe PAD develops, and a foot becomes gangrenous due to a very poor blood supply.
Further help and information
British Heart Foundation
14 Fitzhardinge Street, London W1H 6DH
Tel (Heart Information Line): 08450 70 80 70 Web:
www.bhf.org.uk
The Circulation Foundation
Web:
www.circulationfoundation.org.ukPublishes a number of patient information pages to help identify and treat vascular illness. It also funds research into the prevention and causes of vascular disease.
©EMIS and PIP 2006
