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ABC of Vascular Disease

Intermittent Claudication

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1. What is intermittent claudication?
Intermittent claudication (IC) is pain in the muscles of the leg which only comes on with exercise and which is relieved by resting.

2. What causes intermittent claudication?
When you exercise the muscles of the leg they need more blood to work properly.  This blood flows in the arteries from heart to the muscles in the leg.  If these arteries are narrow or even blocked not enough blood reaches the muscles and the muscles "complain" by producing pain (see haemodynamics)

3. What causes the arteries to become narrowed?
Arteries tend to "furr up" as you get older and the rate at which they do so is different for each person (see atherogenesis).  Smoking increases the rate at which arteries become narrowed and once the narrowing is established the artery cannot easily be opened up again.  If artery is more than 3/4 narrowed it is unable to carry the normal amount of blood and it is only then that you start to notice symptoms.  All the arteries in the body are affected to a greater or lesser degree but arterial disease in the arteries to the vital organs such as the heart itself, the brain, and the kidneys is obviously more serious.

4. What happens if the artery blocks completely?
It depends on where the artery is and how many other arteries it is connected to.  In some cases the artery my block completely and other arteries can take over the work of supplying blood (collateral arteries).  In other cases when the artery blocks no blood can get through and the part of the body supplied by that artery is starved of blood and the cells die: a process called infarction.  This is what happens in a heart attack when the muscle of the heart (myocardium) loses its blood supply and dies giving a myocardial infarction (MI).  The leg has a good set of collateral arteries and can usually tolerate a blockage in one of the main arteries.  More than one blockage is more serious and may result in infarction of the leg and infection (gangrene).

5. What do I do if I think I have intermittent claudication?
The first thing to do is to see your GP and discuss your symptoms.  If your GP agrees it is worth seeing a specialist and having measurements of the blood pressure in your legs done to confirm the diagnosis.

6. How can intermittent claudication be treated?
In many cases the problem is self-limiting because the collateral arteries slowly increase in size over several months and allow more blood to reach the muscles.  However, intermittent claudication is a warning sign that the arteries are being damaged.  There are a number of other common factors which aggravate arterial disease and these should be looked for and treated if found:

bulletSmoking
bulletDiabetes
bulletHigh blood pressure
bulletHigh blood fat (cholesterol)

Provided that you don't have chest pain or severe shortness of breath on exercise (both signs of heart disease) then regular daily exercise is recommended for people with claudication because

bulletIt improves the development of collateral arteries
bulletIt helps with reducing weight (especially if you've had to stop smoking)
bulletIt improves cardiac fitness

Aspirin tablets, when taken at lower than the normal dose will reduce the stickiness of the blood and, although they do not have any effect on claudication, they do reduce the risk of the arterial disease from getting worse and causing future complications.

7. What if these first line measures do not work?
Most people find a significant improvement but if the problem persists or worsens then it may be necessary to consider more radical treatment.  For this your GP will need to refer you to a vascular surgeon.  Before the surgeon can advise you on what treatment options are possible you will need to have more detailed tests to identify exactly which arteries are affected and how badly.  There are two commonly used tests:

bulletDuplex ultrasound
bulletAngiography

Duplex ultrasound is a special form of ultrasound that can look inside the body and can also "see" the blood moving in the arteries and veins.  It is non-invasive and painless and is done as an outpatient test.

Angiography involves taking x-rays of the arteries and to show them up a special dye needs to be injected into the artery through a needle.  Angiography produces very good pictures of all the arteries but is a more invasive procedure and normally you need to be admitted to hospital for a day or so (angiogram).

8. What are the surgical options for treating intermittent claudication?
There are two main options for the surgical treatment of intermittent claudication:

bulletAngioplasty
bulletArterial bypass

Angioplasty is a minor procedure, similar to an angiogram, that does not require a full anaesthetic and is performed under x-ray guidance.  Angioplasty is only suitable for some types of blocked or narrowed arteries (angioplasty).  

Arterial bypass is a major procedure that involves an operation to place a bypass graft across the blocked artery.  Arterial bypass cannot be done using local anaesthetic.  Arterial bypass is reserved for when other methods are not possible or have failed and where there are severe symptoms (arterial bypass).

S.R.Dodds 2006

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