Intermittent Claudication is caused by narrowing or blockage in the main artery taking blood to your leg (femoral artery). This is due to hardening of the arteries (atherosclerosis). The blockage means that blood flow in the leg is reduced. Blood circulation is usually sufficient when resting, but when you start walking the calf muscles cannot obtain enough blood. This causes cramp and pain which gets better after resting for a few minutes. If greater demands are made on the muscles, such as walking uphill, the pain comes on more quickly.
Claudication usually occurs in people aged over fifty years; however it can occur much earlier in people who smoke and those who have diabetes, high blood pressure or high levels of cholesterol in the blood.
Unfortunately, the blockage which causes the claudication will not clear itself, but the situation can improve. Smaller arteries in the leg may enlarge to carry blood around the block in the main artery, this is called collateral circulation. Many people notice some improvement in their pain as the collateral circulation develops. This normally happens within six to eight weeks of the start of the claudication symptoms.
How is Claudication detected?
A blockage in the circulation can be detected by examining the pulses and blood pressure in the legs. A blockage will lead to loss of one or more pulses in the leg. The blood pressure in your feet is measures using a handheld ultrasound device called a continuous wave Doppler.
The blood pressure in the foot can be measured and compared with arm blood pressure (which is usually normal). This measurement is called the ABPI (ankle brachial pressure index) and is expressed as a ratio. The ABPI provides an objective measure of the lower limb circulation.
Claudication is not usually limb threatening and it is not necessary to treat it surgically if the symptoms are mild. Claudication often remains stable, with no deterioration in walking distance over long periods. However if your symptoms worsen, there are treatments available which you can discuss with your vascular surgeon.
General measures to improve walking distance include stopping smoking, taking more exercise and making sure you are not overweight. Blood tests to rule out other causes of atherosclerosis are often done. These will include a blood sugar test to exclude diabetes, thyroid and kidney function tests and a cholesterol test. You may be started on medication like aspirin or clopidogrel which are too be taken lifelong.
There are three approaches to treating the claudication itself:
Exercise has been shown to more than double walking distance.. If this is not available, a brisk (the best you can do) walk three times a week lasting thirty minutes will normally noticeably improve walking distance over three to six months.
Angioplasty (stretching the artery where it is narrowed with a balloon) may help to improve walking distance for some people. Angioplasty is usually limited to narrowings or short complete blockagesin the artery but can be done for longer blockages with use of stents.
Bypass surgery is usually reserved for longer blockages of the artery, when the symptoms are significantly worse. There may be very short distance claudication, pain at rest, ulceration of the skin in the foot, or even gangrene in the foot or toes.
What is the risk of losing my leg?
Very few patients with intermittent claudication will ever be at risk of losing a leg through gangrene. It is the vascular surgeon’s job to prevent this outcome at all costs. If there is thought to be any risk to the limb a vascular surgeon will always act to save the leg if at all possible. You can minimise the risk of progression of your symptoms by following the advice below. It is the simple measures which are the most effective. The vast majority of patients do not need x-ray or surgical procedures to treat their symptoms.
How can I help myself?
There are several things you can do which can help. The most important are to stop smoking and take regular exercise. If you are a smoker, you should make a determined effort to give up completely. Tobacco is particularly harmful to claudicants for two reasons:
Smoking speeds up the hardening of the arteries, which is the cause of the trouble
Cigarette smoke prevents development of the collateral vessels which get blood past the blockage.