If your doctor suspects a diagnosis of peripheral vascular disease (PVD), they will usually first carry out a physical examination of your leg.

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

• shiny skin
• brittle toenails
• hair loss

The ankle brachial pressure index

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

First, your doctor 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 PVD, 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 doctor will be able to confirm a diagnosis of PVD 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 PVD, 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.

A 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.

Source: NHS Choices, UK (Diagnosing peripheral arterial disease)