If your GP suspects peripheral arterial disease (PAD), they'll first carry out a physical examination of your legs.
PAD can cause various symptoms – some of which your GP will be able spot, but you may not – such as:
- shiny skin
- brittle toenails
- hair loss on your legs and feet
- the pulse in your leg being very weak or undetectable
- leg ulcers
Your GP may also ask about your symptoms and your personal and family medical histories.
The ankle brachial pressure index
The ankle brachial pressure index (ABPI) test is widely used to diagnose PAD, as well as assess how well you're responding to treatment.
While you rest on your back, your GP or practice nurse will measure the blood pressure in your upper arms and your ankles. These measurements are taken with a Doppler probe, which uses sound waves to determine the blood flow in your arteries.
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 one.
However, if you have PAD, the blood pressure in your ankle will be lower because of a reduction in blood supply, so the results of the ABPI would be less than one.
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 to see the effect of physical activity on your circulation, although it usually needs to be done in hospital, as most GP surgeries don't have the facilities to perform this test.
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's uncertainty about the diagnosis – for example, if you have leg pain but your ABPI score is normal
- you don't fit the expected profile of somebody with PAD – for example, you're young and have never smoked
- the restriction of blood supply in your leg is severe enough that treatment, such as surgery, may be required
Additional hospital-based tests that can be used include:
- an ultrasound scan – where sound waves are used to build up a picture of arteries in your leg; this can identify exactly where in your arteries there are blockages or narrowed areas
- an angiogram – where a special liquid known as a contrast agent is injected into a vein in your arm; the agent shows up clearly on a CT scan or MRI scan and produces a detailed image of your arteries
In some cases, the contrast agent may be injected directly into the arteries of your leg, and X-rays may be used to produce the images.