Peripheral Arterial Disease

What is peripheral arterial disease?

Peripheral arterial disease (PAD) happens when the arteries carrying blood to your limbs, usually your legs, become narrowed or blocked, most often because fatty deposits (plaque) build up inside the artery walls. This reduces blood flow to your legs and feet, and can cause pain, particularly when walking. It's treatable, especially when caught early.

What are the symptoms of peripheral arterial disease?

Many people with PAD, perhaps as many as 1 in 5, have no symptoms at all, and over half have symptoms that don't fit the classic pattern. The most common is leg discomfort brought on by activity, known as intermittent claudication: pain, cramping, heaviness or numbness in your calves, thighs or buttocks that starts when you walk or climb stairs and eases within about 10 minutes of resting.

The area of discomfort felt can provide a clue to which artery is affected. For example, pain in your buttock, hip or thigh points to narrowing higher up, in your pelvic arteries, while calf pain points to narrowing in your thigh or knee arteries. In men, PAD affecting these higher arteries can also contribute to erectile dysfunction.

As PAD becomes more severe, other symptoms can develop, including:

• burning or aching pain in your legs, feet or toes even at rest, often worse lying flat and eased by letting your foot hang over the edge of the bed
• hair loss or slower hair growth on your legs, and slower toenail growth
• skin on your legs that looks pale, shiny or bluish, or feels cool to the touch
• sores or ulcers on your feet or toes that heal slowly or not at all
• difficulty feeling a pulse in your foot or leg.

Seek medical care immediately if you notice a sudden change, such as your foot turning very pale, blue, purple or black, feeling cold, or losing feeling or the ability to move it. This can mean a sudden blockage and needs urgent treatment.

What are the causes of peripheral arterial disease and who is at risk?

The usual cause is atherosclerosis: plaque, made of fat, cholesterol and other substances, gradually builds up inside your artery walls and narrows the space blood can flow through.

The plaque's harder outer surface can crack, allowing a blood clot to form around it and narrow the artery further. Less commonly, PAD can be caused by inflammation of an artery, a blood clot, an injury, or unusual anatomy that repeatedly squeezes an artery.

You're at higher risk of PAD if you:

• smoke or have smoked in the past: this is considered the single strongest risk factor
• have diabetes, which raises your risk by around two to four times
• have high blood pressure, high cholesterol or high triglycerides. Your risk is thought to rise by around 5–10% for every 10mg/dL (about 0.26mmol/L) increase in total cholesterol
• have chronic kidney disease
• are aged 50 or over, particularly if you're of Black African or Caribbean heritage/descent
• have a personal or family history of heart or blood vessel disease.

Are there different types of peripheral arterial disease?

PAD is described by where it affects you. Lower-extremity PAD, affecting your legs and feet, is by far the most common form. Upper-extremity PAD, affecting your arms, hands or fingers, is much less common.

PAD also tends to move through recognisable stages over time, though not everyone progresses through all of them:

• asymptomatic PAD, where you have no day-to-day symptoms, sometimes because you've unconsciously limited your activity to avoid discomfort
• chronic symptomatic PAD, with leg discomfort that starts with activity and eases with rest
• chronic limb-threatening ischaemia, where severe blockages cause pain even at rest, non-healing sores, and possibly gangrene; around 12–20% of people diagnosed with PAD reach this stage
• acute arterial occlusion, where a blood clot suddenly blocks blood flow, causing pain, pale or cool skin, and numbness, and needs emergency treatment. Fewer than 1 in 50 people with symptomatic PAD reach this stage.

How is peripheral arterial disease diagnosed?

Diagnosis usually starts with your doctor examining your bare feet and legs to feel for a pulse, so don't be surprised if you're asked to remove your socks. The main test is the ankle-brachial index (ABI), which compares blood pressure at your ankle with blood pressure in your arm. A healthy result is 1.00 or higher; below 0.90 suggests PAD, and below 0.40 suggests it's severe. If your ankle arteries are hard to assess, a similar test can be done at your big toe instead.

Further tests can help confirm the diagnosis and plan treatment, including a vascular (duplex) ultrasound to measure blood flow speed, pulse volume recording, a CT or MRI angiogram to image your blood vessels in detail, and occasionally a catheter angiogram, where a contrast dye is injected directly into your arteries during an X-ray.

How is peripheral arterial disease treated?

Non-surgical treatment

If your PAD is mild or you don't yet have symptoms, lifestyle changes and medicines are usually the main approach, with regular monitoring to catch any progression early.

• stopping smoking is one of the single most effective things you can do
• supervised exercise therapy, typically walking on a treadmill with rest breaks under a healthcare professional's guidance, is usually the most effective form of exercise and is often the first treatment tried
• a heart-healthy diet, such as the Mediterranean or DASH diet, with plenty of vegetables, fruit, nuts, whole grains and legumes
• daily foot care: checking your feet for cracks or sores, washing and drying them daily, avoiding walking barefoot, and wearing well-fitting shoes and socks, since wounds and infections are harder to heal with reduced blood flow.

Medicines commonly used include:

• antiplatelet medicines such as aspirin or clopidogrel, to reduce the risk of blood clots
• cilostazol, a medicine that helps your arteries to relax and allow more blood to flow through, which can let you walk further before pain starts
• statins, to lower cholesterol and help protect against limb loss and cardiovascular death
• blood pressure medicines
• occasionally, a blood-thinning medicine (anticoagulant).

Procedures and surgery

If lifestyle changes and medicines aren't enough, or your symptoms are severe, a procedure to open or bypass the blocked artery may be recommended:

• angioplasty, where a small balloon is used to widen the narrowed artery, sometimes leaving a stent in place to help keep it open
• atherectomy, a minimally invasive procedure using a catheter to remove plaque directly
• endarterectomy, surgery to remove plaque from the artery
• bypass surgery, creating a new route for blood to flow around the blockage, typically used for non-healing wounds, severe pain, or to try to save a damaged leg or foot, or when angioplasty isn't likely to work.

When should I see a doctor?

Contact your doctor if you develop new or worsening leg symptoms, can't manage your usual activities because of leg pain, have pain in your legs at rest, or notice a sore or ulcer on your foot or toe. It's also worth asking to be assessed for PAD if you have risk factors, such as smoking, diabetes or high blood pressure, even without any symptoms.

Get emergency care straight away if you suddenly can't feel or move your foot, or it looks a different colour to your other foot, as this can mean you've suddenly lost blood flow to your leg.