Peripheral artery disease (PAD)

Peripheral artery disease (PAD) is a circulatory disorder that mainly affects the legs but in rarer cases the arms. The condition can affect one or both sides of the body. It is usually caused by vessel calcification (arteriosclerosis), i.e. blood vessels that have become constricted due to the build-up of deposits.

Most people have no symptoms in the early stages of the disease. Once more advanced, PAD in the legs typically causes pain, for example when walking, which subsides when at rest.

In severe cases, tissue dies due to the lack of oxygen supply. This may lead to amputation as a last resort treatment option.

Milder cases of the disease must also be taken seriously as they can indicate the presence of further cardiovascular diseases.

People with peripheral artery disease (PAD) do not usually have any symptoms in the early stages.

As the disease progresses, they experience pain in their calves, thighs, feet, buttocks or arms. These occur after a certain distance when walking.

If PAD is advanced, the pain can occur after walking less than 200 meters. It disappears again after resting for a few minutes. The medical term given to such walking difficulties is claudicatio intermittens or intermittent claudication.

In the advanced stages of the disease, the pain primarily affects the front of the foot and toes, even when at rest. The symptoms can sometimes be alleviated by pacing up and down.

As a result of the increasingly poor blood circulation, in the late stage of the disease, sudden pain occurs in the affected limbs, which can lead to numbness and ultimately paralysis.

It is also possible to experience a feeling that is often described as “formication” (insects crawling on the skin). Pale, cool skin and a weak pulse that is often no longer perceptible are also typical.

As the blood supply is no longer sufficient, even minor wounds stop healing properly. This leads to the formation of ulcers, especially on the feet. Bedridden PAD patients are at a higher risk of developing pressure sores on their legs.

Gangrene has been recorded in some severe cases. This means that the skin tissue and deeper tissue die. Typical gangrene symptoms include blackened areas on the foot, especially on the toes (“smoker’s leg”).

The most common cause of peripheral artery disease (PAD) is vascular calcification (arteriosclerosis). This is a chronic inflammation of the blood vessels where deposits of cells, blood fats and other substances build up and constrict the bloodstream.

As a result, less blood flows through the arteries and – depending on the severity – the oxygen supply to the affected areas of the body is impaired or completely cut off. The more advanced the arteriosclerosis, the worse the blood supply.

People who smoke are at a higher risk of peripheral artery disease (PAD). Smoking also increases the risk of a more serious outlook.

Other factors that increase the risk of PAD include:

• diabetes mellitus
• older age
• frequent occurrence in the family
• high blood pressure (hypertension)
• high blood lipid levels

Studies show that about 3 to 10 percent of people in industrial nations have peripheral artery disease (PAD).

The probability of developing the disease increases with age: 15 to 20 percent of people aged 70 or above have PAD.

In the early stages of peripheral artery disease (PAD), the blood vessels are not very calcified and are barely constricted, allowing the body to still be sufficiently supplied with oxygen and nutrients.

As the calcification of the vessels (arteriosclerosis) progresses, so too do the symptoms. First, pain occurs due to the reduced blood flow – initially only when moving but later also at rest.

The reduced blood circulation also impairs wounds’ ability to heal. It is no longer possible for enough nutrients and oxygen to reach wounds, potentially resulting in the formation of chronic wounds and ulcers. These can in turn cause bone inflammation (osteomyelitis).

If the blood supply to the tissue is extremely low or inexistent (ischemia), the tissue dies.

People with an increased risk of peripheral artery disease (PAD) are advised to undergo routine screening even if they have not developed any symptoms.

These include people who smoke, people with diabetes mellitus and people for whom PAD runs in the family.

Among other things, doctors will measure the blood pressure in the arm and ankle. The two results (also known as the ankle-brachial index) are used to determine if the circulation is already impaired.

To diagnose peripheral artery disease (PAD), the doctor will first ask about the symptoms and possible risk factors.

These include lifestyle habits such as smoking and physical exercise, but also existing conditions of close relatives.

A physical examination then follows. Cool, pale or bluish skin and a weak or no longer perceptible pulse are signs of poor blood circulation. Chronic wounds, ulcers or dead tissue, especially on the lower legs, ankles or feet, are further symptoms of the disease.

If the symptoms are not clear, the ankle-brachial index is determined. Doctors use this examination, also known as the ABI test, to measure the blood pressure in the upper arm and at the ankles. The ratio between the two values indicates whether the blood circulation is impaired and can make it possible to diagnose the stage of the disease.

A treadmill test is also carried out: this determines the person’s ability to walk at a treadmill speed of 3.2 kilometers per hour with an incline of 10 to 12 percent. In other words, people walk very briskly and climb 10 to 12 meters within a distance of 100 meters. The ankle-brachial index is measured before and after the exercise. A decrease of 20 percent is a clear indication of PAD.

To determine where and to what extent the arteries are constricted, doctors use imaging techniques such as a special ultrasound (duplex sonography) or x-ray. In the case of the latter, a contrast agent is often injected into the blood vessels to make it easier to see the constricted areas.

There are several ways to treat peripheral artery disease (PAD):

• treatment of pre-existing conditions
• walking exercises and medication
• vascular dilation surgery
• a healthy lifestyle

Treatment of pre-existing conditions

Depending on the PAD risk factors, various measures are possible, including:

• treatment to lower the blood pressure, e.g. through exercise and medication
• medication to regulate the lipid metabolism
• help dealing with diabetes: the better the blood sugar levels are regulated, the less susceptible the blood vessels are to calcification.

Walking exercises and medication

People with PAD who can only walk a limited distance without pain suffer from “intermittent claudication”. At this stage, structured walking exercises are used. This is the most important non-medication-based treatment. It is effective if the exercises are performed three times a week for 30 to 60 minutes. If the exercises are initially done under the guidance of experts for at least 3 months, people can then do them independently.

Doctors can also prescribe medication to promote blood circulation. This is primarily done if exercise therapy has not helped.

Vascular dilation surgery

If PAD vastly restricts people’s lifestyle and neither walking exercises nor medication has sufficiently alleviated the symptoms, minimally invasive surgeries are possible.

Doctors insert a balloon into the blood vessel using a catheter and expand the constricted area (vascular dilation). They can also insert a stent or create a bypass.

A stent is a tube-like implant that expands the constricted artery to maintain the blood flow. To create a bypass, a blood vessel is usually taken from another part of the body and inserted at the constricted point. This allows the blood to avoid (bypass) the constricted area.

If body tissue has already died, life-threatening infections can occur. Depending on how much tissue is affected, amputation may be necessary.

A healthy lifestyle

Doctors also advise people with PAD to lead a healthy lifestyle. This includes not smoking, a balanced diet and regular exercise. This also helps prevent other cardiovascular diseases such as a stroke or heart attack.

Those who struggle to quit smoking can use nicotine replacement therapy to wean themselves off cigarettes or have their doctor refer them to a smoking cessation program.

As peripheral artery disease (PAD) is a chronic disease, regular monitoring is important.

The first aftercare examination should take place 3 months after the initial treatment. If the symptoms have not improved sufficiently during this period or the disease has continued to progress, further medical treatment is possible.

If the treatment is working well, an annual check-up by a family doctor then suffices.