Peripheral Artery Disease

Peripheral Artery Disease (PAD) is an illness that develops over time – often decades – and it is caused by blockages in the arteries of the legs. These blockages are called “plaques”.

Plaque is a substance not normally found within the arteries. However, in patients with PAD plaque can be found lining the walls of the arteries of the legs. Plaque is made up of a number of different elements including fat, cholesterol, calcium and fibrous tissue ⁽¹⁾. With time, the amount of plaque lining the artery walls increases and this leads to clogging of the arteries.  

The illustration below highlights the main differences between a normal artery and an artery filled with plaque. Figure A shows an artery that is free from plaque. This allows blood to flow freely through the artery to the legs without becoming blocked. Figure B demonstrates an artery with plaque lining the arterial wall. The amount of plaque in this illustration is significant and less blood can flow through the artery. This means that the legs will not receive adequate oxygen or other nutrients.

 

There have been a large number of medical studies looking into why plaque builds up in the arteries of certain individuals ⁽²⁾. The medical term for this build up of plaque is “atherosclerosis”. In plain English “athero” means arteries and “sclerosis” means “hardening“. The term atherosclerosis has come to literally mean the hardening of the arteries due to the formation of plaque.

There is general agreement that plaque build up is caused by certain substances and factors that "injure" the artery wall. The main substances and factors that are responsible for causing injury to the arterial wall are ⁽³⁾: 

• Cigarette smoking
• High amounts of fats and cholesterol in the blood
• High blood pressure
• High amounts of sugar in the blood, which leads to diabetes

When the artery wall is injured by one or more of the above factors, the artery wall undergoes many changes, resulting in plaque building up in the wall of the artery. The result is that over time the amount of plaque blocks more and more of the artery so that less oxygen and fewer nutrients can reach the legs.

Plaque buildup is responsible for causing both coronary artery disease and Peripheral Artery Disease. The main difference is that coronary artery disease is a disease of the heart's arteries. Peripheral artery disease usually refers to a disease of the arteries of the legs, but can also be used to describe plaque buildup that occurs in the arteries of the neck and kidneys.

 

PAD is extremely common and affects about 10 million individuals in the United States ⁽⁴⁾ and over 27 million individuals worldwide ⁽⁵⁾.  It becomes more common as one gets older, and by age 65, about 12 to 20 percent of the population has this condition. Diagnosis is important because if plaque has built up in the arteries of the legs then it is likely that plaque has also built up in the arteries of the heart or neck, and this can lead to a heart attack or stroke.

If you're:

• Aged 70 or older;
• Aged 50 or older and have a history of smoking or diabetes
• Younger than 50 and have diabetes and one or more risk factors

You should discuss with your doctor whether you should get checked for PAD.

The symptoms of PAD are caused by the inadequate supply of oxygen and other nutrients to the legs ⁽⁵⁾. When the legs don’t receive enough oxygen, simple activities like walking or climbing stairs may become painful. The pain is often felt in the calf muscles of the legs. Other symptoms include numbness or heaviness in the legs, and patients often notice subtle changes in skin color and the loss of hair from the legs.

One of the common features of PAD is that while symptoms can be painful they often disappear quickly with rest.

Severe PAD involving severely blocked arteries can result in other symptoms, such as the formation of ulcers on the feet that will not heal. Again, the cause of the ulcers is the poor supply of oxygen and other nutrients to the legs. Without these substances, the skin cannot heal.

The ABI is a simple test that compares the blood pressure in your ankle with the blood pressure in your arm. This test shows how well blood is flowing in your legs. The test takes about 10 to 15 minutes to measure both arms and both ankles, and is painless.

Ultrasound is a test that uses sound waves to create a graphical image of an artery. This makes it possible to see if there is plaque within an artery. Doppler ultrasound is a specialized ultrasound system that makes it possible to determine how much blood is flowing through an artery as well as creating a graphical image of the artery. It is a non-invasive test, is not painful, and can help your doctor decide on the severity of your PAD.

A treadmill test can show how severe your symptoms are and what level of exercise induces them. For this test, you walk on a treadmill. This shows whether you have any problems during normal walking.
You may have an ABI test done before and after the treadmill test. This will help compare the blood flow in your arms and legs before and after exercise.

The treatments for Peripheral Artery Disease depend on the severity of your symptoms ⁽⁷⁾.  

Almost all patients with Peripheral Artery Disease will receive blood thinning medications, and your doctor will most likely suggest you make some lifestyle changes – such as changing your diet and regularly exercising. Your doctor may also prescribe medications to help control some of your risk factors for PAD, including high blood pressure and high cholesterol.  

Although the above treatments for PAD may help improve your symptoms in the short term, there is still no cure for PAD. Unfortunately, despite the above treatments, the symptoms of PAD rapidly get worse in a large number of cases and other treatment options are necessary.  

One of these treatment options is a procedure called a Percutaneous Transluminal Angioplasty (PTA) or more simply a balloon angioplasty procedure. The basic concept behind a balloon angioplasty procedure is that a small balloon is inflated inside an artery to open up the artery, improving blood flow. This procedure is safe, much less invasive than traditional surgery, and now standard treatment for most forms of PAD.

You can visit the American Heart Association website (www.americanheart.org) or the National Heart Lung and Blood Institute (NHLBI) website (www.nhlbi.nih.gov) for more information about Peripheral Artery Disease. Your doctor will be able to provide you with additional information.