Peripheral Artery Disease

The circulatory system contains two types of blood vessels namely veins and arteries. The main function of these vessels is to carry blood to various organs. The arteries carry oxygen and nutrient-rich blood from heart to body cells. Peripheral artery disease (PAD), also known as peripheral vascular diseases is a common disease of arteries. It is caused by accumulation of fatty material, plaque, within the vessels. This condition is known as atherosclerosis, or arteriosclerosis, or hardening of arteries. During this gradual process, the arteries become blocked and narrowed. When arteries of heart are affected, it results in coronary heart disease/coronary artery disease.

Causes of PAD

The most common cause of PAD is atherosclerosis. This condition can reduce the ability of arteries to supply blood and oxygen to body tissues, when more oxygen supply is needed during certain activities such as exertion. There may be complete obstruction of artery by embolus or thrombus (forms of blood clots), which may result in death of tissue (tissue necrosis). Intermittent claudication and exertional angina result from insufficient supply of blood and oxygen to tissues. Heart attack and stroke result from tissue necrosis. Atherosclerosis mainly affects the arteries of heart. However, this disease can affect all the arteries throughout body. When it affects the arteries supplying blood to the legs, the condition is known as peripheral artery disease. Some other causes of PAD are blood clotting disorders, infection, injury to the legs or unusual anatomy of ligaments.

Risk Factors for PAD

PAD is a common circulatory condition that affects a number of people. Some of the factors that increase a risk of developing PAD are:

• Diabetes
• Smoking
• High cholesterol
• High blood pressure
• Obesity (Body mass index more than 30) and physical inactivity
• Excess levels of homocysteine
• Increasing age. People above the age of 50 years are at higher risk of developing PAD
• Family history of PAD, stroke or heart disease
• Chronic renal failure

A person who smokes or has diabetes is at highest risk of developing some complications from PAD, such as gangrene in a leg because of reduced blood flow.

Symptoms of PAD

Many people suffering from PAD experience no symptoms. For those who experience some symptoms, intermittent claudication (leg pain while walking) and rest pain are the most common symptoms. Intermittent claudication is characterized by cramping in legs or arms and muscle pain. Pain triggers by certain activities such as walking, exercise, etc. Calf muscle is the most common location of intermittent claudication. Rest pain results from inadequate blood and oxygen supply to the lower extremities while resting. This severe pain typically affects the feet while the patient is in supine position (lying down, face up).

Some other signs and symptoms of PAD are numbness of extremities, painful cramping in hips, calf muscles or thigh while walking or climbing stairs, feeling of coldness in feet or legs, weakness and atrophy, changes in color of the feet, hair loss over the dorsum of the feet and thickening of toenails, painful ulcers or gangrene in tissues, typically in the toes.

Diagnosis of PAD

Diagnosis of PAD includes physical examination and some investigations. During the physical examination, the doctor looks for signs of PAD such as weak or absent pulse in the extremities, changes in blood pressure in the lower extremities during exercise or rest, whooshing sounds (bruits) over the arteries that can be heard with a stethoscope and changes in skin color and nails. Ankle-brachial index (ABI) is the most common test used for the diagnosis of PAD. Special ultrasound imaging techniques such as duplex scanning or Doppler ultrasound can help to evaluate the blood flow through the vessels. Catheter angiography, Computerized Tomography Angiography (CTA) or Magnetic Resonance Angiography (MRA) are other techniques used to detect narrowing of the blood vessels. Some blood tests such as determination of levels of blood cholesterol, C-reactive protein and homocysteine are also helpful to diagnose PAD.

Treatment of PAD

Treatment of PAD focuses on managing the symptoms and stopping the progression of atherosclerosis. The doctor prescribes certain medications to prevent the formation of blood clots, reduce cholesterol levels, blood pressure and control pain and other symptoms. In some cases, angioplasty or surgery is needed to treat PAD. In addition to medications, some exercise-training program is advised by the doctor.