What is peripheral arterial disease (PAD)?
Peripheral arterial disease (PAD) -- also known as peripheral vascular disease, atherosclerosis or hardening of the arteries -- is a disorder that occurs in the arteries of the circulatory system. Arteries are the blood vessels that carry oxygen and nutrient-rich blood from the heart to all areas of the body. PAD occurs in the arteries that carry blood to the arms and legs.
Healthy arteries have a smooth lining that prevents blood from clotting and promotes steady blood flow. In PAD, the arteries slowly become narrowed or blocked when plaque gradually forms inside the artery walls. Plaque is made of excessive fat, cholesterol and other substances floating through the bloodstream, such as inflammatory cells, proteins and calcium. If the arteries become narrowed or blocked, blood cannot get through to nourish organs and other tissues, causing damage to the tissues and eventually tissue death.
The rate at which PAD progresses varies with each individual and depends on many factors, including where in the body the plaque has formed and the person’s overall health.
What are the risk factors for PAD?
An individual is at risk for developing PAD when one or more of these risk factors are present:
- Age: In the United States, people aged 50 and older have an increased risk for PAD
- Race: African Americans have a two-fold higher risk of developing PAD compared to other groups
- History of heart or blood vessel disease: A personal or family history of heart or blood vessel disease may be an indicator for PAD
- High blood pressure (hypertension)
- High cholesterol (hyperlipidemia)
What are the conditions associated with PAD?
If left untreated, patients with PAD can develop serious health problems, including:
- Heart attack: permanent damage to the heart muscle caused by a lack of blood supply to the heart for an extended time
- Stroke: interruption of the blood flow to the brain
- Transient ischemic attack (TIA): a temporary interruption in the blood supply to the brain)
- Renal artery disease or stenosis: a narrowing or blockage of the artery that supplies blood to the kidney
- Amputation: the removal of part or all of the foot or leg (rarely the arm), especially in people who also have diabetes
Development of Peripheral Arterial Disease
Your arteries are shaped like hollow tubes. Inside, they are smooth and elastic, allowing blood to flow freely.
Peripheral arterial disease starts when fatty deposits start streaking the blood vessel walls. The fatty matter builds up. This causes slight injury to your blood vessel walls. In an attempt to heal itself, the cells release chemicals that make the walls stickier. Other substances floating through your bloodstream start sticking to the vessel walls, such as inflammatory cells, proteins and calcium. The fat and other substances combine to form a material called plaque or atherosclerosis. The plaque builds up and narrows the artery.
Over time, the inside of the arteries develop plaques of different sizes. Many of the plaque deposits are hard on the outside and soft and mushy on the inside. The hard surface can crack or tear, exposing the soft, fatty inside. When this happens, platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. The artery narrows further. Symptoms occur.
The artery may become completely blocked by plaque or a blood clot that lodges in a narrowed artery. If this occurs, the tissue below the blockage is permanently damaged and may die (gangrene). This most often occurs in the toes and feet.