Cardiac Conditions & Diseases

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What Is Peripheral Arterial Disease?

Peripheral arterial disease (P.A.D.) occurs when plaque (plak) builds up in the arteries that carry blood to your head, organs, and limbs. Plaque is made up of fat, cholesterol, calcium, fibrous tissue, and other substances in the blood.

When plaque builds up in arteries, the condition is called atherosclerosis (ATH-er-o-skler-O-sis). Over time, plaque can harden and narrow the arteries. This limits the flow of oxygen-rich blood to your organs and other parts of your body.

P.A.D. usually affects the legs, but also can affect the arteries that carry blood from your heart to your head, arms, kidneys, and stomach. This article focuses on P.A.D. that affects blood flow to the legs.

The illustration shows how P.A.D. can affect arteries in the legs. Figure A shows a normal artery with normal blood flow. The inset image shows a cross-section of the normal artery. Figure B shows an artery with plaque buildup that’s partially blocking blood flow. The inset image shows a cross-section of the narrowed artery.

What Causes Peripheral Arterial Disease?

The most common cause of peripheral arterial disease (P.A.D.) is atherosclerosis. The exact cause of atherosclerosis isn't known.

The disease may start when certain factors damage the inner layers of the arteries. These factors include:

  • Smoking
  • High amounts of certain fats and cholesterol in the blood
  • High blood pressure
  • High amounts of sugar in the blood due to insulin resistance or diabetes

When damage occurs, your body starts a healing process. The healing may cause plaque to build up where the arteries are damaged.

Over time, the plaque may crack. Blood cell fragments called platelets stick to the injured lining of the artery and may clump together to form blood clots.

The buildup of plaque or blood clots can severely narrow or block the arteries and limit the flow of oxygen-rich blood to your body.

Information provided by National Heart Lung and Blood Institute