Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Peripheral Artery Disease ?
    ### Response:
    Peripheral artery disease (P.A.D.) is a disease in which plaque 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 the body's arteries, the condition is called atherosclerosis.
    