http://www.nhlbi.nih.gov/health/dci/Diseases/pad/pad_what.html
National Heart, Lung, and Blood Institute, National Institutes of Health
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. The publication links to more information about P.A.D., including causes, signs and symptoms, diagnosis, treatments, and prevention.