Peripheral arterial disease (PAD) or peripheral vascular disease (PVD) is characterized by a narrowing of the vessels that carry oxygenated blood to our limbs. This lack of oxygen to our muscles or tissues causes leg pain or claudication. The narrowing is caused by atherosclerosis or a build up of plaque in our arteries or trauma. People who are diagnosed with coronary heart disease are also often diagnosed with PAD or PVD.