Arteriosclerosis -- the general hardening and thickening of the arteries -- is responsible for the majority of deaths in the United States. Atherosclerosis is the most common type; other types include focal calcific arteriosclerosis, arteriolosclerosis, and arteriosclerosis obliterans. Regardless of the type, all forms of arteriosclerosis are characterized by a buildup in the arteries -- either of plaque or calcium.