Arteriosclerosis is also known as hardening of the arteries. This means that arteries which carry blood to the body and organs are no longer patent. When the opening of the artery is clogged with plaque, blood flow is diminished and tissue at the site is starved. Arteriosclerosis is most concerning when it clogs small blood vessels like those in the brain, the heart and the lower extremities. Long standing high blood pressure can increase the likelihood of this condition.