Most common cause is inflammatory atherosclerosis, where the walls of your arteries become thick and stiff because of the accumulation of fatty and calcium deposits. The deposits are called plaques. The inflammatory plaque is very similar to the oxidative rust of iron pipes clogging up the drainage. When this happens, the flow of blood is limited. In the arteries of the heart it is known as coronary artery disease, in the legs, peripheral arterial disease (PAD). Many patients are unable to differentiate a heart attack and a stroke. Heart attack affects the arterial blood supply to the heart organ located inside your chest whereas stroke is a disease affecting blood supply to the brain within the skull.