A stroke occurs when brain tissue is damaged because there is not enough blood flow or oxygen delivery to the brain's cells. Ischemic strokes are a result of lack of blood flow. Different types of ischemic stroke may be due to blockage in the arteries that supply blood to the brain (such as in carotid artery disease), a clot in the smaller arteries in the brain itself (thrombotic stroke), a blood clot from the heart that travels to the brain (embolic stroke), or poor flow to the brain because of heart failure. Damage caused by bleeding into or around the brain is called a hemorrhagic stroke. Hemorrhagic strokes are less common than ischemic strokes but cause a significant number of deaths worldwide. Hemorrhagic strokes are also responsible for severe, nonfatal damage to brain tissue that can leave individuals paralyzed or weak, with difficulty speaking, swallowing, thinking properly, or doing activities of daily living. The June 9, 2010, issue of JAMA contains an article about hemorrhagic stroke.