Ischemic stroke is caused by the blockage of the arteries to the brain. Ischemia or severe reduction of blood flow makes the brain cells weak and they may eventually die if the blood flow could not be restored.
The two main types of ischemic stroke are thrombotic and embolic. Thrombotic stroke, also known as cerebral thrombosis or cerebral infarction, occurs when the cerebral arteries are blocked due to a blood clot. This kind of ischemic stroke accounts for almost 50% of all kinds of strokes. Embolic stroke is caused by a clot or embolus which originated outside the brain. The embolus then travels until it will become lodged which restricts the blood flow to the brain.