The factors responsible for transient ischemic attack and ischemic stroke are the same. Ischemia is the medical term for a decrease in the blood supply of cells to blood and oxygen.
Ischemic stroke occurs when there is obstruction of the arteries supplying the brain. This obstruction can result from narrowing (stenosis) of the arteries, which disrupts blood flow and creates areas of turbulence that can lead to the formation of a blood clot (thrombus). Such a clot can form in an artery supplying the brain or form elsewhere in the body and migrate to the brain to lodge in a narrowed area of a cerebral artery.
A particle that circulates in the blood is called an embolus, and a blood clot that circulates a thromboembolic disease. Localized or circulating blood clots are the leading causes of stroke and TIA. The most common sources of brain emboli causing stroke are
(1) carotid arteries at the neck.
(2) the heart.