What is Ischemic Stroke?
When a blood vessel that supplies blood to the brain is blocked by a blood clot, ischemic stroke follows. There are two main ways a blood clot can occur:
- When a clot forms in a narrow artery and completely blocks the artery, this is called thrombotic stroke.
- When a clot from another place in the blood vessels of the brain or body breaks off and travels through the blood stream to block a smaller artery, this is called embolic stroke
Ischemic strokes can result from atherosclerosis, a condition that clogs arteries within the brain or arteries in the neck that supply blood to the brain. Substances like fat and cholesterol build up on the walls of the arteries and form a sticky substance called plaque. Over time, plaque builds up and makes it difficult for blood to flow properly, which can lead to a blood clot.
Blood clots that form in the heart or other parts of the body can also cause ischemic strokes. When these clots travel through the blood stream and get struck in the smaller arteries in the brain this is known as cerebral embolism.
Causes of Ischemic Stroke
Ischemic stroke can be caused by several different kinds of diseases. According to the National Stroke Association, the most common problem is narrowing of the arteries in the neck or head. This is most often caused atherosclerosis, or gradual cholesterol deposition. If the arteries become too narrow, blood cells may collect and form blood clots.
These blood clots can block the artery where they are formed (thrombosis), or can dislodge and become trapped in arteries closer to the brain (embolism). Another cause of stroke is blood clots in the heart, which can occur as a result of irregular heartbeat (for example, atrial fibrillation), heart attack, or abnormalities of the heart valves. While these are the most common causes of ischemic stroke, there are many other possible causes. Examples include use of street drugs, traumatic injury to the blood vessels of the neck, or disorders of blood clotting.