Ischemic stroke can be caused by several different kinds of diseases. 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.
A thrombotic stroke occurs when diseased or damaged cerebral arteries become blocked by the formation of a blood clot within the brain. Clinically referred to as cerebral thrombosis or cerebral infarction, this type of event is responsible for almost 50% of all strokes. Cerebral thrombosis can also be divided into an additional two categories that correlate to the location of the blockage within the brain: large-vessel thrombosis and small-vessel thrombosis. Large-vessel thrombosis is the term used when the blockage is in one of the brain’s larger blood-supplying arteries such as the carotid or middle cerebral, while small-vessel thrombosis involves one (or more) of the brain’s smaller, yet deeper penetrating arteries. This latter type of stroke is also called a lacuner stroke.
An embolic stroke is also caused by a clot within an artery, but in this case the clot (or emboli) was formed somewhere other than in the brain itself. Often from the heart, these emboli will travel the bloodstream until they become lodged and can not travel any further. This naturally restricts the flow of blood to the brain and results in almost immediate physical and neurological deficits.
Who gets it?
Ischemic stroke accounts for about 80% of all strokes. The risk of ischemic stroke rises as you get older (60 or more years old). At each age, stroke is more common in men than women and it is more common among black people than white people (People that are black are more likely to have uncontrolled high blood pressure). Diabetes, high blood pressure and smoking put you at higher risk of having a stroke.
Learn more about the causes of Ischemic stroke.