What is an ischemic stroke most commonly caused by?

An ischemic stroke is predominantly caused by an obstruction in a blood vessel supplying blood to the brain. This obstruction can take the form of plaque buildup, known as atherosclerosis, which narrows the arteries, or it can be due to an embolism, where a clot forms elsewhere in the body and travels to the brain, blocking blood flow. This interruption in blood supply ultimately leads to brain tissue damage as it does not receive the necessary oxygen and nutrients.

The process is critical to understand because recognizing the underlying causes can inform treatment strategies, such as using thrombolytics to dissolve the clot or addressing risk factors for atherosclerosis. While cardiac arrhythmias can contribute to the formation of embolisms that lead to ischemic strokes, the primary mechanism remains the obstruction itself. In contrast, the rupture of a blood vessel indicates a hemorrhagic stroke, and electrical disturbances in neurons relate to different neurological conditions, further clarifying why the primary cause of an ischemic stroke is the blockages created by plaque or emboli.