What You Need to Know About Ischemic Strokes
Jeffrey H. Dover
Strokes are serious medical conditions that occur nearly 800,000 times a year in the United States. Approximately 137,000 people die from them annually, but even those who are lucky enough to survive a stroke are often permanently affected. Up to 30 percent of stroke survivors lose their independence because of permanent disability.
Though there are several types of stroke that a person can experience, ischemic strokes occur most often. According to the Mayo Clinic, approximately 90 percent of strokes can be classified as ischemic strokes.
The term "lacuna" means empty space. If the small arteries within the brain are narrowed by artherosclerosis or a small blood clot, the blood supply is blocked and causes the brain tissue to die (infarction). Though the blood vessels affected by this form of stroke are generally small compared to those affected by thrombotic stroke, they penetrate much deeper within the brain itself.
When a blood clot (thrombus) forms in one of the arteries that supply your brain with blood, this type of ischemic stroke is said to have occurred. Clots typically form in areas damaged by artherosclerosis (hardening of the arteries), and often one of the two carotid arteries is affected. Sometimes called cerebral thrombosis or cerebral infarction, approximately half of all strokes are classified as this type.
This kind of stroke occurs when a blood clot or a piece of artherosclerotic plaque (calcium and cholesterol deposits on the inside wall of the heart of artery) breaks loose and travels (embolism) through open arteries to lodge in an artery of the brain. It may be caused by a blood clot that forms in the heart due to an abnormal heart rhythm such as atrial fibrillation. Another possible cause of embolic strokes is due to plaque forming in a major artery that leads to the brain, such as the carotid arteries.