Stroke Overview
The most common form of neurovascular disorder is stroke. A stroke interrupts blood flow through the arteries and into the brain, damaging sensitive brain tissue. Depending on the severity of the stroke and the area of the brain affected, severe disability or death can occur, making time and rapid diagnosis the most crucial aspects in stroke care. The American Heart Association (AHA) claims that more than 700,000 Americans suffer a new or recurring stroke every year. More than 150,000 Americans will die this year as a direct result of a new or recurring stroke. That translates to one stroke every 45 seconds and one stroke related death every three minutes in the United States alone.
Of the more than 700,000 strokes that occur in the US annually, 83% of those strokes are ischemic in nature. Ischemic strokes are caused by the presence of an obstruction within a blood vessel supplying blood to the brain. The underlying condition for these types of obstructions is the development of fatty deposits lining the vessel walls. This condition is called atherosclerosis, also referred to as "hardening of the arteries."
The remaining 17% of strokes are classified as hemorrhagic strokes. A hemorrhagic stroke occurs when a weakened or ruptured blood vessel bleeds into the surrounding brain. The blood accumulates and compresses the surrounding brain tissue, resulting in neurological symptoms ranging from moderate to severe. Strokes of a hemorrhagic nature are classified as either intracerebral or subarachnoid.
The two most common forms of weakened blood vessels responsible for hemorrhagic stroke are brain aneurysms and arteriovenous malformations (AVMs). An aneurysm is a ballooning of a weakened vessel that if left untreated can rupture and bleed into the brain. An AVM is a cluster of abnormally formed blood vessels. If left untreated, any one of the abnormally formed blood vessels can rupture and bleed into the surrounding brain.
All forms of stroke are serious and the disabilities associated with them can be severe. The annual costs to service the disabilities of the stroke survivor population are in excess of 55 billion dollars in the US alone, making the direct and indirect costs of stroke one of the largest expenses in the U.S. healthcare system. Despite the significant size and cost of this market, there remain few viable treatment options for the patient.