How Atherosclerosis Causes Half of All Strokes
How Atherosclerosis Happens
Atherosclerosis occurs in the arteries of the brain the same way it does elsewhere in the body:
- The inner layer of arteries (the endothelium) is damaged by high cholesterol, smoking, or high blood pressure.
- Damaged endothelium allows LDL ("bad") cholesterol to enter the artery wall, where it accumulates.
- The body sends a "clean-up crew" of white blood cells and other cells to the artery, to digest the LDL.
- Over years, ongoing cholesterol buildup -- and the response to it -- creates a bump on the artery wall called a plaque.
Most commonly, the plaque grows slowly, never causing a problem. In fact, most are never discovered. The arteries in the brain adjust to the slow narrowing, and no symptoms occur.
However, for unclear reasons, plaques can also become inflamed and unstable. If a plaque ruptures, the dangerous material in its center is exposed to blood flowing by. As a result, a blood clot forms, which can rapidly block the artery. The brain tissue downstream is starved for blood and nutrients, and dies within hours.
Risk Factors for Atherosclerosis and Stroke
As a cause of strokes, heart attacks, or other diseases, atherosclerosis has the same risk factors. Get to know them:
- High blood pressure (the most important risk factor for stroke)
- Cigarette smoking
- Abnormal cholesterol levels
- Diet high in saturated or trans fats, low in fruits and vegetables
- Physical inactivity
The best way to prevent a stroke is to control these risk factors. If you've already had a stroke or other form of atherosclerosis, reducing your risk is even more important.
Atherosclerosis, Strokes, and 'Clot-Busters'
Most strokes are caused by a sudden blood clot -- which itself is caused by atherosclerosis. If given quickly, "clot-busting" drugs can actually reverse some strokes.
The clot-buster (called tissue plasminogen activator, or tPA) must be given within three hours of the first symptoms of stroke to be most effective. It can be given up to six hours after the stroke if administered directly into the blockage area. This procedure is done primarily at bigger hospitals. Unfortunately, most people don't make it to the hospital quickly enough after experiencing symptoms, and tPA is underused.
If you have any symptoms of stroke, don't hesitate: call 911 immediately. It's your best chance at a good outcome from stroke.
But waiting out stroke symptoms is a losing proposition. Start reducing your risk factors for stroke today, and you'll be protecting yourself from all complications of atherosclerosis.