From a presentation by Christopher Cunningham, MD McLeod Vascular Associates
There are 3 types of strokes: hemorrhagic, caused by bleeding; embolic, when a solid piece of plaque breaks off and blocks blood to your brain; and the embolic stroke triggered in your carotid artery. McLeod Vascular Surgeon Christopher Cunningham, MD, explains the carotid embolic stroke:
Here is an overview of Dr. Cunningham’s remarks:
The carotid arteries run up and down in your neck, taking blood from the heart to the brain. They are about as big as an index finger. For a number of reasons, the carotid artery is a magnet for atherosclerosis (blockages from plaque).
Arteries are like pipes. And if your plumbing went from a 2-inch pipe to a “Y” with two 1-inch pipes, it would be a very orderly flow. But in your neck, the artery comes from the heart, then widens and splits into 2 branches, with one continuing on to your brain. That’s the only place in the human body where there is a natural bowing out of the artery.
In this carotid bulge there are special receptors that help the brain determine things like, CO2 level, PH of the blood, asking “Do I need to tell the body to breathe more deeply to get more oxygen? Or is there something else I need to tell the body to do.”
Here’s another way to think about the carotid bulge. If you want to taste homemade chicken soup, first you give it a big stir. If not, you’ll have bones on the bottom and broth on the top. Blood normally flows in a smooth (laminar) non-mixing, orderly flow.
But when it hits the carotid bulb, it mixes like stirring that soup. Then, blood goes on to you brain. So for every heartbeat you’ve had since you’ve been born, it’s been, “smooth (from the heart to the carotid bulb), turbulent in the bulb, and smooth from the bulb to the brain.
People tend to develop cholesterol and plaque that fill your artery. If the carotid artery is as big as my finger, the bulb is the size of my thumb. I have people everyday that have a clear artery from the heart to the bulb, wide open from the top of the bulb to the heart, but 99% blocked in the bulb.
As the artery gets narrower, the pressure increases. A high velocity jet of blood runs past the soft clogging material. And if pieces get broken off, that’s when you suffer a stroke.
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