As we move up into the brain, the last type of thing that we often see is actual what we call lacunar strokes, which is essentially a stroke of the tiniest little arteries in the brain. And so what you end up having is you have these big pipes that come up and they split into smaller pipes and off the smaller pipes coming to those little feathery vessels that supply very important areas of the brain and the brainstem. And things like diabetes, high blood pressure, high cholesterol are very hard in those arteries and they can collapse. And essentially what they do is they scar up and then they'll block off. And we called those lacunar strokes. And those account for our large percentage of the strokes that we see. It's interesting, the same pathology can actually occur, and instead of that artery blocking off the scar tissue, makes the artery weak and then the artery ruptures. And so in the same places we see lacunar strokes, this is the same place as where we actually can see hemorrhages in some people. Why some people have hemorrhages and other and other people have lacunar strokes where there's a clot? We don't know exactly why, but that's certainly what happens. And again, the key answer or the key sort of take home message in those cases is prevention, prevention, prevention, and it's blood pressure, blood pressure, blood pressure, cholesterol, diabetes. And so those are the major causes of ischemic stroke that we see, in general, which is cardioembolic often from A Fib, carotid artery stenosis, and then actual strokes from the blood vessels in the brain called lacunar strokes.
Stroke is a major health issue for the United States and the world in general. When we talk about stroke, I find that often my patients have difficult time really understanding what a stroke is and there's a lot of misconceptions out there. So first let's talk about what, what a stroke is when a physician is talking about a stroke. We're usually talking about three major different conditions. The first and the most common type of stroke is something called an ischemic stroke. And most of the time when doctors are talking about strokes, this is what they're talking about. An ischemic stroke is where a clot or some type of blockage, actually this could be most commonly a blood clot, but also a cholesterol embolus or cholesterol piece breaks off and comes up into the brain and lands at some point where it blocks an artery. And now that artery can't supply blood to part of the brain. That part of the brain stops working. So people immediately develop symptoms. From my end, I very much pay attention to what type of symptoms or the pattern of symptoms that people have. Because with a stroke, we know how the blood vessels go in the brain and where they go. And so the symptoms have to correlate to a vascular distribution. The longer that blood clot stays there, the more damage happens. Damage starts happening immediately, and over the course of minutes to hours, that damage can become permanent. That's why often when we talk about treating stroke, time is of the utmost importance, and that's something that we will talk more about later when I talk about treatment.
The second type of stroke is something called a hemorrhagic stroke or a brain hemorrhage. With a hemorrhagic stroke, which is much less common than the ischemic type of blood vessel within the brain actually ruptures. Often the biggest risk factor for something like this is high blood pressure, the blood pressure you can imagine causes the blood vessels to wear down and finally they'll rupture. They often rupture in very specific areas. These are very dangerous strokes to have occur because of the blood inside the brain, inside the skull can be lethal. Um, but fortunately this is a type of stroke that actually is becoming less and less common because we're doing such a good job of preventing.
I'd like to talk next about the epidemiology of stroke. If we look at the nation as a whole, we see close to 800 to 900,000 strokes per year. Fortunately what we're seeing though, because of our great efforts and the public's great sort of response is that the incidence of death related to stroke, the number of strokes causing people to die is decreasing. It used to be, approximately four years ago, the struggles, the third leading cause of death. And then it became the fourth leading cause of death. And now it's the fifth leading cause of death. And so we're doing a better job of treating strokes, keeping people alive. And one of the things we have to keep in mind is that despite this decrease in the number of deaths, people are still having strokes and it remains the leading cause of long-term disability. And I think we all sort of have the notion that there are fates potentially even worse than death, where you're left with such disabling problems that life can be very, very difficult. If we look at the stroke types that we have, it's interesting to see what percentage of each stroke really occur. So with ischemic strokes, we're looking at about 88% of all strokes are ischemic strokes. So the vast majority of strokes are ischemic strokes, where a blood clot travels up into the brain, blocks an artery, the brain stops working and injury occurs about 9% of all strokes are related to interest, cerebral hemorrhage. So again, that's where the blood vessel ruptures inside the brain and blood causes injury and presses the brain aside. And then the least common, which is subarachnoid hemorrhage, is about 3%. And the subarachnoid hemorrhage is where an aneurysm, this little bubble, like outpouching ruptures causing sudden onset headache, neck stiffness, and often prolonged hospitalization.
Lastly, the third type of stroke, the least common type of stroke, but also the most dangerous type of stroke is something called subarachnoid hemorrhage. With a subarachnoid hemorrhage, what you have, typically is you have a blood vessel with an aneurysm, an aneurysm is sort of a bubble like outpouching of the blood vessel. And with that bubble outpouching the blood vessel wall gets weak. And actually, it's interesting, with an aneurysm, there are no symptoms. People can't feel an aneurysm generally. The only time in the aneurysm becomes symptomatic is when it ruptures. And the symptom of that is a sudden onset, worst headache of your life. It just hits like this and people can lose consciousness suddenly. And what happens is that blood then spills around the outside of the brain, uh, causing irritation to the skin around the brain called the meninges, which caused the significant pain, headache, neck stiffness. And for those, it often requires coming to the hospital, potentially surgery to clip the aneurysm, and unfortunately often a prolonged stay in the hospital for monitoring.
With A Fib, this is a disease in which the top of the heart fibrillates. So if we look at a heart, and I'm a neurologist, so I'm gonna look at this sort of basically. I think the hardest two chambers, the Atrium and the ventricle. Blood comes into the atrium, the Atrium squeezes the blood into the ventricle, the ventricles, the big muscle squeezes it and it goes to the whole body. And most importantly, the brain. In A Fib, the top just quivers. It's not beating like it should. It's just quivering. But fortunately we've got gravity on our side, so blood comes down to the ventricle, ventricle squeezes it up and you're good to go. Your heart will beat irregularly, which some people can recognize, but many people don't. What the problem is in this condition is that blood then can sort of sit in the nooks and crannies of that atrium. And when it does that, it coagulates. Clots can form. They can be big clots and they get solid cause they've had some time to form. And then gravity is your worst enemy. Gravity, then the clot comes down and the heart squeezes it up, and it goes into the brain and can cause an ischemic stroke. So A Fib is a big deal, and we'll talk later about how that's treated or prevented.
On top of that, we're always looking for other ways to more quickly detect stroke, to get someone tPA faster. And one of the really neat things that's been coming out there, and it's still too early for primetime, but it's coming out, are our actual ambulances with a cat scan in the ambulance. So if someone has a stroke, the paramedics are trained to recognize what a stroke looks like, get someone in the, in the ambulance can actually do a CT scan in the ambulance and then more quickly give them IV tPA in the field rather than having them come into the hospital. So that's a future direction that we may be moving into as well. And then another area that's been an interesting area, it has been some type of neuroprotection trying to find something that can protect the brain, uh, because often the big problem for us is time is, you know, the time it takes someone to get into the hospital time it takes them to get evaluated in the hospital and then get the tPA going. And if there's something that we can give them to help protect their brain during this whole evaluation, that would be really, really wonderful. One last area is trying to look at how we can make IV tPA more effective. And an interesting thing that's been researched and continuing to be researched is using ultrasound to try to augment the tPA. And the idea is if you can locate where the clot is in the artery, you can actually put a device over the skin that's sending ultrasound waves where the clot is, so that as the tPA hits the clot, it can warm into the clot better and break it up more effectively. And so that's another area that's being actively researched that's exciting.
The latest research on stroke has actually probably revolved around the intraarterial treatment or your interventional treatment of stroke. Although there's a few areas we can talk about. With respect to interarterial treatment of stroke, this is one of those things where, generally speaking, we've always thought of ourselves as sort of, you know, slightly behind cardiologists. Cardiologists had been putting stents in the heart and doing interventions angioplasties and the heart for years and years and the type of clot that occurs in the heart at least bear some similarity to the brain. So we've always thought that we could do that, but we've had a hard time really proving that that's been effective for stroke. In the last month there's been an important randomized control study that's come out called Mr. Clean that's shown that intraarterial treatment plus IVTPA may be more effective than just TPA in some patients. This is very exciting for us. And the research has sort of really tended to sort of go along those lines with respect to better devices. So if trying to find the right device, and it's been interesting as we've looked through the different devices that we've used for interventional treatment of stroke, it started off with just intraarterial tPA trying to just give tPA directly to the spot and then came along something called the mercy retriever. And the mercy retriever is literally, it's a corkscrew. I mean, the, the legend is that someone was using, you know, of course grew on a wine bottle. I thought, wait a minute. And so, you know, you of course, grew into the clot and try to retrieve it. Then came something called a device where you actually poke the clot and suction it out. And then came the stent treavers and the notion is that the next step beyond that, it's coming.
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