Summer 1995 Volume 4, Number 3

DR. SAMUELS: Stroke is a very, very old problem. Hippocrates called it apoplexy. Not a bad name: It means suddenness. We've used many terms since.

For a long time, doctors used a peculiar term, "CVA" - cerebral vascular accident. This was when the doctors thought strokes were all sort of accidents in the head.

Then the term "stroke" came in - really, a lay person's term. When I came to Boston, my first patient at Boston City Hospital told me that he "took a shock." Not a bad term, "shock." Suddenness: that's the essence.

We're trying to change the term again, trying on a national scale to educate people and primary care doctors to think about this as "brain attack" - analogous in almost every way to heart attack

Everybody knows what to do if, suddenly, they were to get a terrible chest pain - as if an elephant sat on their chest - which went down the left arm and produced a lot of nausea. If somebody in your family had that symptom, you'd call 911, wouldn't you? You'd get them to the hospital.

Yet, when people have attacks of a similar kind affecting the brain, many times people do nothing at all about it. And worse, many doctors don't do anything about it, either.

A stroke is, by definition, a sudden or rapid onset of a neurological deficit of some kind: loss of function on one side of the body, loss of speech, loss of vision to one side of space, loss of sensation to one side of the body - caused by a blood vessel disease.

In one kind, a blood vessel has been plugged, or blocked, reducing blood flow to the brain so that these beautiful neurons can't get their oxygen supply. They start to misfunction after just a few seconds, and the nervous system starts to fail.

The symptoms depend on where in the brain the trouble lies. If you were to have a drop in blood pressure to the left side of your brain, you would have right-sided weakness and something would go wrong with your speech. It would happen suddenly.

Blood flow might return, and you say, "Oh, that was nothing; it went away." Well, something caused it, and that "something" could come back. Our job is to make sure that something is taken care of.

Another kind of blood vessel disease is that a blood vessel ruptures, and blood goes into the brain - a hemorrhage. This is in many ways the opposite: One kind of stroke is caused by too little blood, and one kind of stroke is caused by too much blood.

Too little blood, we call "infarcts" - same term we use in the heart. Myocardial infarction means heart attack; this is cerebral infarction, brain attack.

If you put your hand right under the jaw, you'll feel a pulsation. That's the carotid artery; it divides in various branches. The big pipe, called the internal carotid artery, supplies most of the brain on the left side.

A blockage is "atherosclerosis," or hardening of the arteries, the predisposition for which is probably partly genetic and partly hypertension, partly your diet, a lot of different things, smoking cigarettes. It tends to happen in the internal carotid. This disease, carotid atherosclerosis, is the most common single cause of stroke.

If a (neurological) deficit goes away in less than 24 hours, we call that a "TIA," a transient ischemic attack. "Ischemia" means decreased blood flow; transient ischemic attack is a deficit gone in less than 24 hours. If it doesn't, the whole left side of the brain will die, with all of its functions along with it, control of the right side of the body, language, something worse than death.

Polls have been taken of elderly people, who are most at risk for this, and they are more afraid of dementia and stroke than they are of cancer. It's loss of mental function that frightens elderly people; they don't want this.

Another kind of vascular disease that might cause a stroke is called an embolism - a piece of clot that has come from somewhere far away, almost always from the heart.

The heart contains a lot of blood and, under certain circumstances, that blood can clot. If it clots and goes off to the brain, it'll get to a certain point and then stop. That's called a cerebral embolism, another cause of a stroke.

DR. WARACH: There used to be two major tenets of dogma: One, that when a stroke happened, the brain died, there wasn't anything you could do, and (the other) that brain damage is irreversible.

Our concepts have been changing. Permanent brain damage following a stroke is not immediate. It takes time for brain cells to die; it can take several hours and, in some cases, it can take several days.

One of the more amazing developments coming out of the laboratory in the last five or ten years is that brain damage due to stroke is, to some degree, reversible - if it's treated within hours. So every minute counts.

Two lines of research are nicely coming together to get at the question of "is it a stroke, or is it a TIA?" even before 24 hours. With recent innovations in MRI scans, we can actually take pictures in a split-second and not merely look at the structure of the brain but at the function of the brain, and decide what's damaged but not dead - and therefore, what might be potentially reversible and what might be at risk.

And a lot of the work coming out of the laboratory looking at the toxic effects of decreased blood flow to the brain has found, at least in laboratories, impressive results: Certain medicines, or drugs, can either prevent or, in some cases, actually reverse some of the damage due to stroke.

I think you can appreciate, this presents a window of opportunity to potentially intervene and treat patients with medicines. I want to emphasize that, right now, all these medicines and treatments are still experimental. They're only available in very tightly controlled research designs.

We've made a lot of progress on prevention. Even though stroke is still the third leading cause of death, it has been reduced slightly in frequency.

Internists, general practitioners, and family doctors in the community have managed to convince people that watching their blood pressure is important. Hypertension tends to cause the vascular diseases that cause stroke, so the first thing is risk factor reduction - get rid of cigarettes, deal with cholesterol problems, if possible, and treat hypertension.

We also have learned that taking one aspirin a day, and maybe even less, can reduce the risk of stroke in somebody who has already had a little strokelet, a little something. A large group of people have been tested, in multiple countries all over the world, and the results are much the same. Aspirin reduces the risk of stroke.

Initially, it looked like this was only effective in men, but the more recent studies show that it looks like it's effective in both men and women. And now we have other drugs that people can take, who can't take aspirin.

Another thing we can do - if somebody has a known heart disease that can generate a blood clot to the brain, an embolism - we can put people on a blood thinner. The one most commonly used is a drug called "warfarin" - rat poison, that's right. It turns out that if you give a very small amount of warfarin, it will thin out the blood enough to reduce the risk of stroke by 75 percent in people with certain kinds of heart diseases that generate emboli. That's pretty good.

We can open the carotid artery. Most carotid endarterectomies, as they're called, are not done as emergencies. They are routine operations - a little incision in the neck. The surgeons take that stuff out of the artery and close that artery back up. We now know from some large studies that, if the narrowing of the artery is greater than 60 percent, you're better off having a surgeon take the stuff out.

With regard to the treatment of stroke itself, we have to do two things simultaneously. We've got to open the pipes and protect the brain while we're doing it.

So, we're trying to open the blood vessels using drugs that dissolve the clot - that's called thrombolysis - and, at the same time, to give medications that protect the brain cells while we're trying to re-establish blood flow. One without the other isn't going to work.

So, my vision is, in the next, let's say, five years, we'll have stroke-mobiles going around Boston. You call 911. The stroke-mobile will come, lights flashing. Out will jump the EMT's; they will put an intravenous in and into the intravenous will go some kind of juice. That juice will contain cell protectors that will hold your brain intact while they rush you to the hospital. And somebody then puts a catheter up there, sticks up some thrombolytic drug and opens the pipe.

DR. SAMUELS: It's probably relatively rare as a cause of stroke in the population of people who have strokes - older people. In younger people, it's different. Some young people have spells that sound like strokes, and when we do all our tests, the blood vessels look pretty good. It may be what's called "vasospasm." Some people believe that's what happens in migraine attacks. There is some evidence that, during some migraine attacks, there's actually vasospasm, the brain malfunctions for twenty minutes, and then it comes back with a headache.

Q: If some strokes are hemorrhages, isn't it dangerous to take a drug like aspirin, which is essentially an anticoagulant?

DR. SAMUELS: Potentially, that's correct. But in the big studies in which aspirin was looked at, there wasn't an increased incidence of hemorrhages. So, it looks like aspirin protects against one kind of stroke and doesn't cause the other kind of stroke. Probably because it's such a mild medication.

Q: What about hormones and the probability of stroke?

DR. SAMUELS: Certain hormones - largely female hormones - can predispose to blood clotting. For example, the birth control pill has as one of its side effects thrombosis, or blood clotting. So, drugs of that kind could tend to increase blood coagulation slightly, but, in general, over thousands and thousands of people, it's very uncommon.

Q: When you get no blood flow to a certain site in the brain, how do you get the neuroprotective drugs into that area?

DR. WARACH: The ideal is you load up the blood with the neuroprotective drug and then you open up the blood vessel to dissolve the clot. In fact, these drugs work even if you don't do that. The decrease in blood flow is never 100 percent; alternate pathways in the brain can bring blood into an area. It's never quite enough; the patient still has symptoms from it. But over time, these alternate, or collateral, pathways get better. So, there is a way around the blockage to start to get the blood and, therefore, the drug into the area at risk.