TOPICS > Health

Stroke Drug

December 14, 1995 at 12:00 AM EDT


CHARLAYNE HUNTER-GAULT: A study in today’s “New England Journal of Medicine” holds out the promise of near or complete recovery for some victims of stroke. Researchers say the drug TPA is the first early treatment that can be offered to prevent irreversible brain damage, but there are also risks. Doctor, thank you for joining us. Tell me, in the simplest terms, what this study came out with and the significance of it.

DR. MICHAEL WALKER: Well, Charlayne, stroke is the third leading cause of death and the prime cause of disability in this country. About a hundred and fifty thousand patients die each year, but of the five hundred thousand who have strokes, the vast majority, as you know, don’t die, and they are left disabled. And after this drug comes in–and that’s the important part of this treatment–basically what the study showed is that if you look at the patients who didn’t receive TPA, only about 20 percent had a complete or near complete recovery, whereas, those who did receive the drug, 31 percent had a complete or near complete recovery. There was no change in death.

CHARLAYNE HUNTER-GAULT: And up to this point, strokes have been untreatable altogether, right?

DR. WALKER: Well, that’s a major problem. One of the general beliefs is there is nothing that you can do for stroke, and, thus, patients don’t come into hospitals on time, and physicians aren’t sure exactly what they can do.

CHARLAYNE HUNTER-GAULT: All right. Now, tell me what TPA is exactly.

DR. WALKER: TPA, Tissue Plasminogen Activator, is a drug which essentially dissolves the blood clots. We believe that a large number of these non-fatal and fatal strokes are caused by blood clots which go into the brain, clog the arteries, and prevent the delivery of glucose and oxygen to brain cells.

CHARLAYNE HUNTER-GAULT: And what precipitates that? Do we know?

DR. WALKER: There are a wide variety of reasons: Cardiac disease, atherosclerosis. There are many, many causes, many of which we really don’t know yet.

CHARLAYNE HUNTER-GAULT: And how exactly does the TPA work to limit the damage, or to keep it from having any–does it just limit the damage, or keep it from having any effect at all?

DR. WALKER: No. This study was conducted to very high standards. It required complete recovery or near complete recovery for these patients with stroke. The way it works is by dissolving that blood clot, and you must do this within a very quick period of time. The time limit set for this study was three hours, i.e., within three hours, the patient must be in the hospital, have a CAT scan, which demonstrates that there is no bleeding in the brain, because that could be dangerous, and the patient’s started on treatment.

CHARLAYNE HUNTER-GAULT: So this is–I mean, there was a study done back in the 50’s, when doctors tried to dissolve brain clots but they gave that up. The difference here is the time element?

DR. WALKER: The difference here is two things: The time element, and they had a tremendous number of hemorrhages which caused them to stop those studies early. This study had a very limited hemorrhage rate, which was kept under control, and in spite of those hemorrhages, the efficacy of TPA was demonstrated.

CHARLAYNE HUNTER-GAULT: Okay. Now, not all strokes are caused by blood clots, though. I mean, aren’t some caused by hemorrhaging or some other factors?


CHARLAYNE HUNTER-GAULT: Does this work for those too?

DR. WALKER: No. Not only doesn’t it work but those are the very precise patients who should not receive TPA. And so it becomes really quite critical that a CAT scan be obtained before treatment is started, that that CAT scan is read by experts who are fully knowledgeable of neurologic and stroke disease so that they really can help on this.

CHARLAYNE HUNTER-GAULT: Okay. Now there are risks with the TPA. Tell me about those and how significant the risks are.

DR. WALKER: TPA, like almost any drug that is effective, has a down side, and the down side is it too can cause bleeding. One can limit that bleeding by treating the patient early. That’s why there is a three-hour time limit on this. The later you wait to start treatment, the greater the chance of having a hemorrhage into the brain, which, of course, can be devastating to patients.

CHARLAYNE HUNTER-GAULT: But strokes are quiet things, aren’t they? I mean, how do you know you’re having a stroke? How quickly can you get to the hospital? I mean–

DR. WALKER: That’s part of what we’re going to have to do in a rather massive campaign, I think, in terms of trying to teach people the problems related to stroke. You’re absolutely right. Stroke is painless compared to heart disease, where you have a crushing pain in your chest, but if patients and their relatives become aware that stroke can be treated, that the clock is running from the moment of the first symptom, and that they are going to have to really with great speed get that patient under medical supervision, then I think things can be done. It’s going to be a slow process.

CHARLAYNE HUNTER-GAULT: Now, this risk that you talk about, which is not insubstantial, is that right?


CHARLAYNE HUNTER-GAULT: How are doctors going to receive this information now? Are they going to be at all apprehensive about using the drug?

DR. WALKER: I think doctors should be apprehensive about using the drug. I think they need to look at and study this article very, very carefully to see the precise parameters under which the study was conducted. When they do that, I think they will start to get themselves convinced that this is good treatment but it must be carried out precisely as set.

CHARLAYNE HUNTER-GAULT: Now, the FDA hasn’t approved it yet. How soon do you think this treatment will be available?

DR. WALKER: Well, the treatment is available now in that TPA is utilized for heart disease. But it is not labeled for the use in stroke, and that’s going to take, I think, a period of time longer before that occurs.

CHARLAYNE HUNTER-GAULT: All right. Well, Dr. Walker, thank you for joining us.

DR. WALKER: My pleasure.