a special program of the National Emergency Medicine Association (NEMA)

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Week: 600.6 

Guest: Dr. Woosley, Georgetown  

Topic: Aspirin and preventing heart attacks and strokes 

Host/Producer: Steve Girard 

NEMA: Just who should take aspirin to prevent heart attacks and strokes? Some people say everyone....and that’s wrong. But the American Heart Association has just announced its new recommendation on aspirin for prevention...indicating that those who have been diagnosed with heart disease...in high risk groups...should take aspirin to prevent a first heart attack...and if those who have had heart attacks or strokes should take an aspirin immediately if they believe they’re experiencing a new attack. Today we’re with Dr. Raymond Woosley, Professor and Chairman of the Department of Pharmacology at Georgetown University Medical School in Washington, D.C. 

WOOSLEY: Aspirin is one of the oldest, if not the oldest drug we have around. People were using willow bark and willow for fever and pain as herbal remedies centuries ago. It was only in the 50’s and 60’s that we recognized that high doses of aspirin could cause bleeding, and could cause ulcers to activate serious bleeding problems, and then people began to recognize that heart attacks and strokes were caused by blood clots. So, researchers started looking at the effects of aspirin on blood clotting, and found that very low doses of aspirin actually could block the ability of a person’s blood to form clots. The beginning of a clot is caused by tiny little cells or elements in the blood called platelets, that stick together. So, when you cut yourself, for example, the platelets gather at that point and they stick together and they plug up the cut. Well, they also will form at irregular surfaces in the blood vessels. So, if you’ve got a blood vessel in the heart...it’s carrying blood to feed your heart...and it has a rough area...platelets can stick to that and cause a blockage and heart attack. The aspirin can, in low doses, can prevent the platelets from sticking together, and therefore you can prevent the clots that cause heart attacks and that’s the basis for the use of aspirin to prevent heart attacks and strokes.  

NEMA: What is it in aspirin that causes the platelets not to stick together? 

WOOSLEY: The chemical name for aspirin is acetyl salicylic acid, and the salicylic acid is the part that lowers the fever and corrects the pain....but the acetyl part, the acetyl of aspirin is transferred to the platelets, and the platelets are actually acetylated. The acetyl group hooks up on the platelet and prevents it from sticking to other platelets.   

NEMA: Several years ago, it was recommended that folks who have had a heart attack or stroke take a daily dose of aspirin. How has that advice changed over time? 

WOOSLEY: The dosage has changed. The early studies observed that those taking high doses of aspirin had lower risk of heart attack, and they started looking at lower doses, and one aspirin twice a day...then one aspirin, once a day. And one aspirin is 365 milligrams, or 5 grains. And then people began to recognize that that was even too much, and that you might be able to use a lower dose to block your platelets from sticking together. And finally, people agreed that one baby aspirin per day, which is about 81 milligrams, would be enough if you take it regularly, to prevent your platelets from sticking. And the advantage there is that you don’t have as many bleeding problems. You’re just blocking the platelets from being sticky, but they can still shut off bleeding. So you’ve just reduced their ability to stick together, not totally prevented it. And so, the recommended dose now for preventing heart attacks and strokes is one baby aspirin per day, or maybe one half of an aspirin per day. There’s some discussion still about whether for prevention of stroke, you might need higher than one baby aspirin. But one baby aspirin a day is the recommendation for preventing heart attacks, and one aspirin a day...five grain aspirin...is the dose for preventing strokes.  

NEMA: The FDA recommendations differ from the American Heart Association recommendations in that the AHA promotes daily aspirin therapy to those diagnosed with heart disease...in the risk group for heart attack...not just to those who have survived one.... 

WOOSLEY: FDA is bound by law to make recommendations based on data that has been presented to them, and their advisory committees are looking at the data that are available on this issue...and there was an advisory committee looking at this not too long ago. The American Heart Association is not limited by law, and has looked at that data and recommended that ...or acknowledged that there are a lot of people who have heart attacks and strokes and the first symptom of a heart attack or stroke could be death. So, we recognize...we don’t want everybody, we don’t want to put aspirin in the drinking water, but we also want to identify people who are at high risk of heart attack and suggest that they take aspirin to prevent a first heart attack. Recognizing that all drugs have side effects, and there will be some downside for it. But if we select those people at very high risk...that would be someone who’s got a very strong family history, someone with hypertension, someone with very elevated cholesterol, smokers...especially smokers...those are the people who are at very high risk of heart attack, and the American Heart Association feels that the data are strong enough at this point to recommend that those people take one baby aspirin a day. 

NEMA: I know there’s no data right now that indicates that healthy people...those not in the high risk groups...should take aspirin as some sort of prevention therapy. But I have people tell me I should be taking it...so it seems that people are taking the aspirin advice seriously...but perhaps overreacting a bit...? 

WOOSLEY: Well I think that is the concern that the FDA and The American Heart has also...that people might take it who are really not at risk for a heart attack, and there is harm. There is a small, but significant increase in bleeding caused by taking aspirin. And we believe the harm is smaller than the benefit in preventing heart attacks if you’re at high risk, but if you take a very low risk person who’s not likely to have a heart attack, and you give them aspirin...the only thing you’re going to see in the population is an increased risk of bleeding problems. 

NEMA: And of course, it’s not a substitute for getting up and exercising, and being on a healthy lifestyle course.... 

WOOSLEY: That’s a very important point. That people might think aspirin and think, Well I can go ahead and smoke, or I can go ahead and fail to exercise and do all the other things. And that’s a very important message: that aspirin...even when it’s recommended....is only part of a healthy lifestyle, and the most important thing that everyone can do is to look at their risk factors. And the most important risk factor of all is smoking. Many people recognize that, "...sure, cigarettes cause cancer...", but what they fail to realize is that cigarettes are a major cause for heart attacks - the most important risk factor for causing heart attack and stroke. And they think, "well, it hurts my lungs, but it doesn’t do anything else. But that’s not the truth. The truth is that the major concern is what is does to your heart.  

NEMA: And I guess another good step would be to clear with your doctor any decision to take aspirin on a daily basis? 

WOOSLEY: That’s right. People who are thinking about taking aspirin for preventing heart attacks and strokes, check with your doctor...and make sure they know what other medications they are on, because there are some interactions between aspirin and other medicines that you need to be aware of. They need to know what the symptoms would be if they were to develop a bleeding problem, so that they could call their physician immediately if they had some evidence of a bleed from their aspirin. And the third consideration is that there are some people who are allergic to aspirin. It’s not common, but allergic reaction to aspirin can be anaphalaxis or near death...or death. It’s not common, but it’s a serious reaction....and it’s important that your physician know that you have just decided to start taking aspirin.  

NEMA: What about the recent recommendation that people who have had a heart attack or stroke take a full aspirin if they feel a new attack is occurring? 

WOOSLEY: It is a good recommendation. I think control trials have compared blood thinners, including aspirin, and found that a single 5 grain aspirin, taken as early as possible with a heart attack...gives you the very best outcome, compared to other forms of blood thinners. Now, my own recommendation is that they immediately go to an emergency room or a physician, where that can be done under controlled observation. I think if a patient thinks they’re having a heart attack, and for some reason they can’t get to the doctor immediately, they might want to go ahead and take an aspirin. But my recommendation is that they get to the hospital, take an aspirin with them, and ask the doctor, "should I go ahead and take this".  

NEMA: Dr. Raymond Woosley, Chairman of the department of pharmacology at Georgetown University Medical School in Washington. Remember, only those who have been diagnosed with heart disease or designated high risk should be taking aspirin to prevent a first heart attack...and the American Heart Association has recommended heart attack survivors should take a whole aspirin if they feel they’re having a new attack. You should check with your doctor before you put yourself on aspirin, to make sure it’s okay, and to confirm a dosage. 

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NEMA: Thanks for joining us for today’s program. If you have any comments or suggestions, contact this station. Or visit our home page at: www.nemahealth.org/...for a look at transcripts of this or past programs, or to find out more about the National Emergency Medicine Association. I’m Steve Girard at The Heart of the Matter.




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