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Episode 23 : Research from AHA 2007

Release Date: November 27, 2007

Dr. David Meyerson: Hi, I'm Dr. David Meyerson, cardiologist at Johns Hopkins, a member of the Scientific Advisory Board for the Vascular Disease Foundation and your host of this edition of Vascular Disease Foundation's HealthCast. We're very excited to be able to bring excellent, easy to understand science to you on all topics relating to heart and blood vessel diseases as a public service. As a public education forum, the Vascular Disease Foundation is made up of representatives of the premier medical and scientific advisory groups in the country that relate to vascular diseases. These are groups that use peer-reviewed science to verify that the information that you are getting is nationally recognized as the very best and most reliable data available.

We have a very special HealthCast today. The American Heart Association just completed their annual scientific meetings which were held in Orlando, Florida. This is a very highly credible forum where scientists throughout the world share the latest research on heart and blood vessel diseases and much of this impacts on peripheral arterial disease. So with me in studio to discuss perhaps six or seven of the new studies that we might want to be aware of and share with you today, is my friend and colleague Dr. Kerry Stewart. Dr. Stewart is Professor of Medicine and Director of Clinical and Research Exercise Physiology at Johns Hopkins, he is a member of the Vascular Disease Foundation's Board of Directors and he's also one of the responsible people whose brain child these wonderful HealthCasts were. Kerry, thanks so much for being here and we have some interesting things to talk about today, don't we?

Dr. Kerry Stewart: Absolutely, this was a really terrific meeting. There were about twenty-five thousand people. There were, I don't know how many thousands of presentations and we'll get through just a few of them, but there was tremendous science there.

Dr. David Meyerson: So again, this is open to the entire international community and it is really a very highly credible international forum for research on heart and blood vessel diseases.

Dr. Kerry Stewart: It's considered probably the number one scientific meeting in the whole field of cardiovascular disease.

Dr. David Meyerson: Well, we have spoken in the past on HealthCast and I would like to begin today about a study that was done about mortality. Why people with peripheral arterial disease seem to have both heart and blood vessel disease and die sooner than the rest of the population. We've said on this program before that even if you don't think you have heart disease, even if you've never had a heart attack or angina, even if you've never had blockages in the arteries that nourish the brain called the carotid arteries, but if you have developed a blockage in the arteries that nourish the legs, peripheral arterial disease, that means that you are more likely to have heart attack, stroke and die in the foreseeable future. Isn't that correct?

Dr. Kerry Stewart: That's correct and this particular study was actually a study that came out of Germany of nearly seven thousand patients who were sixty-five years or older who underwent a test called the ankle-brachial index or ABI. This is --

Dr. David Meyerson: Now we've talked about ankle-brachial index in this program and some people believe that it ought to be as prevalent a thing to do as just an ordinary electrocardiogram.

Dr. Kerry Stewart: That's right and as we --

Dr. David Meyerson: And let's just mention really quickly that's just the taking of the blood pressure in the arms and comparing it with the blood pressure in the legs.

Dr. Kerry Stewart: That's exactly right.

Dr. David Meyerson: It's something so simple, but it's just not done enough.

Dr. Kerry Stewart: Right. It's not done enough and in this particular study, at the baseline before the five years in which these patients were followed, about eighteen percent of them actually had a reduced ankle-brachial index. And what they found after five years was that twenty-four percent of those individuals with symptomatic PAD and nineteen percent with asymptomatic PAD were dead as compared to only nine percent of those who had a normal ABI. So after taking into account all the usual risk factors of smoking and high cholesterol and high blood pressure, PAD in fact, was associated with a forty percent increase in mortality.

Dr. David Meyerson: Kerry, this is striking information. This means that if we are doing ankle- brachial indices in a doctor's office on a regular basis, we can predict in a simple, painless, very low- cost way who needs aggressive care earlier.

Dr. Kerry Stewart: That's exactly right and this is what we have talked about on previous PodCasts, a relationship to the value of the ABI and clearly those individuals who identified to have PAD need very aggressive and comprehensive treatment of all their risk factors in order to prevent the condition that will lead to death which is some form of cardiovascular disease.

Dr. David Meyerson: Right. Now some people have a misconception that they think that something about the PAD then makes their heart sick, but what's happening is that the very same things that are capable of harming the blood vessels of the lower extremities which are larger vessels and often more difficult to damage than smaller more delicate ones, that same process is active and imagine if we, for almost no cost, minimal cost test, with no risk associated with the test and no pain associated with the test and it's non-invasive, no needles, no discomfort, no cutting, no nothing, you could find out that you were in this high risk group and then you turn around and begin to treat those things. We can really reduce the mortality of people and increase their functional capacity. Isn't that correct?

Dr. Kerry Stewart: That's exactly right.

Dr. David Meyerson: Well then Kerry, that's so important then -- and that's a study that was done in Germany and let's bring this back now to the United States. What about the prevalence of peripheral arterial disease in the United States? We have new data from the American Heart Association meetings on this too. Isn't that correct?

Dr. Kerry Stewart: That's right. There was a study in which a group of investigators out of Pennsylvania looked at data from the NHANES study, which stands for the National Health and Nutrition Examination Surveys, and they looked at the prevalence of PAD as, again using the ankle-brachial index, between the years of 1999 and 2004 and what they found was an increase from PAD prevalence from 1999 of three point seven percent of this particular population to four point six percent by the year 2004. This also went along with an increase again and many of the risk factors associated with PAD such as diabetes which increased in prevalence from seven point eight percent of the population and nine point five percent of the population. The rate of hypertension went from twenty- five percent of these individuals to nearly thirty percent of these individuals only five years later and unfortunately the rate of smoking which was at twenty- one point eight percent was essentially the same five years later at twenty-one point nine percent. But clearly we have an awful lot of work to do to get people to change their behaviors and get their risk factors under control to help reduce the risk not only of PAD, but again all the other vascular diseases that we've talked about.

Dr. David Meyerson: Terry, is there possibly some good news in this study that you just quoted? Is it possible that healthcare professionals across the spectrum of healthcare are now looking for this better? We're more attuned to calling it a major issue. For example, people with diabetes now, it's just not a risk factor for the development of coronary artery disease and other heart and blood vessel diseases, but it's almost a guarantee that once you have diabetes, you are soon to be going to develop coronary disease within a decade and are we then looking and educating our healthcare professionals and educating the public better? That's one of our goals.

Dr. Kerry Stewart: Well, it's really hard to tell from this study, in fact any study, whether or not the prevalence of PAD is due just because we know more about it, but if you look at the risk factors for PAD, they've actually seemed to have worsened, so there's some element of both. There's probably more diagnosis, but on the other hand, there's more of the risk factors and we've known about these risk factors for very long time, so there's nothing new about diagnosing diabetes or smoking.

Dr. David Meyerson: Obesity, hypertension, uncontrolled diabetes, these are critical things. Smoking, smoking must stop, must stop in our population. I know of nothing that I can do medically for people that will add more years to their life and reverse their tendency toward developing peripheral arterial disease and heart disease than smoking cessation, maintaining activity, a normal weight if you're diabetic, critically control your diabetes. These are absolutely critical things and this is preventable disease.

Kerry, let me tell you about one other study that was done. It looked at uncontrolled high blood pressure in women. They studied almost forty thousand female health professionals and what they found was that uncontrolled high blood pressure in women was a potent predictor of whom in the female population would develop peripheral arterial disease and they actually found that the systolic blood pressure, the top number, the higher number that we often talk about was more highly correlated than the systolic and diastolic blood pressures together, but it's just another point that all of these pieces fit together in a very beautiful machine of how disease is caused, how we can identify it and what we can do to prevent it. So again, for women who think that they are going to not develop heart and blood vessel disease and peripheral arterial disease quicker than the men in the -- more slowly rather than the men in the population, that used to be the case. Women are catching up in every phase of society. They are catching up in heart and blood vessel disease. Blood pressure control in women is very important to prevent peripheral arterial disease.

Dr. Kerry Stewart: That's exactly right.

Dr. David Meyerson: And there is another one which is very interesting which kind of dovetails with this study and that is another study about second-hand smoke exposure. Now, there's been a lot discussed in the media and in scientific community about are we making too much of second-hand smoke. Second-hand smoke, if you're a child around people who smoke, you get asthma much more quickly, you miss far more days of school. It's very bad developmentally for a child. It also is seen that in people who are around second-hand smoke they have an increased incidence of lung cancer and here's another study that shows that second-hand smoke is a major public health concern because it increases the risk of developing sustained systolic blood pressure in people who have been exposed in only a second-hand manner. We're not talking about smokers, we're talking about being near or around somebody that smokes habitually. So, these results provide further scientific evidence that involuntary, casual, not the primary smoker, but involuntary, casual, second-hand exposure constitutes a significant public health risk because it will push your blood pressure, your systolic blood pressure up and the study that we talked about just before this one said that people who have increased sustained systolic blood pressure have a higher incidence of peripheral arterial disease. So here are two studies that tell us that the blood pressure must be controlled and that smoking will increase the blood pressure, so I think we have two potent things. All of this dovetails, it is important information. I can't --

Dr. Kerry Stewart: I'm interested that you used the word second-hand smoke was an involuntary behavior, but I guess I would suggest that maybe it's not so involuntary because when you don't have to go to places where people smoke, if you can and two --

Dr. David Meyerson: If you want to stay married and your wife smokes, you might have to --

Dr. Kerry Stewart: Well, that's another issue, but this is even more of a reason to make sure that the family members, your family members and other people you affiliate with are not smokers because not only is it harmful to them, it's also harmful to you. So this is somewhat more of a motivation to get them to change their --

Dr. David Meyerson: This is a compelling addiction. The addiction to nicotine is truly compelling, there is no question about that and it is so worth being as supportive as you possibly can and internist and primary care docs now have greater mechanisms and better pharmacological assistance to help people who are serious about stopping smoking quit and I know of no behavior that will add more years to your life, to your functional capacity. Women usually stop smoking if I tell them, our patients that it causes dramatic premature aging. Most of us have some vanity, but it seems to carry today when you talk to our female patients about premature aging, but the fact of the matter is, it causes destruction of cells all over the body. If that's the only message you get from today's control your blood pressure, stop smoking and listen to Dr. Kerry Stewart, he'll tell you what's right.

Dr. Kerry Stewart: Well, we've been saying this message all along, but these new studies just reinforce that that message is at least based on our best knowledge to date, is the right message.

Dr. David Meyerson: Now Kerry, you're one of our national experts in exercise physiology and we spoke on HealthCasts previously about when you have heart disease and angina, it's an important thing. If you're getting chest pain when you exercise, you're not supposed to keep pushing. You're supposed to talk to your doctor, see the cardiologist, make sure we know what this chest pain, treat it appropriately and make sure that it is not a terrible warning for something worse. That's absolutely critical. But in claudication, in other words the leg pain that we get when we're exercising because there's too little blood supply to the lower extremities, that's not only a warning and requires the same work-up that we talked about previously, but in this situation, exercise actually improves your ability to do more exercise. Isn't that right?

Dr. Kerry Stewart: That's right and that's why the guidelines that we've recommended that people do, walking is the best possible exercise for improving the symptoms related to claudication or PAD.

Dr. David Meyerson: And there was something fascinating. We actually leaked this information on an early episode of HealthCast and -- cause it was just a couple kernels that were coming now, but they were very credible and that was, not only did exercise of the lower extremities make it possible for you to do more activity with your legs if you had claudication and peripheral arterial disease, but there was a suggestion that doing arm exercises could also possibly improve your ability to do leg exercises. As the kids would say, "What up with that?"

Dr. Kerry Stewart: Well, this new study that came out of the University of Minnesota, which in fact we did talk a little bit about earlier in the year, challenges this notion that walking is the only way to improve symptoms from claudication. And what they did was take a group of individuals, there were twenty-one men and seven females and they were age on average sixty-five which is about the age where the increase prevalence of PAD occurs, and they randomly assign them and this is very important, this was a randomized study so that subjects mainly by the flip of a coin were asked to undergo a typical treadmill workout or just a workout just with their upper arms, which has not been the standard guideline for improving claudication symptoms and what they found was, was that the benefits that occurred arm ergometry or arm exercise, was nearly equivalent to that of treadmill training, so these individuals were able to get the benefits of exercise without suffering from the claudication pain that would occur from walking on the treadmill.

Dr. David Meyerson: So is the body creating some sort of substance that dilates blood vessels, is it creating some sort of substance that allows blood flow or muscles to metabolize at a different rate so that they can do more activity, or is it just the overall physical training that no matter how you get it, is beneficial?

Dr. Kerry Stewart: Well, we're not exactly clear what the mechanisms are. It was believed that this local benefit of exercise, in other words by walking and using the legs, you'd get a local affect, a local benefit and it was believed that an improvement in the muscle's ability to use oxygen was one of the primary reasons why people got better, but this study would suggest exactly what you said, is that there's more of a generalized or a systemic effect of exercise that will filter down to the legs even if you're not using them during the workout.

Dr. David Meyerson: So again, if you want to be active when you're eighty, you've got to be active when you're seventy, you've got to be active when you're sixty, and fifty. Activity begets activity, the more you do, the more you're going to be able to do, the better your cardiovascular fitness is going to be overall and that's something that rings true for everything in your research area, doesn't it Kerry?

Dr. Kerry Stewart: Absolutely. If medicine was -- if exercise was a medicine, it would be one of the most widely prescribed pills that you can offer anyone.

Dr. David Meyerson: Right after aspirin.

Dr. Kerry Stewart: Right after aspirin. Well, maybe along with aspirin.

Dr. David Meyerson: Because everybody benefits from activity, don't they?

Dr. Kerry Stewart: There's almost nobody that would not benefit -- that's a triple negative I think I just --

Dr. David Meyerson: That's okay, but I think we know what you mean.

Dr. Kerry Stewart: You know what I meant. Everyone will benefit from exercise.

Dr. David Meyerson: Wonderful. Are there any other -- I think we're coming up on our time limit here, but is there anything else that you want to share with our listeners from the new American Heart Association meetings scientific sessions?

Dr. Kerry Stewart: Well, there are probably about ten thousand studies to choose from, but I'll just --

Dr. David Meyerson: I don't think we have time for most of those.

Dr. Kerry Stewart: We don't have time for those, but there was one that I think I'd like to discuss -- I would like to discuss which points to the powerful risk of obesity particularly if the fat is around the waist. That's a powerful predictor of a condition known as the metabolic syndrome. Metabolic syndrome is a collection of the risk factors, cholesterol, hypertension, diabetes or glucose intolerance --

Dr. David Meyerson: And the central obesity that we're talking about.

Dr. Kerry Stewart: -- and central obesity. And to the extent that people are overweight, particularly if that weight is around their waist, they are identified as having the syndrome known as metabolic syndrome and people with metabolic syndrome are at a very, very high risk for developing diabetes and developing heart disease. And what this study showed was exactly that. That if your fat is more around your waist than anywhere else, you are at high risk for this metabolic condition.

Dr. David Meyerson: Now that's going to lead to probably a topic for another program, but how do you get the weight to preferentially fall away from that central adiposity that we talk about which causes, as you said glucose intolerance, a diabetic profile. It often is associated with high triglycerides, high LDL or bad cholesterol. It can be associated with low HDL or good cholesterol. It is associated with high blood pressure and it's associated with impaired physical function and a very, very high risk of premature heart and blood vessel and peripheral vascular disease so that if you think that anyone in our listening audience, if you think this is beginning to sound like you, part of what we are all about here at Vascular Disease Foundation and HealthCast is to give you enough information to say, this is now the time for me to act. This is the time for me to see my physician. This is the time for me to know what my blood pressure is, to stop smoking, to make certain that I'm not diabetic, to normalize my weight, to do activity. What am I leaving out Kerry?

Dr. Kerry Stewart: Well, let me answer what started out as a question I think was how do you reduce abdominal obesity and one is first of all reduce overall obesity by restricting calories, so losing weight is one way, but what has been shown, not from this study that we talked about, but other studies and including work that I've done is that exercise, in fact, seems to have a preferential effect on abdominal fat. In other words, people who exercise will lose abdominal fat more quickly than if they didn't exercise. That's a very important benefit of exercise that is just starting to become well known.

Dr. David Meyerson: Now I promise this question is going to be a topic of a future discussion, but what do you think about carbohydrates as they control central obesity?

Dr. Kerry Stewart: Well, there's a growing body of information suggesting that carbohydrates is at the root cause of diabetes and heart disease and one of the, one of the reasons why is that carbohydrates, the way they get used by the body if they're taken in, in excess ends up as the fat that ends up around your waist. So carbohydrates appear to have a direct effect on the risk of developing diabetes and heart disease.

Dr. David Meyerson: So let's plan to do a program about weight management and exercise as it impacts on metabolic syndrome and the development of peripheral vascular and other vascular diseases as one of our future topics.

Dr. Kerry Stewart: I think that will be a great topic.

Dr. David Meyerson: Wonderful. You've been listening to HealthCast. You've been listening to Dr. Kerry Stewart, he's Professor of Medicine, Director of Clinical and Research Exercise Physiology at Johns Hopkins, he's a member of the Vascular Disease Foundation's Board of Directors. We've been talking about some interesting new studies that came out at the American Heart Association Scientific Sessions that were held in Orlando, Florida just a few weeks ago. Again, a very highly credible forum for international sharing of the latest research on heart and blood vessel disease and many of which impacts directly on peripheral arterial disease. Thank you so much for listening for Vascular Disease Foundation, from my colleague Dr. Kerry Stewart, I'm Dr. David Meyerson, have a good day.

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