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Episode 24 :Back to Basics:  Ischemia

Release Date: April 16, 2008

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 for this edition of Vascular Disease Foundation's HealthCast.

We're very excited to bring you excellent, easy to understand science on all topics relating to heart and blood vessel diseases as a public service. You may recall that the Vascular Disease Foundation is a non-profit, education organization dedicated to reducing the widespread prevalence and effects of vascular diseases by increasing public awareness of the benefits of prevention, diagnosis, management and rehabilitation. We're continually developing educational information and other resources about vascular diseases for medical professionals, the public and especially for those affected by common vascular disorders.

As a public education forum, the Vascular Disease Foundation is made up of representatives of the premier medical and science 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're here in studio with my good friend and colleague Dr. Kerry Stewart.  He's Director of Clinical and Research Exercise Physiology at Johns Hopkins.  He has just finished his six-year term on the Board of Directors of the Vascular Disease Foundation and now he sits on the Scientific Advisory Board. Dr. Stewart, Kerry my good friend, welcome back to our series and today I'm very excited because we're going to get back to basics.

Dr. Kerry Stewart: Yeah, we're going to be discussing an extremely important topic.  It kind of underlies many of the problems that we've talked about in the past and many of the problems that our listeners are affected by.

Dr. David Meyerson: We're going to be talking about a word ischemia, I-S-C-H-E-M-I-A.  It's pronounced ischemia and it generally means lack of blood supply, but one of the exciting things about ischemia is depending upon where it happens in the body, it has a different name, it's got different affects and it's got different therapies, so we're going to be talking about what is ischemia, where does it occur, what are the symptoms of ischemia, how is ischemia diagnosed, what are the risk factors for ischemia, how is ischemia treated and what can you do to prevent ischemia. That's a lot of ischemia there, isn't it?

Dr. Kerry Stewart: You've got it.  Well, there's a lot of it out there and as you know, one of our main missions here, I think you already stated that, was to get people to follow those lifestyle behaviors like not smoking and exercise and things we'll talk about to prevent it in the first place because that's the best thing.

Dr. David Meyerson: Just so everybody knows where my heart is, no pun intended, as a cardiologist, but could you say stop smoking three times?

Dr. Kerry Stewart: Stop smoking three times.

Dr. David Meyerson: Perfect. In any event, ischemia.  We have such a good time doing this program and we're going to leave this in because people are going to know we're having such a good time. So ischemia is a lack of blood supply, oxygen and nutrients to any part of the body.  You can have ischemia occurring in the brain.  When we have ischemia occurring in the brain and it's temporary, we call it a transient ischemic attack.  That's like if you face goes numb for a short few, for a few minutes, if your hand gets clumsy, if the side of your body doesn't work for a period of time and then comes back; that's a temporary thing.  We call that a threatened stroke or a transient ischemic attack. So when ischemia happens in the brain, it causes dysfunction, it causes our inability to either balance or to speak or to understand or possibly to see or control our motor function of our body and when it's permanent, when ischemia goes on and it's not temporary, when it's permanent, ischemia in the brain is called a stroke.  And we all know that stroke causes, it is one of the most disabling diseases that we have and we want to prevent, we want to be able to predict and prevent transient ischemic attacks and especially prevent strokes.

So that's where -- Kerry, what about lower extremities?  You're an expert in exercise physiology and you're always worried in your clinical practice and your research evaluations about blood supply to the legs.

Dr. Kerry Stewart: So ischemia, when it occurs in the lower body, typically the arteries that feed the legs, that condition is known as peripheral arterial disease.  It's the same process that you just spoke about; blockages causing limited blood flow. Some people will get symptoms.  When you get symptoms, that condition is known as claudication and when the ischemia gets very severe, when the blockages get very severe and blood flow is either very restricted or cut off entirely, that can lead to critical limb ischemia and that often leads to amputation because there's no way for the tissue to recover.

Dr. David Meyerson: So what happens is, when ischemia is not so bad and you're walking up a hill to get the mail if your mailbox is down the road or if your in a rural setting or if your in your apartment, a city dweller climbing up two or three flights of steps, by the time you get to the second flight, all of a sudden your calf is grabbing you or your thigh is grabbing you and you feel like a pair of pliers squeezing or some burning pain and you have to stop. That could mean that the muscle in the leg is not getting enough blood supply oxygen and nutrients. Right?

Dr. Kerry Stewart: That's exactly right, but unfortunately only about thirty to forty percent of people with lower leg ischemia actually get symptoms, so there's an awful lot of people out there who have this condition, but really don't know about it.

Dr. David Meyerson: And part of what we'll talk about in just a few minutes is how to recognize if you have ischemia to the lower extremities without symptoms and that's a very important thing to find out.

Dr. Kerry Stewart: Absolutely.

Dr. David Meyerson: So ischemia can then occur in the, we talked about the head and we talked about transient ischemic attacks and strokes. We talked about claudication which is temporary.  The pain comes when you exercise, it goes away when you rest and it can also be treated, but it's an important red flag to anybody listening.  If you have these symptoms, tell your doctor. And finally if the ischemia becomes more permanent, an area of the leg gets permanently deprived of blood flow and you can have pain at rest or you can have ulcers or wounds that won't heal and you can even have gangrene.  And these are again, critical features of disease which must be treated.

Now let's go up to the heart for a moment. Everybody knows that if you have, we've seen on television people clutch their chest, they're having chest pain, they're having something called angina or some people call it angina.  Both pronunciations are fine.  The cardiologists, most of us call it angina and what happens is that that is a temporary lack of blood supply and nutrients to the heart muscle with exercise generally.  Sometimes it can come on at rest and it's even a bigger warning if it comes on at rest because it means you don't have so much functional reserve, but if it's happening when you're doing exercise, it means that there may be a blockage in an artery that nourishes the heart muscle and the demand for oxygen and for nutrients and for blood flow when you do activity is outstripped by the inability of a narrow vessel to supply it and that's the temporary thing.  It comes on when you exercise and goes away with rest. That's angina.

If we take that the rest of the way and then block that artery off entirely, that's when you have a heart attack.  Heart attacks come in all shapes and sizes from a little tiny few nests of cells that we can only measure in a blood test to a major -- remember when Fred Sanford puts his hand over his --

Dr. Kerry Stewart: Right.

Dr. David Meyerson: -- and looks to the sky and says, "Elizabeth, it's the big one."

Dr. Kerry Stewart: It's the big one, here I come.

Dr. David Meyerson: So everything between those are all possible and they're all warning signs.

Dr. Kerry Stewart: Let me just say something about the big one because in fact in about twenty to twenty-five percent of cases, there really are no warning signs.  The big one does come and the individual actually can have sudden death.  And if they're not dealt with immediately by emergency medical care, they will die. So it's critically important -- we'll talk about this a little later, to focus on those risk factors, those conditions that put someone at a high risk of developing heart attack or any of these conditions.

Dr. David Meyerson: And then finally there is another less commonly talked about, but what we call mesenteric or gut ischemia.  And that is that the intestines require a very rich blood supply and in order to help our digestion and etcetera and there can even be ischemia there. So depending upon where it happens in the body, we have different names for it, but one of the things that the Vascular Disease Foundation is all about Kerry, is preventing disability and maximizing function and each of these areas that we talked about, have warnings and then they have a permanence to them when it gets more extreme and what we are all about is making certain that people who have symptoms don't ignore them so they get evaluated because this is preventable disease and we're also about preventing the disease from ever starting.

And so there are methodologies for us to predict who is more likely to get disease, what risk factors need to be dealt with, so we're all about prevention and prolongation of life and high levels of function. So what are the symptoms of ischemia?  Kerry, I think we already covered that in part.

Dr. Kerry Stewart: Well, we covered many of them and we can just go over some of them again because again, as you said, they're so important. So the most common symptom in the lower leg is claudication.  This is the pain again that occurs with walking, goes away with rest and indicates peripheral arterial disease.

In more severe cases, it will occur at rest or while asleep, it will wake you up and when it's even more severe, people will feel cold limbs, loss of hair, development of ulcers and their toes, in fact, may turn blue.

Dr. David Meyerson: And that's a medical emergency, of course.

Dr. Kerry Stewart: That's a medical emergency.

Dr. David Meyerson: If you have, if your leg turns cold or it's painful sitting there at rest or it's looking blue, etcetera, that is truthfully a medical emergency. And but let's get back to why it's so important to ask for help and that's, with a lower, with claudication; it's a warning that the blood vessels of the leg are compromised, okay?  But remind our audience what we now know when people have lower extremity ischemia, it's a warning that if you can make a blood vessel in the leg begin to be compromised, then there's been enough disease active that other areas of the body could also be compromises.

Dr. Kerry Stewart: Well, when someone's first diagnosed with peripheral arterial disease and has the symptoms; it's a process that's gone on for a very long time and it's a process that will continue to go on and progress over a very long time.  But the more immediate problem is the fact that this is a marker for atherosclerosis, which is the process that causes ischemia or blockages somewhere else throughout the whole body.

Dr. David Meyerson: Remember our sixty year old house, if the plumber tells you there is a blockage in a pipe in the second floor and all the plumbing in the house is the same age, it shouldn't shock you for a minute that there's some problems with the plumbing in the basement.

Dr. Kerry Stewart: That's exactly right and this is our twenty-fourth episode and this house is still standing, but the way we describe it, it sounds like it might collapse any minute, but I think it is a great analogy.

Dr. David Meyerson: We want this house to live to be a hundred.

Dr. Kerry Stewart: We want this house to be a hundred before it falls down.

Dr. David Meyerson: You know what Eubie Blake said on his one hundredth birthday?  He said, "If I knew I was going to live this long, I'd have taken better care of myself."

Dr. Kerry Stewart: I would have taken better care of myself.  Right.

Dr. David Meyerson: Absolutely.

Dr. Kerry Stewart: Well, that's what we hope to do here. So when the plumbing is bad in the legs, it's a warning that there is going to be a problem somewhere else.

Dr. David Meyerson: Now remember these are some of the larger blood vessels in the body.

Dr. Kerry Stewart: Absolutely.

Dr. David Meyerson: So if we know that vascular disease continues over time, if you can harm a large blood vessel enough to compromise its flow, it must be easier to harm a smaller blood vessel, i.e. those that are in the neck, the carotid arteries that nourish the brain.

Dr. Kerry Stewart: Or the coronaries that affect the heart.

Dr. David Meyerson: The coronary arteries that nourish the heart muscle.  Or the mesenteric arteries and sometimes it even happens to the kidney arteries and it's another cause of high blood pressure, interestingly enough.

Dr. Kerry Stewart: That's exactly right.  And what we know from extensive research now is that when someone gets the diagnosis of PAD, over the next five years, they'll likely have either a heart attack or actually die of a heart attack or stroke.

Dr. David Meyerson: And so it's not that -- people used to think that you have peripheral vascular disease and it causes some other risk factor, but it is such an important red flag marker to say look elsewhere.  It's up to you and your doctor, if you have this and the doctor begins to treat it.  Let's say the doctor sends you to a -- well, let me back up.

Dr. Kerry Stewart: Back up.

Dr. David Meyerson: What's the easiest way to diagnose lower extremity ischemia?

Dr. Kerry Stewart: Well, there's a very simple test called the ABI or the ankle brachial index which is simply a measure or a ratio of the blood pressure in the arms versus the blood pressure in the legs.

Dr. David Meyerson: So the doctor puts a blood pressure cuff on both just like we take blood pressure?

Dr. Kerry Stewart: Exactly and if the blood pressures are equal, the ratio is one, you're okay.  If it's less than one, meaning that the blood pressure in the leg is less than the arm, that's not okay and it's a simple diagnostic way of determining whether or not somebody has peripheral arterial disease, even if they don't have symptoms.

Dr. David Meyerson: That's what we call a

screening test.

Dr. Kerry Stewart: That's a screening test.

Dr. David Meyerson: And a screening test is enough to tell you should you be looked at further and how so.  And there are other studies that can then be done after that which might include for example, doppler studies or sound wave studies of the legs which actually do look at the blood flow, just like the policeman can tell us how fast we're going --

Dr. Kerry Stewart: Sure.

Dr. David Meyerson: -- by shooting a laser gun at the car and with the frequency change of the signal that bounces back, the little gun calculates how fast we're going.

Dr. Kerry Stewart: Yeah and I don't remember which episode number it was, but several months ago we had Dr. Elizabeth Ratchford who is a specialist on diagnosing vascular disease and she talked extensively about some of these tests so I refer you back to the episode 21 on diagnosing vascular disease.

Dr. David Meyerson: Certainly.  So once you find out that you have some degree of vascular disease, then we get into all types of prevention and the doctor will be then looking at your blood pressure and your cholesterol and smoking cessation. And Kerry let me just remind our audience that smoking causes spasm of the arteries throughout the body.  It causes the blood to be more coagulable, more likely to clot.  It facilitates the laying down of plaque and other vascular diseases and it causes the inner lining of the blood vessels, called the endothelium, to start to malfunction.  And all of those together make the blood supply less and less and less.

And by the way, this is very important to many of our men in the audience because the vascular disease and diabetes, which we also have to mention, can also affect sexual function and it's a very important -- it's, this is normal behavior, people who are normal and want to remain so in this domain really should listen up and be very careful about this because the very same things that we do to prevent claudication from getting worse, to prevent angina from getting worse, to prevent TIA's from becoming strokes, etcetera, etcetera also all of those measures are improve blood supply to the abdomen and lower than that and enhance sexual function.  So that is, for someone who wants to maintain their health in that domain, and for some people that's the only thing that's going to get them into the doctor if that's not working.

Dr. Kerry Stewart: Well, whatever it takes. But I think you're exactly right because by managing what we call the risk factors, we're really attacking the underlying process for all these conditions that we talked about. So the risk factors for peripheral arterial disease, the risk factor for heart attack, the risk factors for stroke are nearly the same.  So by treating the risk factors for one, you're, in fact, treating the risk factors for all of them.

Dr. David Meyerson: Absolutely.  And now if you have had a heart attack or a threatened heart attack or angina or a bypass procedure or an angioplasty, if you've had a transient ischemic attack, if you've had a stroke, hopefully it's small, hopefully you've recovered from it, but you still then want to make sure that the doctor is not only treating all of the risk factors that we talked about, but then you also want the doctor to be looking for peripheral vascular disease. And the converse is especially true.  If you have peripheral vascular disease and it's being looked at, you want to talk to your internist and make sure that they have then screened you for blood vessel problems in the abdomen which would be a sound wave test looking at the abdominal aorta.  You'd want them to look at the carotid arteries, the vessels that nourish the brain and it might be also quite reasonable to consider a cardiac stress test with an imaging modality meaning either a stress test with an echocardiogram attached to it or a stress test and nuclear imaging attached to it.

When you go, when the doctor looks more for peripheral vascular disease, there are magnetic resonance special scans that can be done that show how narrow the blood vessels are and of course, there are angiograms that can also be done, which are you put a little tiny needle in a blood vessel and inject dye which shows up on X-rays and this also can tell exactly where problems are.

But again, if you are smart enough, if you sense that you have a plumbing problem anywhere in the house then you want to be looking at all, and the houses are our beloved human house, or the body that carries us from the beginning to the end and our precious vehicle that makes our life able so that it wouldn't have to depend upon others and we can be helpful to others.  If you want that body to last, let's make sure that we look at all these things together and now you know that ischemia in one area of the body has one set of consequences.  It has a different set of consequences in the other, but it's all the similar mechanism.

Dr. Kerry Stewart: It's exactly, that's exactly right and I think it's important that we also take a minute to talk about some of the treatments that are being done in large numbers now.  Specifically either surgery or angioplasties where stints are put in and segments of arteries are being opened up.  Now that's often very helpful.  It fixes the artery, it reestablishes blood flow, but it doesn't really fix the underlying problem.  Because the underlying problem is a process that exists through the entire body.

Dr. David Meyerson: So you're saying that once the stent -- a stent looks like maybe the spring inside a ballpoint pen -- if you put it in a heart artery, but if you put it in the leg, it looks, it's a little bit larger.  It's a little mesh work grill.

 Dr. Kerry Stewart:Yeah, I mean it works fine, but the problem is just by fixing a couple of millimeters of an artery, doesn't reduce the risk of having problems again in other areas, because the underlying problem needs to be attacked. So even if someone does get a procedure and they feel better, the problem is not over.

Dr. David Meyerson: This is true of whether you've had a bypass surgery --

Dr. Kerry Stewart: Absolutely.

Dr. David Meyerson: -- or an angioplasty or work done on the carotid arteries which we can either stent or fix surgically or there's a lot of what we call endovascular procedures.  If you had an abdominal aorta aneurysm through an artery, you can place a graft without a major open surgical procedure, but again as Kerry's saying, then once that's done, the work still begins.  The blood vessels are still at risk for things happening. If you're a diabetic, we must control the diabetes really well.  People with diabetes get heart and blood vessel disease and lower extremity disease even more so than the rest of the population and our diabetics have to be especially careful because they get neuropathy and they can perhaps in the distribution where a sock would go on, they may have less sensation. And I remember a patient that I had who his daughter was playing with jacks, you know onesies, twosies, threesies and he happened to have stepped on a jack in his living room and it causes --

Dr. Kerry Stewart: This living room, by the way, was in that sixty year old house.

Dr. David Meyerson: Exactly right.  And he got a sore there, tried to clean it up, but didn't realize that over time because of his neuropathy, he didn't feel that the infection was there, it was getting worse, etcetera, etcetera and lots of people can have wounds on their feet --

Dr. Kerry Stewart: Absolutely.

Dr. David Meyerson: -- and, or even toe that's turning blue for example and unless you take a look -- diabetics need specialized foot care -- you have to be very careful about this.  If you see something like that, if you're diabetic, you want to be screened for these diseases, you must stop smoking, cholesterol control, blood pressure control.

There's a whole litany of medications that can be used and especially in the lower extremity issues.  Kerry, exercise for people with claudication sometimes does all that they need, medicines, prevention and an exercise program and they can return to near normal.

Dr. Kerry Stewart: Absolutely.  Exercise is probably one of the most powerful treatments for managing, not only peripheral arterial disease, but also heart attack.  And there's been numerous studies now showing that exercise has benefits, not only for reducing symptoms, but also reducing many of the risk factors such as high blood pressure, helping to control diabetes, helping to lose weight, particular body fat around the belly.

The was an article in today's Wall Street Journal all about how belly fat is such a risk factor for heart disease, stroke and other problems, so it's critically important that one stay physically active.

Dr. David Meyerson: Well, I think Kerry that we've covered our back to basics.  This has really been.a good foray if somebody hasn't been used to listening.to our programs before.  This gives a good flavor of where the problem is, what we call them and if you want to get a brochure that talks about this, let me suggest that you call toll free 866.PAD.INFO, I'll give you the.numbers on that 866.723.4636.  That's the Vascular Disease Foundation and you can go to their Web site at www.vdf.org or e-mail us at info@vdf.org.  We'd certainly like to hear your comments about our programs.  We'd certainly like to address any new issues that you haven't heard in our series and we're very, very grateful to the Vascular Disease Foundation and enjoyed bringing you this information because we do know that when the public can put this all together in their minds, they will act, do better for themselves and the Vascular Disease Foundation is all about promoting health, promoting high functional capacity, long life and good health and for the Vascular Disease Foundation, for Dr. Kerry Stewart, I'm Dr. David Meyerson, thanks for listening.

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