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Episode 20 : Abdominal Aortic Aneurysm Part 1

Release Date: August 8, 2007

Dr. David Meyerson: Hi, I'm David Meyerson, cardiologist at Johns Hopkins and your host for this edition for Vascular Disease Foundation's HealthCast. Our goal is 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 premiere 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. Our last twenty PodCast episodes are easily accessed by the Vascular Disease Foundation's website, www.vdf.org, www.vdf.org.

Recall that our previous episodes have dealt with topics like carotid artery disease, that's the narrowing of the arteries in the neck that nourish the brain which can cause strokes and threaten strokes called transient ischemic attacks or TIA's. We've talked about coronary artery disease, narrowings of the arteries that nourish the heart muscle that can cause angina, the chest pain you get when too little blood supply and oxygen gets to your heart muscle. They also cause heart attacks. We've talked about peripheral arterial disease, narrowings or blockages of the arteries that nourish the legs which can limit your ability to walk, cause pain and ulcers of the legs and in extreme situations, can even cause one to risk amputations. These are largely preventable diseases. Once developed, they're very treatable diseases and the early recognition and treatments can prevent your disability, promote your physical well-being and help you maintain the healthiest and most active lifestyle you possibly can. We've used the analogy of the sixty- year-old house. If the plumber tells you that certain of the pipes in the basement are corroded and clogged, it shouldn't surprise anyone that the pipes on the second floor or the first floor are also at risk.

Today we have some very special information and from a new very special breed of doctor. We'll be talking about abdominal aortic aneurysm, a bulging and weakening of the major blood vessel of the abdomen which can cause life threatening blood loss and other circulation problems. This special information comes from a very special guest. She is Dr. Elizabeth Ratchford and she's one of the new breed of physicians trained as internists, not as surgeons, who are expert in the prevention, diagnosis and treatment of blood vessel diseases. She's Director of the Clinical Vascular Medicine program at Johns Hopkins; she's also a scientific advisor to the Vascular Disease Foundation. Dr. Ratchford, Elizabeth, welcome to the VDF HealthCast microphones.

Dr. Elizabeth Ratchford: Thank you, it's a pleasure to be here.

Dr. David Meyerson: Before we concentrate on today's topic, tell us just a little bit about this new breed of vascular physician I spoke about. What training is involved and where did this develop from?

Dr. Elizabeth Ratchford: Well actually the field has been around for quite a long time, especially in Europe where it's called angiology and it focuses as you said, on the noninvasive side of the diagnosis and treatment of vascular diseases. It was first recognized by the American Medical Association in 1998 and then the first board exam was offered in 2005, so it's a relatively young, but rapidly growing field.

Dr. David Meyerson: It's a new breed for the United States is appropriate terminology.

Dr. Elizabeth Ratchford: Yes, definitely. And the training, there are a few fellowship programs around the country. The major centers are Cleveland Clinic and Mayo Clinic, Stanford and Brigham. Those are the largest programs.

Dr. David Meyerson: Very good. Now lets go on. As an expert in this area, we're going to talk about the abdominal aorta and this is about as big a blood vessel as we have in our body. The only larger one being the more proximal aorta where the blood leaves the heart to be distributed through the rest of the body. So just so our audience has a really good mental picture of where we are and what are the major blood vessels near this region. Let's follow the blood for a moment as it leaves the heart. So, it leaves the heart, it goes past aortic valve and it goes into the aorta. The aorta's the big blood vessel that is the conduit that all oxygenated blood gets, uses to get to every area of the body. It forms an arch, it goes to --it gives you arteries that nourish the brain called the carotid arteries, it gives arteries called the subclavien arteries which nourish both arms and then it -- as it's doing this, it makes an arch and it goes downward. And then, the big aorta gets a little bit more narrow, but not too much. It gives you the blood vessels that feed the digestive organs and then finally it gives you the arteries that nourish the kidneys. And take us from there, because right now we're in the abdomen. We're just below where the kidney arteries take off. We're not that far from the middle of the abdomen or even the bellybutton for most of people, so tell us -- that's where we're concentrating on today. What happens after that?

Dr. Elizabeth Ratchford: Well, that's actually the spot that's the territory at risk, right below the kidney arteries, between the kidney arteries and between that and where the aorta bifurcates or splits into two which happens at the bellybutton.

Dr. David Meyerson: So then, the aorta does split and as Yogi Berra said, "When you get to the fork in the road, take it," so the aorta actually does this and then it gives rise to the iliac arteries and the femoral arteries which nourish both legs, so it really, it forms just like a human form. It kind of splits and gives rise to the blood vessels that nourish both legs. Why is the abdominal aorta down around where the bellybutton -- we call it the umbilicus, but for the purposes of this discussion, bellybutton works just fine. Why is that area of the aorta so at risk? And let me ask an interesting question, if human beings did not walk erect, if we walked on all fours, would it also be at risk? You may or may -- it's an interesting question to ask, but I don't know if you have the answer, but why is that area at risk for normal human beings?

Dr. Elizabeth Ratchford: Well, there's a lot of theories about what happens to break down the wall of the arteries and nobody really knows the answer, but one of the problems is that the blood vessels that actually nourish the blood vessel itself are thought to be sort of few and far between in that area and that can lead to some of the weakening, but there's a lot of people who spend their whole lives trying to figure out exactly why those --

Dr. David Meyerson: Are those the vaso vasorum?

Dr. Elizabeth Ratchford: Yes.

Dr. David Meyerson: I can't believe I remember that from anatomy.

Dr. Elizabeth Ratchford: And also, usually when anything goes wrong with the blood vessel, then it has to do with the local sheer forces and things like that so whenever there's turbulence or any kind of disruption in the blood flow, then that impacts the wall as well.

Dr. David Meyerson: And so, any situation that would be more likely to make other blood vessels harmed would also predispose to harming the abdominal aorta?

Dr. Elizabeth Ratchford: Yes.

Dr. David Meyerson: But more so in that one area. Is that right? Because we do get aneurysm --what's an aneurysm?

Dr. Elizabeth Ratchford: So, an aneurysm is a really a bulging or a ballooning out of the artery and that involves all three layers of the wall of the artery.

Dr. David Meyerson: Does it look like --remember the old-fashioned tires when they had an inner tube and the tire erodes out and you see a bulging of the inner tube through the wall and that is a very weak wall when it's stretched and it's prone to rupture, is it not?

Dr. Elizabeth Ratchford: Yes, that's one of the risks.

Dr. David Meyerson: And that's one of the bigger risks of abdominal aortic aneurysms.

Dr. Elizabeth Ratchford: Absolutely.

Dr. David Meyerson: What other things can happen with -- sometimes they call it a triple A or abdominal aorta aneurysm, so they can actually rupture and bleed and that can be life threatening.

Dr. Elizabeth Ratchford: Yes, that's almost always life threatening. Only about forty percent of the people who experience the rupture survive to get to the hospital and then there's a fifty percent mortality among those people if they actually make it to the hospital.

Dr. David Meyerson: So, in a movie that we once referenced called War Games. It was a great – it was a very interesting movie -- and its premise was, which side would win global thermal nuclear war, from what theater of operations, whether if somebody threw land-based missiles or sea-based missiles, if they just a little salvo where they tried to annihilate and at the end of this movie, and this is the point, the computer says to its programmer in a computer-type voice, it says, "Dr. Falken, I've come to the conclusion that the only way to win this game is not to play it." So you're telling me that the best way to win the abdominal aortic aneurysm rupture game, is not to ever let it get that far.

Dr. Elizabeth Ratchford: Exactly.

Dr. David Meyerson: And that's what we're all about in trying to diagnose early, find out who's at risk, do whatever we can to prevent them from progressing and in fact, those people that need to be fixed in one way or another, we have to get them to the right place as well.

Dr. Elizabeth Ratchford: Right.

Dr. David Meyerson: Very good. Is this a common problem in the United States?

Dr. Elizabeth Ratchford: It's common once you get older. It's quite uncommon before the age of sixty, but they're certain risk factors that people have that increase their risk such as smoking and that's determined by the number of years that you smoked and in addition to how much you smoke and that risk decreases after you quit smoking. But that's one of the most important risk factors, so among older people, people over age sixty who smoke, then it actually becomes a common problem. There's about fifteen thousand people who die from rupture a year. The risk is one in a thousand between the age of sixty and sixty-five to have a triple A, but that markedly increases with age.

Dr. David Meyerson: And what we'll discuss in the next several minutes is how our audience can go about being screened, know what the risk factors are, what to look for and then probably in our next episode, we'll actually discuss medical treatments and how to follow these maybe to prevent them from ever becoming troublesome. So, it is reasonably common, it sounds to me like the same critical things that cause blood vessels to be damaged in other areas of the body, are pretty much -- so hypertension would be an important -- somebody who's very hypertensive, who's a smoker would be more likely to develop abdominal aortic aneurysm?

Dr. Elizabeth Ratchford: That's true, although hypertension is -- that person may be more at risk for something like aortic dissection and hypertension, although it does slightly raise your risk, it's not nearly as important as age or smoking and then gender makes a big difference. Triple A's are four to five times more common in men than in women. And then family history is also --

Dr. David Meyerson: Is it hereditary?

Dr. Elizabeth Ratchford: It is. In fact, if you have a sixty-year-old man who has a brother with triple A, the risk can be as high as eighteen percent for that person to develop an aneurysm as well, so that's actually more important than cholesterol or high blood pressure and strangely we don't really know why, but diabetes tends to decrease the risk of having a triple A.

Dr. David Meyerson: Finally diabetics get a deal, right? Finally, because unfortunately diabetics get hardened blood vessel disease of other types in every area of the body far more frequently than the rest of our population, so it's good to hear that they may have a little bit of a break at some point. Are there any symptoms of an abdominal aortic aneurysm?

Dr. Elizabeth Ratchford: Most of the time, there are no symptoms and a lot of the time it's --

Dr. David Meyerson: Until it's too late, is that what you're telling me, or nearly so?

Dr. Elizabeth Ratchford: Right. Usually people will just come in with it ruptured or often they'll have the aneurysm discovered just incidentally when they're having another test done for another reason like a cat scan or an MRI or an X-ray. But if people do have symptoms, then it's usually abdominal pain or back pain and sometimes you can get symptoms, if it's really large that can compress other structures in the belly and cause symptoms and then sometimes the aneurysm itself can be tender. I think also people worry if they can sometimes see their belly moving if they're lying on the ground, for example and --

Dr. David Meyerson: And they're not pregnant.

Dr. Elizabeth Ratchford: Right. And in thin people it's normal to be able to see the pulsations of the aorta, so that's not --

Dr. David Meyerson: This leads me to one other question. How good is the -- we've talked in this program before about blood clots that occur in the legs and the reason I'm bringing this up now is that what we learn from screening, looking at blood clots in the legs, that the physical examination is notoriously poor for the doctor to be able to say, "Yes, you have a blood clot in the leg" or "No you don't." It goes by index of suspicion and then you have to do some noninvasive testing. It's very sound wave test, no discomfort, no risk to the test, but the physical exam in that situation was notoriously poor for predicting who would have a blood clot in the legs. How is the physical exam in somebody with an abdominal aortic aneurysm and does it depend upon the body habitus is a large person, you really don't know, is it in a small person, if the contour of the pulse that you feel in the abdomen is wide, is that a good predictor? How good is the exam?

Dr. Elizabeth Ratchford: It's pretty bad. And about thirty percent of people who are diagnosed with triple A's will have been diagnosed because of their doctor felt something on physical exam or because maybe they noticed something that they brought to the doctor's attention, but in terms of a screening test or using that, it's just not sensitive enough to really diagnose it. And particularly in people who have larger abdomens as most of the United States is getting these days then it becomes even more difficult to diagnose it by palpation. However, larger aneurysms are obviously more easily felt than smaller ones, so they say that it's moderately sensitive for diagnosing an aneurysm that might need surgical repair, but it's really not adequate.

Dr. David Meyerson: Again, it's one of those areas where the doctor and the patient together have to look at the risk factors, they have to develop an index of suspicion and very often a simple, not very expensive, noninvasive test with no risk and no discomfort is really the best way to make this diagnosis. Is that right?

Dr. Elizabeth Ratchford: Absolutely.

Dr. David Meyerson: Okay.

Dr. Elizabeth Ratchford: Physical exam is really not the way to go. Ultrasound is by far the most important test.

Dr. David Meyerson: And we're going to get to that in just a minute, but are there other diseases that people have that would predispose them to abdominal aortic aneurysm or are there other diseases that if a patient has them, then they should definitely be screened for abdominal aortic aneurysm? In other words, if somebody has carotid artery disease, should they also have an ultrasound to look at the -- or there other diseases, maybe some of the collagen vascular diseases, some vasculitis disease. Are there others that say you should be screened?

Dr. Elizabeth Ratchford: Well, among people who absolutely should be screened, I would focus mainly on the people who have a family history. Anybody over age fifty who has a first degree relative with an aneurysm should definitely be screened and then the smoking.

Dr. David Meyerson: And just so that our listeners are clear, first degree relative means --

Dr. Elizabeth Ratchford: Like brother, sister --

Dr. David Meyerson: Brother, sisters, somebody close like that.

Dr. Elizabeth Ratchford: -- mother, father, son, daughter.

Dr. David Meyerson: Okay.

Dr. Elizabeth Ratchford: Uh-huh [affirmative].

Dr. David Meyerson: But not second cousin twice removed or something like that.

Dr. Elizabeth Ratchford: Right.

Dr. David Meyerson: People who are you immediate blood.

Dr. Elizabeth Ratchford: Right.

Dr. David Meyerson: And if somebody has -- we've talked about this program about ABI, an ankle- brachial index, and one of our guests actually mentioned that the ABI should be the EKG for a vascular medicine doctor and that that compares the blood pressure in the arms and the blood pressure in the legs and it really is very predictive of who has peripheral vascular disease. If somebody has an abnormal ABI, would that also be an indicator to look at the abdominal aorta?

Dr. Elizabeth Ratchford: Yes, the risk of triple A in patients with peripheral arterial diseases is about ten percent, which is definitely higher than the baseline risk and then that's about twice as high as if you have coronary artery disease, or blockages in the heart arteries, it's about five percent, so just to give you an idea having the diseases of the arteries in the legs doubles it compared to just having blockages in the artery in the heart, which is also elevated and linked, you know, athroschlerotic vascular disease is what we like to call this systemic problem. And that definitely is closely associated with having a triple A, but the mechanism it is not exactly the same, but they are closely linked, so if you do have peripheral arterial disease, it's definitely something to think about as far as getting screened and then likewise if you have an aneurysm, then you need to think about the cardiovascular risk as well. And the other people who – if you have an aneurysm that's diagnosed elsewhere in the body, such as in the popliteal artery behind the knee, then those people definitely need to be screened for abdominal aortic aneurysms.

Dr. David Meyerson: So that is one area -- if you find an aneurysmal region below, then it may predispose to having an aneurysmal region of the abdominal aorta as well.

Dr. Elizabeth Ratchford: Right. About sixty percent of people with popliteal or the artery behind the knee, if you have an aneurysm, then about sixty percent of those people will have a triple A and the --

Dr. David Meyerson: Didn't the Vice President have something similar to that?

Dr. Elizabeth Ratchford: Yes he did, so I hope he's had his ultrasound.

Dr. David Meyerson: I'm sure he has. Let me talk a little bit more now with you about -- we've talked about abdominal aortic aneurysm and that's that bulging and you said it's a thinning and a bulging of all three layers of the aorta and that one of the risks of these is rupturing. Do they have other risks? We talked in previous sessions about something called aortic dissection and can the blood actually seek to go between those layers and then harm other blood vessels downstream, or does one generally not happen in the face of the other?

Dr. Elizabeth Ratchford: Aortic dissection and aortic aneurysm thus, I feel that was something in medical school that people always got confused and they were saying dissecting aneurysm and aortic dissection and aortic aneurysm like there were a lot of terms were thrown around and they really are two totally different processes. The main risk of the aneurysm is rupture. With the dissection, that's where the tear -- there's a tear in the inner layer of the wall and then it dissects down in between the layers, so they're two totally different processes, but --

Dr. David Meyerson: But you could certainly envision a process whereby the inner lining, the aorta's beginning to dilate, there is damage to the endothelium or the inner lining, and then it could really go in either direction at that point.

Dr. Elizabeth Ratchford: True.

Dr. David Meyerson: It could either, it could either disrupt under one level and the blood then peels away. It's almost like if you're a woman and you have a lined dress and the lining and the dress are supposed to be very close to each other, but something happens to separate those two and in the blood vessel situation, it would be blood and the force of the blood actually splits them, so you could see that happening from similar blood vessel disease, right?

Dr. Elizabeth Ratchford: Right. And that might be, you know, when it does actually rupture, that might be part of what's going on, although a lot of times an aortic dissection is more proximal or closer to the heart than the aneurysms are, but the -- I think another thing that you were going to bring up was the possibility of other symptoms that you could get with blood clots going to the legs.

Dr. David Meyerson: Exactly.

Dr. Elizabeth Ratchford: That would be in the arteries in the legs, not the veins, which I know you've discussed in other PodCasts, but the -- that is actually very common with the popliteal artery aneurysms. It's more common for the popliteal, the ones in the leg, to have what we call emboli or little pieces of clot that go down to the feet.

Dr. David Meyerson: So in the area where the blood vessel is damaged, there is, in part, turbulence and there's in part where the blood flow is kind of stagnant because it's not getting a lot of flow. And is that the area where the blood will tend to clot because blood that doesn't move, clots.

Dr. Elizabeth Ratchford: Yes and a lot of the aneurysms are lined with clot. That's a very common finding that we see when we do some of the imaging tests and that clot is not protective and also is thought to be one of the risks to weaken the wall further. But actually the --

Dr. David Meyerson: And can pieces, as you pointed out, pieces of that clot can shower down into the legs.

Dr. Elizabeth Ratchford: Yes.

Dr. David Meyerson: And if there -- if it's a large piece, what would happen?

Dr. Elizabeth Ratchford: You could get blue toe syndrome or any artery that you block in the --

Dr. David Meyerson: Or even a cold and painful leg, right?

Dr. Elizabeth Ratchford: Right. Although that's much more common to see with popliteal artery aneurysms than it is with the abdominal aortic aneurysms, rupture is really the biggest and most common thing that you would see from the abdominal aortic aneurysm.

Dr. David Meyerson: And what if -- you had mentioned that some of these are picked up by incidental finds. In other words, somebody has a cat scan or an X-ray of the abdomen for another reason and all of a sudden they say, "Doctor they told me I have calcium in my abdominal aorta, or they think it's bulging." That's another way people get picked up, is that right?

Dr. Elizabeth Ratchford: That's the large majority of cases these days because people end up getting so many imaging tests for other reasons and that's how most of the aneurysms are discovered and fortunately most of them are small at that stage.

Dr. David Meyerson: And there are a lot of, I've seen churches and other groups sponsor screenings and they're basically vascular screenings where they look at peripheral vascular disease, they look at the abdominal aorta, they look at the carotid arteries. What do you think about those?

Dr. Elizabeth Ratchford: I think they're great as long as you have good technologists who are doing the studies and you don't get a false sense of security from having a test that's done poorly that they tell you that you're fine, but I've organized some vascular screening days through the American Vascular Association, and other organizations when I was back at Columbia in New York and we had vascular screening days, which was great. I mean, it's very important to raise the public awareness about these diseases. As long as you have good technologists who do a good study, then I think it's great.

Dr. David Meyerson: That's wonderful. I can't believe that the time of our first episode on abdominal aortic aneurysm has evaporated already and we will absolutely continue this in our very next episode. My special guest has been Dr. Elizabeth Ratchford, a vascular disease specialist at Johns Hopkins. She's also a scientific advisor to the Vascular Disease Foundation. We hope this information has been a value to you, you've enjoyed our presentation format and please -- this is only part A of a continued discussion of abdominal aortic aneurysms and for the Vascular Disease Foundation, for my partner in these PodCasts, Dr. Kerry Stewart, I'm Dr. David Meyerson, have a great day.

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