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Interactive Learning : HealthCast Transcripts

Episode 11 : Deep Vein Thrombosis

Release Date: February 6, 2007

Dr. David Meyerson:  Hi, I'm Dr. David Meyerson, cardiologist at Johns Hopkins and your host for Vascular Disease Foundation's HealthCast.  We are privileged to bring you excellent quality and important medical information from peer-reviewed sources as a public service.  In each of our healthcasts, it's our goal that you learn something new or improve your understanding of something you thought you knew that you might save your life, preserve your functional capacity or do so for someone that you love.  Knowing when to seek medical care, when not to ignore warnings and when possibly to push your physician just a bit harder to investigate a problem may save you a great deal of pain and function.  Very often the outcome is dependant upon how a person responds to the warnings they receive and how they communicate them to the medical profession.  We want you to understand these red flags and when appropriate, act on them.  Let's start today's discussion this way.  Item number one for your consideration.  A blood clot sitting on a stomach ulcer preventing it from bleeding is your best friend. However, a blood clot sitting in an artery that nourishes your heart muscle and is causing a heart attack, is anything but.  Item number two.  The body is always forming blood clots in appropriate places and it is always dissolving blood clots that are not needed. This is always the yin and yang in the body, the balance is necessary.  In fact, we often give credit to scientists for inventing the special blood clot dissolving medication called tissue plasminogen activator which can be used to turn off strokes and turn off heart attacks.  In reality, this occurs naturally in our bodies in small quantities.  The scientists, of course, found it and found a way to genetically synthesize this in the laboratory so we could have enough to go around in large quantities to treat patients, but the actual credit goes to the body. Let's talk about certain blood clots for a moment. When a blood clot occurs in the brain and shuts off flow and causes brain dysfunction, we call it a stroke. When the same event happens in coronary arteries, we call it heart attack.  When it occurs in the arteries of the legs, the vessels that supple the oxygen rich blood to the legs, we call it critical limb ischemia. So far, what these have in common are that they're occurring in arteries, those vessels taking oxygen rich blood toward important organs.  Now when the blood clots occur in the blood vessels of the leg that return blood back up to the circulation, a whole different series of events can happen.  Venous thromboembolism, deep vein thrombosis, and pulmonary embolism are critical and under recognized health problems that are treatable and preventable.  Knowing about these can save your life.  With me today is an expert in this field and someone who has dedicated a substantial portion of his career to public education regarding the prevention of death and disability from these events.

With me is Dr. Robert B. McLafferty.  He is Professor of Surgery Division of Vascular Surgery at Southern Illinois University School of Medicine in Springfield, Illinois.  Dr.  McLafferty, thank you so much for being with us today.

Dr. Robert McLafferty:  I'm happy to be here, thank you.

Dr. David Meyerson:  Before we get into the more complex issues, let's talk for just a moment about an article that appeared in Time Magazine some time ago, the time is not important, but it was about people who were taking very long plan rides and developing swelling in their legs only to find that they ended up in hospitals with life threatening illnesses.  What was going on there?

Dr. Robert McLafferty:  Well basically, because people are not moving and are sitting in their seat for a long period of time, they may have a risk of developing deep venous thrombosis as you previously mentioned.  Not everyone is at risk of developing deep venous thrombosis, but depending on certain constellation of risk factors that may be occurring, people who are sitting or not moving for long periods of time can develop these blood clots in the veins which are the tubes that take the blood back to the heart.  As you know, we are victims of gravity and our veins have to work very hard to get the blood back to the heart and depending on risk factors, which I hope we'll touch on later today --

Dr. David Meyerson:  Absolutely.

Dr. Robert McLafferty:  -- we can – people can develop these blood clots in their legs.

Dr. David Meyerson:  Now I wanted to start there, Dr. McLafferty, for a reason and that is that these are occurring in largely of what we think of as normal people and so this is something that everybody needs to pay attention to, right?

Dr. Robert McLafferty:  That's correct. That's correct because if we look at what the actual risk of developing a deep venous thrombosis are --

Dr. David Meyerson:  Now just again, sometimes the words get our audience a little bit concerned, so deep venous thrombosis just means a blood clot forming in the inner veins, the deep veins of the leg.  That's all it means, right?

Dr. Robert McLafferty:  That's correct. That's correct.  There are both deep veins and superficial veins.  The deep veins in the leg tend to follow the same course as the arteries which are the tubes carrying the blood away from the heart, but the deep veins are those that connect to the larger veins in the pelvis and abdomen and up to the chest which can lead to further problems of pulmonary embolism which we'll also touch on today.

Dr. David Meyerson:  So in terms of the blood circulation, when you use the expression, all roads lead to Rome, the arteries take the blood to all of the organs and then the veins collect all the blood and the larger veins take the blood back upstairs to the more central portions of the body and back to the heart for recirculation.

Dr. Robert McLafferty:  That's correct.

Dr. David Meyerson:  And that's what we're talking about now.  So if we have a blood clot that has formed in the veins of the leg, what is the risk, what can happen if that clot dislodges?  What ultimately are we most afraid of?

Dr. Robert McLafferty:  Well, we're most afraid of that clot traveling to the heart and then from the heart to the lungs causing a pulmonary embolism and that can cause death and in America, it causes over fifty thousand deaths per year and if a deep venous thrombosis or a blood clot in the vein, deep veins of the legs develops and is not treated, a third of those people will develop a pulmonary embolism or blood clot to the lungs and of those clots that go to the lungs, fifty percent of people will die, so it's an extremely dangerous phenomenon that can occur in someone who develops this problem of deep venous thrombosis.

Dr. David Meyerson:  And I would hasten to say as a cardiologist that I am, and in our training programs as we train residents, interns, medical students and fellows, we -- and I'm sure you tell your trainees as well, sometimes these masquerade as other things.  Let's talk for just a minute about how difficult it is for the doctor to recognize a blood clot in the leg.  Now let's not talk about upstairs in the lung just yet, but let's go back to the leg.  How good is the physical examination?  The doctor looks at the leg and says there is a blood clot in that leg, there is not a blood clot in that leg.  How good is the doctor?

Dr. Robert McLafferty:  Typically the doctor is not that good in determining whether there's a blood clot in the leg.

Dr. David Meyerson:  And we're talking about a good doctor too.

Dr. Robert McLafferty:  Yes --

Dr. David Meyerson:  In other words, the physical examination just is not that sensitive or specific and it can masquerade as so many different things.  I guess sometimes people come to you with a redness and swelling of the leg and it turns out to be an infection of the skin we call cellulitis sometimes with a lot of swelling, is that right?

Dr. Robert McLafferty:  Yes, yes.  In fact, I just recently was taking care of a patient whom I was consulted on whose only symptom was some mild pain in the groin and, in fact, that patient went to his doctor and the diagnosis of a muscle strain was made and two days later that patient had two episodes of fainting from massive pulmonary embolism and when the appropriate tests were done, it was determined that there was a large amount of blood clot in the veins of the leg, so these things can masquerade in different ways and the number one way for a physician to diagnose it is to have an extremely high sense of suspicion and keep it high on the list of possible diagnosis.

Dr. David Meyerson:  I could not echo that sentiment more forcefully.  It is what we teach our interns, our residents, if you're not thinking about a deep vein thrombosis and pulmonary embolism, you will not make the diagnosis and Dr. McLafferty, this can be masquerading sometimes as just shortness of breath for unknown reasons.  As you pointed out, it could be passing out.  It could be that somebody has chest pain and you have to differentiate that pain from heart attack or other problems with large blood vessels, but it's very critical and as you point out, it's got to be high on the radar, so believe it or not if you're having chest pain and shortness of breath and you're going into the emergency room, Dr. McLafferty, would you ever say to our listeners, if you go in, make sure to tell the emergency room doctors and the people that are evaluating you that you've heard about deep vein thrombosis and pulmonary embolism, is it possible that this is what I have?

Dr. Robert McLafferty:  Yes, I think that that is the number one way to prevent pulmonary embolism or be aware that you may have a blood clot in the vein of your leg by educating the public.  I think that as the public becomes more aware of this problem and brings this to the attention of their doctor as a possibility, it will only improve our ability to help prevent people dying from this disease.

Dr. David Meyerson:  And this is something I mentioned in the introduction.  I said knowing when to seek medical care, when not to ignore warnings and when possibly to push your physician just a bit harder to investigate a problem and as Dr. Kerry Stewart mentioned in our last episode about another topic, but what he said essentially was what I said today.  Very often the outcome is dependent upon how a person responds to the warnings they receive and how they communicate them to the medical profession.  We want you to understand these red flags.  So Dr. McLafferty, this is a big problem.  How many deaths a year are we seeing from pulmonary embolism?

Dr. Robert McLafferty:  Well, roughly about fifty thousand deaths in the United States per year and deep venous thrombosis of DVT occurs in about three hundred thousand people per year.  To give you an idea, I think it's interesting to compare how common DVT is to other diseases.  The incidence of DVT is about a hundred per hundred thousand population per year.  Now if you look at things that the public may know about, breast cancer is exactly the same.  It's a hundred cases per hundred thousand people per year if you --

Dr. David Meyerson:  And that, of course, is on every woman's and her loved ones radar.

Dr. Robert McLafferty:  That's correct, whereas DVT which is as common, is not really a household phenomenon, but as common and as lethal.  If you look at other things like kidney failure, it's about fourteen cases per hundred thousand per year, HIV is twenty-four cases per hundred thousand per year, so these things certainly are more common in the press and the public is more aware of them, but DVT is a very lethal problem and also a very debilitating problem for people who don't die from this problem, is extremely common.

Dr. David Meyerson:  So the first thing to do is to properly recognize if you could possibly have a DVT.  What would be some of the things that we might key our listeners in to be sensitive to if they should seek medical attention.  Tell us about that.

Dr. Robert McLafferty:  Well, I think that if someone seeks medical attention or is ill, they should be aware that the large majority of those people are probably at some or risk, either a low to very, very high risk of developing venous thromboembolism or DVT, things like having major surgery, having the diagnosis of cancer, being in a car accident or a trauma, there are certain medical conditions that can predispose to getting DVT such as congestive heart failure, or inflammatory bowel disease.  There are certain medicines one can take such as birth control pills or estrogen replacement for women --

Dr. David Meyerson:  Don't forget smoking.

Dr. Robert McLafferty:  -- and smoking's on my list as well, obesity puts people at increased risk and just increasing age.  If you look at the incidence, those numbers I gave previously, the incidence in someone twenty to thirty years old is about twenty to thirty per hundred thousand.  If you look at someone in the age of seventy to seventy-nine, the incidence of DVT is three hundred to five hundred cases per hundred thousand per year.  So for us physicians in the hospital caring for patients of which the majority are elderly, we need to have DVT and pulmonary embolism as a entity that is extremely high on our radar screen.

Dr. David Meyerson:  So some of those things that you mentioned, for example, an orthopedic injury or any illness or injury where somebody is laid up in bed for several days time and they're not ambulatory or they have some sort of compression or swelling or breaking a bone of a lower extremity, these things really do predispose people to blood clots forming in the legs.

Dr. Robert McLafferty:  Absolutely.  I think if we go back to something that medical students learn, Verchow's triad which is essentially three different things that may lead to deep venous thrombosis.  Its stasis of the blood which means that the blood is not moving very quickly and that can occur from someone who's having a prolonged bed rest or in a long plane flight.  There's hyper coagulability which is a medical term that states that the blood has a tendency to clot and conditions such as cancer can predispose to that. And then there is injury to the vein, such as trauma or some sort of surgery that may occur on the vein or a needle puncture to the vein.  So there are these different entities that can occur that can lead to someone having deep venous thrombosis.

Dr. David Meyerson:  We almost never think about this, but I can tell you that I've read about a couple of cases recently where somebody had a heart catheterization and because they often go into a vein as well as an artery in the leg in that same area, again that's a trauma to the vein.  That's not to say that if the doctor tells you, you need a catheterization you shouldn't have it.  You absolutely should have it, but as Dr. McLafferty says, any time a vein is injured either with a trauma, a motor vehicle accident, being in bed for a lengthy period of time, terrible swelling of the legs, all predispose, heart failure and cancers, all predispose to this.  So Dr. McLafferty, you teach your trainees as well and that we have to keep the highest index of suspicion and as we do and you would to our listeners, if a loved one is in the hospital, if they've had an orthopedic surgery procedure, if they've had a broken hip, if they've had any situation that puts them in bed, it would be very reasonable in your estimation to ask the doctor, "What are you doing to prevent blood clots in the legs and to prevent them from traveling to the lungs?"

Dr. Robert McLafferty:  Absolutely.  I think that is the key to preventing this disease and preventing death from this disease is to have patients educated about it and ask their doctor, do I need to be treated or have anything done to prevent me, the patient, from getting a blood clot.  That is extremely important because there are studies that have shown that generally, doctors don't do the greatest job at making sure that patients are receiving the appropriate treatments to prevent blood clots in their legs which can lead to -- in their veins -- which can lead to pulmonary embolism.

Dr. David Meyerson:  And part of that as medical educators, this is in part our problem.  We have to make sure that this information is disseminated to younger doctors, to older doctors, to training programs throughout the country and to nurses and to other health care professionals to recognize deep vein thrombosis and -- because this is preventable disease and pulmonary embolism, the deadly sequella of this is preventable disease.

Dr. Robert McLafferty:  I often tell the fellow that's training with me and the residents that the first thing that they should think of on any consultation of the hospital, in the hospital to see a patient is as they walk through the door, the first thing they should think about is what is being done to prevent DVT in this patient.

Dr. David Meyerson:  And I would echo that by saying don't be afraid to tell and ask your healthcare provider, the nurse, the doctors in the hospital and anyone -- raise the question.

Dr. Robert McLafferty:  Absolutely.

Dr. David Meyerson:  -- what is being done to prevent this?  It is a very valid question and the more it is on the medical profession's radar, the better that we can protect the patient and the more the patient knows, the better off they are.

Dr. Robert McLafferty:  Absolutely.

Dr. David Meyerson:  Well, Dr. McLafferty, believe it or not, we've exhausted the time for our first episode, but you've graciously agreed to continue on in our next episode and when we return, we'll continue our discussion of venous thromboembolic disease and we'll discuss how to recognize it if you have it at home, when to ask for help, what you can do to prevent, and to properly treat this disease.  Until next time, for the Vascular Disease Foundation, I'm Dr. David Meyerson wishing you good health and have a great day.

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