Section: CME Category: Vascular

DVT - Prophylaxis, Diagnosis and Treatment

Michael Troiano, DPM

Michael Troiano, DPM discusses the identifiable risk factors, prophylaxis, and treatment of deep vein thrombosis.

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Goals and Objectives
  1. Identify risk factors for the development of deep vein thrombosis (DVT)
  2. Understand the surgeon’s role in DVT prevention
  3. Discuss ways to prevent DVTs based on patient’s history, risk factors, and type of surgery.
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    Release Date: 05/11/2018 Expiration Date: 12/31/2020

  • Author
  • Michael Troiano, DPM

    Center for Foot and Ankle Disorders
    University of Pennsylvania - Penn Wound Care
    Adjunct Clinical Professor, TUSPM
    Philadelphia, PA

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    Michael Troiano has disclosed that he is a consultant for Stryker and Smith and Nephew.

  • Lecture Transcript
  • TAPE STARTS – [00:00]


    Unidentified Male Speaker: For them you're going to find that. It's a very, very serious problem. Having had pulmonary emboli myself, you know how serious a deep vein thrombosis can be and it's our job to detect this when present and treat them promptly and adequately. So Dr. Michael Troiano is going to conduct and talk to us about DVT risk assessment diagnosis and treatment. So let's welcome Dr. Troiano once again. You're not going to talking about surgery on DVT, so.

    Michael Troiano: A little bit. So in association with what [Dr. Friedberg] [0:00:46] discussed with us, a good friend of mine, 38 years old had a flu this past week and went to the hospital and shot a Tamiflu when he was sick and he came home and he was lying around. And that night he had trouble breathing and spit up some blood and was gone within about four hours from a DVT that turn into a PE. These things moved pretty quickly. And unfortunately, we probably as a podiatric physicians cause a fair amount of them even if you're not doing surgery on someone, think of what you're doing with them.

    Someone comes in with tenosynovitis, what do you do? You put them in a CAM walker, you put them in a cast, you put them in a soft cast, Unna's boot, what have you. And do we really ask ourselves, is this person a little heavy set? Do they – did I interview them about their family history? How'd mom pass away? How'd dad pass away? People say cancer, but maybe that cancer led to a DVT, which killed them. So you really want to get into the meat and potatoes of that patient. Venous thromboembolism falls into two categories, the DVT and the PE.

    [02:00]

    We're going to discuss each of these and how we can adequately identify them. Pulmonary embolism remains the most common preventable cause of hospital death, 150,000 to 200,000 deaths per year in the United States. A lot of these can be caught before they propagate to a PE. So to review the venous thrombosis in the deep veins in lower lumbar pelvis, these are the guys that we're worried about. The iliac vein, femoral vein, popliteal vein, greater saphenous vein put really these guys here. From here south, we don't really worry about these too much. They're of concern and we need to treat them, these will you – these will take some time to kill you, emergency, nonemergency.

    So the difficulty is telling the difference of the two in the patient in front of you clinically. So a gentleman asked earlier, what do you do? You know, usually if I suspect a DVT, I give a patient a script and I send them to the vascular lab and it might be a day or two should I give Aspirin. The answer is, no. The answer is you don't send them to the vascular lab. Unless you call the vascular lab first and say, "Hey, this is Dr. Smith and I have a guy that I think has a DVT, can you see him immediately?" Because I've been in situations even where I've sent people to the vascular lab and then they turn around and say, "Oh, he needs a referral with his insurance, you know, having to get one and he'll come back in a couple of days."

    These people have to understand that this could very quickly turn into a life threatening emergency. Forget about losing your leg, life threatening. So if that person doesn't have Medicare where they don't need a referral or what have you or if that person doesn't have, or if that vascular lab cannot see the person on the spot, I send them to the emergency room immediately without any inkling of otherwise because all we have to do is lose one patient from a DVT and you – or from a PE and you realize how big of a deal it is.

    [04:04]

    Two types of DVTs, unprovoked and provoked. No identifiable provoking environmental event for DVT. This is the person who is just hypercoagulable, Factor V Leiden deficiency, Factor XII disorder or what have you. And there's provoked, surgery, hospitalization, immobilization and the worst part is, is what's provoked to me may not be provoked to you. In other words, a plane ride for four hours might do it for me and for you it maybe, you're able to fly across India and back and never get up one time and not get the DVT. So you don't really know who's susceptible to it, unfortunately. Again, we have the proximal popliteal femoral or iliac veins and then confined to the cath veins or the isolated. Isolated, we don't worry about so much.

    We do treat, okay and obviously, we're going to use the person's primary care doctor for some input, but the proximal DVTs are the ones that are really, really of concern. And they're symptomatic and asymptomatic, right? So incidental finding versus symptomatic DVT and not everybody has the same degree of symptoms. So if somebody with a red hot swollen painful cath, one person is in excruciating pain, and the next person with the same DVT in the same location might say, "It's about a two or three, it's a little bit crampy, but it might just because I was having spasm or Charley horse," is how they describe it.

    DVT obviously may embolize to the other parts of the body. Most concerning is the lungs, it can block the pulmonary arteries, but one or both. Virchow actually is credited for this triad of who is going to be more susceptible to DVT, but really never made this triad. This was developed about 25, 30 years after he died, maybe a little bit less. But the triad that we learn in school is venous stasis, vessel wall injury, hypercoagulability state, all of these equal a DVT. And you have to be cognizant and review that patient about which of these they have.

    [06:09]

    So you're going to use your eyes to look for venous stasis, the hemosiderin in the skin, the edema that they may have in the beginning, hypercoagulable state. You're going to listen to your ear – you're going to use your ears to listen if they have a history. Asking family history, have you ever had a DVT? And then vessel wall injury. Why are they there in the first place? Did they have a trauma where they, you know, broke their ankle and you put them in a CAM walker, where they in a car accident, slamming on the break very quickly, is there a reason for them to have this DVT? And once you look at these three things is that's how you're going to decide who you shouldn't – should not coagulate – anti-coagulate, excuse me.

    Risk factors, inherited is 24% to 37% of the cases. Factor V Leiden deficiency, protein S or C deficiency, antithrombin deficiency, prothrombin gene mutation. So obviously, any of these and really this one is on the cusp. But any of these most of the time, you're not going to know until the person already has a DVT. And you're going to say, why, why did they get the DVT? And then you're going to send them to the hema doctor who's going to order all these things and you're going to find out that they are hypercoagulable. So like on Friday, I just operated on a 40-something-year-old woman who said, "I had a DVT that turned into a PE."

    But before I operated on her, I want to make sure why, right? She's not chubby. She doesn't smoke. She was immobilized. She wasn't on birth controlled pill. But I want to know, does she have any of these, because if she does have these, it's not as simple as just giving her some Xarelto or Xa Lovenox. We may actually want to treat her prophylactically for this DVT before it even occurs. She may want to be on Coumadin in that post-operative period. We may want to give her therapeutic Xarelto or therapeutic Lovenox. So in actuality, we have to identify these things.

    [07:56]

    So risk factors acquired, the section required comes in or comes under malignancy, surgery, trauma, CHF, sickle cell anemia. And then of course, the I am clotted mnemonic is what we learn in school, right? If this is the mnemonic immobilization for the eye, atrial fibrillation, malignancy, coagulopathies, longevity or age, obesity, trauma surgery and this doesn't necessarily mean surgery, this can just mean person is casted, tobacco or travel, estrogen, oral contraceptive, pregnancy, DVT, PE history, I am clotted. Simple stupid, we should be going through this with every one of our patients that we see that we're going to immobilize even if it's for a small injury.

    The Caprini score for DVT risk, I have this hanging in my closet in my office because I referred to it anytime just to refresh my memory. Give myself a little score of where this person is. These slides are available online of course. It's a point based score. I'll even document it in the note where they, you know, my patient note and I'll identify their very low risk via Caprini score or high risk and that's why I'm putting them on, on what have you. Now, we'll get into Aspirin and where that stands in things, but don't be afraid to write for Lovenox. Don't be afraid to write for Xarelto.

    But if you do so, make sure you document that you've told the person that they are not on any anti-coagulant and should they strike their head or fall or cut themselves. They're at a higher risk for an untoward event so they know that it's serious. People die from subdural hematomas and hemorrhages as well from being over coagulated, so something to consider. The American College of Chest Physicians has categorized people into low risk, moderate risk, high risk and non-orthopedic surgery. We fall into the orthopedic surgery obviously. The one that I would really call your attention to is one that was in JFAS. This is actually very, very good stance.

    [10:04]

    JFAS, foot and ankle surgeons, right? And the consent statement is the following. Decision to prescribe chemical prophylaxis during non-operative or operative management, the foot and ankle disorder should be based on each patient's unique risk benefit analysis, i.e. see your score, right, Caprini score. This involves weighing the risks and consequences of bleeding against those of developing venous thromboembolism disorder, exactly what constitutes significant risk to warrant chemical prophylaxis is not clear. Factors associated with the greatest risk include personal history, active or recent cancer, hypercoagulable state and prolonged lower extremity mobilization.

    What's prolonged? A week, two weeks, a month, six weeks? Very lose. But this will come back and bite you because this is now in our podiatric foot and ankle surgery lore, right? When you have that DVT, everyone is going to go back to this. So document why you did or did not coagulate or anti-coagulate this patient. Which methods, okay, this is important as well out of the same article. Multi-modal approach, prophylaxis is recommended for patients at high-risk. This includes addressing any modifiable risk factors using mechanical prophylaxis so your nurses in your operating room are going to give you your compression garments, right, while the person is lying on the table.

    Early mobilization, so even when I do surgery, as soon as I take the person out of the cast to check the incision a week or two, they very rarely go back into a cast. They go into a splint and I say take the splint off and I want you to do the alphabet, gentle range of motion. Considering the use of chemical prophylaxis, low molecular weight heparin, that's Lovenox, right? Is effective that reducing the rate. Also likely to reduce the rate of PTS, there's currently insufficient evidence to support the use of Aspirin.

    [12:00]

    Read that again, this is our colleagues. There's currently insufficient evidence to support the use of Aspirin as an isolated measure of prophylaxis in high-risk patients. So that will come back and bite you, right? Placement of IVC filters is discouraged and should be reserved only for patients at highest risk when chemical and mechanical prophylaxis are not an option. Prophylaxis again, these are the stockings. This is the sequential compression devices, SCDs. A patient is going to be on the operating room and when you admit the patient to the hospital, you're not working with a residence or you are, you want to make sure that they order them.

    Low molecular weight heparin, everybody hates Lovenox because I got to give myself a shot in the belly. Well, at least if you prescribe it, that's all it really matters, right? I mean, this person has to know that this is proving efficacy to reducing the incidence of DVT. And I've had patients even get a DVT with using Lovenox, but at least they are treated appropriately giving them what they need to get to the show. Unfractionated heparin has some issues, the cost is a little bit better. Most insurances are covering it, but you have to be aware of this person's creatinine, their kidney function because it can affect their kidney function.

    And you have heparin, which is not so much depending on kidney function, but has to be given more times a day so the outpatient setting is not realistic and you have to consider your Xarelto. Direct thrombin factor Xa inhibitors have not been studied in general surgical population. Warfarin, if you can bridge to Warfarin that person is in the hospital for a little bit, it's not a bad choice, it's very cheap, but you or the primary care doctor or your Coumadin clinic has to monitor it. So it takes a little bit of goings on shall we say so that you're getting those faxes on a weekly basis, God Bless you or you're getting that patient to report to you their INR after it was drawn.

    [14:02]

    Therapeutic is in between two and three, right? Aspirin again can be consider for orthopedic patients who have undergone a total hip or knee replacement, insufficient evidence in use after foot or ankle surgery. It doesn't mean it's wrong to use it, it doesn't mean it's right to use it. So to say, "Oh, I put the person on Aspirin," should be followed up with, "I put the person on Aspirin and they had a low score," right? If they have a high score, Aspirin is not appropriate. Extended prophylaxis, the optimal duration of extended prophylaxis is unknown, given beyond 10 days and up to 35 days following major orthopedic surgery. What we do is by enlarge, major orthopedic surgery.

    Wells criteria, very similar, different scoring. Validated clinical model for estimated pre-test probability of DVT. So this is pre-test, all right. And again, you can get the slides offline, but I want to show you what you get scores for very quickly. Pitting edema confined to the symptomatic leg, all right? This is who you're going to order your ultrasound on, not who you're going to prophylax, but who likely has the DVT. Active cancer, paralysis, recent plaster immobilization or lower extremities, localized tenderness, entire legs swollen, so each one of this is going to give you a point, and then, negative two and a score of two or higher. So only two of these and I bet everybody in the room probably has two of these at some point in their lifetime, right?

    Recent cast, entire legs swollen, so you want to document these things as to why. So I prophylax this person with Aspirin based on their score. They showed up to me postoperatively and based on their Wells criteria. Although I've documented some edema, I've documented some erythema, its normal post-operative course and does not satisfy Wells criteria for an ultrasound. I do it all the time. This is an algorithm diagnosis, patient risk stratification they get bucketed into low, moderate and high buckets and then from there, we can go down each.

    [16:08]

    Ultrasound is very easy and we're going to get into it. D-dimer is even easier. The problem with the D-dimer is if you've ever had surgery in the recent past, it's going to elevate in a D-dimer. So you'll get a false positive, but I rather get a false positive than a false negative. D-dimer's negative test is valuable in ruling out a DVT, low false negative, right? So if the D-dimer is negative, you can safely put away DVT. However, if it's positive, you can't rule out a DVT. High false positivity results, so sometimes you order the D-dimer. You say, "Man, its positive." You send them for an ultrasound anyways, right?

    But if it's somebody that really doesn't satisfy many of that Wells criteria, D-dimer is not a horrible choice. Because you can get them in for that blood test and get it back the same next day if you can't get them into that lab and they don't satisfy Wells criteria, but you have to identify that they are swollen and they do have a little cath pain. When in doubt, send the person in emergency room. Compressive ultrasound on lower extremity veins, this is what a – when you send that patient for a duplex, venous duplex study or an ultrasound study, this is what they are doing. The lab tech where the ultrasound tech he or she is literally taking an ultrasound probe and smashing the vein up and down, very slowly.

    The artery, which is this guy here with the red blood, he's never going to compress. The vein, you're going to see wall to wall touching. When you see this white speckling throughout the vein and it's non-compressible, DVT. So certainly, if you have an ultrasound in your office, you can check preliminarily to see if that vein collapses, I'm sure you're – if you have an ultrasound in your office you know how to do that already. But really, you want to get that person to a board certified radiologist or ultrasonographer to make that determination.

    [18:02]

    Treatment anti-coagulations indicated for all patients with proximal DVT, symptomatic, isolated distal DVT if the bleeding risk is low. If left untreated, one third of patients with symptomatic isolated DVT developed extension into the proximal veins, one third of the patients with symptomatic. Surveillance should be with serial ultrasound, is it getting better? Is it getting worse, right? Once they are anti-coagulated because people still can get worse even though they're anti-coagulated they should have an ultrasound within about a week or two. You're going to get with the primary care doctor to determine when or what he or she wants to do.

    Surveillance with serial ultrasound should show either that the thrombus resolves with no anti-coagulation indicated, it extends into the proximal veins and it should be continued. It extends toward, but not into the proximal veins and it's recommended that it continues or it does not extend, but does not resolve, it becomes chronic and those cases, you can just watch it. Treatment is going to depend on bleeding risk, diseases which affect the half-life of administered anti-coagulant i.e. renal failure for Lovenox. So if your Lovenox is not processing through the kidney's it's going to hang around longer, it's going to make them – it's going to damage the kidney in the first place and it's going to make the anti-coagulant affects potentiated.

    Patients with a low bleeding risk should be anti-coagulated. Patients with a high bleeding risk should not be anti-coagulation – anti-coagulated and instead get an IVC filter. So I had somebody with hemophilia, they ended up getting an IVC filter. People on dialysis, it is bad idea, it doesn't get dialyzed out pretty well. So they'll get a lot of filters, but this is where again, you want to invoke the help of this person's primary care doctor, vascular surgeon and interventional radiologist what have you. Absolutely contraindication to treatment is active bleeding, severe bleeding, platelet counts less than 50,000.

    [20:02]

    Recent planned or emergent high bleeding re-surgery, major trauma, recent history of intracranial hemorrhage, this is more for emergency situations and if somebody has a platelet count of less than 50,000 hopefully, they're not in your office. Relative contraindications, less than 100,000, these people I do see, right? Platelet count, 100,000. So the first thing I do when I suspect somebody with a DVT is I go back to their pre-operative lab values and I say, what were their platelets, where they hundred? Where they 125,000, right? So you want to be cognizant that you don't anti-coagulate somebody who has relative contraindications without recognizing the risk.

    Patients greater than 65 years old with history of multiple falls, this is where our MIPS and our MACRA comes in, right? And we documented their ability to be weight-bearing or are they dizzy? Are they unsteady on their feet, right? So if we've documented that they are unsteady on their feet and they require X, Y and Z and then we anti-coagulate them for a DVT and then they bang their head and we didn't tell them that they need to go to the emergency room if they banged their head or they fall or what have you, boy, we did that patient some harm and nobody wants to do a patient harm, right?

    Indications for anti-coagulation in asymptomatic DVT, DVT extension into or towards the proximal veins, patient at risk for extension into the proximal vein. Options for treatment are Lovenox, subcutaneous injection, oral factor X inhibitors, right, like Xarelto. Excuse me. Unfractionated heparin, again, it's not a reasonable thing to give somebody in an outpatient setting three shots of heparin a day. Warfarin cannot be administered alone with as an initial anti-coagulant. So let's just spend a minute on that because it may have been a while since you have processed this.

    [22:04]

    The Coumadin works on the extrinsic pathway, right, factors V and VII. So it takes about three days for it to bump. So for the time that you prescribed Coumadin, that person is on Coumadin is going to take about three days for them to be therapeutic. So during that period of time, they are actually majorly subtherapeutic and that DVT is going to propagate. So instead you use a short acting bridge, like low molecular weight, heparin Lovenox and you bridge them to the three days until lab value showed that the INR has come up. Conversely, if you're operating on this person that are on Coumadin or Xarelto for any matter, they're going to be hypercoagulative – hypercoagulable when you unbridge them.

    So you have to still bridge them with the Lovenox at the end as well. So it's very, very you know, it's kind of give some and take some at the same time. It's something you should feel comfortable with and certainly not defer, but be involved with the hyper – with the primary care doctor as well. Malignancy, DVT is associated with a higher morbidity. Higher rates or recurrent thrombosis and anti-coagulation associated bleeding in patients with creatinine clearance, greater than 30, low molecular weight heparin is the agent of choice. Now, let's spend a minute on that because we operate on a fair amount of people who are on dialysis or who have stage one kidney disease or what have you.

    Everybody remembers the Cockcroft-Gault equation, right? 140 minus the patient's age times their weight in kilogram divided by their creatinine, right? You want to be aware of that. It's in your med math. There're a lot of people with this score lower than 30 that were put in Lovenox in any given day. Pregnancy, low molecular weight heparin is the preferred agent because it doesn't cross the placental barrier like Warfarin does. There're been poor studies for Lovenox and unfractionated heparin, by far regular heparin is better.

    [24:07]

    Treatment, the decision is based upon the clinician's experience, the risk of bleeding patient comorbidities, cost convenience and preferences. Outpatient treatment is appropriate if the patient is hemodynamically stable. They have a low risk of bleeding, there's no renal insufficiency and they have access to outpatient monitoring and follow-up care, right? They need to go that Coumadin clip. Inpatient treatment is appropriate if they have a massive DVT, phlegmasia, which we're going to get into in a second. Concurrent or symptomatic PE and comorbid conditions or other factors that warrant in-hospital care. I always let the emergency room decide that.

    So phlegmasia cerulea dolens is an uncommon massive iliofemoral DVT, more aggressive treatment. I include this only because we had one of them so kind of scary to see this. Everybody thought man, its frost bite. It's its gangrene. It's what have you and come to find out we got a duplex, right? Because if you look, not so swollen. This is bilaterally, but not so swollen in the cath. Not so swollen that you would say that kind of looks like an ischemic leg to me with the redness. Is it cool and come to find out they had this in their artery or in their vein, right? Big, big clot from heel to heel. So direct thrombolysis are thrown back to me, IV on fraction and heparin. I have to get the surgical in there Dr. Friedberg. Thank you very much. We're a little ahead of schedule.


    TAPE ENDS [0:25:44]