Charles Anderson, MD discusses the importance of a good history and physical exam in identifying peripheral vascular disease. Dr Anderson lists tools available in vascular labs, as well as explaining major problems in patients getting appropriate treatment of peripheral vascular disease.
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Release Date: 01/14/2019 Expiration Date: 12/31/2020
Charles Andersen, MD
Chief of Vascular-Endovascular-Limb Preservation Service and Medical Director of the Wound Care Clinic at Madigan Army Medical Center
Clinical Professor of Surgery at the University of Washington and the Uniformed Services University of Health Sciences
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TAPE STARTS – [00:00]
Speaker: We started off the program -- the first talk of the program I gave was entitled a well-functioning limb preservation program is like a symphony. The concept is that to have a well-functioning limb preservation program, you have to have the right players, the right skills and working together to make great results. If you look at the summary of the meeting so far, when you look at that symphony for limb preservation, the players, key players are podiatry or podiatric surgery, vascular intervention and that can be a vascular surgeon, a cardiologist and interventional radiologist and wound care. So if we summarize what we have seen so far in the conference, we have had some very excellent lectures. When it comes to the podiatric component, we have had some good lectures on podiatric technique. We had just an outstanding lecture yesterday afternoon on the radiographic diagnosis of osteomyelitis, an outstanding lecture. When it comes to vascular, we have seen some just outstanding and almost unbelievable lectures on the current state of the art being able to revascularize down and including the arch of the foot. When it comes to wound care, which has always been a major part of this meeting, we have had some excellent talks on advanced wound care products. If you kind of big picture summarize all of those talks, we now have in our toolbox some outstanding advanced wound care products.
Over and over again through this meeting, we heard reference to the four-week reassessment initially made popular by Dr. Sheehan. The idea is that if we are not progressing in the healing of that wound, we need to back up, reassess what we are doing, make sure we have the correct diagnosis, make sure that we are treating the underlying disease and that we are using the appropriate wound care and we have heard about many advanced products that then can be an adjunct in getting those wounds to heal. We heard about topical oxygen, a very controversial subject that again some good data on the role of that may play in the future. So that's kind of a summary of where we have been so far. We are building that symphony. We are getting skills. We have the players to then practice limb preservation. So this morning, I am going to talk about the pitfalls in the diagnosis and management of PAD. So I have no disclosures. This is important that I am a vascular surgeon. I am biased. I am very, very vested in limb preservation and wound care. But important is that what I say is my opinion and not the opinion of the army, I work for the army, or the Veterans Affairs. And this presentation is not meant to endorse any products, company or program.
So our learning objectives for this morning are to discuss the importance a basic good history and physical and identifying PAD. Talk about what tools are available in the vascular lab and more importantly the limitations of those tools and then what is the major problem in getting appropriate treatment of PADs. So pitfalls in both the diagnosis and management of PAD. Big picture, there are two words here that are emphasized. The timely diagnosis and aggressive treatment of peripheral arterial disease is a critical component of a limb preservation program. I talked a little bit on Tuesday morning, or Wednesday whenever it was, about that sometimes we fail in limb preservation because the patients don't get to limb preservation program. So key is we have to also reach out to the public, make sure the public knows what limb preservation is all about. We saw a good example and a discussion in the program earlier talking about breast cancer and limb preservation. Everybody knows that if you have a breast mass, you know that's very serious. You seek immediate attention and you get the appropriate treatment and there is a good survival. What the public doesn't know is the risk of being a diabetic, the risk of a diabetic losing their extremity, the seriousness of an ulcer and the fact that they need to seek immediate attention just like breast cancer and go through the steps to have a more functional life to control the diabetes and hopefully prevent amputation.
So the timely diagnosis, aggressive treatment of peripheral arterial disease is a critical component of limb preservation program. Sometimes the diagnosis of PAD is very easy and good history and physical. At times, the diagnosis is very subtle and at times as we heard yesterday with a couple of very good lectures on the treatment of PAD that PAD can be very silent. So you can have limb threatening critical limb ischemia or you can have a wound that's not healing that has severe PAD and they don’t have classic symptoms of PAD. So the concept of silent PAD becomes very, very important when you are talking about the diagnosis of PAD. So when you look at this patient, it's obvious that this patient has PAD. You see the dry gangrene of the toes, the secondary changes of PAD. This is a patient, no wounds, but has ischemic rest pain and what you see here is the dependent rubor. If you are to put this extremity up, it would be pallor on elevation. So again, fairly easy diagnosis of significant PAD. The history can indeed be important especially in the early stages of PAD. Many times in our practice, we will have people complaining of leg pain, foot pain and the challenges, how do you differentiate musculoskeletal pain from vascular pain or claudication, and again sometimes claudication is not classic claudication.
In the history we go back to what's called Warren's criteria. That's three things that you look for on a history to make the diagnosis of PAD or a diagnosis of claudication. That's pain on exertion, patients walk at certain distance, they get pain and they stop walking. Relieved by rest, those patients just stop walking, the pain goes away very promptly and the third one is reproducible and consistent. In your practice, this last Warren's criteria can be very, very helpful in sorting out musculoskeletal type of pain from true vascular claudication. That consistency the fact that they don't have good days or bad days, it doesn't vary during the day. But every time they try to walk, they get that pain with walking. Rest pain, oftentimes we get referrals for people that are having cramps and the diagnosis is ischemic rest pain. Ischemic rest pain is something very specific. It's not pain in the muscles of calf, it's pain in the foot across the metatarsal heads. The classic history of ischemic rest pain is that patients develop their pain when they go to bed. The reason as they lose the positive effect of gravity. They develop their pain and they find that if they hang their feet over the side of the bed, the pain is relieved. That's a good history for ischemic rest pain. So when we talk about the diabetic patients and many times when we are talking about limb preservation, we are talking about patients with diabetes. It makes the diagnosis of PAD even more of a challenge.
Many times because of neuropathy or again lack of activity, these patients do not have typical symptoms of claudication and they may not have ischemic rest pain. It's very important to look in the patient with diabetes to identify that disease early. It's not because they need a loop reconstruction of the arch of the foot, it's because if you identify that PAD early, you can treat that systemic disease and change the course of atherosclerosis, which is the systemic disease. In addition, if you are a podiatric surgeon or any surgeon that's doing a vascular procedure on the foot or ankle, to not recognize vascular disease then sets a stage for complication. In addition to that, making the diagnosis of PAD in the diabetic patient that may be undergoing another procedure tells you that these patients have a systemic disease and that systemic disease also involves the coronaries or the carotid arteries. So it puts those patients at risk for a perioperative MI and stroke. Again perioperative management, which I will talk about a little later this morning, is critical in these patients with diabetes. Pulses, my residences can feel a pulse in anybody. So you have to really know whether or not you can clearly palpate pulses. If you are there wondering or feeling your own pulses in your fingertips, that's the patient needs an additional assessment. Capillary refill time is something that's still taught in school. When you are dealing with severe PAD, that's a very worthless and a misleading test.
So when you have that dependent rubor, for example, you push on that foot, you are going to get an immediate return of color that has nothing to do with the circulation time, that stasis. The red foot is very useful not only in vascular disease but when you are seeing that patient in the emergency room and the question is, does that patient have cellulitis? A simple very simple test in all of those patients is to elevate the extremity. If that erythema goes away, it may be vascular disease, it may just be stasis but if the erythema goes away, it's not cellulitis. So I mentioned screening for PAD, it's really not about the legs, although if they have a wound, it's certainly about the legs but it's to just identify the systemic disease. The ADA recommends screening the patients over the age of 50 with diabetes with an ABI. Again, we heard about this earlier in this program that can be important in identifying those patients. Once we know they have PAD and we know the degree of PAD, then good preventative care or early intervention can be appropriate. For example, if you have somebody with severe PAD and they don't have a wound, that's an ideal time to intervene because intervention can be a simpler intervention than having to go all the way down to the foot to restore flow to the toes. Pre-op screening, again I have already mentioned but very important.
It's important to understand the role of PAD. So I called this cause and effect. When you look at the picture on my left, that's typical PAD that's led to gangrene. The picture on the right, you see the toes look well perfused but this patient has an ulcer and this patient has coexisting vascular disease. That vascular disease did not cause that ulcer but now that you have that ulcer and you have associated vascular disease that plays a major role in whether or not that ulcer will be able to heal. So many times PAD associated with diabetic foot ulcers but not that direct cause of diabetic foot ulcers. So we all know that a diabetic foot ulcer in general occurs in a patient with neuropathy, altered biomechanics and repetitive oftentimes unrecognized trauma that then leads to that ulceration. The confounding factors that oftentimes then lead to the risk of amputation are once you have that ulceration, then if you get infection or you have associated vascular disease, that's the trigger then in these patients that can take you to a higher risk for amputation. I have a great partner, a very talented podiatric surgeon, Dr. Mario Ponticello trained at Georgetown. And he takes part in a regional MNM conference, so the podiatric training programs in the Seattle area get together and they discuss cases. He came back to me after one of the MNM conferences and he said failure to identify vascular disease preoperatively may lead to significant problems and in that particular MNM, that was the most common cause of the postoperative complications that were presented that day.
We call this tipping the balance. If you have somebody with unrecognized PAD and you do a procedure, that procedure may not heal. So this is -- you see the balance -- what happens is you can maintain intact skin with a low level of perfusion but as soon as you do an operation or you develop a wound, the demand goes up. If you can't meet that demand with the appropriate supply, then that leads to failure to heal. So this was a truck driver. He had pain when he was driving his truck, pain down in his toe. So he stopped at Doc-In-The-Box. And he went in and the doctor there said, well, you are having pain in your hallux and your big toe, I think it's a paronychial problem. He proceeded to do a very minor procedure if you will in the Doc-In-The-Box Clinic and by the time he got to us, as you can see, he had gangrene or had dry eschar and gangrene of the tip of his hallux. His pain was ischemic rest pain. It wasn't the paronychial problem. So again the key is if you are planning even a minor operation on the foot, make sure that that patient is well perfused. I mentioned this quote by my partner, Dr. Ponticello. So when we look at physiologic testing, everybody knows what an ABI is. But many times an ABI can be very misleading.
First of all, an ABI measures the pressure where the cuff is, not where you're listening with the Doppler. So you are measuring the pressure needed to occlude the artery at the ankle. So you are measuring an ankle pressure not a foot pressure. A simple test to learn in everybody, in my opinion, everybody in their clinic should have a Doppler. Doppler is something that can be very useful in just part of the physical exam in your clinic when you are trying to evaluate whether or not patients have arterial disease. If you are unsure about the pulses, it's very easy to grab that Doppler and listen to the Doppler signal in the dorsalis pedis, posterior tib and peroneal arteries. A normal Doppler signal is triphasic, so it sounds pchifu, pchifu, pchifu [phonetic]. As disease progresses, you lose that third sound, so it becomes biphasic pichu, pichu [phonetic]. And then if disease progresses, it moves towards monophasic pfoo, pfoo [phonetic]. So just listening with the simple Doppler can be very, very important, very useful and it's really an extension of the physical exam. ABIs, when you look at what the numbers mean, an ABI again measuring pressure at the ankle. A normal ABI is 0.9 or above, generally thought of somewhere between 1 and 1.2. The key is an ABI can be falsely elevated because of calcification in those vessels of the ankle.
That may give you an ABI of 1.4 or non-compressible ABI, but also you can have an ABI of 0.9. That is a marker for very severe disease because vessels are just poorly compressible. So when you are looking at an ABI result, you should also assure that they have waveforms that you can look at. So a normal ABI number with a triphasic waveform tells you that the flow is normal or that the arterial signal is normal. The Doppler, although the Doppler is not a flow meter, it's a velocity detector, is normal at the ankle. An ABI of 0.6 generally indicates that you may have a problem with healing. A good number to remember is an ABI of 0.5 or less. When you get below 0.5, almost always you have multilevel disease and when you get down around 0.3, that's when you start seeing ischemic rest pain. So this is a typical report that we put out on our lab. You see the numbers but you also see the waveforms. So although this patient has numbers that look fairly normal or elevated, you see the waveforms are very abnormal and this patient turned out to have very significant distal vascular disease. An important concept and we heard a lot about this in the past couple of days when we were hearing the lectures about the advanced techniques of revascularization. Now, it's important to understand not just what's going on at the ankle but what's going on in the foot and oftentimes we have regional malperfusion within the foot that the ABI will not pick up.
This is a patient that had a previous bypass to the posterior tibial artery. You can see the bypass is patent down to very fine collaterals in the foot, amazing, it's a vein bypass. ABI was 1 but obviously doesn't pick up the fact that there is very limited flow in that foot. Regional malperfusion is demonstrated here with DSA arteriogram in the foot, can have a significant impact when you are doing procedures in the foot like TMA. Again, you see there is flow, good perfusion in the posterior tib but the dorsalis pedis is isolated, not a direct line flow into the dorsalis peids and the distal part of that vessel is not perfusing at all. Toe pressures can be more useful in the patient with diabetes and generally the toe arteries are not affected by calcification. So the toe arteries and the TBI are better indication of perfusion in the patient with diabetes. A normal TBI is 0.75. When you get TBI of less than 0.25, that's severe disease. An absolute pressure of 0.55 generally correlates with the ability if it's greater than 0.55, the ability to heal. Segmental pressures that's put in cuffs, three or four cuffs positioned along the lower extremity and then you measure pressure at the thigh above the knee, below the knee and ankle and you look for a gradient between those cuffs. So that can help you determine where the disease is or you see that gradient is then where the disease is.
Tissue perfusion is something that especially now that we have the capabilities of understanding regional malperfusion and we have the ability to treat regional malperfusion in the foot, that looking at tissue perfusion becomes very, very critical and there again some -- when you visit the vendors, there are some modalities that can aid you in measuring tissue perfusion. So when you measure tissue perfusion, it can help some key questions. Is there a need for revascularization in the specific part of the foot, for example, and once revascularization is accomplished, has it been successful? Is there adequate perfusion to heal a reconstructive procedure or heal an ulcer? Is debridement required and can you then assure that there has been adequate debridement, i.e., following debridement you have good perfusion to that wound bed? So measurements of tissue perfusion can be very helpful. This is the traditional ways we have measured tissue perfusion. TcPO2 in our lab was used previously. It's cumbersome oftentimes not reproducible and the problem is where you want to get the pressure, many times you can't get the pressure there because it's over a bony prominence or there is a wound. Although TcPO2 is useful in looking at tissue perfusion, it does not give you that global picture of tissue perfusion. So the current methods that we have traditionally used have some significant limitations. We are now dependent on a technique of fluorescence angiography that entails injecting indocyanine green and IV injection and then looking at tissue perfusion in the foot.
What that gives you is a global picture of perfusion in that foot so that you can identify regional malperfusion. So we used it again to look pre and post intervention whether or not we have accomplished what we were trying to do. We also used it in the session on the amputation on Saturday. I will give a talk about how we use fluorescence angiography in the operating room. We use it very extensively to evaluate the tissue perfusion anytime we create a flap and make sure that flap is well perfused. We then close the flap, re-measure tissue perfusion to make sure that suture line is well perfused. If it's not, we modify that before we leave the operating room, so that once we leave that operating room, we know that suture line is well perfused and that has led to a marked decrease in our incidence of suture line complications. So this is just an example of pre-arteriography. Post-arteriography, again it's hard to measure that with even toe pressures, this gives you the global picture. You can see that there is still an area of ischemia, so we would call our friends from yesterday if there was a wound there, then try to reconstruct the pedal arch, right Bob? Right, so pre-amputation, this patient had disease and infection that we felt was not re-constructible. The patient went for an elective BK amputation and this just shows the kind of studies that we do in the operating room.
Orphan heel syndrome is a good example of regional malperfusion. The heel has a watershed area, so there are branches from the posterior tibial, peroneal artery that supply the heel but sometimes the heel can be ischemic even when you have a palpable dorsalis pedis pulse for example. So it's looked as an orphan area, hence the orphan heel syndrome. So we know heel ulcers are common but I think what we have not recognized in the past as many times regional ischemia is a contributing factor of why those heel ulcers don't go on and heal. Interestingly enough although in this conference, we spend a lot of time looking at the traditional diabetic foot ulcers. Heel ulcers have higher amputation rate than do forefoot ulcerations. So it's an area that, I think, has people involved in limb preservation, we need to know a lot more about heel ulcers. So this is simple case, an elderly patient that had an ulcer, came in. She did have evidence in the vascular lab and on physical exam of arterial disease but that didn't really quantitate what was going on in the area of the heel. So you look at the ulceration kind of a dry ulceration than look real ischemic. So this is our first fluorescence angiogram. What you see is severe ischemia in the wound. So we heard several people over the past couple of days talk about ischemia, focal ischemia in a wound. I think that's a very, very important concept.
Even at times when we have intact macrovascular disease, we can have focal ischemia in a wound and for example when we were talking yesterday about the potential benefits of oxygen therapy that may be an area where if you have focal ischemia of the wound that could play a role. Here, you see a blotchy distribution of perfusion of the heel but no perfusion in the area of the wound. Again, this is a color rendition of the same with the blue being poor perfusion of the heel. This patient had an arteriogram performed, was found to have significant popliteal disease, tibial disease that was treated with stent and distal angioplasty. And here you can see the pre and post stenting of the popliteal and angioplasty of the tibial vessels. This ulcer was then debrided. Now, we do a study to see if we have accomplished what we needed to accomplish. So now you see excellent perfusion of that heel and that patient then went on to completely heal the heel ulcer in six weeks. So regional malperfusion, the idea that the traditional studies that we use in the vascular lab may not be able to pick up the regional malperfusion. More important now because we have the tools that can treat that regional malperfusion and again prevent amputation. Duplex scanning can be an important adjunct in planning and intervention.
Duplex scan gives you the ability to look at an image, the B-modes so you can actually look the artery and then with the Doppler part of the Duplex scan, you can look at the velocity either through or around that area so you can distinguish between, for example, a total occlusion or stenosis. So it's useful in providing more information about the arterial disease, which can then be very useful in planning an intervention. This is looking at the ability of Duplex scanning to pick up aortoiliac disease. So our technicians and hopefully your technicians become very facile in looking at the aorta or aneurysm for example but also looking at iliac disease and identifying areas of stenosis or identifying that it's not just a stenosis but that's a total occlusion. That information then becomes very, very useful in planning your intervention to restore flow in the aortoiliac system. Likewise in the infrainguinal area, if you can distinguish a stenosis from a total occlusion and you can see the length of that total occlusion for example, if you identify in your initial assessment that this patient has total occlusion of the SFA, total occlusion of the popliteal artery and they have distal tibial disease and you can see all of that with the Duplex scan. Then that tells you the kind of intervention that's going to be required, either a distal bypass or an endovascular intervention that's going to entail infrapopliteal interventions.
MRI can be useful. It depends on the hospital. You can get sometimes signal dropout and get some false information but we still use that on occasion. We rely a lot on CT arteriography. The nice thing about the CT arteriogram is what the software that is now available. You can take these images and you can play with the images. What I mean by that is you have 3D images, you can spin those images. When we are doing an aneurysm repair for example, you take all of your measurements for the endograft, the graft that's going to be placed inside the aneurysm, all of those measurements were obtained with the CTA. There is now software that you can use the CTA, you can actually then use 3D and we heard about this in the diabetic foot, you can use 3D reconstruction, you can actually make a graft that has branches and it has holes for arteries, all of that's done using the information from the CT arteriogram. The downside of CT arteriogram especially in limb salvage and patients with diabetes is significant contrast load and at times that can tip those patients over into renal failure or certainly have an impact on their preexisting renal failure. The standard DSA or arteriogram is the gold standard and as we saw on the cases of the past couple of days, you can image down to include the foot, the vessels and the toes and you can then use that information to do very distal revascularization.
So what are the pitfalls now that you have made the diagnosis in treating PAD? The biggest pitfall is to assume the patient does not have revascularization option. If you have attended the whole conference, I think one of the things that you will leave here with is the knowledge that the majority of these patients even if you are dealing with very, very distal tibial disease or disease down in the foot, that this now has become a new standard, that these patients can be treated. So we don't want to ride off patients because they are diabetic, because they have small vessel disease. Diabetes have macrovascular disease and microvascular dysfunction is totally different. The majority of patients with diabetes can be re-vascularized. The major problem is when it comes to treatment, if we don't make the diagnosis, you don't treat. So again, recognizing silent disease using the appropriate treatment or the appropriate diagnostic modalities to identify that silent disease. Assumption that there are no options, too many amputations in this country are performed without even a vascular consult, without even ABIs and without an arteriogram and without any attempt at revascularization. Unfortunately, that still is a major problem in the United States. Lack of diagnosis, assumption there are no options and the third one we started out talking about the symphony.
We talked about the players. When it comes to the vascular component of limb preservation, you need a provider with the appropriate skills, with a passion and persistence to get revascularization down to and including the foot. I am a vascular surgeon and when I first started talking at this meeting, I think, 10 years ago, I was pretty biased towards vascular surgery. It has become very, very obvious now that we have some very, very excellent interventional cardiologist, some very excellent radiologist and some very excellent vascular surgeons, all if they have these skills, if they have the passion and they have the desire, they can revascularize these patients down to the foot. So it requires very advanced endovascular skills that can extend revascularization down into the pedal arch. Pitfalls are inadequate revascularization. So you're still going to see somebody that has multilevel disease as a significant wound on their foot and they have, let's say, common femoral endarterectomy performed or may be treatment of the SFA. In some patients, that's adequate. In other patients where there is distal tibial disease, it's not adequate. So you need to make sure that you are working with the right interventionist and that you continually come back to the huddle. So if you take a patient that you are following the patient has a wound, you sent that patient to have a vascular assessment and revascularization and the patient then comes back.
You are following that patient for a while. The wound just isn't progressing. You need to then go back to your interventionist and say we need to reassess. So you repeat the vascular studies. You repeat the assessment and that patient may require an additional revascularization procedure to go even more distal to get that wound to heal. The other thing is that as you heard in the past two days when we are doing distal revascularization down to and including the arch of the foot that those vessels oftentimes don't stay open very long. If you are fortunate, you have the restoration of flow, you are able to get that wound healed while that flow is present. But at times what happens especially with the endovascular procedures is that you will have an initial patency and then you will have thrombosis of that endovascular procedure. So again coming back to that huddle with the wound care, podiatric surgery, vascular surgery and saying that wound was doing pretty well for a month, we made great progress in the past two weeks. Not only has it stopped progressing, it has gotten worse. You re-engage your vascular studies. You re-engage your interventionist and oftentimes additional procedure can be done to get that patient back on the healing pathway. Every attempt should be made as we heard again in the past two days to get direct in-line flow to the angiosome involved with the wound.
And it doesn't tail very advanced skills. When we were talking about pitfalls and revascularization, beware of the following statements. The patient is a diabetic, has microvascular disease and is not a candidate for revascularization, unfortunately still a common belief among some of our internal medicine or family practice physicians. Diabetics, as I have said, have macrovascular disease, microvascular dysfunction and almost all always can be revascularized. There is no distal target. Again, you saw some beautiful cases yesterday, the day before. It just means you haven't identified the target. So you need that detailed DSA arteriogram flows into with good visualization, the vessels in the foot and the ability to get down and get those pedal vessels open again. We have done everything that can be done. Maybe it's time for a new interventionlist. The patient will end up with an amputation anyway. We have talked about that in great detail over the past few days that the consequences of an amputation are major in terms of not only limb loss but modification of life and life lost. Pedal bypass certainly is still an option. The key is that endovascular intervention into the foot or pedal bypass, one or the other, has now become the standard. For those patients that have distal disease, they oftentimes need that direct in-line flow to the foot.
It's important, once you have done the intervention, to monitor that intervention, especially if you have done an open vein bypass. Those vein bypasses can identify or can develop areas of stenosis. If you identify that area of stenosis before that vein graft completely occludes, that's a salvageable vein graft oftentimes with an endovascular procedure and the secondary patency is as good as the primary patency. Likewise, I have mentioned if the patient stops progressing re-evaluate, re-engage, come back to the huddle, the limb preservation huddle, and have constant communication. Again, we started this morning with the symphony. Podiatric surgery, vascular surgery, wound care come into that huddle, what more can be done for limb salvage. There are still a few patients that we cannot revascularize. This is another option that we have used. The Ardisist [phonetic] there is a booth outside again. I have no vested interest. Only we have had some good experience using compressive therapy. These patients treat themselves for an hour generally two or three times a day. We have been able to heal wounds that we could not reconstruct their vascular channels and we have been able to demonstrate again using fluorescence angiography, the fact that this top picture is prior to treatment. After one hour of treatment with fluorescence angiography, you see that there is very enhanced skin perfusion after just a single treatment. So that's another option if you run out of direct revascularization options. So in conclusion, the biggest pitfall in the diagnosis of PAD is not looking for the disease.
Not recognizing that silent disease. The next pitfall is not understanding the limitations of the non-invasive vascular studies and we have gone through the limitations, especially of an ABI. The third is to not recognize that there can be regional malperfusion to an area of the wound or in the foot that will not be picked up the standard non-invasive vascular studies and enhance imaging studies or even an advanced arteriogram with fuse down to the foot can identify and set the stage for treatment of that distal disease. The biggest pitfall in the treatment is failure to treat. If you don't evaluate and you don't treat, that's a failure of treatment or inadequate treatment again not having the correct player with the skills to extend that revascularization down to and include the vessels within the foot. These are the references. We have two minutes and one second for question.
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