Board Review Vascular

Arterial Disease in the Diabetic Lower Extremity: Current Options for Management

Charles Andersen, MD

Charles Andersen, MD discusses aspects of peripheral artery disease, limb ischemia, and limb and life preservation. Dr Andersen reviews revascularization, timing, techniques and outcomes.

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Goals and Objectives
  1. Describe the role of screening for Peripheral Arterial Disease (PAD)
  2. Discuss indications and timing for revascularization
  3. Analyze the role of endovascular therapy versus open revascularization
  4. Discuss regional perfusion of the foot
  5. Discuss the outcomes of revascularization and describe the role of surveillance
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  • CPME (Credits: 0.75)

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    PRESENT eLearning Systems, LLC has approved this activity for a maximum of 0.75 continuing education contact hours.

    Release Date: 03/16/2018 Expiration Date: 12/31/2018

  • Author
  • Charles Andersen, MD

    Chief of Vascular/Endovascular/Limb Preservation Service and Medical Director of the Wound Care Clinic at Madigan Army Medical Center<br /> Tacoma, Washington<br /> Clinical Professor of Surgery at the University of Washington and the Uniformed Services University of Health Sciences.

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    Charles Andersen has disclosed that he is a consultant/advisor for KCI, Organogenesis and Spiracur

  • Lecture Transcript
  • Male Speaker: I’m not sure how I got on Dr. Freiburg’s [phonetic] bad side. But obviously he’s given me some interesting assignments including 6:00 in the morning. When I asked him about the 6:00 lectures, and he did the one yesterday, he said it was because he needed to reach a certain number of GME credits and to do that it require the 6:00 lecture. I appreciate those of you that have come out so early. And we’ll see if we can touch on some new things, one that has to do with arterial disease. Obviously the people that are here for this conference are passionate about podiatric surgery, limb preservation, prevention of amputations in the patients with diabetes. To just kind of set the stage, which I think is obvious to all of us but just to reiterate it, that when you talk about limb preservation in the patients with diabetes, certainly the timely assessment and appropriate treatment of vascular disease is critical to limb preservation. Disclosure is really nothing having to do with this lecture, perhaps a bias. I am a vascular surgeon with a very strong interest in limb preservation. So, I’m passionate and I’m biased. Certainly the opinions that I present this morning are my opinions not the opinion of the US government or the opinions of Madigan Army Medical Center where I work. I’ll go through a number of products having to do with mainly endovascular intervention. It’s not meant to promote any product but more of the concepts that these products represent. Our learning objectives are our goals are described, the role of screening for PAD, discuss the indications for revascularization, analyze the role of endovascular treatment versus open revascularization, discuss regional perfusion of the foot, something that I think more and more we are realizing the importance of that, discuss the outcomes of revascularization and describe the role of surveillance. So again big picture, very important in limb preservation. Some key questions when you think of arterial disease in the patient with diabetes. Does the patient have arterial disease? Does the patient require revascularization? When should revascularization be done? The whole question of timing, which I think is very important. What treatments and what happens after revascularization? So the ADA has recommended the screening of patients over the age of 50 with diabetes with ABI, and certainly abnormally ABI can be an indicator PAD. But perhaps more importantly when you’re thinking of screening, if you have abnormal ABI you have a disease, and the disease is atherosclerosis. In my practice when we’re talking with the residences we make rounds and we’re treating patients with significant arterial disease. The point is that has the CAD progresses, so that you have a parallel line, when patients have critical limb ischemia, more times than not they have a component of critical coronary ischemia which makes these patients at high risk for mortality from their myocardial infarction. Early screening and looking for disease early can then identify patients with atherosclerosis, and then you can be more aggressive in treating the atherosclerosis. The point is if you have an abnormal ABI, everybody needs to be treated but not treated with endovascular intervention or bypass. What they need to be treated for is their systemic atherosclerosis. And there is an involving literature that demonstrates early recognition of atherosclerosis [Coughs], excuse me and modification of risk factors can then decrease the major morbidity and mortality associated with atherosclerosis that being MI and stroke. The other thing, as we prepare for example the due complex podiatric surgery, if we identify a patient that has an abnormal ABI.


    That not only is important that may affect the healing capacity of that operative side but the other thing it indicates is they may be at increased risk for an operative procedure. Again, going back if you have PAD, you have CAD, therefore, you’re at higher risk for a perioperative myocardial infarction. So, flyers like this, why is my doctor getting an EKG, I have pain in my leg? And again, it just speaks to the association of PAD and CAD, ao all patients with PAD should at least be on medical management for their atherosclerosis. One of the misconceptions, especially when we start teaching our medical students for example, our medical students and sometimes our residents get the opinion that if you have PAD, that that’s a disease that always progressives, progressive from claudication to limb threatening ischemia and on to the potential for amputation. Actually, the natural history of PAD is pretty benign in most patient. So if you take claudicators and this is some very early study by Dr. Boyd [phonetic] has been repeated by Dr. Darly [phonetic] and Dr. Crowninroth [phonetic]. There are several other more recent studies but what it demonstrates is when you have a patient with claudication and you follow that patient for five years, for example, only 7% go on to limb threatening ischemia. At 10 years, it’s still only 10%. So, the point is and it gets back to the treatment of patients with claudication, you can’t tell these patients, you shouldn’t tell this patient, “You have claudication, we better hurry and treat you, for example, with an endovascular intervention before you get to the point of limb threatening ischemia.” The point is the majority of these patients do not progress on threatening ischemia. It doesn’t mean they don’t need their atherosclerosis treated but they don’t need an intervention on their claudication unless it’s lifestyle limiting claudication and really something that they desire to be treated for. When we look at claudication then, again realizing the natural history of claudication, when we’re thinking of intervention for claudication not limb threatening ischemia but intervention for claudication, we should be thinking of procedures that are very durable. So still a significant role in my opinion for bypass versus endovascular procedures in patients with claudication. We know that those patients, those procedures are very durable and can give long-term results and we’ll get into to some large studies that have demonstrated that. So, certainly that subcategory of patients that progress on to limb threatening ischemia or those patients with diabetes that you see that have a wound and have associated arterial insufficiency, those patient require revascularization to prevent amputations. So that’s a subset. An important thing to realize and it gets into the timing of intervention for atherosclerotic vascular disease is if you take a patient with diabetes and you look at the flow that’s required to maintain intact skin you can have very limited flow. And if you don’t have a wound, you can maintain intact skin. The problem is once you create a wound and the larger the wound the more demand, but once you create a wound what that does is increase the demand for flow. So that can now change the picture. So, now you have a patient that previously had a component of atherosclerotic vascular disease, maybe or maybe not had claudication but now they have a wound and that underline atherosclerotic disease will then become a limiting factor as to whether or not that patient is able to heal a wound. So the balance shifts. Therefore, in patients, all patients with diabetes as Dr. Freiburg mentioned yesterday and other people have mentioned certainly prevention of wounds is critical. If the patient has atherosclerosis and you can prevent them from giving a wound many times you can decrease the need for revascularization even if they have underlying arterial disease.


    Patients with limb threatening ischemia certainly should all be evaluated to see if they’re candidates for revascularization. And you should look around the country and there are still centers, there are still areas where patients will develop an ulcer, develop significant problems with their feet as far as wounds and end up with a major amputation, a BKA or an AK amputation without ever having an arteriogram. I think, again at the onset I said I’m very opinionated and biased. I think that’s an error that even if the patient already has a significant ulceration, if you can restore flow to that patient and then do a limited procedure in the foot versus a AK or BK amputation, it’s much more likely that that patient will continue as a functional individual. So, not only revascularization to heal wounds but sometimes with more extensive disease, revascularization to keep the level of amputation as low as possible. The question of endovascular versus operative intervention is a very interesting evolution in vascular surgery. Patients, as I mentioned, that have critical limb ischemia oftentimes have critical coronary ischemia. Because of that, the perioperative risk is significant. Also, these patients with PAD may have the inability to heal wounds. So, if you do a long incision, let’s say for a distal bypass, it’s possible that you create another wound. So with those two factors, the overall level of atherosclerotic disease, in particular coronary artery disease and the fear that they may not do well with a large open procedure, this is lead to the endovascular philosophy as endovascular first and then you list patients. Endovascular intervention is something that in general is done overnight stay, sometimes even as an outpatient procedure. I would encourage all of you that haven’t looked at the posters to look at all of the posters. There are some couple of industry sponsored posters that talked about revascularization techniques performed in the outpatient office setting which again is a new philosophy. But, again, speaks to the endovascular first and the ability to do these procedures with limited period procedure risk as far as physiologic risk to these patients. So what this has created is what I refer to as the endovascular revolution. I was just talking with another vascular surgeon in the audio but what has happened is the vascular surgeons that are coming out of training now are highly skilled endovascular technicians. It doesn’t mean they don’t do open surgery too, but they have a set of skills that makes endovascular intervention something that is very easy. Its part of there bag if you will, it’s part of the training that they have had. So, more training in the endovascular intervention. But the other thing that’s occurred is new tools. Lots of tools, some borrowed from the cardiologist that utilized these tools for coronary intervention but many tools that have been developed specifically for peripheral arterial disease. So, more skills and more tools. When you look at the number of tools or the type of tools, we’ll run through some of those. Again, many have been borrowed from the cardiologist. Balloon angioplasty is something that we’re all very familiar with. And sometimes, just balloon angioplasty without stenting is the appropriate option.


    We have a patient that was just in the hospital, a very elderly patient came in with severe risk pain. Said she couldn’t live with this wrist pain. Very committed to trying to live despite the fact that she was very elderly. We were able to treat her which is balloon angioplasty of multiple segments which she was able to then relieve her wrist pain. Cryoplasty, the concept is that it’s a cold balloon if you will and the concept is by freezing that tissue you can decrease the incidents of intimal hyperplasia. Intimal hyperplasia is the main problem for both endovascular intervention as well as operative intervention. A clot cutting balloon, so if you have an area of tight stenosis especially in an area where there’s been previous intervention, the ability to cut that tissue and then do a balloon angioplasty, again, it has been a new addition to the tools of the interval. All kinds of stents and an evolution in the types of stents, some of the older stents break [Coughs], excuse me, for example, one of the problems was fracture of the stents now as stents that evolve, the stents are able are able to go even to a right angle without fracturing of the stents of an evolution in stents, an evolution and now leading to covered stents or drug eluding stents on which all have the potential to increase in patency in the patients that are being treated endovascularly. Nitinol stents, an interesting technology. So, this is a stent that once it is exposed to body temperature then expands to the size of the artery that you’re treating. Regulating stents have been used more in the coronary arteries, some very good literature now coming mainly out of Europe that shows some advantage of drug eluding stents, mainly in the very distal tibial vessels when you’re treating these patients for limb threatening ischemia. One of the interesting concepts now is that we know that one of the materials used for bypass grafts was PTFE, the same materials that’s in your Gore-Tex rain suit, for example. Now we have very long covered stents. And in essence you can create a PTFE bypass from within the artery. So I went to presentation very recently where a surgeon was talking about actually doing an aortoiliac or aortofemoral actually taking it down to the common femoral, aortofemoral bypass and then adding a Fem-Pop bypass, all done from inside artery with access in the common femoral. So the dilatation of the disease in the aortoiliac system putting in a covered stent so you’ve created a PTFE bypass from the aorta to the femoral. Then doing intervention distally, getting through the obstruction or the stenotic lesions, putting in another covered PTFE stent and then doing an anastomosis in the femoral area so you preserve flow to the profonda. So, a completely endovascular bypass as far as aorta-femoral and Fem-Pop but then suturing the ends of that covered stent to the orifice of the superficial femoral and the common femoral, again, many times also with the addition of a common femoral endarterectomy. So kind of hybrid approaches if you will to disease using the covered stents. And some evolving literature, again not meant to support any product but now some patency studies that indicate that these even very long covered stents at good patency at even to five years.


    Lasers played a role. One of the problems is if you have a very tight area of stenosis or an occlusion, to treat that you have to get through the lesion and the laser therapy has now allowed a burrowing, if you will, or creating a channel through very tight areas of stenosis or occlusion then followed by an angioplasty or stent. And, again, I mentioned the posters, a specific type of therapy now that is done as an outpatient therapy. So, various kinds of laser atherectomies and evolving technology that is now available with minimal physiologic insult to the patient. It used to be that if you had a totally occluded artery, then this was a patient that required intervention from using open technology. Now, with specific catheters, was called re-entry devices doing sub ended tissue of a plane. Most of the time even with a total occlusion, you’re able to get a wire, a catheter through the area of total occlusion. Go ahead and treat the total occlusion and reestablish patency. So, total occlusion is no longer a block or a contraindication to treating the disease from an endovascular perspective. So, subintimal angioplasty and re-entry devices have really changed this whole field. The re-entry devices allows you’re in a outside of the lumen to visualize the lumen and then push back into the distal lumen. A very innovative technology that supports treatment of total occlusion. The other new technology or evolving skills if you will is if you cannot get through the disease going integrate, then there’s now centers that are becoming very good at pedal access and there’s again the technology that now supports that so you go down to the arteries in the foot whether it’s the dorsalis pedis or posterior tibial artery or even peroneal artery and you enter the artery from below. Now you have a catheter from above, a catheter from below trying to meet in the middle and then you can grab your catheter, pull through the entire area and treat the area. A recent addition to that is, if there’s an area of total occlusion that you can’t get through to actually go outside the artery. Come back in the artery at a different level and then put a covered stent. So in essence, you’re creating a new artery in a plane outside of the existing artery. So, evolving the tools, evolving technique. So on the open surgical bypass and the pass towards the gold standard, I think for patients with severe limb threatening ischemia it is still a very good operation and oftentimes the operation of choice if endovascular therapy cannot get pulsatile flow to the area of the involved tissue lost in the foot. Open surgical bypass known good durable results, critical component and now an evolving recognition of the importance of the angiosome concept were regional flow. A statement was made yesterday. It was made in reference to a paper by George Andrews [phonetic], some early paper that even palpable pulses in the patients with diabetes does not mean that they have adequate regional flow to the area where there may be an alteration. For example, you can have a palpable dorsalis pedis but a very poor flow to the posterior aspect of the foot and that patient may be helped with an appropriate endovascular procedure where a bypass to restore direct in line flow to the posterior part of the foot in order to get a healed ulcer or a posterior wound healed.


    So, regional blood flow very important. And what that means is in order to identify tools where you can see flow, them too, and including the pedal flow within the foot. What should we do? How far distal? This is where timing becomes very important. If you have a patient that has multiple levels of disease and when you’re speaking about limb threatening ischemia, usually you have at least two levels of disease. If that patient has multiple levels of disease, but they do not have tissue breakdown many times just treating the more proximal area of disease, for example, the aortoiliac system will restore adequate flow so that they no longer have rest pain, they have intact skin, and they can maintain intact skin. If you progress to the point that you have a wound, unfortunately it changes the plan and most times if you have a significant wound, in order to get that wound healed, then you have to go distal and you have to get pulsatile flow to that foot in order to get that wound to heal. So timing is critical. Those patients that come to your clinic that have rest pain, intact skin, they should be treated very early before they develop their wound. So when that patient shows up to the limb preservation clinic, the podiatric surgical clinic, key is to do everything you can to prevent ulceration while they’re waiting for their revascularization because it may impact what the vascular interventionist has to do. Reemphasis again on regional perfusion, you can have a normal ABI, you can have a palpable dorsalis pedis pulse and still have inadequate flow to a portion of the foot. Again, inadequate flow can be very important when you’re planning, for example, a DMA [phonetic] as you see here. You need the appropriate studies to ascertain flow to that area where you’re doing your operative procedure. Likewise, you need to make sure as you are able to identify which arteries, which collaterals are patent that when you’re doing your operative procedure you don’t interrupt those very important collaterals. One of the pictures that you’ll see all the time when you have the discussion about endovascular versus open procedures, the endovascular technician or the endovascular therapist will show a picture of a leg completely flagged so that there’s an incision all the way from the groin down to the lower part of the calf, the legs all open and the comment is, “Would you do this to your patient?” And as I mentioned early, one of the fears is when you create those long incisions that they may not heal and you end up with significant surgical site problems. One of the newer developments to decrease the incidents of surgical side infections is the introduction of negative pressure therapy over closed incisions. So, no wound. You close the incision but you put negative pressure therapy over the top of that incision. This is fairly a recent paper, again showing the advantage of closed incisional negative pressure therapy in patients undergoing vascular procedures. The sology classification of wound problems. Sology one means that the skin or subcutaneous tissue is involved. Sology two, deeper involvement than that involved in the graft. Sology three means that now the surgical site complication extends down to the graft which may lead then to significant problems including the need to remove that graft, thrombosis of the graph, amputation, and even death. So that preventing a sology three, a complication associated with a vascular anastomosis is critical.


    So when the study from LSU looked at the incisional therapy and the ability using incisional therapy to decrease the chance of incisional complications. So what you see here in their control, they had overall 30% incidents of surgical side complications. By using the Prevena or by using any type of incisional therapy in their case, again, it was use of the Prevena, not here to promote any type of specific tool, but they were able to significantly decrease the incidence of incisional problems and we’re able totally prevent sology three complications. So that has now become a standard for our distal bypasses. Then after we close the incisions, we put incisional therapy over those incisions and have been able to significantly decrease our incisional complication rate. Just an editorial comment, again, that there’s a very interesting poster that looks at incisional therapy with transmetatarsal amputations. We had know that in a dysvascular patient, when we do a transmetatarsal amputation, that there’s a significant incidence of incisional complications. And what the poster touch to, very similar to what we see or what vascular procedures they were able to decrease the incidence of incisional complications using the incisional therapy over their transmetatarsal amputation. Again, the incisional therapy is left in place for five days and then in general you have incisions with no incisional complications. The BASILs trial, a very important trial that looked, compared endovascular intervention with open bypass. Initially, the first reported results basically indicated that bypass versus angioplasty that the results were equivalent or were very similar. And this will add to, again, support for the endovascular first philosophy. However, when you looked at long term results and follow the patients out longer, number one significant number of these patients died, the association of coronary artery disease and peripheral artery disease, those patients that survive two years had better outcomes if they were treated with a bypass versus treated with endovascular therapy. So, this led to the support for those patients again that had perhaps significant claudication, early limb threatening ischemia, that you project those patients will live at least two years, that using bypass versus surgery was suggested as a result of this trial. And despite that, I can tell you that the majority of patients with peripheral arterial disease and limb threatening ischemia in this country are now treated with endovascular therapy. There’s been a threefold increase in the endovascular procedures even for claudication. When should we do it? I mentioned timing is critical. If you can get that patient before they have tissue breakdown it may simplify the operation that’s needed. So what happens after we do a bypass? Surveillance is very important. Dr. Joe Mills, other vascular surgeons have reported the results. Especially if you do a vein bypass and you do surveillance and you identify an area of stenosis and that vein bypass that if that secondarily treated, that the secondary assisted patency is equal to the primary potency whereas, if that bypass goes on to occlusion, trying to reopen a vein bypass usually is unsuccessful. So that surveillance picking up those areas of stenosis, that’s also important in patients that have had endovascular procedures. We’ll go back to the long covered stent, when those patients develop an area of stenosis it’s usually at either end of the covered stent, not within the covered stent.


    If that’s identified, then that can be treated with angioplasty, sometimes an additional stent versus waiting for that patient to go on and from those present in an acute ischemic state requiring lysis or re-operation, so surveillance of these patients, following the patients using the vascular lab becomes exceedingly important. So it’s critical either after a bypass or endovascular intervention using both ABIs but also with the vein bypass, it’s very important to use a duplex scan which can identify areas of stenosis where there may be little or no change in the ABI. When we’re working in a limb preservation environment, what I call the limb preservation huddle is exceedingly important. If you send a patient with diabetes that has a wound and you send that patient to the vascular surgeon and the vascular surgeon does a procedure and the patient is starting to heal but then plateaus that may well mean that that vascular procedure is now has developed an area of stenosis or has reoccluded. So, vascular assessment, the interaction between the podiatric surgeon and the vascular surgeon is not a one-time consult. It’s not a one time intervention. It’s a continuing dialogue. If that wound is not healing then does that patient need more vascular studies? Does that patient need more vascular intervention? So that continues interaction between the vascular surgeon and the podiatric surgeon, the wound care specialist becomes critical. I’m very fortunate to work in an environment where we have a team approach. Dr. Shade [phonetic] is in the audience. She’s our limb preservation podiatric surgeon. And again to have that dialogue, when things are going in the wrong direction, should we reevaluate, should we retreat the vascular surgeon? That’s a dialogue that is exceedingly important. So in summary, the interaction between the vascular interventionist and the podiatric surgeon and the wound care specialist is critical when we’re talking about limb preservation in a diabetic patient. No patient should have an amputation for critical limb ischemia without a vascular assessment. Now, on occasion and we’ve had some recent examples, patients come in with a significant infection, deep tissue infection that’s an emergency and certainly a debris month type of amputation is required and that’s done as an emergency and done before any vascular assessment with the exception that perhaps feeling pulses if we’re listening with a Doppler. But even at that point, then to back up and say is there adequate perfusion to reconstruct that patient at the lowest possible level and do we need to intervene that there is vascular disease to keep that final closure at the lowest level is very appropriate. So, key in preventing major amputations is a timely vascular assessment and appropriate vascular intervention. Again, I thank you all for getting up so early in the morning. We have time to go grab some breakfast then hear the good Dr. Freiburg. Thank you all very much.