Rantner: Welcome to a new episode of “Focus on Vessels”!
My name is Barbara Rantner; I am a vascular surgeon and senior consultant, now at TUM Hospital on the Right Bank of the Isar, but still based in Munich. This podcast is designed to offer you, our listeners, a platform to delve deeply into the topics that shape and advance our field. Together with our guests, we’ll explore the latest developments in surgical, endovascular and preventive vascular medicine and discuss current topics from science, teaching, clinical practice and the real world. True to our motto: we take vascular medicine further. Today’s episode is a very special one, not only because we are addressing the vital topic of diabetic foot syndrome, but also because I am delighted to welcome you fresh from our annual conference in Lucerne. As you are no doubt aware, a tri-national conference of the German-speaking societies for vascular surgery takes place every three years, and so we were able to spend some fantastic days in wonderful Lucerne, filled with science, interaction, inspiration and friendship. And against this backdrop, I am particularly delighted to finally have two guests by my side again today. As you know, this was the case in the first episode, but not since then.
Today I am delighted to welcome Hartmut Görtz and Christian Alexander Behrendt. As a consultant in Lingen for over 20 years, Hartmut Görtz has worked extensively in the field of vascular medicine, devoting particular attention to diabetic foot syndrome. Christian Behrendt runs a clinic in Hamburg and is head of the DIGG, the German Institute for Vascular Medicine and Health Research. And both work side by side on the DGG’s PAVK Commission, which also deals with diabetic foot.
So, as you can see, I couldn’t have found better guests for this podcast, and I’d like to thank them both in advance for their time and for joining me in this conversation.
Behrendt: Thank you very much, dear Barbara, for having me, and I’m looking forward to today’s conversation.
Görtz: Me too. Thank you very much, Barbara.
Rantner: Well, diabetic foot syndrome is a very complex clinical condition that combines various pathophysiological aspects and consequently requires a wide range of disciplines in its management. We, as vascular specialists, are heavily involved, as over time – depending on how the condition develops – vascular findings often need to be assessed and treated alongside the metabolic aspects. Christian, I’ve already mentioned that you’re very deeply involved in healthcare research through the DIGG. Could you give us an insight into how frequently we diagnose diabetic foot syndrome in Germany and how often we identify it specifically in connection with PAD?
Behrendt: Yes, healthcare research always comes first. That’s usually the introduction to epidemiology in the guidelines as well. In fact, it’s not at all trivial. There are a few figures that are repeated time and again. It is said that around 8 to 10 million people are affected in Germany. But if you approach the whole thing, shall we say, a bit more systematically, you can assume a total prevalence in the population of, say, 10 to 12 per cent, based on international data from epidemiological studies as well as healthcare data. Among those over 65, the figure is around 20 to 25 per cent. But these are only diabetics. That does not necessarily mean they have critical circulatory disorders. Of these diabetics, about a third develop an ulcer. These are the people covered by the current guidelines of the International Working Group on the Diabetic Foot – that is, people with diabetes and an ulcer.
And of these, depending on how you look at it, up to 50 per cent also have severe AVI, i.e. a severe circulatory disorder. These are the cases we typically see in vascular surgery as circulation-related wounds in diabetics. If we look at the proportion of care provided – that is, what does this amount to, how many are there – according to my current estimate, we have around 500 hospitals in Germany that are actively involved in this. It may be slightly fewer. And one can bear in mind that just under 30,000 bypasses below the knee, i.e. infra-angular and below-knee bypasses, are billed each year. 15,000 major amputations and around 50,000 toe or minor amputations. And from that, you can roughly gauge the workload associated with diabetic foot syndrome and circulatory disorders. But these are all just estimates. I’m not aware of any really good prospective epidemiological cohort studies or the like that would observe or screen for diabetic foot syndrome and provide current data. These are mostly just inferences based on prevalence figures, if you like.
Rantner: Yes, wow, those are really very impressive figures. Christian, perhaps we could briefly discuss the age distribution among those affected? The classic PAD patient is usually over 70. As we know, diabetics are often affected at a younger age. Do you have any figures on this that you could summarise for us?
Behrendt: That’s actually quite significant. What we can say is that, generally speaking, the older people—or those affected—get, the lower the prevalence of diabetes. We once looked at a clinical cohort of people in hospitals who were actually over 90 years old, and there was an extremely low prevalence of diabetes, which supports your theory – or, to be honest, this is actually common knowledge – but the fact is that it occurs earlier in life, so to speak, or in the course of the disease, and these patients have other problems besides just foot ulcers; they also suffer from heart attacks, strokes, etc. That is why we see excess mortality. That’s why I wouldn’t dare to make such a crystal-clear, shall we say, distribution of prevalence across age groups. Of course, it becomes more common with age, but then at some point there’s a turning point, a peak, where it becomes less common again, because the peak, so to speak, has been passed. However, I would also say that people with severe diabetes, with vascular complications or something like an angioneuropathic diabetic foot syndrome, probably reach their peak incidence somewhere between 65 and 70, and what I’d call smoking-related AVK, to put it quite bluntly, would in my view be more like 70–73 or 69–73. But to be honest, these are all just clinical data.
Rantner: Yes, well, as I’ve already said, that really does underline the importance of the topic for vascular specialists, but also for many other disciplines. Now, as vascular specialists, we’re used to working in an interdisciplinary way, and yet, in my view, patients with diabetic foot syndrome still present a particular challenge. Diagnosis is often difficult, and treatment also requires an incredible number of disciplines that have to mesh together like cogs in a wheel to enable the best possible outcome for a patient. Hartmut, in your opinion, what should comprehensive treatment for these patients look like, and which disciplines do you believe should be centrally integrated into the care of patients with diabetic foot syndrome?
Görtz: Well, we are, of course, already extremely stretched in terms of interdisciplinary collaboration when it comes to diabetes mellitus or diabetes-related conditions. This is, of course, primarily linked to diabetes mellitus itself. It is a metabolic disorder, and treating it is not primarily our core business as vascular specialists; rather, we need the expertise of diabetologists, and there are now new developments in this area with new medications. I am thinking of GLP-1 analogues or SGLT2 inhibitors, which appear to play a very positive role, particularly in vascular diseases. However, when these patients come to us – and these cases usually involve ulcers, wounds or perhaps infections – the first question we really ought to ask ourselves is: why has this wound actually developed? Of course, the question always arises as to whether it is primarily angiopathy, i.e. the vascular disease, that is the main issue, or what about polyneuropathy? With angiopathy, it is indeed relatively difficult to diagnose. We know that many of our usual methods, such as measuring the ABI, are unreliable due to Mönckeberg’s medial sclerosis.
We measure falsely high pressures. The ABI is therefore too high. The tobrachial index seems to be somewhat better, because the peripheral vessels of the little toes are not so badly affected. However, this is not always easy to determine technically either. In this context, it is also recommended to assess the waves in continuous wave Doppler to determine, for example, whether we have monophasic or biphasic signals. However, none of the three parameters on its own is actually suitable for making a valid statement on this, so the recommendations are to assess these parameters collectively, to evaluate them as a whole. So, for example, if someone has an ABI of less than 0.9 or greater than 1.3, if the Tobrachial Index is less than 0.7 and monophasic signals are present, then they will certainly also have PAD. Furthermore, in my opinion, electron oscillography has still proven its worth in practice; it is slightly more sensitive in cases of diabetes mellitus or Mönckeberg’s medial sclerosis. A method which, I believe, not many colleagues perform anymore. And ultimately, the clinical examination as well. For example, the recapillarisation time to determine whether ischaemia is present, or performing a positional test according to Ratio, would be another way to assess how significant the ischaemia actually is, or how significant the reduction in arterial perfusion actually is.
Rantner: Might I perhaps interject with a slightly critical question here, Hartmut? You’re saying that these are all very detailed vascular examinations. To put it somewhat bluntly, how relevant is all this to clinical practice? If I were to see a patient with diabetic foot syndrome, one would actually always carry out a vascular assessment, and in cases of doubt even perform an angiogram, in order to assess the lower leg perfusion situation in detail. And then, if there’s something to revascularise – and I don’t want to overuse the ‘Angiosome’ concept here – but then you’d probably go ahead and do that as well. Or what’s your take on this? I mean, I do understand that it’s relevant for documentation purposes, but if listeners are now thinking, ‘Oh dear, that means I’ll need a whole lot of additional diagnostic tests,’ then they might not want to delve into the subject too deeply. Please could you say a few words about that again?
Görtz: Well, I do think it’s important to give this some thought, because we basically have to assess to what extent the angiopathy is responsible for the foot ulcer. In non-diabetics, this is relatively straightforward. We have reduced arterial perfusion, we have an ulceration, and we attribute this to the reduced perfusion. In diabetics, a second factor always comes into play: polyneuropathy. And this is something which, in my experience, has often been neglected by us as vascular specialists in the past. It’s an area where we definitely still need to acquire a fair bit more knowledge. In this respect, diabetologists or foot surgeons experienced in diabetic foot syndrome are, in some cases, considerably ahead of us. In that respect, it is certainly important to consider whether I should focus primarily on the polyneuropathy and treat that first, or whether I must definitely perform vascular reconstruction whilst treating the polyneuropathy at the same time. In my view, it is certainly worth questioning whether it makes sense to perform reconstruction on the foot in cases of severe polyneuropathy with typical ulceration on the bony prominence, simply because there are currently two stenoses in the lower leg vessels. This is certainly done, but it does not seem to be effective.
Rantner: Would you like to say something about that, Christian?
Behrendt: I wouldn’t want to sell us short as complementary vascular specialists, which is what we are, and many of us are now equally active in both endovascular and surgical fields. Of course, I recognise that not everyone approaches diabetic foot syndrome with the same attention to detail as you, Hartmut, or myself, or Barbara and others. But I believe that, generally speaking, it’s important above all that we approach the whole issue as vascular surgeons. And I think you’re absolutely right that purely neuropathic ulcers and pressure relief through orthotics and bandage shoes and so on – that’s perhaps also a bit of a compliance issue, and it’s often simply a care issue outside of inpatient treatment. That’s certainly how I see it in our practice. But for me, in every case of diabetic foot syndrome, it’s essential to, shall we say, rule out relevant ischaemia. And if we have indications – and yes, I see it exactly as you do – there isn’t really any high-quality evidence that would highlight a specific diagnostic criterion. That’s why, in the current guidelines, it’s all formulated merely as a ‘best medical’ or ‘good practice’ statement. But if we see two relevant stenoses there, I don’t consider a, shall we say, dogmatic avoidance of revascularisation to be necessarily better, because I, too, have seen thigh lesions that lead to a small ulcer, and once those are gone, the ulcer suddenly heals. And I, too, have seen an infected or severely infected ulcer which, although it primarily arose due to polyneuropathy, nevertheless saw an improvement in blood flow leading to wound healing. So I believe it’s all highly individual. But what’s important to me is that we don’t just leave it at that – that we, as vascular surgeons, aren’t simply unable to treat this without other expertise. I think it’s important that we take this on as our core focus.
Rantner: Perhaps I can pick up on that again to elaborate on the question of who should be involved in the treatment and care of these patients. Hartmut, that’s where we started. So if you were to imagine this wonderful foot centre, so to speak, where everyone who is best qualified treats the patient, who would you see there in that context for a patient with diabetic foot syndrome?
Görtz: Well, the vascular specialist is, of course, essential; there’s no question about that. I don’t think I’ve commented on who should carry out these examinations afterwards or the foot therapy either. It’s not as though we, as vascular specialists and surgeons, aren’t capable of learning and doing that. But we have to do it. Otherwise, of course, the diabetologist is our key partner in this field, in my view. And we also absolutely need someone with the relevant expertise in the field of foot surgery. We can, of course, develop and acquire this expertise ourselves. Because we have a huge problem when it comes to foot surgery. There are around 10,000 orthopaedic surgeons and trauma surgeons in Germany. 10% of them are foot surgeons, so 1,000. And of those, only 10% deal with the diabetic foot, so 100. That is not a large number for such a big country and for so many people. We have a major care provision problem here. And I know a number of vascular surgeons who are grappling intensively with this problem. This is certainly an opportunity to develop solutions and then provide our patients with good care. So, from our specialist field’s perspective, we certainly have the opportunity to take action here.
Rantner: We’ve actually recently discussed this topic on the board in Lucerne as well, and it was suggested that it might make sense to to establish a certificate for diabetic foot syndrome and its management, in order to clearly define the requirements for surgery, to map out facilities, surgical equipment and expertise, so to speak, and then to open this up to different disciplines so that, as you say, the shortage of available foot surgeons can be addressed by other disciplines. Is this already a concrete plan, or is it something that’s still in the planning stages?
Görtz: Well, for now, that’s what’s in the planning stage. But the planning is already well advanced and we’ve cleared the first major hurdles. Basically, it’s not just us as vascular surgeons who’ve realised that we sometimes lack the necessary contacts in the form of foot surgeons. Diabetologists have also realised this, as they too lack these contacts when, for example, they primarily keep these patients in their own practices or treat them in their clinics. This varies from place to place. The orthopaedic surgeons themselves, the foot surgeons themselves, have realised that there is a shortfall here. And on top of that, many of the highly experienced foot surgeons who deal with diabetic foot syndrome have now reached an age where they will be retiring soon. And there is certainly a risk – or so it is seen – that this knowledge will be lost. And the idea is simply that we try to pass this knowledge on to those who are interested.
Rantner: You both know this, of course, and so do our loyal listeners. In the last episode, I had the opportunity to speak with Uli Rother about the PHVK guidelines. Christian, as we’ve already noted, this mammoth work now includes a great many updates and new recommendations regarding patients with peripheral arterial disease. So what is the current situation for diabetes patients? It isn’t explicitly covered in a separate chapter, so to speak. But are there also new recommendations for the patient group with diabetic foot syndrome?
Behrendt: Yes, that’s actually a fascinating question, because there are so many overlaps. And we’ve just heard about it from Hartmut. One can focus more on metabolic control. One can give more thought to the topic of vascular reconstruction and revascularisation. And depending on the situation, it naturally makes sense to simply include the topic of diabetic foot syndrome within a guideline or to create a separate guideline. There is, in fact, an international guideline on diabetic foot syndrome. That is just one part of a major body of work by the International Working Group on the Diabetic Foot. And, to be honest, we published a new edition of that less than three years ago, which is currently being revised again. So the revision process is just getting underway. That’s why there’s already an English-language set of guidelines that has been published quite widely in various journals, where recommendations can be found – or would be found – that are somewhat more specific. If we’re really talking about substantive recommendations, to be honest, when you look at them, there are a great many best-practice statements and a low quality of evidence. So these are mostly observational studies or subgroups from randomised controlled trials. I think it’s a no-brainer that, of course, you should take a medical history in all diabetic patients with an ulcer. You should somehow screen for or rule out peripheral arterial disease. None of this is really new; yes, we should all actually know this. What’s also in there is that vascular specialists from all disciplines should be consulted first to assess whether revascularisation is required or not. And I think it’s clear to everyone that we need risk stratification. So for me, people with diabetic foot syndrome are always a bit of a minefield anyway. A lot can go wrong, and that’s why I would invest much more time in risk stratification. What we already have in these guidelines is, in fact, such a weighing-up based on BASIL2 and BestCLI. And if we’re honest, around 60 to 70 per cent of the patients included in these cohorts were diabetics. That doesn’t mean that every single case was, per se or by definition, diabetic foot syndrome. But it is, of course, an obvious association, and that is why the studies are suitable for drawing some conclusions from them. That is why, for example, there is the recommendation that, in the case of a good single-segment vein, one should primarily consider surgical intervention rather than endovascular treatment, and such matters, which we now all simply have to re-evaluate in the new edition with the new data and perhaps discuss a little more critically. There, too, as in the German S3 guideline, there is a greater focus on a patient-specific approach, where inflow into at least one of the lower leg or foot vessels is favoured. So that’s all very operator-dependent, individual, let’s say, in terms of how it’s done. What we’re also currently working on, which will hopefully be included to some extent in this update, is the prospective German VASC cohort study, which included around 30 to 40 per cent of patients with diabetes. That brings the total to, I’d estimate, around 1,500 patients, roughly 1,600. And then we need to identify those with critical ischaemia, for whom we also intend to provide some subgroup analyses. And all of that is intended to be included to some extent in this update. To be honest, there isn’t much more to say on the matter, that’s true. But in addition to the points Hartmut has already mentioned, we need to make a greater effort regarding SGLT2 inhibitors or GLP-1 receptor agonists, so that they might at least be included in the report. I don’t know how it is for you, but we are often asked about the cardiological indication. So they want us to provide an echocardiogram report so that at least moderate heart failure is somehow included in the findings. Because everyone is afraid that this might lead to major recourse claims. But honestly, these are things that need to be included in such guidelines, even if they are surgical guidelines. But I really can’t say much more than that. To date, we don’t really have any great studies that we can incorporate into these guidelines regarding invasive revascularisation.
Rantner: Just a quick side question. Is the Angiosom out or in? Are we sticking with it for diabetics?
Behrendt: Well, we’re talking a lot about the Wundosom at the moment. There are various approaches one can apply. And what I perceive as the most controversial point of discussion right now, Hartmut – I don’t know how you see it – is simply that one should incorporate the management of the wound region, the three-dimensional management of the wound region, a bit more on an individual basis. And for that, you simply need a good, at least two-level approach: angiography and so on. But that’s very much about endovascular foot reconstruction. That’s probably not always entirely relevant for surgical revascularisation. We also heard recently in the DGG’s bypass survey just how differently everyone approaches this. I’m unsure how this will catch on, because ultimately it’s still just a concept at the moment, without a study to validate it. I don’t know, Hartmut, do you perhaps see it differently?
Görtz: Well, I believe that with diabetic foot syndrome, it is essential to ask why the wound is forming in that particular spot. And in most cases, there are certain structures in the foot that play a role there. For example, changes in the claw toe and so on. Or exostoses that play a role. And I think it’s just important to bear precisely this in mind. And then it might also make more sense to treat or remove the exostosis first, or reduce the pressure, before addressing these questions. I believe reconstruction is crucial to ensure sufficient blood flow into the foot in the first place. As for the Angiosome concept, we actually know that it obviously plays a role in endovascular reconstruction. With open procedures, this does not seem to be the case to the same extent. As I said, my appeal here is to remember that neuropathy is also present and that one must keep the foot’s physiology and pathophysiology in mind.
Rantner: Well, I think we’ve already managed to convey to our listeners the complex demands that patients with diabetic foot syndrome place on all the disciplines involved in their care. Hartmut, just to round things off, one final question: will we even be able to manage this in the future? I suppose I’m in a university centre. I don’t need to worry too much about foot surgeons. And the diabetes department is well integrated. But in this age of resource optimisation and cost-cutting, I believe it could well be the case that these patients end up being somewhat neglected when it comes to the complexity of their care. What’s your view on that?
Görtz: Well, under current conditions – and indeed future ones – this certainly presents a very special challenge for everyone involved. All the more reason to create effective networks here that will then make the treatment of these patients more successful. However, this in turn must also lead to a reduction in the number of amputations, in line with the San Vincente Declaration. If we succeed in that, then it should actually be possible to achieve both: In other words, to prevent the costs per case and the follow-up costs from rising further. And to improve the quality of treatment. However, and this is somewhat of a counter-argument, if everyone works in their own bubble – which is the case for many vascular surgeons, for example – thinking, as I said, only of stage 4 PAD in diabetics without taking polyneuropathy into account. If the wound specialist only thinks about which dressing to apply to the foot without thinking further, and the diabetologist only thinks about the metabolic situation, then we will certainly not be successful, and costs will also rise enormously due to the huge number of amputations that will follow. So, in my view, networking is also indispensable for the future from an economic perspective. The fact that we, as vascular surgeons, should play an important, perhaps even a very important role in this is absolutely crucial to me, and it essentially depends on us whether we do so or not.
Rantner: Christian, what else do we need to be mindful of? Where do we still need to raise awareness? Looking at the current healthcare landscape, where do you think the most educational work is still needed?
Behrendt: I think I would say that diabetic foot syndrome is a prime example of integrated care. I believe we need what Hartmut referred to as a network; we need cross-sector, well-functioning care, because patients tend to move back and forth between a good diabetes clinic – which deals precisely with these metabolic adjustments and minor wound treatment – and then, when revascularisation or a major amputation is required, they switch to hospitals, and so it goes back and forth a bit. I get the feeling, sometimes in conversations, that this works better or quite well in long-established centres, but across the board, the patients affected perhaps disappear from view a little bit because, after inpatient treatment, they simply cannot access a good diabetes clinic. And let’s all be honest, I mean, they usually come to us in a different situation, and often the infection is already very advanced, so it’s simply important that we exchange information somehow. I believe that awareness of the topic itself, and above all of the benefits of this surgery – and also what Hartmut and you have just illustrated with the DGG certificate – is something that is and will remain our bread and butter in the future, if we bear in mind the figures from the start. And that is why this is something where we also need to raise or increase awareness within our field and amongst our colleagues who are part of the DGG network, because it’s not just all about aortic arch interventions or, shall we say, rare compression syndromes that occur in fewer than one in a million cases, but rather about things with which we can really help people. And that’s why I think it’s great that the DGG offers such certificates, just like the prevention assistant programme, which is currently being established and offered in parallel by the DGG’s private academy. Because that too – precisely these metabolic adjustments, and not smoking – is just as important for diabetics, or perhaps even more so.
Rantner: Yes, I can’t really add much more to that. A wonderful topic that we were fortunate enough to discuss as a trio. I’ve really enjoyed it with you both. I’d like to thank you once again for taking the time for this discussion. And of course I’d also like to thank you, dear listeners, for dedicating your time to us once again. We’d love to hear your questions or feedback. You know that already. Please feel free to write to us at podcasts(at)medizinkommunikation.org. If you’re listening to us on Spotify, you can also leave us a rating. The better, the better, of course. And I’m already looking forward to one of the next episodes. Please do tune in again. Until then, I wish you all the best. Stay curious and stay healthy.
