Adili: Welcome to a new episode of “Focus on Vessels”, the podcast from the German Society for Vascular Surgery and Vascular Medicine. In this podcast, we aim to delve deeply into the topics that shape and advance our field. We’ll be discussing surgical endovascular and preventive vascular medicine, as well as science, teaching and clinical practice – in keeping with our motto: “We take vascular medicine further”.
Today, for the first time, we’re bringing you a double episode. The focus is on distal and ultradistal bypass surgery. Endovascular therapy has expanded enormously in recent years. Many procedures can now be performed using minimally invasive techniques, which are gentler on patients and often highly successful. At the same time, however, we also see a downside. The number of bypass operations is declining, and with it there is a risk of losing a skill that has, until now, been a true unique selling point of vascular surgery. This applies particularly to distal and ultradistal bypasses, which we used to perform much more frequently than we do today. These procedures are technically demanding, difficult to assist with, and even harder to truly teach and learn. It is not just excellent surgical technique that matters here, but the entire approach: the determination of indications, the selection of the right graft, perioperative management, and consistent follow-up care. All of these factors determine whether the bypass works at all, or whether it functions for 6 months, 6 years, or even longer. Today, I have invited as a guest on this podcast someone whom I have known personally for many years and hold in high regard, and whose bypasses have a particularly long lifespan. I am particularly looking forward to welcoming Dr Joachim Neufang, Head of the Vascular Surgery Department at Mainz University Medical Centre. It’s great to have you here, Achim.
Neufang: Yes, hello, Farzin. I’m delighted that you’ve brought this topic up with me. And I immediately said yes with enthusiasm, because I feel exactly the same as you do. It’s one of the central issues, and the fact is that these techniques are in some danger of being pushed into the background – completely unjustifiably, in my view. That’s why I’m also looking forward to the series of questions. And I think that both of us – you’re well versed in this too. It’s not as if I’m the only one here. I think that together we can tackle some key questions effectively. Over the next 30 to 40 minutes.
Adili: Yes, lovely, I’m looking forward to that too. And yes, let’s just get straight into it. A first question to warm up: what distinguishes a good distal bypass from a truly excellent one, in your view?
Neufang: Yes, that’s the question – it’s a difficult one, but a crucial one. If I were to describe a good bypass, I’d say it’s one that I can perform without complications. I manage to anastomose the target artery and restore blood flow. And the patient is then initially symptom-free. With an excellent bypass, I see the situation as one where you’ve already thought through from the outset what might endanger the entire system – which I’m now painstakingly constructing – in the future. Where might there be a problem in the future with inflow and outflow? With graft positioning, and I incorporate these steps, so to speak, into the planning structure of the bypass and operate – as I say in our day-to-day practice – I am, so to speak, operating on the future of this bypass in advance. And I try, as far as possible, to design it in such a way that not much can go wrong at critical points in the future. And that also applies to quite mundane things like potential local, post-operative complications. That you avoid wound problems or that you factor in the necessary wound management or minor amputation, things like that.
Adili: Yes, so anticipating future problems and doing practically everything possible to ensure these things don’t occur. What do you consider to be clear indications in the endovascular era for a distal or ultra-distal bypass – that is, a bypass connected distally or to the crural vessels? Or indeed to one of the pedal vessels or caudal vessels.
Neufang: Well, I’m not alone in this; we have our guidelines, and they are primarily based on morphology. And the first point is quite clearly an extensive arterial lesion spanning two segments, for example, long-distance occlusion of the entire femoropopliteal axis. From the femoral bifurcation beyond the popliteal trifurcation. Personally, I also see this as a good candidate for a sensible, long-term endovascular solution. For me, these are candidates for direct primary bypass planning, regardless of whether a suitable vein is available or not. However, I would also take the patient’s overall condition into account, namely a patient who, at the time of diagnosis, is still in relatively good general health, reasonable mobility, who understands their clinical picture and is likely to be compliant with regard to medication or attending follow-up appointments – I would also see such a patient, if they have a worn-out arterial pattern, as a clear candidate for primary bypass surgery. In that case, I wouldn’t go for endovascular treatment first. This applies all the more, of course, if I already know from the clinical examination that they also have an intact great saphenous vein on the affected side. So then that decision is very easy for me. The next point relates more to the very specific situation. I believe that the more diseased the foot – that is, the end organ – is, the more successful and intensive the revascularisation must be. You can, of course, see that at a glance. If a relatively large amount of tissue has already died and it is clear, for example, that following revascularisation I will not only have to perform wound treatment but a transmetatarsal forefoot amputation, then I should ensure that a strong pulsatile blood supply is established. So the patient will need a bypass for this to work out well. There are also relevant papers on this; it’s proven. The bypass procedure leads to better results in terms of healing and limb preservation in such patients. I met my American endocrinologist, who told me that for certain conditions, you need a strong, pulsatile blood flow in the foot. And then the fourth situation – this is something we’re probably confronted with on a daily basis; you’re in the same boat as me. What about the indication for a bypass in the case of a recurrence? And these are primarily patients who have already undergone several, primarily endovascular, treatments that have subsequently failed. Here too, I believe that if there is an extensive pattern, one should change the procedure, as in trauma surgery, and then switch to the surgical option.
Adili: Yes, we will explore some of these factors or criteria you’ve just mentioned in more depth – both in terms of patient-specific aspects and technical considerations, such as graft-related and target vessel-related factors. We’ll come back to that later. You’ve just summarised very well who, in your view, is actually the most suitable candidate for an ultradistal bypass. Are there also situations where you deliberately say, ‘This isn’t a good case for a bypass’?
Neufang: Do you mean endo, or are you referring to a bypass now?
Adili: No, I mean bypass.
Neufang: A patient who is in poor physical condition is not a good candidate for a bypass. Someone who, let’s say, also has very advanced destruction of the foot tissue. There are typical combinations such as extensive forefoot necrosis involving the proximal third, necrosis of the metatarsal outer edge of the foot, and then a large heel ulcer, possibly even with the heel bone already exposed. In this case, I would say that our entire revascularisation strategy is actually too late. I would not offer bypass surgery to this patient; instead, I would consider whether this patient would be better served by a targeted major amputation that preserves the knee joint as much as possible. I probably wouldn’t have done it that way 20 years ago. That’s the experience gained over many years, and I would then communicate that to my colleagues as well, because sometimes, when they’ve had several endovascular sessions under their belt, for example, they say, ‘it’s bound to work out somehow now’, but in doing so they’ve overlooked what the local condition is actually like; I think you have to convince the partners once again of the wisdom of the approach. Yes, so for me that’s more of a situation where I’d leave it at that. There is perhaps, as you mention, another borderline situation when considering an arterial bypass; I sometimes evaluate this with my partner, Christina Espinola-Klein. Patients who are in this ‘no-option’ situation. But that might be getting too deep; I no longer consider an arterial bypass – I used to do that sometimes in the past – where you have to consider major amputation or, in individual cases, think about arterialisation, but I don’t think we should talk any more about the subject today.
Adili: But it sounds as though, Achim, when you say the patient isn’t really suitable for a bypass, you’re implying they aren’t suitable for endovascular treatment either.
Neufang: Well, unfortunately that’s often the case. So, if I take the simple cases as a starting point, if I have a frail elderly person with serial stenoses in the femoral artery, there’s absolutely no question that today you’d perform angioplasty and, where appropriate, treat them selectively with stents. But if I have a case of this long-distance occlusion including trifocalisation, where, let’s say, a nice anterior occlusion starts in the distal third of the lower leg and extends down to the foot. But this patient has no mobility at all; he is unable to grasp what lies ahead for him, and it is difficult to communicate with him. In such a situation, I would not expect an interventionalist to go to the trouble of endovascular recanalisation, which is by no means a trivial procedure. Which I’m not, of course. I see it very much the same way. Yes, I think you should always use the endovascular approach very liberally where you have a simple, easily predictable pattern in front of you. That’s where the method is brilliant.
Adili: Imagine you have this patient you described, who may no longer be very mobile, but who has a well-connected anterior artery, let’s say a long one, but who is simply immobile. Where you’d say, ‘Goodness, performing a complex bypass on an immobile patient – the benefits and risks are hardly in proportion.’ Would that be a candidate where you’d say, ‘Before I amputate, let’s try endovascular treatment first’? Well, if it closes up, it closes up; perhaps you can open it up again, and if not, you still have the option of palliative or ablative treatment.
Neufang: Yes, I’ve got no objection to that at all, don’t get me wrong. You can give that a go. It’s just that personally, I believe that if I’re recanalising a segment from the femoral bifurcation down to the mid-lower leg, the prognosis is always questionable. I think in this situation – when you mention the case, because it is important – we should really look at the details again: how immobile is this person? Can they still stand on that leg, for example for their morning wash or similar? Of course, you could certainly say, ‘I’ll perform a bypass operation simply to maintain a bare minimum of mobility.’ Then that’s fine. But if they’re just lying in bed and already have a slightly contracted knee… I don’t know, I think that’s overkill.
Adili: Yes, yes, I see it similarly. Once you’ve made the decision to go for the distal bypass, the next step actually begins: the planning. Many of these operations aren’t just won or lost in the operating theatre, but already during the analysis of the imaging. Yes, that’s also the—that’s basically the decision: will this bypass ever work, can you even get it to work, or will it end in immediate occlusion, or will it be impossible to perform at all? And I think many people underestimate just how crucial this planning is. So, first of all, a series of small technical questions for you: when you look at the imaging. That’s usually a contrast-enhanced angiography, I assume, or would you say a CT angiography or an MRI angiography would be sufficient for you in the case of ultradistal target vessels?
Neufang: That’s a very difficult question; I’ve actually given it quite a bit of thought beforehand. There are various options. Let’s take the situation that we’re both probably familiar with: a patient undergoing standard angiological diagnostics. And then being evaluated with an angiography, with a potential angioplasty as part of that procedure. That is, of course, the ideal diagnostic approach; yes, because you can see the distribution of the contrast medium very clearly in sections. The first thing I look at, of course, is the condition of the periphery, where the best possible target vessel is, and how the contrast medium is distributed within that target vessel. I think that’s the most crucial step in terms of planning, because then I know what length I’ll probably need to bridge and what I can expect from that vessel.
Adili: So, if I may interject, the Angiosome concept isn’t really a major issue for you at this stage; you’re essentially matching the target vessel to the lesion location. Would you say you’re actually connecting the vessel that’s best suited?
Neufang: Absolutely. There’s plenty of good literature on that, too. When it comes to planning the bypass, the concept of the angiosome is actually completely secondary. Yes, that has also been sufficiently investigated. I can understand that; for endovascular procedures, it’s a different approach, but that plays absolutely no part in my thought process. There is perhaps a single exception, but those are again the patients where one has to be critical anyway. In the case of dialysis patients, it seems that if they have a larger defect, it is more advantageous, including from a surgical perspective, to ultimately address the diseased angiosome. But that is perhaps more of a marginal group. However, in my view, this plays no role in standard planning. You’ve raised something very important, though, namely what diagnostic tools are currently available to us. There’s the scheduled patient who is admitted via angiology and goes through a specific, structured algorithm. That’s quite straightforward for me; there’s a good angiogram. But then there’s also the patient who comes in via A&E in the evening with gangrene or something. And then this CT angiography is done, where you can see right from the start that there’s a long-distance occlusion extending right down to, I don’t know, the middle third of the lower leg. Do you then take the step of performing an additional angiography, or not? I think this is a dilemma you probably face yourself. The thing is, I believe you have to weigh it up, because CT angiography offers us a major advantage in that you can see the calcification clearly. I think it’s excellent for assessing the inflow; you can also see the condition of the femoral bifurcation and prepare quite well for it. It’s a bit tricky, though, when I’m looking at the lower leg arteries in diabetic patients – the calcification gets in the way. If I can then see the vessels near the ankle clearly and know where I can go, and if I create a 3D reconstruction of it and rotate and manipulate the whole thing for a while, then I no longer necessarily need an additional angiography. If I have any doubts, I ask my colleague to perform an angiography with imaging of the lower leg and, above all, the ankle region in two planes. You mentioned a third thing, which is MR angiography. I believe that’s often initiated by third parties. In private practice, they’ll have an MR angiography done and never actually see the images themselves. Yes, and I think that’s the most difficult type of imaging, because you can’t see anything there—the calcification—it’s simply not possible due to the method, and in the periphery you either have overlaps that make interpretation difficult, or, again due to the method, sometimes the foot simply isn’t visualised properly. So we are reluctant to use MR angiography as a primary method. But there is a specific advantage that this method can offer. Namely, I don’t know if you’re familiar with the work of Karl Kreidner. He is one of the radiologists from Mainz who has worked very intensively on MR technology, and about 30 years ago he developed a technique where he used a joint coil and inserted only the foot – the affected foot – thereby achieving a selective MRangiographic imaging of the pedal arteries and the lower leg region. And I am absolutely amazed at what this method can sometimes achieve. It’s just not available to us again. We have it; we use it selectively. So if you can’t really see it clearly in standard angiography, it’s astonishing what this MR angiography can sometimes reveal. And I try to combine these three things, and then you can actually manage quite well in the planning stage.
Adili: Well, sometimes things do fail down to the trivialities of everyday life. I mean, when we’re talking about ET-MR, but also sometimes about catheter angiography, we don’t always get the quality we need. The contrast agent isn’t where we need it to be when the image is taken, so I have to be honest: when I’m considering performing a bypass, catheter angiography is actually the gold standard for me. In my opinion, it really does provide the best spatial resolution, and you also get a feel for the downstream dynamics of the contrast agent. Do you see what takes up more? Yes, perhaps not the vessel that necessarily appears thicker in the image. But that it has better or more collaterals – yes, that’s also the reason why the fibular artery often works very, very well. Yes, even though it doesn’t cross the ankle joint and is still successful because there’s simply flow there, and that combination of flow, image and resolution – I still find that simply unbeatable with catheter angiography. So, if in doubt, that would be the best approach for me, and anything else is a compromise one then has to accept.
Neufang: Exactly. Well, I do it that way too – or we as a team – so that when Ms Espinola-Klein is performing an angiogram on a specific patient, she always gives a quick call before it’s time, and someone joins in and we then take a look on the spot. Yes, well, I have to agree with you wholeheartedly there, but it’s just not always possible to do that, is it. And then you just have to see how to deal with it. You also have, I think – I don’t know if you’ve already mentioned it – duplex sonography
Adili: No, not yet, but that would be interesting. What do you think of duplex sonography?
Neufang: It’s, let’s say, very helpful when I have a patient with advanced renal failure, where you have to be very careful with contrast agents. You can combine CO₂ with a bit of contrast agent, but I wouldn’t tend to do a CT scan on these patients; instead, I’d try the CO₂ or contrast agent – or I have a very good sonographer, as I’m not one myself. It’s brilliant, to be honest. And he shows me very clearly where a vessel is clearly visible on the ultrasound. And he can basically, or that person can often visualise the run-off as well, and in the past I’ve also operated on many patients, particularly in this intermediate stage of renal insufficiency, without contrast-enhanced diagnostics, but solely based on the ultrasound. That works quite well.
Adili: Let’s move on to another key point: the ideal or best conduit. So, we’re both in agreement. I think it’s worth discussing which is the best material for creating such a bypass; that’s undoubtedly the great saphenous vein, and if it’s available ipsilaterally, then all the more so. If you don’t have that – and that’s actually not that uncommon – I mean, it’s already been used, it’s been stripped, it’s sclerotic, ipsilateral, and what’s your next step in the algorithm? What do you look for first? How would you practically draw up a shortlist of the bypasses or conduits you would create to get a distal or ultradistal bypass working?
Neufang: That is, of course, the crux of the whole matter, because the ideal scenario is just that – ideal – but you don’t encounter it every day, do you? The very first thing I clarify is: what is the route from A to B? What length will I need? Are there any modifications that might reduce the length, allowing me to make do with a single, albeit limited, but continuous piece of vein? Let’s run through this mentally: the contralateral great saphenous vein usually offers reliable quality if the vein is there and intact, but is the contralateral limb healthy or not? It often isn’t, and perhaps, on closer inspection, it already has some issues in the foot. A black spot somewhere, and it’s out of the running straight away; you can forget about it. I’ve become a very, very, very big fan of the arm vein, I have. I always like to say that too. I used an arm vein for the first time in 1995, because I’d read in the literature that it could be done, and because Herbert Dardik – he was one of the American surgeons who influenced me – had once pointed it out to me. I had no idea that was possible. And as I said, we started using the arm vein regularly in Mainz 30 years ago, and it’s something that’s completely underestimated. It works beautifully for performing bypass surgery using the arm vein. You just have to assess it beforehand. In the simplest cases, a clinical examination of the patient alone is sufficient. You look at their arms; if they’re men, you can use a tourniquet, apply it to the upper arm, and they clench their fist as if for a blood test, and then you can already see the course of the veins. That’s the simplest case. The complicated one is a strong, fleshy upper arm. Then you need an ultrasound, but that works brilliantly. So, I’ve certainly performed over 800 arm vein bypasses since I left Mainz in 2010, and when I was in Wiesbaden, it was about 450. That’s a lot, and it’s underestimated – something I really want to highlight. Next is the saphenous vein.
Adili: May I just interject briefly with a small caveat – the patients are, as we all know, elderly; they’ve often been in hospital before, and their cephalic vein in particular has frequently been punctured by indwelling venous catheters. Blood sampling in the antecubital fossa often causes such webs in the veins; so the forearm vein—I’d make a qualitative distinction there compared to the upper arm vein. So, in my experience, a section of the upper arm vein is usually of higher quality than the forearm vein, which is often quite battered. And I think you have to be careful there, even if the vein dilates well after compression.
Neufang: Yes, you’re right. It’s only a guide; with the arm vein, the true assessment comes after the draw. And you also have to be prepared to make long incisions and put a lot of effort into it, and then assess that very critically. You wouldn’t believe how often the piece flies out at the elbow with me. Because it’s exactly as you described.
Adili: What about the parva?
Neufang: The parva is somewhere in between; it’s relatively superficial too. But it doesn’t always have the necessary calibre. It’s sometimes small, and I find it’s often sclerotic or indurated.
Adili: Yes, or shimmery, as we like to say here. It’s got this odd thin wall, fragile, lots of branches – so you don’t always get that happy with it either.
Neufang: Absolutely. And that’s why, for me, it’s in the third tier, so to speak. There are also situations where you have a great Pava that sometimes runs all the way down the Giacomini vein to the thigh. Those exist too. You can do a Fempop with that. But that’s a rarity.
Adili: Yes, Achim. And this is exactly where it gets particularly interesting. We’ve seen that the patient’s own vein remains the primary graft material, but in reality it isn’t always available in the ideal length and quality. And that brings us right to the threshold of procedures where experience, planning and surgical precision play a completely different role. Dear listeners, we’re deliberately cutting here. That was Part 1 of our discussion on distal and ultradistal bypass surgery with Dr Achim Neufang from Mainz University Medical Centre. In the second part, we’ll discuss the significance of composite procedures today. How to carry out tunnelling, anastomosis planning and intraoperative monitoring properly, and why this often determines whether a bypass functions only briefly or remains open for years. Joachim, thank you very much so far for the clear explanation and the many practical tips. And to you, dear listeners, thank you very much for listening. Please do subscribe to our podcast so you don’t miss the second part. We’ll pick up again at exactly this exciting point.
Until next time!
