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Podcast Transcript: Challenging Stroke Thrombectomies with Tough Clot

with Dr. Matt Gounis and Dr. Hannes Nordmeyer

Interventional Neuroradiologist Dr. Hannes Nordmeyer and Biomedical Engineer Dr. Matt Gounis discuss compositions of tough clots, approaches to stroke thrombectomy, and bailout stenting. You can read the full transcript below and listen to this episode here on BackTable.com.

(1) Optimal Thrombectomy Technique and Equipment

(2) Future Thrombectomy Technologies and Factors for Success

(3) Stent Retrievers vs Aspiration Catheters

(4) Nimbus Device vs Standard Stent Retriever

(5) Intravascular Imaging: Optical CT and IVUS

(6) Angioplasty and Antiaggregation Regimen

(7) P2Y12 Inhibitors and Incidence of Intracranial Bleeds

(8) When to Stop Making Passes

(9) Post-procedural Management and Thrombectomy Safety

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Ep 178 Challenging Stroke Thrombectomies with Tough Clot with Dr. Matt Gounis and Dr. Hannes Nordmeyer

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[Dr. Michael Barraza]:
Today we’re back to talking about stroke interventions. We previously reviewed IR and stroke interventions at episode 74 and 75, and then in episodes 98 and 132, we talked about artificial intelligence and stroke management. Then more recently in episode 144, we debated direct aspiration versus co aspiration technique for thrombectomy. In today's episode, we're going to talk about challenging stroke thrombectomies and dealing with tough clot. It's an honor to welcome our guests: Dr. Hannes Nordmeyer, Chair of the Department of Interventional Neuroradiology in Solingen, Germany at radprax, and Dr. Matthew Gounis, biomedical engineer, professor of IR and neuro IR, Science Director of Advanced MRI, and Vice Chair for research in the Department of Radiology at the University of Massachusetts and at least a dozen other titles and accolades that I don't have time to go through. Gentlemen, welcome and thank you for sharing your time with us today.

[Dr. Matthew Gounis]:
Thank you. It's a pleasure to be with you.

[Dr. Michael Barraza]:
So both of you have been and remain major contributors to the understanding and advancement of stroke care, and before we dive into our topics, I want to give our guests the opportunity to get to know who you are and what you do. Starting with you, Dr. Nordmeyer, could you tell us a little bit about your practice and the role you play in stroke interventions at radprax?

[Dr. Hannes Nordmeyer]:
Yeah, sure. I learned with René Chapot in Alfried Krupp Krankenhaus (Essen) for more than a decade and since three and a half years, I'm running the Neurointerventional Department at the St. Lukas Hospital in Solingen with radprax. We build up a completely new department with a completely new team, and from the beginning on, we started with a 24/7 service, and we're doing stroke interventions as well as hemorrhage cases, so the whole spectrum of neuro interventions.

[Dr. Michael Barraza]:
What kind of volume of stroke do you guys see in a given year or month?

[Dr. Hannes Nordmeyer]:
We're doing 180 strokes this year. Probably last year we did 150. So we're all rising numbers from year to year and serving a wide area around the city of Solingen.

[Dr. Michael Barraza]:
Who all does these stroke thrombectomies at your institution? Is it just your department or are neurosurgeons or other practitioners involved?

[Dr. Hannes Nordmeyer]:
So there are just a neuroradiologist doing endovascular stroke treatment, and that's a team of three: Timo Huan Phung, Stephanie Neuhaus, and me, and we are running the 24/7 service, the three of us. We are collaborating with a neurology department and neurosurgery, of course, and vascular surgery.

[Dr. Michael Barraza]:
Sure. It sounds like you guys have a full stroke team that gets involved in these cases.

[Dr. Hannes Nordmeyer]:
Yes, it's a big stroke unit that is serving over the borders of the city, over regional stroke unit, as we call it in Germany.

[Dr. Michael Barraza]:
Dr. Nordmeyer, you’re also, of course, heavily involved with research and furthering what we know about treating stroke and other neuro procedures, such as aneurysm and embolization. How did you get involved with some of the more recent trials you're doing, like the ARISE II study?

[Dr. Hannes Nordmeyer]:
Yes, we were involved with the ARISE II study with the neurovascular department in Essen a couple of years ago. And, I think we contributed quite a lot of cases to this trial. And, now we're involved in other stroke trials for thrombectomy and treatment of intracranial stenosis in acute and elective cases. So that's our main topic where we’re involved in multicenter trials.

[Dr. Michael Barraza]:
Good, I look forward to seeing the results of those. All right, Dr. Gounis, it’s your turn. I got to tell you, looking through some of your more recent publications, I was really struck by the depth and diversity of what you're investigating, not just equipment, but we're also talking about the biomechanics, hemodynamics, clot composition, vessel wall effects, intravascular imaging, microvascular effects after stroke, and even talking about like radial access and animal models. So I was going to ask you, how did your career take you? I mean, from a biomedical engineer and a philosophy PhD to becoming an international expert on neurovascular disease and intervention and on the editorial boards of really most of the relevant journals in this field.

[Dr. Matthew Gounis]:
I was just really fortunate. When I was an undergraduate student at the university of Buffalo, I got an opportunity to get this scholarship and basically was handed a book. And so, when I was at university, I was studying to be an aeronautical engineer, so I was going to go build airplanes. And I got this book of research projects, and it was a program investigating flow diverters. And this is in the early nineties, and that was with Ajay Wakhloo and Barry Leber. And, so as an undergraduate student, I got involved in neurointervention and just became really passionate about the space. I'm just really fortunate. I'm still young person, but that my career started, from the beginning, just solely looking at neurointervention. I was just also really fortunate. Nick Hopkins had created a world renown center, investigating neurointervention. And, that was called the Toshiba Stroke Research Center at the time, and it subsequently is now the Jacobs Institute. But, anyways, just a really amazing opportunity to get in at a time where the coil was just being approved by the FDA. So really the beginning of modern neurointervention. It's just really good fortune.

[Dr. Michael Barraza]:
You're also director and co-founder of the New England Stroke Center. Can you tell us how and why you established that and really what you plan to do with that?

[Dr. Matthew Gounis]:
Yes, so that was back in 2006, when I moved to the university of Massachusetts with Ajay Wakhloo, who's a world renowned neurointerventionalist. And so, we built that center together, and the center has really taken off in a sense that we were just, again, very good fortune. That a stroke and mechanical thrombectomy has fundamentally changed the space to becoming a major intervention, and so with that good fortune comes the resources that are necessary to do multidisciplinary world-class research.

(1) Optimal Thrombectomy Technique and Equipment

[Dr. Michael Barraza]:
All right. So both of you have clearly played an integral role in the evolution of optimal stroke therapy, and so the question is today, what do we consider optimal in terms of technique and equipment and doing stroke thrombectomy? So you guys shared your background, and I'm going to share my own. I'm trained as a body interventional radiologist, and I picked up stroke thrombectomy in practice after my formal IR training. I was initially trained by neurosurgeons, followed by neuro IR, and then more body interventionalist. And I learned with stent retrievers first, specifically the solitaire, and then it changed practices. As you know, the vast majority of these were done with aspiration first with the penumbra system, and more recently with imperative care zoom catheters, which Dr. Gounis is familiar with having published a paper on the efficacy of those. They're fantastic catheters, but the point of all this is that I didn't really notice any difference in terms of efficacy in technical or clinical success between these two different systems, and I don’t know if that’s anecdotal, but it's really not just me. And, you know, we have all these case series and trials with catchy names (my favorite being the BADASS technique, CAPTIVE, and SAVE), and they all propose some combination of stent retrievers, balloon guides, and aspiration catheters as the best way to remove clot. But to me, it seems like there's no real convincing data that establishes any of these is superior. Do you guys agree or am I missing something?

[Dr. Hannes Nordmeyer]:
So I think we're still struggling with the most effective method to pull clots, right? So, we tried out anything: pure stent retriever in combination with balloon guiding catheters, double stent retriever techniques, SAVE techniques, pure aspiration. And I had the fortune to work with René Chapot for many years, and we went for double retriever techniques. Really in the early years of thrombectomy, when we failed to retrieve the clot within the first two or three maneuvers, we deploy two stent retrievers in parallel to untangle the clot in between of them. And we had really high success rates with that, and, yes, I think nowadays, the need is really to have one retriever that makes it all, right?

[Dr. Michael Barraza]:
I'm with you.

[Dr. Matthew Gounis]:
I can elaborate a little bit on that, in that, I think at estimate, we had the good fortune to hear the SWIFT DIRECT study. And what I took away from that is that it was really compelling that up to 97% of successful recanalization, which is defined as TICI 2b/3. So the techniques and the equipment have gotten remarkably good. I think we need to change the definition of success, which is what Dr. Nordmeyer just said, and that should be first pass TICI 2c/3 because that's what we know is going to impart the greatest benefit to the patient.

[Dr. Michael Barraza]:
Yeah, I think that's a really important point. Dr. Nordmeyer, for a standard large vessel occlusion what is your normal setup in terms of equipment?

[Dr. Hannes Nordmeyer]:
We have mainly two setups. In patients with straight cervical vessels, we go for balloon guide catheter and a stent retriever technique. If there is any anatomical reason, like extremely torturous ICA, where a balloon guiding really doesn't make any sense because aspirating from below, with all the vasculature distal to it, having been stretched and being in a ventral position, doesn't make sense. We go for a triaxial access with a guiding catheter, aspiration catheter, and the microcatheter for the stent retriever. So, this is mainly the approach for easy and difficult anatomical situations, and then it's really up to the location of the thrombus and the behavior of clot within the first one or two maneuvers, whether to change the method or to go on with the stent retrieving approach.

[Dr. Michael Barraza]:
Do you do most of these from femoral access?

[Dr. Hannes Nordmeyer]:
Yes, mainly yes, and the posterior circulation also radial or brachial access. But, I would say more than 95% of our cases, we're doing by a femoral access.

(2) Future Thrombectomy Technologies and Factors for Success

[Dr. Michael Barraza]:
Same with me. Are either of you aware of any techniques or equipment on the horizon that looked like they could distinguish themselves over the rest?

[Dr. Matthew Gounis]:
Yeah, I'd be happy to respond to that one. There’s a new series of aspiration catheters that are very, very large bore, like 088 aspiration systems. And I think the newest technology that we're evaluating and it’s in its beginning in terms of clinical experience with the millipede catheter being tested in Ireland and the route 92 catheter being tested in the United States. I think that reliable navigation of these super large bore catheters to the middle cerebral artery is going to be realized in the near future. And I think, again, it's lending us towards what I said as the definition of success, which is TICI 2c/3 at the first pass.

[Dr. Michael Barraza]:
Yeah, I'm with you. I think that's really important to establish that. I think there is a big difference between a 2b and a c. I wish all that stroke thrombectomies were TICI 3. Those are probably the most gratifying procedure that I do. But, everybody who does these or studies them is familiar with what we're talking about. The challenging ones: the clot that doesn't budge after multiple passes or the artery that shuts down right after you open it up. On the other hand, those are one of the most frustrating things that I do. And I think it's really important to ask what makes them challenging or unsuccessful. Dr. Gounis, you and I had talked about this earlier. You published a really insightful review in the Journal of Biomechanics that highlighted four main factors that influenced thrombectomy success. For our listeners it is titled, “A Clinical Perspective on Endovascular Stroke Treatment Biomechanics,” and it breaks down strokes thrombectomies to four factors that contribute to success. It's factors related to the blood vessel, factors related to thrombus, factors related to technique and tools and operator related tools. And I'd like you to focus for a second, if you wouldn't mind, on those first two factors. You've also published on vascular histopathology and clot composition and stroke, including differences in clot composition based on the number of passes needed for retrieval. Dr. Gounis, what have we learned about underlying vascular pathology and clot composition, and how they affect the likelihood of technical success and thrombectomy?

(3) Stent Retrievers vs Aspiration Catheters

[Dr. Matthew Gounis]:
So, first of all, I can't take credit for all that work. I'm just a co-author with a lot of really amazing people. That's another thing I've been fortunate about in my career is to work with some of the best people in the world, including Dr. Nordmeyer, but that specific reference is really largely attributed to Charles Majoie and his group in Amsterdam. But, I thought it was a very thoughtful approach to looking at thrombectomy, and what we've learned in today's existing technology, forgoing what is to come, is that the success of the procedure relied largely on the composition of the embolus, the thing that occludes the vessel. And so, it's been shown that groups in Germany, the collaborations like the STRIP registry, that clots that have a lot of fiber (they're typically from cryptogenic strokes or from a cardio embolic source), essentially the stent retriever or an aspiration catheter, can't get them. And it's because with a stent retriever, there's less integration with this tough fibrin structure, so that's the way stent retrievers work is by kind of acting like a cheese grater and getting some of the clot in the interstices of the device. So that as you pull it, you have mechanical clamping of the clot, and if you don't get that integration, what happens is the clot simply rolls off the stent. That's why it was really an interesting analysis from the STRATIS that they found longer, stent retrievers are more effective, and it's just because you're giving the clot less opportunity to completely roll off the stent. With aspiration catheters, you can't get adequate ingestion if it's very fragrant rich, so you can't get adequate amounts of clot into the catheter, so that when you pull it, you can't get the entire clot out. So that's these fibrin rich clots are kind of like the tough clots, and it’s probably around, Dr. Nord Meyer can clarify, 20% of the time. That's why with today's existing technology, like different stent retrievers, I have a different mechanism of action, like a Nimbus type device. We've shown that with the technique Dr. Nordmeyer invented, which is kind of to pin the clot with the microcatheter and the Nimbus device, what we've shown in vitro studies doing high resolution CT is that there's less relaxation, or loss of integration, with the stent retriever and using a technique like that.

(4) Nimbus Device vs Standard Stent Retriever

[Dr. Michael Barraza]:
In terms of design, is the Nimbus any different from a standard stent retriever?

[Dr. Matthew Gounis]:
Yes, it's fundamentally different. So, it's got a unique series of angles on the proximal end that are smaller in diameter. It has a stronger radial force. and so, yes, it's fundamentally a different concept and that's why it's probably working better with these fibrin rich clots. I don't know if Dr. Nordmeyer would like to elaborate.

[Dr. Hannes Nordmeyer]:
Yes, it's really impressive to see the Nimbus device acting in a model with a fibrin rich clot, where you can see under camera guidance, how the proximal spiral part of the device grips the clot and, really, pinches the clot while the struts close if you resheath it a little bit by advancing the microcatheter over the proximal part of the device. And we've seen that in the lab. And then we really felt that in real life in patients, it worked the same way. So whenever we found that the clot was fibrin rich, just by pulling out tiny fibrin, rich white or yellow fragments, or just by getting the feeling that the clot is not reacting to a stent retriever, we switched to Nimbus and performed this pinching maneuver and really had high success rates.

(5) Intravascular Imaging: Optical CT and IVUS

[Dr. Michael Barraza]:
That's interesting. Yeah. I look forward to seeing this. So we've talked about being able to identify these fibrin clots based on how they look. Dr. Gounis, you've also done a lot of research on intravascular imaging. With either optical CT or even more traditional like IVUS, can you tell if that, clot composition or anything from them, before we start trying to remove these clots, which ones are going to be harder to pull?

[Dr. Matthew Gounis]:
Yes, so, we've looked into it. So just to be clear, the existing optical coherence tomography technology that's clinically available and the existing IVUS systems are really not designed and not appropriate for intracranial use, so anything beyond the carotid siphon. You'll see scattered case reports of OCT being used in the intradural space, but nothing ever distal to the siphon, and the reason is because of the tortuosity. Those catheters, essentially the fiber that spins the lens, it can't work in that extreme tortuosity, but we are introducing a new neurovascular technology that'll be available probably within a year. It's a very exciting system. It's basically an 014 wire that has the optical engine in it. And we have looked into it, and I think it's going to be primarily useful in the setting of stroke when you have multiple failed passes, and it's not a tough clot, but rather there's an underlying atheroma or a dissection. That's where I think this technology may be particularly useful is to look at those underlying vascular etiologies that are not cardioembolic or large artery, generated emboli.

[Dr. Michael Barraza]:
Yeah, that's actually really exciting. Talking about peripheral arteries and even veins, using IVUS has completely changed how we look at some of these vessels. I can imagine that would be a really huge thing in the head. Dr. Nordmeyer, what other tactical or patient specific elements can result in a challenging or unsuccessful thrombectomy?

[Dr. Hannes Nordmeyer]:
As I said, anatomy is really an issue. So if we have very tortuous vessels, like an elongated and one segment that is really dipping downwards and then pointing upwards again, we know that all techniques available on the market have a high percentage of failure in these occlusions. So if the anatomy is against us, there's still really the need to go again and again and again for the retrieval and to escalate the therapy by switching to a more aggressive device that has higher radial force or another architecture like the Nimbus or to go for double retriever techniques and really trying to advance a large bore aspiration catheter as close to the thrombus as possible to apply as much aspiration force to the thrombus as you can. But I think what Dr. Gounis just said thrombus imaging with an 014 wire is giving us some information on whether there's atheroma or just tough a clot, for example, that could be a real game changer. So if we're having had four or five or six unsuccessful passes, and we know that the reason for it is the atheroma, we would straight go for stenting, of course. So it still might be very challenging to get up a PTA balloon up there in torturous anatomy, but having early information on the reason of the occlusion that can accelerate the whole procedure and prevent us from spending time on several thrombectomy maneuvers, if we know that stenting and angioplasty would be the right thing to do.

(6) Angioplasty and Antiaggregation Regimen

[Dr. Michael Barraza]:
Are you routinely doing angioplasty and stents for intracranial atherosclerotic lesions?

[Dr. Hannes Nordmeyer]:
Yes, we do. We do quite a lot of them, and we are going more and more towards early stenting in the angioplasty. If we fail to recanalize a vessel group with all our techniques, because we know that it's always better to keep the vessel patent and put the patient to some risk with aggressive antiaggregation, then to leave the vessel closed.

[Dr. Michael Barraza]:
I'm with you.

[Dr. Hannes Nordmeyer]:
So even if we're not sure that it is an intracranial atherosclerotic disease that we're treating, but maybe we're just treating a tough clot that we are unable to remove, it's better to stent a tough clot than to leave the vessel closed.

[Dr. Michael Barraza]:
Okay.

[Dr. Matthew Gounis]:
Can I follow up with a question to Dr. Nordmeyer: in that setting where you have to do a bailout stenting, first of all, what materials are you using? And secondly, what kind of antiaggregation algorithm are you applying?

[Dr. Hannes Nordmeyer]:
We mainly use the NeuroSpeed double lumen PTA balloon together with a CREDO, a self-expanding, intracranial stent. Now we're also using the heparin coated CREDO stent, which was a very early evaluation phase. The CREDO stent has to be oversized. So if you're dealing with a two millimeter MCA, you would go for a three millimeter stent, and you have to make sure that the overlap, distal and proximal, to the stenosis is enough because at the ends, the stent has less radial force than the central part. So typically we're going for a three by 20 or three by 50 in stents, depending on the length of stenosis, and we underdilate by at least 10 to 20%. So we wouldn't go for a three millimeter angioplasty balloon and the three millimeter vessel, but we would take a 2.5 millimeter balloon, especially in the perforator bearing segments, like M1 V4 basilar artery and not occlude perforators and cause the so-called “snow-plowing” effect to push atheroma into the perforators.

[Dr. Michael Barraza]:
Dr. Gounis had mentioned the antiaggregation regimen that you use. What are you guys doing?

[Dr. Hannes Nordmeyer]:
We apply GP IIB/IIIa antagonist, like tirofiban or eptifibatide right before placing the stent. So sometimes, if the stenosis is really looking difficult and dangerous, we do PTA first, do a run, exclude vessel rupture bleeding, and then, give the bolus of the GP IIB/IIIa antagonist, and then deploy the stent. And then we go for a flat-detector CT or DYNA-CT or whatever it's called depending on the manufacturer, exclude bleeding and add IV aspirin, which is available in Germany, not in all countries unfortunately. But I really like to add IV aspirin because in case of any interruptions of the aggrastat, so that tirofiban perfusion, like patient transport for diagnostic or whatever or just a doctor or a nurse who forgets to change it and to keep it running, can lead to early in stent thrombosis. So the aspirin might give a better protection together with the other IV medication. And then as early as possible, we switch to a double antiplatelet regime, but this is routinely done next day after a CT control after exclusion of a huge infarct, ablating.

(7) P2Y12 Inhibitors and Incidence of Intracranial Bleeds

[Dr. Matthew Gounis]:
And I think there's a lot of exciting research around using P2Y12 inhibitors, like cangrelor that have a very short half-life. The cardiologists have a lot of experience with it, and I think more and more groups are investigating that as kind of a bridge to the traditional dual anti-platelet therapy.

[Dr. Hannes Nordmeyer]:
Yes, I'm sure it is, but it's also dangerous because it has a half-life of only a few minutes, right? So if you stop cangrelor, the effect is gone all of a sudden, and that's a specific risk, especially in big stroke teams where you have a new team members every couple of months. And, yes, so that's the only reason why I'm a bit afraid of cangrelor.

[Dr. Michael Barraza]:
Does it seem like there's any increase in the incidence of intracranial bleeds after using these? These patients are already at risk of bleeding anyway.

[Dr. Hannes Nordmeyer]:
No, actually not. So that's what the data also shows it's usually around 10%, and there are no randomized studies on acute intracranial stenting in the setting of thrombectomy procedures. But, what we know about is that we help patients, and we don't cause many more bleedings then usually. There are also studies who showed that with stenting and double anti-platelet regimen, we have less bleedings than not to stent and have the vessel closed.

[Dr. Michael Barraza]:
It's exciting.

[Dr. Hannes Nordmeyer]:
Yes, it's paradox in a way, but it makes sense because the brain stays healthy and it's not going to bleed late.

(8) When to Stop Making Passes

[Dr. Michael Barraza]:
This is not something I'm currently doing, and for me, it would be a great option to have kind of a bailout technique when I get to these cases where this clot just won't budge, no matter what I do. One of the things that I struggle with is knowing when to stop when you've made several passes, in particular, where I struggle is where I see just a little bit of improvement with each pass, just enough to keep going, but never open up the vessel entirely. Or when you've opened it up, and then it just shuts down immediately. Now, Dr. Nordmeyer, what is your end point in these cases where you have trouble opening these up?

[Dr. Hannes Nordmeyer]:
I can tell when to stop. It depends so much on the whole setting. So if it's a young person and the time window is good, and there were no early infarct signs at the beginning of the procedure, it's very hard to stop and say, so now this patient is going to have a huge MCA infarct. So, I almost never stop before getting a reasonable recanalization, even if it's stenting and angioplasty at the end.

[Dr. Matthew Gounis]:
And just to add to that, I think, there's a lot of advancements in imaging in the angio suite, both Siemens and Philips now have these CT trajectories that are saddled trajectories. And, what that gives you is much better. It's almost like looking at a multi detector CT. So I'm curious in the future, and it just has to be studied, but that if rather than having a time metric as when to stop, have that informed by a non-con and CTA. That might be an option.

[Dr. Michael Barraza]:
Yes, I think that the system you're talking about (the intravascular imaging) could be really useful in these cases is knowing when you're dealing with an intracranial stenosis or dissection, rather than just a hard clot. I think that could really be useful in guiding your management.

[Dr. Matthew Gounis]:
I hope so. We need more data to say that conclusively, but that's the hope.

(9) Post-procedural Management and Thrombectomy Safety

[Dr. Michael Barraza]:
Yeah, I'm with you. Talking about post-procedural management in these patients. Forget where I am, we use the TICI score to guide blood pressure parameter control, but I wonder if the patient with intracranial stenosis, who's going to require like five passes, might not respond the same way as a young patient with atrial fibrillation, he throws a soft clot. I don’t know. I mean, should we be looking at these patients differently? Should we be managing them differently? I think from a pathologic standpoint, these are very different types of patients. I mean, these lesions are very different.

[Dr. Hannes Nordmeyer]:
The ones with intracranial stenosis?

[Dr. Michael Barraza]:
Yes, and just the challenging ones in general, the ones that are going to take five, six passes to remove rather than one and done.

[Dr. Hannes Nordmeyer]:
I think you have to keep in mind that the cerebral autoregulation and patients with intracranial stenosis have already changed a long time before the intervention, before the acute occlusion of the vessel segment. So you really have to keep the blood pressure as low as reasonable. That doesn't mean 80 systolic, but it means that you have to keep an eye on them, not to have the blood pressure during the first couple of days above 120 or 140, and really not allow them to have any peaks in blood pressure because these vessels are really not used to high perfusion pressure. So the same in extracranial carotid artery stenting, where we know that these reperfusion bleedings or hyperperfusion syndromes occur, especially in patients who have a very, very poor perfusion before. So with a little mismatch and bad collateral, they are at a high risk of re bleeding or late onset bleeding after a couple of days.

[Dr. Matthew Gounis]:
And just to add to what Dr. Nordmeyer has said, which I think is really important, is regarding the time metrics. These patients have been suffering, as he said, for many years. It's a gradual process, and there are data that there’s angiogenesis that has been occurring, and there's a lot more collateralization in the distal vascular territory, so that may change the time metric in which to treat as well.

[Dr. Michael Barraza]:
Okay, you pretty much already covered all the other questions I had, so what else is important to cover that I didn't go through in terms of these challenging cases?

[Dr. Hannes Nordmeyer]:
I think time is something, that we really do have to keep in mind because there is no reason to exclude any patient from any revascularization procedure if there are no huge early infarct signs. So if you have someone who's fluctuating with us clinical symptoms and showing up one or two days later and deteriorating all of a sudden, there is still a good reason to go for revascularization. Of course, there is no reason to go for IV lysis because there is a significant risk of intracranial hemorrhage. But opening the vessel is still very safe, even in the very, very late time window, and we know that from DEFUSE 3 and DAWN data. But we already had patients where we open up one segment after two or three days now.

[Dr. Matthew Gounis]:
Yes, I'd like to add to that. I just got back from SVIN in Phoenix, and Thanh Nguyen, a professor here at Boston University, had a fabulous paper that she published in JAMA neurology that’s not a randomized controlled clinical trial, so that means it's not level 1A evidence, but their data suggests that the non-con CT and a CTA are as sufficient for these late window patients as advanced imaging. So advanced imaging should not be a barrier to revascularization in the late window. And I think that, like Dr. Nordmeyer said, probably the most fascinating thing is how incredibly safe mechanical thrombectomy is in all the trials that we have. So it's probably always better to open the vessel rather than not. And I would like to say the really exciting thing in the future, we already have the ESCAPE-NA1 trial, which unfortunately did not meet its primary end point, but we have the ESCAPE-NEXT trial, which I think will be successful in showing that really the future is going to be, not just in mechanical thrombectomy, but now shifting gears towards brain protection and in brain therapy to give patients, first of all, the most opportunity to get a successful reperfusion. So maybe delaying the penumbra, but also reducing cytotoxic and vasogenic edema post-procedure. I think these are really exciting technologies that, coupled with mechanical thrombectomy, will be a very good solution.

[Dr. Michael Barraza]:
That is exciting. I look forward to reading that, and I look forward to all of the research that we routinely see from both of you. Thank you both for taking the time to do this. Is there anything else that you guys want to cover?

[Dr. Hannes Nordmeyer]:
I think that's it.

[Dr. Michael Barraza]:
All right.

[Dr. Matthew Gounis]:
Thank you so much.

[Dr. Hannes Nordmeyer]:
Thank you very much.

Podcast Contributors

Dr. Matt Gounis

Dr. Matt Gounis is a biomedical engineering professor at the University of Massachusetts Medical School.

Dr. Hannes Nordmeyer

Dr. Hannes Nordmeyer is an interventional neuroradiologist in Germany.

Dr. Michael Barraza

Dr. Michael Barraza is a practicing interventional radiologist (and all around great guy) with Radiology Associates in Baton Rouge, LA.

Cite This Podcast

BackTable, LLC (Producer). (2022, January 10). Ep. 178 – Challenging Stroke Thrombectomies with Tough Clot [Audio podcast]. Retrieved from https://www.backtable.com

Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.