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BackTable / VI / Article
Complicated Intracranial Stenosis Treatment: How to Maximize Success
Gabrielle Gard • Updated Mar 6, 2022 • 38 hits
When facing a complicated case of intracranial stenosis, should recanalization be attempted even if the procedure seems unlikely to be successful? Due to the safety of treatment, even for complicated intracranial stenosis cases, many operators now recommend intervention and aggressive post-procedural management.
Dr. Hannes Nordmeyer, head of the Neurointerventional Department at the St. Lukas Hospital in Solingen with radprax, and Dr. Matthew Gounis, director and co-founder of the New England Stroke Center, discuss the nuances of complicated intracranial stenosis cases and explain why they recommend revascularization even during “late time window” thrombectomy cases. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable Brief
• For intracranial stenosis cases with atherosclerotic lesions, it is better to attempt to keep the vessel patent through stenting or aggressive antiaggregation than to leave it stenosed.
• Citing the DEFUSE 3 and DAWN data, Dr. Nordmeyer suggests that even in late time window clot cases, mechanical thrombectomy is still safe and that revascularization should not be excluded from the stroke intervention armamentarium.
• For challenging intracranial stenosis cases that require several passes, post-procedural management of blood pressure is crucial to avoid re-bleeding or late onset bleeding.
Image provided by Dr. Sabeen Dhand.
Table of Contents
(1) Intracranial Stenosis: To Open or Not to Open?
(2) Techniques for Late Time Window Clots
(3) Post-Procedural Management of Challenging Intracranial Stenosis Cases
Intracranial Stenosis: To Open or Not to Open?
In treating complicated intracranial stenosis cases, especially intracranial atherosclerotic lesions, there is some uncertainty whether it is best to attempt to open the vessel or to leave it closed. However, Dr. Nordmeyer and Dr. Gounis recommend that it is always better to keep the vessel patent and take on the risk with aggressive antiaggregation than to leave a closed vessel. For these intracranial stenosis cases with atherosclerotic lesions, Dr. Nordmeyer discusses using a self-expanding intracranial stent (CREDO) that must be oversized to avoid pushing the atheroma into the perforators. In addition to this, Dr. Nordmeyer may also use a GP IIB/IIIa antagonist or IV aspirin for especially difficult intracranial stenosis cases.
[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. 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. 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.
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Techniques for Late Time Window Clots
Even in “late time window” clots, Dr. Nordmeyer and Dr. Gounis recommend that revascularization should not be excluded, stating that mechanical thrombectomy is still very safe in these scenarios, and non-contrast CT and CTA are sufficient imaging modalities. However, it’s common for operators to get stuck on tough clots, and it's often ambiguous when pass attempts should be stopped.
[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.
[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 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.
Post-Procedural Management of Challenging Intracranial Stenosis Cases
Successful post-procedural management is crucial; however, what this entails can differ greatly between patients. Dr. Nordmeyer and Dr. Gounis share their approach considerations in properly managing these patients during post-procedure. One of their key considerations is to keep the blood pressure below 120 or 140 to prevent re-bleeding or late onset bleeding since patients with challenging intracranial stenosis typically have vessels that are sensitive to high perfusion pressure.
[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.
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.
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