Melanie Cole, MS (Host): Welcome to AHN Med Talks, an informative resource for physicians across various specialties as we delve into the latest medical insights and best practices, ensuring you stay at the forefront of your field.

I'm Melanie Cole. And today, our discussion focuses on the AHN endovascular procedures. Joining me is Dr. Evan Luther. He's a neurosurgeon at the AHN Neuroscience Institute, where he serves as the Chief of Vascular Neurosurgery and Co-director of Endovascular services. Dr. Luther, it's such a pleasure to have you join us today. Give us a little bit of an overview, as we get into this, of AHN endovascular procedures and their significance in neurovascular interventions today.

Evan Luther, MD: Absolutely. Thank you, Melanie, for having me. It's a really broad subject. But I think, for most people, in the last five to 10 years, when they think of endovascular procedures in the Neurosurgery realm or Neurology realm, I think most people think of stroke interventions. And that's because it's vastly changed in the last decade or so after many positive trials have come out that essentially showed that mechanical thrombectomy for acute ischemic stroke in large vessel occlusions is one of the most beneficial procedures we can do in medicine. In general, many people think that that's a lot of what we do. And in fact, it is quite a big part of what we do in the neuroendovascular realm. But there's many more things that we do, and I think we're going to kind of delve into some of those other topics, especially the ones that have really come into light in the last several years and have changed kind of drastically what I do in my practice and what others in the neuro IR realm also do.

Melanie Cole, MS: I find that so interesting because you're right, the intersection of cardio and neuro, really mechanical thrombectomy kind of cemented that. And you're right, a lot of people associate that when they think of neuroendovascular. So, tell us a little bit about what you're doing at the AHN Neuroscience Institute, the services that you offer and some of the procedures that we're talking about here today.

Evan Luther, MD: Absolutely. So, as we mentioned, we're the comprehensive stroke center in the age and network here at Allegheny General Hospital. So obviously, that means that all of the acute ischemic strokes that require thrombectomy get filtered into us. And so, we're doing quite a number of those. But those are kind of the emergency procedures that come in, day in and day out. But I think the other flip side of that is there's been kind of a drastic shift, I think, in the last 10 to 15 years as well in terms of treatment of aneurysms, so brain aneurysms, especially those unruptured aneurysms, so those patients, you know, who are getting elective treatments for aneurysms.

And I think the technologies for treatments of these aneurysms has vastly changed. Many aneurysms that previously would only be treated via microsurgery, which requires a big incision on the patient's head, not without some pretty significant risk to the patient, can now really all be treated endovascularly, almost in an outpatient setting, meaning that the patient's come in, they get the procedure done, and then they leave the next day. They only have a small puncture site on their wrist or their leg. So, that has changed drastically in the last several years. And I think it's pretty impressive that we're able to offer those things to patients.

One of the things that is familiar to most neurointerventionalists, but is probably less familiar in the community is technologies that we refer to as flow diversion. And what that means is that many of them are stents which are placed into the artery where patients have aneurysms, and it essentially blocks flow of the blood into the aneurysm over time. And these aneurysms that previously would require the large craniotomies or open surgeries for treatment, now essentially we place one stent inside the artery, and within six months, the aneurysm has gone away. So, it really takes all of that rupture risk for those patients off the table in a very minimally invasive procedure.

Melanie Cole, MS: Isn't that fascinating? What you're doing and the tools in your toolbox now. And as we think of integrating the surgical and endovascular techniques, expand on some of the other conditions. You've talked about aneurysms and the difference between open and endovascular technique. But why don't you tell us a little bit about carotid stenosis and embolization and some of the other things that are really exciting that you're doing.

Evan Luther, MD: Absolutely. So, I think carotid stenosis is one of these conditions that affects many people. We see a lot of that here. And I think, previously, and this kind of filters into that same kind of open surgery versus endovascular treatments, and 30, 40 years ago, everyone was getting what's called a carotid endarterectomy, which means that they were essentially having an incision on the neck and actually opening the artery to remove the plaque for these patients who have, you know, symptomatic carotid stenosis. And over the years, they developed what's called carotid stenting, which is very similar to what we talked about with the aneurysms in which we go in through the blood vessels of either the wrist or the leg and deploy a stent within the artery to open up that narrowing that's causing the symptoms of stroke or things like that. Again, it's a pretty minimally invasive procedure in terms of what we do.

And I think this is one of those that sometimes endarterectomy is still the right answer for the patient. It's really an evaluation on a case by case basis, but it's certainly very helpful to be able to offer carotid stenting as an alternative to endarterectomy for these patients. Because often, stenting makes the most sense for them, for each individual.

The other things that I think are really important to kind of discuss and I think have changed my practice recently is that, in the last year, this is what's called middle meningeal artery embolization for subdural hematomas. So, I think anyone in the medical community has almost certainly had dealt with a patient who has had a subdural hematoma at some point, meaning even those patients who had an asymptomatic subdural hematoma that didn't need anything, I'm sure even primary care doctors have seen them, what we found is that in 2024, there were three randomized controlled trials that all showed that for patients that required surgery for chronic subdural hematomas, that's essentially a blood clot sitting on the surface of the brain, that causes pressure on the brain and can lead to significant symptoms for those patients that required surgery for evacuation of the hematoma. If we go into what's called the middle meningeal artery, which is a small artery on the covering of the brain, and we block that artery off those patients, it reduces their risk of recurrence of the hematoma by about threefold. That's kind of the biggest risk after the evacuation, is many times these hematomas can recur requiring reoperation.

So, we're talking about a threefold decrease in risk of reoperation for these patients, if they undergo a middle meningeal artery embolization. And one of the trials actually also showed that for patients who were relatively asymptomatic. If you did a middle meningeal artery embolization kind of almost prophylactically, that reduced their rates of requiring an intervention later on, meaning a surgery or something like that. So, it actually reduced their need for further treatment later on if they did the middle meningeal artery embolization almost prophylactically, if that makes sense.

So, there's going to be more to come on that end, but I think a really fascinating thing because physiologically, this is something that we really didn't even understand that the middle meninge already contributed to these subdural hematomas until recently, and now it's become almost standard of care to treat many of these patients with that procedure.

Melanie Cole, MS: Dr. Luther speak about the role of multidisciplinary collaboration and the role that that plays in optimizing these outcomes for the patients that are undergoing AHN endovascular procedures.

Evan Luther, MD: one of the important things from my perspective is that our endovascular services, I'm the only dual trained neurosurgeon in our department, which means that I was trained in the neurointerventional realm as well as open surgery. But my partners in the endovascular realm, one is a neurologist and the other two are radiologists.

So, I think that we have a really good collaboration with one another and are really able to discuss patients and choose the right treatment for each individual patient based on what that patient needs, if that makes sense. And I think that kind of collaboration, not just within the neuro IR realm, but also within AHN as a whole, being able to collaborate with other neurologists, internal medicine doctors, radiologists across the board really helps us do the right thing for each patient that comes through our doors.

Melanie Cole, MS: This is so interesting, Dr. Luther, and it's such an exciting time in your field. What advancements or innovations in AHN procedures are on the horizon? How do you envision these shaping future neurovascular care? Looking ahead, tell us about research priorities in the field of AHN endovascular procedures.

Evan Luther, MD: Absolutely. You know, so my goal my background has been in what's called intravascular imaging. So, that's kind of, I think, on the horizon for neurointerventional procedures, is really understanding what's actually happening within the vessel when you're doing these things. 

From what we do in an interventional realm, essentially is that we take x-rays while we inject dye into the blood vessels. So, you can understand that that's a actually a pretty crude evaluation of what's going on within the blood vessel. I think within the next 10 years, we're going to be evaluating the blood vessels from the inside using very small catheters with imaging techniques that allow us to understand what's really going on inside the blood vessel rather than what's happening on the outside, if that makes sense. The reason I bring that up is that that's something that cardiology has been doing for a long time. You know, they've had intravascular ultrasound and even techniques called optical coherence tomography, which is a laser light analog to ultrasound for evaluating the inside of the arteries. And they've been doing it for a while. But I think in the neurovascular realm, that's something that's going to really take off. And that's something that I really wanted to spearhead and pioneer here at AHN and to really bring us at the forefront of the field.

Melanie Cole, MS: Well, you certainly are, and thank you so much Dr. Luther, for such an enlightening conversation. Really an exciting time. Thank you again for joining us and sharing your incredible expertise for other providers today. And to learn more or to refer your patient to Dr. Luther, please call 844-MD-REFER, or you can visit ahn.org. Thank you so much for listening to this edition of AHN Med Talks with the Allegheny Health Network. I'm Melanie Cole. Thanks so much for joining us today.