Melanie Cole, MS (Host): Welcome to UAB MedCast. I'm Melanie Cole. We have a panel thought leader conversation for you today with Dr. Elizabeth Liptrap. She's a Neuroendovascular and Vascular Neurosurgeon and an Assistant Professor at UAB Medicine. And Dr. Mark Harrigan, he's an Endovascular Neurosurgeon and a Professor of Neurosurgery at UAB Medicine.

And they're here to highlight some state of the art management of carotid disease for us today. Doctors, thank you so much for joining us. And Dr. Harrigan, I'd like to start with you. How has the understanding of the medical management of carotid disease evolved over the years? What are you seeing in the trends for risk awareness? Tell us what's going on right now.

Mark Harrigan, MD: So there's been a lot of change in the management of carotid disease. So to begin with, carotid stenosis caused by atherosclerosis is a very important disease in our society. Carotid stenosis accounts for about 20 percent of all ischemic strokes, and we are identifying more and more people with asymptomatic carotid stenosis as well.

So management of carotid stenosis has had a sea change in its evolution over the last couple of decades. And at this point in history, I can tell you that there are two essential elements of the management of carotid stenosis. The first one is, optimal medical management, which is focused on optimizing risk factors for atherosclerosis.

So this would be state of the art blood pressure control, for example, lipid management, diabetes management, smoking cessation, and so forth. So that's medical management of carotid stenosis. And the exciting thing about what's going on with carotid disease these days is that we now have three different interventions.

So the first pillar of carotid disease management, of course, is medical therapy. The other essential element is an intervention. And so, the tried and true intervention for decades has been carotid endarterectomy, which is extremely effective. I do that myself. I've done more than 250 endarterectomies over the years, but it's got its drawbacks, it's invasive compared to the other techniques.

And not all patients can tolerate that very well. Two newer techniques that have been less established but are now established are carotid stenting in which a catheter's inserted in the artery in the leg, and a balloon, and then a stent is placed in the carotid artery. And then more recently there's a hybrid form, which is a combination of stenting and open surgery.

So, the exciting new thing that's happened in the last several months is that in recognition of accumulating data to support the safety and efficacy of the less invasive techniques, that is, carotid stenting and this hybrid surgery, the Center for Medicaid Services, Medicaid and Medicare Services, recently announced an important change, they recognize the safety and value of the two alternatives to open surgery, and as of last October, they are now providing reimbursement for both carotid stenting and transcarotid artery revascularization.

And that's for asymptomatic selected patients as well as symptomatic, selected patients. This reflects two developments. One is that the scientific evidence has now shown that, carotid stenting and TCAR, that's the hybrid procedure, are equal to surgery in terms of safety and efficacy. And also, surgeons and interventionalists can get reimbursed from Medicare for doing those procedures.

Host: Thank you so much for that overview, Dr. Harrigan. And Dr. Liptrap, in your opinion, I'd like you to expand on some of the key considerations when deciding between the different therapies that Dr. Harrigan mentioned and treatment modalities. Speak a little bit about patient selection and shared decision making and how these therapies come about.

Elizabeth Liptrap. MD: I think as Dr. Harrigan had stated previously, the cornerstone of any treatment of a patient with carotid stenosis is medical management, and again, that would include cholesterol, and lipid management with medication and diet and exercise, diabetes management, smoking cessation, and other things. And if those have not worked have been deemed inadequate, then we can move on to carotid revascularization.

And so, as Dr. Harrigan had stated, there are three different options. The first one being carotid endarterectomy. And what that involves is the patient is usually placed under general anesthesia, although some people do that under moderate sedation, and it involves making an incision in the neck and going down to the carotid artery, taking out the plaque that's there, and then placing a graft in that space and then closing the artery.

And so that surgery is, you know, one that has been used forever and it's great, but for some patients it may not be the right thing to do if they have had radiation in the past, for instance, to the neck that might make it difficult to do the surgery and put them at higher risk.

If the plaque is higher up in the neck, it might be difficult to access the top of the plaque. And other anatomical considerations, might make a patient more favorable for the other two interventions that Dr. Harrigan discussed, which are, transfemoral carotid stenting or the transcarotid arterial revascularization. And so with the transfemoral carotid stenting, a patient will go to our angiosuite, and they would be placed under moderate sedation, and then we would go through the femoral artery, which is in the leg, travel up through the aorta into the carotid artery in the neck, and then place a stent that way.

And that is also a safe and very effective procedure. The transcarotid arterial revascularization, that bypasses going through femoral artery in the leg and traveling up through the aorta in the abdomen and the chest. And we go directly into the carotid, in the neck. And so for that, a patient would be placed under general anesthesia, and then we would localize the carotid artery and we would make a small incision in the neck, go down to the carotid artery, and then place the stent that way, through the plaque.

Mark Harrigan, MD: I'd like to add a few things. So, as Dr. Liptrap, described, there are three completely separate techniques for revascularization. And each approach for revascularization has advantages and disadvantages, and for any individual patient, we can select what we feel is the best approach.

For example, a patient with a very heavily calcified plaque with circumferential calcification, patients like that are not good candidates for any sort of stenting procedures, whether it's traditional transfemoral stenting or TCAR, because the ring of calcium impedes the placement of a balloon and a stent.

And so those are good candidates for open surgery. Alternatively, patients who are very medically sick or frail, those are subjects, that are pretty good targets for awake procedure with transfemoral carotid stenting. The TCAR technique is the newest of the three techniques.

It's only been on the scene for eight or 10 years, and it's got an aspect to the technique that probably is the best protection against embolization during the procedure, in that we actually literally reverse flow in the carotid system temporarily occlude antigrade flow in the common carotid artery, and cycle the blood through a series of tubes and a filter back into the venous system via the femoral vein.

So this reversal flow technique, which TCAR employs, is thought to be extremely effective protection against embolization and a stroke during the actual procedure. But then again, some people can't have TCAR. So for example, some patients have dense calcification of the common carotid artery, which precludes safe insertion of the sheath in the carotid artery in the neck.

So the point I'm making is that all three techniques have been shown to be valid and safe and efficacious, and we can highly individualize selection of the technique to the patient.

Host: What an exciting time in your field, doctors, and Dr. Harrigan, can you discuss the importance of having this robust care team when treating patients with carotid diseases? How is the introduction of therapy that involves multiple subspecialists and the utilization of a multidisciplinary team been so ideal for managing complex patients?

Mark Harrigan, MD: So, at UAB, the Neurovascular service, which is in the department of Neurosurgery, that includes Dr. Liptrap and me, we work very closely with the UAB Stroke Neurology Service. We have a very close relationship and we make many of our decisions in the management of carotid disease patients by consensus and by joint discussion.

We have a weekly multidisciplinary conference where we review cases and we get input from all involved, both experts, neurology, vascular neurology experts among the stroke neurologists and the cerebrovascular neurosurgeons. So, we're very proud of this system that we have here because it enables us to apply a very robust decision making process to each patient.

Host: Dr. Liptrap, are there any promising emerging therapies, technologies in the field of carotid disease management that you're finding particularly exciting? You all have discussed three techniques that are very exciting, especially the hybrid form, but anything else you'd like to mention that's really exciting right now?

Elizabeth Liptrap. MD: I think, the aspect of TCAR that Dr. Harrigan discussed with reversal flow as a means of preventing emboli during the stenting process, is really exciting and innovative and it's possible that we could also apply that to transfemoral stenting, as well to potentially, decrease the risk of emboli, with that technique.

That's not something that's, currently done. We use special wires with a filter on them to catch emboli in both the transfemoral stenting and the transcarotid stenting techniques. But the reversal flow, I think we could potentially apply to the transfemoral one as well. I don't know if you had any other exciting innovations, Dr. Harrigan.

Mark Harrigan, MD: Yeah, I'd like to mention asymptomatic carotid stenosis. So asymptomatic carotid stenosis, means patients who have never had a stroke or a TIA attributable to the carotid plaque. And so, there has been a growing body of scientific evidence to allow us to determine which of those patients with asymptomatic plaques are at higher risk of stroke compared to lower risk patients.

And so, this could involve for example, studying, radiographic studies of the plaque itself to look for possible ulceration or intraplaque hemorrhage. Those patients would be at higher risk. We also know from medical evidence that patients that demonstrate progression, significant progression of their stenosis over a short interval are at higher risk of having a stroke.

So some patients remain clinically silent and without a stroke or a TIA for years and years and other patients are at higher risk. So, using various techniques, we are enabling ourselves to pick out the patients with carotid stenosis that are asymptomatic that are at the highest risk. And then lastly, I want to mention that we are approaching the completion of a major nationwide NIH sponsored randomized clinical trial called CREST 2.

This is an 83 million dollar major randomized trial, including only patients with asymptomatic stenosis, that are randomized to either intervention or no intervention. And, we're also looking at transfemoral stenting and endarterectomy in that study. We hope to complete enrollment of the 2,400 plus subjects this year. And, that will help inform us about natural history and risk and optimal patient selection for the various techniques. So, exciting time to take care of patients with carotid stenosis.

Host: Well, it certainly is, and I thank you both so much for giving us this overview, and it is such an exciting time. Fascinating information. Thank you both for sharing your time and expertise with us today. And for more information, please visit our website at uabmedicine.org/physician. That concludes this episode of UAB MedCast.

For updates on the latest medical advancements, breakthroughs, and research, follow us on your social channels. I'm Melanie Cole. Thanks so much for joining us today.