Current and future embolization

Episode Transcript

Thank you. Hello, this is Chris Molvar. I’m in an elaborate, pretty fancy soundproof booth at the Cook Medical booth at the SIR annual meeting in sunny Phoenix, Arizona. I’m joined by a recent friend and colleague, Ron Winniker. On this podcast, we’ll chat all things embolization, including its current role in our practice and insights into its continued evolution. By way of introduction, I’m an interventional radiologist in the Chicago suburbs at Loyola University Medical Center. My practice is focused on interventional oncology and portal hypertension, and certainly embolization in its varied forms is embedded in the mentioned subspecialty work, along with everyday work at an academic medical center. In many ways, embolization is how I keep the lights on at home. My practice leans far more towards eliminating blood flow rather than improving blood flow. That’s kind of a basic introduction. I’m going to leave it to you, Ron, to introduce yourself and your practice.

Thanks so much, Chris. It’s really fun being here in this booth. And we’re here at the SIR annual meeting and, you know, we’re going to—like Chris was just saying—we’re going to talk through all aspects of embolization and how it’s evolved over the years and how it’s evolved in each of our practices. As a little bit of background about me, I’m also an interventional radiologist. I’ve been kind of in the academic side of interventional radiology my entire career. I’ve spent part of my time early in my career at Weill Cornell Medicine in New York City doing full spectrum of IR practice, and then went to Thomas Jefferson University in Philadelphia, where I continued to do general IR practice and kind of focusing on venous disease specifically. And now, recently in the last six months, I’ve returned back to, to Weill Cornell in New York City and leading our superficial vein practice, but, you know, doing all aspects of venous disease, as well as general interventional radiology.

So—fun for us to talk about embolization and all the different components of embolization and how they vary across all the different practices that we do and different types of procedures that we do. And obviously the embolic device that we use, the embolic technique that we use, varies from case to case. And so maybe, Chris, we can get started kind of how we approach a specific situation. And whenever we’re in an angio suite and we’re, let’s say on a call case and the patient’s relatively stable, but we see some sort of extravasation that we need to get our catheters out to and deal with embolization—how do you deal with the idea of how quickly you get there and just deal with the problem versus being timely, thoughtful, and kind of addressing every possible vessel that’s in there?

Yeah, yeah, I agree. I I think this certainly is a common balance you gotta strike, especially in the call setting where you’ve got, on one side, being fastidious, quick. And on the other side you’ve got the elegance of, how deliberate can that embolization be, how targeted it can be. How much can you limit adverse events and achieve an outcome, you know? And there are certainly, you know—the different product categories kind of lend itself to, is this a pure speed scenario like trauma, like bleeding, like extravasation?And then, where are you? You’re in the pelvis, gelfoams, great. It’s sort of a no—it doesn’t take a lot of thought to do it. I don’t cut those pieces of gelfoam into cubes, I tear it. It makes its way through a three-way stopcock, and then it’s a, you know, proximal infusion. Do I use a microcatheter? Yeah. Most of the time. But do you need it? Maybe not. It’s more of a dead space issue or it’s just I’m so used to it that you do it, but it’s quick.

Yeah. And it’s interesting. We all do it differently. Like you tear it. And everybody’s got their own approach. I take mine and I cut them in nice small cubes, and I get it in there and I have six ccs of contrast, and I have a very specific cocktail that I make that’s not too dense, that’s going to be able to be injectable, that’s not going to include my microcatheter when I’m working. So it sounds like, you know, we all do this a little differently,

Right. And I’m for sure a little more haphazard. I’m finding 10 ccs rather than six ccs. And you know, if I’m trying to get a little deliberate with it, do I leave that stopcock in its 90 degree position or will I put it with that aperture somewhat closed and now harder to push across? Maybe that gelfoam is turning into smaller pieces. But the speed there, and the desire to have that person outside of the IR suite for their continued resuscitation is sort of, you know, a big portion of how you make that decision. Could you be more elegant? Could you get closer to that bleeding? Could you treat it with a coil? Probably, but do you want to spend time to do it? Do you have the time to spend? Things that you often don’t know the answer to. And so, you know, in that situation, I lean towards speed and a bit of a carpet bomb. You know, you’re not particularly deliberate, but that outcome is in part driven by that speed, sacrificing elegance.

Yeah. I think it’s—for me at least, it’s pretty common in the pelvic trauma situation. Exactly what you’re saying, if I have an unstable patient, I know I have extravasation, I know I have pelvic trauma I’m dealing with, I’m going to get into the internal and I’m going to start gel-foaming and try to get things under control, get their blood pressure under control, get their heart rate under control, and do it quickly. Sometimes I do see that they’ll branch into multiple branches and—let’s say it’s a postpartum patient and all of a sudden there’s a small vessel going to the labial area and you don’t necessarily want to gel-foam the entire location in that particular circumstance. And you see one feeding vessel clearly there. Maybe that’s when you can—and they’re stable enough, obviously, you have the luxury of time—you can get down there and put one coil pack and just occlude that one vessel and occlude that one area of bleeding.

Yeah, completely agree. You know, and if something looks very linear, there’s an obvious pseudoaneurysm, and you can pick out anterior/posterior division and it looks straightforward catheterization, yeah, that is also—it’s tempting. It’s not as though, oh, you know, a coil embolization is particularly slow. It’s just not as fast as gelfoam or it’s some combination thereof. Some gelfoam, maybe that takes the pressure head off, especially patient doing okay than a more complete embolization utilizing coils to bridge a known site of injury. Certainly quite tempting. And then sparing one division, where you figure you’re limiting adverse events, but not eating up too much time to do it, you know. And I find it—it’s always—even the monitors that you got in a room and that ticking noise that you hear the heart rate, it’s so sort of background/subconscious when it’s at an expected heart rate—that sort of background, you know, each time you get that signal on an EKG—but when it changes and that heart is beating faster, or you pick up some pulse ox alarm, there is like a—oh, you know, an instinctive reaction to that, that sort of changes the cadence of the way you’re moving through that procedure. And it’s like that audible feature that, you know, you don’t hear it when it’s normal. It’s like background expected noise, I can’t hear it. But once it changes or that patient is decompensating, the way those alarms, they like—they’re right—they’re wired into your cortex.

It’s such an important piece of information that we try to train our trainees to learn that exact skill.

Yeah.

I think it’s part of our process of education. It’s part of being an interventional radiologist and being aware and managing your room. We have great nursing staff. You know the nurses are after—but sometimes they’re doing other paperwork, they’re distracted. And so I agree with you having that kind of gut reaction, gut instinct to heart rate and everything that’s going on in the room is part of our job and part of our role. And it does make us more efficient managing our patients and saving lives, which is a big piece of what we do.

Yeah, right. And if that monitor didn’t have an audible signal, it would be a lot harder for me to pay attention to it. When it’s a number on a screen, especially if the screen—you’re not looking at it, it’s hard to know. But you get that auditory feedback, it can be a clue that doesn’t interrupt really what you’re doing. It happens. It’s sort of there and ever-present and you don’t need to interrupt the task at hand to pick up on a change. So it’s—I don’t know, it’s one of those “never thought about it till you step back a little bit” and—you put an outsider in that room and they’re like, you know, what is the din of this room? And a lot of that din is the monitors and—you know, along with the sort of expected chit chat and the opening up of products, but—and paying attention to those things compared to just blinders on, focused on the image, I think is how you drive an improvement in outcome and how you figure out this speed versus elegance balance.

Yeah. And going after that speed versus elegance, we talked about pelvic trauma a lot. What do you think? You know, we deal with renal trauma, we deal with hepatic trauma cases and injury, we deal with splenic trauma and injury, we deal with left gastric artery embolization.

Yeah.

I guess I’ll let you kind of open it and I can say some other things, but, you know, thinking about those different anatomies, how do you deal with them differently than the pelvis?

Yeah, they’re solid organs—CTs certainly an important part of how you’re going to guide an intervention. And so creative injury—I don’t have those things sort of fresh in my mind. What I care about is, is there a blush, right? And almost agnostic to the grade of liver, spleen, kidney, it is, is there extravasation? There’s your roadmap, and then it’s a matter of taking that roadmap, and with that in mind you, you sort of—before these cases start, you’ve got a general idea about how selective, how segmental is that treatment going to be as compared to a more global therapy. So, you know, solid organs, that doesn’t lean heavy on gelfoam for me. The temporary nature, you know, at least the expected, recanalization of gelfoam-treated vessels, I’m not so sure that always happens in small solid organs, that that vessel doesn’t have flow for seven to 14 days. And my sense is it doesn’t come back looking just like it did. And so that idea of, this is evanescent, this is—you know, I’m going to be able to treat the injury with a resorbable embolic that in a month will leave me with a patent vessel. I’m not so sure.

Not really in the way we do it. I feel like we’ve created an occlusive coil pack and we do it distally, and it probably is more permanent than we think. There is necrosis. I’ve seen scans afterwards too.

With gelfoam, right?

With gelfoam.

Yeah, infarction of that tissue, no blood flow for a week, I mean, I think that often happens and with that infarct, you get remodeling and that vessel may not return as you expect it, that it may return as a collateral. And, you know, so not—I don’t lean heavy towards a gelfoam embolization in that setting. That’s where coils are probably first thought, as part of, you know, does this need a bridging embolization or not? Kidneys, like that’s convenient. And arteries, like it’s simple. You just follow the arborization and find a place to put a coil, and you’re not worried about that backdoor perfusion.

Yeah.

You know, liver, a bit tougher. You gotta worry about it. And then maybe it is a mix of get the catheter—you know, if you can’t get it beyond a site of injury, a little gelfoam for the distal portion of it, and then coil, sort of on the, you know, so to speak, front door. That—I don’t know, that sort of hasn’t failed me all that much, you know? And spleens another—how do you unpack that? And do you bother with, you know, embolizations that are beyond the hilum of the spleen, targeting injuries? Or is this a pressure head reduction proximal embolization with, I don’t know, whatever your favorite device is? And I’m interested with what you’ve got to say, and then I’ll give you sort of my somewhat-pessimistic thinking about splenic arteries and mid-splenic artery embolization.

Yeah, I wonder if we’re on the same page with this, because—so splenic arteries I think are a bit confusing. We have this comfort level, and in the education pathway and the teaching and the training of interventional radiology across the board, there’s always a lot of confidence in saying, just go ahead and do proximal embolization, takes the pressure ahead away—

mm-hmm.

—and then whatever’s bleeding is going to stop and it’s going to thrombose on its own and these patients are going to do great.

Yeah.

I’d like to believe that that is true. I’ve had those cases not truly work in that way for a number of reasons. One is, there’s a lot of blood flow in the splenic artery, and sometimes you try to place those coils, and I’ve seen—thankfully, not in my hands necessarily—but I’ve seen coil migrations, that they’re initially placed and they just shoot out straight into the distal spleen.

And they’re not really accomplishing the goal that you’re setting out to do. I think dorsal pancreatic arteries can be a little bit hard to identify, especially in these traumatic situations where you might have an unstable patient. And so it’s not always clear, it’s not always definitive, oh, this is dorsal pancreatic and I’m preserving the collateral blood flow that I want to preserve. In my mind, if—the way I kind of segment it I think is—relatively stable, splenic rupture trauma patient—if I see one or two segmental branches that I can get into that are clear sources of extra, or the clear area that’s correlating to the CT hematomas, I’ll get into each one of those and maybe coil them individually and then work my way out. And I’m preserving a lot more spleen by doing that potentially.

Yep.

And, you know, I’ll use gelfoam sometimes around those coils as well to close those areas. But if it’s the full spleen, if I know that I’m going to have to get into every segment top to bottom, and there’s no possible way that I’m going to have the time to individually coil each branch, then I will do that kind of right after the dorsal pancreatic, put a nice coil pack. But I’ll be, you know, careful as to how I put that in. Make sure it’s occlusive, make sure it’s stable, make sure it’s stagnant, make sure I’m oversizing well enough that it’s going to stay in that position when we’re doing the embolization.

Yeah. Yeah, I’m probably with you on that threshold, finding two hilar vessels, very reasonable. That’s usually pretty quick. Yeah, the splenic artery can get tortuous. The robust flow can make it hard to image, but I think that’s often, you know—so to speak—the juice is worth the squeeze, to get out there. And yeah, you’re probably going to infarct that tissue that you end up with a coil at the hilum or beyond that the ability to collateralize around that is limited, but it’s not large portions of the spleen. They’re already injured. They may already be infarcted, and you know, seemingly you’re putting your finger closer to the leak. My pessimism is mid-splenic artery, and it’s a cosmetic pessimism. You’re describing about coil packs traveling on you, that to me is almost the norm. That this idea that you can create a perfect-looking slinky spiral in the mid-splenic artery is sort of science fiction.

Now, you want to go plugs, I get it. I think that’s—

Plugs work great.

That’s the way—but you know, can you get a plug there? And then, yeah, it’s a hassle. I don’t—I’m not often thinking plug. And if the artery’s big enough to put a five French catheter there, well, usually the plug that’ll go through that is too small. But, you know, you got vendor-specific devices meant for splenic artery occlusion, and routinely for me, they don’t deliver the cosmetic result. Now, does it matter? I don’t think so. And so I often will take either pushable or detachable coil that you try to form there and you futs with it a couple times thinking, can you start to get that spiral configuration? And when it doesn’t, I just let the giant little tail go out to the splenic hilum, and it—there’s the backstop. And then with that—it’s cosmetically, like—you know, you’re not proud of it.

You know, I’m not that—Like that’s—but my signature is going to look far more like, oh, look at that little slinky going out to the splenic hilum. And then you’ve got an opportunity with that as a backstop closer to the mid-splenic artery to actually form that coil pack. But that—I am rarely able to achieve that sort of expected, pretty—there’s a plug sitting in the mid-splenic artery and there is no cosmetically displeasing portion of that. I am almost always—and sometimes it’s even—you know, you face that sort of—you got lucky. That thing is forming perfectly—two, three coils, you put the fourth one and the whole thing shoots, and you’re like, ah. Right?

That’s the worst one, when it’s not the first one. And all the—you know, you think you’re doing it perfectly. You see it’s stable and it’s sitting there and it’s not going anywhere. And like you said, you put that third one in and it’s just, the pressure goes at that point.

There it goes, right? Something changed, that now the whole thing is in the hilum and you know, you got to do a bit more work. So I almost intentionally will take the—give me an oversized coil, I know it will form a kind of sinusoidal-looking path out to the hilum, it’ll bump into something and then I’ll be able to at least get some scaffolding to then build that more dense coil pack.

I think plugs, as you were talking about though, are really a place where our world is changing.

Mm-hmm.

I think the use of plugs is increasing. There seems to be more and more of them coming on the market that we’re utilizing.

Yeah.

And it may be the—especially in splenics, it may be the intro spot. You put a plug there, you create that backstop that you’re looking for.

Yeah.

And then the coils go right behind it. Because the plug itself may not be enough.

Right.

Usually you do need to pack some coils into that to really create a full occlusion. But that seems to be, at least I’m seeing, a good way forward.

I hope so. Right. And it’s just, it’s a sizing issue. And then the tortuosity issue. I’m probably a bit flexible too on upper gut perfusion that—I’m of the belief that it is incredibly hard to infarct the pancreas, to injure the stomach in an ischemic way that—you know, where’s the dorsal pancreatic? Where’s the pancreatic of magna? I’m like, eh, I don’t—I’m kind of agnostic to it. You look more for, well, here’s a bit of tortuosity. Can I take advantage of the tortuosity? Be just at that spot, as maybe that’s an anchor, and maybe that’s going to give me this cosmetic result. And I—there is so much plasticity to perfusion in the upper abdomen that I think—I get you want to follow a textbook description of it—look for it, you know, important. But, the likelihood of meaningful pancreatic ischemia, I think there’s a lot of room to play with.

It’d be interesting if somebody was going to do—could do a retrospective study looking at that exact piece of data.

Yeah.

Because you’re right, the body collateralize in an incredible way.

Yeah.

We think that that’s probably the best collateral to leave in place, but I agree with you. There probably are other collaterals that’ll just take over that flow. And truthfully, even if the whole—if we embolize and the whole spleen’s necrotic, alright, a good percentage of those are going to have an infection.

Mm-hmm. ,

And maybe they’re going to need, you know, splenectomy in the future, but in the end, you’re going to save their life. You’re going to do the job. It’s going to b— it’s going to accomplish the goal.

Yeah.

And if they need a surgery down the road when they’re stable, well that’s okay. That’s part of our job in the IR space, I think.

Yeah. You know, and sometimes you get lucky, upper pole branches tend to come early. Sparing the upper pole I think can help with some symptomatology, especially pleuritic pain and—yeah, and often in traumatic settings, like sometimes that spleen is so trashed due to falling off the ladder that yeah, the embolization isn’t helping it, but how much is that versus this recovery was always going to involve a lot of splenic infarct. So I—you know, I don’t know. It certainly—the way people practice there, there’s a lot of opinion guiding things.

So I have a question for you. You said a lot of your practice is outside of the trauma space.

Mm-hmm.

And you do IO and interventional oncology and hepatic and Y-90 type cases. So how does that differ as far as your embolic goals and how you approach this when you’re doing Y-90?

Yeah, I mean, probably the bulk of my interventional oncology practice is radioembolization. I would consider my shop to be a catheter shop. We are not an ablation shop. Elegant ablations, several tumors in tough locations—it’s just, ah, I’m not that interested. I’d rather solve that problem with the catheter, and take advantage—and most of my work here is with HCC, so I’m taking advantage of that hypervascular tumor. And, you know, the radio embolic product I use, the intent is minimal embolization. In fact, you deliver your glass radio embolic angiogram before and after, and I’ll tell you, they—it looks identical. So it’s about a delivery mechanism, not about ischemia. And I think some of that is—it’s beneficial. Like the radiation therapy, the bulk of its activity comes from reactive oxygen species generation, not the beta particle itself, ripping breaks in DNA. But those reactive oxygen species that then may be some propagation and more damage to DNA tumor can’t be repaired.

And then, you know, you’re chasing the outcome. And then, you know, these are things where I meet these people in street clothes. Trauma patients, I’m never meeting them in street clothes.

No.

And yeah, the intent is they’re going home. And so a little different than chemoembolization where yeah, you are chasing an embolic goal, you’ve got an angiographic target. Are you getting to this, you know, sort of five beat stasis like you might pursue in a fibroid? Similar idea, you know, there is—yeah I do it with a lipiodole aqueous chemotherapy emulsion, and then close the door with an embolic. And here now, you know, we’re in the micro embolic space with particles, you know, spherical particles, PVA, as part of an increased dwell time of that embolic—of that chemo—prevent the washout by reducing the pressure head. And then, you know, the ischemic injury that, again, you know, you want to substitute gelfoam as a more cost effective—how do you, you know—and even some of the, you know, initial studies decades ago now, yeah, it was gelfoam, and so—in a certainly different pace to that case, where it is deliberate, you’re looking for extra hepatic perfusion, you care a lot about, is that right gastric nearby? Is the GDA nearby? Where, in trauma, those things just—they don’t drift top of mind at all.

Yeah. And are you routinely still coiling all of those, or—

No.

You’re not. You’re just treating directly with the Y-90?

Yeah.

Because I know they’ve taken that—a lot of people have taken that out of their practice.

Yeah. I’d say my likelihood of coiling an extra hepatic vessel is somewhere, you know, under 5%, and probably closer to two. It’s really unlikely. Smaller microcatheters help. Comfort with product helps, knowing you don’t need to be much more than a centimeter or two beyond that non-target vessel as long as you got flow. And, you know, where do a lot of your adverse events come in these radioembolization planning? It is the attempt to shut these vessels down. That—you know, that catheterization injures the vessel, or you’re unhappy with the position of that coil, or, you know, the coil is simply not occlusive. And so what you think leaves you with a, “There will be no flow beyond this,” is actually not true. So almost always it is a—I’d rather split a dose and give two, rather than give one dose proximal and require embolization and then need to trust that that embolic is occlusive to flow or occlusive to that, you know, that yttrium bead.

So, yeah I—you know, it touches on an interesting—I don’t know, we talked spleen—sort of interested in GDA and not in the pre Y-90 mapping, but do you do empiric embolization of the GDA? Does that sort of fit the practice mold? An endoscopist tells you there’s bleeding, distal stomach, proximal duodenum—is that good enough? Is that enough to say, I don’t care if there’s extravasation here, right? So a little different than the sort of trauma, critical ulcer disease, upper gut bleeding, GDA territory. Do you say goodbye to it empirically?

That’s a great question, and I’ve approached it so many times over in the clinical setting and in day-to-day practice. My general reaction is yes, I think we can take away the GDA with pretty much no fear of complication. The collateral flow is going to—is going to get around there. We’re not really worried about it. We can take the GDA basically whenever we want without much risk to the patient. And it’s a nice place to embolize. It’s a relatively straightforward vessel to catheterize. We can get our microcatheter out there. Our coil pack isn’t going to embolize somewhere we don’t want it to. It seems to—

mm-hmm.

—stay where we’re going, unlike the splenic embolizations that we deal with.

Yeah.

And so in general, yeah, in the trauma setting, completely. There’s no doubt that, you know, there’s extra—you’re going in, you’re putting a coil pack in, you’re taking the GDA.

Yeah.

And then in these others, I—when it’s—they’ve been hospitalized for a while, they’re intermittently bleeding, there’s no extra, but they see an ulcer there—

Mm-hmm.

I go ahead and do coil it.

Yeah.

The hard part that I’ve come across and the questions I’ve been asked a lot by people early in their careers is, how much of it do you embolize? Where do you start? How distal do you go? And how far back do you go?

Yeah.

So do you have a—what do you do in those cases?

I’ll give you my opinion there. And it’s usually—I’ll start at the gastroepiploic, you get some tortuosity there that is a nice anchor for a coil. And agree, the arborization here leaves you with the—the cosmetic results are going to be what you want. These are—these are pretty good territories for trainees, especially the initial coils. I think the last coil deserves some attention as to, where are you putting it? How close to the ostium do you want to get? And my workaround has also been that I use gelfoam sandwich. So it’s that distal coil that gets sort of occlusive, but then it’s a bit of gelfoam slurry that gives me some penetration into these smaller branches where, you know, that’s likely the source of the hemorrhage. But I’m not spending the time to catheterize them, I’m simply embedding a bit of gelfoam slurry there.

And then I do—most of the time—carry the embolization to as close to the origin as I can get with comfort. And I think it’s that last coil, it sort of lends itself to the discussion of, you know, where do you use detachables? That’s a good place for a detachable coil because, you know, you lose a pushable coil in the hepatic artery, eh, I mean it’s probably not of consequence. Can your ego take it or is your ego going to drive you to go find a microsnare and get that catheter out, or get that coil out? So, you know, it’s always that last coil question in the GDA that—I do try to get close to the origin. I feel like some of the gelfoam slurry, you can even, you know—as that gets fairly occlusive, some of that, you know, ending up near the ostium, you spill a little gelfoam into the hepatic artery, it’s in the, “eh, no big deal” category, but you hate to re-intervene. Where, if it’s some of those proximal branches that are the source of ulcer perfusion, you know, you’d like to take that pressure head off. So am I okay with a sub-centimeter gap? Yeah, no problem. I don’t need to be flush. But will I leave two centimeters and feel like I did a good job? No.

So I’lI probably disagree a little. So I don’t use gelfoam much in this territory. I’ll maybe deploy some coils, pull back, maybe do an injection,—

Mm-hmm.

—see if it’s occlusive. If I don’t see occlusion, I’ll probably just take more coil and make a more occlusive coil pack.

Oh yeah.

And keep working that back and keep checking with venography or arteriograms to make sure that there’s no flow getting through that coil pack that we’ve completely occluded that vessel—

—and there aren’t big collaterals that we need to see. If I do see big collaterals, then I just keep tracking further back.

Yeah.

And I probably will leave about one or two centimeters. I won’t get super close, because I am worried about it—

—coming back and that final coil will definitely be a detachable coil for me.

Mm-hmm. .

Because I’m worried about losing that coil and the last thing I want to deal with is exactly the situation you just described—

Yeah.

—of a coil that gets into the hepatic artery and goes out there. And like you said, does it matter? Do we need it? Do we need to go chase and get that out? Probably not. It’s probably not going to cause a large clinically significant problem, but it just doesn’t feel right to me to leave that coil there and not go after it and not chase it. And then you’re, you know, getting small snares out there and that’s a tough case. So I’d rather just avoid that situation altogether and maybe leave a little more GDA at the top—

Mm-hmm. .

—as long as it’s not feeding in anywhere bleeding. Which it almost never is. I think you can leave that.

Yeah. Your first coil’s pushable, or is that detachable? Because you know you’re going to use it at the top. You know, do you—is that the first one too? Because it’s just, well I’m going to use this platform at some point, why don’t I just start with it and end with it?

I like that the most. That’s been my clinical practice. Maybe it’s just the way I was trained and people—we all have different inputs from so many different places.

Yeah.

And a lot of our stop points of how we do things are maybe challenges that we observed over time. But I like the start and end of a detachable coil. Because I know that first coil’s going to go exactly where I want. Then you can fire coils in the middle of whatever type. You can shoot them in with saline, you don’t even have to push them in.

Yeah.

And then when you’re getting close to the top and you’re getting close to anywhere where that coil could get into trouble, that’s when I go back to detachable coils.

Yeah. And I think that’s an interesting sort of, “Would you rather?”What do you do with that pushable coil? Would you rather use a coil pusher or would you rather do a hydrostatic delivery?

Depends on the anatomy.

Yeah.

Depends on what the risks are for me.

Yeah.

GDA I’ll do—I’ll do the hydrostatic version.

Yeah.

Most everywhere else I want to push it in and I want control.

Yeah. I am—I would probably give you a very similar answer, that there is movement of the catheter tip with hydrostatic deliveries. Sometimes, you know, you can end up delivering it and you’re not sure if you delivered it and you know—so you could be a little—got this back-table problem solving that like—shoot, did that coil come out or not? That you just don’t face that with a pushable coil that you’re using a wire to push it out.

But it is exceptionally fun, I will tell you, to take a syringe and just flush it in and shoots out and forms all instantaneous. It’s really nice to watch.

I agree. When you’re in a scenario that you could do that, it’s great, and it’s speedy, right? And this idea of how much metal can you get in there quickly and wow these detachable coils are so long. I don’t know. You start doing hydrostatic delivery of pushable coils, you can really keep pace and well, you got the fiber advantage there too.

Yeah. I will say though, you know I mentioned my practice is very hyper-focused and moving in the venous direction. I do a lot of ovarian vein embolization and that’s somewhere where the embolization rate of coils is a bit higher. And where it’s embolizing to—we’re in the venous system, so if that migrates into the renal vein, it’s going to instantaneously shoot through the IVC, go straight out into the pulmonary circulation, and now you have a pulmonary artery coil that—hey that’s tough to get out.

Yeah.

And you have to go chase it.

Yeah.

You can’t just leave that there. And so in those situations, I have a larger safety margin and I’ll use detachable coils there a lot more. I know a lot of people use pushable coils. I use a balloon occlusion catheter and detachable coils and I take a lot of control on where those coils are going because I want—the same way we do in an artery, I want complete occlusion in those veins because that’s the only way you’re taking the pressure away from the pelvis.

Yeah. Do you use a sclerosant and if you do, do you have a recipe? Are you—oh it’s just the standard to, sorry, foam—or you’re putting gelfoam in there and making toothpaste? Or you’ve got your own brand of, you know—what do you do with a sclerosant? Do you need it or is it just the macro embolic—or is it a combination—when you’re dealing with pelvic varicosities?

I think it is important to treat the pelvic reservoir.

Mm-hmm

The varicosities in the pelvis are the source of the patient’s pain. And even if we take the pressure away, yes those may shrink, but they’re still there. And just like any other varicosity that you’re dealing with, it’s connected in the body and it’s going to recruit blood from somewhere else. So I do think sclerosants important in pelvic venous disease. I think you have to treat the pelvic reservoir of varices.

Mm-hmm .

So sclerosants great there. I use Tony Van Brooks’s cocktail. He taught me this and told me about this a long time ago, and so I’ve kept that cocktail forever. And—

Yeah, what’s that?

It’s 16 ccs of contrast, four ccs of 3% sotradecol, and half a brick of gelfoam.

Okay.

And I mix it up and it makes a nice liquid, but stagnant, embolic. So you inject that and it often does not cross across to the contralateral side or exit through the internals. You can fill that entire reservoir of veins and allow it to dwell and do its job. And so it seems to work well. I think you can use any mixture.

Yeah.

I don’t think there’s one perfect cocktail. So that’s my habit, but anybody can use anything in the reservoir. And then you do have to coil on your way out. I think sclerosant alone won’t work.

You can’t see that mixture, so is it displacement then of a contrast column that you know how much to inject, or it is a—I put a catheter in and, you know, here’s how much I had to squirt in of dye to see the pelvic reservoir, and then that guides how much of that you squish in there?

Well I’m using—I use contrast in mine.

Oh contrast, okay.

I use contrast so you can see it.

Got it.

Which makes it better. Because otherwise I have no idea how you know. You can—

So it’s contrast—

Contrast, sotradecol, and gelfoam.

Got it. Got it.

Yeah.

I was thinking—I had propiodol in my mind, thinking if you didn’t say propiodol, you can’t see it. And is this foam? That’s not foam, that’s more toothpaste.

Yeah, it is a little bit of a foam because of the gelfoam. I leave the air in those little—the gel—the gelfoam that I’m putting in. But it—so it is somewhere in the middle.

Yeah.

I think you can use any mixture. So thinking about that going forward, as far as the perfect embolic, what—Looking forward 10 years into the future, where are we—where are we evolving to? What’s our next-gen embolic? Is glue going to take over?

That’s my belief. Or it’s some combination thereof. I think it’s pretty potent to use a macro embolic like a coil, pushable/detachable, as a scaffold, and then build upon that with a liquid embolic, rather than this concept of metal density—liquid metal. Packing coils? I—for me that’s like, well why not just use a liquid that’s going to find those spaces and—nothing’s going to pack denser than a liquid. Now you know, it’s got the learning curve of how do you use it, where do you use it, you know, and it’s not always combination. But the speed of a liquid embolic is quite enticing, agnostic to the patient’s coagulation system. And the—there is a, depending on how you use it, you can blend a sort of macro versus micro embolic, you know. Flow directed, it is tough. It’s pretty unpredictable. But you’re filling smaller branches, as compared to, give it a coil to stick to, and then, you know, you know the goal there is, it sticks and then fills the gaps, so that, you know, you limit your recanalization rates. And I think, histologically, recanalization rates after coil embolization, they’re probably quite high. They just—they don’t really matter because the injury’s healed. And you know, are these angiographically visible? Maybe not, but can a pathologist find a channel through a coil pack? Like, probably.

Probably.

You know, does it matter—like in the brain—it matters a lot, right? You’ve re-profused that aneurysm because there wasn’t enough packing density. Well now your rupture risk is higher. But often in our space, I don’t think we have those same concerns, and recanalization can be okay.

Yeah. How do you make the glue? Because that’s always hard. What ratio do you use?

Yeah. And I’ll tell you—to make it easy—because I don’t use NBCA, I use Onyx. So I use the DMSO-based and—you know, it’s time on a shaker and then I—the different liquid consistencies, I’m not so sure in my hands I can tell a difference. 34,18? It’s all about the same. And you know—so there is nothing in terms of prep, there is no ion-free table. But you know, you gotta flush the catheter with DMSO. People stink after you do these embolizations.

For sure.

DMSO can be quite stimulating depending on where you are. So it’s one of those, you get ready, a little extra anesthesia, then the DMSO infusion.

And you feel like you can control and get into pretty much any vessel out there and fill the whole network, that you’re not just doing too-proximal an embolization and leaving all of it behind.

Yeah. Flow directed with liquid is tough, and it’s tough because it’s hard to predict, that I don’t really count on it. If I need that sort of penetration, but, you know, I’m not going to bother catheterizing a lot of small segmental branches. Potentially it’s a bit of gelfoam, slow the flow, pack that into these sort of, you know, near-ish capillary leve,l and then with that slowed flow there comes your more expensive liquid. Limit the amount of liquid you need and then, you know, you’re sort of controlling the level of embolization just based on flow kinetics. I don’t know, I’m interested in, where do you take things in a decade, you know? What do you think we’ve got beyond the existing toolkit? Or, you know, are we creating training gaps that, if a lot of practices lean towards detachable coils—like now a sort of blind spot, let’s say, is liquid. Like a lot of people aren’t trained on it, so you’re learning it after training. Isn’t that, it’s not approved in the periphery. But you know, is the—are we going to have a blind spot with pushable coils if, you know, the detachable coil sort of reigns heavy in practice-utilization, not trained on it, and so am I going to pick up a pushable coil, use it for the first time in a new job?

I think we’re going to see a lot of that. I think the practice patterns have fully shifted.

Yeah.

Detachable coils and plugs are the primary tools that are being used in every training program around the country right now. At least my experience—

Yeah.

—at a couple of different places. Glue is the biggest limiter, because we don’t use it enough, because it’s not approved in every location, and we don’t have easy access to using that glue, and cost is a challenge. And so that seems like the future, if I were to predict where we’re going, liquid embolic just seems more controlled.

Mm-hmm

It seems like we can achieve our goals in a clear way of getting all the branch vessels rather than just putting a plug in centrally and hoping it depressurizes enough to solve our problem. So it does seem like we’re getting more selective, we’re getting less—leaving less material inside the body and leaving less foreign objects behind. So it does seem like that’s probably where we’re going.

Yeah. And then, you know, it’s kind of—maybe we’ll just get better at—how do you image afterwards. That tantalum is so dense, you put these people in CT scanners, there’s so much artifact. If you’re betting that in an aneurism, I don’t know how you tell. Are you doing it—

Well, coils are just as bad.

Right? Yeah. Right. Because you, you’re going to—you know, is the MR the solution? Well no, because now you’re going to get artifact from that coil in an MR scanner. Contrast enhanced ultrasound, right? That is some pretty niche expertise too.

Yeah. I think we’re hitting the end of our time here. So this—this was absolutely wonderful. Chris, I really enjoyed talking to you about embolization. Seems like we ran the whole gamut from top to bottom.

Yeah.

As far as different types of procedures, arterial, venus technologies that are coming in the future. So this was a lot of fun. Thanks.

Yeah. Pleasure sitting on the other side of the table, you know, in a semi-private booth getting to have, you know, a pretty friendly discussion.

Yeah.

Thanks, this was great.