BackTable / VI / Podcast / Transcript #289

Podcast Transcript: Treating Clot in Transit

with Dr. Rehan Quadri

In this episode, host Dr. Michael Barraza interviews Dr. Rehan Quadri, interventional radiologist, about the definition, indications and techniques for treating clot in transit. You can read the full transcript below and listen to this episode here on BackTable.com.

(1) Defining Clot in Transit

(2) Detection and Diagnosis of Clot in Transit

(3) Integrating Clot in Transit into Existing Clinical Thromboembolism Algorithms

(4) Treating Clot in Transit: Lessons Learned in Dr. Quadri’s First Case

(5) Clot in Transit in Patients with Shunts

(6) Clot in Transit with Concurrent Pulmonary Embolisms

(7) Dr. Quadri’s Most Challenging Clot in Transit Case: a Brief Case Study

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[Dr. Michael Barraza]
Welcome to The BackTable Podcast, your source for all things intravascular or, otherwise, minimally invasive. You can find all previous episodes of the podcast on iTunes, Spotify, or backtable.com. Subscribe to the podcast, leave us a review, or reach out to us on Twitter or email to let us know how we can make this a more valuable resource for the endovascular community.

[Dr. Michael Barraza]
This is Michael Barraza returning as your host. I'm joined by Dr. Rehan Quadri at UT Southwestern Medical Center. Thanks for joining us, man.

[Dr. Rehan Quadri]
Yes, thanks for having me. I'm excited to talk about thrombectomy.

[Dr. Michael Barraza]
Yes, we're going to talk about thrombectomy and specifically, treating clot in transit, but before we start doing that, I want to hear a little bit about UT Southwestern. It's interview season right now and a lot of our listeners are trainees, and so I'm hoping you can tell us a little bit about the training program at UT Southwestern.

[Dr. Rehan Quadri]
At the moment right now, we have, well, I guess four IR/DR and two independent - two to four per year. Everybody rotates at three different hospitals. There's the main hospital at Clements, there's Parkland Hospital, the traditional trainee location, and then Children's as well. For the most part, I would say the volume is very spread across the entire board of cases from biliary to transplant. We get some aortic and PAD work, obviously not as much as we'd like, but we do have a good relationship with vascular surgery. We do a lot of wavelink and we do a lot of PE and DVT work as well. Then the IO stuff is very well organized and run.

I feel like the trainees get a very good experience. It is a beatdown. It's a lot of call, it's a lot of work, but that's what I wanted as a fellow, and so that's what I tell people. It's time-consuming but worthwhile.

[Dr. Michael Barraza]
Look, you only have so much time to learn IR, and one thing that's unique about the specialty is that it’s always changing and it's every part of the body, so everybody knows you go into your first job and you're doing stuff you've never done before. The people that I talk to, everyone that I'm advising, I tell them you want a beat down, you want to be busy. It sounds like it's a pretty diverse training program in terms of what you guys see.

[Dr. Rehan Quadri]
Yes, and I try along those lines always to give the trainees the core fundamental skills in every case. It's access, wire catheter skills, ultrasound skills, fluoro skills, CT skills. We have hybrid suites with CT and fluoroscopy, but at the same time, we try and give them exposure to stuff if they end up working in a place where they don't have the technology that a big academic center has as well. So they get the tools to accommodate any situation whether or not they've seen this minute pathology that's very nuanced or not. They'll be able to handle it when they get to it.

[Dr. Michael Barraza]
It sounds like there's some flexibility too. I have to give a shout-out to my guy Devin Moody from your program who's joining my practice and we do a lot of neuro work. He's been able to arrange some elective time looking at some neurointerventions and stuff like that to get him ready to start out on the right foot. All in all, it sounds like a really comprehensive, great training program and Dallas is a good place to live, man.

[Dr. Rehan Quadri]
Yes, it's awesome. I got into IR because my neighbor was a neurointerventionalist. This was back in Maryland. I went to football camp and one of the guys I played with, I was like, "I don't have a summer job," and he goes, "Oh, well, my neighbor's a neurointerventional radiologist." I was like, "Really?" He was like, "You want to just come with me?" I went and I was like, "This is the coolest thing I've ever seen." I was like, "I think I'm going to do this." After that, I was sold. I was like, "I'm going to do this."

Then when I was at UT, the nice part is you can rotate on neuro IR, you can rotate on ADI, you can rotate on vascular. Actually, we do a rotation with vascular surgery so they get to do a lot of FEVARs, and so they get the gambit of experience.

[Dr. Michael Barraza]
Nice. Right on. We got a lot of trainees out there, listen, apply, and it's about that time, right?

[Dr. Rehan Quadri]
For sure.

(1) Defining Clot in Transit

[Dr. Michael Barraza]
Let's talk about clot in transit. I know you guys are doing a lot of thrombectomy-type work for DVT, PE. Let me just start by saying, what the hell is clot in transit, Rehan?

[laughter]

[Dr. Rehan Quadri]
The definition is rather vague. Traditionally, what you think about in the worst-case scenario is the washing machine clot. There's a piece of clot that's in the RA or in the RV and it's just bouncing around and the next step is to go to the PA. Depending upon what the size it is and depending upon if they already have clot in the lungs or not, the mortality can be up to 30% to 40%.

[Dr. Michael Barraza]
Wow.

[Dr. Rehan Quadri]
Most papers will quote it at 29%, some will quote it at higher than that. It's something that generally has been thought of as an emergent problem. Then there's also the notion of clot in transit being something that's partially adherent, whether it's to the wall of the vein, whether it's to the valve, to the atrial wall, or to the most common thing we see as a catheter or device pacer leads, different kinds of things like that - particularly dialysis catheters. Some people call it clot in transit or they'll use the term free-floating thrombus.

[Dr. Michael Barraza]
Yes, I've heard that more frequently and clot in transit, I'm starting to hear more about it now.

[Dr. Rehan Quadri]
Yes. Traditionally, they say it's supposed to be in the RA or in the heart, but it can actually be in the cava, but it's very rare that you would catch it in the cava because at that point, it'd probably end up in the cardiac chambers.

(2) Detection and Diagnosis of Clot in Transit

[Dr. Michael Barraza]
Okay. How is it traditionally diagnosed?

[Dr. Rehan Quadri]
I would say the most common is ECHO and not infrequently it's a finding on an ECHO when you're trying to categorize a PE and when they get the transthoracic ECHO, they'll notice in the RA that there is a, they'll call it an echogenic mobile density. The other time you see it is incidentally on CTAs, and then I haven't really seen it diagnosed. I'm sure this happens, but at the time of a pulmonary embolectomy/thrombectomy, I'm sure they see it on that as well.

[Dr. Michael Barraza]
Sure. I was going to ask you when you look for it, but in most circumstances when you're dealing with a heavy clot burden with pulmonary emboli, you're going to be getting an ECHO anyway, right? Or do you ever specifically go about looking for clot in transit?

[Dr. Rehan Quadri]
For most of our PE cases - so we've done about 13 clot-in-transit cases total. Because we see it a lot in the Parkland population and also in the Clements population, it is something that the cardiologists look for more when we get ECHOs in the setting of PE, but a common reason that we've had in our case series is actually catheter malfunction. Then we'll get an X-ray, and then they'll do a venogram potentially or they've exchanged the catheter a couple of times, not sure what's going on. Somebody will get a CTV or CTA because in a combination with the catheter malfunction, they have SVC syndrome-like similar symptoms, swelling.

Then you end up seeing it on the CTA, which is hard because you really have to get a good venous phase, and that timing is difficult. So, then you end up getting an ECHO to really confirm it.

(3) Integrating Clot in Transit into Existing Clinical Thromboembolism Algorithms

[Dr. Michael Barraza]
How does this factor into your treatment algorithm for treating PEs or other venous thromboembolism conditions where you're going to be thinking about doing a thrombectomy? Are you ever going in and just treating the clot in transit or is it typically in conjunction with the treatment of a PE?

[Dr. Rehan Quadri]
It's both. The first case we did, the patient actually had a dialysis catheter and they had about what measured 2.8 centimeters on the transthoracic ECHO. It was basically like a lollipop clot coming off and it was connected to a fibrin sheath, but that wasn't apparent on the ECHO. They just saw the clot bouncing around in the RA. They called it a clot in transit and they did have PE. The PEs were relatively small and peripheral, but their problem was recurrent PE, malfunction of the catheter, and at instances, the catheter getting infected frequently.

In that setting, we went in, took out the clot in transit, but the PE being relatively small and peripheral, we didn't actually go for it. Actually, the PE resolved with heparinization.

[Dr. Michael Barraza]
Yes, it makes sense. You don't want a 2.8-centimeter clot going through in the pulmonary arteries. That's going to be, in normal size PA, it's going to be occlusive.

[Dr. Rehan Quadri]
Yes, basically. Across the spectrum, the one thing I've learned is people rip out catheters all the time and fibrin sheets are probably left there. Does it matter in most cases? People say no, but honestly, we don't really know in a lot of instances. You don't necessarily see that person come back to your institution for the problem or different things. We're just trying to figure that process out. We send a lot of the clots for path[ology] as well.

[Dr. Michael Barraza]
Do you?

[Dr. Rehan Quadri]
Yes, so almost all of them are mixed.

[Dr. Michael Barraza]
For clot in transit or the PE as well?

[Dr. Rehan Quadri]
The PE is usually acute, and then the clot transit is usually mixed.

[Dr. Michael Barraza]
That's very interesting.

[Dr. Rehan Quadri]
It'll harbor there for a while. The mixed part sometimes is that the entirety of the clot is chronic, and then there's a small piece that's acute. Or it's like the distribution is hard to get when we send the path, but they generally will say, yes, there's more than just acute stuff. They'll say there's fibrin basically, there's organization to it.

(4) Treating Clot in Transit: Lessons Learned in Dr. Quadri’s First Case

[Dr. Michael Barraza]
That makes sense. Let's talk about for a minute how you treat them. What are you usually using for treating these?

[Dr. Rehan Quadri]
It's interesting, the first time I was asked to do this was - we have a cardiothoracic surgeon who actually does cardiac transplants, his name's Dr. Huffman. He is extremely well-versed in AngioVac. There was a consult that was sent to both of us for a malfunctioning dialysis catheter and a clot in transit. He was like, "This guy's a dialysis patient." He's like, "Putting this guy on VV-ECMO is going to be a nightmare." He's like, "I'm not going to be able to get the cannulas in." He's like, "We can do it, but realistically, this is a borderline clot. It's stuck to a fibrin sheath. It's not a true clot in transit, but it's concerning." I just had a conversation.

I said, "Look, in training, when I was at UVA, I worked with Dr. Kaja and Dr. Haskell and all the attendings there did a ton of advanced thrombectomy work." I'm really lucky that they were able to teach me these skills and how to navigate these problems. I said, "Now, there's a 24 French Inari catheter." Before that, it was only 20. I said, "Technically, we can get - it's eight millimeters, but in reality, these clots are relatively spongy. Even though it's 2.8 on the ECHO, there's probably some magnification there." We got a CTA and it was ranging from 1.5 to 2.8. Then having done a lot of iliocaval thrombectomies with Haskell and Kaja, I was like, "We've taken out significant pieces of clot in one fail swoop."

I was like, "I think I can get this," but I would just need either transesophageal ECHO or I would need an ICE catheter, so I chose to go ICE. Huffman was like, "Look, I'll back you up. Anything happens, you let me know."

[Dr. Michael Barraza Barraza]
That's awesome. It's so great going into a case like that.

[Dr. Rehan Quadri]
Yes, I know. He's awesome and he's this huge dude and he's just so reassuring. He's got this really, really comforting vibe to him. When we were looking at the case, he was like, "No, don't worry about it. You'll be fine." He's like, "It'll come out."

[Dr. Michael Barraza]
Dude, that's awesome.

[Dr. Rehan Quadri]
He was like, "You'll get it out there." Because he's taken out stuff through AngioVac that's like four centimeters.

[Dr. Michael Barraza]
It's so fun. Getting to do something you've never done before. Not a lot of people are out there doing that and that's what makes this job so fun. That's one of the best parts.

[Dr. Rehan Quadri]
Yes, and the fact that the guy was in a real bind, and then ended up doing very well after the situation was good. Then also having great colleagues at the time. Actually, Joseph McLaughlin was there. He was one of our former faculty. He went to Wisconsin and I said, "What do you think?" He goes, "I don't know, but I'm in."

[Dr. Michael Barraza]
[laughs] That's awesome.

[Dr. Rehan Quadri]
I was like, "All right, let's do this."

[Dr. Michael Barraza]
What'd you use?

[Dr. Rehan Quadri]
We went in with the 24 French Inari.

[Dr. Michael Barraza]
Did you use a FlowTriever?

[Dr. Rehan Quadri]
Yes, we used the FlowTriever. Then at that time, they had just come out with the FLEX. We didn't necessarily need the FLEX, but it was extremely helpful. In our heads, we're like potentially, it could accommodate more than what we thought and we could potentially angle if we need to by bending the wire, putting the wire in the PA, and getting the right trajectory. Then we decided to go with ICE. We have St. Jude, and then we also have AcuNav. I like the St. Jude catheter, but they're both, at the end of the day, the same functionality. The first thing we did was got a left groin access, had to partially recan[alize] the veins because they were pretty stenotic.

[Dr. Michael Barraza]
Why left instead of right?

[Dr. Rehan Quadri]
I put the ICE in the left groin.

[Dr. Michael Barraza]
Oh, okay, for the ICE.

[Dr. Rehan Quadri]
The first thing I do is I evaluate the clot and I establish a baseline because I want to make sure that I got the entirety of it and there's nothing left.

[Dr. Michael Barraza]
Totally.

[Dr. Rehan Quadri]
Since his issue was recurrent PE, recurrent infections, catheter malfunction, I was like, "We actually need to clear the majority of this." We took several cine clips. Also, it's good to just get your landmarks down before you bring your catheter in because the one fear that we did have was that, if we break off the clot as the catheter is advancing in, that's not ideal. Using the ICE, we were able to, because on one hand, you could put a wire through the catheter, get a through and through access, and then the catheter would be directly in line when you bring up the FlowTriever, and then you could do your pulls that way.

There's a chance that the wire could knock off the clot. After doing 13 of these, the likelihood of that is not as high as I thought it was. In the first one, we decided to get a wire up very carefully with ICE guidance. We went into the right subclavian, it was a right IJTDC. Then that gave us a nice directionality along the course, and then we put in a 24 French Gore DrySeal. We used a 65-centimeter. He was a pretty tall guy. Then we advanced the catheter up over Super Stiff and Amplatz. The first wire we put in was the glide wire and then exchanged. The big thing with the ICE is that, so I just follow the traditional home view, and then go from there. I go up with the ICE catheter pointed anteriorly.

A good landmark as you're entering. For starters, since it's not over the wire, I use a 45-centimeter 9 French sheath. Our ICE is the 8 French catheter, but I like to have a little bit of room around it. Then once it comes up, I make sure the catheter's pointed anteriorly as it enters the RA. You can either use the eustachian ridge as your marker, which is this echogenic line that shows up, and then you should see the tricuspid valve. Then you know you're in the RA, tricuspid valve, and RV. One way you can confirm that, if you want to, is before you come up from the cava, you can confirm which direction turning gets you aorta and which direction turning gets you liver, and then you can set clockwise to be that way. So then you know you're going interatrial septum or ventricular septum relative to free wall. Then from there, if you are worried that you're going to break off the clot or you can't see the clot even with the standard rotation of the catheter without adjusting the torque or the posterior-anterior angulation, you can actually oftentimes just decrease the depth.

It's that the depth is so large that you're not seeing what's in the near field very well. Then there is also a gain function on the ICE catheters. In IR, we use it for TIPS mainly.

Either the rep's there or the tech's there and you're just like, "Can you fix this?" and they're just messing with and messing with it. I spent a lot of time before we did this case just getting comfortable with the settings.

[Dr. Michael Barraza]
That's what I need to do.

[Dr. Rehan Quadri]
That's what I really advise people to do. The IFUs are great, the videos are great. The cardiology literature has a lot of stuff out there.

[Dr. Michael Barraza]
The first time I did a TIPS with ICE, I didn't have anybody with me who'd done it before. The guy that came in for the case, I was like, "This guy's going to make this so easy." All he was there for was to turn on the system. He was like, "Oh, I've never actually seen one of these." I was like, "Okay."

[Dr. Rehan Quadri]
Honestly, the biggest mistake people make is they break it as they're plugging it in and it doesn't connect properly and it wastes so much time in the case. Just look at the device, look at how it connects and locks before you put it in.

[Dr. Michael Barraza]
Totally.

[Dr. Rehan Quadri]
Then definitely put a sterile probe over it for this particular case just because you're going to be moving in and out quite a bit to adjust.

[Dr. Michael Barraza]
Are you doing angiography as well either in the cava or the heart or is this primarily using ICE guidance?

[Dr. Rehan Quadri]
Initially, we were afraid to pressurize because on the ECHO, their RVSP and their TAPSE was pretty high, unfortunately. We weren't sure if they could tolerate much of an injection. My colleague, Biona - she actually had done a case of clot in transit with the FlowTriever previously. She actually used TTE and had that same fear, and so it was nice to have her advice. Then, when we went up, we just thought it better to not inject yet and then see if we can get it all done with ultrasound. If we needed to, we would have. We did end up doing a gentle puff of saline under the ICE to see how the clot moved.

[Dr. Michael Barraza]
Cool.

[Dr. Rehan Quadri]
We were like, "Is it going to pop off or not?" You'd be surprised every time the anesthesia was like, "Oh, I'm going to give him some more meds," you'd see bubbles showing up. In our head, I was like, "I hope that's not too many." We confirmed that he didn't. That's another thing on the pre-op ECHO, you really need to confirm that they don't have a significant shunt, an interatrial shunt.

(5) Clot in Transit in Patients with Shunts

[Dr. Michael Barraza]
That's very important. I meant to ask you that, in either a shunt or just a flat-out like a PFO, are you looking for that before you start doing these?

[Dr. Rehan Quadri]
100%.

[Dr. Michael Barraza]
What do you do if there's a shunt?

[Dr. Rehan Quadri]
There was a PE that one of my colleagues had to do, and in fact, there was a clot already across the PFO-

[Dr. Michael Barraza]
No way.

[Dr. Rehan Quadri]
-plugging it and it was hanging on the other side.

[Dr. Michael Barraza]
That seems bad.

[Dr. Rehan Quadri]
They went up, got the PE out, and then it went to cardiothoracic surgery and they had to close it up. The problem with closing it beforehand if they have significant PE, so there's an interventional cardiologist and aN ICU attending that I work very close with on our PE response team and that team also, it's more like a VTE response team. We basically look at all high-risk DVT and all high-risk PE. We talked it through and there's not a lot of literature on it because I guess after the COVID era, the volume of PE has drastically increased. We see a lot of these shunts that open up and if you close it, they might go under right heart failure because that's partially decompressing the pressure.

We discussed with Luna, who's the structural heart specialist about closing them and he said, "I don't know if that's a great idea. We'd have to really look at it case by case." He has definitely helped me out when we were trying to do bubble studies in the procedure as well.

[Dr. Michael Barraza]
It's probably also hard to gauge what the hemodynamic outcome of that is going to be when a lot of these patients also have big PEs. That's got to be challenging. When you're actually doing the thrombectomy portion, when you're aspirating, how are you evaluating that you got the clot?

[Dr. Rehan Quadri]
We finally line up the ECHO probe exactly where we want it. Then the one thing I will say is you want to rotate the ECHO to where your position is, and then rotate it just a little more and then it'll slide right back into place and somebody just has to man that. Usually, the fellow is just holding that in place. Then from there, you make sure that your wire is in the trajectory of the clot with the ECHO. You see it in the same plane, you like the angulation, and then we'll also do fluoroscopic continuous guidance as it's coming up. I described this actually. It's funny, I actually said this to Devin once, I call it the “Shamu” sign.

You just see the Inari pop up all of a sudden.It's just this huge, hunking thing coming up and it's almost like Shamu launching over the rocks. It always makes me just say, "Goddamn it, hell yeah." Just when it's pointed right at it right off the bat, you save so much time. You feel great, you know your pull's going to be successful. The first case we had that Shamu sign, and then we hit it, we ripped it, and the entire thing launched out

[Dr. Michael Barraza]
Dude, that's awesome.

[Dr. Rehan Quadri]
The fibrin sheath along with the lollipop clot.

(6) Clot in Transit with Concurrent Pulmonary Embolisms

[Dr. Michael Barraza]
Oh, cool. After that, you're looking under ECHO and seeing everything's there and it's gone and you're cheering and everyone's proud of you and it's great. What if you have to do a PE too? What order are you doing it? Is it clot in transit first or PE?

[Dr. Rehan Quadri]
Exactly, the clot in transit first if the PE is not massive. If it's massive, then we go with the PE first. Very frequently, the clot in transit can be obtained with your wire position in the pulmonary arteries, to begin with. Access is key here. We're sticking everything we can for backup situations if necessary. Sometimes I'll even stick the left GSV and have a pigtail in the pulmonary artery as we're doing the case.

[Dr. Michael Barraza]
That makes sense, yes.

[Dr. Rehan Quadri]
I forgot to mention this, but we always check the PA pressures prior to starting. We'll check the PA pressure, we'll check an RV pressure, and either we'll use a Swan-Ganz balloon float technique or not over the wire form pigtail push up to the PA and do that traditionally in the beginning after we've done our ICE evaluation of the clot.
[Dr. Michael Barraza]
Do your equipment selection change if you think you're going to be doing both or if you're just going to be doing the clot in transit?

[Dr. Rehan Quadri]
I like the 24. I'm almost always putting in a 24 for a PE case. I feel like the 24 flex has the best trackability and through that, I'll just telescope 16 or I'll even put in a 20 curve. Even for the clot in transit cases, sometimes we put in a 20 curve giving up the wire, got it pointed right where we wanted it, and pulled off some pretty chronic stuff. Yes, I always start with the 24 flex. There is the new Protrieve sheath, which is interesting.

[Dr. Michael Barraza]
Interesting. I haven't seen that.

[Dr. Rehan Quadri]
Yes, it's nice, especially for filter retrieval. Dr. Kaja actually used to do something similar at UVA. He would partially deploy a wall stent when we were doing cava cases. I haven't found an instance of it where I would use it in an in-transit clot that was already at the level of the heart.

[Dr. Michael Barraza]
Right, because you may be going after stuff in the PAs anyway.

[Dr. Rehan Quadri]
Exactly, but if it was below the level - so there was one case where it was going from the hepatic veins into the RA and I thought maybe we could have gone in with the Protrieve sheath, encased the clot in that funnel, in case it broke off, and then also just been directly in line, and done a pull, and you can do a pull through the Protrieve sheath as well, which is nice. That's the only other addition, but usually, it's 24 French Gore DrySeal, bilateral groin access, at least, if not an IJ.

Then, we dissect out the catheter, just in case, and we're ready to go with potentially putting a wire through that if we need to. Then a 9 French sheath for the Acunav. Then if we do an IJ access, it's usually a 6 French sheath for a pigtail.

[Dr. Michael Barraza]
What happens next? You get the clot out of the heart, maybe PAs or not, where do you go from there?

[Dr. Rehan Quadri]
Everybody else in the room starts taking the most number of pictures I've ever seen in my life at that moment and it drives me crazy. They're just snapping photos talking, but that's the most stressful moment for me. The first thing I do is I measure the PA pressures and I make sure that they haven't changed. If I need to take an RV pressure, I'll take an RV pressure. That's when I will usually inject. After I've confirmed with the ICE that there's nothing hanging around that I'm going to break off. Even at that moment, sometimes you can inject through the catheter. If you feel really comfortable and you want to see if there's any sheath left because that sheath is stuck, it's not coming out.

If you pulled off what we call the lollipop at the end, the rest of it is going to be there. You can more comfortably potentially inject through there, but I do usually inject through the Inari from below and maybe even the Gore DrySeal. Then if I have a pigtail and the PA, I'll also do a PA-gram. Once that's all good, then it's all about hemostasis or exchanging the catheter, one of the two things.

(7) Dr. Quadri’s Most Challenging Clot in Transit Case: a Brief Case Study

[Dr. Michael Barraza]
One more question I've forgotten to ask. Have there been any particular cases that were especially challenging for one reason or the other? We talked about clot along the walls. I would imagine those are probably harder to get out in something that's just sitting along a TDC.

[Dr. Rehan Quadri]
Yes, so the hardest case we had was, she was an elderly female that had had a port for about three or four years and the port had a 1.8-centimeter clot at the end of it. It wasn't really mobile, it was almost stuck to the RA wall, and so two things came to mind. One, I was afraid of suctioning on the wall, and then collapsing the RA or potentially pulling out the volume of the RA. In a male, an adult male, your RA is 60 to 120, maybe even 160 in volume if it's super dilated on the ECHO.

If you do a 60cc pull, you're probably not going to dump all the volume realistically and the volume is not as big of a deal when I was talking to Huffman about it because with AngioVac, he's like, "We're just continuously pulling." They do have the circuit putting blood back in, but at times if it's not matched, he's like, "You're usually still fine." Then the bigger fear is that, are we going to collapse the RA walls and potentially send him into a complete loss of venous return and cardiac failure? When I spoke to Huffman, he was like the likelihood of that happening is extremely low.

We looked at the force and the suction of the catheter and even though it's extremely strong, collapsing the walls would be very, very difficult. Just with the sheer size and morphology of the RA. Not saying that it's not theoretically possible and not saying that I didn't freak out about it, we did. One way around it for this case is I intentionally used the 20 curve. We took the ICE from the contralateral IJ, down in, visualized the clot, and we saw where the length of the catheter was and where it terminated. Then I went up with a wire up the ipsilateral IJ, took the 24 up, took the 20 curve up, unsheathed it.

The hardest part about this case was timing the unsheathing of the catheter and keeping it steady once it was pointed at the clot. Because the RA is, in this female, even though she was elderly, relatively small female, you would think it's smaller, but her RA was actually pretty dilated. It was like trying to find a needle in a haystack. Finally, you have two fellows holding one sheath, another fellow holding another sheath, I'm angling it this way, and one person's holding the ICE. It's just like pull, pull, pull, and you're just like, of course, there are several pulls without the clot in it. This case, the key to me being able to even accept it was the fact that we had the flow saver FlowSaver.

I was able to give her all the blood back. Prior to that, when I did cases as a fellow and watched Dr. Kaja, he was so careful about the number of pulls, where he pulled, how much volume he took. There was always blood in the room. I always have two units in the room no matter what, anyways. I would say that case was so challenging just because every device that you have in there interacts with the other device. It can sometimes prevent or help your catheter be forced in a direction.

The key was just getting our wires angled correctly, getting our catheters angled correctly, and pushing whatever we needed to. Sometimes people even inflate a balloon alongside the Inari to push it in a direction. That's, I guess, why that case was pretty tough, but we got it in the end.

[Dr. Michael Barraza]
That's what counts. What else do you want to talk about that I didn't cover?

[Dr. Rehan Quadri]
I guess the thing that I've learned at the end of this is, and I'm obviously pretty new at this whole attending gig being only two or three years out, which is the thing I love about UT Southwestern. You have so much support. We have senior and junior people who have everyone's back. We all team together. It was like two or three attendings in every case, two or three fellows. The indications for this procedure can get very vague because a lot of catheters and devices and people will have what looks like a suspicious clot. The literature goes one way or the other, particularly on the free-floating clot. It used to be thought that it's going to break off and go somewhere.

Realistically, a true clot in transit, you're more likely to see in somebody with tricuspid stenosis. In reality, something stuck somewhere. Is it really worth it to put them through this and go through this procedure? Yes, it's a step down from AngioVac. That was the whole point of why we created this; to give an alternative, but what I found the best indications were recurrent PEs, recurrent infections, recurrent catheter malfunction, and somebody with a very bad cardiopulmonary status where they really couldn't afford to have that clot break off.

I guess that's the message that I want to convey. You really just have to look at the case and look at whether or not you can get away with just pulling the catheter and heparinizing them or do you really need to go through this entire process?

[Dr. Michael Barraza]
Right on, man. Look, this was awesome. Thank you for joining us and thanks for going through this with us. This is something new for me. Thanks to our listeners for tuning into another one of these and we'll catch you on the next one.

[Dr. Rehan Quadri]
Perfect. Thanks for having me, I really appreciate it.

Podcast Contributors

Dr. Rehan Quadri

Dr. Rehan Quadri is a practicing interventional radiologist and an Assistant Professor in the Vascular Interventional Radiology division of the UT Southwestern.

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). (2023, February 6). Ep. 289 – Treating Clot in Transit [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.