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BackTable / VI / Article
Arterial Thrombectomy in Acute Limb Ischemia: A Practical Guide
Melissa Malena • Oct 31, 2023 • 144 hits
Interventional radiologist Dr. Alexander Ushinksy shares his procedural technique for arterial thrombectomy in acute limb ischemia. Preoperatively, each patient must be individually evaluated to make a decision on antibiotic administration and sedation. Most patients are sedated with Fentatnyl and Versed, but general anesthesia must also be considered for longer surgeries. The surgical procedure itself requires a quality diagnostic angiogram and intentionality in wire and catheter choice. Dr. Alexander Ushinsky highlights the importance of considering factors like fibrinogen levels, heparin rate, and the availability of smart order sets when deciding on treatment approaches. Postoperatively, continuing a heparin drip can help provide direction in compression and closure decisions. This article features transcripts for the BackTable Podcast. We’ve provided the highlight reel here, and you can listen to the full podcast below.
The BackTable Brief
• Most acute limb ischemia procedures can be carried out under minimal to moderate sedation using Fentanyl and Versed. General anesthesia (GA) may be considered for longer procedures, for patients in severe pain or for patients with restless leg syndrome.
• Acquiring a high-quality diagnostic angiogram is paramount, often positioned in the distal external iliac or common femoral artery based on the thrombus location.
• For crossing the occlusion, the choice of wire and support catheter is crucial. Dr. Ushinsky often favors the 014 Glidewire Advantage from Terumo for its atraumatic and reliable nature.
• Timing, the extent of thrombus, patient suitability, and facility support can all influence clinical decision making when choosing between lysis and arterial thrombectomy.
• In lysis cases, it is essential to choose a lysis catheter with a length that spans the thrombus, ensuring outflow and inflow holes for effective delivery of the lytic agent.
• Retaining a patient on a heparin drip post-procedure can be beneficial, especially in cases where residual thrombus remains, transitioning to antiplatelet management or other alternatives based on clinical evaluations.
Table of Contents
(1) Patient Preparation for Arterial Thrombectomy
(2) Access, Imaging, Heparinization & Wire Placement
(3) Arterial Thrombectomy vs Lysis
(4) Arterial Closure & Post-Operative Care
Patient Preparation for Arterial Thrombectomy
Endovascular approaches to acute limb ischemia demand precise protocols, grounded both in empirical evidence and practitioner expertise. Dr. Ushinsky illuminates the intricacies of patient preparation, emphasizing that not all angiographic procedures necessitate prophylactic antibiotics—though caution is urged for patients with signs of gangrene or soft tissue infection. Sedation, typically achieved through Fentanyl and Versed, facilitates most procedures, but the extent of thrombus or unique patient pain levels might necessitate general anesthesia (GA).
[Dr. Chris Beck]
Going back to patient prep, do you want to talk about antibiotic regimens, sedation level, all the above?
[Dr. Alexander Ushinsky]
So in the realm of endovascular approaches, we are generally not offering just prophylactic antibiotics for all angiographic procedures. In our practice, we don't do that. I know some practices give Ancef pretty routinely. Certainly, if the patient has any evidence of gangrene or soft tissue infection, that needs to be covered definitely, and I would be very concerned if that weren't the case and I was expecting to leave some sort of implant like a stent or a stent graft. Routinely, I don't give Ancef or anything for skin floor coverage per my angiograms.
[Dr. Chris Beck]
Then how about sedation?
[Dr. Alexander Ushinsky]
I do almost all of these procedures under, we call it minimal sedation, but where I trained before, we called it moderate sedation. It's Fentanyl and Versed sedation with nurse and physician monitoring as is common in a lot of catheterization labs, IR labs. I would say that for most of the procedures I've done for acute limb ischemia, whether it's lysis catheter placement or placement of mechanical thrombectomy, the patients do very well with that type of sedation. Angiography is generally not a particularly painful procedure, and these thrombectomy systems are not much larger than what we routinely use for leg angiogram.
[Dr. Chris Beck]
Any patients that could benefit from GA or deeper sedation?
[Dr. Alexander Ushinsky]
Good question. If you're expecting a longer procedure, I would definitely consider GA, depending on the extent of the thrombus. If you're thinking this may be a three, four-hour procedure to remove all the thrombus and you're going to do a single-session procedure, you may consider GA. The other times where it can be helpful are patients who are in such severe pain from their acute limb ischemia that they just won't tolerate laying on the table even or any sheet touching their foot and things like this. You may benefit from it.
Then the other time where it's helpful is we get a fair amount of patients who have restless leg type syndrome or just difficulty keeping their feet steady. Sometimes this almost falls in the realm of claudication and rest pain, from maybe some underlying chronic limb ischemia or acute and chronic limb ischemia. For those patients, just to be able to have them be still to do the procedure, consider GA. The vast majority do pretty well with physician-directed monitored sedation.
[Dr. Chris Beck]
Just routine Fentanyl Versed, right?
[Dr. Alexander Ushinsky]
Yes, exactly. We use Fentanyl Versed. I know some places will use Precedex and things like this, but we don't routinely do that in our practice.
[Dr. Chris Beck]
Set the stage for us because you can have any patient. This can be the ideal patient, can be a nightmare patient, or whatever, but let's lay the table stakes as far as what kind of patient that you're going to be dealing with and then we can dig into the details.
[Dr. Alexander Ushinsky]
Which one would you like me to start? I do them all the same.
[Dr. Chris Beck]
Oh, really, okay. All right.
[Dr. Alexander Ushinsky]
Every procedure starts the same.
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Access, Imaging, Heparinization & Wire Placement
Dr. Ushinsky emphasizes the significance of thorough preparatory diagnostic angiograms for patients with acute limb ischemia, typically starting with contralateral groin access. The acquisition of these angiograms often involves segmented, station-based shots due to varying technologist expertise. Dr. Ushinsky also advocates for a tailored approach to heparinization based on individual patients, with heparin typically introduced after a quality diagnostic angiogram is obtained. Heparin administration can involve an initial bolus, followed by ACT checks. The commencement of the actual intervention involves achieving wire access past the occlusion, which tends to be more straightforward with acute limb ischemia compared to chronic cases. The tactile feedback from the wire provides insights into the nature of the occlusion. After confirming correct wire placement using an angiogram, Dr. Ushinsky highlights the importance of identifying the occlusion's exact location and deciding on an immediate intervention or a staged approach.
[Dr. Alexander Ushinsky]
Usually, I'll have some cross-sectional imaging. The patient has a CTA, and I know what I'm getting into from the CTA, to some extent at least. All my patients who have acute limb ischemia, I will start with contralateral groin access. They're in the IR lab, we've sedated them, ultrasound-guided contralateral groin access. I begin every case by going up and over. If needed I'll do an aortogram if there's some iliac disease that I'm concerned about from the CTA, but in general, all patients begin with a diagnostic angiogram.
A nice diagnostic angiogram with the power injector with the flush catheter parked in a patent segment, usually in the distal external iliac or the common fem, depending on the site of the acute thrombus.
[Dr. Chris Beck]
You're going up and over and you're doing the diagnostic catheter and the affected limb, right?
[Dr. Alexander Ushinsky]
Yes, and I do a full runoff to the toes every time.
[Dr. Chris Beck]
Do you do it like one injection and the table will step along, or is it segmented, like pictures, reset, pictures, reset?
[Dr. Alexander Ushinsky]
I do stations to the foot. Our equipment can do step-and-shoot, the fancy stuff, but I don't know how to do it. I'll tell you, we have 9 or 10 labs that we cover at the university hospital, which means we have 40 or 50 technologists. Even in the perfect setting at 8:00 in the morning on a Monday, to find the tech who knows how to do that is difficult.
[Dr. Chris Beck]
The technology's there, but in practicality, I'm with you. I go through a lot of different labs, work with a lot of different technologists of varying skills and knowledge. I'm with you. All right. Shooting in stages, I got it.
[Dr. Alexander Ushinsky]
I'll say, it's important given that you may have technologists with different comfort levels to really be prescriptive in how you want the room set up, what kind of contrast you want, the injector. I generally use 50-50 contrast in the extremities. We usually use Visipaque as our contrast agent when we're doing extremities. I usually run through the plan with the technologist ahead of time as well to make sure that we end up with a good exam and a smooth flow to the case.
[Dr. Chris Beck]
Can you talk about, for some people that may have missed it, why you pick Visipaque for these cases?
[Dr. Alexander Ushinsky]
There's some thought that Visipaque is a little bit less painful for small vessel and extremity angiography. I'll say I've used some of the other contrast agents in the extremity from time to time, and the patients don't seem to complain about pain. I will say with CO2 injection, patients do get some discomfort sometimes in the extremity angiograms, but in general, that's why we use Visipaque. I saw a smaller contrast.
[Dr. Chris Beck]
All right. You're taking pictures, you've got good diagnostic high-quality pictures.
[Dr. Alexander Ushinsky]
Once we have a good diagnostic angiogram, identify the area of occlusion, the next thing I'll do is, the patient isn't already pretty aggressively heparinized, I'll heparinize the patient pretty aggressively for intervention. Usually, these patients come to us on a heparin drip. For the access, sometimes if I'm feeling cautious, I'll have them hold the heparin drip for a few minutes and then get access into the groin.
Sometimes just get access with the heparin drip running, knowing that I'm gonna be pretty aggressively heparinizing the patient in a few minutes anyway. I give my heparinization as just an initial bolus, and then get an ACT every 30 minutes or one hour. The bolus, I don't do in general, like a weight-based bolus dosing. I know some people do. We usually, depending on the size of the patient, start with about 7 or 10,000 units of heparin to begin with, and then check an ACT in about 30, 40 minutes and see how the patient's doing, and then assess from there.
[Dr. Chris Beck]
You ballpark it based on weight, and then check in ACT and then see where you're at in 30 minutes.
[Dr. Alexander Ushinsky]
Especially because in my practice, I deal with a lot of tibial disease in general, not as much in the acute limb ischemia space, but when I'm treating chronic limb ischemia, I generally need my patients pretty aggressively heparinized for a successful and safe procedure. I'm pretty comfortable being pretty aggressive with my heparinization for these patients as well.
Once I've heparinized the patient, I will exchange my 11-centimeter Sheath, for a long Sheath, then I'll park in a patent segment of the affected extremity. Usually, I start with a 6-French system when I'm doing these interventions.
[Dr. Chris Beck]
What do you like for your Sheath of choice? Anything that gets you up and over.
[Dr. Alexander Ushinsky]
We use destination mostly, through remote destination Sheath, nice braided Sheath. They're pretty hydrophilic. I will say the valve doesn't always stay on as well as some of the Cook Sheaths. One of my partners has a sub-special-ordered Cook Sheaths that he keeps for himself, but in general, we use the destination Sheath. With the Sheath up and over, I'll begin the true intervention here. As most of the things we do, the first step is getting wire access beyond the occlusion.
As opposed to the chronic limb ischemia patients, as you and some of the audience knows, with acute limb ischemia, it's usually pretty easy to cross the acute occlusion, the acute thrombus. It's soft, it's just like an acute DVT and the folks who are doing mostly venous disease. It's usually easy to have your wire across as opposed to chronic limb ischemia and park your wire across the occlusion.
That's also an important inflection point because there have been a couple times where I'm expecting acute limb ischemia and I have a lot of trouble getting my wire across the area of occlusion. Then you look back at the angiogram, you say, "Well actually, there's a lot of big collaterals here, and the patient's history sounded a little fishy, and I don't know that this really needs a lytic catheter. Maybe we need to just see what happens with some of our methods for chronic limb ischemia."
[Dr. Chris Beck]
It's like the wire test, right? Like the wire tells you a lot tactilely.
[Dr. Alexander Ushinsky]
Yes, exactly. Depending on where the site of occlusion is, I'll either use 035 guidewire for fem-pop, and then if there's some disease distal to the fem-pop segment, I'll usually use an 018 or 014 system for the entire procedure.
[Dr. Chris Beck]
You start crossing with an 018 or an 014 wire.
[Dr. Alexander Ushinsky]
Not infrequently, especially if I'm planning an intervention that will require that type of guidewire.
[Dr. Chris Beck]
What do you like for wires?
[Dr. Alexander Ushinsky]
We keep a reasonable stock. My favorite honestly is the Glidewire Advantage from Terumo. The 014 Glidewire Advantage more so than any of the other Glidewire Advantages. It forms an excellent knuckle at the tip, feels really atraumatic, and glides through, stays true lumen, I hope, and stays in the big capacious vessel once it forms that knuckle without going into the side branches, which just makes it really easy. I follow that with a support catheter.
I used to use the quick cross line from Spectranetics, but in the last six months or so, we've actually switched to a CSI product called the Vipercross. They have made from 014, 018, 035. It's a very, very hydrophilic support catheter. Really nice crossover. I use it, of course, mostly for my chronic limb ischemia patients where it's difficult to cross with the catheter, but since it's on the shelf and it's similar in cost to the quick cross and these simple extruded tube type catheters, I just grab that and use that.
[Dr. Chris Beck]
Great. All right. Wire goes easy, cross is easy, what next?
[Dr. Alexander Ushinsky]
Cross is easy, follow with the catheter, of course. The next step that I always teach my fellows is to do an angiogram and prove that you've crossed. You need to make sure that you're truly across the occlusion and just confirm that you're in patent Lumen. That's critical, I think, for a successful acute limb ischemia, endovascular case, and especially for lysis catheter replacement as well.
[Dr. Chris Beck]
Ideally, if you have something that's popliteal and then infra pop disease, where do you want to end up? How distal are you or you just park in a segment that's capacious?
[Dr. Alexander Ushinsky]
The first thing is that as soon as I think I'm through with the occlusion, I'll just prove that I made the vessel. That probably comes from my habits with crossing chronic occlusions. If the patient has concomitant chronic infra pop disease, I will usually, at that juncture, have a plan of whether I'm going to immediately address the infra pop disease and try to do a single session thrombectomy and treatment of chronic limb ischemia, or whether this is going to be a lysis catheter case where I'm going to address the infra pop and chronic disease at a second-day procedure.
[Dr. Chris Beck]
Alright, so you're all set up. You got your catheter, you're in a good spot distally. Are you going to talk about the next step or talk about the inflection points of what drives you to one treatment modality versus another?
Arterial Thrombectomy vs Lysis
Dr. Ushinsky highlights the transformation in acute limb ischemia procedures over the past several years. Not long ago, catheter lysis was the prevailing method, with the lysis catheter carefully placed to ensure optimal thrombus coverage. However, advancements in thrombectomy devices have now shifted the practice, offering quicker single-session solutions. Ushinsky underscores the critical decision-making involved in choosing between lysis and thrombectomy, factoring in variables like the extent of thrombosis, patient suitability for systemic TPA, and logistical concerns such as available hospital resources. Particularly notable is the ability of modern thrombectomy devices to offer treatment options to patients for whom lysis poses high risks, such as the elderly or those who've recently undergone surgeries.
[Dr. Alexander Ushinsky]
Sure. Why don't I start with what I would have done four years ago and talk about catheter lysis before we had a lot of this single session thrombectomy tool? It's interesting because I felt like I did a lot of lysis in my training, whether it's venous or arterial. My current fellows don't do very much at all because in both spaces, venous and arterial, we have so many excellent thrombectomy devices. They're less comfortable with lysis than I think maybe you and I were at our training.
The important things I think about once I've crossed if I'm planning to do a lysis case, is making sure that my lysis catheter spans the entirety that I have. Basically, outflow for the lytic, inflow and outflow. I choose a lysis catheter that has a length that will span the thrombus and try to make sure that I have one or two side holes beyond the thrombus and the patient outflow and holes throughout the thrombus.
Hopefully, one or two holes proximal to the thrombus to make sure that that TPA really can get out and marinate throughout that thrombus. That was my pattern four years ago, five years ago. I would stitch in the Sheath and ship the patient to the ICU for an overnight lysis. Nowadays, as you suggest, now there's an inflection point. The way that I think about whether to do lysis, there's a couple of factors that come into my mind, whether to do lysis or whether to do a single session thrombectomy.
One question is just the timeframe. Is it very late at night? Do we have the time? Do we have the technologists in the facility support to do a multi-hour procedure? On-call at two in the morning with traumas coming in may not be the appropriate use of resources necessarily to do a two-hour thrombectomy procedure and back up the trauma service. It may not be a safe bet.
The other thoughts that I have are the extent of the thrombus. It's pretty difficult to thrombectimize very small vessels sometimes, and especially if there's quite a lot. If all three tubules, and there's a fem pop is just a very large thrombotic burden. I tend to err towards lysis unless I'm really prepared for an extensive slog. Those are some of my considerations there.
Then for the patient that has a pretty small amount of thrombus, I feel really strongly about some of the single-session thrombectomy devices in lieu of lysis. It's even maybe in the middle of the night, if there's really just a small amount of disease and we can solve the issue, then I will err much more towards thrombectomy devices.
[Dr. Chris Beck]
Thrombectomy, single session treatment, then you wrap it up, and it's done?
[Dr. Alexander Ushinsky]
Exactly. Then the other consideration are patients for whom lysis is high risk. Elderly patients, patients with recent abdominal or other surgery, patients who just are not good candidates to have systemic TPA. We may not have had much to offer them years ago, but now I think the single session thrombectomy approaches are reasonable for lysis patients who can be heparinized but can't receive TPA.
Arterial Closure & Post-Operative Care
In post interventional closure, heparin reversal is a pivotal determinant, dictating the use of either manual compression or closure devices. The Activated Clotting Time (ACT) serves as a guide, with an optimal level below 200 for manual compression, while higher thresholds up to 250 can be accommodated when leveraging closure devices. Post-procedural management holds its own set of nuances. For instance, retaining patients on a heparin drip post-procedure, especially if residual thrombus exists, is a strategic choice. This can then be transitioned to antiplatelet management or, as conditions dictate, alternative treatments based on the patient’s clinical presentation. The subsequent care level, from ICU to standard ward, is shaped by the procedure's complexity and the patient's overarching health status.
[Dr. Chris Beck]
Can we dig in a little bit to post-care? Unless you want to talk about closure?
[Dr. Alexander Ushinsky]
All I'll say about closure is, it's a question of heparin reversal at that point, what level people are comfortable closing, and whether they use a closure device or manual compression. In my practice, in a patient who I'm planning manual compression, I would like to get their ACT to the level of 200 or lower. If I'm going to use a closure device, I'm comfortable stretching the ACT a little higher to 50 occasionally if we need to.
That's an important consideration in these patients. I'll often leave them on a heparin drip for a little bit of time, especially if we do have a little bit of residual thrombus like you and I were discussing. Those are all some considerations when you do think about closure.
I don't think any particular closure device is better than any others. There are a couple that are well-suited for patients with chronic disease in the CFA or the iliacs that you can visualize or some of the suture media devices. A lot of that is operator preference and what's just available in your lab. That's all I can say about that.
In post-procedure management, like I said, especially if there's some residual thrombus after these single-session patients, I might keep them for the evening. Let's say, it was a morning or afternoon case, I might keep them for the evening on a heparin drip. Then if we have good pulses and we feel like we've cleaned the thrombus and they don't have an underlying reason to need to be on a heparin drip, transition them back to antiplatelet management the following day. That's the perfect case, the patient, we know why they had it.
Some of those patients, especially that setting of an outpatient who may be re-thrombus, their stent has some mild symptoms, you can clean that up and maybe even send them home later that day after some protracted monitoring, especially if they're a reliable patient. We've had some success with that. I have a few of these patients who had endovascular treatment, haven't really quit smoking, are prone to thrombosing their stents, and we've successfully treated some of the reliable ones with the same-day outpatient approach this way.
For the ones that are a little less reliable that are a little more ill that are going to be hospitalized, usually, like I said, we'll consider a transition away from heparin either to oral anticoagulant or do an antiplatelet therapy the following day as long as their pulse exam and their clinical exam in terms of their motor and sensory is doing well the next day.
That's for the slightly more acute patients.
[Dr. Chris Beck]
Afterwards, are they going to the ICU setting or whatever floor that they came from originally? Just talk a little bit to where's the appropriate spot to send them post-care.
[Dr. Alexander Ushinsky]
Definitely. Just to call back for our lysed patients, in our hospital, they're almost always in the ICU setting when they're being lysed. We do have one step-down unit that can take them, so they'll occasionally be on the step-down. They need that high level of care to have frequent neurovascular monitoring.
For the folks who have a successful single-session thrombectomy, I don't think that they need ICU level of care most of the time unless there's any concern for compartment syndrome or something similar. Then those patients, especially after a successful treatment, are pretty safe to go back to floor level of care after the requisite post-angiography, pulse, and groin monitoring that we have and that most places do.
[Dr. Chris Beck]
Do you guys have a floor that is comfortable with the IRR procedures, or basically a unit where a lot of post-angiogram patients go, or just anywhere in the hospital is pretty good?
[Dr. Alexander Ushinsky]
In general, most of our patients go anywhere in the hospital. We have a tapered groin and neurovascular exam, post-procedure orders that are generally being done.
We do have a couple of units that are specifically higher acuity for vascular patients, one that's mostly managed by our vascular surgery division, and then a couple of the surgical ICUs and step-down units.
We don't routinely have the patients go to those either the acute limb ischemia patients or any other angiography, the PEs, and things like this. The PEs will go to the ICU for monitoring afterwards. In general, most of our units will take post-angiography patients.
Podcast Contributors
Dr. Alexander Ushinsky
Dr. Alexander "Sasha" Ushinksy is an interventional radiologist and assistant professor with Washington University in St. Louis.
Dr. Christopher Beck
Dr. Chris Beck is a practicing interventional radiologist with Regional Radiology Group in New Orleans.
Cite This Podcast
BackTable, LLC (Producer). (2023, April 24). Ep. 315 – Arterial Thrombectomy [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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