Radial vs. Femoral Access in IO Procedures
with Dr. Jason Iannuccilli and Dr. Chris Beck
Dr. Chris Beck and Dr. Jason Iannuccilli discuss radial vs femoral access in IO procedures, including the pros and cons of both, and a very informative "how I do it" for radial access by Dr. Iannuccilli.
Cite this podcast: BackTable, LLC (Producer). (2018, April 4). Ep 26 – Radial vs. Femoral Access in IO Procedures [Audio podcast]. Retrieved from
Full Transcript Below
In this Episode
Dr. Jason Iannuccilli is a practicing interventional radiologist with Rhode Island Medical Imaging.
Dr. Chris Beck is a practicing interventional radiologist with Regional Radiology Group in New Orleans.
Dr. Michael Barraza is a practicing interventional radiologist with Radiology Alliance in Nashville.
Podcast sponsored by Surefire Medical.
Disclaimer: The Materials available on the BackTable Podcast 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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Radial vs. Femoral Access in IO Procedures
Hello and welcome to the BackTable Podcast. BackTable is your resource to connect with your IR colleagues and learn tips, techniques, and the ins and outs of the devices in your cabinets. You can find all our previous episodes of the BackTable podcast and more on our free iTunes app. This is Mike Barraza returning as your host.
Today's podcast is brought to you by Surefire Medical. Surefire has the only expandable tip catheter to help physicians maintain blood flow while reducing reflux during chemoembolization and radioembolization. The Surefire Infusion System helps interventional radiologists deliver therapy deeper into tumors while protecting healthy tissues. Learn more at surefiremedical.com.
I'm joined today by Chris Beck and Jason Iannuccilli to debate femoral versus radial access for oncologic embolization procedures. Obviously this isn't a novel topic but it's a contentious one with strong arguments to be made for each. And really the only people who I think are wrong are the ones who still describe radio access as a gimmick or a fad, or my personal favorite that I've heard is calling it a parlor trick. So whichever is better, femoral or radio, is a matter of opinion and circumstance, but radial is here to stay and that's a fact and there's a growing pool of data to support its use.
So before we really get into that debate let's start with some introductions. Jason, could you tell us who you are, where you are, what you're currently doing in terms of trans-arterial cancer therapy.
Sure, absolutely. So I, just to backtrack here, in terms of training, I completed my radiology residency at Brown Medical School. Did an IR fellowship at UCLA Ronald Reagan Medical Center, graduated that in 2011 and then joined up with Rhode Island Medical Imaging as an affiliate associate with Brown Medical School in Providence, Rhode Island. I've been with that group for about seven years. I'm currently the division chief of interventional radiology since 2014. And we just recently established an interventional oncology division back in 2016, so I've been at that for almost two years now as the director.
My group, Rhode Island Medical Imaging, is a hybrid practice. It's a private practice that has an academic affiliation. We do have about 70 physician partners, 9 IRs, 3 NIRs. Very busy group, we cover five hospitals. The hospital I practice at, Rhode Island Hospital, is the largest. It's a level one trauma center, a major stroke center. For a non-transplant hospital we actually see a fair amount of interventional oncology practice. We perform about a 180 ablations per year and about a 150 IO treatments. We do do mostly drug-eluding beads for TACE, but some conventional TACE. We do Y-90, both SIR-Spheres and TheraSpheres as well as various combination therapies. We do do some bland embolization and some intra-arterial ethanol, mainly for renal cell carcinomas that would have a contraindication to ablation.
Okay. Chris, now your turn. You're no stranger to the podcast but for the sake of the newer listeners tell us your story please and what your trans-arterial cancer practice looks like.
Sure, thanks Michael. So my name is Chris Beck, interventional radiologist. I'm in a strictly private practice group primarily based in southern Louisiana. I primarily work at a hospital called Touro Infirmary in New Orleans.
Our interventional oncology practice is ... We're not a transplant hospital so it's mainly metastatic, colorectal, or neuroendocrine, for which our treatments range from anywhere between DEB TACE, conventional TACE, and Y-90. We're exclusively doing TheraSpheres for no other reason than one of my partners came from UF and we just selected glass because we thought it would simplify the process for our technologist.
Yeah, that's mine as well, interestingly. For a similar matter of convenience we are using exclusively SIR-Spheres where I am, and I'm kind of hoping to expand to more glass to mix it up. But we're not a transplant center either, we are predominantly Y-90. It's actually pretty uncommon to do chemoembolization here.
Chris, what's your preferred access site for these procedures and why?
For me, I almost always go femoral access. And I guess, when I was kind of making some notes on this podcast, I have all kinds of small reasons why I go femoral but, as I was making some notes on this, the real reason that I go femoral is just I have a high level of comfort with femoral access, I have a good feel for when the access is going right, when there's something wrong, and all the working catheters that I use or have access to - not that we couldn't get other ones - they're kind of like ... There's so many reverse curve catheters that come in, a kind of just common practice for us to use. And so it ends up being femoral access. And I think that if I had to really get down to the base of it it's probably just because I feel comfortable with that overall.
But some of the smaller reasons that I use femoral access, we have a couple of different cath labs that we work in, both at my main hospital and satellite hospital, and they're set up for ... It's just that the rooms are built for femoral access, and so if I ever do a radial access case, and we can kind of get into the nuts and bolts and Jason may have some good tips to help facilitate it, but it seems like the ergonomics are very geared towards doing femoral access. I can lay everything across the patient, the monitors are directly in front of me, the back table is behind me, and it's just from a standpoint, everything like my hands and my line of sight, everything is directly in front of me at a 90 degree angle.
I wouldn't say we do a lot of, but for the intraarterial cases that we do, Y-90 specifically, a lot of the catheters that we try and use are shorter working length catheters like if we're going to do a mapping. I was always taught to try and decrease the length of your catheters as much as possible. So if you can get a 65 centimeter SOS and then a shorter length Renegade that's 105 or 110, you get better injections for your mappings. And I have to admit, I'm a nut about my mapping procedures and I think that using some shorter working length catheters helps you get better injections and better pictures.
You have some special situations where if ... I can think of a case where it included celiac and it was considering whether we're going to have to go via the SMA and pancreaticoduodenal arcade to get to this tumor versus what I ended up doing, was just pulling a Mickelsen catheter into the celiac, which was completely and chronically occluded. And basically what I do is I just take the Mickelsen, park it in the occlusion of the celiac, and then I just kind of chip away with the microcatheter system. And then, ultimately, you kind of treat it like a CTO case, you kind of bust through and then all of a sudden you have access into your hepatic arteries. I'm sure that you could do this if you were doing a radial access case but I have just such a higher level of comfort with the catheters and coming from a femoral approach.
I understand. Is the Mickelsen your go-to for femoral access when you're doing celiac or SMA selection?
No, I almost always use a SOS. The only reason I used a Mickelsen for that case was just because a little more stability and it just seems to anchor in. Actually I think I tried with a SOS to get it in originally and it kept popping out every time I tried to probe with the microcatheter and microwire so I just used a Mickelsen for some added stability.
So I've made the switch to radial for fibroid embolization, but the only thing that's really keeping me from doing it in cancer therapy is just the barrier is really just having to train inexperienced nurses and techs who are just really very comfortable with managing femoral access patients. The place where I do the majority of my interventional oncology is just a really busy site and I can't waste half an hour having to set up an arm board and get everything set up a way that they're not used to.
I really don't even have that excuse because the cath lab that I work in, it's a cath lab mixed with cardiology and so the techs and nursing staff, everyone is very comfortable with a radial setup. And so for me, if I were to tell the techs, "Hey, let's set up for radial," they don't blink an eye, they'll set up for radial no sweat and they'll have the groins prepped in case of potential crossover. And we use radial access, it's just not my go-to access, especially when it comes to interventional oncology.
It's fair. And Jason, are you primarily a radial guy for IO?
I use radial whenever possible. It's sort of become my favorite access for a number of reasons which I'm sure we're going to get into here. But I just wanted to respond to a couple of things that Chris had said.
I would agree actually with both of you that comfort is key with these procedures. I mean any IR is going to tell you that the outcome of the procedure is directly related to how comfortable you are with the technique that goes into overall radiation dose exposure, contrast volume, patient satisfaction as well, I mean side effects from sedation. We load patients up with meds, when they're on the table for a long time they're more likely to get nauseous afterwards and have all sorts of side effects. So I agree comfort is key and I'm not going to tell you guys that this was a flip-the-switch kind of a thing when we went from femoral access to radial. I mean there definitely are some physical limitations.
First off, our rooms also were not designed with any sort of foresight into the fact that we're going to be using radial access at some point during their lifetime. We have some smaller rooms. We do have one room in particular that's a little larger that we prefer to use the radial access in whenever possible. The downside is that that room is not equipped with our 3D software, and that comes in real handy with these oncology cases, and if we're strictly using the room that's larger for the trans-radial we obviously don't have the benefit of using that technology. The room layout is tough but we have worked out ways to sort of overcome those limitations. And we can talk a little bit more about that as the conversation progresses.
But the other point that I wanted to make was one that ... I think it's interesting, my preference is for doing mappings and doing initial angiographic runs for TACE, for example. I find that my best contrast injections are obtained when I can actually park a catheter in the proper hepatic artery. So I usually try to use even a C2 although I don't like it as much because the tip kind of digs a little. And I'll advance that over a glide and sort of get it down deeper so that my contrast injection is primarily directed at the liver and I'm not getting contrast aversion to the spleen. So for that reason I found that it's almost easier and less traumatic to take some of these radial catheters in deeper inside the celiac access because of the angle that the catheter accesses the vessel. So that's where I think there might be a little bit food for thought and room for discussion.
As far as other reasons why I prefer trans-radial, we have found in our practice that since we've transitioned over - about four years ago I think we made the transition - it was a learning experience but the patients that had been with us getting repeat treatments throughout that time markedly prefer the trans-radial approach in terms of comfort and duration of recovery over the femoral approach. So I think that that factor also considered has pushed us to try to use radial as much as possible.
The one other thing I will mention since we're talking about limitations with facilities, at Brown at Rhode Island Hospital we have a common recovery area that we share with the diagnostic radiologists for all their biopsies and drainages so there's limited space when it comes to beds available for patient recovery. The faster we can get a patient sort of through the recovery period and discharge them onto the next phase of care the better off we are in terms of workflow efficiency. And we found that by using the trans-radial approach we've been able to cut our recovery times by as much as a third to a half. So we have markedly improved our efficiency just by switching over to the radial approach.
Again, it's been a learning experience, we've sort of perfected our setup. Our technologists were not cardiac-trained so it's not like they came with any sort of background knowledge. We've sort of just been piecing this together as we go.
Interestingly, your observations, there's some recent data on it. There's a study at MUSC that was there in the January of February issue of JVIR comparing trans-radial versus trans-femoral access in liver cancer embolization. And so they took patients who had actually been treated from both radial access and femoral access, and they surveyed the patients and it showed radial was preferred by the patients and decreased operator radiation exposure actually and there were no differences in adverse events, procedure time, contrast usage, or patient radiation. So I thought that was interesting. So how did you learn it?
Like you guys, when I was in fellowship this wasn't a big part of IR practice so I didn't have any specific training during that time. It was really all learned while I was practicing as an attending physician. I started off first hearing about it, becoming acquainted with it through sort of mini workshops and meetings, talks and stuff at SIR and various other meetings. And then it wasn't until there was sort of a push from our Terumo rep to really start bringing this onboard. Once we really looked at it as a practice, and again that was about four years ago, there was mounting evidence that it was being increasingly used as an access technique in IR sort of across the country. So we said, "Ah, you know what? Let's give it a try."
We obviously had to pick a few ideal patients to start off with. I mean everybody was a little hesitant, we're accessing a smaller artery here, we know that there are complications that can occur. So we were trying to find the ideal patient and I think that for each one of us in our practice that first that we decided, I mean we wanted it to be perfect. It was like a young male that didn't have any atherosclerotic risk factors. Good luck, right?
So it took us a while to kind of get into it and sort of dip our feet into the pool, but once we decided to do it we had a tremendous amount of support by our vendor. And really it started off, we were mostly learning from Terumo with the resources that they had. They have protocols in place. They were very, very helpful in training our nurses and technologists on the TR band in troubleshooting-type issues that they had seen in practice with other providers. So I think that without that and without that little bit of a push we probably would have been a lot slower to adopt the technique.
Hey Michael, can I chip in and ask a question to Jason?
So my question, whenever you guys were switching over, making the jump or slowly easing over to radial access, my question is how do you have the room set up where the monitors are and the patient's arm is?
So the answer to that question depends on whether or not we want the capability of performing a 3D sort of XperCT during the case. We initially always start off with the right arm down by the patient's side, the left arm that we access off a little less than 90 degrees. We found that when patients are extended to 90 degrees it's a little more uncomfortable for them so it's probably something like 70 degrees. The arm is fixed to the arm board, more or less the sort of metatarsophalangeal junction of the hand is sort of wrapped and secured down to the board. And then the wrist itself is prepped and exposed. We will actually lay a table out along the length of that arm board so that we have at least a little bit of a support structure for our flush lines and everything that needs to be essentially level and not tugging once that sheath access is in place within the radial artery.
What we found is that table height is a consideration. We've sort of prepped our side table that's adjacent to the hand so that we take one of those kind of blue guide wire bowls, flip it over and put it underneath the sterile drape to create a little bit of a pedestal so everything is more or less flush and level. And then there is another table that we put at 90 degrees to that first table just slightly down toward the patient's feet. So it sort of forms like a little alcove that we stand in: we've got the patient to the left, another table to the right, and immediately in front of us we have the outstretched arm with the access.
If we're doing 3D reformats or we're doing in XperCT we will actually with the catheter in place move the patient's arm. We'll move it up, believe it or not, we'll take the arm and we will extend it up so that the arms are sort of like as if you were putting your hands behind your head, they're sort of held in an angle. And we found that the catheter, it doesn't move all that much. We have to keep an eye on it while we're adjusting and we do it delicately, but by doing that we're able to get the II to actually do the correct spin either in propeller format or in a roll format to get the 3D information we need.
But there are various methods that are used out there in practice. I mean some people are using radial arm boards that go alongside the patient the entire time. So they'll access the radial artery and then they'll fold the arm in and keep it in parallel to the body and either reach over the body so they're working from the patient's right side or they'll stand on the ipsilateral side and work from there.
So you'll find variations in practice and I think it's really a matter of preference. But that's the quirky part of the radial access, is finding what you're comfortable with once you learn it. And you may try it a few different ways and say, "I like this way the best," and then you just roll with it. And you'll modify over the course of the first couple of dozen cases you do, you'll tweak things here and there to just make it better and better as you go. I guarantee that when you look at everybody in practice across the board, no one's doing it in identical fashion, there are all sorts of little subtleties on how they've improved the system for themselves and for their plant layout.
So I have one more question. So whenever we do radial access we do have the arm out, like you said maybe not at 90 degrees, that's a bit of a stretch for the patient, but then my situation is always what to do with my monitors. For whatever reason, it may be other rooms are different around the country, it's that our monitor setup, it's very much geared towards the monitors have to be on the other side of the patient that you're working on. I'm never able to get the monitors ... If I have the arm abducted to get the monitors in front of me and so I'm kind of ... As I'm working on the arm which is abducted I still have to turn my head over my left shoulder to see the monitors. Is that what you're also doing, Jason? Are you working off a slave monitor?
Yeah, actually so one of our rooms has that identical setup that you're saying where we kind of have to pull the monitor up as close to the patient's head as we can but it's still off to the left. So as you're working you can position your body so that you're working on the patient's wrist but you're more or less directing your body at a mid point between the monitor and the wrist so you're not craning your neck as much during the procedure. It's a little bit of a pain and to be honest with you it's not as nice as our other room where we have a slave monitor. The slave monitor is nice because you can just wheel it over and put it right in front of you where you're working and you're standing on the other side of the wrist and just looking straight at the monitor.
So two different ways we do it. I prefer the slave but I've learned to cope with doing it the other way. I don't have any neck problems yet.
Jason, I know you said everybody has a different way of doing this, but would you mind walking us through your approach to radial access when you're doing IO procedures?
Sure, absolutely. So obviously there are a bunch of technical aspects. Patient selection is key. And like I said, when you're first starting out you want to try to find the ideal patient that's going to have a suitable radial artery diameter, unlikely to have any plaque built up in the artery or any sort of unforeseen anatomic consideration as much as possible. It tends to be younger males that are the ideal candidates, particularly those that don't have all those risk factors. But since our patient population is pretty heavily weighted in the HCC realm, in IO we do get a lot of comorbid illness. So what we found is that as we have started going with this practice, even patients that we felt were not going to be candidates turned out to be good candidates.
And we can talk about some of the data toward the end of this discussion as far as the relative risk of vascular injury based on some of the pre-procedure testing stuff that we do. But what we found is that it's not as strict as what you initially think when you're starting. You don't have to be - I hate to say it - as careful as you really want to be in the beginning. There's a lot of leeway there and it's relatively rare that you're going to end up with a significant complication that's going to cause the patient long-term harm.
But in general, when we're talking about the technical aspects we always start off with an ultrasound to the forearm while the patient is in recovery. We'll check to make sure that the radial artery is sufficient diameter. I would set the threshold at two millimeters for a minimum diameter just based on the sheath size that we're putting in there, which we'll talk about. But in general there's also data to support that the complication rates are higher when the radial artery diameter is less than two millimeters. So we measure the artery, we do an ultrasound, we kind of follow the vessel up the forearm, make sure that we can't see any sort of radial loop or extreme tortuosity that might make it a difficult procedure. Even if you see a radial loop there are ways to overcome it, but again, it may sway you toward using a femoral access if it's a complete loop, for example.
So once we do the anatomic assessment with ultrasound we usually - you don't have to but we do - assess the completeness of the palmar arch by doing a Barbeau test. So the Barbeau test, I'm sure you guys are familiar with it, but it's basically an Allen's test used with a pulse oximeter that we place on either the thumb or the index finger or the hand. We compress the radial artery and observe the pulse ox's waveform. In general, the degree of depression of that waveform is going to tell you how well the ulnar artery is perfusing that superficial palmar arch. And there are various types of waveforms just based on the change. Type A or a type B is preferred. We have done a couple type Cs and haven't had any major issues with that yet but I would say that it's just a handful of patients that we run that risk with.
So that's sort of the overall assessment. If you've got a Barbeau type A or type B and the radial artery is two millimeters and the ultrasound at least to the forearm looks pretty good I'd say it's a go. And then we prep the patient up, bring him into the room.
Once we do the access there's a big debate about how you anesthetize the access site. To inject lidocaine through a needle you usually are running the risk of inciting spasm in the radial artery. And I would say that from a technical standpoint spasm is the one thing that could ruin your case, so anything you can do to minimize that chance of it occurring is going to bode well for more favorable outcome, at least in terms of the access site. So some people are using lidocaine cream on the skin and I believe there actually have been some studies that have shown that the rate of spasm in the artery is much lower when you're using the topical anesthetic. So if you have access to that I would recommend using it. In addition, there are some people that are putting nitropaste up on the forearm over the radial artery to try to even incite more vasodilation than what might be seem with the preliminary ultrasound at the beginning of the assessment.
So once we have the patient prepped, ready to go, we will put the local anesthetic on the skin. You're assessing with a ... It's more or less a 20 gauge needle 018 system. I use ultrasound for the access, I like the direct visualization. I'm not doing a through and through wall puncture. It's a single wall puncture directly visualizing the tip of the needle the entire time. Once you're in you get good return, you're threading your 018 wire, and the sheaths that we use are the Terumo glide sheaths.
The Slender sheaths in particular are designed such that the wall of the sheath is thinner than a standard access sheath that you would use, say, from a femoral approach. By doing that, by thinning out that wall what they've done is they have decreased the outer sheath size by about one French while maintaining the inner lumen diameter. So we're essentially using a five French sheath with a smaller outer diameter than what we would be seeing with a five French sheath in the groin. So with a two millimeter radial artery, that still allows for some blood flow around the sheath. The sheath's design, it's an 018 so it slips with a nice taper over that 018 wire. And I think that's key because what you don't want to do, in fact the thing you want to avoid at all costs with radial artery access is swapping out catheter sheaths. That's certainly going to send your artery into spasm. So it's nice that they have designed a sheath that inserts over an 018 system so it's a single, smooth insertion. It's also hydrophilic on the outside so that facilitates the access as well.
Once we get into the system and we've got good blood return through the sheath, we'll then put in a medicinal cocktail that is designed to reduce the risk of perisheath thrombosis and also stimulate some vasodilation. We use 2.5 milligrams of verapamil, 200 mics of nitro, and 5,000 units of heparin. We use a full dose heparin instead of the low-dose 3,000 units. There is some data to show that radial artery occlusion rates are a lot lower if you're using the full-dose heparin. So 5,000 units of heparin, 200 mics of nitro, 2.5 of verapamil, and then we hemodilute that. We will draw up in a 20 to 30 cc syringe, from the sheath, the patient's own blood to dilute the medication and then slowly administer that back through the sheath over the course of about two minutes. That's mainly to prevent that burning sensation that the verapamil can cause, that can incite some spasm, it can cause some anxiety in the patient who at this point is probably just crossing over that threshold into conscious sedation.
Once you've got the cocktail in you're kind of good to go at that point. I will mention that there is some data out there that instead of giving the nitroglycerin through the sheath some practices are using sublingual nitro. And they've shown that they can increase the radial diameter size by about five millimeters without a deleterious effect on blood pressure by giving it sublingual. It's an interesting point, we don't do that, but it's something that others have adopted in practice.
So again, your cocktail is in, you're ready to go, sheath is in. Now it's a matter of just picking your guide catheter. And as I mentioned before, this is actually a pretty critical decision. You want to know ahead of time the shape that you want to use. You want to make sure your inner luminal diameter is appropriate. Because once you have a guide catheter in and you're down in the aorta there's no way you're going to be able to swap this thing out for a different one without causing spasm in that artery. I've tried it, it's never worked out for me. So I would just say that as a point of fair warning that you want to give it some thought as far as the guide catheter is concerned.
I think guide catheters for us have been a little bit of a process of trial and error. We first started out when we were doing this using the Terumo catheters because we had the support of the rep there and we sort of just purchased all the stuff as a packaged deal. The Sarah, the Jacky catheters, they've got a great shape, they definitely move well, they respond well to torque. What we found was the problem with those catheters the inner lumen was not hydrophilic and it was actually just about at the threshold of what you would expect the inner lumen of a five French catheter to be. So if we were doing treatments where we wanted to use an antireflux catheter like the Surefire device we found that in passing that device through the catheter it would move well until it got to the tip and then it would sort of get bound up. And maybe one out of three times it would pass through and you were able to do the treatment and the other two times it would bind up on the fabric of the antireflux umbrella and just sort of destroy the Surefire catheter. So that was no good and that's also when we learned that you can't swap out catheters without causing a lot of spasm in the radial artery.
So just to reemphasize this process of introducing radial artery access in our practice was not exactly smooth-sailing the whole way but the idea is that you learn from the mistakes of others, and when you're implementing in your own practice, we've got some knowledge that we can add to the database to help you do it well.
The Launcher catheter is one that we kind of found with the help of Surefire because we were looking for a catheter that had slightly larger inner lumen diameter with a roughly equivalent outer diameter. So these Launcher catheters are known for their larger inner lumen. We talked before about getting good injection rates for diagnostic mappings and stuff, these catheters are actually fantastic for that. I mean you can get seven cc per second injections through them without any problem whatsoever. So you're certainly going to be able to do whatever you need to do from a flow rate standpoint and from a pressure standpoint with that catheter.
So long-winded answer, I apologize, but that was sort of like soup to nuts how we go through the initial approach.
Can we talk really quick, Jason, I'd like to hear about post procedure protocol for your TR band.
Sure, absolutely. We've sort of modified the recommended Terumo protocol, they've got one that they have on their website. But in general what we do is when we're putting the TR band on, and let me just start with that first off because this is a clear plastic band where there's a green marker on the inflatable balloon portion of the band that's supposed to be situated right over the point where your needle has to access the radial artery. So it tends to be slightly proximal to where your skin incision is actually made on the wrist if you do make a nick.
So you're positioning this balloon and what you're doing is, as you're removing the sheath, you inflate the balloon with almost ... It's pretty much a maximum amount of air. I mean we put in close to 18 ccs of air to begin with. But then, as you slowly release the pressure from this balloon, you're supposed to be watching for bleeding from the access site. Once it bleeds it can be really, really tough to see what's going on under that band.
So what we found is when we set up the TR band initially and we inflate we take a little four by four and we fold it over on itself and we kind of just tuck it in on the distal side of the band right adjacent to that green dot right near the access site where the bleeding is going to occur. And what that does is when you do get some bleeding the gauze actually just wicks the blood away and it doesn't sort of create this whole smudge in the window where you can't really tell what's going on anymore.
That was a trick that I actually learned from one of my fellows who had done some radial access in residency and we've sort of adopted it universally, so I'll throw that out there as a little pearl.
But in general, when we put this TR band on we're following the standard protocol where you inflate it with maximum amount of air, you slowly release that air until you see the bleeding. And then you're supposed to put in about three to five ccs of air in addition to that just to achieve non-occlusive pressure on that radial artery. We note how much air is left in the balloon, the total volume, we let the nurse know that, and then our protocol is that the band will stay on continuously for an hour. We don't peak, we don't do anything to it for an hour. At one hour we take out our first two cc volume of air. We do two ccs every 10 to 15 minutes. And I give a range there because I think it depends on a lot of factors, one of them being how much heparin we actually gave during the case.
I'm the guy that ... I give the one dose of heparin in the beginning, and assuming that this case is going to be an hour to an hour and a half I don't bother re-dosing the heparin. But some people do. So if the patient has gotten more heparin they may decide, "Well, I want to go longer intervals. I'm going to go 15 minutes with the two ccs of air." So that's the rationale behind the range there, but in general I think most people are doing 10-minute increments.
We do two ccs every 10 minutes. The nurses are trained to take the band down. If they see bleeding they put the volume back in and we let it sit up again for another whatever it, 10 to 15 minutes, before we give it another try.
After about another I'd say 45 minutes to an hour essentially you've got the band completely deflated. The artery is hemostatic, we remove the band. And so within two hours of the intervention most patients are ready to go. I mean the access site is clean, they've been sitting up in bed, eating, drinking, they've used the bathroom already because they haven't had to lay flat.
So just to summarize. An hour up and then every 10 to 15 minutes we take out two ccs of air until essentially the band is deflated and then we just remove it.
And I like Jason's like about lidocaine can sometimes excite vasospasm. But I found that one of the tips I've seen in the journal is if you use an EMLA cream, which is a combination between lidocaine and prilocaine, I think it's 40 milligrams EMLA cream. And then Jason also mentioned either the sublingual nitro or you can do 30 milligrams nitropaste. And you put both of those, the EMLA cream and the nitropaste, over the wrist and you cover that with a Tegaderm about 30 minutes to an hour before the procedure, I think that doing those things on the front end are going to set up maybe the neophyte radial accessor for success if they're looking to start out with radial access.
Yeah, I would agree a 100% on that and that's actually a very good point about setting that stuff up and getting it going about 30 minutes before the procedure. I think it does go a long way.
So one of my things about radial access that I was open to pick Jason's brain about and maybe debunk or flesh it out a little bit more is I think a lot of people worry about even the small risk of CVA or stroke or even TIA. And I didn't know if Jason had any anecdotal experience or if you want to speak a little bit to the literature about what are the actual chances of seeing any kind of permanent neurologic defect following radial access for below the diaphragm case.
So I would say operative phrase there being permanent neurological defect, exceedingly low. We know that the rates of silent stroke are actually fairly high, they can be as high as about 18% is what the literature says based on MRI data. A lot of that comes form cardiac catheterization though so I don't know that we know what the true incidents of subclinical stroke is for interventions performed from the left arm below the diaphragm. But the fact of the matter is that these tend to be these microembolic-type things that show up on diffusion weighted imaging. Patients are not at all symptomatic from it. So I think that the risk of stroke, I think it's just overplayed.
I, knock on wood, have not seen any clinically significant stroke in practice yet from any of the patients that I've done. I did have one patient that was lethargic from dehydration after a procedure, went to an outside hospital and because she was lethargic they thought maybe she had some neurological symptoms. They ended up doing an MR and it did show that she had some little punctate areas of diffusion restriction in the parietal lobes. But again, I mean from a neurologic standpoint no motor deficit, no sensory deficit. She was clinically asymptomatic from it.
So it's there, it's a risk, but with appropriate heparinization even that one time standard dose of 5,000 ... My belief is that we're sort of overplaying this and it shouldn't be as much of a concern as some people make it out to be.
Since we're on the topic of complications, I mean we have seen radial artery occlusions post procedure. They're all clinically asymptomatic with the exception of one in our practice that was not. I think that they report radial artery occlusion at a rate of I think it's about 4 to 10% or something based on the cardiac cath data. But they do say that the use of standard-dose heparin, 5,000 units as opposed to the 3,000 unit dose of heparin at the beginning of the case is associated with lower rates of vessel occlusion.
I'm convinced that the cases that we have seen where the vessel went down, although the patients were asymptomatic it does preclude access from that artery later on to do additional treatments unless you want to sort of go through the creative gesture of sort of tunneling through there and using it anyway, which I know some places do. So in general, you could say there is some risk to the patient in that it may sort of relegate that to a femoral approach for all their subsequent interventions, but from a symptomatic standpoint it's very rare that these patients end up with hand ischemia.
But it's great that we have these forums like this to discuss because ... I also looked through the literature prior to this discussion. It's amazing how much of this is heavily related to the cardiac cath data, and we don't have a lot of it do go on from an IR standpoint with below the diaphragm intervention. So I think there's room there for more study but I think that what we're going to find is that we've sort of put a lot of emphasis on concerns that may not be legitimate in the long term.
Well guys, that was awesome. Thank you for taking the time and joining us for this discussion.
Of course a special thanks to today's sponsor Surefire Medical. Surefire's pressure-directed Infusion System improves selective delivery of embolic material and minimizes non-target embolization. Learn more at surefiremedical.com.
Thanks again everyone for joining us and we'll catch you on the next one.
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