Transcription
So this morning, we'll try to understand a couple of devices which we commonly use in interventional radiology. Now, whenever we do a procedure, we understand one simple fundamental, and the fundamental is that the closer we are to the site of pathology, the more stability we get for the use of microcatheters and wires and devices. So when we do a neurointervention procedures, the first device that was available is called a neuroguiding catheter. Remember one thing: the neuroguiding catheters were excellent at one point of time, but today we do not use it as often as before, and I'll tell you the reason. So this is a neuroguiding—this is actually from uh, Cordis, and it's called the Envoy. It is a good guiding catheter with limitations, like any guiding.
So one of the things we see: they don't have multiple zones. If at all you want to talk about a zone, this has got just two zones—one part which is somewhat soft, you can see this, and a stiff part here. All right. So the limitations of this is, since we have got just two zones, and this also is not very, very soft, the maximum you can take these guiding catheters is to the level of the petrosal segment of the internal carotid artery. Even that can become very challenging if we have got a bend or a tight tonsillar loop, because these catheters would end up in inducing severe spasm. So this was the limitation. You have a vessel which is very torturous, and in a very torturous vessel, the thing is you would like to cross all these bends so that our access is better.
Having said that, why is it necessary to have a guiding catheter at all? Why don't we take a microcatheter right from the ostium of a vessel? Now, it's very simple if you understand the logic: when a microcatheter goes inside a tube like this, the microcatheter remains more or less straight. So the forward thrust that we gave onto the microcatheter is transmitted in line with the microcatheter, and so the tip will move forward without much of a problem. Now imagine the same microcatheter is put in a vessel which is, say, like as thick as my thumb or thick as my finger. So what's going to happen in this situation is the microcatheter will start taking an S-like bend. You understand what I'm saying, right? So when it takes an S-like bend, the pressure transmission will not be in line, but it'll go in the direction of a loop. If I have got a microcatheter here, I can just show what I'm talking about. See, so this is a microcatheter. Now just imagine this situation—I'm just showing this to you. Now if this is straight, when I give a forward thrust, it's going to move up, right? It's pretty simple; it'll move up straight. Now if I've got a loop like this—suppose this is a kind of loop they will develop in a large vessel—when I push here, the air pressure will exit on the apex of the loop, and after a certain amount of pressure built up, only then it moves forward. So this will result in a very rapid, jerky movement. Also, when I want to reposition the catheter, first the loop will straighten and straighten and straighten, and suddenly the whole catheter will drop back. Now these are very disturbing when you're working in vessels where the tip has to be aligned exactly, exactly close to, say, for example, a ruptured aneurysm. You don't want a sudden forward thrust, and that is why we require these devices as distal as possible. So we, we loosely use it as a term as support.
Now, having said that, let's just go back to the guiding catheter. Now, like I said, the guiding catheter's problem was it is a reasonably stiff device with a little bit of a soft tip on the end which was supposed to actually help us. Now this has got a braiding that is there on along the main shaft. So if I cut it, I'll show you the, the, the things that happen over here. So let's take a scissor. So if you try to cut this point, you'll find there is actually steel braiding. It is probably difficult for you to see it, but this is braided, and you can understand the property—it will never break, but it gets badly kinked. Why does it kink? Kinking is a property of the braiding. If there's no braiding, it will break. This doesn't break. So we got braiding so that I try in every way, it doesn't crack. It will get twisted, but it won't crack. So it gets twisted because it's based on the material that is used for braiding. Most of the companies, even today, use stainless steel as the braiding material. Now once you use stainless steel as a braiding material, there's an advantage in the sense it gives very good pushability because the transmission is so good that you can push. Now trackability is the ability of a catheter to go over a wire. Now that trackability is determined on how flexible a catheter is, and that is why these catheters were stiff. They could be pushed, but was not flexible. When you come to this distal part, there is actually no—you can actually see the tip of it will have nothing; it will break in your hand. You can see that here—the snip tip just came off into the hand. So there is nothing here. This can't get, but beyond this there is actually a coating they use to make it soft, and the braiding starts actually stopping towards the end. So based on this, so basically we have a much thicker polymer, then we got a braiding. The braiding here comes all the way to the tip. I'm just showing you here—it's like you cannot break it because of that. Like I said, whatever you do, you can't break it. So what they have done is they have changed the material so that it becomes softer, but the braiding is there, and the braiding has a big problem that it gets completely kinked. Can you see that? It's completely flat. So the problem with the guiding was it was useful for to a certain point of time. Even today you can use it if you do not want to go beyond the petrosal segment.
Thus came a set of catheters that would completely revolutionize the way we were working. Remember, it's also in this—the hub will tell you most of the time—uh, it's six French, but it's also got a 0.70 lumen. This is important because it determines a number of devices that can go through this. Okay. So then came the first device that would change the way we worked, and the first device that we got was a device called the Neuron. I'm showing this to you. So see the difference between a Neuron and a guiding catheter is just the way it was constructed. So the construction in a Neuron is based on the fact they got multiple zones. So they have got a first zone which is made of transparent material. Inside this, they are running a spiral—not a weave—for the matter we saw in in the guiding catheter; they were running two strands of steel as an X running all across that gave tremendous pushability. Now the problem is trackability is much better if you change this X and make it a spiral. So what they did in this product, Neuron, is they have got a platinum marker which is basically a tight coil. After that, they have got this coil coming, and the pitch of this coil changes. For example, distally the pitch is 0.004 of an inch. As they come proximally, it will become—uh, actually—distally it is 0.008, then it becomes 0.004, then it becomes 0.001. So as you come proximally, it gets stiffer because of the braiding. You can actually see the braiding over here. Can you look at it here? Maybe you can see it. Um, I'm not sure, but if you can make out the braiding, I'll just try to get the light from another direction, hoping that you can actually see the braiding. You may be able to see it better now, and this makes you understand that this is the pattern that they use for actually enabling us to do the procedure better. Okay. So, uh, now it's very simple to understand: when I reduce the density of the braiding, then it becomes a lot more flexible, right? You can see that it's a lot more flexible because, and as I go back, it becomes stiffer and stiffer, and right in the back it is really stiff. So this is what we mean by variable transitions. So the variable transition is created by a combination of two products: one, the density of the braid, and the second is the density of the polymer that they use, and most of the companies actually will use a PTFE liner inside, and here I am not even seeing the PTFE liner if it is there, but PTFE liner's biggest advantage is this that if you want to pull in a metal device like a stent retriever, then without a PTFE liner, it will tear. So you can see this that in the distal end there is no PTFE liner because this is meant to just take microcatheters, balloon catheters, and nothing more stiffer.
So is it a perfect catheter? It is good in many ways. It gives us a very good pushability because it's got a stainless steel spiral running all the way. Uh, its trackability is improved a lot because it has got a spiral loop which allows it to definitely take much better curves. So you can see, but let's have a look at a problem with the Neuron. The problem with the Neuron is if you bend it, it is destroyed. Have a look at it. Can you see it's completely gone? It has become a useless catheter—cannot be used at all. Have a look at it. Okay, and I'm going to talk to this in greater detail now. For example, you are in a situation where you got a tight loop—it is like this—this is what will happen to the Neuron. You understand this problem. So Neuron is good, but remember the problem of Neuron is it can get completely deformed; it's become like a ribbon over here. Now from here, I want to show you another distal access catheter. So remember, Neuron is still good, but be careful when you're taking Neuron over tight loops, because as you push and pull, you may kink it, and it may get completely destroyed. So, and this is the trade-off they got because of a fantastic pushability because of stainless steel and a spiral, because of this, but the problem is right to the end—it can destroy the catheter completely. It looks pretty disastrous, I know, and I know that the Penumbra may not be happy showing you this demonstration, but the bottom line—you must know this is the problem. So even when you insert it inside, uh, remember this is a problem that can take place. Now I've got another distal access catheter called the Navien. Have a look at this. Looks black in color, not transparent, and it has also got a spiral. Now it's difficult probably for you to see the spiral because it's not transparent, but if you look carefully, it's also got a spiral, but I'm going to show you one property of this. See this—I'm pressing this. Can you see that it's bouncing back? Can you see that it is bouncing back? Can you see I do this and it comes back? Now tell me what would you choose? Would you like to use—see this catheter—you know, except for exactly the final tip which has no braiding, everywhere else I do this and it bounces back. See, whatever I do, I can't, and if I do this—have a look at this—you do this to it, it doesn't—pretty amazing, right? Right, and it straightens up again. So you can do a very interesting maneuver with this; you can actually even make a knot. See, this is a knot—pretty tight—and you can still pass a microcatheter through this. Seriously, I'm not—I'm not really paid by Medtronic to tell you this, but just want you to understand why certain devices work better in certain places. So here is this—it is—we are wet the catheter. I hope the micro is also wet; otherwise, it won't work. Let's just try just to make you understand how this works. So remember all the catheters have certain some simple pro—uh, facilities. All of them have a lube coating. All of them are made with different polymers, but the braiding in this is Nitinol from end to end. Remember now what was the difference? Penumbra use stainless steel because they felt pushability was the most important thing. Can you see that? Is that astounding? It's pretty remarkable, right? Let's just come back a bit and tighten this even more and see what happens. Have a look, and still it goes through. So it's very easy to understand without much complication that if you have a tight loop, and Navien is going to be your choice if you want to use a distal access catheter. Right now, understand that all the other companies when we go for distal access continue to use steel except Navien, and Navien was basically the first company that decided to do a braiding end to end using Nitinol. So understand the problem is you may feel that the pushability may come down, but in real practice we find because this goes through a long sheath, pushability is not such a big issue. Now when Penumbra created the Neuron, they actually initially thought the Neuron will be used without using a long sheath and directly we'll be taking it through a short sheath and then pushing it, but finally we all use a long sheath, and the pushability factor is not such a big important thing. So I wanted to get this thing—it is purely the first property of what is the braiding—same spiral braiding, same distal lubricious coating, same zones they have used—they say five zones, 12 zones actually doesn't make a big difference to us because each company says they got different zones, and of course we have got uh, the Cat 5 and Cat 6 which they call as zoneless just by continuously changing the density of the spiral. But I want you to get this—I hope you got this clear—the big advantage of Navien is it gives a good lumen like all others. It's got a tip which is soft, but more importantly, it gives you this, and like I said, this is a property through and through—it is—they don't use steel anywhere. So wherever you go, even if there is a kink, it can straighten up as soon as you pull it because of the Nitinol braiding that is there in this. Now from here, and so remember Navien's got an extremely wide lumen; it easily takes two devices across, and it's a very good device for taking through very tortuous—and any day better than using a Neuron, but Neuron is pretty straightforward too if you don't have a 360-degree loop that you have to take.
Now the other distal access catheters that you have is the Cat 5. Now where do you position Cat 5? I just want to show you a Cat 5 versus a Cat 5. So this is a Cat 6, I think. This is a Cat 5. Okay. Now this is a Cat 5. No, it's basically Cat means Catalyst. So what they have done is they have made a catheter very, very similar to that of the Neuron, and here they've again used a distal spiral. You can see the distal spiral, and uh, it's very easy to know what is the material—not a problem at all. You do just squeeze it. If it is squeezed and it stays squeezed, it's steel. So can you get this point? It is not squeezed, and they have used alloy which is again a Nitinol-based alloy which prevents this kinking to take place. Can I get it? It doesn't flatten. So that makes it an extremely good distal access catheter. Now the advantage of Cat 5 is Cat 5 comes in multiple lengths. You got a 105 length which is the one that you would use if you want to do an interventional stenting. Is the one you would use when you want to do even—you can do a coiling, or you want to put a device like a WEB device, or you want to put a device like the Contour. All of these will do very well because it's extremely trackable. It is again a platform where they have used a variable form of operating, and they run it all across. So they haven't got a continuous braiding actually which runs from end to end. It's a spiral, but it is only a spiral; they are not really used anything beyond it. So like I said, though theoretically these spirals give you one big advantage—it will prevent the tip from collapsing. It's also very trackable, but pushability is supposed to be less, but you do not really feel that problem because we go through a long sheath. So this is one of the best devices when you want to go really distally, when you want to put a stent, or you want to use, like I said, a device like a Contour, and they come in two lengths. So decide your length properly. If you take a longer length, the microcatheter tip beyond it won't come. So if you're going to use it for a procedure like a stenting, to use the shorter lengths that are available. Now Cat 5's advantage—it is that it is a very trackable catheter. It's extremely good, and again it's got multiple zones, like today's any catheter. Like I said, you'll have the first zone, the second zone, and it gets stiffer and stiffer. It's very simple to see this. I mean, just you all you do is cut it at every point, and you can make out how the stiffness changes. Otherwise, you see the hub will be the same, the restrainer will be the same. I just want to tell you the property that this does not kink, and because it doesn't kink, it's a very good device to go across this thing, and even for the matter you can make, you know, this knot with this, and you'll find this also takes a knot, and this is because they use a combination of a cobalt Nitinol braiding which is a little different from any other company, right? So the same technology has been carried on to their suction catheters, and I'll show you for some reason what we see as a dark catheter is nothing but an extension uh, which was extended to become an aspiration catheter. Now this is the ACE. ACE was the first suction catheter that came into the market, at least in India, and we were very excited about it, but again the one thing they have done is they got a fantastic lumen they use. Okay. So have a look at this. Now what's happening? This is the problem with Penumbra. Penumbra still clung on to stainless steel purely because of the pushability, but you see the problem—this is an aspiration catheter, one of the best aspiration catheters, but it kinks. Now this kink may not matter too much when it is distant. Remember, inside this there is a sleeve; the sleeve is what protects it to do a Solitaire-like technique; otherwise, you can't do it. Now see this—it, it flattens all over, and because of this again in a very torturous anatomy, if you put a tight loop, you will find it goes off. See this is the problem—it gets permanently kinked, cannot straighten, whereas in the others it can stay. So remember one thing—steel gives you the best pushability, can give you very good trackability, but uh, the spirals give you good trackability, but they are not kink resistant. So all over, you know, and this is the reason you'll find if you're working in a complex anatomy and you do a pulling and a pushing, this catheter may completely get deformed and go. I want to show you another catheter which is made by the same company, Medtronic. So this is something recent they did; this is their latest thing, and I'll tell you an interesting property here. This is a catheter which even any hold you find seems to be a lot more springing. So how did they get this effect which seems to be a lot more pushable? See, when you hold it, you feel it practically leaping in your hand, and look at it—the distal is super floppy—much more floppy than anything else. So what these people did—now I want you to look at this—I'm gonna bring the light on the other side. I hope you can see it. I want you to have a look. Can you see the braiding here? This you can look like excess. Can you see that? Now this is a compound braiding that they have done when they used two forms of braiding. The first braiding is a spiral braiding which they've done—you cannot see properly in this—along with the spiral braiding, they have also used a double X braiding. Now and the complete platform is Nitinol. So the thing is how do you get a profile when you do these braidings? I told you last time it's actually not by round wires, but it's actually by flat ribbons. So you see, right up to the distal end, they have run this right up to the tip. Now what have you achieved when you give a braiding which is like an X? You're going to make it very pushable. When you make a braiding which is like a helical, you can actually make it very flexible. So by reducing the thickness of the material and able to build a compound braiding, they made this an extremely good catheter, and I believe that probably this is the best catheter currently available in the market if you want to do suction. The reason is it can cross the most complex anatomy because it got both pushability and trackability by combining it, and because it's a Nitinol platform, you have the advantage that it will not kink. So this is what I told you—know whatever you do to this catheter and compress it—you do this—it comes back again, which is impossible. The other thing is I've just done something crazy as this, and I bring it back—it comes back again—and it's very easy for us to understand. Now this looks much safer when you go through complex anatomy of any sort, and along with that they are given a sleeve on the tip, but remember the final tip is the only place where this cannot happen, and it is protected by an inner sleeve. Now when all the other companies stuck on onto a PTFE sleeve, these people or Medtronic decided to put a thermoplastic sleeve which is thinner and also tougher. Now it's mandatory that we use every device today for suction which has got an inner sleeve because we're gonna pull the stent retriever inside it. Will you take Sofia for the matter? Sofia is very trackable, extremely well designed, but the problem is the tip doesn't have the sleeve, and because it doesn't have a sleeve, when you pull it back, it will tear the distal end of the Sofia when you do a Solitaire technique. So for Solitaire, I need that. So have a look at it—like I said, you know, you can try the knot test again if you want and see—it will work perfectly. Okay, because—and this will go through. Okay. So this is because of this Nitinol platform. So the catch is little—makes it a little softer. Will it really track? But we know that today they track over the 2.7 microcatheters. So along with that, if you are taking a good to a 2.7 microcatheter, this will work well. So this has got—they say 12 transitions—actually you can see it's easy to understand how they make—how the transition keeps changing to stiffness, and you know it's a little more stiffer here, then it gets more stiff, and down here it's a pushable segment which is very stiff, but remember end to end it is Nitinol; it's a dual braiding platform, and these are the only people who have got a dual braid. Now if somebody say how, then is Cat 7? Cat 7 works fine, but it still works on a helical braid. I, uh, if I have a Cat 7, I'll just get one Cat 7 and show you also. Now Cat 7 is also a good catheter, but to me, I think in terms of technology, the best catheter that we have in terms of technology is the REACT, and and I think that with time we hope to see REACT proving itself to be the most trackable catheter and the most kink resistant. So here it is uh, if you can—I'll try to bring the light again—this is Cat 7. The braiding over here is again just a spiral braiding. Can you see that? It's a single spiral braid. They do what's called a continuous braid. They say it is transitionless, meaning you cannot feel the transition. So it's got infinite transition as from distal to proximal the braiding platform will change. Okay. So if you see a catheter, you can now pick it up and have a look, and very easy for you to figure out what I'm saying at this time, right? That this is a concept. Now you want to know what are the materials—take…
Any catheter: See if they are kink-resistant or not. See if you see just the distal tip, but beyond that, they resist kinks much better than the ACE. See that I press it, I leave it, I bend it down, I try to do anything to it; it bounces back. Once it bounces back, you know that the alloy cannot be pure stainless steel. Have a look at that. Now that is what makes it different. It is, uh, you know, some of these alloys are not just pure nitinol, but it's a proprietary and, uh, I believe they may be they are using a combination of cobalt along with the nitinol to get this property. But it's an excellent property. See that you kick it; you're completely kinked by twisting, but it comes back, comes back to normal again. So again, an excellent catheter in terms of property, but the only thing: it's a single braiding. Single braiding technically makes it more trackable because it can take the curve better, but somehow we have seen that REACT has combined both a combination of two braids, running the X-sprayed and the helical braid, both of them working together, and probably you may find that does better in difficult anatomy. But you know, the usage in India has still not been very high, but in our hands, we have found REACT an extremely good catheter.
REACT 71 also: Inside this, the inner sleeve is PTFE, whereas in all the other companies, uh, all the companies use PTFE, rather accept the REACT 71, which uses a thermoplastic material. Right. So when you take this catheter, remember the lengths; the length of all these catheters are much longer than the conventional DAC catheters because they are meant for suction. And so this is a CAT 7 0 6 8 132 centimeters long. So remember when you're using a Y connector, you lose another five to six centimeters. So today, companies have started bringing longer micro-catheters also, catheters which are longer than 150, which will give you the digital access that you need.
So hope you got some idea about how the distal axis catheters and aspiration catheters are constructed. Once again, just to summarize: If you are taking a distal axis catheter like a Neuron or you want to take a Navion, remember a lot of wood would depend on how torturous is here and at if your vessel is really torturous, I would prefer to take a Navion purely because of the nitinol platform, which will ensure that it doesn't kink in the tightest loops. Whereas if not, I can do very well with a Neuron or a Fargo because we are talking about pushability which will be available; they are superior to the guiding catheters because we can go all the way up to the cavernous segment and at times even cross the cavernous segment, especially the Navion, very often crosses the cavernous segment and you can go beyond it. Now if you want to go into the M1 segment to do a procedure and you want to use a DAC, CAT 5 is extremely good unless you want to put two devices inside, where then of course you have to change your strategy and probably use, uh, a Navion or, uh, a Neuron.
Having from there, we talked to you about the aspiration catheters, telling it's exactly the same platform. For some reason, the companies have used exactly the same platform. Penumbra used stainless steel; continues to use stainless steel. Penumbra's Neuron kinks and gets flattened, and the ACE also kinks and gets flattened. Whereas if you look at EV3 that made Navion, from there, Medtronic purchases off; they take the technology and they create REACT, which is again a nitinol platform; has the same property except they put a double braiding into it, change the inner liner, liner to be thermoplastic and got a fabulous catheter. Same time, if you look at CAT 5, CAT 6, the tip doesn't, uh, kink at all as you showed; it doesn't flatten, and they got the same platform going on to the CAT 6 and to the CAT 7 with the same properties. So technically what I'm trying to say is the same platform has been used by both the companies, all the companies for the digital access catheter and also for the aspiration catheter.
Now once you've got this, you may say, so I understand that we have got these distal axis catheters and the aspiration catheters, but why do we need long sheaths at all? Now it's easy to understand why you need a long sheath if you understand the body is not in an absolute straight line. So when we come, for example, into a segment in the carotid arch and then we enter into the internal carotid artery, this is the bend we are going to take. Now if you're going to have a bend like this, remember when you try to push now it will tend to go into the arch; you get this; it's going to move into the ascending aorta as you push it. The only way you can, can avoid this, this if you have something that straightens this completely and does not allow this to take place. So for that, we need a long sheath; you get this point. So that's why we found out that it is much safer to work in the head and neck region with a long sheath to prevent this. So what's happening: You're doing a procedure; you're trying to push, push, push; actually instead of getting the push, push, it starts going down, down, and a point comes when it pulls the whole device down. To avoid that, you use a long sheath.
So when we started with long sheaths, actually we did not have a dedicated neuro long-sheath, and we worked with the Cook sheath, which is called the Ansel sheath, and I'll show you an Ansel sheath; I'll show you the limitations of an Ansel sheath and why the neurosheaths came into practice. Now the Ansel sheath first of all did was not created for the brain, because it was not created for the brain; the distal ends of the sheaths were really not soft, and I'm going to show it to you right now. And so if you're going to use an Ansel-like sheath, it's pretty okay provided you limit it to the distal common carotid and you don't go into the internal carotid artery. So now this is an Ansel sheath, okay, this is a Cook sheath. What you have over here is, of course, a five French sheath, but technically we'll use a six French, but it is the same, but the construction is exactly the same. I'm going to show you: The first problem is they have a valve over here. Now I showed you the problem of this is that when we use these saw-tip devices like the Neuron which permanently gets kinked or the Navion which temporarily gets kinked or even for the MATTA CAT 6, this valve is not a good location. Now when you try to insert it, we may have a problem. So ideally, we need a rotating valve out here which will allow us to, uh, take it in easily. The second thing is it has, uh, you can technically call it just two transition zones; this is a kind of a slightly soft, after that is fully braided, and you know the braiding runs through and through; you can actually see the braid; it is a helical braid. And here the problem is that it's a very stiff catheter. So if it goes into a bend in the internal carotid, this tip will dissect the vessel. So you can use this; it's pretty good because it's stiff. Now see what happens: You have this catheter like this across the arch and into the left carotid artery. Now when you push it, devices will go distally through it and it will not push this device because this is kept fixed; you don't move it once you got into a secure position. And that is why for any neuro procedure where you cannot have that neck in view all the time, it is better to have a long sheath. So today we would use that.
So the only advantage, if you ask me, of the the Cook sheath is that it is cheap; other than that, the disadvantages are many, especially if you go into the internal carotid; you can dissect, and of course it got a very tight valve making it difficult to take it. Having said that, we still use it a lot in our department primarily because we realize keeping it in the distal common carotid we can do a great job. The only place you should never use it is if you have a point where the cannot take bifurcation is very tortuous; for example, the ECA will be coming at 90 degrees to the common carotid, and the ICA would be coming at another angle which is close to 90 degrees. Now in that situation, when you push a distal axis catheter like a Neuron or a Navion, it will buckle into the external carotid artery. So because the long sheath is still in the common carotid at this point, it will buckle, and it's so in at least in those it's mandatory that you have a dedicated long distal access sheath or a dedicated, uh, device like the NeuroMax. So again, we have to thank Penumbra for the concepts that they developed which others technically would improve.
So this is the long sheath from Penumbra which we call the NeuroMax. Now the first thing what they did: They're going to use the same technology; they'll use steel braiding, but they have given at least three zones; this is a real stiff zone, then you got an intermediate zone and a much softer zone here, and this is what makes it safe. So technically you can take a NeuroMax safely up to the petrous segment, and of course they say you can take it across a loop, but remember they still have not got out of stainless steel. So have a look at the problem; can you see that it is smashed? Now this is something I know that Penumbra will not be happy when we talk about this, but it's to highlight the fact: It's time Penumbra started thinking differently and changing from their steel reinforcements and moving to nitinol. This is crazy; can you look at it? Nobody wants to use a device that can get so messed up if it goes through a tight loop. As long as there is no Type 2, there is no problem; it will go, but if you're going to go into something where the loop is going to be like this, you know, in the tonsillar room, it's going to be pretty messy and not a great idea, and honestly we would still say it's not a great thing to, to use.
Then comes the Infinity platform, which is also a guiding platform, a long sheath platform which is made by Boston, I mean Striker. So this is also very similar; again got these multiple zones; it is, you can have a look why these behave this that, and always know that these long sheaths come in different lengths. So if you're going to work and you think that you're not going to go very, very high, try to take a long sheath with 80 centimeters, but you're going to work with stroke for that matter where you want to drive your suction catheter much deeper, you go for 90 centimeters. And this is the steel braiding; this is really stiff; this is 80 centimeters. So you know that this technically, theoretically doesn't need a long sheath, but we still use it because this stiff end is going to sit right inside the arch and the carotid, but the reason we use it is by some chance it kicks out, it's not safe. So we would recommend a long, I mean this is a long sheath; I'm sorry, what I meant is that, uh, this is made perfect if you see, uh, and it is perfectly made; gives all the support that you want at the point where the turn takes place from the carotid into the the um into the carotid artery from the arch, and thus you can understand the property of this thickness versus the softness is what makes a difference.
Now remember one thing: If you have taken a long sheath like this which is 90 centimeter, the soft segment gets longer. So if the soft segment is going to be at the junction between the arch and the common carotid artery, you'll have a problem now because suppose it is like this, what's gonna happen? It'll easily buckle out; you get this point; it's going to buckle out; it'll going to be a problem; you'll kink it; you'll destroy it. But remember this also catheter, these catheters are kinking because they use stainless steel, and the reason they use stainless steel for this is because of the much better rigidity for taking a device, but technically, uh, these are in real life a little more trackable, I think, across the bend compared to the, uh, NeuroMax, but otherwise there is not much of a difference. The only difference comes in the Ballast long catheter, which is called the Ballast. Now Ballast construction is a little different in that the stem is a little more tough, so this will play a role only in one place, and that one place is when you do a translational approach. If you want to do a translatable approach and you want to use a long sheath, the best long sheath to use is the Ballast. Now why is it that we are talking the Ballast is the best long sheath? It's primarily because they have got a better transition in the segment which is from the innominate artery to the left keratin. So that point you've got a curve; it somehow works fine; it is otherwise very similar in construction when you do a procedure. Right. So, uh, to summarize once again: The ideal long sheath is a long sheath which can go all the way to the petrous, but remember one thing that the trade-off: You should not end up in such a situation that the soft part of the catheter is still in the arch. If your soft part is in the arch, it will buckle into the ascending aorta when you do a procedure. So choose your length wisely. All the long sheaths have nearly the same property; they all made with stainless steel reinforcement; they got multiple transition zones, but to understand for us there is one stiff part and a soft distal segment, and the distal segment can go safely up to the petrous. If you're taking a tight loop, remember long sheaths are not the ideal device to go around 360 loops. So often you can come maybe up to halfway through, but beyond it they're still making the best long sheath to be used in the trans-regal route is the Ballast because they have got a stiffer segment which is proximal to the soft end which gives us support that is necessary to go up. Right. So this is a little bit of a summary on devices.
Today we realized we did not do any neuro work without a long sheath; we also try to use distal access catheters through that all the time. I told you why we do that; it's to prevent those bends that take place inside the parent artery which takes away our property of pushability and rather it becomes more and more redundant. Having said that, just a few words about the use of long sheaths in the periphery. Long sheaths are not only for use for support; long sheaths and digital axis catheters also give us a platform through which we can inject contrast. So in the periphery, we use it more for also taking test injections and check injections. The classical places where we use the long sheath and the periphery is when you do a crossover procedure and when you want to do a procedure in the SFA or down in the posterior TBS where it can give support as well as gives you the ability to test inject, especially if you're using a monorail balloon and wire. Remember you cannot work without a long sheath or a guiding catheter. We also use the long sheath and the carotid arteries both for support and for doing a test injection, also for any vessel that arises from the arch like the subclavian artery. The commonest sheath that we use in the periphery is the Ansel sheath or the the Cook sheaths which works extremely well in this location, uh, because right there we are not looking so much of a delicate, uh, segment like the intracranial carotid artery. Also the same long sheath can also be used while doing, uh, SMS stenting or a celiac axis stenting, uh, because they all work fine because they can go over it and you can track it and, uh, take your stent across. So this is a little bit of a summary; I hope that you've got some idea about the devices. And the most important thing now for all of you is to take these devices in your hand and try everything. We did; a company guy may tell you many things; take those long catheters or the DAC catheters or the aspiration catheters or long sheaths; squeeze it in your hand; see if they remain compressed or they bounce back. If they bounce back, the material is nitinol or an additional alloy of nitinol; if it doesn't bounce back, it is stainless steel, and then you decide in which area what would you choose. Stainless steel continues to be the most pushable device, and like I said in the micro-catheter, the most shapeable device, but remember the problem also is that if it's kinked, it won't straighten. Nitinol is a much more softer device, but it is kink-resistant. So I hope some fundamentals are clear with this. Thank you so much.