Transcription
Hi, this is Manus Berlakis from the Minneapolis Heart Institute and the Cardiovascular Innovations Foundation, presenting video 30.3 for the Manual of Percutaneous Coronary Interventions. This is a video that discusses the use of guide catheter extensions. Guide catheter extensions can facilitate several of the 14 steps of percutaneous coronary intervention, such as engaging the vessel, performing the diagnostic angiogram, wiring the lesion, preparing the lesion, and stenting. And they will be discussed in detail. It is the third of the 22 categories of equipment, and there are four of them currently available in the United States as of 2020: the Guideliner, the DropLiner, the Godzilla, and the Telescope. And there are more of them available internationally, such as the Guidion and the Heart Rail 5 and 6 system.
These are the currently available systems in the United States. The Guideliner was the original one; it has a 25-centimeter cylinder and then has a 108-centimeter push rod. There is a half pipe that helps equipment entering into the digital cylinder. The DropLiner is very similar but has the difference that the cylinder is shorter, and there is a balloon built in on the push rod that can be used to trap the guide wire and remove equipment without having to use another trapping balloon. The Godzilla, very similar, has a digital cylinder and a proximal push rod, and then the Telescope, very similar as well with the other two catheters. Here is the image of the Guidion. All of the catheters, with the exception of the DropLiner that has a shorter cylinder, have a 25-centimeter long cylinder that can be used to deeply intubate, intubate the target vessel.
So why use guide extensions? And there are many potential uses. The most common one is to facilitate equipment delivery. This is an example of a case in which facilitating delivery is important. This is for balloon and crossover lesions when the wire goes through, the balloon does not. After trying a small balloon, then the next step is to increase the support, and the guide catheter extension is a critical component of that increase in support. This is an example showing how a deeply intubated guide catheter extension can facilitate the support for equipment deliberately into this softness vein graft. Sometimes there can be a maneuver in which the guide extension is advanced deeply into the vessel, and then the guide is resting against the aortic wall, facilitating extra support.
This is an example of a coronary perforation in which a graft master could not be delivered through that area of perforation because of calcification and tortuosity, which is not uncommon for cover stents, especially the GraftMaster. But using a guide extension, the GraftMaster could be successfully delivered to that area of perforation and then successfully sealed that perforation. This is another example of a patient with recent cardiac surgery with reimplantation of the coronary arteries in which there was a proximal perforation in the immediate post-operative period. The guide extension was used to deliver the cover stent that successfully sealed the perforation.
A second potential use is to facilitate coronary engagement. This is an example of a patient in whom engagement of the left main was extremely challenging. Eventually, a guide wire could be advanced into the vessel, and then over this wire, a guide extension was advanced deeply into the left main, which facilitated engagement and performance of angiography as well as PCI. This is another example in which there is an anomalous right coronary artery. Using a guide extension was critical for engaging that vessel that comes from the left coronary cusp. So for challenging engagement, guide extension can quite often provide a solution. This is another example in which there are bifurcation lesions in the circumflex, but visualization is suboptimal. Using a balloon, a guide extension was delivered to the mid vessel, and now after injecting through the guide extension, there is a much more clear delineation of the anatomy of that circumflex with the tandem lesions. This was also very useful for delivering equipment, balloons, and stents and then achieving a nice final result.
So equipment delivery is number one; facilitating vessel engagement is number two; and then a third potential application is to be used for thrombectomy. The guide extensions can often be advanced deeply into a thrombotic vessel, and then aspiration can be done through the guide catheter itself. The fourth one is for retrieving trapped equipment. This is an example of a patient who had rotablator burr entrapment. The rotablator was cut, and then a guide extension was advanced over the shaft of the rotoblader all the way to the area of entrapment. And after doing that, then the rotor blade or burr could be successfully retrieved. Another application, specifically in CTO interventions, is for facilitating reverse cardiology. Reverse cardiology is when an undergraded balloon is being inflated, and the retrograde wire is used to advance into the proximal to lumen. If one can bring a guide extension distally into the lesion, then the length of occlusion that the retrograde guide wire will need to traverse is much shorter. And this is the guide extension reverse cardiology that can significantly facilitate the retrograde approach. It can also be used—the guide extensions that can also be used for facilitating undergraded subintimal reentry, especially by prohibiting, by reducing the chance of hematoma formation. This is an example of undergraded subintimal crossing. This is a knuckle guide wire, but having in a guide extension can help minimize hematoma that can hinder the entry into the distal true lumen.
And finally, guide extensions can be used to create a snare. This is an example of a so-called Camp snare, courtesy of Dr. Masayeki, in which a guide extension is used together with a small balloon and a guide wire. The balloon is inflated inside the guide extension, pinning the distal edge of the wire, and then by pushing and pulling the wire, the size of the snare can be modified. This is an example of what happens: the wire is being pushed, and the snare size gets bigger; the wire is being pulled, and the snare size becomes smaller. And that can be used. If there are already commercially available snares, there is, however, an alternative of using guide extensions if they're not available, which is to deeply intubate the guide catheter. This is mainly done for the right coronary and much less so for the left main. And this is an example of challenging delivery in a complex right coronary artery lesion. Typically, the deep intubation is done by clockwise rotation and advancement. You can see the guide here is advanced to the proximal and mid segment of the right coronary artery, helping with stent delivery. Eventually, the guide catheter came all the way down almost to the distal RCA, and then this facilitated the post dilation of the stent and achieving a nice final result. Once again, it's almost all the way down to the target lesion.
Here are some tips and tricks when using a guide extension. The first one is to place the push rod under a towel. The reason is that otherwise, there can be entrapment or intertwining between the guide wires and the push rod. So to prevent that, immediately after the guide extension is placed in, it should be placed under a towel so there is no wrapping of the guide wires with the push rod. It can be a very frustrating experience to spend 5-10 minutes to deliver the guide extension to the target lesion and then no balloons or stents will go because there has been wrapping around of the push rod with the guide wires. In terms of delivery, the preferred technique to deliver is called the inch-worming technique, and there is a separate video on this, but very briefly, the way this is done: the guide extension is inserted in the proximal part of the vessel; a small balloon, usually 2 by 12 or 15, is inserted halfway, halfway out of the guide extension, inflated at low atmosphere, six to eight, deflate it, and while it's being deflated, the guide extension is advanced slowly, coming all the way down to the desired location. This is an example of how this looks like: balloon is inflated, deflated, and when it's deflated, the guide extension is advanced, and that helps it go to the desired location. Another way to advance it is the so-called balloon-assisted tracking, very similar to what is done for advancing catheters through tortuous radial arteries. There is a small balloon inflated at the edge of the guide extension, and then that helps deflect the guide extension from areas of tortuosity or helps it go around the stent struts.
A number three tip and trick is to use fluoroscopy when advancing wires through a guide extension. The wire should not be advanced if the guide extension is smaller than the size of the guide catheter because the wire is likely to go around the guide extension, and then when there is a need for trapping, that can be a little difficult because of the length of the cylinder. If there is a lot of tortuosity, the so-called mother-daughter grand daughter technique can be used, which essentially is used in the same patient simultaneously of two guide catheter extensions and eight French and six French. This is how it looks like: this is a complex circumflex lesion; there are two guide extensions, one eight French through which a six French is advanced all the way in the distal circumflex past these two very acute bands, facilitating equipment delivery. And then finally, compatibility is important. This is a chart showing the compatibility of various equipment with various guide catheter extensions; that's important to consider because effectively using a guide extension reduces the internal diameter of the guide catheter by approximately two French, and that makes it harder to deliver equipment.
Guide extensions can also lead to complications. One of them is equipment deformation that can happen both during advancement of equipment through the guide extension and also during withdrawal. This is an example: in the first case, the stent was being advanced into the guide extension and got caught in the proximal collar. This was an older version of the guide liner; this is less likely to occur today with the new version. And this is an example where the stent was difficult to deliver in the coronary, and then on the way back, there was some deformation, and then it caught the edge of the guide extension, and the stent came off the balloon. So whenever there is difficulty advancing balloons or stents through a guide extension, one should stop and use fluoroscopy. This is an example: trying to advance a guide wire; fluoroscopy is important because if one pushes very hard, it is quite likely that the wire will be damaged trying to go through the proximal collar of the guide catheter extension. And this is another example where the wire could not go through the proximal edge of the guide extension, and eventually it was damaged and had to be replaced.
Another complication that can happen any time there is deep engagement is causing dissection. This is an example of a deeply seated guide extension; there is contrast injection, and that causes an aortic coronary dissection tracking backwards. So like everything else, if there is pressure dampening, one should not inject contrast because this is likely to cause dissection. Also, using a guide extension could lead to thrombus formation; that is why the ACT should be closely monitored. There's the possibility of distal migration. This is an example of injecting contrast through a saphenous vein graft, and what we see here is the guide extension essentially take off during injection and migrate distally into the vein graft. The lesson is that you should hold the guide extension during contrast injection. Fracture of the guide extension can occur. This is an example of a case in which there was fracture of a DropLiner, but fortunately, the DropLiner was almost all the way back to the Y connector, and then by removing the Y connector, we were then able to remove the distal segment of the guide extension without having to retrieve it from the body. And finally, like all other aspects of distal engagement of a vessel, one should be very careful advancing guide extensions through previous stents because if it catches the ends of the stent, it can lead to stent deformation, and that is why using the inch-worming technique is very important.
So in summary, the guide extensions have been a revolution for contemporary PCI. They are used very often, most commonly to facilitate delivery, but also, as we discussed, when there is a complication, to facilitate retrieval or sometimes to facilitate angiography. The key thing is to put the push rod under a towel to avoid wrapping around of the guide wires with the push rod of the guide extension. Also, it is important to monitor equipment going in and out because if they catch the collar, equipment damage can occur. Having said that, a very meticulous use of guide extensions advancement in the coronary using the inch-worming technique in a gentle and closely monitored way can allow excellent use of those devices to improve outcomes and minimize the potential safety concerns. Thank you.