Guidewires - Expert Round Table

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DOI
https://doi.org/10.15420/usc.2008.5.1.34

Successful percutaneous coronary intervention (PCI) starts with a coronary guidewire that possesses specific characteristics designed to support advancement through various coronary vasculature anatomies. These wires can be grouped into four major categories based on their construction: stainless steel, hybrid, plastic, and niche. Steel guidewires can be further subdivided based on performance attributes: workhorse wires, which are designed to provide support, torque, and lubricity for passage through various complex anatomies, as well as to allow delivery of stents, catheters, balloons, and other devices; and chronic total occlusion (CTO) wires, which are designed for tackling the complex lesion morphology often associated with CTOs.

Today’s discussion will address the workhorse wire group. Workhorse wires account for about 70% of all coronary wires used; however, there have been precious few technological advances in workhorse wires over the past decade—arguably until now, with the development of the truly hybrid (stainless steel/nitinol) Runthrough coronary wire from Terumo. This new hybrid wire was utilized in a number of live cases at Transcatheter Cardiovascular Therapeutics (TCT) and Scripps courses in 2007, and is challenging the market domination of Abbott Vascular’s BMW and Prowater stainless steel wires. For the purpose of today’s discussion, the focus will be on the thoughts of our expert panel regarding this new hybrid wire: how it compares with what has been traditionally used in their laboratories, and whether they think it will help to increase procedural efficiency.

For background purposes, can you start by revealing how many different types of workhorse guidewire you use in general and what their various merits are?
Moses

In terms of workhorse wires I really use just two: the BMW and the Runthrough. BMW has been a stalwart over the years. It is very versatile but it has its limitations: given the standards of steerability now, it is not quite up to, say, the Runthrough or the Asahi family of wires. It is not as steerable as the most contemporary wires. It also had a stickiness problem, but that seems to be a little better with the new coating, although the transition is less than ideal. The Runthrough is a bit more steerable and also appears to be just a little more slippery going through tight lesions. The BMW has the advantage of being able to prolapse a little better, so I tend to use it in vessels where I want a little distal prolapse to move it down the vessel quickly, for example in a tortuous left anterior descending (LAD) artery. I tend to use the Runthrough when I need more accuracy and steering or better transition on the wire, for example around entry bends into the lesion.

Sharma (excluding wires for CTOs)

For the last eight to 10 years I have used the BMW in 75–80% of cases; for the remaining cases I have used other wires, such as BSC’s Luge/Choice Intermediate (1998–2005) and Abbott’s Fielder wire (for the last three years). The advantage of the BMW is its atraumatic tip, its ability to retain tip configuration, and the fact that it provides adequate support in the majority of run-of-the mill cases. Therefore, I was very happy with my guidewire selection and always considered it as the most important part of interventional procedures, as well as when teaching interventional fellows (I teach seven every year). However, five months ago—after initial positive feedback from some of my interventional colleagues—I began using the Runthrough-NS wire by Terumo, initially with great skepticism. Within weeks, Runthrough-NS became my favorite wire and I now use it in 60–70% of cases.

Goldberg

For years, my workhorse guidewire of choice was the BMW, which I used in the vast majority of cases. However, the BMW is not useful in certain scenarios, such as extremely tortuous vessels, angulated take-offs of vessels, CTOs, and even some acute occlusions. There have been niche applications of certain other wires, and for total occlusions people have used the hydrophilic family of wires such as PT Graphics or a Choice PT (Boston Scientific) to try to get across. The disadvantage of those wires, however, is that the hydrophilic tip may lead you into a subintimal passage, so people have gone on to things like the Asahi family of total occlusion wires and Miracle Brothers wires for that application. Recently, I have been using the Terumo, and I have to say it has now become my wire of choice, replacing the BMW as my first-line wire.

Rutherford

I use only one or two workhorse wires, and in recent years we have used the Asahi Soft, which is actually a stainless steel wire. Asahi has designed a family of wires that contains both workhorse wires and specialty wires for CTOs. One characteristic of the Soft is that it steers very easily, almost with a one-to-one response from its proximal end transmitted to the tip. In addition, the tip of the wire can be readily shaped for different types of anatomy, for example when entering a bifurcated lesion. Finally, the tip of the wire is very soft and atraumatic, so it does not cause any damage to the endothelium in its transmission down the coronary artery. The BMW is another wire that we have used a great deal as a workhorse wire. The shaft is slightly stiffer than the Asahi Soft, so it supports the movement of stents around angles and bends a little better. I would say, though, that 90% of the time I use the Asahi wire.

Parashara

I regularly use the Runthrough. It is more steerable, so it can go through difficult, angled lesions.

Do you have a particular favorite guidewire? If so, what qualities does it have that you appreciate? Does your favorite guidewire change often or do you use the same one out of habit? Do you try out new types of workhorse wire as they become available?
Moses

I do not have an overall favourite. I have my general workhorse, and for specific anatomical situations I have wires that fill the niches. For CTOs I tend to favor the Asahi Confianza Pro these days, even more so than the Miracle Brothers series. For very tight subtotal occlusions, I tend to go with a hydrophilic wire, for example the Asahi Fielder wires. For something that has an extreme angulation or that will be going through a stent structure where ordinary workhorses fail, I tend to go with a Prowater. These are niche wires—otherwise I tend to use the BMW and the Runthrough.

I also try every new one that is developed. Frankly, the only one that has come along to challenge the BMW has been the Runthrough. The others just have not met my satisfaction. As the Runthrough had been widely used in Japan, its reputation preceded it and I was skeptical. However, it is the first one that has grabbed my attention.

Sharma

As I mentioned earlier, I was very happy with my guidewire choices and hence did not want to change, but the interventional field is such that you keep changing because of the emergence of new products or improvements to old products. I am glad that I tried the Runthrough wire and have been very satisfied with it. The qualities you need in your favorite guidewire are easy torqueability, tip retention, moderate support in most cases, ability for re-use in different vessels, and not causing wire perforation. I quickly noticed all of these qualities in the Runthrough wire, especially the ability to get to angulated lesions by having one-to-one torque and steerability.

Goldberg

These days I prefer the Terumo Runthrough for standard routine cases. I like its excellent tactile feel and ability to engage tortuous vessels and angulated take-offs. Overall, the tactile feedback, torqueability, and ability to cross into angulated segments makes it a very nice wire to work with. The nitinol tip also allows for a longer retention of the tip shape. I think it is a combination of the nitinol core with the stainless steel core that leads to better torque/steerability. The outer coating of the tip is hydrophobic, which gives me a feeling of having a lesser chance of subliminal passage. Overall, the wire works quite nicely.

Rutherford

I prefer the Asahi wire myself. As I mentioned earlier, this is due to the easy steering and wire tip flexibility, as well as its minimally damaging aspect. As for changing the workhorse wire, we change it very infrequently. For example, for almost a decade we used a wire that was an Advanced Cardiovascular Systems (ACS) wire, a high-torque floppy wire that came out of California. Since then we have used the Asahi Soft. Now we also have the Runthrough wire, which we are using fairly often. The tip of the Runthrough wire is extremely flexible, which makes it it a very safe wire that is very good for passage through the bends and angles you often have to deal with in the coronary circulation. It also steers very nicely, almost on a one-to-one basis like the Asahi Soft. If there is an advantage of the Runthrough wire over the Asahi Soft, it is probably that the tip of the wire is so very nice and floppy and flexible that it will do virtually no damage as it transits through the coronary tree.

Goldberg

I think interventional cardiologists are often creatures of habit who get used to a product, understand its advantages and limitations, and get comfortable with a certain type of wire. The wire is critical because it is the first step in obtaining really good control of the vessel. Nevertheless, I have not been that excited about guidewires. It is a stable market and most of our interest is in other areas; sometimes you take one of the most important pieces of the procedure for granted. However, I do think, for example, that the Miracle Brothers wires have been a real advance: they are my wires of choice for CTOs. Similarly, this new Terumo adds to the comfort that I have with difficult cases.

Parashara

I have been very pleased and had successful outcomes using the Runthrough. It is a very good, durable wire, with a shape that stays the way you want it. It is stiff enough to get the stent or balloon down to the lesion site and is also very steerable. It has led me to change my workhorse guidewire from BMW to Runthrough.

Rutherford

We do try new types. This laboratory performs a lot of stent trials and guidewire trials, so the companies bring us wires to test. It is amazing how a subtle change can make such a big difference in wire passage. Over the years there have only been a few wires—such as the Asahi Soft or Runthrough—that have come into my hands and displaced the wire I was using as my first choice. Constant use influences my decisions about changing my usual choice of wire: every day, I see different types of anatomy in different cases, so if you find that one wire consistently behaves well, consistently steers well, and gets where you want to go quickly and easily, you will tend to switch to that wire. The Runthrough is certainly equivalent to, and possibly better than, the Asahi Soft in that the tip is so flexible and atraumatic, but I am just not yet certain whether it steers quite as well. I don’t think I have used it quite enough yet.

Within one procedure involving multiple lesions down an artery, how many guidewires do you typically use? If it is more than one, why is that necessary? Have you seen any impact on the number used with this new hybrid wire?
Sharma

On average I use 2.1 guidewires per case, with 1.4 multivessel and 2.2 lesions per PCI. The BMW wire could be used in multiple lesions and multivessels by preserving its tip in about two-thirds of cases. In about 20% of cases, I use two guidewires (buddy wires) to provide extra support for delivery of stents in angulated, calcified, and tortuous lesions. It was a pleasant surprise when I started using the Runthrough wire and found I was able to use it in multiple vessels and multiple lesions as the tip retained its shape in the majority of cases. Moreover, a dramatic change has occurred in my practice in terms of a significant decline in the use of buddy wires, as the Runthrough wire provides great support. I have analyzed the data from our interventional database and the buddy wire technique is now required in fewer than 10% of cases—a dramatic 50% decrease in the use of a extra wire for support. Of course, in some tough cases I still need a buddy wire and in these situations Grandslam by Abbott is my first choice. In some angulated cases (such as diagonal and obtuse marginal) where Runthrough may not be effective, the extra support provided by Whisper (Abbott) or sometimes the Venture device (St Jude’s Medical) helps me to cross the lesion.

Moses

If they are not CTOs, I tend to try to use one wire. Assuming the occlusion does not have any of the aforementioned specific anatomical sub-sets, the most important thing is for the tip not to lose its shape. That is why the durability of the tip of BMW and Runthrough has made them both versatile wires. I like to be able to re-shape the tip at will to cope with a different radius of curvature—say moving from one vessel to another—and it is nice to be able to re-shape it and minimize the number of wires per case.

Goldberg

It depends on the situation with each vessel. One wire may be appropriate for one lesion and one vessel, but it may not be appropriate for another vessel. However, in general I think for a routine multilesion, multivessel PCI, I would use one wire. The wires mentioned earlier—the BMW, Asahi, Terumo, and Miracle Brothers wires—are all suitable for these routine PCIs. There may be a slight advantage to the Terumo, though, because of the nitinol tip, which may hold its curve a little bit longer.

Rutherford

Many cases have multiple lesions down the artery, and you would expect a single wire to be able to pass all of those lesions, and also for the wire to be able to support the passage of a balloon through those lesions. If there is a branching anatomy where the wire has to be passed into one branch and not another, that is where steerability and torqueability become very important. Over the years, we have found that the Asahi Soft turns almost on a one-to-one basis, so it requires very little manipulation at the proximal end of the wire. Having said that, the torqueability of the Runthrough is very close, but I have not used as many Runthrough wires as I have Asahi Soft, so cannot say for certain.

Sometimes one wire has to be completely withdrawn and a fresh one used, for example in tortuous anatomy if the first wire could not support the movement of balloons and stents over the wire. Under these circumstances you want different characteristics in your wire, such as a stiffer shaft to allow the passage of balloons and stents, so you might change from a very soft wire like the Asahi to something like a BMW that is a balanced middleweight wire, so that the wire shaft has more body.

One other thing is that the tip of the guidewire will occasionally suffer when going through a total occlusion. The tip might strike a piece of calcium or a large plaque and will actually bend back on itself. This does not really affect the Runthrough wire because the tip is so soft and flexible that it will not cause any damage. We generally do not like to pass a wire down an artery with its tip folded over, but this can be done quite safely and is perhaps one of the big advantages of the Runthrough.

Parashara

Sometimes a lesion is very difficult to cross and requires a change of wire. This used to happen 5–10% of the time. Furthermore, having crossed one lesion may affect the tip of the guidewire, which may also require a change of wire. However, when I use Runthrough I am able to get it across the lesion 99–100% of the time and rarely have to use a second wire. It is therefore cost-efficient. It costs around the same as the BMW and Prowater wires, but instead of using two wires for two vessels, I use one. So on the whole we save around 20–25% of overall wire cost.

With two-vessel angioplasty I always look to see if I can use the same wire for the next lesion—can it cross into the side branch after I put in a stent? Runthrough is one of the wires that I use to get access to the side branches.

What are the three most important attributes you require from your current workhorse wire (torque, trackability, support, tip stiffness, durability, etc.)? Does this new hybrid wire possess all of these attributes? How is it differentiated?
Moses

There are several aspects: you want versatility; you want one that steers well but has a durable tip for a workhorse; you want it to have enough body for traction of your devices; and you want a decent transition that is versatile enough to go through different angulations.

Goldberg

I think torqueability is the most important attribute, followed by safety of passage, the tip, and tactile feedback. I think the Terumo has all of these attributes.

Rutherford

I agree that the two most important features are first, torquability, and second, having a soft, flexible, atraumatic tip to the wire—but for me, number three is to provide enough support to allow free passage of stents and balloons. Although the Runthrough scores very highly on the first two attributes, I think the body of the Runthrough wire is not always stiff enough to support the passage of balloons and stents in complex or calcified angulated anatomies.

Parashara

First, a guidewire should be really steerable in order to get to difficult lesions. Second, it needs to have good strength to get equipment to the lesions. Third, it should be easily shaped to get around the angles and to get to the lesion you want.

Sharma

In my opinion, torqueability followed by trackability and then support are the three most important attributes of a good workhorse wire. In addition, the wire should be safe and not cause perforation. I was able to find all of these attributes in the Runthrough wire. I have used this wire over 500 times now and am very pleased with the performance and the lack of perforation due to the hydrophobic tip.

Can you summarize your thoughts about the overall importance of using the appropriate workhorse guidewire to a successful procedural and patient outcome?
Rutherford

I think, number one, it is mandatory that you can approach a patient with a very user-friendly wire that will allow passage of the wire quickly and easily with no damage to the endothelium or to the artery—that is absolutely critical. Guidewires are often the unsung heroes of angioplasty, and there has probably been a lot less time spent on developing wires in the past few years than there could have been.

We perform a lot of CTOs here at St Luke’s, and we are always looking for improvements: wires with specialty tips that are either hydrophilic or non-hydrophilic, and either tapered or non-tapered, so that we have a little more advantage and a little more steerability in getting through these completely occluded vessels.

Sharma

Guidewire selection and advancement remains an integral part of interventional procedure and teaching to the fellows. Therefore, this part of the PCI procedure has to be consistent and reliable with no surprises. Making the right tip bend and selecting the appropriate guidewire are very important for the successful performance of an interventional procedure, especially if the vessel is diffusely diseased.

Goldberg

Well, every procedure has to start with certain basics. You need good guide catheter support and a wire that you feel can confidently cross the lesion. If you are struggling because the wire is non-torqueable, it loses its tip shape, or you cannot really get a good feeling of it for control, obviously the procedure will be more difficult. Also, as you are entering arteries that come off at sharp angulations, you want to be able to shape the tip appropriately and steer the wire in such a way that you minimize the time spent in passage and in lesion in these challenging cases. You also want to be able to slide your balloons and stents over the wire in such a way that there is smooth passage. You do not want the wire to become an impediment to crossing a lesion with your dilatation and stent equipment.

These attributes are the basis of the guidewire, and are extremely important—once you have control of the vessel with the wire, the rest of the case usually goes pretty well.

Moses

Each individual operator obviously has to be comfortable with the handling characteristics of his or her guidewire. Devices have to match the operator, and people have different styles, so one size does not fit all. I am not sure there is a perfect workhorse just yet. We are getting better: the Runthrough has helped in moving in that direction, but the technology can still advance further.

Parashara

It is important to pick a wire you feel comfortable with and that is also appropriate for the difficulty of the procedure. It needs to be steerable, and once it gets through it needs enough strength to deliver the equipment to the lesion area. Those are the main factors.