New Technology

Advances in Guidewire Technology

Cath Lab Digest talks with Mark Dorogy, MD* and David Rizik, MD**
Cath Lab Digest talks with Mark Dorogy, MD* and David Rizik, MD**
What characteristics do you find important in regard to guidewire construction? Even with the many changes in angioplasty, the one thing that still hasn’t changed in terms of guidewire characteristics is the ability to torque and maneuver your wire through the most tortuous lesions. For straightforward, sort of slam-dunk lesions, you can really use just about any wire, but I still look at torquability through the more circuitous vessels as one of my preferred characteristics on the wire. I was very pleased after using some of the AVD Asahi wires. Specifically we’ve used the Prowater wire most recently in our group. I consider it one of our workhorse wires and it’s done a really fine job for us. What is it about the Prowater that you particularly like? You can approach a variety of different lesions with the Prowater wire. It’s very maneuverable through tortuous vessels; that’s specifically what I like about this wire. It seems not to be a very harsh wire in the coronary milieu. We’ve had less dissections, pseudo dissections and other complications with the wire. We’ve been able to do a lot of exchanges with balloons, stents, bulky devices, etc., over the Prowater. It’s been a very, very highly useful wire. It’s got a lot of utility to it. Would you find that you use it in your more challenging cases? It depends on how you define challenging. Challenging can be several different scenarios. One type of scenario can be a tortuous vessel, or side branch vessel that requires a lot of manueverability and torquability of the wire. I find that the Prowater wire is very well suited for a wide variety of those types of situations. Another challenging coronary lesion would be a chronic total occlusion (CTO). I find CTOs to be the most challenging. We’ve had a lot of success with what’s called the Confianza wire. Basically, by using a Confianza wire with a 2.5 or 3 mm over-the-wire balloon system for backup support, we have been successful in about 60-70% of our chronic total occlusions. How frequently do you see CTOs in your practice? In most practices, generally you see CTOs in about 5-10% of cardiac catheterizations. Some of them are well-collateralized, and it’s relatively unimportant to try and cross these, but for those vessels in which it is important to at least attempt a chronic total occlusion, operators have had great difficulty. It is one of the Achille’s heels of percutaneous intervention. Is there a case example that comes to mind? We recently had a patient come to Scottsdale from Florida. He had two previous attempted interventions on his chronic total occlusion of the RCA. One of the attempted interventions involved a device specifically geared toward CTOs. In this case, we specifically defined the coronary anatomy. It was not a particularly well-collateralized vessel, which explained why he was having so much chest pain. There was a CTO in the mid portion of the RCA. Using a Confianza wire with a 2.5 mm balloon for backup support, we were able to sort of poke at the lesion and finally negotiate the lesion and get the wire distally. We then placed the balloon out distally, replaced for a 300 length wire and then successfully performed angioplasty and stenting of the vessel. How long have you been using the AVD Asahi wires? Probably for the last 6 months. It was an interesting transition. I had used a fair amount of Guidant wires prior to this and a fair amount of Boston Scientific wires, but made a real conversion on the majority of my cases to Asahi wires. Do you see anything that needs to be improved in guidewires in general? Guidewire science has sort of lagged behind advances in the field like drug-eluting stents. Especially for CTOs, we need to figure out new devices which incorporate wire technology, in which we can take on tougher chronic total occlusions those which don’t open by traditional means, where we know that we’re keeping the wire in the center of the lumen. But that goes more toward adjunctive technologies. Where wires could play the greatest role is really in chronic total occlusions, which remains, as I noted, our Achilles heel. I think we have to do a lot better work in developing wire-based mechanisms for crossing CTOs. Do you have any advice for other operators who may be considering these guidewires? I would say give them a try, and compare them side-by-side with the other wires out there. You will be very pleased with the broad group of cases for which you can use these wires, specifically the Prowater wires. In the cath lab, we are entering almost an unprecedented time of cost containment, because drug-eluting stents are so expensive and other adjunctive modalities are so expensive. Given the fact that these wires have such a great and broad utility to them you can use these wires for multiple lesions, multiple different lesions during the same case, multiple arteries during the same case they seem to hold their form when you put your bend on the wire. They are really truly a workhorse wire, especially the Prowater. You can use one wire to approach multiple lesions in the same case; therefore, you don’t have to make a lot of exchanges and change out a lot of wires. Next... Dr. Mark Dorogy We were recently working on a complex LAD-diagonal stenosis… In regard to guide wire construction, what characteristics or features do you find most important? In general, I like a wire that is torquable, and provides good support. Clearly there are some cases that are more challenging than others, i.e. greater tortuousity, lesion morphology, chronic total occlusions (CTOs), etc. What do you look for in a wire for these type of cases? Support is paramount if you are working in a tortuous or calcified vessel, but these are also situations where a steerable, trackable, softer-tipped wire is also needed. You need to get through the tortuosity but then have the stiffness of the wire to pass balloons and stents. What was it about your experience with the AVD Asahi wires that you found unique? I found that it was easier to manipulate these wires. I didn’t have to spend as much time crossing difficult stenoses. The wires do have a gentle, steerable tip, and depending on the wire that’s used, sufficent support to advance your equipment over. For example, we were recently working on a complex LAD-diagonal stenosis. It was a near-total occlusion, fairly angulated, and with a moderate amount of calcium. I wasn’t able to advance another manufacturer’s hydrophilic wire across the lesion, so I tried a Prowater, which is one of the AVD Asahi hydrophilic wires. I was able to get the tip into the lesion, and then with minor manipulations, the wire crossed and was advanced into the distal LAD. The Prowater is a hybrid wire that has a hydrophobic tip and hydrophilic working length, so the tip is very steerable, allowing you to maintain control of the wire. I then completed the case without further difficulties. The Prowater made the lesion less challenging; I don’t think I would have had that kind of success with another wire. How long have you been using the Asahi guidewires? Three to four months. What did you use previously? The Allstar wire was my workhorse. I would use the Choice PT Extra Support wire on occasion to cross total occlusions. Do you have a particular guidewire that you rely on? Yes, the Prowater has become my workhorse wire. It has a hydrophilic coating that I like, but the coating stops a few centimeters from the wire tip, lessening the chance of wire perforation. If I have an occlusion I’m trying to cross, I’ll try one of the Miraclebros or Confianza wires. If I want something stiffer I’ll use a Grand Slam. Do you see any future improvements with guidewires? Chronic occlusion wires still need some work, though the Asahi specialty wires have been a welcome addition. Do you have any advice for people who may be considering using the AVD Asahi wires?? I think it’s worth trying them. Find the AVD Asahi wire that is similar to the one you’re accustomed to using now and start with it. Next time you have a lesion that you can’t cross, try one of their specialty wires. I think most interventionalists will find some advantage to the AVD Asahi wires by virtue of their design differences. I think they are designed a little better than the current standards. Discovering their unique design is what convinced me to try them in the first place. Once I tried them, I could clearly see the advantages of using the AVD Asahi wires.