Can you tell us about your practice?
I am a vascular surgeon and my surgical fellowship was in Cincinnati at the Good Samaritan Hospital. I have been in Omaha, Nebraska, at Methodist Hospital, since 2012. Here, we like to treat the full breadth and depth of vascular disease, and we have set up our lab accordingly. We recently finished renovations and now have a beautiful hybrid suite with full capabilities. I also travel to Council Bluff, Iowa, which is about 30 minutes away from Omaha; it is essentially one territory. We have labs in both situations. I am an endovascular-first surgeon. I like to consider endovascular options, as it does not burn any bridges to open surgeries. It is the wave of the future and often times a better way to treat patients in the long run.
What are some of the challenges you see in treating critical limb ischemia?
One of the challenges we used to have was getting across a chronic total occlusion (Figure 1). Before we had the Crosser CTO Recanalization System (Bard Peripheral Vascular) (Figure 2), our options were a stiff wire and a straight catheter. Using these tools, we have been taught to push hard through the lesion, invariably causing a subintimal tear, and once you are in a subintimal plane, you have to stent. We have come a long way in vascular technology and endovascular surgery, yet for chronic total occlusions (CTOs), we were still just taking a straight stiff wire and pushing. This is where the Crosser Catheter is fantastic. It enables you to stay within the true lumen; therefore, you are not obligated to stent the patient’s artery as you would if you went subintimal. In fact, in my office today, I saw four separate patients, two from over a year ago, who had experienced chronic total occlusions. In each of these patients, I was able to revascularize their entire superficial femoral artery (SFA). I got through the lesion with the Crosser Catheter, stayed in the true lumen, performed balloon angioplasty, and did not leave a stent behind. The thought process for the treatment of SFA chronic total occlusions used to be that you have to stent, because it is occluded, a lot of disease, and a lot of plaque burden. Over the past four years, the Crosser Catheter has become my go-to device. Total occlusions can be ballooned and remain patent.
The next frontier is finding an optimal treatment of tibial disease. I have found a good treatment algorithm for the bigger arteries, but the tibial arteries are still an area where we do not have much in the way of options. The Crosser Catheter is my go-to device for CTOs in the tibial arteries. The problem is, what do you do after you get through a CTO in the tibials? There is no FDA-approved stent to put in a tibial artery and currently there is no drug-coated balloon, so all we can do is regular balloon angioplasty and hope it works long enough to heal the wound. Unfortunately, when we apply SFA data to the tibials, we know that regular balloon angioplasty does not last very long, so that is why I am waiting for something that can give me longer term patency, although I do not necessarily think of success in terms of patency. In advanced disease, my major goal is to restore flow to the limb in order to promote wound healing. Our patients are not experiencing just a little bit of claudication and a little bit of pain. It is someone with a major wound, and if we do not get it fixed, they could end up losing their limb. The Crosser Catheter has allowed me to quickly and effectively create a channel with laminar blood flow down to the wound.
How does the Crosser CTO Recanalization System work?
The Crosser Catheter ultrasonically vibrates a wire in such a way that when it is put against a hard surface such as a plaque, it can create a channel through the plaque intraluminally. It is similar to the saws that remove casts. When you put it against a softer tissue such as an artery wall, which is more elastic and will give way, it does not have the tendency to bore straight through. It will, however, selectively ablate plaque, which is a hardened structure that does not flex with the vibration of the Crosser Catheter. I think this technology is much better than the other options we as interventionalists have at our disposal.
I start the Crosser Catheter a centimeter or two above the occlusion. That way, I allow the catheter to freely move inside the artery and then engage the midsection of the CTO cap. I gently guide the catheter until I am all the way through the lesion. Intermittently, I will shoot through the sheath to make sure I am going the right direction. Once I am across, I will shoot a small amount of contrast again to make sure I am in the true lumen. That is the best feeling, because then I just take the Usher Support Catheter over the Crosser Catheter. Once through the lesion, then I have access to the distal artery, and I can put through any wire I want, and with that distal wire, I can balloon and, if needed, stent.
If you are about to approach a CTO, how quickly do you advance the catheter and what are some of the things you need to keep in mind?
The traditional approach for most interventionalists or anyone who treats the peripheral vasculature is that you push hard, with a straight stiff wire and straight catheter. You just, for lack of a better word, ram it through the plaque, but you cannot apply that methodology to a Crosser Catheter. The Crosser Catheter is an ultrasonic powered device, it oscillates, and it essentially works its way through the plaque on its own, so you cannot, and should not, use force. You need to move slowly and allow the Crosser Catheter to do the work instead of trying to push it through. So I move very slowly with the Crosser Catheter and simply guide the catheter through the lesion. I find that you just have to have a little patience and you get through the majority of these lesions. The generator has a timer on it, so after you use it for a certain amount of time (5 minutes), you have to hit a reset button and exchange for a new catheter. I rarely ever have to use that reset button. You just have to take your time and let the device do the work. If you think about it, setting aside 5 minutes to cross a CTO with a Crosser Catheter is pretty fast compared to fiddling around with a wire and catheter.
You generally get through the CTO in less than 5 minutes?
Absolutely, but like anything it reflects the type of lesion you have. We all like to think of our successes, but just the other day, I had a chronic total occlusion at the origin of the SFA, all the way through. The only thing that filled was the anterior tibial. It was a very long lesion and it did take a long time. I got through almost all of it until there was just too much resistance and it became difficult to navigate the catheter. So there are those cases that take a long period of time. When it is an 80 to 100 mm lesion, you do go through fairly quickly. It is those lesions that are extremely long, that go from the groin down to the below-knee segment, that twist and turn — those are difficult. But frankly, even then, most of them, I can get across with the Crosser Catheter and treat.
Not too long ago, those patients would go right to surgery, correct?
People would not even try these cases, because they knew that you could not push a stiff wire through all the way down to the tibials in these long CTOs.
What are some of the challenges with a guidewire below the knee in multi-segment CTOs?
By pushing hard with a stiff wire and catheter combination, you may damage the artery and typically create a subintimal dissection. This is not how the artery is intended to be used, so then you are obligated to stent. Since we do not have FDA-approved tibial stents, this can be a significant problem. That is why for below-the-knee interventions in tibial CTOs, the Crosser Catheter is the only device I recommend using. The main benefit of Crosser is that you get through the lesion quickly and you typically stay true lumen, so you are not obligated to stent and you preserve multiple options.
Can you share a case where the Crosser Catheter was helpful?
I have a diabetic Native American patient that I initially met back in 2013. She had a fairly bad diabetic toe ulcer. When I first saw the ulcer, my worry was that she was headed straight for an amputation of at least the toe. I felt we needed to at least attempt revascularization. She had multi-segment stenoses through the SFA, through the origin of the tibials, all the way down to the anterior tibial, and a final stenosis in the dorsalis pedis at the top of the foot (Figure 3). I was able to get the Crosser Catheter through all of it. Afterwards, I was able to track my wire across the channel the Crosser Catheter created through the dorsalis pedis and the stenosis, and finally ballooned all of it. I had to use very small balloons to get all the way down onto the foot, but then I ballooned the entire segment, got all of it open (Figure 4), and salvaged her foot. To this day, she still has a toe and a leg, because we were able to heal that wound. It is now two and a half years out with just Crosser and balloon angioplasty.
Do you anticipate that you would ever need to go back in and redo the procedure?
The question becomes, how do you determine success? Is it patency of the vessel or is it wound healing? For me, it is wound healing. Her foot has never developed an ulcer since. Is it because the artery is open? I do not know. I would never go back simply to revascularize the artery. The only time I would ever go back would be if she developed a wound, and so far, she has not.
How important is angiogenesis in the extremities?
In the leg, the development of collateral vessels is very important. The Crosser Catheter allows us to get through these lesions, stay true lumen, and balloon angioplasty. By staying true lumen, we do not ruin any of the collateral vessels that have developed as we would if we stented a subintimal channel or through showering embolic particles with debulking devices. Maintaining the collaterals will help maintain patency and/or aid in wound care. When debulking devices are used, there is no question that lots of particles are traveling distally and are likely taking out all those vessels that help keep the leg or bypass open.
Do you have any advice for operators who may be interested in trying this device?
One of the best things that you can do when using the Crosser System is to first take some time to explain it to your staff. Explain what you are doing, how you are doing it, and what you are going to do, so they do not get frustrated. They are going to set up the generator, and if they can do it efficiently, it makes the case go easier and quicker. I made the mistake of not taking the time to explain the Crosser System to staff until after I got going with it. However, once we had acceptance, they were ready to go and set it up in no time at all. They can set up the device in 5 minutes or so.
I would also emphasize that you cannot push the Crosser Catheter through the lesion. You have to let it work. If you have any questions of where you are going, just shoot through the sheath. I always put a 6 French Ansel sheath up and over the bifurcation and shoot through that. I try to park the Ansel sheath in the SFA. When I need to do a run to see which direction I am going, if I think I am going the wrong way, I shoot through that sheath. I do not think you should shoot through the Crosser Catheter or through the Usher Support Catheter, because injecting contrast in the occlusion does not really help you as to direction. Generally I just shoot through the sheath to see what reconstitution comes back.
Are you using the GeoAlign Marking System that is on the Crosser Catheter?
Yes. GeoAlign (Figure 5) is simple-to-use, non-radiopaque ruler on the catheter shaft of Bard’s peripheral devices. The GeoAlign markings measure from the distal tip of the catheter and are intended to be referenced outside of the sheath. You can use the markings to give you a quick, easy intravascular measurement between two points, where the lesion begins and ends, and how far your next device needs to travel to reach the same target lesion. You can use less fluoroscopy, and anytime you are fluoroing less, it is beneficial for everybody, including the patient. You do not have to fluoro to see where you are going as your catheter is passing through the sheath in order to make sure your catheter does not end up somewhere else. You can look at the GeoAlign markings outside of the sheath and advance your device. It not only saves time, but it can help to reduce fluoroscopy time and the associated radiation exposure.
Is there any benefit to having the GeoAlign Marking System on multiple products?
Yes, because when you have GeoAlign across different devices (i.e., Ultraverse 035 & Lutonix 035 DCB), it helps you with intravascular length measurements and to align each additional device to where you want to go with less fluoro; you can just watch the markings on the catheter. It means less fluoroscopy time getting to the lesion and a reduction in the associated radiation exposure. Using it across all these lines of products just makes a ton of sense. It all visually looks the same, so you can have confidence in what you are ballooning and where you are delivering your device.
Any other tips or tricks for Crosser Catheter use below the knee?
You have to be careful with use of the Crosser Catheter below the knee, because often people have developed significant collateralization. The most challenging cases I see are chronic total occlusions with a large collateral vessel right at the edge. Catheters will take the path of least resistance. If you do not pay attention, you will be traveling down a collateral and not going through the true lumen of your target lesion. I take more time and more pictures when I am very distal in a tibial artery, because the last thing you want to do is take out a large collateral that has developed. Whether you are successful or not in the intervention, that collateral can help you with limb salvage.
I have had patients where I was unable to get all the way through the lesion, but I have had improvement in wound healing simply from Crosser Catheter use. Sometimes when crossing a tibial lesion, I get through 99% of it and for some reason, I cannot get any further, and I am unable to break through the distal cap. Yet the lumen created from the Crosser Catheter itself seems to be large enough in these rare cases, that when I see these patients back, their wound has healed. I did not balloon angioplasty it and I was not able to get through the entire lesion. In retrospect, wound healing likely occurred because I made a lumen simply by using the Crosser Catheter through that area. I did not take out the collateral vessels and the lumen created from the Crosser Catheter in the tibials permitted revascularization of the wound bed.
What do you envision as the future of the Crosser System?
I use the Crosser Catheter anywhere and everywhere I can in the periphery. In my mind, there is no other competing device that can get through chronic total occlusions like the Crosser Catheter. There has not been a situation yet where I have thought, wow, I should not do that again, it did not work, or, this was not safe. You can apply this technology to really any peripheral CTO.
This article is published with support from Bard Peripheral Vascular.
Disclosure: Dr. John Park reports he was compensated by Bard Peripheral Vascular for his time associated with this article.
Dr. John Park can be contacted at firstname.lastname@example.org.