20 Years of Innovation: How Much Progress Have We Made With Interventional Treatment of Lower Limb Arterial Disease?

“Concepts, techniques, tools, goals of care—all of that’s changed dramatically with regards to catheter-based treatments for lower extremity revascularization over the last 20 years.” So said Peter A. Schneider, Professor of Surgery in the Division of Vascular & Endovascular Surgery at the University of California San Francisco, USA, as he gave his lecture on 2 decades of innovation in the interventional treatment of lower limb arterial disease on Tuesday morning. “It’s an honor to give a talk like this,” he told LINC Today. “I love the structure of this session. Historical perspectives, experience, accumulated evidence and then 20 years of innovation.”

Dr Schneider was a founding member and chief of the Division of Vascular Surgery at Kaiser Permanente in Hawaii in 1994, where he stayed until 2018. “So, 20 years ago, in 2004, I know exactly where I was,” he said. “I certainly can recall that catheter-based lower-extremity revascularization was not reproducible.”

At that time, each case was different and precarious, noted Dr Schneider, and it was quite common to encounter an obstacle during the case, especially if the procedure was on a patient with a challenging lesion morphology or anatomy. Indeed, it wasn’t unusual for that obstacle to cause the case to be unsuccessful.

Lower extremity bypass was still the way that things had traditionally been done for 30 years prior, continued Dr Schneider. “In the back of peoples’ minds I think that was the plan, or at least the backup plan,” he said, noting that most colleagues just had experience of shorter lesions. A lot of experience was quite anecdotal, as well, recalling papers that contained experiences of perhaps one or two cases.

One of the biggest challenges surgeons faced back then was how to deal with occluded arteries without the tools that exist today. “Of course, we had the subintimal wire loop technique that had been in existence for 20 years or more at that time,” he explained. “But it’s not a technique that’s routinely successful. There was no real method of staying in the true lumen.”

That affected goals of care too. “We thought, ‘Let’s just see if this works’. Or, ‘Let’s just see if we can do this too’,” he recalled. “Now we expect it to be successful.”

Most femoral popliteal revascularization was done using .035” systems. “We couldn’t cross a lot of lesions, and we had minimal solutions for calcium,” said Dr Schneider. “We were just in the very first generation of stents and starting to recognize they had a lot of stent fractures.

“It turned out that the femoropopliteal arteries were a lot more hostile to implants than we thought they were. And, due to the mechanical forces, the constant movement, stretching, bending and torsion, any implant that you put in the femoropopliteal segment has to really be specifically designed for it, to avoid device-related complications.” That constant movement and micro-friction between the artery and the implant established a pattern of learning over the next few years, relayed Dr Schneider.

More recently, implant designs, tools and techniques have largely mitigated that. As for crossing occlusions, re-entry devices, crossing devices, CTO (chronic total occlusion) catheters, and CTO wires were developed. “Now, with retrograde access, when you add all of those things up, it’s pretty unusual to not be able to get across a lesion,” said Dr Schneider.

Similarly, the quest to treat calcific lesions is now armed with scoring balloons, specialty balloons, multiple different mechanisms for atherectomy and intravascular lithotripsy. “Back then, we were just proud that we got the lesion open and got a decent immediate result,” Dr Schneider went on. “Of course, in 2004 we had almost no evidence, and the evidence we did have was in quite short lesions.”

To that end, gaining evidence has transformed goals of care. “We really are anticipating longer-term benefits, patency and solutions, mainly through doing an excellent job upfront,” said Dr Schneider, mentioning the advances in crossing, blood vessel preparation, but also multiple devices for drug delivery. “The era of drug delivery is now definitely here, as well.”

Lastly, a tremendous amount of time, effort and energy has been spent developing level-one evidence for multiple devices. There have been multiple investigational device exemption trials, randomized controlled trials, and head-to-head trials with drug-coated balloons, drug-eluting stents, covered and bare-metal stents. The community has developed a way to follow these over the long term too. “We have performance goals and standards that can be assessed with non-invasive evaluations like duplex ultrasound, so that we can actually know and understand how we’re doing,” stressed Dr Schneider.

In other words, there really has been a sea change in the management of femoropopliteal disease, noted Dr Schneider, who commented specifically on the care of these patients day-to-day. “The conversations I have with patients—about what’s realistic, what we can do, what they can look forward to— have completely changed,” he said.

Dr Schneider attributes this progress to the tremendous amount of work put in by his colleagues to improve the field so much in 20 years. “It wasn’t routine back then to have a dedicated team of people working with you every day, getting very efficient, fast and repeatably good results,” he emphasized. In addition, he notes those who developed clinical trials, standards, those within various societies and different specialties, as well as the dedicated players on the industry side.

Societies have evolved enormously too. “We really didn’t communicate with each other, and it’s just a shame to have different groups of eager people very passionately reinventing the wheel quite separately from each other,” he said. “We have a lot of cross pollination now.” Meetings like LINC and VIVA, and the evolution of more recent meetings have contributed to this knowledge base. 

“From the standpoint of catheter-based revascularization, the future is bright,” said Dr Schneider. Procedures are reproducible, sophisticated, and have longer-term results. “I’m not saying that we’ve solved everything—quite the contrary—but we now have drug delivery. We now can look forward to longer-term successes, and we now have a body of evidence to build on.

 “We also have general mutual agreement that we work better together, and for people who are passionate about vascular care, there’s a lot to look forward to here.”