No-Stent Strategy for Femoropopliteal Arterial Disease

This edition of Cutting-Edge Perspectives is headed by Nicolas W. Shammas, MD, Midwest Cardiovascular Research Foundation, Davenport, Iowa

Nicolas Shammas, MD, talks with Ehrin J. Armstrong, MD, Professor of Cardiology, University of Colorado, Aurora, Colorado.

The no-stent strategy has gained significant momentum among endovascular specialists. Controlling dissections and leaving no or minimal metal behind in the femoropopliteal artery is an optimal strategy to avoid the long-term consequences of stents in a vessel that is highly mobile and subject to all kind of forces including compression, torsion, kinking, and stretching. Leaving a vessel with the least metal behind and keeping all future therapeutic options open is a commonsense strategy. The path of optimal intervention, by improving vessel compliance, protecting the distal vascular bed, and employing antiproliferative therapy has been adopted by operators who believe in the no-stent strategy. By changing vessel compliance, less barotrauma is needed and dissections are minimized. Recently, the Tack Endovascular System (Intact Vascular) was approved, and significant dissections can now be repaired with minimal metal left behind, thus preserving the natural state of the femoropopliteal artery. 

In this interview with Ehrin Armstrong, MD, we discuss recent technologies that have emerged to change vessel compliance and reduce or repair dissections when treating the superficial femoral artery (SFA) and popliteal artery. 

Do we have to stent the femoropopliteal artery? Can optimal intervention be achieved without stents? 

Stents have an important role in the treatment of femoropopliteal disease, but they are by no means necessary in every case. The major use of stents is to treat dissection or recoil of the femoropopliteal artery after vessel preparation. For these reasons, optimizing vessel preparation can minimize the need for stent implantation. In my practice, I frequently perform atherectomy to debulk the target lesion and minimize recoil after balloon angioplasty. I also think that specialty balloons, such as the AngioSculpt (Phillips) and Chocolate balloon (Medtronic) can help optimize the results of balloon angioplasty and therefore minimize the need for subsequent stent implantation.

Do you think dissections influence patients’ outcomes? 

Dissections definitely influence the outcomes of endovascular interventions. We have recent, robust publications demonstrating that essentially any dissection is associated with an increased risk of restenosis after balloon angioplasty. There is also an important relationship between lesion length and the impact of dissections on patency – in longer lesions, even minimal (eg, Type A/B) dissections likely impact outcomes. Finally, recent studies have also shown that, compared to core laboratory analysis, operators tend to underestimate dissection severity after balloon angioplasty. As operators, I think we need to re-train our eyes to look closely for dissections. This includes performing imaging in multiple views and using adjunctive imaging such as intravascular ultrasound (IVUS).

Given that angiography does not identify dissections adequately, do you think there is a role for IVUS to become a routine imaging modality when treating the SFA or the popliteal artery?

There is no doubt that intravascular imaging is more sensitive than angiography in identifying dissections. Recent studies have shown that IVUS can identify 5 to 7 times more dissections than are visualized on angiography. IVUS also provides important information on the depth of the dissection, and whether there is an intramural hematoma. The challenge with IVUS is deciding which dissections to treat, and for those reasons, we need more data regarding the role of IVUS guidance in femoropopliteal interventions. 

What are some methods to control dissections?

Atherectomy and specialty balloons are both excellent approaches to optimizing balloon angioplasty and controlling dissections. Multiple studies have demonstrated that plaque modification and debulking can help minimize the atmospheric pressures necessary to create luminal gain, and also minimize the frequency and severity of dissections. Scoring and focal force balloons can also cut into the plaque and thereby control the dissections that occur with any balloon angioplasty.

Intravascular lithotripsy is a new approach for controlling dissections, especially in severely calcified lesions. By creating ultrasonic waves, lithotripsy can effectively disrupt the sheets of calcium within plaque, and therefore improve the results of balloon angioplasty by minimizing both recoil and dissection, which are both more common in lesions with severe calcification. 

When dissections occur, what is your algorithm now to repair them and when to repair them? 

If a dissection occurs, prolonged balloon angioplasty can sometimes help resolve a dissection. Stents are a proven therapy for dissections, and I think stents are especially useful when there is concomitant severe recoil, or when the dissection extends across a long length (eg, > 200 mm). The Tack Endovascular System is purpose-built for treatment of dissections and has some unique advantages compared to stents. Because the implants are so short (6 mm), the amount of metal implanted is approximately 70% less than a stent used to treat a similar length lesion. Because the device comes pre-loaded with 6 tacks, it is also possible to place each tack in specific areas of dissection, rather than just covering the entire lesion length.

Can you share an illustrative case?

I recently treated a patient with nonhealing ulceration of his right great toe. He had a severely calcified lesion in his popliteal artery, as demonstrated in Figure 1. Due to the calcification, I performed intravascular lithotripsy with a 5.5 mm × 60 mm balloon (Figure 2). After balloon inflation, the lesion had a residual type C dissection (Figure 3). Therefore, I placed 3 tack devices across the area of dissection (Figure 4). Final angiography demonstrated no residual dissection or recoil (Figure 5). This case demonstrates the value of optimal vessel preparation with devices such as intravascular lithotripsy, and then tack implantation to minimize the amount of nitinol implant necessary. 

Disclosure: Dr Nicolas Shammas receives educational and research grants from Intact Vascular, Phillips, Boston Scientific, VentureMed Group and Bard. 

Dr Ehrin Armstrong reports consulting for Abbott Vascular, Boston Scientific, Cardiovascular Systems, Gore, Intact Vascular, Medtronic, and Philips.

Address for correspondence: Dr Ehrin Armstrong can be contacted at ehrin.armstrong@gmail.com.

Dr Nicolas Shammas can be contacted at shammas@mchsi.com.