Bioresorbable Scaffolds: Where Do We Go From Here?

NEW ORLEANS, LA—Will they or won’t they? That’s  the question many are asking these days about whether bioresorbable scaffolds (BRS) will evolve from their current state of flux and become commonplace in the interventional cardiology world. In a spirited debate at the Society for Cardiovascular Angiography and Interventions (SCAI) 2017 Scientific Sessions last week, the overall message was one of optimism tinged with caution.

Roxana Mehran, MD (Icahn School of Medicine at Mount Sinai, New York, NY), noted that what started out as a “green light” for the technology quickly changed as troubling real-world data began to emerge.

“We are really in a kind of quandary and a cautionary place right now with so many meta-analyses showing higher scaffold thrombosis—both from the ABSORB II 3-year data, and most recently from the AIDA trial,” Mehran said.

Despite no differences in cardiac death, all-cause death, and patient-oriented cardiovascular events between the Absorb bioresorbable vascular scaffold (BVS) and Xience everolimus-eluting stent (both Abbott Vascular), Mehran said the negative outcomes of target lesion failure and scaffold thrombosis seem to favor the DES as the current standard of care.

“BVS as a first-generation breakthrough technology has important [potential] virtues, but these virtues are yet to be realized. We need longer-term follow-up, and for now, the use has to be selective and cautionary,” she said.

But despite all the “bad data,” Cindy L. Grines, MD (Northwell Health, Northshore University Hospital, Manhasset, NY), said it is important to remember that there is a learning curve with regard to deploying the scaffolds and that early prohibitions were placed on the use of IVUS and high-pressure inflations that were thought to possibly snag or damage the scaffold.

“For years we were implanting these devices in an inappropriate manner,” she said. “The bottom line is the early experience versus the late experience is very different.” Specifically, Grines noted Taiwanese and Korean registries have reported no episodes of scaffold thrombosis when the so-called PSP protocol (preparing the vessel, adequate sizing, and postdilatation) is used.

Overall, Grines said she believes Absorb BVS results can be improved and that it can become the default strategy but, “we just have to stop being lazy and start doing it.” Regarding the very late stent thrombosis cases that have been described to date, she added that none used the PSP technique.

‘Give It Time to Evolve’

Grines added that “this technology is in its infancy, and we really need to keep the results in perspective.” As a reality check, she pointed out that in a 1991 publication, Patrick W. Serruys, MD, PhD (Erasmus Medical Center, Rotterdam, the Netherlands), and colleagues reported a subacute stent thrombosis rate of 24% in their PCI cases.

“Imagine if we got these results and we decided to just abandon this technology. Where would we be today? We have to be more accepting that with early technology you might not have everything figured out and give it time to evolve,” Grines said. “What we are seeing [with BRS] is nothing compared with early metallic stent results.”

We have to be more accepting that with early technology you might not have everything figured out and give it time to evolve. Cindy Grines

Similarly, Ashok Seth, MD (Fortis Heart Institute, New Delhi, India), who spoke with TCTMD following the session, pointed out that BRS were never meant to be a replacement for metallic stents, rather they should be seen as an evolution of interventional technology.

Seth said emerging data bear out the fact that meticulous implantation technique and appropriate use of DAPT, even in the most complex cases, can result in low scaffold thrombosis rates.

He predicted that in the next 2 years newer iterations of BRS, including the MeRes (Meril Life Sciences), will have lower profiles and faster degradation rates. One-year follow-up experience with this device will be presented this week at EuroPCR.

“The bioresorbable technology is here to stay. It is still valuable in a subset of patients and we can’t disregard that,” Seth said. “Who wants a full-metal jacket? We just need to keep working with this technology and [learn] the best way to implant it in the present iteration, which may or may not change as future devices come along. But certainly, I see it growing safer and better.”