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‘Hope springs eternal’ for dedicated bifurcation stents

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The preference for provisional stenting over dedicated stents for bifurcation coronary lesions still stands, but with further development, dedicated bifurcation stents could still become a viable treatment option, Martin B. Leon, MD, said at TCT 2017.

“Bifurcation coronary lesions are still common and complex bifurcations are still challenging for most clinical operators due to a combination of issues, including the need for more time, skill and equipment costs,” Leon, professor of medicine and director of the Center for Interventional Vascular Therapy at Columbia University Medical Center/NewYork-Presbyterian Hospital and founder of the Cardiovascular Research Foundation, said during a presentation.

Additionally, bifurcation lesions are associated with increased complications, including periprocedural MI, stent thrombosis and restenosis, and suboptimal angiographic outcomes, especially in the side branch ostium, he noted.

During the past 25 years, researchers and operators have sought ways to deal with bifurcation lesions.

“There has been an evolution of procedural strategies for coronary bifurcations, with general agreement that provisional stenting is preferred under many, if not most, circumstances,” Leon said.

Operators now use a variety of new techniques with two stents, proximal optimization technique, jailed wires and more, so the question now is whether there is even a need for a truly dedicated bifurcation stent, he noted.

Data on bifurcation lesions in randomized trials, dating back to NORDIC, BBC One and CACTUS, strongly favor using provisional stenting, as do results from recent meta-analyses, according to Leon.

“There is no question that a more simplistic provisional approach is preferred over a routine two-stent strategy from the standpoint of safety,” he said. “There are more periprocedural MIs, and some studies show more stent thrombosis, while there is very little to be gained from the standpoint of hard endpoints, such as target lesion revascularization or mortality. Several studies have demonstrated slightly different outcomes, but in general, this is what we associate with the aggregate of data on bifurcation stenting.”

Potential of dedicated bifurcation stents

Despite the popularity of provisional stenting, dedicated bifurcation stents have been proposed as a potential alternative under many circumstances, according to Leon. He noted that a multitude of dedicated bifurcation strategies have been developed, all of which involve a variety of different approaches, such as main proximal vessel first, main across side branch to provide side branch access, distal first, side branch first and more.

Nevertheless, of these categories, very few devices are still viable at this point, according to Leon.

“However, hope springs eternal,” he said. “If we had a simplified delivery system that is easy to generalize; has relatively few steps; doesn’t prolong the procedure; protects the side branch or allows permanent side branch access; offers optimal main and side branch scaffolding; limits gaps in support; provides maximal drug coverage, accounts for plaque or carina shift during main branch treatment; and limits multiple layers of stent struts, that would be wonderful.”

Therefore, the goals of a dedicated bifurcation stent, Leon noted, are to reduce target-vessel MI and stent thrombosis, particularly in the side branch, and to reduce TLR and restenosis, also particularly in the side branch.

Leon also reviewed several of the devices designed for use in bifurcation lesions, including the Axxess and Axxess Plus self-expanding bifurcation stents (Biosensors), the BiOSS dedicated bifurcation balloon-expandable stent (Balton), the Nile systems (Minvasys) and the Stentys stent delivery system (Stentys).

He also discussed the Tryton side branch stent (Tryton Medical), a dedicated bare-metal stent that employs a technique that allows significant flexibility. The stent has been studied in a trial involving more than 700 patients — the largest coronary bifurcation randomized trial to date — and the results were mixed, according to Leon.

Overcoming hurdles

Currently, dedicated bifurcation stents, in their current forms, may not yet fit into operators’ armamentarium, Leon noted.

“The case for dedicated bifurcation stents as a routine strategy for all or most coronary bifurcations is not tenable in the modern era of PCI, where one-stent drug-eluting stent provisional strategies continue to dominate,” Leon said.

However, he noted, new techniques, the preference for two-stent strategies among some operators and the results of DKCRUSH-V in left main disease may eventually spur change in the field.

“For distal left main bifurcation and other complex bifurcation lesions — large side branches, some with calcium, angulation and diffuse disease — there could be a viable dedicated bifurcation stent strategy,” Leon said. “But it must be demonstrated that DES technology is available, for the most part, to reduce TLR and restenosis.”

The devices also must be easy to use from an operator standpoint, according to Leon. If new bifurcation strategies are difficult, problematic, fraught with complications and significantly increase expenses, they will not be adopted in clinical practice. Therefore, the economics must be manageable and clinical evidence demonstrating safety and improved outcomes must be generated, he said.

Moreover, more reasonable regulatory pathways to approval of these new dedicated bifurcation stents are necessary to motivate industry to develop these products, Leon said. – by Melissa Foster

Reference:

Chieffo A, et al. Session II. Specialized Stents for Bifurcations. Presented at: TCT Scientific Symposium; Oct. 29-Nov. 2, 2017; Denver.

Disclosures: Leon reports he has received grant support or a research contract from Abbott Vascular, Boston Scientific, Edwards Lifesciences, Medtronic and St. Jude Medical; he has received consultant fees/honoraria or is on the speakers bureau for Abbott Vascular and Boston Scientific; and he has received royalty or intellectual property rights from Cathworks Ltd., Claret Medical, Elixir, GDS, Medinol, Mitralign and Valve MD.