More advances in femoropopliteal intervention technology on horizon

CHICAGO — Endovascular technologies for treatment of patients with femoropopliteal lesions have advanced rapidly in recent years, but more innovation is on the way, an expert said at AMP: The Amputation Prevention Symposium.

“Femoropopliteal intervention techniques have reached the same efficacy level as coronary interventions — just 20 years delayed,” Thomas Zeller, MD, head physician in the department of angiology, Universitäts Herzzentrum, Bad Krozingen, Germany, said during a presentation. “Plaque modulation strategies will further improve the efficacy of drug-eluting technologies.”

Zeller presented five categories of new technologies: dedicated or biomimetic stents, drug-eluting stents, next-generation drug-coated balloons, sirolimus-eluting DCBs and lithoplasty.

Dedicated or biomimetic stents such as Supera (Abbott Vascular) and Tigris (W.L. Gore & Associates) are designed to “mimic the biology of the native artery,” he said.

Thomas Zeller

Another such stent, BioMimics 3D (Veryan Medical), has a helical centerline design allowing it to curve in the same way that arteries do, putting less stress on the arteries and enabling the stent to “accept much more external force than a regular stent,” Zeller said.

In a trial of the BioMimics stent vs. a straight stent (LifeStent, Bard Peripheral Vascular), the BioMimics group had better primary patency at 2 years (72% vs. 55%; log-rank P = .0497) and in a landmark analysis, more freedom from target lesion revascularization at 2 years (91% vs. 76%; log-rank P = .0263). “At 2 years, the curves did separate, a signal of the change in vessel conformability that might be protective from restenosis,” Zeller said.

The Eluvia (Boston Scientific) DES, which has two layers, one for elution and one to adhere the elution layer to the stent, is an example of the latest innovations in DES, according to Zeller. The MAJESTIC trial was encouraging for the technology, which showed 96.1% primary patency at 1 year.

All available DCBs in the United States and Europe use paclitaxel, and an example of the next generation of those devices is the Chocolate Touch (QT Vascular), which is designed to deliver paclitaxel predictably and has a larger contact surface area than plain balloons, Zeller said.

In a first-in-human study, 6-month patency was 88.9% in the intention-to-treat population and 90% in the per-protocol population. However, sirolimus may be better than paclitaxel as an agent with DCBs because it has a higher margin of safety and a wider therapeutic range, he said. The challenge, however, is that with sirolimus, tissue absorption is slower and tissue retention is shorter than with paclitaxel.

“It is difficult to get sirolimus to enter into the arterial tissue within 30 to 180 seconds of balloon dilatation, hence some ‘instant glue’ is required to transfer the drug from the balloon to the tissue efficiently,” Zeller said. “Sirolimus must be continuously delivered over time, so some form of time release mechanism must be employed to maintain therapeutic levels.”

The design of a new sirolimus-coated balloon, Selution (Med Alliance), employs micro-reservoirs made out of a biodegradable polymer that intermix with the sirolimus for a controlled and sustained drug release, and a cell-adherence technology that protects the micro-reservoirs during the procedure.

In an in vitro test, 39% of the drug was transferred to the vessel within 1 hour vs. 5% or less for the two FDA-approved paclitaxel DCBs, Lutonix (Bard) and IN.PACT Admiral (Medtronic), Zeller said. A first-in-human study to demonstrate noninferiority to the two FDA-approved devices will be launched soon.

A novel lithoplasty balloon-based technology (Lithoplasty System, Shockwave Medical) “emits energy in ... shockwaves to break calcium into small pieces,” he said.

In an angiographic study, acute lumen gain was 3 mm, more than what has been seen in trials of atherectomy in calcified lesions.

“It will be very interesting to see the outcomes of the ongoing studies of the new technologies,” Zeller said. – by Erik Swain

Reference:

Zeller T. SFA and popliteal artery treatment options in 2016: Where do we stand and what should we do? Presented at: AMP: The Amputation Prevention Symposium; Aug. 10-13, 2016; Chicago.

Disclosure: Zeller reports financial ties with 480 Biomedical, Abbott Vascular, Bard Peripheral Vascular, Biotronik, Boston Scientific, Cook Medical, Cordis, Medtronic, Philips, Spectranetics, Straub Medical, TriReme, Veryan, VIVA Physicians and W.L. Gore & Associates.