Shelley Wood

November 01, 2013

SAN FRANCISCO, CA — Two studies of drug-eluting balloons (DEB) were met with cautious optimism—and some caveats—here at TCT 2013 . One was a trial mandated by the FDA for a device seeking approval for the treatment of femoropopliteal lesions, the other a study using a DEB to treat restenotic bare-metal stents.

The first, LEVANT 2 , was designed to look at 12-month outcomes in 476 patients with stenotic femoropopliteal arteries randomized 2:1 to either a drug-eluting balloon (Lutonix, Bard) or standard balloon angioplasty; earlier this month, the company announced top-line results, saying the trial had met its primary end point. But when Dr Kenneth Rosenfield (Massachusetts General Hospital, Boston, MA) presented the results at the TCT meeting this week, he gave only the six-month results, leading some to question why he didn't provide at least a glimpse at the 12-month findings.

Dr Kenneth Rosenfield

At six months, Rosenfield noted, there were no safety differences between groups (defined as amputation, reintervention, or index-limb–related death). For the two efficacy end points, however, results were mixed. While freedom from restenosis was significantly more common in the DEB group, rates of target lesion revascularization (TLR) were identical in the two groups. Binary restenosis, a secondary end point, was halved in the DEB group compared with the standard angioplasty group (17% vs 34%, p<0.001).

Those findings left experts discussing the findings uncertain as to how to interpret the results. Dr Bernard Gersh (Mayo Clinic, Rochester, MN) called angiographic restenosis the "less subjective" end point but acknowledged he'd want to see a bigger trial if TLR were the only end point.

Likewise, Dr James Hermiller (St Vincent's Heart Center, Indianapolis, IN) agreed that while the restenosis numbers appear to point to better patency, "we'd want to know if that turns into a clinical benefit as well."

RIBS V: In-Stent Restenosis

Dr Fernando Alfonso

The second DEB trial featured at TCT was RIBS V , a 25-center Spanish study that randomized 189 patients with bare-metal-stent restenosis to DEB treatment or treatment with the Xience Prime (Abbott) everolimus-eluting stent. Dr Fernando Alfonso (Hospital Universitario "La Princesa", Madrid, Spain) was the primary investigator and presenter.

As Alfonso noted, many interventionalists had predicted that in-stent restenosis would become "a thing of the past" in the drug-eluting-stent (DES) era; that has proved not to be the case. In fact, many operators reverted back to bare-metal stents over concerns about stent thrombosis or protracted need for dual antiplatelet therapy with DES.

In RIBS V at nine months, in-segment mean luminal diameter (MLD), the primary study end point, was 2.36 mm in the stent group and 2.01 mm in the DEB group (p<0.0001), with similar findings for in-lesion MLD.

Late-loss numbers, however, were exceedingly small for both treatment groups: 0.04 mm for the stent group and 0.14 mm for the DEB group. Clinical events were rare in both groups at one year.

Both treatments, Alfonso concluded, "provide excellent long-term results," although larger and longer follow-up trials are needed.

Experts discussing the results following a presentation to the press were impressed by the very limited late loss in both arms, noting that the use of a stent scaffold itself would have given a bit of an MLD boost to this arm of the study.

Dr Philippe Généreux (Hôpital du Sacré Coeur de Montréal, QC) commented, "I'm very impressed by the late loss in both arms" but added, "The real question is how this will be translated into the real world."

Others noted that early predictions had been that DEB would be "relegated to the periphery" where DES are not an option due to concerns about stent fracture. Data like RIBS V suggest there may yet be a role for drug-eluting balloons in the coronaries, particularly in people with recurrent stent restenosis, to avoid a situation where there are multiple layers of metal in the vessel.

Asked in whom he might use a DEB rather than a stent, Alfonso also cited the example of a patient with restenosis but also patients with lesions complicated by large side branches as well as patients at higher risk of bleeding.

Rosenfield disclosed being a consultant for Abbott Vascular, holding equity in Primacea, receiving research or fellowship support from Abbott Vascular, Atrium, Lutonix-Bard, and IDEV and being a board member for VIVA. Alfonsohad no conflicts of interest.

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