TCT-16: Halloween 'Magic,' Some Tricks, and a Lot of Treats

October 24, 2016

WASHINGTON, DC — One of the best "tricks" featured throughout the upcoming Halloween-season TCT-16 conference is a real disappearing act—a wave of studies comparing standard drug-eluting stents (DES) and bioresorbable vascular scaffolds (BVS)—is a sure sign that the latter technology is steadily maturing.

At the meeting's high-profile late-breaking clinical-trial (LBCT) and first report investigation presentations, iterations of the drug-delivering coronary stents that vanish over time or whose polymer coats vanish overshadow other familiar transcatheter technologies that are no longer "emerging" but still offer a lot to explore.

Among the most anticipated studies are two looking at cerebral protection devices to accompany transcatheter aortic-valve replacement (TAVR); and close looks at two left atrial appendage (LAA) closure devices, including the Watchman (Boston Scientific) postmarketing study. The devices are seen as shields against cardiogenic strokes as a complement to or substitute for oral anticoagulation.

Standard DES are getting some spotlight too, as they go up against CABG in the still-unsettled domain of left main (LM) coronary disease in two parallel randomized trials, one using everolimus DES and the other biolimus DES.

Dr Gregg W Stone

Those randomized "strategy" trials, called EXCEL and NOBLE, respectively, could have "an immediate impact on practice, whether positive or negative," according to TCT-16 director Dr Gregg W Stone (Cardiovascular Research Foundation, New York, NY).

That's in large part because in general, earlier trials comparing PCI and CABG in LM disease, such as PRECOMBAT and SYNTAX, had only a few hundred patients or an LM subcohort totaling only about 700, respectively.

But the field has gone a long way since those trials, and EXCEL and NOBLE together total about 3100 patients. So they include "four to five times as many patients as we've had from previous well-done trials of left main coronary artery disease," according to Stone.

"I think that these trials have the potential to really confirm that PCI should or should not be performed in left main disease."

TCT-16 attendees might be forgiven if they forget interventional procedures for a while as the meeting hands the ball off to several featured speakers. They include businessperson, philanthropist, and HIV activist Earvin Johnson, who anyone following basketball during the 1980s and 1990s would also know as LA Lakers point guard and Olympic "Dream Team" gold medalist "Magic" Johnson. His Monday-night keynote address is slated for the main arena (ballroom level 3) at the Washington Convention Center that is home to the LBCTs and First Reports.

Also addressing the TCT-16 attendees: award-winning presidential biographer and former Newsweek editor in chief Jon Meacham, who could well have special insights about pressing world events as well as a time-honored US tradition taking place on November 8; and an address from FDA commissioner and cardiology native son Dr Robert M Califf, who was a longtime senior contributor to theheart.org on Medscape.

Imaging Evaluations of DES, BVS

Scheduled to launch the first LBCT session at 9 am Sunday, the randomized ILUMIEN III trial compared three imaging modalities as guides for coronary stenting: optical coherence tomography (OCT), intravascular ultrasound (IVUS), and contrast angiography. With a planned enrollment of 450 patients, the trial's primary end points include in-hospital minimal stent area and major adverse cardiac events.

Following that is the BIO-RESORT (TWENTE III) trial, which randomized patients to the Orsiro (biodegradable polymer, sirolimus-eluting stent, Biotronik), the Synergy (biodegradable polymer, everolimus-eluting stent, Boston Scientific), and the Resolute Integrity (durable polymer zotarolimus-eluting stent, Medtronic) devices in an "all-comers" population; the report will cover >2300 patients with coronary disease, according to Stone.

Next up: the phase 2 BIONICS randomized comparison of the novel BioNIR ridaforolimus-eluting stent (Medinol) vs a zotarolimus-eluting stent, with target-lesion failure at 12 months as the primary end point. Stone said this is "the US approval study" that will be shown to regulators.

Stent or CABG in Left Main Disease?

The 12:15 pm Monday First Report session will feature long-term follow-up analyses from the ABSORB China and ABSORB II trials comparing an everolimus BVS vs a metal everolimus DES in patients with coronary disease. The BVS had been shown noninferior to the DES at 1 year in the primary trials; these analyses are to see whether those results apply at 2 or 3 years, according to Stone.

The LEADERS FREE 2-year follow-up is next, a comparison of a drug-coated polymer-free stent (BioFreedom, Biosensors International) and a bare-metal stent (Gazelle, Biosensors) in patients with coronary disease.

The Monday LBCT session at 9:00 am is devoted to the EXCEL and NOBEL comparisons of DES vs CABG in "selected patients" with LM disease. And the Monday First Reports feature "the first substantial data released for five new stents or scaffolds." The trials, most including OCT, IVUS, and contrast angiography comparisons for the stents, include the REVELUTION trial of a "sirolimus-filled" DES (Medtronic) and four BVS trials: FANTOM II, MeRes-1, FORTITUDE, and FUTURE-I .

The third LBCT session at 9:00 am Tuesday features the eponymous SENTINEL randomized trial of the Sentinel cerebral protection system (Claret Medical) used during TAVR. The trial, with a planned enrollment of >360 patients, should "determine, by both clinical events and diffusion-weighted MRI, in a large randomized fashion whether embolic protection of the cerebrovasculature can reduce cerebrovascular events," according to Stone.

On the schedule following SENTINEL are follow-ups to two influential trials, the PARTNER I 5-year echo analysis and PARTNER 2 quality-of-life substudy.

PFO Closure and Strokes

The First Reports at 12:15 pm lead off with the "final" long-term follow-up results of the RESPECT randomized evaluation of the Amplatzer patent foramen ovale (PFO) occluder (St Jude Medical) in patients with prior cryptogenic stroke. Although there was no benefit to the device in the primary analysis, "with longer and longer follow-up, the outcomes have become more and more positive," Stone said.

"And now the intention-to-treat primary end point has become positive, and this may lead to FDA approval of PFO-closure devices, at least this one PFO closure device, in the United States."

The RESPECT analysis is followed by the COLOR registry analysis looking at the relationship between coronary plaque lipid content by near-infrared spectroscopy and stenting outcomes at 2 years; the PLATINUM DIVERSITY prospective registry of coronary stent use in women and minorities, "by far the largest study ever to study the outcomes of both those two cohorts of patients," according to Stone, and the ReACT trial, "the first prospective randomized trial of routine angiographic follow-up" after coronary stenting.

Planned for the Wednesday 9:00 am LBCTs are the multicenter, prospective Watchman postapproval study and the large, European registry analysis Amplatzer Amulet Observational Study, both of LAA-closure devices intended to prevent cardiogenic stroke.

Next in line, the ILLUMENATE randomized safety and efficacy study of the CVI (Spectranetics) paclitaxel-coated balloon catheter for patients with superficial femoral and popliteal artery disease, pitted against a comparable uncoated balloon.

The Big Finale

Then at 12:15 pm on this final day of TCT-16, a First Report session will lead with the PRISON IV randomized comparison of a sirolimus BVS and a durable-polymer everolimus stent in patients with chronic total occlusions (CTO), which could potentially show BVS to be a breakout therapy for such tough-to-treat coronary lesions.

Then the phase-2 TOSCA-5 randomized trial will look at a "fibrolysis" strategy for coronary CTO. The dose-ranging study in 76 patients looked at an infusion of collagenase to "to soften the proximal fibrous cap of the chronic total occlusion to facilitate wire passage," Stone said.

Next is TRANSFORM-OCT, which uses OCT to compare BVS and standard DES strut apposition, "which is becoming an important surrogate end point for safety," according to Stone.

Then, the RIBS VI registry, "the first such study to look at bioresorbable vascular scaffolds as treatment for in-stent restenosis," he said. "So far, everolimus-eluting stents have proved to be the best treatment for in-stent restenosis," but the downside is addition of "another stent layer" to the first stent. So the large RIBS VI registry looked at the use of everolimus BVS in such lesions, on the hope that "3 years later, the lumen will continue to grow as the scaffold resorbs."

Stone has disclosed no relevant financial relationships.

Follow Steve Stiles on Twitter: @SteveStiles2. For more from theheart.org, follow us on Twitter and Facebook .

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