PREPARE-CALC Favors Atherectomy for Heavily Calcified Lesions

Patrice Wendling

October 04, 2018

SAN DIEGO — Up-front high-speed rotational atherectomy (RA) of severely calcified lesions is feasible in nearly all patients and improves the success of drug-eluting stent (DES) implantation compared with modified cutting or scoring balloons, according to results of the PREPARE-CALC trial.

The primary end point of strategy success — defined as successful stent delivery with less than 20% in-stent residual stenosis and achieving a TIMI grade 3 flow without crossover or stent failure — was 98% with RA and 81% with modified balloons (P = .0001).

This was driven by the need for 16 crossovers in the modified balloon group, most commonly because of uncrossable (n = 8) or undilatable (n =  6) lesions, vs none in the RA group (P < .0001).

The coprimary end point of in-stent late lumen loss at 9 months was similar with RA and modified balloons (0.22 mm vs 0.16 mm; P = .02 for noninferiority).

Although both strategies are equally safe and effective, "the use of rotational atherectomy is no longer associated with excessive late lumen loss in the modern era of sirolimus-eluting stents," Gert Richardt, MD, Heart Center, Segeberger Kliniken, Bad Segeberg, Germany, said in a late-breaking clinical science session here at Transcatheter Cardiovascular Therapeutics 2018.

In the 2011 ROTAXUS trial, rotational atherectomy, which modifies plaque by differential cutting, was more successful than standard balloon dilatation but at a cost of higher in-stent late lumen loss.

No randomized trials, however, have compared RA and modified scoring/cutting balloons, which apply focal concentrations of dilating force and produce controlled incisions of the lesions. There is a need for more data, as highly calcified lesions are typically excluded from randomized percutaneous coronary intervention (PCI) trials and are common in the elderly, where there is growing demand for revascularization, he noted.

PREPARE-CALC randomly assigned 200 patients to high-speed RA with the Rotablator (Boston Scientific) or modified balloon angioplasty, most commonly using the AngioSculpt scoring balloon (Biotronik), followed by the Scoreflex scoring balloon (OrbusNeich Medical) and the Flextome cutting balloon (Boston Scientific). All patients underwent PCI with the sirolimus-eluting Orsiro stent (Biotronik).

The patient population (mean age, 75 years; 76% male) was well matched, although the modified-balloon group had more left main disease and a higher maximum stent implantation pressure, whereas the RA group had higher use of a 7-Fr guiding catheter and balloon predilatation and longer fluoroscopy times (23.9 vs 19.6 minutes).

Acute gain after the procedure was very similar in the RA and modified-balloon groups (in-stent, 1.70 vs 1.74 mm; P = .45).

"This is remarkable because we historically know that the rotoablation does better; it achieves more gain than the standard balloon," Richardt said.

Subgroup analyses revealed no RA advantage in women, patients with left anterior descending coronary artery as the target lesion, and those with non-type C lesions, suggest the results, also published online in Circulation: Cardiovascular Interventions.

During a discussion of the results, Jeff Chambers, MD, Metropolitan Heart & Vascular Institute, Minneapolis, questioned whether there was any difference in acute gain based on the type of balloon used and whether new techniques explain the "really surprising" lack of late lumen loss with RA.

Richardt responded that the numbers were too small for subanalyses of acute gain by balloon type and said there was very little difference in the techniques used in PREPARE-CALC and ROTAXUS.

"I think the difference lies in the stent that we used," he said. "This is a modern — some people would say 'best-in-class' — drug-eluting stent, which obviously has the potential to reduce neointima formation."

Analyses are also ongoing to determine whether the use of imaging, such as optical coherence tomography, influences mid-or long-term outcomes.

In a press conference here, Mark Reisman, MD, University of Washington Medical Center, Seattle, pointed out that RA penetration is only about 5% in Europe, but said these results might influence usage and reimbursement. RA use in his own lab is about 15% to 20%, Reisman said in an interview.

"Technically it's more challenging; it's a unique procedure compared to using a balloon, and I think it has a lot of historical baggage with it," he explained. "People have had challenges with it. There are costs and time associated with it, and there was a dynamic, concomitantly when rotoablator was being assessed, where stents were getting easier to use and there were opportunities to challenge those devices in more complex lesions."

Commenting further, Reisman said "now that everything has sort of settled out, it's nice to have this trial reflect these outcomes. I'm not surprised."

Richardt told reporters the trial was not powered for clinical end points but noted that restenosis rates were in the single digits in both groups; target-vessel failure rates were just 6% with RA and 8% with modified balloons (= .78).

"This might increase with time, but it's not so far away from what we see in contemporary DES trials," he added.

In addition to the lack of power for clinical events, Richardt said, other limitations are that crossover is a potential source of bias; a transfemoral approach was mainly used; acute and clinically unstable patients were excluded; and other techniques, such as orbital atherectomy, lasers, and lithoplasty, were not tested.

Asked by the panel following the formal presentation whether these new technologies could be even safer, Richardt replied, "I was a believer in these new technologies, but when I saw the very low event rates after 9 months in this study, I asked myself: What is the additional effect that we can create with these new technologies? Is there still an unmet need that we have to address with these new technologies or are our old tools, if used in the right way, already able to achieve good results?"

The study is funded by the Heart Center, Segeberger Kliniken, Bad Segeberg, Germany. Richardt reports speaker's honoraria from Boston Scientific and Biotronik. Chambers reports consultant fees/honoraria from or speaker's bureau participation with Boston Scientific. Reisman reports consultant fees/honoraria from or speaker's bureau participation with Boston Scientific and equity in Ancora.

Transcatheter Cardiovascular Therapeutics (TCT) 2018. Presented September 24, 2018.

Circ Cardiovasc Interv. Published online September 24, 2018. Abstract

Follow Patrice Wendling on Twitter: @pwendl. For more from theheart.org | Medscape Cardiology, follow us on Twitter and Facebook.

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