Lotus Valve Tops CoreValve on Some Measures in Single-Center, Nonrandomized Study
In a small, early comparison, a novel repositionable valve yields greater device success than a self-expanding valve in high-risk TAVR patients, according to a paper published in the June 2015 issue of JACC: Cardiovascular Interventions.
But whether the apparent safety and efficacy advantages translate into clinical superiority requires testing in large randomized trials, the authors say.
Ian T. Meredith, MBBS, PhD, of Monash Heart (Clayton, Australia), and colleagues compared outcomes of 50 high-risk TAVR patients who received the mechanically expanded Lotus valve (Boston Scientific) and 50 similar patients who were implanted with the self-expanding CoreValve (Medtronic) at their institution during the same period. All procedures were performed with transfemoral access. Mean age was 83.4 years, 44% of patients were men, and mean STS score was 5.5.
Baseline characteristics were similar between groups with the exception of the presence of more patients with NYHA class IV heart failure in the Lotus group and more patients with preexisting A-fib in the CoreValve group. In addition, there were no differences in echocardiographic parameters except for a slightly more eccentric basal plane in the CoreValve cohort.
The smallest Lotus device (23 mm) was implanted in 52% of the Lotus group, while 44% of the CoreValve group received the smallest 26-mm CoreValve device (P < .001). Both perimeter and area oversizing were more common in the CoreValve group (P < .001).
VARC2-defined device success (primary endpoint) was higher in the Lotus group, driven by higher rates of correct positioning of a single device and no more than mild aortic regurgitation (table 1). No differences were seen in other components of success, including procedural mortality, transprosthesis mean gradient no greater than 20 mm Hg, and absence of prosthesis-patient mismatch. Rates of cardiovascular mortality, need for permanent pacemaker, and major stroke were similar between the groups at 30 days.
Rates of acute kidney injury, minor or major vascular injury, disabling or nondisabling stroke, and periprocedural MI also were similar.
Improved Design Features
Dr. Meredith and colleagues say the improved success rate with the Lotus device may be due to its “novel features.”
“The Lotus is totally repositionable, even when fully expanded in the final position, by virtue of its deployment and coupling mechanism,” they write. “This enables detailed interrogation of the device function, degree of [aortic regurgitation], and device stability before uncoupling and release. In addition, the presence of an adaptive seal around the outer aspect of the lower valve frame appears to reduce [aortic regurgitation] by occupying residual interstices between the frame and native annulus.”
The single-arm REPRISE I and REPRISE II trials have demonstrated the safety and efficacy of the Lotus valve, but to date there have been no data from head-to-head comparisons of the newer-generation device with other valves.
However, the ongoing randomized REPRISE III trial, with a planned enrollment of just over 1,000 patients, is comparing the safety and efficacy of Lotus vs CoreValve out to 1 year.
A Glimpse of Things to Come?
In a telephone interview with TCTMD, Ted Feldman, MD, of Evanston Hospital (Evanston, IL), principal investigator of REPRISE III, said the current study—while limited by both being nonrandomized and conducted in a single center—“does give us a preview of what we might expect from both the worldwide RESPOND registry and from the REPRISE III trial.”
Dr. Feldman said the findings are “what we would expect from such a comparison, in that the big clinical endpoints like mortality and stroke are not different… but paravalvular leak and VARC2- defined success are superior for Lotus. All of that makes sense given the proper use of the 2 platforms.”
Aggregate CoreValve first-generation experience has “clearly shown that paravalvular leak is part of that platform… regardless of what we have tried to do to [minimize it],” he said, adding that, conversely, both REPRISE II and early data from the RESPOND registry indicate that paravalvular leak is virtually a nonissue with Lotus.
Need for valve-in-valve implantation due to “pop-outs” is another important consideration with CoreValve and occurs about 2% to10% of the time, Dr. Feldman noted. “With the retrievable valve it will be nonexistent or very rare that you will need a second valve or valve-in-valve.”
But for now, assumptions that Lotus could become the preferred valve in the future need to be put on hold until the randomized data are available, Dr. Feldman cautioned, noting that other next-generation TAVR devices, such as Sapien 3 (Edwards Lifesciences), likewise appear to result in very low paravalvular leak and valve-in-valve rates.
Gooley RP, Talman AH, Cameron JD, et al. Comparison of self-expanding and mechanically expanded transcatheter aortic valve prostheses. J Am Coll Cardiol Intv. 2015;8:962-971.
- Dr. Meredith reports receiving modest consulting fees from Boston Scientific and serving on the strategic advisory boards of Boston Scientific and Medtronic.
- Dr. Feldman reports receiving research grants and consulting fees from Abbott Vascular, Boston Scientific, and Edwards Lifesciences.