Data from the REPRISE III trial indicate that the Lotus transcatheter aortic valve implantation (TAVI) device (Boston Scientific) is associated with a significantly lower rate of death, disabling stroke, and moderate or greater paravalvular leak at one year than is CoreValve (Medtronic). However, because of a problem with the locking mechanism of the delivery system, the Lotus device was pulled from the European market in February 2017.
Presenting the results at EuroPCR (16–19 May, Paris, France), Ted Feldman (Cardiology Division, Evanston Hospital, NorthShore University health System, Evanston, USA) reported that suboptimal deployment and paravalvular leak were, at the time that REPRISE III was designed, among the main limitations of TAVI. He added that the Lotus valve was designed to overcome these limitations, noting that it was “fully repositionable and retrievable” and that it had an “adaptive seal to minimise paravalvular leak”. Furthermore, it has a controlled mechanical expansion and rapid pacing is not needed during deployment, and it allows complete assessment before release so that the operator can reposition/retrieve the device if not in an optimal position.
In the study, patients with severe aortic stenosis at extreme or high surgical risk—after assessment by the heart ream—were randomised (2:1) to CoreValve (305, 153 of whom received the first-generation CoreValve device and 144 received CoreValve Evolut R) or Lotus (607). All patients received dual antiplatelet therapy for at least one month post procedure or warfarin plus aspirin/clopidogrel (if anticoagulation was needed). The primary safety endpoint was a composite of all-cause mortality, stroke, life-threatening and major bleeding events, acute kidney injury, and major vascular complications at 30 days. The primary efficacy endpoint was a composite of all-cause mortality, disabling stroke, and moderate or greater paravalvular leak at one year.
The non-inferiority criteria were met for the primary safety endpoint in both the intention-to-treat analysis (19% for Lotus vs. for 16.2% for CoreValve; p=0.001 for non-inferiority) and in the implanted analysis (20.3% vs. 17.2%; p=0.003 for non-inferiority). There were also no significant differences in the composite safety endpoint at one year. However, at 30 days, Lotus was associated with significantly more pacemaker implantations (29.1% vs. 15.8% for CoreValve; p<0.001) while CoreValve was associated with a higher incidence of aortic valve malappositioning (8% vs. 0% for Lotus; p<0.001). Regarding the higher pacemaker rate with Lotus, Feldman told Cardiovascular News: “The first-generation Lotus shortens from both ends toward the middle, so there is substantial interaction with the left ventricular outflow tract (LVOT) and conduction system deployment. However, the next-generation system has a redesigned deployment mechanism and shortens from the top (aortic side) down, with less interaction with the LVOT. The first results with this “depth guard” system were reported at the 2017 Cardiovascular Research Technologies (CRT) meeting (18–21 February, Washington, DC, USA) and indicated a hospital discharge new pacemaker rate of <20%.”
In REPRISE III, Lotus was associated with a significantly lower rate of the primary efficacy endpoint in both the intention-to-treat and in the implantation analyses: 16.7% vs. 29% for CoreValve and 16.4% vs. 28.6% for CoreValve, respectively (both p<0.001). In terms of the individual components of the primary endpoint, there were no significant differences between groups in the rate of all-cause mortality, cardiac death or stroke. However, the rate of disabling stroke was higher with CoreValve: 7.1% vs. 3.6% for Lotus (intention-to-treat analysis; p=0.02), and the rate of moderate or greater paravalvular leak was also higher with CoreValve (11.1% vs. 2% for Lotus; p<0.00). Additionally, the rate of valve thrombosis was higher with Lotus (1.5% vs. 0% for CoreValve; p=0.03) and the rate of repeat procedure was higher with CoreValve (2% vs. 1% for Lotus; p=0.007).
Feldman concluded: “The Lotus valve is safe and effective compared to a commercially available self-expanding TAVI valve in this large randomised trial.”
Boston Scientific recalled all ranges of Lotus in February 2017, which Reuters reported was because of a problem related to the locking mechanism of the delivery system. Furthermore, the company has delayed its US marketing application for its Lotus Edge device. “The release pin from the locking mechanism pulled out early in several cases, apparently due to excess tension on the pin due to the manufacturing process. My best understanding is that this manufacturing process issue is resolved,” Feldman noted. He added that the issue did not affect the valve itself.