Research in context
Evidence before this study
Transcatheter aortic valve replacement (TAVR) with balloon-expandable valves has been associated with favourable clinical outcomes compared with surgical aortic valve replacement in patients with symptomatic severe aortic stenosis across the spectrum of risk. With the anticipated expansion of TAVR into lower-risk patients, transcatheter device-versus-device trials gain increasing relevance in view of periprocedural and long-term outcomes. We searched PubMed and conference abstracts on Aug 5, 2019, with no language restrictions, using the following search terms “transcatheter aortic valve replacement” OR “transcatheter aortic valve implantation” AND “randomized”. Our search found three head-to-head randomised comparisons, two of which compared a balloon-expandable valve with a self-expanding valve. The CHOICE trial showed superior device success in patients treated with second-generation balloon-expandable valves (Edwards SAPIEN XT) compared with first-generation self-expanding valves (CoreValve) in 241 patients with aortic stenosis at high-risk for surgery. The SOLVE-TAVI trial showed equivalence of a newer-iteration balloon-expandable device (Edwards SAPIEN 3) compared with a newer-iteration self-expanding device (Evolut R) with regard to a composite of all-cause death, stroke, moderate-to-severe aortic regurgitation, or permanent pacemaker implantation at 30 days in 447 patients with severe symptomatic aortic stenosis. The ACURATE neo system is a novel, self-expanding transcatheter heart valve that has been associated with similar clinical outcomes, lower transvalvular gradients, and lower rates of permanent pacemaker implantation compared with balloon-expandable valves in a propensity score-matched analysis of 1121 patients. Conversely, rates of paravalvular leakage were higher in patients treated with the ACURATE neo valve compared with those treated with the balloon-expandable SAPIEN 3 prosthesis. No evidence from randomised controlled trials comparing ACURATE neo with the benchmark balloon-expandable SAPIEN 3 system is available.
Added value of this study
The SCOPE I trial is the first randomised trial to compare the self-expanding ACURATE neo valve with the balloon-expandable SAPIEN 3 prosthesis in patients with severe symptomatic aortic stenosis. The study hypothesis of non-inferiority of the ACURATE neo compared with the SAPIEN 3 with regard to a primary safety and efficacy composite endpoint assessed at 30 days was not met. In a secondary analysis, the balloon-expandable SAPIEN 3 device was superior to the self-expanding ACURATE neo device with respect to the primary composite endpoint. The difference was largely driven by valve-related dysfunction due to paravalvular aortic regurgitation as assessed by an independent echocardiographic core laboratory. Most of the individual clinical components of the primary endpoint were similar between groups. The composite safety and efficacy endpoint used in this trial was able to adequately discriminate the performance of individual TAVR devices at short-term follow-up.
Implications of all the available evidence
Conceptual differences between available devices for TAVR affect safety and efficacy endpoints and challenge the generalisability of landmark strategy trials (TAVR vs surgical aortic valve replacement) to all available devices. TAVR with the ACURATE neo device is associated with higher incidence of paravalvular leakage than that of the SAPIEN 3 prosthesis, while rates of death, stroke, and myocardial infarction are similar. An early composite safety and efficacy endpoint could be useful in discriminating the performance of future iterations of TAVR systems.