Valve Underexpansion and Clinical Outcomes With ACURATE neo2: Findings From the ACURATE IDE Trial.

Background: In the ACURATE IDE (Safety and Effectiveness Study of ACURATE Valve for Transcatheter Aortic Valve Replacement) randomized controlled trial, ACURATE neo2 failed to show noninferiority to commercially available balloon-expandable (SAPIEN 3/3 Ultra) and self-expanding (Evolut R/PRO/PRO+/FX) valves for the primary endpoint of all-cause mortality, stroke, or rehospitalization at 1 year. A retrospective investigation was undertaken to evaluate potential factors contributing to these outcomes.

Objectives: The goal of this study was to assess the impact of ACURATE neo2 valve expansion on clinical outcomes in the ACURATE IDE trial.

Methods: Post hoc case review identified angulated (nonparallel) commissure posts in a few implanted ACURATE neo2 valves, indicating valve underexpansion. Procedural angiograms for all ACURATE neo2 valves implanted in the trial's main randomized cohort (n = 752) were inspected by an independent core laboratory. An exploratory analysis was performed to evaluate the association between valve expansion and clinical outcomes.

Results: Of the 624 patients who underwent implantation with the ACURATE neo2 and had evaluable procedural angiograms, 135 (21.6%) had underexpanded valves. Greater aortic valve leaflet and annulus calcification at baseline was independently associated with ACURATE neo2 valve underexpansion (OR: 1.92; 95% CI: 1.27-2.91; P = 0.002). Procedural techniques, including frequency of predilation (100% in both groups) and postdilation (26.7% vs 25.2%; P = 0.72), and balloon sizing did not differ between the underexpanded and expanded valve groups. ACURATE neo2 underexpansion was associated with a higher 1-year rate of death, stroke, or rehospitalization (underexpanded: 18.7%; expanded: 11.8%; P = 0.04), which was confirmed in a multivariable analysis (HR: 1.92; 95% CI: 1.27-2.91; P = 0.002).

Conclusions: Underexpansion of the ACURATE neo2 valve in the ACURATE IDE study was associated with a higher risk of the composite endpoint of death, stroke, or rehospitalization. Given the post hoc nature of these analyses, the study findings should be considered hypothesis generating. Whether achieving optimal valve expansion of the ACURATE neo2 valve with improvement in device design and procedural iterations will translate into improved clinical outcomes remains to be studied.