A post hoc analysis of the ACURATE IDE trial has found that underexpansion of the ACURATE neo2 transcatheter heart valve (THV) was associated with a higher rate of adverse clinical outcomes at one year.¹ The original trial failed to demonstrate non-inferiority of the ACURATE neo2 valve compared with contemporary commercial valves for the primary endpoint of all-cause mortality, stroke, or rehospitalisation.² This new investigation sought to identify potential contributing factors.

This retrospective, exploratory analysis reviewed data from the ACURATE IDE trial, a multicentre, randomised, controlled, non-inferiority study. Investigators identified valve underexpansion, indicated by angulated (nonparallel) commissure posts on procedural angiograms, in some implanted ACURATE neo2 valves.

An independent core laboratory inspected procedural angiograms for all 752 patients in the trial’s main randomised cohort who received the ACURATE neo2 valve. The analysis focused on 624 patients with evaluable angiograms, assessing the association between valve expansion and the 1-year composite endpoint of death, stroke, or rehospitalisation.

Of the 624 patients with evaluable angiograms, 135 (21.6%) were found to have underexpanded ACURATE neo2 valves. The analysis revealed that greater aortic valve leaflet and annulus calcification at baseline was an independent predictor of valve underexpansion (OR: 1.92; 95% CI: 1.27–2.91; P=0.002).

Procedural techniques, including the rates of predilation (100% in both groups) and postdilation (26.7% in the underexpanded group vs 25.2% in the expanded group; P=0.72), did not significantly differ between the two groups.

Crucially, ACURATE neo2 underexpansion was associated with a significantly higher 1-year rate of the primary composite endpoint (18.7% vs 11.8%; P=0.04). This finding was confirmed in a multivariable analysis, which showed underexpansion was linked to a nearly two-fold increased risk of death, stroke, or rehospitalisation (HR: 1.92; 95% CI: 1.27–2.91; P=0.002).

This analysis suggests that suboptimal mechanical deployment, particularly in heavily calcified anatomies, may have contributed to the inferior outcomes observed with the ACURATE neo2 valve in the ACURATE IDE trial. The findings highlight the critical importance of achieving full stent frame expansion during transcatheter aortic valve replacement (TAVR) to ensure optimal haemodynamics and clinical results. As the authors, led by Dr Raj R. Makkar from Cedars-Sinai Medical Center, Los Angeles, US, noted, the findings from this post hoc analysis should be considered hypothesis-generating.

The study authors concluded that it "remains to be studied" whether achieving optimal valve expansion of the ACURATE neo2 valve, through improvements in device design and procedural iterations, will translate into improved clinical outcomes.

References

1. Makkar RR, Chakravarty T, Gupta A, et al. Valve underexpansion and clinical outcomes with ACURATE neo2: findings from the ACURATE IDE trial. JACC. 2025;86(4):225–238. https://doi.org/10.1016/j.jacc.2025.05.011

2. Makkar RR, Ramana RK, Gnall E, et al. ACURATE neo2 valve versus commercially available transcatheter heart valves in patients with severe aortic stenosis (ACURATE IDE): a multicentre, randomised, controlled, non-inferiority trial. Lancet. 2025;405(10494):2061-2074. https://doi.org/10.1016/S0140-6736(25)00319-8

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