Background: Limited evidence is available regarding valve-in-valve (VIV) intervention with the ACURATE neo transcatheter heart valve (THV). Low implantation has demonstrated leaflet interaction between the surgical bioprosthesis and the THV, leading to impaired hydrodynamic performance. It is unknown if commissural alignment (CA) can affect this phenomenon. Novel techniques have now been developed to achieve CA with the ACURATE neo THV. Objectives: The aim of this study was to assess the impact of commissural misalignment (CMA) on hydrodynamic function following VIV intervention with the ACURATE neo THV using a bench model. Methods: VIV intervention was performed with the ACURATE neo (a self-expanding THV with supra-annular leaflet position) implanted deep in the surgical bioprosthetic aortic valve (Mitroflow). Hydrodynamic function at CA (0°) and 3 different degrees of CMA (30°, 60°, and 90°) was tested. As per the International Organization for Standardization, a regurgitant fraction <20% is considered optimal. Results: Following VIV, the central THV regurgitant fraction at 0°, 30°, 60°, and 90° of CMA was 8.6% ± 2.0%, 30.3% ± 12.0%, 42.6% ± 11.9%, and 66.7% ± 25.4% (P < 0.0001), respectively. On high-speed video there was no evidence of leaflet interaction at CA, whereas at 30°, 60°, and 90° of CMA there was clear evidence of THV leaflet interaction with those of the surgical valve, leading to impaired leaflet closure and to severe central THV regurgitation. Conclusions: In VIV using the ACURATE neo THV at deep implantation, increasing degree of CMA was associated with THV leaflet interaction with those of the surgical valve and worsening regurgitant fraction. THV leaflet interaction was prevented when there was CA.