Effect of graft sizing in valve-sparing aortic root replacement for bicuspid aortic valve: The Goldilocks ratio

Objective: To investigate the effect of graft sizing on valve performance in valvesparing aortic root replacement for bicuspid aortic valve. Methods: In addition to a diseased control model, 3 representative groups - freeedge length to aortic/graft diameter (FELAD) ratio < 1.3, 1.5 to 1.64, and > 1.7 - were replicated in explanted porcine aortic roots (n = 3) using straight grafts sized respective to the native free -edge length. They were run on a validated ex vivo univentricular system under physiological parameters for 20 cycles. All groups were tested within the same aortic root to minimize inter -root differences. Outcomes included transvalvular gradient, regurgitation fraction, and ori fi ce area. Linear mixed effects model and pairwise comparisons were employed to compare outcomes across groups. Results: The diseased control had mean transvalvular gradient 10.9 +/- 6.30 mm Hg, regurgitation fraction 32.5 +/- 4.91 % , and ori fi ce area 1.52 +/- 0.12 cm 2 . In ex vivo analysis, all repair groups had improved regurgitation compared with control ( P < .001). FELAD < 1.3 had the greatest amount of regurgitation among the repair groups ( P < .001) and 1.5-1.64 the least ( P < .001). FELAD < 1.3 and > 1.7 exhibited greater mean gradient compared with both control and 1.5 to 1.64 ( P < .001). Among the repair groups, 1.5 to 1.64 had the largest ori fi ce area, and > 1.7 the smallest ( P < .001). Conclusions: For a symmetric bicuspid aortic valve, performance after valvesparing aortic root replacement shows a bimodal distribution across graft size. As the FELAD ratio departs from 1.5 to 1.64 in either direction, signi fi cant increases in transvalvular gradient are observed. FELAD < 1.3 may also result in suboptimal improvement of baseline regurgitation. (JTCVS Techniques 2024;25:1-7)