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

Perry S Choi; Amit Sharir; Yoshikazu Ono; Masafumi Shibata; Alexander D Kaiser; Yuanjia Zhu; Alison L Marsden; Y Joseph Woo; Michael R Ma; Joon Bum Kim

doi:10.1016/j.xjtc.2024.03.025

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

JTCVS Tech. 2024 Apr 16:25:1-7. doi: 10.1016/j.xjtc.2024.03.025. eCollection 2024 Jun.

Authors

Affiliations

¹ Department of Cardiothoracic Surgery, Stanford University, Palo Alto, Calif.
² Department of Pediatrics, Division of Pediatric Cardiology, Stanford University, Palo Alto, Calif.
³ Department of Thoracic and Cardiovascular Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

Abstract

Objective: To investigate the effect of graft sizing on valve performance in valve-sparing aortic root replacement for bicuspid aortic valve.

Methods: In addition to a diseased control model, 3 representative groups-free-edge 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 orifice 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 orifice area 1.52 ± 0.12 cm². 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 orifice area, and >1.7 the smallest (P < .001).

Conclusions: For a symmetric bicuspid aortic valve, performance after valve-sparing aortic root replacement shows a bimodal distribution across graft size. As the FELAD ratio departs from 1.5 to 1.64 in either direction, significant increases in transvalvular gradient are observed. FELAD <1.3 may also result in suboptimal improvement of baseline regurgitation.

Keywords: David procedure; aortic root replacement; aortic valve repair; bicuspid aortic valve; free-edge length; graft size; valve-sparing aortic root replacement.