Selecting the Optimal Graft Commissural Height-to-Annular Diameter Ratio in Valve-Sparing Aortic Root Replacement: Ex-vivo Simulation Using a Novel Ringed Graft

Objective In valve-sparing aortic root replacement (VSARR), restoration of physiologic hemodynamics depends on accurate reconstruction of root geometry. Commissural height relative to annular diameter is recognized as an important determinant of valve competence; however, its optimal relationship has not been quantitatively defined. We investigated this relationship using a novel ringed graft to standardize commissural positioning. Methods Five porcine aortic roots underwent reimplantation using ringed grafts with commissural height–to–annular diameter ratios of 0.85, 1.00, and 1.15 in a randomized order. Hemodynamics were tested on an ex vivo left heart simulator. Leaflet velocities were analyzed from high-speed video. A linear mixed effects model was used to account for the repeated measures experimental design. Results Overall, the 1.00 ring provided the most favorable hemodynamic performance. Aortic regurgitation was lower at 1.00 (1.32±0.32 %) than both 0.85 (2.59±0.36 %, P<0.001) and 1.15 (2.34±0.36, P<0.001). Mean transaortic pressure gradient was lower at 1.00 (13.2±1.59 mmHg) than at 0.85 (23.2±1.14 mmHg, P<0.001). Effective orifice area was higher at 1.00 (2.54±0.30 cm 2 ) than at 0.85 (1.59±0.30 cm 2 , P<0.001) and 1.15 (2.40±0.29 cm 2 , P=0.39). Transvalvular pressure gradient and effective orifice area was similar between 1.00 and 1.15. Total transvalvular energy loss was minimized at 1.00 (145±22.8 mJ) compared to 0.85 (306±19.7 mJ, P<0.001) and 1.15 (196±25.1 mJ, P=0.026). Conclusions A ringed graft with a commissural height-to-annular diameter ratio of 1.00 optimizes regurgitation control, forward flow, and energy dissipation without compromising leaflet dynamics, suggesting its potential use as a guiding tool in valve-sparing aortic root replacement.