Impact of leaflet stiffness in aortic valve neocuspidization in ex vivo biomechanical simulation

This study aimed to analyze how varying glutaraldehyde fixation of porcine pericardium impacts the biomechanics of aortic valve neocuspidization (ie, Ozaki procedure).

Four bovine aortic roots were mounted in a 3-dimensional printed left heart simulator. Leaflets were tanned for 2, 6, and 10 minutes in 0.625% glutaraldehyde and used to create the Ozaki models in the same aortic root. Three models were biomechanically compared with a native aortic control valve. Hemodynamics, high-speed videography, and echocardiography data were collected. The flexibility and strength of each pericardium were tested using tensile strength.

Tensile stress and strain were best at 10-minute tanning. As neo-leaflet tanning duration increased from 2 to 10 minutes, the transvalvular pressure gradient decreased by 38.0% (13.7 ± 4.0 mm Hg vs 8.5 ± 4.8 mm Hg, P < .0001). Ozaki models had smaller orifices than native valves (2.0 ± 0.6 cm² vs 1.3 ± 0.2 cm², 1.4 ± 0.3 cm², and 1.5 ± 0.1 cm² for 2, 6, and 10 minutes: P = .0003, P < .002 for 2 and 10 minutes). When tanning time extended from 2 to 10 minutes, valve regurgitation decreased by 31.1% (18.0% vs 12.4%, P < .001). The average valve opening and closing leaflet velocities increased by 38.6% and 22.5% from 2 to 10 minutes of tanning (298.7 vs 486.1 mm/s, P = .048; 188.1 vs 242.7 mm/s, P = .14), respectively.

Porcine pericardium tanned in glutaraldehyde for 10 minutes resulted in the lowest valve regurgitation, lowest pressure gradient, and highest leaflet velocities in ex vivo simulation. These observations can be used to optimize valve function and enhance aortic valve reconstruction techniques.