Mechanical properties of porcine pulmonary valve leaflets: how do they differ from aortic leaflets?

This study measured the biaxial properties of pulmonary and aortic leaflets in extension in the fresh state and then in the same samples after fixation with glutaraldehyde. The results showed that when fresh, the valves had a similar response to load in the circumferential direction, but the pulmonary leaflets were more extensible in the radial direction. They were also less stiff. Fixation decreased the tissue extensibility and increased the stiffness of the pulmonary leaflets much less than in the aortic leaflets. This was interpreted to mean that the collagen content of the pulmonary leaflets is significantly less than that in the aortic leaflets. Reduced collagen content would be expected to enhance hemodynamic performance because of increased leaflet stretch and reduced stiffness. However, lower collagen levels may reduce implant durability.