Flat or curved pericardial aortic valve cusps: a finite element study.

BACKGROUND AND AIM OF THE STUDY The finite element method (FEM) has frequently been used to investigate the behavior of the aortic valve, but studies on the performance and behavior of free-hand autologous pericardial aortic valves reconstructed using specially designed valve molds have not been performed. The study aim was to demonstrate the effectiveness of a three-dimensional (3-D) cusp of the authors' design (H-Mold) versus a two-dimensional (2-D) (flat) cusp using a FEM to compare stress distribution and leaflet contact properties. METHODS Solid models of the aortic root and valve cusps were constructed using a computer-aided design package. All models had different free edge lengths and surface areas, but a constant leaflet attachment length corresponding to a 19 mm annulus diameter. A static pressure of 80 mmHg was applied to all models. RESULTS The maximum von Mises stress value in the H-Mold at the cusp commissure was 34.5% lower than the stress value in the flat leaflet, while the contact area in the H-Mold leaflet was 85.7% greater than that of the flat leaflet. The length of leaflet free edge greatly influenced maximum von Mises stress intensity at the commissures, and the contact area between leaflets was mainly affected by the geometric shape of the leaflet and its surface area. CONCLUSION 3-D leaflet geometry was found positively to influence leaflet stress distribution and coaptation. This geometry should have a significant impact on the reliability and long-term durability of pericardial aortic valve reconstruction.