Scientific Publications by FDA Staff

J Biomech Eng 2019 Jul 17 [Epub ahead of print]

A computational study on deformed bioprosthetic valve geometries: clinically relevant valve performance metrics.

Jafar R, Labrosse M, Weaver JD, Retta SM, Wu C, Duraiswamy N

Transcatheter aortic valves (TAV) are symmetrically designed, but they are often not deployed inside cylindrical conduits with circular cross-sectional areas. Many TAV patients have heavily calcified aortic valves, which often result in deformed prosthesis geometries after deployment. We investigated the effects of deformed valve annulus configurations on a surgical bioprosthetic valve as a model for TAV. We studied valve leaflet motions, stresses and strains, and analogue hydrodynamic measures (using geometric methods), via finite element modeling. Two categories of annular deformations were created to approximate clinical observations: 1) non-circular annulus with valve area conserved, and 2) under-expansion (reduced area) compared to circular annulus. We found that under-expansion had more impact on increasing stenosis than non-circularity, and that non-circularity had more impact on increasing regurgitation than under-expansion. We found durability predictors (stress/strain) to be highest in commissure regions of non-circular configurations. This study adds more evidence for considering the clinical impacts of TAV deformation on acute and long-term valve performance in the design and testing phase of device development.