The Impact of Thickness Heterogeneity on Soft Tissue Biomechanics: A Novel Measurement Technique and a Demonstration on Heart Valve Tissue

This study developed a rapid, non-destructive optical profilometry technique to map soft tissue thickness heterogeneity and demonstrated its biomechanical significance using ovine mitral valve leaflets. The authors compared tissue mechanics under biaxial tension, bending, and buckling, both with and without accounting for spatial thickness variation. Using computational modeling validated by mechanical testing, they showed that assuming uniform thickness can introduce errors up to 60% in stress and deformation predictions. The method revealed that native valve leaflets exhibit thinner regions at sites of folding, demonstrating that local thickness heterogeneity directly influences mechanical behavior, anisotropy, and buckling patterns. This framework highlights the need to incorporate true thickness maps into soft tissue models for accurate biomechanical interpretation.