Biaxial Strain Distributions in Explanted Porcine Bioprosthetic Valves
Margaret M. Adamczyk PhD, Ivan Vesely PhD

Testing whole explanted porcine bioprosthetic valves may provide insight into changes that occur in bioprostheses in vivo. This information may help elucidate a mechanism of valve failure. The strain distributions of three bioprosthetic heart valves were measured with a whole-valve optical strain mapping system. Pressure versus strain curves were generated, and maximum cusp strain and stiffness were computed. Cusp extensibility was extremely low (2-10%), regardless of direction. For two valves, the non-coronary (NC) cusp was less extensible than the left (LC) and right coronary (RC) cusps. For the third valve, the lowest strains were seen in regions with large deposits of calcification. Negative strains was present primarily in one of the bioprosthetic valves. It is concluded that cusp anisotropy and heterogeneity are preserved in porcine bioprostheses, even though extensibility is dramatically reduced.