The Measurement of Bovine Pericardium Density and Its Implications on Leaflet Stress Distribution in Bioprosthetic Heart Valves.

Purpose: Bioprosthetic Heart Valves (BHVs) are widely used in clinical practice, showing promising outcomes. Computational modeling offers a valuable tool for quantitatively characterizing BHVs. To ensure the accuracy of computational models, it is crucial to consider precise leaflet properties, including mechanical properties and density. Bovine pericardium (BP) serves as a common material for BHV leaflets. Previous computational studies often assume BP density to approximate that of water or blood. Given that BP leaflets undergo various treatments, such as tissue fixation and anti-calcification, this study aims to measure the density of BP used in BHVs and assess its impact on leaflet stress distribution.

Methods: Eight square BP samples were laser cut from Edwards BP patches and their density was determined. Specimen weight was measured using an A&D Analytical Balance, while volume was assessed through high-resolution imaging. Additionally, finite element models resembling a BHV, like the Carpentier-Edwards PERIMOUNT Magna, were constructed in ABAQUS.

Results: The average density of the BP samples was found to be 1,410 kg/m. During the acceleration phase of a cardiac cycle, the maximum stress reached 1.89 MPa for a density of 1,410 kg/m and 2.47 MPa for a density of 1,000 kg/m (a 30.7% difference). In the deceleration phase, the maximum stress reached 713 kPa and 669 kPa, respectively.

Conclusion: Leaflet stress distribution and motion in BHVs are influenced by density variations. Establishing an accurate density value for BHV leaflets is imperative for enhancing the computational models, which can ultimately contribute to improved BHV design and outcomes.