From Scan to Simulation-A Novel Workflow for Developing Bioinspired Heart Valves.

Abstract

Current heart valve replacements lack durability and prolonged performance, especially in pediatric patients. In part, these problems may be attributed to the materials chosen for these constructs, but another important contributing factor is the design of the valve, as this dictates hemodynamic performance and impacts leaflet stresses which may accelerate structural valve deterioration. Most current era bioprosthetic valves adhere to a fundamental design where flat leaflets are supported by commissural posts, secured to a sewing ring. This overall design strategy is effective, but functionality and durability can be improved by incorporating features of the native valve geometry. This paper presents a novel workflow for developing and analyzing bio-inspired valve designs computationally. The leaflet curvature was defined using a mathematical equation whose parameters were derived from the three-dimensional model of a native sheep pulmonary valve obtained via microcomputed tomography. Finite element analysis was used to screen the various valve designs proposed in this study by assessing the effect of leaflet thickness, Young's modulus, and height/curvature on snap-through (where leaflets bend against their original curvature), geometric orifice area (GOA) and the stress in the leaflets. This workflow demonstrated benefits for valve designs with leaflet thicknesses between 0.1 and 0.3 mm, Young's moduli less than 50 MPa, and elongated leaflets with higher curvatures. The proposed workflow brings substantial efficiency gains at the design stage, minimizing manufacturing and animal testing during iterative improvements, and offers a bridge between in vitro and more complex in silico studies in the future.