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

Abstract

Current heart valve replacements lack durability and sustained performance, especially in paediatric patients. In part, these problems may be attributed to the materials chosen for these constructs, but an important contributing factor is the design of the valve, as this dictates haemodynamic 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 stent posts, secured to a sewing ring. This overall design strategy is effective, but functionality and durability may be improved by incorporating features of the native valve geometry. This paper presents a novel workflow for developing and analysing bioinspired valve designs computationally. The leaflet curvature was defined using a mathematical equation that was derived from the 3D model of a native sheep pulmonary valve obtained via micro-computed 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, Geometric Orifice Area (GOA) and the stress in the leaflets. This workflow demonstrated benefits for valve designs with leaflet thicknesses between 0.1-0.3 mm, Young's moduli less than 50 MPa, and elongated leaflets with greater curvatures. The proposed workflow brings substantial efficiency gains, minimising manufacturing and animal testing during iterative improvements, and offers a bridge between in vitro and more complex in silico studies in the future.

The Effect of Bileaflet Mechanical Heart Valve Designs on Biomechanical Behaviours – A Finite Element Analysis

“…Ischemic heart disease is the most common type of the cardiovascular diseases which usually then followed by stroke and chronic obstructiveness with a total death estimation of 11% and 6%, respectively. Besides, another disease that associated with the heart but hardly known is valvular heart disease [1,2]. This disease is associated with aortic and mitral roots enlargement that affects blood flow.…”

“…Little is aware on the importance of the heart valve function where the problematic heart valve could result in regurgitation by which the blood flows backward in the heart. Further to that, stenosis may also occur [2]. Stenosis is a condition when the opening of blood flow is narrowed or stiffened causing the blood to be accumulated and pressurised [3].…”

“…The first replacement of the heart valve on human was performed in 1961 [5]. Generally, the prosthetic heart valve can be categorised into two main groups which are the bioprosthetic and mechanical types [2,6]. In comparison to the bioprosthetic valves, the mechanical valves have a higher risk of blood clot formation and severe bleeding due to mandatory anticlotting medication [7].…”

Bioinspired polymeric heart valves: A combined in vitro and in silico approach

“…This study is a continuation of our previously developed bioinspired valve design, in which we used computed tomography scan images of native pulmonary valves to derive geometries based on the native valve. 13 In the present study, the valves were downsized from 30 mm (adult) to 18 mm (pediatric) in diameter to test their performance in the pulmonary position and the suitability for pediatric patients. The geometry of leaflet free edges was improved to minimize commissural gaps.…”

“…In addition, a fluid–structure interaction (FSI) simulation was performed using an arbitrary Lagrangian-Eulerian (ALE) coupled to an immersed solid approach instead of conducting a structural analysis alone which was shown in our previous work. 13 This allowed us to account for the impact of the fluid motion and calculate the EOA in silico. In the FSI simulation, the performance of bioinspired valves was assessed for systolic function and stress distribution.…”