Functional Mechanics of the Murine Pulmonary Heart Valve. (9th April 2021)

• Record Type: Journal Article
• Authors: Feng, Xinzeng; Liu, Yifei; Liu, Hao; Duong, Channa; Breuer, Christopher K.; McComb, David W.; Sacks, Michael
• Is Part Of: Structural heart. Volume 5(2021)Supplement 1
• Page Start: 41
• Page End: 41
• Publication Date: 2021-04-09
• Subjects: Heart -- Diseases -- Periodicals; Congenital heart disease -- Periodicals; Cardiovascular system -- Diseases -- Periodicals; Cardiovascular Diseases; Cardiovascular system -- Diseases; Congenital heart disease; Heart -- Diseases; Periodicals; 616.12
• DOI: 10.1080/24748706.2021.1900689
• Languages: English
• ISSNs: 2474-8706

Abstract

Abstract : Objective : Measuring the nonlinear elastic properties of murine heart valves is critical for understanding the functional mechanics of heart valves in a gene-modified mouse model. In this study, we propose an integrated imaging/computational approach to estimate the elastic properties of murine heart valves based on the valve geometry at different transvalvular pressure (TVP). Methods : We collected the pulmonary valves (PVs) from eleven 1-year old C57BL/6 mice. Each PV was pressurized hydrostatically (TVP = 10, 20, 30mmHg) and chemically fixated before µCT imaging was done. For each PV, we quantitatively analyzed the segmented geometry in terms of a list of geometric quantities of interest (gQOIs) and central cross-sectional profiles in the circumferential and radial directions. Computationally, we developed a geometric model for the unloaded PV midsurface and a customized finite element program which simulates the closing of PVs under hydrostatic pressure (see Figure 1 ). The optimal parameters for the unloaded PV geometry and elastic properties were obtained by minimizing the difference between the model-predicted and measured gQOIs as well as the central cross-sectional profiles at different TVPs. Herein, the PV was assumed to behave like an anisotropic hyperelastic material with circumferentially-aligned fibers. Results : Consistent trend of gQOIs and cross-sectional profiles were found among different mice. With increasing TVP, less inflation of the radial cross sections was observed due to distention of the pulmonary artery. This phenomenon agreed with our simulation result very well. Conclusions : Our study provides the first estimate for the unloaded geometry and nonlinear elastic properties of murine pulmonary valves. In the long run, this study will facilitate the use of mouse models in the studies for congenital heart diseases and replacement heart valves.