An investigation of the effect of freezing storage on the biaxial mechanical properties of excised porcine tricuspid valve anterior leaflets

Grace A Duginski; Colton J Ross; Devin W Laurence; Cortland H Johns; Chung-Hao Lee

doi:10.1016/j.jmbbm.2019.103438

An investigation of the effect of freezing storage on the biaxial mechanical properties of excised porcine tricuspid valve anterior leaflets

J Mech Behav Biomed Mater. 2020 Jan:101:103438. doi: 10.1016/j.jmbbm.2019.103438. Epub 2019 Sep 16.

Authors

Grace A Duginski¹, Colton J Ross², Devin W Laurence³, Cortland H Johns⁴, Chung-Hao Lee⁵

Affiliations

¹ Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA. Electronic address: duginskiga@ou.edu.
² Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA. Electronic address: cjross@ou.edu.
³ Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA. Electronic address: dwlaur@ou.edu.
⁴ Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA. Electronic address: Cortland.H.Johns-1@ou.edu.
⁵ Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, Norman, OK, 73019, USA; Institute for Biomedical Engineering, Science and Technology, School of Aerospace and Mechanical Engineering (IBEST), The University of Oklahoma, Norman, OK, 73019, USA. Electronic address: ch.lee@ou.edu.

Abstract

The atrioventricular heart valve (AHV) leaflets are critical to the facilitation of proper unidirectional blood flow through the heart. Previously, studies have been conducted to understand the tissue mechanics of healthy AHV leaflets to inform the development of valve-specific computational models and replacement materials for use in diagnosing and treating valvular heart disease. Generally, these studies involved biaxial mechanical testing of the AHV leaflet tissue specimens to extract relevant mechanical properties. Most of those studies considered freezing-based storage systems based on previous findings for other connective tissues such as aortic tissue or skin. However, there remains no study that specifically examines the effects of freezing storage on the characterized mechanical properties of the AHV leaflets. In this study, we aimed to address this gap in knowledge by performing biaxial mechanical characterizations of the tricuspid valve anterior leaflet (TVAL) tissue both before and after a 48-h freezing period. Primary findings of this study include: (i) a statistically insignificant change in the tissue extensibilities, with the frozen tissues being slightly stiffer and more anisotropic than the fresh tissues; and (ii) minimal variations in the stress relaxation behaviors between the fresh and frozen tissues, with the frozen tissues demonstrating slightly lessened relaxation. The findings from this study suggested that freezing-based storage does not significantly impact the observed mechanical properties of one of the five AHV leaflets-the TVAL. The results from this study are useful for reaffirming the experimental methodologies in the previous studies, as well as informing the tissue preservation methods of future investigations of AHV leaflet mechanics.

Keywords: Biaxial mechanical testing; Freezing storage effects; Heart valve biomechanics; Stress relaxation; The tricuspid valve.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Biomechanical Phenomena
Cryopreservation*
Mechanical Phenomena*
Swine
Tricuspid Valve / cytology*
Tricuspid Valve / physiology

Grants and funding

16SDG27760143/AHA_/American Heart Association-American Stroke Association/United States