Mechanical testing of glutaraldehyde cross-linked mitral valves. Part two: Elastic and viscoelastic properties of chordae tendineae

Research output: Contribution to journalArticlepeer-review

Authors

  • Matthew Constable
  • Rhiannon Northeast
  • Vera Gramigna
  • Kheng Lim Goh
  • Keith G. Buchan

Colleges, School and Institutes

External organisations

  • University of Birmingham
  • University of Catanzaro Magna Græcia
  • Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR)
  • University of Newcastle
  • Aberdeen Royal Infirmary

Abstract

The aim of this study was to assess whether the mechanical properties of mitral valve chordae tendineae are sensitive to being cross-linked under load. A total 64 chordae were extracted from eight porcine hearts. Two chordae (posterior basal) from each heart were subjected to uniaxial ramp testing and six chordae (two strut, two anterior basal and two posterior basal) were subjected to dynamic mechanical analysis over frequencies between 0.5 and 10 Hz. Chordae were either cross-linked in tension or cross-linked in the absence of loading. Chordae cross-linked under load transitioned from high to low extension at a lower strain than cross-linked unloaded chordae (0.07 cf. 0.22), with greater pre-transitional (30.8 MPa cf. 5.78 MPa) and post-transitional (139 MPa cf. 74.1 MPa) moduli. The mean storage modulus of anterior strut chordae ranged from 48 to 54 MPa for cross-linked unloaded chordae, as compared to 53–61 MPa cross-linked loaded chordae. The mean loss modulus of anterior strut chordae ranged from 2.3 to 2.9 MPa for cross-linked unloaded chordae, as compared to 3.8–4.8 MPa cross-linked loaded chordae. The elastic and viscoelastic properties of chordae following glutaraldehyde cross-linking are dependent on the inclusion/exclusion of loading during the cross-linking process; with loading increasing the magnitude of the material properties measured.

Details

Original languageEnglish
JournalProceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Early online date27 Nov 2020
Publication statusE-pub ahead of print - 27 Nov 2020

Keywords

  • Chordae tendineae, dynamic mechanical analysis, glutaraldehyde, mechanical properties, mitral valve, uniaxial testing, viscoelasticity

ASJC Scopus subject areas