Viscoelastic properties of mitral valve leaflets: an analysis of regional variation and frequency-dependency

Jonathan Baxter, Keith G. Buchan, Daniel Espino

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)
252 Downloads (Pure)

Abstract

The aim of this study was to determine the regional variation in viscoelastic properties of mitral valve leaflets over a range of physiological and patho-physiological frequencies. This included comparisons to be made between anterior and posterior leaflets, anterior leaflet clear and rough zones, and radial and circumferential leaflet orientation. Dynamic Mechanical Analysis (DMA) was used to determine frequency-dependent viscoelastic properties. The valve leaflets were dissected from eight porcine hearts. The leaflets were loaded under a sinusoidal tensile displacement, with a mean dynamic peak to trough strain of 11%, applied to all leaflet samples at 9 different frequencies, ranging from 0.5 to 10 Hz. The anterior leaflet has higher storage and loss stiffness than the posterior leaflet. The storage stiffness of circumferential tissue is greater than that of radially orientated valve tissue (2.0 ± 1.6 N/mm cf. 1.7 ± 0.9 N/mm; p < 0.05); however, the loss stiffness is greater for radial tissue (0.15 ± 0.07 cf. 0.14 ± 0.09 N/mm; p < 0.05). Likewise, the storage stiffness of the anterior leaflet clear zone is greater than that of the rough zone (2.4 ± 1.6 cf. 2.1 ± 1.2; p < 0.05), but the loss stiffness is greater for the rough zone (0.17 ± 0.09 N/mm cf. 0.14 ± 0.08 N/mm; p < 0.05). In conclusion, the viscoelastic properties of porcine mitral valve leaflets have regional variations, with dynamic stiffness being dependent on circumferential or radial orientation and on location at a clear or rough zones.
Original languageEnglish
Pages (from-to)938-944
JournalInstitution of Mechanical Engineers. Proceedings. Part H: Journal of Engineering in Medicine
Volume231
Issue number10
Early online date14 Jul 2017
DOIs
Publication statusE-pub ahead of print - 14 Jul 2017

Keywords

  • heart
  • loss
  • mechanical properties
  • mitral value
  • stiffness
  • storage
  • viscoelasticity

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