Annals of Biomedical Engineering

, Volume 34, Issue 10, pp 1509–1518 | Cite as

Planar Biaxial Creep and Stress Relaxation of the Mitral Valve Anterior Leaflet

  • Jonathan S. Grashow
  • Michael S. SacksEmail author
  • Jun Liao
  • Ajit P. Yoganathan


A fundamental assumption in mitral valve (MV) therapies is that a repaired or replaced valve should mimic the functionality of the native valve as closely as possible. Thus, improvements in valvular treatments are dependent on the establishment of a complete understanding of the function and mechanical properties of the native normal MV. In a recent study [Grashow et al. ABME 34(2), 2006] we demonstrated that the planar biaxial stress–strain relationship of the MV anterior leaflet (MVAL) exhibited minimal hysteresis and a stress–strain response independent of strain rate, suggesting that MVAL could be modeled as a “quasi-elastic” material. The objective of our current study was to expand these results to provide a more complete picture of the time-dependent mechanical properties of the MVAL. To accomplish this, biaxial stress-relaxation and creep studies were performed on porcine MVAL specimens. Our primary finding was that while the MVAL leaflet exhibited significant stress relaxation, it exhibited negligible creep over the 3-h test. These results furthered our assertion that the MVAL functionally behaves not as a linear or non-linear viscoelastic material, but as an anisotropic quasi-elastic material. These results appear to be unique in the soft tissue literature; suggesting that valvular tissues are unequalled in their ability to withstand significant loading without time-dependent material effects. Moreover, insight into these specialized characteristics can help guide and inform efforts directed toward surgical repair and engineered valvular tissue replacements.

Biaxial tension Biaxial mechanical properties Creep Heart valves Mitral valve Soft tissue biomechanics Stress relaxation 



This work was funded by NIH grant HL-52009. MSS is an Established Investigator of the American Heart Association.


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Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  • Jonathan S. Grashow
    • 1
    • 2
  • Michael S. Sacks
    • 1
    • 2
    Email author
  • Jun Liao
    • 1
    • 2
  • Ajit P. Yoganathan
    • 3
  1. 1.Department of Bioengineering, Engineered Tissue Mechanics LaboratoryUniversity of PittsburghPittsburghUSA
  2. 2.McGowan Institute for Regenerative MedicineUniversity of PittsburghPittsburghUSA
  3. 3.Wallace H. Coulter Department of Biomedical EngineeringGeorgia Institute of TechnologyAtlantaUSA

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