Effect of glutaraldehyde based cross-linking on the viscoelasticity of mitral valve basal chordae tendineae

Abstract

BackgroundMitral valve failure can require repair or replacement. Replacement bioprosthetic valves are treated with glutaraldehyde prior to implantation. The aim of this study was to determine the changes in mechanical properties following glutaraldehyde fixation of mitral valve chordae.MethodsTo investigate the impact of glutaraldehyde on mitral valve chordae, 24 basal chordae were dissected from four porcine hearts. Anterior and posterior basal (including strut) chordae were used. All 24 chordae were subjected to a sinusoidally varying load (mean level 2N, dynamic amplitude 2N) over a frequency range of 0.5–10 Hz before and after glutaraldehyde treatment.ResultsThe storage and loss modulus of all chordal types decreased following glutaraldehyde fixation. The storage modulus ranged from: 108 to 119 MPa before fixation and 67.3–87.4 MPa following fixation for basal chordae; 52.3–58.4 MPa before fixation and 47.9–53.5 MPa following fixation for strut chordae. Similarly, the loss modulus ranged from: 5.47 to 6.25 MPa before fixation and 3.63–4.94 MPa following fixation for basal chordae; 2.60–2.97 MPa before fixation and 2.31–2.93 MPa following fixation for strut chordae.ConclusionThe viscoelastic properties of mitral valve chordae are affected by glutaraldehyde fixation; in particular, the reduction in storage moduli decreased with an increase in chordal diameter.

Towards viscoelastic characterisation of the human ulnar nerve: An early assessment using embalmed cadavers

“…While much of this range of frequencies may not appear physiological, characterisation of natural tissues should consider not only physiological rates of loading, but also loading associated with exercise, other daily activities, pathophysiology and/or trauma [23,24,35]. However, loading rates and equivalent frequencies associated with loading of the upper-limb/elbow, and of potential relevance to the ulnar nerve are less well understood than, say, for natural tissues such as for heart valves [35][36][37] or lower limbs [23,38,39]. However, there are upper-limb studies which suggest that frequencies of 20 repeats/min (0.33 Hz) are associated with discomfort levels within a physiological loading range [40], providing a lower range for an experimental loading frequency.…”

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

“…They also found that the chordae from the MV posterior leaflet ruptured at 43% less load and 22% less strain than ones from the MV anterior leaflet. Unique mechanical-morphological findings from other studies on the chordae include: (i) decellularized and glutaraldehyde cross-linked chordae (a method for replacing human chordae with porcine chordae) had a longer fatigue life and a lower creep rate than the native chordae [57], (ii) fatigue-induced micro-cracks in the collagen structures can cause increased creep behaviors [58], and (iii) glutaraldehyde-fixed chordae have decreased storage moduli compared to native structures [59]. It is worthwhile to note that while there are many studies characterizing MV chordae, the information regarding TV chordae mechanics is limited, and future investigations are warranted.…”

“…In our lab, we made a recent contribution to the understanding of MV and TV strut chordae mechanics under a novel uniaxial tensile testing scheme [60]. In this study, we performed mechanical characterizations of the chordae tendineae where the attachment regions were preserved, resulting Unique mechanical-morphological findings from other studies on the chordae include: (i) decellularized and glutaraldehyde cross-linked chordae (a method for replacing human chordae with porcine chordae) had a longer fatigue life and a lower creep rate than the native chordae [57], (ii) fatigue-induced micro-cracks in the collagen structures can cause increased creep behaviors [58], and (iii) glutaraldehyde-fixed chordae have decreased storage moduli compared to native structures [59].…”

Objective Uniaxial Identification of Transition Points in Non-Linear Materials: Sample Application to Porcine Coronary Arteries and the Dependency of Their Pre- and Post-Transitional Moduli with Position

“…Alternatively, they may enable the identification of linear regions (i.e. post-transitional) for more advanced characterisation, such as dynamic viscoelasticity of arteries [21], heart valves [42], and other tissues, replacement materials [43,44] and/or chemically natural tissues [45]. Ahead implementation on a wide range of materials, the authors would suggest that any test data used is consistent with existing recommendations for test data to be suitable for characterisation, e.g.…”