Dynamic Viscoelasticity and Surface Properties of Porcine Left Anterior Descending Coronary Arteries

Abstract

The aim of this study was, for the first time, to measure and compare quantitatively the viscoelastic properties and surface roughness of coronary arteries. Porcine left anterior descending coronary arteries were dissected ex vivo. Viscoelastic properties were measured longitudinally using dynamic mechanical analysis, for a range of frequencies from 0.5 to 10 Hz. Surface roughness was calculated following three-dimensional reconstructed of surface images obtained using an optical microscope. Storage modulus ranged from 14.47 to 25.82 MPa, and was found to be frequency-dependent, decreasing as the frequency increased. Storage was greater than the loss modulus, with the latter found to be frequency-independent with a mean value of 2.10 ± 0.33 MPa. The circumferential surface roughness was significantly greater (p < 0.05) than the longitudinal surface roughness, ranging from 0.73 to 2.83 and 0.35 to 0.92 µm, respectively. However, if surface roughness values were corrected for shrinkage during processing, circumferential and longitudinal surface roughness were not significantly different (1.04 ± 0.47, 0.89 ± 0.27 µm, respectively; p > 0.05). No correlation was found between the viscoelastic properties and surface roughness. It is feasible to quantitatively measure the viscoelastic properties of coronary arteries and the roughness of their endothelial surface.

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

“…ElectroForce 3200 testing machine running Bose WinTest 4.1 DMA software (Bose Corporation, ElectroForce Systems Group, Minnesota, USA). DMA has previously been used to quantify the storage and loss properties of a variety of biological tissues[22,[25][26][27][28] and orthopaedic implants…”

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.…”

“…A limitation of this study is that samples have undergone freeze-thaw cycles. Briefly, while freeze-thaw cycles might influence tissue mechanics to some extent, it is the method of freezing which is critical [37,38,39]; as discussed elsewhere in more detail [21].…”

“…tested axially), consistent with the longitudinal displacement of the left coronary artery [19,20] which ranges from 0.5 mm to 6.5 mm for the LAD [19]. Specimens were not tested to failure, as specimens were also used as part of a separate study [21]. Force-displacement data from the tenth, and final, cycle was used to calculate the pre-and post-transitional moduli ( Figure 2).…”

Zirconia implants with improved attachment to the gingival tissue

“…Soft tissues, including the gingival tissue, and the attachment apparatus formed between them and a dental implant abutment, are viscoelastic in nature. [43][44][45] A viscoelastic material is a material that exhibits both elastic and viscous characteristics, i.e., its behavior contains both elastic and dissipative components of deformation. 46,47 Elastic materials deform under stress and return to their original state when the stress is removed, while viscous materials return over time to a state similar, but not identical, to the original state.…”