PSI - Issue 10

I.D. Gavardinas et al. / Procedia Structural Integrity 10 (2018) 18–24 I.D. Gavardinas and A.E. Giannakopoulos / Structural Integrity Procedia 00 (2018) 000 – 000

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mm respectively. An observation reveals that the first sample is less susceptible to indentation. These results would be difficult to measure with conventional indentation procedures.

Table 1. Results for the indentation of two commercial bovine pericardium vascular patches. Measured Property Material Bovine patch 1 Bovine patch 2 Rubber t (mm) 1.8 1.8 2.0 H M (average) 69.40 62.90 79.67 P(N) 0.6294 0.60076 0.6745 h (mm) 3.828 4.641 2.542 h/b 3.959 4.801 2.631 Analysis Bovine Patch 1 Bovine patch 2 Rubber ν (assumed) 0.5 0.5 0.5 E (MPa ) 6.356 4.701 11.373

Bearing into mind that in the final steps of CEA the patch is sutured on the artery with the use of appropriate needles and sutures, these properties could be connected with the resistance to bleeding or tearing caused by the procedure itself, and therefore taken into account for material selection for CEA. Blood-proofness in the post operative phase is vit al for the patient’s condition; see for instance Muto et al. (2009) and Marien et al. (2002). One may observe that there is a variation in the mechanical properties of materials which are initially conceived as similar. In our case, the bovine materials ’ elastic moduli differ by almost 26%. This could be attributed to differ ences in microstructure and the lack of guidelines on harvesting the bovine tissue from the pericardial sac. For further consideration on the subject, the interested reader is referred to Gavardinas et al. (2018). Our approach follows closely pertinent analytic solutions, requiring solely one experimental input, rendering these methodologies a powerful, easy to implement tool for the mechanical characterization of patches and similar biomaterial systems. It is hoped that the proposed methodology could be further exploited for the mechanical characterization of other biomaterials and contributes to material selection for CEA. The latter remains an open issue that urges for a close synergy among vascular surgeons and engineers.

Acknowledgements

This work was supported by the “Excellency II” (“ARISTEIA II”) Action of the “Operational Programme for Education and Lifelong Learning”, project “Fatigue of Materials used in Vascular Surgery - FaMaVaSu”, conducted by the Greek General Secretariat for Research and Technology (GSRT).

References

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