Characterisation and evaluation of tensile properties of fresh left atrial appendage and 3D printed models
Invited conference paper presented and published in conference proceedings


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AbstractBackground: We have used personalised left atrial appendage (LAA) models derived from 3D echocardiography for the fit testing of LAA occluders. The fit tests allowed clinicians and surgeons to identify potential leakage sites, hence the optimal size and orientation of the device. However, these tests performed on static 3D printed LAA models cannot fully describe the genuine dynamic condition in patients, and it is challenging to anticipate the robustness of the occlusion throughout the cardiac cycle without comparing the material properties of the two materials. Characterisation and evaluation of tensile properties of the genuine and 3D printed LAAs were therefore performed to facilitate functional evaluation of the fit test strategies.

Methods: Fresh human LAAs were collected from patients during elective LAA removal surgery, and were preserved in chilled Krebs solution (4oC) until testing in laboratory (n = 5). Coincidentally, LAA models derived from 3D echocardiography were 3D printed (Materialise Mimics, BEL; Objet Connex350, Stratasys, US) (n = 4). The two groups of LAAs were dissected around the orifice and cut into ring sample to avoid slippage and end effect during tensile testing. The preconditioned fresh samples and 3D printed samples were loaded accordingly for vertical uniaxial tensile testing (Kinexus lab+, Malvern, UK), and the tensile data recorded within the strain range of 0-20% (physiological modulus) were compared between the two groups.

Results: Our findings revealed that the physiological moduli of the two materials were not significantly different. At normal maximum circumferential expansion (~15% strain), the moduli of the printed LAAs and fresh LAAs were 0.4627 MPa and 0.5009 MPa respectively.

Conclusion: No significant differences were identified between the tensile properties of the two groups of LAAs within physiological strain range. The 3D printed materials should respond similarly as the LAA wall in patients under physiological loading, therefore occlusion robustness predicted by the fit tests with personalised models are accurate and reliable.
Acceptance Date25/09/2017
All Author(s) ListSteven Fan, Alex PW Lee, Yi-ting Fan, Marco Chow
Name of ConferenceKorean Society of Echocardiography Autumn Scientific Conference 2017
Start Date of Conference25/11/2017
End Date of Conference26/11/2017
Place of ConferenceGrand Walkerhill Hotel Seoul
Country/Region of ConferenceSouth Korea
Year2017
LanguagesEnglish-United Kingdom

Last updated on 2018-24-05 at 13:59