Joseph Hicklin

Transcatheter Aortic Valve Replacement (TAVR) is a type of minimally invasive procedure commonly used today in patients dealing with severe aortic stenosis. Although this procedure is making great strides in the biomedical field, some complications occur after implementation that are not yet well understood. Human tissue is unique in the fact that it is viscoelastic, meaning that it displays both viscous and elastic qualities when undergoing deformation. Materials of this nature are dependent on the time and speed to which they are being deformed, therefore studying heart tissue’s viscoelastic properties may give further insight to the issues that are occurring with TAVR, since blood flow is pulsatile and therefore time-dependent. In this study, two separate aortic valve heart tissue samples underwent stress relaxation tests to determine the reduction of internal stress a heart sample experiences over time under continuous load and constant temperature. To perform such tests, the 1 inch cruciform shaped heart samples were speckled with spray paint and deformed at 10% the specimen’s gage length for 5 minutes. From there, the strain was tracked using recorded footage and MATLAB strain tracking code to measure individual strains within the tissue. Overall, the obtained properties can then be replicated with specific silicon bulking agent ratios and used to 3-D print a more accurate heart model.