Impact of Tissue Freezing on the Functional and Biomechanical Characteristics of Porcine Aortic Roots

Figures

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  Fig. 1. Representative engineering stress-strain curve illustrating the nonlinear response and the basis for modulus extraction. Secant lines illustrate the high-range tangent modulus (high-strain region prior to failure) and, for STJ specimens, the low-strain tangent modulus, prior to the transition to the steeper high-strain region

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  Fig. 2. Pulsatile left-heart flow-loop model for in vitro testing of porcine aortic roots, shown in A front view and B side view

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  Fig. 3. Boxplots illustrating uniaxial tensile testing of the aortic wall at the sinotubular junction in fresh and thawed porcine aortic roots. A High-range elastic modulus. B Low-range elastic modulus. Boxplots show the median (centre line), interquartile range (box), and whiskers extending to 1.5 × IQR

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  Fig. 4. Boxplots illustrating uniaxial tensile testing of the aortic wall at the sinotubular junction in fresh and thawed porcine aortic roots. A Maximum stress. B Stiffness. C Maximum load. No statistically significant differences were observed between fresh and thawed specimens for any parameter (maximum stress: p = 0.64; stiffness: p = 0.73; maximum load: p = 0.67). Boxplots show the median (centre line), interquartile range (box), and whiskers extending to 1.5 × IQR. p-values are from Welch’s t-test; Mann–Whitney U was performed as a non-parametric sensitivity analysis

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  Fig. 5. Boxplots illustrating uniaxial tensile test results at the non-coronary cusp in fresh and thawed porcine aortic roots. A High-range elastic modulus. B Stiffness. C Maximum load. D Maximum stress. No statistically significant differences were observed between fresh and thawed specimens for any parameter (elastic modulus: p = 0.42; stiffness: p = 0.37; maximum load: p = 0.63; maximum stress: p = 0.47). Boxplots show the median (centre line), interquartile range (box), and whiskers extending to 1.5 × IQR. p-values are from Welch’s t-test; Mann–Whitney U was performed as a non-parametric sensitivity analysis

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  Fig. 6. Fluid dynamic performance of fresh and thawed porcine aortic roots. A Individual paired measurements of mean aortic root pressure gradient in fresh and thawed specimens. B Boxplot summarizing the distribution of mean aortic root pressure gradient across groups. C Individual paired measurements of regurgitant fraction in fresh and thawed specimens. D Boxplot summarizing the distribution of regurgitant fraction across groups. No statistically significant differences were observed (pressure gradient: p = 0.25; regurgitant fraction: p = 0.997). Boxplots show the median (centre line), interquartile range (box), and whiskers extending to 1.5 × IQR. p-values are from paired t-tests

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  Fig. 7. Ultrasonographic measurements in fresh and thawed porcine aortic roots. A Individual paired measurements of annular diameter in systole. B Boxplot summarizing the distribution of annular diameter in systole. C Individual paired measurements of annular diameter in diastole. D Boxplot summarizing the distribution of annular diameter in diastole. E Individual paired measurements of coaptation length. F Boxplot summarizing the distribution of coaptation length. Freeze-thawing did not result in statistically significant changes in any parameter (systolic diameter: p = 0.34; diastolic diameter: p = 0.30; coaptation length: p = 0.14). Boxplots show the median (centre line), interquartile range (box), and whiskers extending to 1.5 × IQR. p-values are from paired t-tests