Fracture properties of porcine versus human thoracic aortas from tricuspid/bicuspid aortic valve patients via symmetry-constraint Compact Tension testing

Figures

• 

  Fig. 1. Clamp load vs. normalized displacement of the aorta recorded by the symmetry-constraint Compact Tension (symconCT) test. (a-f) Porcine tissue under axial (P-ax) and circumferential (P-circ) loading. Dashed curves refer to outliers. (control: normal aortic tissue, col: collagenase-treated tissue, ela: elastase-treated tissue). (g, h) Human tissue under axial (H-ax) and circumferential (H-circ) loading of the aneurysmatic thoracic aorta; red: aortas with bicuspid aortic valve (BAV); blue: aortas with a tricuspid aortic valve (TAV); black: aortas with a quadricuspid aortic valve (QAV). Dashed curves refer to tests that failed before the specimen has been completely separated.

• 

  Fig. 2. Mean and standard deviation of selective mechanical parameters characterizing porcine (a-c) and human (d-e) aortic tissue as recorded by the symmetry-constraint Compact Tension (symconCT) test. (a, d) Peak load. (b, e) Normalized clamp displacement at peak load. (c, f) Total fracture energy per unit undeformed fracture surface. (P: porcine; H: human; ax: axial loading; circ: circumferential loading; control: normal aortic tissue; col: collagenase-treated tissue, ela: elastase-treated tissue; BAV: Aorta with bicuspic aortic valve; noBAV: Aortas with valve other than BAV. * p-value < 0.05; ** p-value < 0.005).

• 

  Fig. 3. Influence of collagen optical density (OD) and patient age on aortic wall mechanical parameters as recorded by the symmetry-constraint Compact Tension (symconCT) test. (a, b, c) Peak load. (d, e, f) Fracture energy. (g, h, i) Normalized clamp displacement at peak load. Blue dot: Data from TAV patients. Red dot: Data from BAV patients. Black dot: Data from QAV patient. Black lines: analysis of BAV and noBAV cases when merged. The analysis is based on linear mixed-effects modelling (LME) with confidence bounds indicated by dashed lines. The \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}^{2}$$\end{document} is adjusted by the number of fixed effects. (P: porcine; H: human; ax: axial loading; circ: circumferential loading; control: normal aortic tissue; col: collagenase-treated tissue, ela: elastase-treated tissue; BSA: body surface area). Given human data, the p-value refers to the influence of the variable in the x-axis on the y-axis.

• 

  Fig. 4. Change of collagen staining intensity in terms of optical density (OD) with the maximum diameter of the ascending aorta. Blue dot: Data from the thoracic aorta of TAV patients. Red dot: Data from the thoracic aorta of BAV patients. Black dot: Data from QAV patients. BAV and noBAV data are here grouped together. The analysis is based on linear mixed-effects modelling (LME) with confidence bounds indicated by dashed lines. The \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}^{2}$$\end{document} is adjusted by the number of fixed effects. Number of data = 24.

• 

  Fig. 5. Crack patterns in porcine and human aortic tissue subjected to symmetry-constraint Compact Tension (symconCT) tests under axial (first row) and circumferential loading (second row). (P: porcine; H: human; ax: axial loading; circ: circumferential loading; control: normal aortic tissue; col: collagenase-treated tissue, ela: elastase-treated tissue; BAV: aorta with bicuspid aortic valve; TAV: aortas with tricuspid aortic valve).

• 

  Fig. 6. Fracture propagation during the symconCT experiment under axial loading of the TAA human specimens and corresponding Elastica van Gieson staining of representative cross-sections after testing; (a) TAA patient with bicuspid aortic valve (H-ax-BAV); (b) TAA patient with tricuspid aortic valve (H-ax-TAV).

• 

  Fig. 7. Porcine aorta specimen that is mechanically unloaded (a) and loaded (b) in the symmetry-constraint Compact Tension (symconCT) test. (c) Elastica Van Gieson staining on human tissue after symconCT testing.