1. Mechanisms of aortic valve incompetence: finite element modeling of aortic root dilatation 
K.Jane Grande, PhD, Richard P Cochran, MD, Per G Reinhall, PhD, Karyn S Kunzelman, PhD 
The Annals of Thoracic Surgery 
Volume 69, Issue 6, Pages (June 2000)
DOI: /S (00)

2. Fig 1
Application of forces to the root nodes (left) creates aortic root dilatation and results in a central opening in the aortic valve (right).
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3. Fig 2
Pressure loading curves for the aortic root, aortic valve, and the region of the root underneath the valve (the ventricular-aortic septum). Loading was initiated with root ramp pressure and followed by the addition of valve pressure. Although the curves illustrate the entire course of diastolic pressure, the model loading finished at the end of isovolumic relaxation (the maximum transvalvular pressure).
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4. Fig 3
The emergence of an enlarging central deficiency is visible in an overview of models showing stress contours of the aortic root and valve at varying percentages of root dilatation: (A) normal (undilated) model top view; (B) normal side view; (C) 5% dilatation model top view; (D) 5% side view, (E) 15% top view, (F) 15% side view, (G) 30% top view, (H) 30% side view, (I) 50% top view, (J) 50% side view. All model results are shown in the same size scale. Note: the finite element software could not display thickness of valve and root elements in these contour plots. By measuring the distance between the Noduli of Aranti in the three leaflets of the different models, we determined that even though a slight central opening is visible in the 5% and 15% dilatation models, these valves were actually closed. In contrast, in the 30% and 50% dilatation models, these distances were larger than the regional leaflet thicknesses, and therefore the valve was not completely closed (kPa = kilopascal).
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5. Fig 4
Aortic valve regional stress in normal (undilated) and dilated models (∗ = significant difference compared with normal model; att = attachment; coapt = coaptation).
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6. Fig 5
Schematic illustration of altered leaflet stress patterns in the dilatation models compared with the stress pattern in the normal (undilated) root model (∗ = significant difference compared with normal undilated mode; σ = stress; dil = dilatation).
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7. Fig 6
Aortic valve regional strain in normal (undilated) and dilated models (∗ = significant difference compared with normal model; att = attachment; coapt = coaptation).
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8. Fig 7
Schematic illustrations of altered leaflet strain patterns in dilatation models compared with strain pattern in normal (undilated) root model (∗ = significant difference compared with normal model; ε = strain; dil = dilatation).
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9. Fig 8
Aortic root stress (A) and strain (B) in normal (undilated) and dilated models (∗ = significant difference compared with the normal model; kPa = kilopascal).
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10. Fig 9
Cross-sections of the noncoronary sinus wall–valve leaflet functional unit in idiopathic dilatation models. These cross-sections illustrate increasing root diameter and progressive flattening of the closed valve leaflet.
The Annals of Thoracic Surgery  , DOI: ( /S (00) )