Figure 4

Gain of medial components in aortic aneurysms. (A) Enlargement of the lumen is associated with thinning of the media and its concentric lamellae assuming preservation of medial area and (B) this relationship is described graphically for radius (a) to medial thickness (b) indices of 10 (typical of nondilated aortas) and 20 (typical of aneurysmal aortas). The derived equation (“Supplementary Appendix”) was applied to quantitative histomorphometry data of ascending aorta specimens from organ donors and patients undergoing aneurysm repair. (C) Luminal enlargement was calculated from observed to expected aortic diameters of aneurysm patients according to published nomograms of healthy subjects. (D) Media thickness, (E) elastic lamella thickness, and (F) interlamellar distance of nondilated aortas and observed and predicted values for aneurysmal aortas. Individual data shown with bars representing mean ± SD, n = 17 nondilated and n = 18 aneurysms, *P < 0.05, ***P < 0.001 aneurysm versus nondilated, Kruskal–Wallis test with Dunn’s multiple comparisons test.