Gender differences in the dissection properties of ascending thoracic aortic aneurysms

OBJECTIVES Presentation, management and outcomes in the aortic dissection (AD) of ascending thoracic aortic aneurysm (ATAA) differ in gender and age. The purpose of this study is to investigate the dissection properties of male and female ATAAs. METHODS Peeling tests were performed to quantitatively determine the delamination strength and dissection energy of 41 fresh ATAA samples (22 males and 19 females) in relatively young (<= 65 years) and elderly (>65 years) patients. The delamination strength of the ATAAs was further correlated with patient ages for males and females. The histological investigation was employed to characterize the dissected morphology. RESULTS For elderly patients, circumferential and longitudinal delamination strengths of the female ATAAs were statistically significantly lower than those of the males (circumferential: 31 +/- 6 vs 42 +/- 6 mN/mm, P < 0.01; longitudinal: 35 +/- 7 vs 49 +/- 10 mN/mm, P = 0.02). No significant differences were found in the delamination strength between males and females for relatively young patients. The circumferential and longitudinal delamination strengths were significantly decreased and strongly correlated with patient ages for females. However, these correlations were not present in males. Dissection routes propagated in the aortic media to create ruptured surfaces for all specimens. Peeling tests of the male ATAAs generate rougher surfaces than females. CONCLUSIONS There is a higher propensity of AD occurrence for the elderly females as compared to males with matched ages. Surgeons should be cognizant of the risk of AD onset later in life, especially in females.