Sex Differences in Thoracic Aortic Aneurysm Growth: Role of Aortic Stiffness

Women with thoracic aortic aneurysms (TAAs) have higher risk of acute aortic syndromes and death than men. We have shown that TAA growth is accelerated in women, helping explain the sex differences in TAA outcomes. Since aortic stiffness reflects the health of the aorta, we sought to determine the sex-specific role of aortic stiffness on TAA growth. One hundred thirty unoperated people with TAA were recruited. Maximal aneurysm size at the oldest and latest imaging studies was measured to calculate TAA growth rate. Aortic stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV) using applanation tonometry. Multivariable linear regression adjusted for confounders assessed the association of cfPWV with TAA growth. Seventy-three percent of subjects were men. Mean +/- SD age, baseline aneurysm size, follow-up time, and cfPWV were 62.5 +/- 11.5 years, 45.3 +/- 4.0 mm, 3.3 +/- 3.0 years and 9.6 +/- 3.5 m/s, and not different based on sex. TAA growth rate was 0.96 +/- 1.00 mm/y in women and 0.45 +/- 0.58 mm/y in men (P=0.006). In the whole group, cfPWV was independently associated with TAA growth (+/- SE: 0.06 +/- 0.02, P=0.02). However, in sex-specific analyses cfPWV was independently associated with faster aneurysm growth in women (+/- SE: 0.21 +/- 0.09, P=0.03), but not in men (+/- SE: -0.002 +/- 0.02, P=0.94), with a significant sexxcfPWV interaction (P<0.0001). In patients with TAA, aneurysm growth is more than twice as fast in women than men, and aortic stiffness is associated with greater TAA growth in women, but not in men. Our findings highlight greater aortic stiffness as an important correlate of TAA expansion in women.