Increased Virulence of Descending Thoracic and Thoracoabdominal Aortic Aneurysms in Women

Background: This study evaluates sex differences in the natural history of descending thoracic and thoracoabdominal aortic aneurysms (DTTAAs). Methods: In all, 907 patients with descending thoracic and thoracoabdominal aortic sizes greater than 3 cm were retrospectively reviewed. Growth rate estimates were performed utilizing an instrumental variables approach. Yearly complication rates as a function of aortic size were computed. Results: There were 615 men (67.8%) and 292 women (32.2%) treated between 1990 and 2018, with mean aortic diameters of 4.1 ± 1.4 cm and 4.8 ± 1.6 cm, respectively (P <.001). The mean growth rate of DTTAAs was 0.17 cm per year in men and 0.25 cm per year in women (P <.001), increasing with increasing aneurysm size. Dissection, rupture, or aortic death or the combination of the three occurred at double the rate for women compared with men (5.8% vs 2.3% per year for the combined endpoint). Diameter of DTTAA greater than 5 cm was associated with 26.3% (male) and 33.1% (female) average yearly rates of the composite endpoint of rupture, dissection, and death (P <.05). The probability of fatal complications (rupture and death) increased sharply at 5.75 cm in both sexes. Between 4.5 and 5.75 cm, there was another hinge-point of higher probability of fatal complications among women. Conclusions: Women diagnosed with DTTAA fare worse. Faster aneurysm growth and higher rates of dissection, rupture, and aortic death are apparent among women. Current guidelines recommend surgical intervention at 5.5 to 6 cm for DTTAAs without sex considerations. Our findings suggest that increased virulence of DTTAA in women may indicate surgery at a somewhat smaller diameter.