Abstract 12426: Effect of Presenting Size on Sex Differences in Ascending Aortic Growth Rate

Introduction: Current guidelines recommend ascending aortic surveillance at 6-24 month intervals regardless of sex. However, emerging evidence suggests that ascending aortic growth is faster in women than men. It is unknown whether this difference is affected by presenting aortic size.

Objective: To characterize aortic growth by sex and presenting size.

Methods: The study population consisted of all adults receiving repeated chest computed tomography and/or magnetic resonance imaging at our institution 1994-2022, excluding type A dissections. A custom text processing algorithm was implemented to extract ascending aortic dimensions from radiology reports. Patient-level aortic growth rates were determined by linear regression. Patient-level growth rates were linearly regressed on the interaction of sex and presenting size <4.5 vs 4.5-4.9/5.0-5.4/≥5.5cm, controlling for presenting age. Surveillance intervals at 6, 12, and 24 months were simulated by linear interpolation at the patient level.

Results: Ascending aortic dimensions were extracted from 7194 scans across 1998 patients (676 [34%] female). Mean (SD) aortic growth was 0.12 (2.0) mm/yr in women and 0.0 (2.0) in men. Excess growth rate in women compared to men was 0.45 mm/yr (95% CI, -0.07 to 0.98, p=0.09) at 4.5-4.9cm, 1.26 mm/yr (0.35-2.17, p=0.007) at 5.0-5.4cm, and 0.83 mm/yr (-0.44 to 2.11, p=0.20) at ≥5.5cm. For surveillance intervals of 6, 12, and 24 months, 25% of women presenting at 4.5-4.9cm would reach 5.5cm after 3, 2, and 1 scan(s), respectively, compared to 11, 6, and 3 scans in men. For presentation at 5.0-5.4cm, 25% of women would reach 5.5cm after one six-month scan, compared to 10, 5, and 3 scan(s) in men for intervals of 6-, 12-, and 24-months.

Conclusions: While others have reported faster aortic growth with larger size overall, we observed this trend only in larger-presenting women compared to larger-presenting men. Our findings suggest a role for sex- and size-specific aortic surveillance.