Relative Importance of Aneurysm Diameter and Body Size for Predicting Abdominal Aortic Aneurysm Rupture in Men and Women
What is the relationship between abdominal aortic aneurysm (AAA) size and risk of rupture in men and women?
This retrospective review examined 4,045 patients who underwent AAA repair and who were enrolled in the Vascular Study Group of New England database. Patient gender, aneurysm size, and patient body size were evaluated to identify predictors of elective repair versus ruptured repair of an AAA.
Mean age was 72 ± 9 years for men and 74 ± 8 years for women. Women represented 22% of the overall population undergoing AAA repair; ruptured AAA repair was performed in 9% of men and 2% of women. The proportion of aneurysms <5.5 cm in diameter that were ruptured at the time of repair had a trend to be higher in women as compared to men (17% vs. 10%, p = 0.09). Women had smaller aneurysms at the time of rupture repair as compared to men (p < 0.001), whereas there was no difference between genders in aortic size index in those with ruptured versus nonruptured repair (p = 0.20). The variable most strongly associated with risk of ruptured repair was aneurysm diameter (area under the curve [AUC] 0.82) for men, and aortic size index (aneurysm size/body surface area) for women (AUC 0.81). For men, an increased risk of repair for rupture (vs. elective repair) was observed in those with an aneurysm 6.5-7.4 cm in diameter (odds ratio [OR], 3.9; p < 0.001) or ≥7.5 cm (OR, 11.3; p < 0.001). For women, an increased risk of repair in the setting of rupture was noted for an aortic size index of >3.5-3.9 cm/m2 (OR, 6.4; p = 0.006) or an aortic size index ≥4.0 cm/m2 (OR, 9.5; p = 0.002).
Among patients undergoing AAA repair, aortic diameter was the strongest predictor of rupture at the time of repair for men, whereas aortic size index was the strongest predictor of this for women.
This study finds that a significant proportion of men (10%) and women (17%) with an aortic diameter <5.5 cm had an AAA rupture at the time of repair. It further reports that indexing the aorta size to body surface area is the best predictor of rupture at the time of repair in women, whereas aortic diameter is the best predictor of this in men. Importantly, this study demonstrated that among the 12 women with an AAA <5.5 cm in diameter, the potential use of an aortic size index of >2.5 cm/m2 could have resulted in 10 of these women being candidates for elective repair. These results suggest that incorporation of indexed aortic size may be useful to identify patients at risk of rupture, particularly women. An important limitation of this retrospective registry is that it only examines patients who undergo AAA repair, and further study is needed of a cohort that includes patients not undergoing surgery.
Clinical Topics: Vascular Medicine
Keywords: Body Surface Area, Body Size, Aortic Aneurysm, Abdominal
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