Influence of sex on the results of abdominal aortic aneurysm repair. Canadian Society for Vascular Surgery Aneurysm Study Group.

PURPOSE: The purpose of this study is to determine the effect of sex on the survival rate and complications after repair of nonruptured and ruptured abdominal aortic aneurysms (AAA).
METHODS: The Canadian Society for Vascular Surgery Aneurysm Registry formed the database for analysis and provided current, ongoing follow-up of the patients. Statistical methods included t tests, chi-squared analysis, Kaplan-Meier analysis, and Cox regression analysis.
RESULTS: Of the 679 patients undergoing repair of a nonruptured AAA, 19.7% were women and 82.3% men. The following risk factors were significantly different (p < 0.05) in women and men: women were older; more had never smoked; more had a positive family history of AAA; fewer had an electrocardiogram showing evidence of an old myocardial infarction; more had coexisting aortoiliac occlusive disease; fewer had popliteal or femoral aneurysms; and the average size of the AAA was smaller. In spite of potential differences in risk, the in-hospital mortality rates were not affected by sex: 5.2% mortality rate for women and 4.4% for men. Early and late vascular complications occurred with a similar prevalence. The late survival rates were not different in women and men: for women, the 1-, 3-, and 5-year cumulative survival rates were 93.0%, 74.2%, and 63.3%, respectively, and for men 90.3%, 82.8%, and 68.9%. To control for the potential effects of other confounding variables on survival, the Cox proportional hazards method was used. When sex was included in a model along with other significant predictive variables of late survival, sex was not found to be a significant predictor of late results. Of the 146 patients with a ruptured AAA, 13.7% were women and 83.3% men. The in-hospital mortality rates were not significantly different: 55.0% for women and 49.2% for men. There was no difference between the cumulative survival rates: the 3- and 5-year survival rates for women were 36.0% and 9.0%, respectively, and for men 33.9% and 26.9%.
CONCLUSIONS: Sex was not found to have an effect on the early or late results after repair of nonruptured or ruptured AAA. However, a literature review suggests the possibility of a gender bias in the diagnosis and/or selection of patients for surgical treatment because the proportion of women in surgical series is generally less than the proportion determined from autopsy studies, ultrasound studies, hospital discharge data, and national mortality information.