Relative importance of aneurysm diameter and body size for predicting abdominal aortic aneurysm rupture in men and women

Abstract

Objectives Women have been shown to have up to a four-fold higher risk of abdominal aortic aneurysm (AAA) rupture at any given aneurysm diameter compared to men, leading to recommendations to offer repair to women at lower diameter thresholds. Although this higher risk of rupture may simply reflect greater relative aortic dilatation in women who have smaller aortas to begin with, this has never been quantified. Our objective was therefore to quantify the relationship between rupture and aneurysm diameter relative to body size and to determine whether a differential association between aneurysm diameter, body size, and rupture risk exists for men and women. Methods We performed a retrospective review of all patients in the Vascular Study Group of New England (VSGNE) database who underwent endovascular or open AAA repair. Using each patient’s height and weight, body mass index (BMI) and body surface area (BSA) were calculated. Next, indices of each measure of body size (height, weight, BMI, BSA) relative to aneurysm diameter were calculated for each patient. To generate these indices, we divided aneurysm diameter (in cm) by the measure of body size [e.g. aortic size index (ASI) = aneurysm diameter (cm) / BSA (m2)]. Along with other relevant clinical variables, we used these indices to construct different age-adjusted and multivariable-adjusted logistic regression models to determine predictors of ruptured repair vs. elective repair. Models for men and women were developed separately and different models were compared using the area under the curve (AUC). Results We identified 4045 patients who underwent AAA repair (78% male, 53% EVAR). Women had significantly smaller diameter aneurysms, lower BSA, and higher BSA indices than men (Table 1). For men, the variable that increased the odds of rupture the most was aneurysm diameter (AUC = 0.82). Men exhibited an increased rupture risk with increasing aneurysm diameter (<5.5cm: OR 1.0; 5.5–6.4cm: OR 0.9, 95% CI 0.5–1.7, P=.771; 6.5–7.4cm: OR 3.9, 95% CI 1.9–1.0, P<.001; 7.5+ cm: OR 11.3, 95% CI 4.9–25.8, P<.001). In contrast, the variable most predictive of rupture in women was ASI (AUC = 0.81), with higher odds of rupture at higher ASI(ASI >3.5–3.9: OR 6.4, 95% CI 1.7–24.1, P=.006; ASI 4.0+: OR 9.5, 95% CI 2.3–39.4, P=.002). For women, aneurysm diameter was not a significant predictor of rupture after adjusting for ASI. Conclusion Aneurysm diameter indexed to body size is the most important determinant of rupture for women whereas aneurysm diameter alone is most predictive of rupture for men. Women with the largest diameter aneurysms and the smallest body sizes are at the greatest risk of rupture.

Negative association of diabetes with rupture of abdominal aortic aneurysm

“…Of 100 potentially relevant articles screened initially, nine eligible studies 8,[11][12][13][14][15][16][17][18] were identified. Furthermore, two relevant studies 6,7 were added through a manual search.…”

The association between body mass index and abdominal aortic aneurysm growth: a systematic review

“…It has been debated, however, whether BMI is associated with AAA rupture. Although the RESCAN meta-analysis [5] of fi ve studies (including only 80 AAA ruptures) demonstrated a negative association between BMI and AAA rupture, a number of studies [39][40][41] suggest no association. Further investigations are required to elucidate why BMI is not associated with AAA growth despite its trend toward a positive association with AAA presence and to determine whether BMI is associated with AAA rupture.…”

The influence of atmospheric pressure on aortic aneurysm rupture — is the diameter of the aneurysm important?

“…Abdominal aortic aneurysm rupture (AAAR) is one of the major issues in both vascular surgery and vascular disease-related mortality [1,2]. The primary reason for the continued high mortality in AAAR patients is that many of these patients are unaware of the presence of this illness.…”

“…The presence of an abdominal aortic aneurysm (AAA) is often asymptomatic, and its rupture, which is often experienced as abdominal pain or a backache, can be misdiagnosed by both the patient and medical staff, particularly if no previous knowledge of the disease has been reported [2]. According to clinical observations, the risk of an AAAR significantly increases with an increase in the aneurysm's diameter [1]. Among the other factors that potentially can be related to the rupture of an aortic aneurysm, uncontrolled arterial hypertension, smoking and increased age should be considered [1,2].…”

“…According to clinical observations, the risk of an AAAR significantly increases with an increase in the aneurysm's diameter [1]. Among the other factors that potentially can be related to the rupture of an aortic aneurysm, uncontrolled arterial hypertension, smoking and increased age should be considered [1,2]. In recent years, many studies on the aetiology of AAA and on AAAR's pathogenic factors have been performed [3,4].…”