Evaluating Growth Patterns of Abdominal Aortic Aneurysms Among Women

Objectives Though initially protected from vessel dilation by estrogen, women may experience rapid abdominal aortic aneurysm (AAA) growth post-menopause. The rate of growth has been poorly defined in prior literature. Here we describe aneurysm growth in a cohort of women found through an AAA screening program. Methods Women with AAA were retrospectively identified. Aortic imaging was reviewed, and measurements of maximum transverse and anterior-posterior diameters were completed. Growth was stratified by the type of aortic pathology (fusiform aneurysm, aortic ectasia, dissection with aneurysmal degeneration, saccular aneurysm) as well as size category (<3 cm, 3.0-3.9cm, 4.0-4.9cm, ≥5.0cm) at diagnosis. Results A cohort of 488 women was identified; 286 had multiple scans for review. The mean age of the entire cohort was 75 (±9.9) years old. Stratified by type of pathology, the mean age was 76 (±8.9) in patients with a fusiform AAA, 74 (±9.8) in ectasia, 65 (±13.7) in dissection, and 76 (±5.6) in saccular aneurysms. The maximum growth was highest in women with fusiform AAAs, followed by dissection, ectasia, and saccular pathology (9.7mm, 7.0mm, 3.0mm, 2.2mm, respectively, p<.001). Comparing mean growth by year, the highest mean growth was in fusiform AAAs (3.6mm vs 1.75mm in dissection, p<.001). Shapiro Wilk test demonstrated that mean growth per year was non-normally distributed with a right skew. Stratified by aortic diameter at the time of diagnosis, mean growth/year increased with increasing size at diagnosis in fusiform AAA and dissection (0.91mm for <3cm, 2.34mm for 3.0-3.9cm, 2.49mm for 4.0-4.9mm, and 6.16mm for ≥5.0cm in patients with fusiform aneurysms versus 0.57mm, 0.94mm, 1.87mm 2.66mmm, respectively for patients with dissection). Smoking history was associated with a higher mean growth/year (2.6mm vs 3.3mm, p <.001). Conversely, patients with a family history of AAA had a lower mean growth/year (3.2mm vs 1.5mm, <.001). Conclusions The rate of aneurysm growth in women varies based on pathology and aneurysm size, and women experience rapid aneurysm growth at sizes greater than 4.5 centimeters. Current screening guidelines are inadequate, and our results demonstrate that the rate of growth of fusiform aneurysms in women is faster than in men at a smaller size and may warrant more frequent surveillance than current SVS recommendations to prevent risk of increased morbidity.