The natural history of splenic artery aneurysms: factors that predict aneurysmal growth.

PURPOSE: This study examines the natural history of splenic artery aneurysms at a single institution and assesses the effect of patient factors and aneurysm characteristics on aneurysm growth.

MATERIALS AND METHODS: This single-center retrospective study included patients with splenic artery aneurysms that underwent serial imaging over 30 years (1990-2020). Patient demographics and aneurysm characteristics were collected. The variables contributing to aneurysm growth were assessed using non-parametric tests for continuous variables and Chi-square for categorical variables. Multivariable linear regression was performed using aneurysm growth rate as a continuous dependent variable.

RESULTS: A total of 132 patients were included in this study. The median maximum diameter of the splenic artery aneurysms was 15.8 mm (range 4.0 - 50.0 mm). 39% of the aneurysms demonstrated interval growth over time, while the remaining 61% were stable in size. Of aneurysms that increased in size, the median aneurysm growth rate was 0.60 mm/year (range 0.03 - 5.00 mm/year). Maximum aneurysm diameter of >2 cm and the presence of >50% mural thrombus were significant positive predictors for aneurysm growth rate (p=0.020 and p=0.022, respectively). Greater than 50% rim calcification was a significant negative predictor for aneurysm growth rate (p=.009) in multivariate analysis.

CONCLUSION: A larger baseline splenic artery aneurysm size, presence of mural thrombus, and lack of rim calcification are associated with increased aneurysm growth rate.