The Natural History of Splenic Artery Aneurysms: Factors That Predict Aneurysm Growth

Purpose: To examine the natural history of splenic artery aneurysms (SAAs) at a single institution and assess the effect of patient factors and aneurysm characteristics on aneurysm growth. Materials and Methods: This single -center retrospective study included patients with SAAs who underwent serial imaging over 30 years (1990-2020). Data regarding patient demographics and aneurysm characteristics were collected. The variables contributing to aneurysm growth were assessed using nonparametric tests for continuous variables and chi -square test 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 SAAs was 15.8 mm (range, 4.0-50.0 mm). Growth over time was observed in 39% of the aneurysms, whereas the remaining 61% were stable in size. Of aneurysms that increased in size, the median aneurysm growth rate was 0.60 mm/y (range, 0.03-5.00 mm/y). Maximum aneurysm diameter of >2 cm and the presence of >50% mural thrombus were significant positive predictors for aneurysm growth ( P = .020 and P = .022, respectively). Greater than 50% rim calcification was a significant negative predictor for aneurysm growth ( P = .009) in multivariate analysis. Conclusions: A larger baseline SAA size, presence of mural thrombus, and lack of rim calcification are associated with increased aneurysm growth rate.