O-055 Underlying autoimmune disease is associated with smaller aneurysm size at rupture

Abstract

<h3>Introduction</h3> Although the role of inflammation in the development of aneurysms is established, less is known about the development of intracranial aneurysms in the setting of underlying autoimmune disease. The underlying systemic inflammation characteristic of disorders such as systemic lupus erythematosus, rheumatoid arthritis, and Sjogren’s syndrome, may influence the development of intracranial aneurysms through common inflammatory pathways. We hypothesize an association between underlying autoimmune disease and aneurysm growth and rupture. <h3>Materials and Methods</h3> Medical records of patients who underwent cerebral angiography between August 2018 and August 2021 were manually reviewed to identify autoimmune diseases, comorbid conditions, and aneurysm characteristics. Aneurysm sizes and location were recorded based on the angiography report. Autoimmune diseases as defined for this study included are those known to have systemic inflammatory effects on the central nervous system or multiple other organ systems. In the case of hypothyroidism patient charts were carefully reviewed to ensure that only autoimmune hypothyroidism was included in the autoimmune disease group. Statistical analysis was performed using R v4.1.0 (R Foundation for Statistical Computing). A multiple logistic regression model was built in R to determine the effect of multiple of independent variables, including autoimmune disease, on rupture status as a binary outcome. A multiple regression model was also constructed to determine the effect of multiple variables, including autoimmune disease, on size of an aneurysm at the time of rupture. <h3>Results</h3> Chart review identified 194 patients with 273 ruptured and unruptured saccular intracranial aneurysms. There were 31 patients with 44 aneurysms identified as having an autoimmune disease. There were no significant differences in age, sex, smoking status, hypertension, or diabetes between autoimmune and non-autoimmune patients. There was no significant association between autoimmune disease and aneurysmal rupture (p=0.66). Average aneurysm size among patients with autoimmune disease was 5.35 mm compared to 6.38 mm in patients without autoimmune disease (p=0.07). The average size of a ruptured aneurysm was significantly smaller among patients with autoimmune disease compared to patients without autoimmune disease (4.71 mm vs 5.95 mm, p = 0.02). Patients with autoimmune disease also had a lower mean Hunt-Hess score at presentation compared to patients without autoimmune disease (1.78 vs 2.52, p=0.04). The multivariate logistic regression model did not identify any significant association between rupture and autoimmune disease when controlling for other variables (p=0.49). In the multivariate linear regression model autoimmune disease was still significantly associated with a smaller size at rupture (p=0.04) and smoking was associated with a larger size at rupture (p=0.03) when controlling for other variables. <h3>Conclusion</h3> In conclusion, autoimmune disease is associated with a smaller aneurysm size at rupture although it is not associated with rupture itself. This association may be due to inflammatory pathways which are common to autoimmune diseases as well as aneurysm wall development. Although we were unable to identify any association between rupture status and the presence of autoimmune disease, the association between smaller size at rupture and autoimmune disease warrants further studies as autoimmune disease may influence the trajectory of aneurysm development and the decision to treat. <h3>Disclosures</h3> <b>A. Matur:</b> None. <b>A. Yamani:</b> None. <b>M. Robinson:</b> None. <b>M. Smith:</b> None. <b>P. Shirani:</b> None. <b>A. Grossman:</b> None. <b>C. Prestigiacomo:</b> None.