Introduction: The etiology of intracranial aneurysms remains to be identified. Potential risk factors associated with multiple aneurysms may shed light on the possible cause of aneurysm formation in the first place. (1) In this study, investigators compared patients who underwent microsurgical clipping to see what factors are associated with patients having multiple aneurysms pre-operatively discovered on imaging.

Methods: Solitary aneurysms microsurgically treated by the senior author (M.T.L.) were included from a database of patients treated between January 2010 to April 2013 at a tertiary academic medical center. Patient age, sex, history for hypertension, tobacco use, alcohol use, aneurysm location (anterior vs. posterior), subarachnoid hemorrhage at presentation, aneurysms size, and post-operative neurologic status were collected. Neurologic status was assessed using the modified Rankin Scale (mRS). Neurologic outcomes were dichotomized, categorizing mRS scores 0-2 as ‘good’ and 3-6 as ‘poor’ and aneurysm size into small (<10 mm) or large (= 10 mm).

Results: A total 353 patients were included; 74.8% were female. Patients with multiple aneurysms present comprised 16.7% (59/353) of the population. We found no difference in patients with multiple aneurysms between gender type (p-value=.20), age (p-value=.26), patients = 50 (p-value=.67), history of hypertension (p-value=.12), tobacco use (p-value=.68), alcohol use (p-value=.13), location (p-value=.28), SAH at presentation (p-value=.87), and outcomes (p-value=.45). Patients with large aneurysms did have a greater occurrence of multiple aneurysms (29%, 20/69) than patients with small aneurysms (15.4%, 38/246) (RR 1.88 p-value=.01; 95% CI 1.17 – 3). Using multivariate logistic regression, including age, gender, hypertension, tobacco history, alcohol use, SAH at presentation, location, and size, only size was significant (OR 2.38, p-value=.02; 95% CI 1.16 – 4.85).

Conclusions: Large aneurysms were found to be a risk factor for patients having multiple aneurysms who underwent microsurgical treatment; almost a third had multiple aneurysms present. Patient age, gender, history of hypertension, diabetes, tobacco use, tobacco pack-year history, aneurysm location, SAH presentation, and outcomes were not found to be significant risk factors.

Patient Care: Not only does this research suggest patients with aneurysms ≥10 mm may represent a unique population predisposed to aneurysm formation, it provides a tool for identifying patients who are at high risk in having multiple cerebral aneurysms, thus increasing health care provider suspicion and prompting further work-up when needed.

Learning Objectives: By the conclusion of this session, participants should be able to 1) identify risk factors associated with patients having multiple aneurysms.

References: 1. Juvela S. Risk factors for multiple intracranial aneurysms. Stroke. 2000;31(2):392-7.