Authors: Alexandra Santos; Jefferson Rosi Júnior, MD, PhD; Saul Almeida da Silva, MD; Ricardo Iglesio, MD; José Guilherme Caldas, MD, PhD; Manoel Teixeira, MD, PhD; Eberval Figueiredo, MD, PhD (Sao Paulo, Brazil)


Multiple intracranial aneurysms represents 30% of all unruptured intracranial aneurysms, and have been associated with cerebrovascular disorder, familiar history, and previous subarachnoid hemorrhage. Here, we investigated the incidence and risk factors associated with multiple intracranial aneurysms.


1404 patients, admitted in Hospital das Clínicas de São Paulo, Brazil, between September 2009 and August 2018, enrolled this study. There were 314 male (22.4%) and 1090 female (77.6%). Diagnosis was performed with digital subtraction angiography. Multiplicity was defined as 2 or more intracranial aneurysms. Individuals characteristics such as sex, age, smoking and hypertension were evaluated. 

512 patients (36.4%) were diagnosed with multiple intracranial aneurysms, accounting for 1362 aneurysms. There was an increased frequency of females with multiple aneurysms (p < 0.001, OR= 1.883, 95% CI= 1.386-2.560). Smoking was associated with multiple aneurysms development, as well as advanced age (p= 0.001, OR= 1.458, 95% CI= 1.160-1.833, and p < 0.001, OR= 1.938, 95% CI= 1.438-2.611, respectively). We observed no significant associations concerning hypertension (p= 0.702). Sorting by size, 60.6% had a diameter between 3-10 mm. We observed higher incidence of baby aneurysms (less than 3 mm) in the group of patients with multiple aneurysms, while giant aneurysms (more than 25 mm) were most found in the group of patients with only one aneurysm (p < 0.001).


Risk factors to the development of intracranial aneurysms, such as sex, advanced age and smoking, were most found in patients with multiple aneurysms when compared with individuals with only one aneurysm.