Mirror aneurysms of the anterior cerebral artery: distinct clinical profile or just another intracranial aneurysm? A systematic review

BACKGROUND: Anterior cerebral artery (ACA) mirror intracranial aneurysms (IAs) are rare, underreported vascular lesions. This systematic review addresses current evidence on ACA mirror aneurysms by analysing patient demographics, clinical presentation, imaging findings, aneurysm characteristics, treatment strategies and outcomes. METHODS: A PRISMA guided systematic search was conducted in MEDLINE, Scopus and Web of Science. Studies reporting ACA mirror IAs, defined as aneurysms arising symmetrically from the same segment of bilateral intracranial arteries, with demographic, clinical and procedural outcome data were included. RESULTS: Of 234 identified articles, 20 met our inclusion criteria comprising 24 patients Most patients were female (79.2%) with a mean age of 54.6 years. Headache was the most common symptom (66.7%). Aneurysm size was reported in 50% of cases, with right-sided aneurysms being larger (mean 5.8 mm) than left-sided aneurysms (mean 4.3 mm). Surgical clipping was used in 70.8% of patients, endovascular coiling in 20.8%; combined treatment in one case (4.2%), and management was unreported in one case. Patient outcomes were incosistently reported. CONCLUSION: ACA mirror IAs remain a clinically complex pathology; our cohort showed a predominance of middle-aged female patients and smaller aneurysm sizes. Despite no clear link between location and rupture, mortality and disability appear higher than previously reported and surgical clipping was the most common treatment. Larger studies are needed to better define risk factors and optimize management.