Background Very small aneurysms (VSAs) or microaneurysms are classified as having a maximum dimension of ≤3mm. They are a challenging subset for endovascular treatment. Their small size makes coil embolization treacherous. Herein we aim to evaluate the safety and efficacy of coil embolization of VSA at a major academic center.

Methods A retrospective study of VSAs treated between September 2017 and February 2021 was performed. Aneurysms treated with coil embolization were included. Patient charts were reviewed for clinical and angiographic data. Information about coils was compiled. Descriptive statistics were used to document the results.

Results A total of 57 VSAs were treated among 55 patients. Coil embolization was performed in 32 VSAs (56.1%). 62.5% of these were ruptured. Ultra-soft coils were used for all coiling procedures. Intraoperative rupture (IOR) occurred in 3.1% (1/32). The mortality rate was 6.2%. The immediate adequate occlusion rate was 87.5% of coiled VSA. The retreatment rate was 18.7% at a mean of 153 days. Good functional outcome (mRS 0-2) resulted in 85.9% of subjects.

Conclusion Coil embolization continues to be important and safe in the contemporary management of very small intracranial aneurysms, especially in the setting of ruptured aneurysms.

Disclosures M. Sattur: None. M. Mahdi Sowlat: None. S. Samir Elawady: None. B. Saway: None. S. Al Kasab: None. A. M Spiotta: None.