Introduction/Purpose Intracranial aneurysms arising from the A1 segment of the anterior cerebral artery (ACA) are a subset of aneurysms that is difficult to treat. These aneurysms typically arise at an angle in horizontal or vertical orientation from the parent vessel and challenge microcatheter navigation into and stable catheter position within the aneurysm neck. Additionally, these aneurysms are mostly very small which further challenges endovascular treatment.

Materials and Methods We retrospectively reviewed our prospectively maintained neurointerventional database and identified all patients with ACA aneurysms between January 2017 and January 2023. We then further selected those patients in whom the aneurysm arose from the A1 segment of the ACA. Patient characteristics, procedural data and follow-up information was collected.

Results A total of 10 patients (7 females) were identified. Patient age ranged from 36 to 78 years (mean 66 years). One aneurysm was ruptured. None of the unruptured aneurysms was previously treated. Mean aneurysm diameter (largest dimension) was 3.1 mm. Mean aneurysm neck size was 1.9 mm. Aneurysm volume ranged from 4.4 mm³ to 18.8 mm³. All aneurysms were treated with single coil embolization. No assisting devices were used. In all but one case a Headway Duo microcatheter (Microvention) was used. A S-shaped Excelsior SL-10 microcatheter (Stryker) was used in one case. Mean packing density was 21.1% (range 8.1 - 31.7%). No intra- or peri-procedural complications were seen. Most interventions were performed via transfemoral access. One patient died prior to follow-up (unrelated cause of death), 1 patient had significant progression of dementia and was unable to return for follow up and another patient was lost to follow up. Currently, six-month follow-up angiogram was available for 5 patients and showed complete occlusion and near complete occlusion in 2 cases each. One patient was found to have asymptomatic distal migration of the coil into a cortical ACA branch. One year follow up is still anticipated for most patients but 1 patient already showed stable complete occlusion and another patient showed progression from near complete to complete occlusion.

Conclusion A1 ACA aneurysms are a challenging subset of intracranial aneurysms that can be treated successfully with coil embolization in selected patients. Microcatheter steam shaping may be necessary to tailor the catheter to the vessel anatomy.

Disclosures A. Kuhn: None. J. Singh: None. M. Garcia: None. S. Sarid: None. A. Puri: 1; C; NIH, Microvention, Cerenovus, Medtronic Neurovascular and Stryker Neurovascular. 2; C; Medtronic Neurovascular, Stryker NeurovascularBalt, Q’Apel Medical, Cerenovus, Microvention, Imperative Care, Agile, Merit, CereVasc and Arsenal Medical. 4; C; InNeuroCo, Agile, Perfuze, Galaxy and NTI.