Background Aneurysms of the anterior communicating artery (ACoA) are difficult to treat with coiling or clipping because of the anatomical variation in this region. Flow diversion represents a feasible treatment, but no consensus exists as to which stent deployment technique is more suitable.

Methods All patients with ACoA aneurysms treated with flow diverters between April 2014 and November 2018 were retrospectively analyzed. Aneurysm characteristics, follow-up results, and clinical outcome data were recorded, and a new classification comparing the diameters of both A1 segments is proposed: H1=same diameters; H2=<50% difference in diameters; H3= ≥50% difference; and Y=no A1 segment.

Results We analyzed 30 procedures in 30 patients with ACoA aneurysms, including 16 ruptured aneurysms treated with coiling embolization and 4 previously unruptured aneurysms (two Medina and two Woven EndoBridge devices). Adequate aneurysm occlusion occurred in 86.9%; one patient (3.3%) experienced symptomatic ischemic stroke. The global thromboembolic complications for each group were 17.6% (H1), 25% (H2), and 60% (H3).

Conclusion Flow diversion treatment in this region is safe, feasible, and effective. The most suitable anatomical configuration for flow diverter treatment seems to be the H1 configuration where the ‘I technique’ is suitable (from an A1 segment to the ipsilateral A2). There is a tendency that the H3 configuration is not a good indication for flow diverter treatment. However, further studies are needed to evaluate the feasibility of this anatomical classification and the reproducibility of our findings.