Overlapping Flow Diverter with Coiling for Fetal-type Posterior Communicating Artery Aneurysms with Triple Antithrombotic Therapy: A Case Series

Flow diverters have revolutionized the treatment of large and giant cerebral aneurysms. However, aneurysms with branch vessels originating from the aneurysm sac remain challenging for flow diverter monotherapy. We present five cases demonstrating favorable outcomes following combined treatment with overlapping flow diverter with coiling. The study cohort included five female patients with a mean age of 72.8 years. The mean aneurysm diameter was 8.1 mm. Triple antithrombotic therapy (dual antiplatelet therapy plus short-term anticoagulation) was administered to prevent ischemic complications due to posterior communicating artery occlusion in the perioperative period. Complete or near-complete occlusion (O'Kelly-Marotta grade C or D) was achieved in all cases. Follow-up angiography (mean follow-up time: 17.2 months) revealed preserved patency of the posterior communicating artery in four of five cases. In one case, the posterior communicating artery arising from the aneurysm was occluded at its origin but was supplied retrograde from the posterior circulation. Follow-up digital subtraction angiography of most cases showed caliber changes, with the posterior communicating artery diameter reducing and the P1 segment of the posterior cerebral artery increasing. No ischemic or hemorrhagic complications occurred perioperatively or during follow-up. Overlapping flow diverter with coiling combined with low-dose and short-term triple antithrombotic therapy might be a safe and effective treatment for fetal-type posterior communicating artery aneurysms, offering a viable alternative for complex aneurysms. Further studies with long-term follow-up data from a larger patient cohort are required to validate the efficacy and safety demonstrated in this case series.