Flow diversion for aneurysms beyond the circle of Willis: A preliminary experience

To evaluate the safety and efficacy of flow diversion (FDs) for the aneurysms beyond the circle of Willis.We retrospectively reviewed the prospectively maintained database in our center and enrolled patients with aneurysms beyond the circle of Willis (defined as at or distal to the M1, A2, and P2 segments) that were treated with FDs.Between July 2017 to December 2020, 28 patients with 28 aneurysms met the inclusion criteria and were included in this study, with a median age of 50 years old (IQR, 36-63 years). Thirty FDs, including 5 Pipelines and 25 Tubridge FDs, were deployed. Perioperative complications were noticed in 2 patients (7.1%), while asymptomatic adverse events occurred in another three patients (10.7%). Delayed complications occurred in 3.6% of patients (1/28). All patients received clinical follow-up, with the mortality and long-term morbidity of 0 and 3.6% (1/28), respectively. Angiographic follow-up data were available for 26 patients (92.9%) with an interval of 10 ± 7 months (ranged 2-26 months). Sixteen patients (61.5%) showed complete or nearly complete occlusion of aneurysms (OKM grading scale D and C); 6 cases (23.1%) were revealed incomplete occlusion (OKM grading scale B), and 4 cases (15.4%) remained unchanged (OKM grading scale A). The existence of the perforators derived from aneurysms was associated with a lower occlusion rate (p = 0.032).Flow diversion is reliable in the treatment of distal aneurysms with a high technical success rate and low permanent disability rate. The presence of side branches derived from aneurysms was associated with a lower aneurysm occlusion rate.