Introduction: The safety and efficacy of flow diversion for distal circulation aneurysms of the cerebral vasculature has not been well-evaluated. The objective of this study was to assess the use of flow diversion for aneurysms located beyond the circle of Willis in an international, multi-center cohort. ‘Distal’ was defined at, or beyond, the M1, P2 and A2 segments of the MCA, PCA and ACA, respectively.
Methods: Clinical and radiological records from all patients undergoing flow diversion treatment of distal circulation aneurysms at 3 academic centers (2 US, 1 Europe) from 2014 until 2017 were retrospectively reviewed.
Results: 41 patients (mean age=57.6 years, 29 women) harbouring 41 aneurysms who underwent treatment with either the Pipeline Embolization Device (Medtronic Inc, Dublin, Ireland) or the Flow Redirection Endoluminal Device (Microvention, Tustin, California) were included in these analyses. 32 aneurysms (78%) were located in the anterior circulation and 9 (22) were located in the posterior circulation. With a median follow-up of 7.9 months, complete (100%) and near-complete (90-99%) occlusion was noted in 32 (78%) of aneurysms. Angiographic evidence of side branch or perforator vessel coverage was present in 31 (75.6%) of aneurysms and was associated with failure to occlude at follow-up (P=0.04). All patients had good functional outcomes post-treatment (mRS 0 to 2). There were two cases (4.9%) of perforator vessel stroke and no hemorrhagic complications.
Conclusions: Flow diversion is a safe and effective treatment modality for aneurysms beyond the circle of Willis with occlusion rates comparable to alternative treatments and low morbidity. The clinical significance of flow limitation through covered side branches requires further investigation.
Patient Care: This study suggests flow diversion is a safe and effective alternative, with comparable, if not lower, complication rates in comparison to surgery or alternative endovascular methods for treatment of distal cerebral aneurysms.
Learning Objectives: By the conclusion of this session, participants should be able to:
1) Describe the treatment of aneurysms of the distal cerebral circulation
2)Outline the endovascular management of these aneurysms using flow diversion