Flow diversion for the treatment of intracranial bifurcation aneurysms: a systematic review and meta-analysis

Background Flow diversion (FD: flow diversion, flow diverter) is an endovascular treatment for many intracranial aneurysm types; however, limited reports have explored the use of FDs in bifurcation aneurysm management. We analyzed the safety and efficacy of FD for the management of intracranial bifurcation aneurysms. Methods A systematic review identified original research articles that used FD for treating intracranial bifurcation aneurysms. Articles with >4 patients that reported outcomes on the use of FDs for the management of bifurcation aneurysms along the anterior communicating artery (AComA), internal carotid artery terminus (ICAt), basilar apex (BA), or middle cerebral artery bifurcation (MCAb) were included. Meta-analysis was performed using a random effects model. Results 19 studies were included with 522 patients harboring 534 bifurcation aneurysms (mean size 9 mm, 78% unruptured). Complete aneurysmal occlusion rate was 68% (95% CI 58.7% to 76.1%, I 2 =67%) at mean angiographic follow-up of 16 months. Subgroup analysis of FD as a standalone treatment estimated a complete occlusion rate of 69% (95% CI 50% to 83%, I 2 =38%). The total complication rate was 22% (95% CI 16.7% to 28.6%, I 2 =51%), largely due to an ischemic complication rate of 16% (95% CI 10.8% to 21.9%, I 2 =55%). The etiologies of ischemic complications were largely due to jailed artery hypoperfusion (47%) and in-stent thrombosis (38%). 7% of patients suffered permanent symptomatic complications (95% CI 4.5% to 9.8%, I 2 =6%). Conclusion FD treatment of bifurcation aneurysms has a modest efficacy and relatively unfavorable safety profile. Proceduralists may consider reserving FD as a treatment option if no other surgical or endovascular therapy is deemed feasible.