Safety and Efficacy of Flow Diverter Treatment for Aneurysm in Small Cerebral Vessels: A Systematic Review and Meta-Analysis

Purpose: To clarify the safety and efficacy of flow diverter (FD) treatment for aneurysm in small cerebral vessels, we conducted a systematic review of the literature analyzing perioperative and long-term clinical and angiographic outcomes.

Methods: A comprehensive review of the up-to-date literature for studies with ≥10 patients related to FD treatment of small vessel aneurysms published was performed. Random-effects meta-analysis was used to pool the following outcomes: complete occlusion, technical procedural success, perioperative mortality, perioperative stroke, procedure-related morbidity and mortality, all complications, long-term mortality, and overall good outcome.

Results: We included 26 noncomparative studies with 572 target aneurysms. The technical procedural success rate was 96% (95% confidence interval [CI] 0.93-1.00). At final follow-up, the complete occlusion rate was 70% (95% CI 0.64-0.76). The all-cause morbidity rate was 20% (95% CI 0.14-0.25). Procedure-related morbidity and mortality rates were 9% (95% CI 0.07-0.12) and 4% (95% CI 0.00-0.08), respectively. Overall long-term good outcome rate was 96% (95% CI 0.93-0.99). In the 3 subgroup analyses, complete occlusion rate of saccular aneurysms was lower than that of nonsaccular aneurysms (55% vs. 73%, respectively; odds ratio 0.40, 95% CI 0.17-0.98, P = 0.04). The procedure-related morbidity rate and the good outcome rate were not significantly different in this subgroup. In the other 2 subgroups in which we compared anterior circulation aneurysms with posterior circulation aneurysms and single FD strategy with overlapped FD strategy, the rates were also not significantly different.

Conclusions: Our meta-analysis demonstrated that FD treatment of small vessel aneurysms is technically feasible and effective with a high rate of complete occlusion. Although the comorbidities of patients cannot be neglected, the FD approach was associated with an acceptable rate of procedure-related morbidity and a satisfactory rate of overall good outcome.