Treatment of Middle Cerebral Artery Aneurysms with Flow-Diverter Stents: A Systematic Review and Meta-Analysis of 1036 Aneurysms.

The pooled complete or near-complete occlusion rate for flow diversion of MCA aneurysms was 71% at a mean follow-up of 15 months.

• Analysis encompassed 33 studies and 1,036 MCA aneurysms, representing the largest cohort to date.
• Pooled estimates with 95% confidence intervals were calculated using a random-effects model.
• Mean follow-up duration was 15 months.
• Occlusion rates did not differ significantly across MCA segments: 66% proximal, 69% bifurcation, and 70% distal.

No significant differences in occlusion rates were found across MCA segments or across device types.

• Proximal MCA segment occlusion rate was 66%.
• Bifurcation MCA segment occlusion rate was 69%.
• Distal MCA segment occlusion rate was 70%.
• Subgroup analyses were performed by both aneurysm location and device type with no significant differences identified.

The overall complication rate following flow diversion for MCA aneurysms was 13%, predominantly thromboembolic.

• Complications were predominantly thromboembolic in nature.
• Procedural mortality was 1%.
• The complication rate was derived from pooled analysis of 33 studies covering 1,036 aneurysms.
• Publication bias and underreporting of complications cannot be excluded, which may affect the true complication rate.

Functional independence, defined as modified Rankin Scale (mRS) score of 0–2, was achieved in 90% of patients following flow diversion for MCA aneurysms.

• Functional independence was measured using the modified Rankin Scale (mRS), with scores 0–2 indicating functional independence.
• The 90% functional independence rate was derived from pooled analysis across 33 included studies.
• Included studies were predominantly retrospective cohort series and case series.
• Heterogeneity existed across studies in device type, antiplatelet regimens, follow-up duration, and outcome definitions.

The systematic review identified significant methodological heterogeneity and potential biases across the included studies.

• Included studies were predominantly retrospective cohort series and case series.
• Heterogeneity was noted in device type, antiplatelet regimens, follow-up duration, and outcome definitions.
• Publication bias and underreporting of complications cannot be excluded.
• The study was conducted in accordance with PRISMA guidelines, with inclusion criteria requiring studies of ≥3 patients treated with flow-diverter devices.

Flow diversion for MCA aneurysms remains controversial due to frequent involvement of side branches and bifurcations.

• MCA aneurysms frequently involve side branches and bifurcations, complicating the use of flow-diverter devices.
• Prior to this meta-analysis, outcomes had been reported only in cohort studies and case series, leaving safety and efficacy uncertain.
• The authors note this study represents 'the largest cohort to date' with 1,036 aneurysms across 33 studies.
• The findings 'may support its consideration in carefully selected cases.'