Flow-Diversion Treatment for Unruptured Nonsaccular Intracranial Aneurysms of the Posterior and Distal Anterior Circulation: A Meta-Analysis

BACKGROUND

Treatment management and outcomes of unruptured nonsaccular aneurysms are different compared with their saccular counterparts.

PURPOSE

Our aim was to analyze the outcomes after flow diversion among nonsaccular unruptured lesions.

DATA SOURCES

A systematic search of 3 data bases (2005-2019) was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

STUDY SELECTION

We included studies reporting flow diversion for nonsaccular unruptured aneurysms of the posterior and distal anterior circulations. Anterior circulation lesions were included if located distal to the petrocavernous and supraclinoid ICA (MCA, A1, anterior communicating artery, A2). Giant dolichoectatic holobasilar lesions were excluded because of their poor treatment outcomes.

DATA ANALYSIS

Aneurysm occlusion and complication rates were calculated (random effects meta-analysis).

DATA SYNTHESIS

We included 15 studies (213 aneurysms). The long-term adequate occlusion rate was 85.3% (137/168; 95% CI, 78.2%-92.4%; I² = 42.3%). Treatment-related complications were 17.4% (41/213; 95% CI, 12.45%-22.4%; I² = 0%). Overall, 15% (37/213; 95% CI, 10%-20%; I² = 0%) were ischemic events. Procedure-related morbidity was 8% (20/213; 95% CI, 5%-12%; I² = 0%). Fusiform or dissecting types had comparable adequate occlusion (116/146 = 83%; 95% CI, 74%-92%; I² = 48% versus 33/36 = 89%; 95% CI, 80%-98%; I² = 0%; P = .31) and complication rates (35/162 = 17%; 95% CI, 10%-25%; I² = 24% versus 11/51 = 19%; 95% CI, 10%-31%; I² = 0%; P = .72). Aneurysm size (>10 versus ≤10 mm) was independently associated with a higher rate of complications (OR = 6.6; 95% CI, 1.3-15; P = .02). The rate of ischemic events after discontinuation of the antiplatelet therapy was 5% (5/93; 95% CI, 2%-9%; I² = 0%).

LIMITATIONS

Small and retrospective studies were available for this meta-analysis.

CONCLUSIONS

Unruptured nonsaccular aneurysms located in the posterior and distal anterior circulations can be effectively treated with flow diversion. Nevertheless, treatment-related complications are not negligible, with about 15% ischemic events and 8% morbidity. Larger size (>10 mm) significantly increases the risk of procedure-related adverse events.

Acutely Ruptured Intracranial Aneurysms Treated with Flow-Diverter Stents: A Systematic Review and Meta-Analysis

BACKGROUND

The implantation of flow-diverter stents for the treatment of ruptured intracranial aneurysms required further investigation.

PURPOSE

Our aim was to analyze the outcomes after flow diversion of ruptured intracranial aneurysms.

DATA SOURCES

A systematic search of 3 databases was performed for studies published from 2006 to 2018.

STUDY SELECTION

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies (from 2010 to 2018) reporting acutely ruptured intracranial aneurysms treated with flow diversion.

DATA ANALYSIS

Random-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, rebleeding, and factors influencing the studied outcomes.

DATA SYNTHESIS

We included 20 studies evaluating 223 patients with acutely ruptured intracranial aneurysms treated with flow-diverter stents. Immediate angiographic occlusion was obtained in 32% (29/86; 95% CI, 15.4%-48%; I² = 79.6%) of aneurysms, whereas long-term complete/near-complete aneurysm occlusion was 88.9% (162/189; 95% CI, 84%-93.5%; I² = 20.9%) (mean radiologic follow-up of 9.6 months). The treatment-related complication rate was 17.8% (42/223; 95% CI, 11%-24%; I² = 52.6%). Complications were higher in the posterior circulation (16/72 = 27%; 95% CI, 14%-40%; I² = 66% versus 18/149 = 11.7%; 95% CI, 7%-16%; I² = 0%) (P = .004) and after treatment with multiple stents (14/52 = 26%; 95% CI, 14%-45%; I² = 59%) compared with a single stent (20/141 = 10%; 95% CI, 5%-15%; I² = 0%) (P = .004). Aneurysm rebleeding after treatment was 4% (5/223; 95% CI, 1.8%-7%; I² = 0%) and was higher in the first 72 hours.

LIMITATIONS

Small and retrospective series.

CONCLUSIONS

Flow-diversion treatment of ruptured intracranial aneurysms yields a high rate of long-term angiographic occlusion with a relatively low rate of aneurysm rebleeding. However, treatment is associated with a complication rate of 18%. When coiling or microsurgical clipping are not feasible strategies, anterior circulation ruptured aneurysms can be effectively treated with a flow-diversion technique, minimizing the number of stents deployed. Given the 27% rate of complications, flow diversion for ruptured posterior circulation aneurysms should be considered only in selected cases not amenable to other treatments.