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

Abstract

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%; I 2 4 42.3%). Treatment-related complications were 17.4% (41/213; 95% CI, 12.45%-22.4%; I 2 4 0%). Overall, 15% (37/213; 95% CI, 10%-20%; I 2 4 0%) were ischemic events. Procedure-related morbidity was 8% (20/213; 95% CI, 5%-12%; I 2 4 0%). Fusiform or dissecting types had comparable adequate occlusion (116/146 4 83%; 95% CI, 74%-92%; I 2 4 48% versus 33/36 4 89%; 95% CI, 80%-98%; I 2 4 0%; P 4 .31) and complication rates (35/162 4 17%; 95% CI, 10%-25%; I 2 4 24% versus 11/51 4 19%; 95% CI, 10%-31%; I 2 4 0%; P 4 .72). Aneurysm size (.10 versus #10 mm) was independently associated with a higher rate of complications (OR 4 6.6; 95% CI, 1.3-15; P 4 .02). The rate of ischemic events after discontinuation of the antiplatelet therapy was 5% (5/93; 95% CI, 2%-9%; I 2 4 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. ABBREVIATIONS: AC 4 anterior circulation; FD 4 flow diversion; IQR 4 interquartile range; PC 4 posterior circulation

Endovascular Treatment of Anterior Circulation Aneurysms With the p64 Flow Modulation Device: Mid- and Long-Term Results in 617 Aneurysms From a Single Center

“… 14 , 22-25 One possible reason is that we did not include aneurysms located in the posterior circulation, which are known to be associated with higher complication rates. 28 , 29 …”

Anterior Circulation Fusiform Aneurysms Have a Lower Occlusion Rate After Pipeline Embolization Device Treatment Than Posterior Circulation Fusiform Aneurysms: A Multicenter Cohort Study

“…Previous reports of intracranial fusiform aneurysms treated with flow diverter devices (FDD) have been based on small series studies, with an overall occlusion rate of 59–100% ( 7 – 10 ). In one meta-analysis of AC fusiform aneurysms located distal to the circle of Willis and PC fusiform aneurysms, Cagnaggo et al reported an occlusion rate of 83% ( 11 ). Monteith et al reported 24 intracranial fusiform aneurysms treated with PEDs, 22 of which were followed up with DSA for an average of 6.3 months, with an occlusion rate of 59% ( 7 ).…”

“…Fusiform intracranial aneurysms are rare, and their unique morphology and pathological development continue to present a challenge for neurosurgical treatment ( 1 – 4 ). While the Pipeline Embolization Device (PED; Medtronic, Minneapolis, MN, USA) provides a treatment option for fusiform aneurysms, few studies have investigated this ( 5 – 10 ), especially in posterior circulation (PC) and anterior circulation (AC) fusiform aneurysms beyond the circle of Willis, for which PED use is off-label ( 11 ). Previous studies on fusiform aneurysms have mostly been single-center studies; the present study included data from multiple centers.…”

Whether Intracranial Aneurysm Could Be Well Treated by Flow Diversion: A Comprehensive Meta-Analysis of Large-Sample Studies including Anterior and Posterior Circulation

“…For the recent meta-analysis, they included data with specific locations or morphologies so that their conclusions explained the specific problem and provided detailed evidence, while the sample size of some of their included studies was <10 [40,44]. Including too many smallsample studies might result in a nonnegligible fluctuation of the results, just as the complete occlusion rate calculated by Kiyofuji et al [44] was 52% (29-76%), while the record from Cagnazzo et al [45] was 85.3% (78.2-92.4%). For unruptured nonsaccular intracranial aneurysms of the posterior circulation, the two studies also showed different outcomes.…”

“…We excluded <100 sample studies, meanwhile losing more individual data published in case series. While Cagnazzo et al [40][41][42]45] and Sorenson et al [43] have made up for this deficiency, they included studies with individual data so that the specific subgroup result could be supported. Finally, the heterogeneity in the HE and IE results was still nonnegligible, even though the results were consistent with most multicenter studies.…”