Endovascular Treatment of Intracranial Unruptured Aneurysms: A Systematic Review of the Literature on Safety with Emphasis on Subgroup Analyses

Published Online:https://doi.org/10.1148/radiol.12112114

Use of remodeling techniques did not increase the risk of unfavorable outcome, whereas use of flow-diverter devices is associated with a risk of unfavorable outcome that is twice the risk of simple coil placement.

Purpose

To report subgroup analyses of an updated systematic review on endovascular treatment of intracranial unruptured aneurysms (UAs); to compare types of embolic agents, adjunct techniques, and newer devices; and to identify potential risk factors for poor outcomes.

Materials and Methods

Meta-Analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used to prepare this article, and the literature was searched with PubMed and with EMBASE and Cochrane databases. Six eligibility criteria (procedural complications rates; at least 10 patients; saccular, nondissecting UAs; original study published in English or French between January 2003 and July 2011; methodological quality score > 6 [modified Strengthening and Reporting of Observational Studies in Epidemiology criteria]; a study published in a peer-reviewed journal) were used. End points included procedural mortality and unfavorable outcomes (death or modified Rankin Scale, Glasgow Outcome Scale, or World Federation of Neurosurgeons Scale at 1 month scores, all > 2). A fixed-effects model (Mantel-Haenszel) was used for pooled estimates of mortality and unfavorable outcomes; a random-effects model (DerSimonian-Laird) was used in case of heterogeneity.

Results

Ninety-seven studies with 7172 patients (26 studies published July 2008 through July 2011) were included. Sixty-nine (1.8%) of 7034 patients died (fixed-effect weighted average; 99% confidence interval [CI]: 1.4%, 2.4%; Q value, 55.0; I2 = 0%). Unfavorable outcomes, including death, occurred in 4.7% (242 of 6941) of patients (99% CI: 3.8, 5.7; Q value, 128.3; I2 = 26.8%). Patients treated after 2004 had better outcomes (unfavorable outcome, 3.1; 99% CI: 2.4, 4.0) than patients treated during 2001–2003 (unfavorable outcome, 4.7%; 99% CI: 3.6%, 6.1%; P = .01) or in 2000 and before (unfavorable outcome, 5.6%; 99% CI: 4.7%, 6.6%; P < .001). Significantly higher risk was associated with liquid embolic agents (8.1%; 99% CI: 4.7%, 13.7%) versus simple coil placement (4.9%; 99% CI: 3.8%, 6.3%; P = .002). Unfavorable outcomes occurred in 11.5% (99% CI: 4.9%, 24.6%) of patients treated with flow diversion.

Conclusion

Procedure-related poor outcomes occurred (4.7% of patients), risks decreased, and liquid embolic agents and flow diversion were associated with higher risks.

©RSNA, 2012

Supplemental material:http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112114/-/DC1

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Article History

Received October 4, 2011; revision requested November 7; final revision received December 20; accepted January 13, 2012; final version accepted January 18.
Published online: June 2012
Published in print: June 2012