Impact of Smoking on Recurrence and Angiographic Outcomes after Endovascular Treatment of Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND: Cerebral aneurysm recurrence remains a critical endpoint in evaluating the success of endovascular treatment. While smoking is a recognized risk factor for aneurysm formation and rupture, its impact on post-treatment angiographic outcomes is unclear due to conflicting evidence.

PURPOSE: To systematically assess the association between smoking and angiographic outcomes—including occlusion, recurrence, and retreatment—following endovascular treatment of intracranial aneurysms.

DATA SOURCES: A comprehensive search of PubMed, Embase, Scopus, and Web of Science was conducted from inception to June 25, 2024. Bibliographies of included studies were also screened.

STUDY SELECTION: Studies were eligible if they involved adult patients with intracranial aneurysms treated via endovascular approaches and reported outcomes stratified by smoking status. Case reports, abstracts, and studies not reporting smoking data were excluded.

DATA ANALYSIS: Risk of bias was assessed using the Newcastle-Ottawa Scale. Random-effects meta-analyses were conducted using generalized linear mixed models to estimate risk ratios (RRs) with 95% confidence intervals (CIs). Subgroup, sensitivity, and meta-regression analyses were also performed.

DATA SYNTHESIS: Twenty-five studies involving 5,828 patients were included. Smokers had a higher rate of complete aneurysm occlusion (RR 1.12, 95% CI 1.06–1.19; P < .01), especially among those undergoing flow diversion (RR 1.14, 95% CI 1.07–1.21; P < .01). No significant differences were found in recurrence/recanalization rates (RR 1.20, 95% CI 0.91–1.60; P = .20) or retreatment rates (RR 0.81, 95% CI 0.58–1.13; P = .22) between smokers and non-smokers. Heterogeneity was moderate to high for some outcomes but reduced after sensitivity analyses.

LIMITATIONS: Heterogeneity in smoking definitions, variable follow-up durations, reliance on retrospective data, and limited granularity on smoking intensity (eg, pack-years) may affect interpretation. Results are not generalizable to surgical clipping or long-term outcomes.

CONCLUSIONS: Smoking is associated with increased complete occlusion rates following flow diversion, but does not significantly impact recurrence or retreatment rates. While smoking cessation remains essential for vascular health, its influence on endovascular treatment efficacy may be limited. Standardized reporting and further mechanistic studies are needed to elucidate smoking’s role in aneurysm healing.