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

Background: Cerebral aneurysm recurrence serves as a significant endpoint for assessing the efficacy of various endovascular treatment strategies. The impact of smoking on outcomes such as aneurysm occlusion, recurrence, and recanalization remains unclear due to conflicting evidence.

Purpose: To systematically evaluate the role of smoking in influencing angiographic outcomes following endovascular treatment of intracranial aneurysms.

Data sources: Comprehensive searches were conducted in PubMed, Embase, Scopus, and Web of Science STUDY SELECTION: This systematic review and meta-analysis followed PRISMA guidelines to identify relevant studies assessing smoking's impact on intracranial aneurysms following endovascular treatment.

Data analysis: Studies were screened, selected, and assessed for risk of bias using appropriate checklists. Data on complete and adequate aneurysm occlusion, and recurrence/recanalization rates were extracted. Random-effects meta-analyses calculated risk ratios (ORs) with 95% confidence intervals (CIs). Heterogeneity was measured using the I² statistic.

Data synthesis: A total of 26 studies, encompassing 6,031 patients, met the inclusion criteria. Smokers had higher rates of complete aneurysm occlusion (RR 1.12, 95% CI 1.06-1.19; p < 0.01). Subgroup analysis revealed that smokers undergoing flow diversion exhibited a higher rate of complete occlusion (RR 1.14, 95% CI 1.07-1.21; p < 0.01). However, for patients undergoing coiling, there was no significant difference in complete occlusion rates between smokers and non-smokers (RR 1.00, 95% CI 0.83- 1.20; p = 0.46). Recurrence/recanalization rates were similar between smokers and non-smokers: RR 1.17, 95% CI 0.93-1.47; p = 0.20, and the rate of aneurysm retreatment did not differ between the smokers and non-smokers: RR 0.82, 95% CI 0.59-1.13; p =0.23.

Limitations: Heterogeneity in definitions of smoking status, variations in follow-up durations, short follow up, retrospective nature of studies.

Conclusions: Smoking status does not significantly impact aneurysm recanalization or retreatment after endovascular repair. However, the impact of smoking on complete occlusion rate might differ based on the type of device used for treatment. Histological and molecular factors may contribute to varied outcomes, highlighting the necessity for further research to understand smoking's role in aneurysm healing. Clinically, patients should be advised about the risks of smoking, though current evidence suggests that smoking cessation may not consistently affect treatment efficacy.

Abbreviations: sAH = subarachnoid hemorrhage; RROC = Raymond-Roy occlusion classification.