AUTHOR=Ya Xiaolong , Zhang Chaoqi , Zhang Shuo , Zhang Qian , Cao Yong , Wang Shuo , Zhao Jizong 

TITLE=The Relationship Between Smoking and Delayed Cerebral Ischemia After Intracranial Aneurysm Rupture: A Systematic Review and Meta-Analysis

JOURNAL=Frontiers in Neurology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2021.625087

DOI=10.3389/fneur.2021.625087

ISSN=1664-2295

ABSTRACT=Background: 
Delayed cerebral ischemia (DCI) is a main cause of death and disability after intracranial aneurysm rupture. In recent years, some studies have shown that nicotine as the main ingredient of tobacco, instead of causing cerebral vasospasm, will have promoted cerebral vasodilation. This view has led to a debate about the relationship between smoking and DCI. This study aims to determine the relationship between smoking and DCI.
Methods: 
A systematic literature search was performed according to PRISMA guidelines. The Cochrane Library, Web of Science, PubMed and Embase online databases were searched up to September 2020. All studies related to smoking and DCI were included in the analysis. The R and Revman software was used for data analysis, and random or fixed model analysis was selected according to the degree of heterogeneity. Publication bias was examined by using the Begg_Mazumdar test and contour-enhanced funnel plots with trim method.
Results: 
A total of 8 literatures (12 studies) with 10722 patients were included in this meta-study. There were statistically significant higher rates of DCI in smoking group and non-smoking group (RRtotal= 1.16, 95%CI: 1.05~1.27). After the heterogeneity among cohorts was removed by sensitivity analysis, there was still a statistically significant difference of the incidence of DCI between smoking groups and non-smoking groups (RRtotal= 1.13, 95%CI: 1.07~1.20).
Conclusions: 
Although the effects of nicotine as main component of tobacco are unclear in terms of cerebral vessels, Smoking is still a risk factor for DCI in patients with ruptured aneurysm.