Risk factors for growth of conservatively managed unruptured intracranial aneurysms

Cigarette Smoking and Observed Growth of Unruptured Intracranial Aneurysms: A Systematic Literature Review and Meta-Analysis

BACKGROUND

Smoking and observed growth of intracranial aneurysms are known risk factors for rupture. The mechanism by which smoking increases this risk is not completely elucidated. Furthermore, an association between smoking and aneurysm growth has not been clearly defined in the literature. We hypothesize that smoking is associated with aneurysm growth, which, in turn, may serve as one of the mechanisms by which smoking drives rupture risk.

METHODS

We report a systematic review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Using the R software, we performed a meta-analysis to investigate the association between smoking and the growth of unruptured intracranial aneurysms. Studies on familial aneurysms and genetic syndromes known to increase the risk of aneurysms were excluded.

RESULTS

Eighteen observational studies were included with a total of 3535 patients and 4289 aneurysms with a mean follow-up period ranging from 17 to 226 months. The mean age among the studies ranged from 38.4 to 73.9 years; 74% of patients were female. Ever-smoking status (odds ratio, 1.10 [95% CI, 0.87-1.38]) and current smoking status (odds ratio, 1.43 [95% CI, 0.84-2.43]) did not show a statistically significant association with growth of intracranial aneurysms. Patients currently smoking did not have a statistically significant association with the growth of intracranial aneurysms (odds ratio, 1.18 [95% CI, 0.72-1.93]) compared with patients without a smoking history. No significant association was found in patients who previously smoked compared with patients who never smoked (odds ratio, 1.46 [95% CI, 0.88-2.43]).

CONCLUSIONS

Smoking is not clearly associated with the growth of unruptured intracranial aneurysms, despite trends being observed, there is no statistical association. The mechanism by which smoking increases rupture risk might not be growth. In patients for whom observation is recommended, the absence of growth over time in the setting of smoking history does not, therefore, imply protection from rupture.

Body composition and rupture risk of intracranial aneurysms

BACKGROUND

Rupture of an intracranial aneurysm resulting in a subarachnoid hemorrhage (SAH) is a life-threatening situation. Obesity is an increasing health challenge associated with numerous comorbidities. However, recent studies have shown a surprising decreased risk of SAH with increasing body mass index (BMI). The aim was to explore associations between other anthropometric variables and the rupture risk of an intracranial aneurysm, which to our knowledge is lacking in present literature.

METHODS

Using a bioelectrical impedance analysis device, we performed body composition analyses on 31 patients admitted with aneurysmal SAH (aSAH) and 28 patients with planned intervention on their unruptured aneurysm. We also collected information on comorbidities and relevant risk factors. Logistic regression was used to explore associations between anthropometric variables and patients with ruptured versus unruptured aneurysms.

RESULTS

Unadjusted estimates showed a significant inverse relationship between body fat percent and aneurysmal rupture (OR [95% CI]: 0.92 [0.86, 0.97], P = 0.009), and between body fat mass and aneurysmal rupture (OR [95% CI]: 0.95 [0.90, 0.99], P = 0.047). These risk relationships remained significant in age- and sex-adjusted analyses for body fat percent (OR [95% CI]: 0.93, [0.87, 0.97], P = 0.028), and body fat mass (OR [95% CI]: 0.95 [0.90, 0.99], P = 0.041).

CONCLUSIONS

In recent studies showing a paradoxical relation between aSAH and obesity, BMI was the only parameter investigated. We further explored this "obesity paradox" and found lower body fat in aSAH patients compared to UIA. Future studies should investigate these relationships in larger samples. Clinical Trial Registration NCT04613427, November 3, 2020, retrospectively registered.

Clinical impact of Sim & Size® simulation software in the treatment of patients with cerebral aneurysms with flow-diverter Pipeline stents

OBJECTIVES

This study evaluated the clinical impact of the Sim&Size® simulation software on the endovascular treatment with flow-diverter stents of patients with unruptured saccular intracranial aneurysms.

METHODS

This monocentric retrospective study evaluated a cohort of patients treated with flow-divert stents between June 1, 2014, and December 31, 2019, for cerebral aneurysms. Patients belonged to two groups, patients treated with and without the Sim&Size® simulation software. Univariate, bivariate, and multivariate analyses were used to evaluate the clinical impact of simulation software.

RESULTS

Out of the 73 interventions involving 68 patients analyzed by the study, 76.7% were simulated using the Sim&Size® simulation software, and 23.3% were not. Patients treated with the simulation software had shorter stent lengths (16.00 mm vs. 20.00 mm p-value = 0.001) and surgical time (100.00 min vs. 118.00 min p-value = 0.496). Also, fewer of them required more than one stent (3.6% vs. 17.6% p-value = 0.079). Three patients belonging to the non-stimulated group presented hemorrhagic complications.

CONCLUSIONS

Using the Sim&Size® simulation software for the endovascular treatment of intracranial aneurysms with pipeline flow-diverter stents reduces the stent length.

Prevalence and Risk Factors for Unruptured Intracranial Aneurysms in the Population at High Risk for Aneurysm in the Rural Areas of Tianjin

Although the prevalence of unruptured intracranial aneurysm (UIA) lies between 2 and 5%, the consequences of aneurysm rupture are fatal. The burden of UIA is considerable in stroke patients. However, the best prevention and management strategy for UIA is uncertain among patients with a family history of stroke. Therefore, this study aimed to determine the epidemiological characteristics and risk factors for UIA based on a population with a family history of stroke. This study used random sampling to recruit participants with a family history of stroke among rural residents in Jixian, Tianjin, China. All participants underwent a questionnaire survey, physical examination, and cervical computed tomography angiography (CTA). CTA data were used to determine whether the subjects had UIA. The relationship between relevant factors and UIA was assessed using logistic regression analysis. A total of 281 residents were recruited in this study, with a mean age of 50.9 years. The prevalence of UIA in those with a family history of stroke was 10.3% overall (9.8% among men and 10.9% among women). Moreover, with each unit increase in body mass index (BMI), the prevalence of UIA decreased by 12.5%. Particularly among non-obese men, BMI had a stronger protective effect (OR: 0.672; 95%CI: 0.499–0.906; P = 0.009), and among non-obese men, an increase in low-density lipoprotein (LDL) was associated with an increased prevalence of UIA (OR: 3.638; 95%CI: 1.108–11.947; P = 0.033). Among the non-obese with a family history of stroke, BMI may be protective against UIA, especially in men. It is crucial to strictly control the LDL level in non-obese people to reduce the burden of UIA.

Association Between Body Mass Index and Intracranial Aneurysm Rupture: A Multicenter Retrospective Study

Background and Aims: It has recently emerged the concept of “obesity paradox,” a term used to describe an inverse association between obesity and clinical outcomes in cardiovascular diseases and stroke. The purpose of this study was to investigate the association between body mass index (BMI) and the risk of intracranial aneurysm rupture.

Methods: In this study, we conducted a retrospective analysis of a prospectively maintained database of patients with intracranial aneurysms from 21 medical centers in China. A total of 3,965 patients with 4,632 saccular intracranial aneurysms were enrolled. Patients were separated into unruptured (n = 1,977) and ruptured groups (n = 1,988). Univariable and multivariable logistic regression analyses were performed to determine the association between BMI and intracranial aneurysm rupture.

Results: Compared to the patients with normal BMI (18.5 to < 24.0 kg/m²), the odds of intracranial aneurysm rupture were significantly lower in patients with BMI 24.0 to < 28.0 kg/m² (OR = 0.745, 95% CI = 0.638–0.868, P = 0.000) and patients with BMI ≥ 28.0 kg/m² (OR = 0.628, 95% CI = 0.443–0.890, P = 0.009). Low BMI (<18.0 kg/m²) was not associated with intracranial aneurysm rupture (OR = 0.894, 95% CI = 0.483–1.657, P = 0.505). For males, both the BMI 24.0 to < 28.0 kg/m² (OR = 0.606, 95% CI = 0.469–0.784, P = 0.000) and the BMI ≥ 28.0 kg/m² (OR = 0.384, 95% CI = 0.224–0.658, P = 0.001) were associated with a lower rupture risk, whereas the inverse association was not observed in females. Both the BMI 24.0 to < 28.0 kg/m² (OR = 0.722 for aged 50–60y, 95% CI = 0.554–0.938, P = 0.015; OR = 0.737 for aged >60y, 95% CI = 0.586–0.928, P = 0.009) and the BMI ≥ 28.0 kg/m² (OR = 0.517 for aged 50–60y, 95% CI = 0.281–0.950, P = 0.0034; OR = 0.535 for aged >60y, 95% CI = 0.318–0.899, P = 0.0018) was associated with a lower rupture risk in patients aged ≥50 years, whereas the association was not significant in patients aged <50 years.

Conclusions: Increased BMI is significantly and inversely associated with saccular intracranial aneurysm rupture in males and patients aged ≥50 years.

Management of incidental unruptured intracranial aneurysms

The widespread use of MR has led to the increasingly frequent diagnosis of unruptured incidental intracranial aneurysms. Most are small (<7 mm diameter) and will never rupture. Yet, their recognition causes much anxiety, and their optimal management remains controversial. This review addresses the difficulties in managing incidental unruptured saccular intracranial aneurysms. Note that our conclusions and recommendations do not apply to symptomatic unruptured aneurysms or to fusiform, dissecting, mycotic, traumatic and paediatric aneurysms, each of which has a different natural history.

Weighted gene co-expression network analysis identified six hub genes associated with rupture of intracranial aneurysms

Intracranial aneurysms (IAs) are characterized by localized dilation or ballooning of a cerebral artery. When IAs rupture, blood leaks into the space around the brain to create a subarachnoid hemorrhage. The latter is associated with a higher risk of disability and mortality. The aims of this study were to gain greater insight into the pathogenesis of ruptured IAs, and to clarify whether identified hub genes represent potential biological markers for assessing the likelihood of IA progression and rupture. Briefly, the GSE36791 and GSE73378 datasets from the National Center of Biotechnology Information Gene Expression Omnibus database were reanalyzed and subjected to a weighted gene co-expression network analysis to test the association between gene sets and clinical features. The clinical significance of these genes as potential biomarkers was also examined, with their expression validated by quantitative real-time PCR. A total of 14 co-expression modules and 238 hub genes were identified. In particular, three modules (labeled turquoise, blue, and brown) were found to highly correlate with IA rupture events. Additionally, six potential biomarkers were identified (BASP1, CEBPB, ECHDC2, GZMK, KLHL3, and SLC2A3), which are strongly associated with the progression and rupture of IAs. Taken together, these findings provide novel insights into potential molecular mechanisms responsible for IAs and they highlight the potential for these particular genes to serve as biomarkers for monitoring IA rupture.