Female sex as a risk factor for the growth of asymptomatic unruptured cerebral saccular aneurysms in elderly patients

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.

Predictors of aneurysm occlusion after treatment with flow diverters: a systematic literature review

BACKGROUND

Flow diverters (FDs) have become an integral part of treatment for brain aneurysms.

AIM

To summarize available evidence of factors associated with aneurysm occlusion (AO) after treatment with a FD.

METHODS

References were identified using the Nested Knowledge AutoLit semi-automated review platform between January 1, 2008 and August 26, 2022. The review focuses on preprocedural and postprocedural factors associated with AO identified in logistic regression analysis. Studies were included if they met the inclusion criteria of study details (ie, study design, sample size, location, (pre)treatment aneurysm details). Evidence levels were classified by variability and significancy across studies (eg, low variability ≥5 studies and significance in ≥60% throughout reports).

RESULTS

Overall, 2.03% (95% CI 1.22 to 2.82; 24/1184) of screened studies met the inclusion criteria for predictors of AO based on logistic regression analysis. Predictors of AO with low variability in multivariable logistic regression analysis included aneurysm characteristics (aneurysm diameter), particularly complexity (absence of branch involvement) and younger patient age. Predictors of moderate evidence for AO included aneurysm characteristics (neck width), patient characteristics (absence of hypertension), procedural (adjunctive coiling) and post-deployment variables (longer follow-up; direct postprocedural satisfactory occlusion). Variables with a high variability in predicting AO following FD treatment were gender, FD as re-treatment strategy, and aneurysm morphology (eg, fusiform or blister).

CONCLUSION

Evidence of predictors for AO after FD treatment is sparse. Current literature suggests that absence of branch involvement, younger age, and aneurysm diameter have the highest impact on AO following FD treatment. Large studies investigating high-quality data with well-defined inclusion criteria are needed for greater insight into FD effectiveness.

Artificial intelligence aneurysm measurement tool finds growth in all aneurysms that ruptured during conservative management

BACKGROUND

Cerebral aneurysm rupture is associated with high rates of morbidity and mortality. Detecting aneurysms at high risk of rupture is critical in management decision making. Rupture risk has traditionally been associated with size-measured as a maximum dimension. However, aneurysms are morphologically dynamic, a characteristic ignored by large prospective aneurysm risk studies. Manual measurement is challenging and fraught with error. We used an artificial intelligence (AI) measurement tool to study aneurysms that ruptured during conservative management to detect changes in size not appreciated by manual linear measurement.

METHODS

A single practice database with >5000 aneurysms was queried. Patients followed conservatively for an unruptured aneurysm were identified using appropriate diagnosis codes. This cohort was screened for subsequent rupture using procedure codes. Only patients with two vascular imaging studies before rupture were included.

RESULTS

Five patients met the criteria. All patients had aneurysm enlargement, two of which were not detected from manual linear measurements, including adjudication and analysis, during a multidisciplinary neurovascular conference in a high volume practice. Maximum dimension increased at a minimum of 1.8% (range 1.8-63.3%) from the first scan to the last, and aneurysm volume increased at a minimum of 5.9% (5.9-385.5%), highlighting the importance of volumetric measurement.

CONCLUSIONS

AI-enabled volumetric measurements are more sensitive to changes in size and detected enlargement in all aneurysms that ruptured during conservative management. This finding has major implications for clinical practice and methods used for interval aneurysm measurement in patients being conservatively followed.

European Stroke Organisation (ESO) guidelines on management of unruptured intracranial aneurysms

Unruptured intracranial aneurysms (UIA) occur in around 3% of the population. Important management questions concern if and how to perform preventive UIA occlusion; if, how and when to perform follow up imaging and non-interventional means to reduce the risk of rupture. Using the Standard Operational Procedure of ESO we prepared guidelines according to GRADE methodology. Since no completed randomised trials exist, we used interim analyses of trials, and meta-analyses of observational and case-control studies to provide recommendations to guide UIA management. All recommendations were based on very low evidence. We suggest preventive occlusion if the estimated 5-year rupture risk exceeds the risk of preventive treatment. In general, we cannot recommend endovascular over microsurgical treatment, but suggest flow diverting stents as option only when there are no other low-risk options for UIA repair. To detect UIA recurrence we suggest radiological follow up after occlusion. In patients who are initially observed, we suggest radiological monitoring to detect future UIA growth, smoking cessation, treatment of hypertension, but not treatment with statins or acetylsalicylic acid with the indication to reduce the risk of aneurysm rupture. Additionally, we formulated 15 expert-consensus statements. All experts suggest to assess UIA patients within a multidisciplinary setting (neurosurgery, neuroradiology and neurology) at centres consulting >100 UIA patients per year, to use a shared decision-making process based on the team recommendation and patient preferences, and to repair UIA only in centres performing the proposed treatment in >30 patients with (ruptured or unruptured) aneurysms per year per neurosurgeon or neurointerventionalist. These UIA guidelines provide contemporary recommendations and consensus statement on important aspects of UIA management until more robust data come available.

Long-term outcomes, including the survival rate and period to death, in patients over 80 years old after ruptured cerebral aneurysm clipping

OBJECTIVE

This study aimed to identify the long-term outcomes, including the survival rate, period to death, causes of death, and predictors of poor outcomes, in patients aged over 80 years who underwent surgical clipping for a ruptured anterior circulation aneurysm.

MATERIALS AND METHODS

In this retrospective observational study, the medical records of patients from April 1, 1994, to June 30, 2019, were evaluated. All patients underwent surgical clipping within 72 h of subarachnoid hemorrhage (SAH) onset. Information on the patient, SAH, and outcomes were collected.

RESULTS

The mean hospitalization and long-term follow-up periods for all patients were 54.5 days and 53.3 months, respectively. The period to death was significantly shorter in patients with modified Rankin scale (mRS) of 4-5 than for those with an mRS of 0-3 at discharge (p=0.001). The Kaplan-Meier method using the log-rank test demonstrated that patients with an mRS of 4-5 at discharge had a significantly lower survival rate compared to those with an mRS of 0-3 at discharge (p<0.05). Univariate analysis revealed that the proportion of patients with Hunt and Hess grade and presence of surgical complications were significantly larger in the group with an mRS of 4-5 than in that with an mRS of 0-3 at discharge (p=0.0013 and 0.011, respectively). Multivariate analysis demonstrated that presence of surgical complications was the only independent predictor of poor outcomes (p=0.043, odds ratio [OR] 7.937, 95% confidence interval [CI] 1.061-59.38). The Kaplan-Meier method using the log-rank test demonstrated that patients with surgical complications had a significantly lower survival rate compared to those with no surgical complications (p<0.05).

CONCLUSIONS

Especially in patients aged over 80 years, those with H-H grade 2 and a good clinical condition can be candidates for surgical clipping, whereas avoiding surgical complications is essential for achieving good outcomes.

Clinical characteristics of intracranial aneurysms in elderly patents over 70 years old: a retrospective observational study

Background

Although the characteristics of intracranial aneurysms (IAs) in different age groups have been well documented, they remain relatively unclear in elderly patients due to a lack of large sample studies.

Methods

Data from IA patients aged more than 70 years who were treated in our centre from January 2016 to January 2020 were retrospectively collected.

Results

A total of 290 elderly patients (75.9% female) with a mean age of 74.0 ± 4.7 years were analysed. Rupture occurred in 60.7% of patients, 38.6% of whom presented with meningeal irritation, and seizures were noted in 2.3%. A total of 48.9% of the patients with ruptured IAs had initial symptoms presenting with slow development, and the mean delay from ictus was prolonged to 264.2 ± 914.0 hours. In addition, 61.9% of the patients with ruptured IAs had lesions with a maximum diameter of less than 5 mm. A total of 30.3% of the patients had multiple aneurysms, 35.5% had aneurysms with irregular shapes and 54.8% had cerebrovascular atherosclerotic stenosis (CAS). Pulmonary infection (n = 138, 47.6%), hydrocephalus (n = 72, 24.8%), and thrombosis (n = 35, 12.1%) were common complications during hospitalization. By the end of the 1-year follow-up, 22.1% of the patients had unfavourable clinical outcomes, and the mortality rate was 23.4%.

Conclusions

Several characteristics regarding IAs in elderly patients were reported, including an obvious female predominance; mild, slow initial symptom development causing prolonged admission delay; a low incidence of meningeal irritation and seizures due to decreased electrophysiological activity of the neurons; increased percentages of CAS, multiple aneurysms, and aneurysms with daughter sacs causing a high risk of rupture even for small lesions; a high risk of complications during hospitalization; and relatively poor clinical outcomes.

Procedural Outcome Following Stent-Assisted Coiling for Wide-Necked Aneurysms Using Three Different Stent Models: A Single-Center Experience

Previous case series have described the safety and efficacy of different stent models for stent-assisted aneurysm coiling (SAC), but comparative analyses of procedural results are limited. This study investigates the procedural outcome and safety of three different stent models (Atlas™, LEO+™ (Baby) and Enterprise™) in the setting of elective SAC treated at a tertiary neuro-endovascular center. We retrospectively reviewed all consecutively treated patients that received endovascular SAC for intracranial aneurysms between 1 July 2013 and 31 March 2020, excluding all emergency angiographies for acute subarachnoid hemorrhage. The primary procedural outcome was the occlusion rate evaluated with the Raymond–Roy occlusion classification (RROC) assessed on digital subtraction angiography (DSA) at 6- and 12-month follow-up. Safety assessment included periprocedural adverse events (i.e., symptomatic ischemic complications, symptomatic intracerebral hemorrhage, iatrogenic perforation, dissection, or aneurysm rupture and in-stent thrombosis) and in-house mortality. Uni- and multivariable logistic regression analyses were performed to identify patient baseline and aneurysm characteristics that were associated with complete aneurysm obliteration at follow-up. A total of 156 patients undergoing endovascular treatment via SAC met the inclusion criteria. The median age was 62 years (IQR, 55–71), and 73.7% (115) of patients were female. At first follow-up (6-month) and last available follow-up (12 and 18 months), complete aneurysm occlusion was observed in 78.3% (90) and 76.9% (102) of patients, respectively. There were no differences regarding the occlusion rates stratified by stent model. Multivariable logistic analysis revealed increasing dome/neck ratio (adjusted odds ratio (aOR), 0.26.; 95% CI, 0.11–0.64; p = 0.003), increasing neck size (aOR, 0.70; 95% CI, 0.51–0.96; p = 0.027), and female sex (aOR, 4.37; 95% CI, 1.68–11.36; p = 0.002) as independently associated with treatment success. This study showed comparable rates of complete long-term aneurysm obliteration and safety following SAC for intracranial aneurysm with three different stent-models highlighting the procedural feasibility of this treatment strategy with currently available stent-models. Increased neck size and a higher dome/neck ratio were independent variables associated with less frequent complete aneurysm obliteration.

A pilot study: Gut microbiota, metabolism and inflammation in hypertensive intracerebral hemorrhage

AIMS

In recent years, the incidence rate of hypertensive intracerebral hemorrhage (HICH) has been increasing, accompanied by high mortality and morbidity, which has brought a heavy burden to the social economy. However, the pathogenesis of HICH is still unclear. This study intends to explore the mechanism of gut microbiota metabolism and inflammation in the process of HICH to provide a theoretical basis for the diagnosis and treatment of HICH.

METHODS AND RESULTS

HE staining showed that the brain tissues of model group had obvious edema injury, which indicated that the HICH model was successfully constructed. ELISA analysis showed that IL-1β and TNF-α levels in blood and brain tissues were significantly increased, and IL-10 level was significantly decreased in blood. IHC analysis showed that microglia and macrophages were activated in the model group. 16S rRNA sequence showed that the diversity of gut microbiota in HICH patients decreased. And the microbiota belonged to Firmicutes, Proteobacteria and Verrucomicrobia changed significantly. LC-MS/MS analysis showed that the metabolic phenotype of HICH patients changed. And the 3,7-Dimethyluric acid and 7-Methylxanthine related metabolic pathways of caffeine metabolism pathways were down-regulated in patients with HICH. Bacteroides was negatively correlated with the IL-1β and TNF-α level. Blautia was negatively correlated with the IL-1β and TNF-α level, and positively correlated with the IL-10 level. Akkermansia was negatively correlated with the 3,7-Dimethyluric acid and 7-Methylxanthine.

CONCLUSION

Our study suggested that HICH accompanied by the increased inflammation in peripheral blood and brain, decreased gut microbiota diversity, altered gut metabolic phenotype, and down-regulation of caffeine metabolism pathway.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our study reported that HICH accompanied by the increased inflammation, decreased gut microbiota diversity, and altered gut metabolic phenotype. Due to the number of patients, this work was a pilot study.

Intracranial hemorrhage associated with direct oral anticoagulant after clipping for an unruptured cerebral aneurysm: A report of two cases

Background:

Two cases of patients who developed intracranial hemorrhage associated with direct oral anticoagulant (DOAC) use after clipping of an unruptured cerebral aneurysm (uAN) are presented. These cases will help neurosurgeons assess the risks of patients with atrial fibrillation or deep venous thrombosis receiving DOACs who require craniotomy.

Case Description:

Case 1 was a 65-year-old man on apixaban 10 mg/day who underwent clipping for a left middle cerebral artery uAN. Apixaban was discontinued 72 h before surgery. During surgery, a thin and pial artery bled slightly at 1 point of the frontal lobe, and hemostasis was easily achieved. Computed tomography (CT) 19 h after surgery showed no evidence of intracranial hemorrhage. He was treated with a heparin-apixaban bridge from 29 h to 41 h after surgery. CT showed a left subarachnoid hematoma 24 h later. Case 2 was a 73-year-old woman on dabigatran 110 mg/day who underwent clipping for a right MCA uAN. Dabigatran was discontinued 48 h before surgery. During surgery, a thin and pial artery bled slightly at 2 points of the temporal lobe, and hemostasis was easily achieved. CT 19 h after surgery showed no evidence of intracranial hemorrhage. Dabigatran (110 mg/day) was restarted 29 h after surgery. CT then showed a right subarachnoid hematoma 94 h later, and dabigatran was discontinued, and it was then restarted 38 h later. However, 31 h later, CT showed an additional slight subarachnoid hemorrhage. Finally, she developed a right chronic subdural hematoma.

Conclusion:

In patients undergoing neurosurgical procedures, discontinuation of DOACs should be individualized based on neurosurgical bleeding risk and patient renal function. Restarting of DOACs could be considered after at least 48 h when hemostasis has been achieved. Bridging of DOACs cannot be recommended.

What Are the Predictors of Intracranial Aneurysm Rupture in Indonesian Population Based on Angiographic Findings? Insight from Intracranial Aneurysm Registry on Three Comprehensive Stroke Centres in Indonesia

Objectives

What are the Predictors of Intracranial Aneurysm (IA) Rupture based on angiographic findings among patients in Indonesia's Population Based on Angiographic Findings.

Materials and Methods

We conducted a cross-sectional study on subjects with IA not caused by congenital aetiologies or other vascular malformations with cerebral angiography performed from January 2017 to January 2021. Demographic data and aneurysm profile, which include aneurysm count, size, location, and rupture event, were collected. The correlation between risk factors and IA rupture events was determined using bivariate and multivariate analysis.

Results

From 100 angiography data (33 males and 67 females), the mean subject age is 51.94 ± 10.78. We observe a total of 121 IAs from all subjects. Most of the IAs are in the anterior circulation (104 aneurysms, 85.96%), have small size (77 aneurysms, 63.64%), and are found in ruptured conditions (90 aneurysms, 74.38%). Males have a greater aneurysm count (1.36 ± 0.74 vs. 1.13 ± 0.55, p = 0.036) and larger aneurysm size (p = 0.002). Aneurysm size is significantly correlated with its location (p = 0.008). Medium size (p = 0.019; OR 2.62, 95% CI 1.08-6.36) and location other than the internal carotid artery are associated with increased rupture event. Multivariate analysis revealed that gender (p = 0.031; aOR 5.37, 95% CI 1.17-24.70) is a significant risk factor of IA rupture event.

Conclusion

IA profiling will enable clinicians to determine the risk of rupture and treatment plans for the Indonesian population. Further studies with a larger sample size are required to confirm these findings.

Why Are Women Predisposed to Intracranial Aneurysm?

Intracranial aneurysm (IA) is a frequent and generally asymptomatic cerebrovascular abnormality characterized as a localized dilation and wall thinning of intracranial arteries that preferentially arises at the arterial bifurcations of the circle of Willis. The devastating complication of IA is its rupture, which results in subarachnoid hemorrhage that can lead to severe disability and death. IA affects about 3% of the general population with an average age for detection of rupture around 50 years. IAs, whether ruptured or unruptured, are more common in women than in men by about 60% overall, and more especially after the menopause where the risk is double-compared to men. Although these data support a protective role of estrogen, differences in the location and number of IAs observed in women and men under the age of 50 suggest that other underlying mechanisms participate to the greater IA prevalence in women. The aim of this review is to provide a comprehensive overview of the current data from both clinical and basic research and a synthesis of the proposed mechanisms that may explain why women are more prone to develop IA.

Formation, Growth, or Rupture of De Novo Intracranial Aneurysms: Long-Term Follow-up Study of Subarachnoid Hemorrhage Survivors

BACKGROUND

The survival rate of aneurysmal subarachnoid hemorrhage (aSAH) has gradually increased, leading to more clinical cases of de novo intracranial aneurysms (DNIAs).

OBJECTIVE

To identify the characteristics of patients with DNIA growth or rupture.

METHODS

We included 1601 patients with aSAH treated by clipping from January 1993 to May 2010. According to the inclusion and exclusion criteria, 233 patients had no DNIAs, and 63 patients had 77 DNIAs. We assessed the incidence rate of DNIAs and risk factors for DNIA formation. After dichotomizing the DNIA group into the heed (patients with DNIA rupture or growth) and stable groups (patients without DNIA growth), we assessed the risk factors for DNIA growth or rupture.

RESULTS

The total follow-up period was 4427.9 patient-years. The incidence rate per patient-year was 1.42%. Age ≤50 yr, family history of aneurysm, and multiplicity at initial aSAH were significant risk factors for DNIA formation. Multivariate regression analysis revealed that female sex (odds ratio [OR], 5.566; 95% confidence interval [CI], 1.241-24.952), duration from initial aSAH to DNIA detection <120 mo (OR, 5.043; 95% CI, 1.362-18.668), multiplicity at initial aSAH (OR, 4.859; 95% CI, 1.207-19.563), and maximum DNIA diameter ≥4 mm (OR, 11.104; 95% CI, 2.337-52.772) were significant risk factors for DNIA growth or rupture.

CONCLUSION

DNIAs had a higher incidence rate than expected. Taking into account the presented incidence rate and risk factors, long-term surveillance in aSAH survivors for more than a decade may be worth considering, at least on a case-by-case basis.

Risk factors for the progression of unruptured intracranial aneurysms in patients followed by CT/MR angiography

Background

The progression of an unruptured intracranial aneurysm (UIA) is associated with a higher rupture risk. The aim of this study was to identify the risk factors for the progression of UIAs among Chinese adults and compare them with the ELAPSS (Earlier subarachnoid hemorrhage, IA Location, Age, Population, IA Size and Shape) score.

Methods

Four hundred thirty-eight consecutive patients with 491 UIAs were followed and reviewed retrospectively from August 2011 to November 2019. Follow-up images of the UIAs were used to determine changes in IA size and shape. Patients and IAs were divided into non-progression and progression groups. In addition to the clinical characteristics of the patients, the features of the IAs (e.g., size and shape) were evaluated by computed tomography angiography (CTA) or magnetic resonance angiography (MRA). Independent risk factors for UIA progression were studied using multiple Cox proportional hazards regression analysis. In addition, the diagnostic value of the ELAPSS score for the prediction of UIA progression was calculated.

Results

Seventy-two IAs in 68 patients progressed during a mean follow-up time of 24.2±19.68 months. IAs located at the bifurcation [odds ratio (OR) 2.600], with an irregular shape (OR 2.981) or having a high aspect ratio (AR, OR 2.430) were correlated with progression. Based on these three factors, the threshold value of our predictive score was 0.5, and the area under the curve (AUC), sensitivity and specificity were 0.756, 93.1% and 40.6%, respectively, while the AUC, sensitivity and specificity of the ELAPSS score were 0.711, 55.6%, and 75.2%, respectively.

Conclusions

IAs located at the bifurcation, with an irregular shape and with an elevated AR are risk factors for UIA progression in the Chinese population. Our predictive score is of great value in predicting the risk of UIA progression.

Knowledge framework and emerging trends in intracranial aneurysm magnetic resonance angiography: a scientometric analysis from 2004 to 2020

Background

As magnetic resonance angiography (MRA) has been increasingly used in the follow-up of intracranial aneurysms (IAs) as a non-invasive technique, the knowledge framework and areas of research interest in intracranial aneurysms magnetic resonance angiography (IAMRA) change approximately every 10 years. However, few studies have quantitatively analyzed the published literature in this field. In the present study, we used scientometrics to survey the knowledge field, development trends, and research focus of IAMRA with the aim of providing a reference for further study.

Methods

We collected articles on IAMRA published from 2004 (Jan 1, 2004) to 2020 (May 24, 2020). Web of Science Core Collection databases (WoSCCd) including the Science Citation Index Expanded were searched. An experienced staff member from the Department of Radiology at Southern Medical University, assisted in screening articles for relevant articles. We used ArcGIS (a mapping and location analytics platform) to perform geographic visualization. Excel 2016 was used to analyze the literature data, including number of publications, impact factor (IF), and publication year. CiteSpace V was used to conduct a series of literature feature clustering, including author co-citation analysis, reference co-citation analysis (RCA), and burst keywords analysis.

Results

A total of 1,272 articles on IAMRA published between 2004 and 2020 were included. Of 257 journals, American Journal of Neuroradiology (IF 2018: 3.256) published the most IAMRA articles (109 publications, 8.57%), followed by Journal of Neurosurgery (IF 2018: 4.131, 51 publications, 4.16%), and Neuroradiology (IF 2018: 2.504, 51 publications, 4.01%). Of 56 countries, the USA published the most, with 347 articles [27.28%, IF: 3.14 (average IF of all journals in the country)], followed by Japan (242 articles, 19.03%, IF: 2.38), Germany (135 articles, 10.61%, IF: 3.21), and China (101 articles, 7.94%, IF: 2.86). A total of 1387 institutions published articles, with the Mayo Clinic publishing the most (33 articles, 2.59%), followed by Shanghai Jiao Tong University (25 article, 1.97%), Seoul National University (23 articles, 1.81%), and University Medical Center Utrecht (19 articles, 1.49%). Of 399 authors, Rinkel ranked first with 19 articles, followed by Li MH (18 articles), Uchino A (15 articles), and Saito N (13 articles). Cluster RCA showed that the first cluster was "#0 growth", followed by "#1 Guglielmi detachable coils". Timeline views showed that the time span of "#0 growth" was the closest to today. The modularity value was 0.6971, and the mean silhouette value was 0.5477. According to the burst keyword analysis, "risk factors associated to rupture" was the topic with the strongest burst since 2017. Studies conducted in several countries suggested that age is inversely related to the risk of rupture, which implies the importance of MRA follow-up for patients of different age.

Conclusions

From 2004 to 2020, the number of published IAMRA-related articles gradually increased. The USA and Western Europe lead in the field, with a concentration of cutting-edge talents and high-level scientific research institutions. A synthesis of the clustering results of RCA and burst keyword analysis indicated that unruptured IA growth, stent-assisted coil embolization, and risk factors associated to rupture were the current hotspots in IAMRA research.

Association of zinc administration with growth suppression of intracranial aneurysms via induction of A20

OBJECTIVE

Zinc is an essential micronutrient with multiple biological effects, including antiinflammation. Previously, the authors demonstrated that the pathogenesis of intracranial aneurysms (IAs) is strongly related to chronic inflammation. In this study, the authors investigated whether administration of zinc inhibits the growth of IAs in a rat model.

METHODS

The authors analyzed surgically induced IAs in Sprague-Dawley male rats, which were subsequently treated with intraperitoneal injections of zinc sulfate heptahydrate (ZnSO4; 3 mg/kg/day) or vehicle for 4 weeks.

RESULTS

Size and wall thickness ratios of experimentally induced IAs were assessed in both treatment groups after induction and in a control group. The effects of zinc administration in IAs were examined by immunohistochemistry and Western blotting. Zinc administration significantly suppressed aneurysm size and also preserved the internal elastic lumen. Administration of zinc significantly attenuated infiltration of macrophages into IAs.

CONCLUSIONS

Zinc treatment significantly increased expression of the antiinflammatory signaling protein A20, an inhibitor of the nuclear factor κB (NF-κB) pathway, in rat IAs. Zinc administration may prevent the growth of rat IAs by inducing A20-attributed inactivation of NF-κB signaling.

Aging Changes of Aneurysmal Subarachnoid Hemorrhage: A 35-year, Hospital-Based Study

BACKGROUND

The etiology and background factors which cause decreases in the size of ruptured intracranial aneurysms remain unclear.

OBJECTIVE

To clarify the age- and sex-related differences in aneurysmal subarachnoid hemorrhage (SAH) based on a 35-year-old hospital database and demographic data.

METHODS

A database of patients admitted to our hospital with aneurysmal SAH from 1983 to 2017 was split into 5-year intervals and analyzed. Demographic data of the general population were also analyzed for reference.

RESULTS

Altogether, 1,523 aneurysmal SAH events were enrolled in the analysis. Age (p<0.001), proportion of elderly patients ≥ 65 years old (p<0.001), female sex (p=0.005), very small aneurysms less than 5 mm (p<0.001), and the yearly-averaged number of fatal events showed increasing trends. The proportion of aneurysm size of 10 mm or more (p = 0.011) and the yearly-averaged population of Shimane prefecture (p < 0.001) showed declining trends. In the subgroup analyses, the proportion of very small aneurysms was found to increase significantly in the non-elderly male and elderly female subgroups. The proportion of large aneurysms (10 mm or more) decreased in the non-elderly subgroup (p<0.05). As for the elderly subgroups, the yearly-averaged number of events did not show a significant tendency, although the yearly-averaged population of Shimane prefecture showed an increasing trend.

CONCLUSION

We found an increasing trend in the prevalence of very small aneurysms in elderly females. Recent aging may contribute to this trend. The number of aneurysmal SAH events was confirmed to not increase, despite the increased aging population of Shimane prefecture.

Circumferential wall enhancement in evolving intracranial aneurysms on magnetic resonance vessel wall imaging

OBJECTIVE

Recent MR vessel wall imaging studies have indicated intracranial aneurysms in the active state could show circumferential enhancement along the aneurysm wall (CEAW). While ruptured aneurysms frequently show CEAW, CEAW in unruptured aneurysms at the evolving state (i.e., growing or symptomatic) has not been studied in detail. The authors quantitatively assessed the degree of CEAW in evolving unruptured aneurysms by comparing it separately to that in stable unruptured and ruptured aneurysms.

METHODS

A quantitative analysis of CEAW was performed in 26 consecutive evolving aneurysms using MR vessel wall imaging. Three-dimensional T1-weighted fast spin echo sequences were obtained before and after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CRstalk) was calculated as the indicator of CEAW. Aneurysm characteristics of evolving aneurysms were compared with those of 69 stable unruptured and 67 ruptured aneurysms.

RESULTS

The CRstalk values in evolving aneurysms were significantly higher than those in stable aneurysms (0.54 vs 0.34, p < 0.0001), and lower than those in ruptured aneurysms (0.54 vs 0.83, p < 0.0002). In multivariable analysis, CRstalk remained significant when comparing evolving with stable aneurysms (odds ratio [OR] 12.23, 95% confidence interval [CI] 3.53-42.41), and with ruptured aneurysms (OR 0.083, 95% CI 0.022-0.310).

CONCLUSIONS

The CEAW in evolving aneurysms was higher than those in stable aneurysms, and lower than those in ruptured aneurysms. The degree of CEAW may indicate the process leading to rupture of intracranial aneurysms, which can be useful additional information to determine an indication for surgical treatment of unruptured aneurysms.

Association of Bone Mineral Density With the Risk of Intracranial Aneurysm

Importance

Disruption of extracellular matrix integrity is critically involved in both intracranial aneurysm and bone fragility. Furthermore, both intracranial aneurysm and osteoporosis have a female predominance, and sex hormones are considered to affect this discrepancy.

Objective

To evaluate the association between bone mineral density and intracranial aneurysm.

Design, Setting, and Participants

A cross-sectional study conducted with 14 328 patients who underwent brain magnetic resonance angiography and bone mineral densitometry as a part of a health examination at a specialized center for comprehensive health examination in Seoul, the largest metropolitan area in the Republic of Korea, between December 2004 and November 2015. After excluding patients with insufficient clinical information (n = 1102) and with ambiguous intracranial arterial lesion (n = 441), 12 785 were included in the analysis.

Exposures

Bone mineral density was measured at the lumbar vertebrae (L1 to L4), femur neck, and total hip using dual-energy x-ray absorptiometry.

Main Outcomes and Measures

Multiple logistic regression or linear regression was used to examine the association between tertiles of bone mineral density and the presence, size, and multiplicity of intracranial aneurysms. In secondary analyses, we analyzed postmenopausal women and men 50 years and older (n = 8722) because they are particularly at risk of decreased bone mineral density.

Results

Among 12 785 patients in the study (7242 women [56.6%]; mean [SD] age, 54.8 [10.1] years) intracranial aneurysms were found in 472 patients (3.7%). Lower bone mineral density was associated with an increased risk of harboring intracranial aneurysm. In multivariable logistic regression analyses, odds ratios for the highest compared with the lowest bone mineral density tertile were 1.30 (95% CI, 1.03-1.64) in the lumbar spine, 1.30 (95% CI, 1.03-1.64) in the femoral neck, and 1.27 (95% CI, 1.01-1.60) in the total hip after adjusting for age, sex, and vascular risk factors. In a linear regression model adjusted for age, sex, and vascular risk factors, the lowest tertile of bone mineral density in the lumbar spine was associated with an increased log-transformed size of aneurysm (β, 0.196; SE, 0.047). In secondary analyses, these associations were more definite and a low T score (<-1 SD) was additionally associated with multiple aneurysms (OR, 1.84; 95% CI, 1.05-3.30) after adjusting for age, sex, and vascular risk factors.

Conclusions and Relevance

Bone mineral density may be associated with the presence, size, and multiplicity of intracranial aneurysm. The study findings provide evidence for shared pathophysiology between intracranial aneurysm and bone fragility.

A systematic review and meta-analysis of risk factors for unruptured intracranial aneurysm growth

BACKGROUND

Many risk factors are associated with the growth of unruptured intracranial aneurysm; however, the effects of these risk factors on intracranial aneurysm growth remain poorly understood. Here, we performed a meta-analysis to evaluate the effects of these risk factors on intracranial aneurysm growth, incorporating different data types to provide comprehensive estimates of individual effects.

METHODS

We searched the Cochrane Library, PubMed, Embase, and Web of Science for cohort studies analyzing risk factors for aneurysm growth prior to January 10, 2019. The hazard ratio (HR) and odds ratio (OR) with its 95% confidence interval (CI) were calculated to assess the effect of individual risk factors on intracranial aneurysm growth. Both univariate analysis (UVA) and multivariate analysis (MVA) were performed. Two reviewers independently assessed the quality of the trials and the associated data. All statistical analyses were performed using standard statistical procedures provided in Review Manager 5.2.

RESULTS

We included 23 studies (N = 7208 participants) in this meta-analysis. A total of 944 patients (13.1%) experienced intracranial aneurysm growth during their follow-up times. Aneurysm size and smoking may have significant effects on the growth of intracranial aneurysm, with pooled ORs of 2.73 (95% CI 2.21-3.36; P < 0.00001) and 1.45 (95% CI 1.07-1.98; P = 0.02) respectively. However, our results indicated that subarachnoid hemorrhage (SAH) had a negative effect on the growth of intracranial aneurysm (OR 0.64; 95% CI 0.48-0.86; P = 0.003). Other risk factors such as irregular shape of intracranial aneurysm, female sex, and multiple aneurysms were inconsistent across studies due to differences in data types and effect estimates.

CONCLUSIONS

Our meta-analysis identified aneurysm size and smoking as independent risk factors for the growth of intracranial aneurysm, while prior SAH had a negative effect on the growth of intracranial aneurysm. The roles of other risk factors for intracranial aneurysm growth were inconsistent, with further research necessary to assess fully the roles of these factors in disease outcomes.

Endothelial dysfunction in cerebral aneurysms

Endothelial cell (EC) dysfunction is known to contribute to cerebral aneurysm (CA) pathogenesis. Evidence shows that damage or injury to the EC layer is the first event in CA formation. The mechanisms behind EC dysfunction in CA disease are interrelated and include hemodynamic stress, hazardous nitric oxide synthase (NOS) activity, oxidative stress, estrogen imbalance, and endothelial cell-to-cell junction compromise. Abnormal variations in hemodynamic stress incite pathological EC transformation and inflammatory zone formation, ultimately leading to destruction of the vascular wall and aneurysm dilation. Hemodynamic stress activates key molecular pathways that result in the upregulation of chemotactic cytokines and adhesion molecules, leading to inflammatory cell recruitment and infiltration. Concurrently, oxidative stress damages EC-to-EC junction proteins, resulting in interendothelial gap formation. This further promotes leukocyte traffic into the vessel wall and the release of matrix metalloproteinases, which propagates vascular remodeling and breakdown. Abnormal hemodynamic stress and inflammation also trigger adverse changes in NOS activity, altering proper EC mediation of vascular tone and the local inflammatory environment. Additionally, the vasoprotective hormone estrogen modulates gene expression that often suppresses these harmful processes. Crosstalk between these sophisticated pathways contributes to CA initiation, progression, and rupture. This review aims to outline the complex mechanisms of EC dysfunction in CA pathogenesis.

Genome-Wide Association between the 2q33.1 Locus and Intracranial Aneurysm Susceptibility: An Updated Meta-Analysis Including 18,019 Individuals

Previous genome-wide association studies did not show a consistent association between the BOLL gene (rs700651, 2q33.1) and intracranial aneurysm (IA) susceptibility. We aimed to perform an updated meta-analysis for the potential IA-susceptibility locus in large-scale multi-ethnic populations. We conducted a systematic review of studies identified by an electronic search from January 1990 to March 2019. The overall estimates of the "G" allele of rs700651, indicating IA susceptibility, were calculated under the fixed- and random-effect models using the inverse-variance method. Subsequent in silico function and cis-expression quantitative trait loci (cis-eQTL) analyses were performed to evaluate biological functions and genotype-specific expressions in human tissues. We included 4513 IA patients and 13,506 controls from five studies with seven independent populations: three European-ancestry, three Japanese, and one Korean population. The overall result showed a genome-wide significance threshold between rs700651 and IA susceptibility after controlling for study heterogeneity (OR = 1.213, 95% CI: 1.135-1.296). Subsequent cis-eQTL analysis showed significant genome-wide expressions in three human tissues, i.e., testis (p = 8.04 × 10^-15 for ANKRD44), tibial nerves (p = 3.18 × 10^-10 for SF3B1), and thyroid glands (p = 4.61 × 10^-9 for SF3B1). The rs700651 common variant of the 2q33.1 region may be involved in genetic mechanisms that increase the risk of IA and may play crucial roles in regulatory functions.

Treatment Strategy for Unruptured Intracranial Aneurysm in Elderly Patients: Coiling, Clipping, or Conservative?

An increasing number of unruptured intracranial aneurysms (UIAs) has been discovered in elderly patients in recent years, but the optimal treatment strategy for these patients remains controversial. We report our six-year experience treating UIAs in elderly patients (≥ 70 years old). A retrospective review was conducted of elderly patients who harbored UIAs treated by conservative observation, microsurgical clipping, or endovascular coiling between January 2009 and December 2014. The patients’ clinical and imaging information was recorded. Treating methods, procedure-related complications, imaging results, and clinical outcomes were analyzed. A total of 141 consecutive elderly patients with 166 UIAs were enrolled in our study. In all, 64 patients with 79 aneurysms were treated with coiling, and 14 patients with 14 aneurysms were treated with clipping. The remaining 63 patients with 73 aneurysms were placed under conservative observation. The average modified Rankin scale was 0.99 (range 0–6) in the full cohort after a mean follow-up of 50.4 months (range 0–70 months). There was no significant difference of modified Rankin scale in patients with UIAs treated by different methods. Multivariate analysis showed that age (p=0.030) and aneurysm size (p=0.011) were independent risk factors for unfavorable outcome of UIAs in the elderly. Patient age (p=0.010) and aneurysm size (p=0.020) were also significantly associated with unfavorable outcome of UIAs managed with observation initially. Our results indicated that endovascular coil embolization and clipping were both safe and effective treatment methods for UIAs in the elderly. Aggressive treatment for UIAs in elderly patients with risk factors of aneurysm rupture should be considered positively.

Association between polymorphism of SMAD3 gene and risk of sporadic intracranial arterial aneurysms in the Chinese Han population

Intracranial arterial aneurysms (IAAs) are locally abnormal dilations of the cerebral arteries and often result in subarachnoid hemorrhages (SAH). Genetic, molecular and cellular mechanisms of sporadic IAAs forms are poorly understood. In this study, we investigate the association between mothers against decapentaplegic homolog 3 (SMAD3) genotypes and the risk of sporadic intracranial arterial aneurysms among the Chinese Han population. A case-control study was conducted examining 330 IAA patients and 313 controls. There were eight single nucleotide polymorphisms of SMAD3 selected and genotyped using the polymerase chain reaction-ligase detection reaction (PCR-LDR) method. Our results indicated that SMAD3 rs1065080 polymorphism was associated with a risk of IAAs in a codominant model (GA vs GG, OR=1.433; 95% CI 1.030-1.994; P=0.032). In summary, we observed that SMAD3 rs1065080 single nucleotide gene polymorphisms were significantly associated with patient susceptibility to IAAs.

Predictors of Postoperative Cerebral Ischemia in Patients with Ruptured Anterior Communicating Artery Aneurysms

OBJECTIVE

Cerebral ischemia is a major contributor to poor outcome after ruptured anterior communicating artery aneurysms (ACoAs), and is not well classified. In this article, we develop a classification and identify risk factors of cerebral ischemia after ruptured ACoAs.

METHODS

Three hundred sixty patients with ruptured ACoAs undergoing microsurgical clipping were collected. Sex, age, smoking status, Hunt-Hess grade, Fisher grade, hospital stay, surgical timing, hypertension, diabetes, postoperative cerebral ischemia, and postoperative modified Rankin Scale score were collected. Postoperative ischemic changes are classified according to a novel grade (ischemic grade I-IV).

RESULTS

Predictive factors of postoperative ischemia (grade I-IV) included sex (odds ratio [OR], 1.956; 95% confidence interval [CI], 1.262-3.032; P = 0.003) and Fisher grade (OR, 1.813; 95% CI, 1.144-2.871; P = 0.011). Male sex had a tendency to develop postoperative cerebral ischemia (61.3% in the ischemia group vs. 45.7% in the nonischemia group), while surgical timing did not. However, in patients with postoperative ischemia, early surgery within 3 days (OR, 3.334; 95% CI, 1.411-7.879; P = 0.006) and advanced age greater than 55 years (OR, 2.783; 95% CI, 1.214-6.382; P = 0.016) were risk factors for postoperative neurologic deficits (grade III-IV).

CONCLUSIONS

Male sex and higher Fisher grade predict postoperative ischemia (grade I-IV), whereas surgical timing does not. However, in patients with postoperative cerebral ischemia, early surgery within 3 days and age greater than 55 years can increase the frequency of postoperative neurological deficits (grade III-IV). Older male patients undergoing early microsurgery had a tendency to develop neurologic deficits.

Thoracic Aortic Aneurysm Growth: Role of Sex and Aneurysm Etiology

BACKGROUND

Thoracic aortic aneurysm (TAA) outcomes are worse in women than men, although reasons for sex differences are unknown. Because faster TAA growth is a risk factor for acute aortic syndromes, we sought to determine the role of sex and aneurysm etiology on TAA growth.

METHODS AND RESULTS

Eighty-two consecutive unoperated subjects with TAA who had serial aneurysm measurements were recruited. In multivariable linear regression the association of female sex with aneurysm growth rate was assessed after adjustment for potential confounders. We also tested the interaction term sex×aneurysm etiology in the prediction of TAA growth. Seventy-four percent of subjects were men; mean±SD age was 62.4±11.9 years in men and 67.7±10.7 years in women (P=0.06). Forty-seven (57%) subjects had degenerative TAAs, and the remainder had heritable TAAs. Absolute baseline aneurysm size and follow-up time were not different between men and women. Aneurysm growth rate was 1.19±1.15 mm/y in women and 0.59±0.66 mm/y in men (P=0.02). Female sex remained significantly associated with greater aneurysm growth in multivariable analyses (β±SE: 0.35±0.12, P=0.005). In addition, female sex was associated with faster TAA growth only among those with degenerative TAA (β±SE: 0.33±0.08, P=0.0002) and not among those with heritable TAA (P=0.79), with a significant sex×etiology interaction (P=0.001).

CONCLUSIONS

TAA growth rates are greater in women than men, and this difference is specific to women with degenerative TAAs. Our findings may explain sex differences in TAA outcomes and provide a foundation for future investigations of this topic.

Risk Factors for Growth of Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Understanding risk factors for intracranial aneurysm growth is important for patient management. We performed a meta-analysis examining risk factors for intracranial aneurysm growth in longitudinal studies and examined the association between aneurysm growth and rupture.

MATERIALS AND METHODS

We searched the literature for longitudinal studies of patients with unruptured aneurysms. We examined the associations of demographics, multiple aneurysms, prior subarachnoid hemorrhage, family history of aneurysm or subarachnoid hemorrhage, smoking, and hypertension; and aneurysm shape, size, and location with aneurysm growth. We studied the association between aneurysm growth and rupture. A meta-analysis was performed by using a random-effects model by using summary statistics from included studies.

RESULTS

Twenty-one studies including 3954 patients with 4990 aneurysms with 13,294 aneurysm-years of follow-up were included. The overall proportion of growing aneurysms was 3.0% per aneurysm-year (95% CI, 2.0%-4.0%). Patient risk factors for growth included age older than 50 years (3.8% per year versus 0.9% per year, P < .01), female sex (3.2% per year versus 1.3% per year, P < .01), and smoking history (5.5% per year versus 3.5% per year, P < .01). Characteristics associated with higher growth rates included cavernous carotid artery location (14.4% per year), nonsaccular shape (14.7% per year versus 5.2% per year for saccular, P < .01), and aneurysm size (P < .01). Aneurysm growth was associated with a rupture rate of 3.1% per year compared with 0.1% per year for stable aneurysms (P < .01).

CONCLUSIONS

Observational evidence provided multiple clinical and anatomic risk factors for aneurysm growth, including age older than 50 years, female sex, smoking history, and nonsaccular shape. These findings should be considered when counseling patients regarding the natural history of unruptured intracranial aneurysms.

Sex Differences in the Formation of Intracranial Aneurysms and Incidence and Outcome of Subarachnoid Hemorrhage: Review of Experimental and Human Studies

Intracranial aneurysms are defined as pathological dilatations of cerebral arteries and rupture of intracranial aneurysms leads to subarachnoid hemorrhage (SAH). The goal of this review was to outline the sex differences in the formation and progression of intracranial aneurysms as well as sex-related differences in incidence and outcome of SAH. The literature review was performed using PubMed with a combination of these search terms: "subarachnoid hemorrhage," "incidence," "outcome," "sex," "gender," "male," "female," "experimental," "mice," and "rats." Studies written in English were used. Female sex is thought to be a risk factor for aneurysm formation, especially in postmenopausal age populations, suggesting the potential protective involvement of sex steroids. Female sex is also considered a risk factor for SAH occurrence. Although incidence and mortality are confirmed to be higher in females in most studies, they elucidated no clear differences in the functional outcome among SAH survivors. The effect of gender on the pathophysiology of SAH is not very well understood; nevertheless, the majority of pre-clinical studies suggest a beneficial effect of sex steroids in experimental SAH. Moreover, conflicting results exist on the role and effect of hormone replacement therapies and oral contraceptive pills on the incidence and outcome of human SAH. Sex differences exist in the formation of aneurysms as well as the incidence and mortality of SAH. Potential therapeutic effects of sex steroids have been replicated in many animal studies, but their potential use in the treatment of acute SAH in human populations needs more future study.

Risk of rupture of unruptured cerebral aneurysms in elderly patients

Objectives:

The aim of this study was to identify risk factors for rupture of unruptured cerebral aneurysms (UCAs) in elderly Japanese patients aged 70 years or older.

Methods:

The participants included all patients 70 years of age or older in 3 prospective studies in Japan (the Unruptured Cerebral Aneurysm Study of Japan [UCAS Japan], UCAS II, and the prospective study at the Jikei University School of Medicine). A total of 1,896 patients aged 70 years or older with 2,227 UCAs were investigated. The median and mean follow-up periods were 990 and 802.7 days, respectively.

Results:

The mean aneurysm size was 6.2 ± 3.9 mm. Sixty-eight patients (3.6%) experienced subarachnoid hemorrhage during the follow-up period. Multivariable analysis per patient revealed that in patients aged 80 years or older (hazard ratio [HR], 2.02; 95% confidence interval [CI], 1.16–3.49, p = 0.012), aneurysms 7 mm or larger (HR, 3.08; 95% CI, 1.35–7.03, p = 0.007 for 7–9 mm; HR, 7.82; 95% CI, 3.60–16.98, p < 0.001 for 10–24 mm; and HR, 43.31; 95% CI, 12.55–149.42, p < 0.001 for ≥25 mm) and internal carotid–posterior communicating artery aneurysms (HR, 2.45; 95% CI, 1.23–4.88, p = 0.011) were independent predictors for UCA rupture in elderly patients.

Conclusions:

In our pooled analysis of prospective cohorts in Japan, patient age and aneurysm size and location were significant risk factors for UCA rupture in elderly patients.

Guidelines for the Management of Patients With Unruptured Intracranial Aneurysms: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

PURPOSE

The aim of this updated statement is to provide comprehensive and evidence-based recommendations for management of patients with unruptured intracranial aneurysms.

METHODS

Writing group members used systematic literature reviews from January 1977 up to June 2014. They also reviewed contemporary published evidence-based guidelines, personal files, and published expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulated recommendations using standard American Heart Association criteria. The guideline underwent extensive peer review, including review by the Stroke Council Leadership and Stroke Scientific Statement Oversight Committees, before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with unruptured intracranial aneurysms. The guidelines address presentation, natural history, epidemiology, risk factors, screening, diagnosis, imaging and outcomes from surgical and endovascular treatment.