Differences in anatomical distribution, gender, and sidedness between ruptured and unruptured intracranial aneurysms in a defined patient population

Aneurysmal Subarachnoid Hemorrhage and Sex Differences: Analysis of Epidemiology, Outcomes, and Risk Factors

BACKGROUND

The differences in outcomes after aneurysmal subarachnoid hemorrhage (aSAH) between the sexes have not been concretely determined. This study aimed to evaluate the differences in epidemiology, outcomes, and risk factors between male and female patients with aSAH.

METHODS

We performed a multicenter, retrospective study of patients with aSAH from 2017 to 2020. We investigated the epidemiological differences between the two sexes. Propensity score matching (PSM) was used to compare short-term outcomes between the sexes. Binary logarithmic regression was performed to investigate the odds ratio (OR) for dependent survival in patients of different sexes.

RESULTS

A total of 5,407 consecutive patients with aSAH were included in this study, and the female-to-male ratio was 1.8:1. The peak incidence of aSAH occurred in the 6th and 7th decades in males and females, respectively. There were more female patients with internal carotid artery or posterior communicating artery aneurysms (53.2%), and there were more male patients with anterior cerebral artery or anterior communicating artery aneurysms (43.2%). The incidence of multiple aneurysms was greater in female patients (21.5% vs. 14.2%, P < 0.001). There was no significant difference in outcomes before and after PSM at discharge. The dependent survival risk was related only to the clinical condition on admission in women. In addition, age > 50 years (OR 1.88, 95% confidence interval 1.17-3.02; P = 0.01) and hypertension (OR 1.81, 95% confidence interval 1.25-2.61; P = 0.002) were also risk factors for male patients.

CONCLUSIONS

There were more female patients with aneurysms than male patients in this study. Most aneurysm locations were different between the two groups. There was no significant difference in discharge outcomes before and after PSM. The risk factors for dependent survival were different between female and male patients.

Sex-Related Differences in Mortality, Delayed Cerebral Ischemia, and Functional Outcomes in Patients with Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

Background/Objective: Sex-related differences among patients with aneurysmal subarachnoid hemorrhage (aSAH) and their potential clinical implications have been insufficiently investigated. To address this knowledge gap, we conduct a comprehensive systematic review and meta-analysis. Methods: Sex-specific differences in patients with aSAH, including mortality, delayed cerebral ischemia (DCI), and functional outcomes were assessed. The functional outcome was dichotomized into favorable or unfavorable based on the modified Rankin Scale (mRS), Glasgow Outcome Scale (GOS), and Glasgow Outcome Scale Extended (GOSE). Results: Overall, 2823 studies were identified in EMBASE, MEDLINE, PubMed, and by manual search on 14 February 2024. After an initial assessment, 74 studies were included in the meta-analysis. In the analysis of mortality, including 18,534 aSAH patients, no statistically significant differences could be detected (risk ratio (RR) 0.99; 95% CI, 0.90-1.09; p = 0.91). In contrast, the risk analysis for DCI, including 23,864 aSAH patients, showed an 11% relative risk reduction in DCI in males versus females (RR, 0.89; 95% CI, 0.81-0.97; p = 0.01). The functional outcome analysis (favorable vs. unfavorable), including 7739 aSAH patients, showed a tendency towards better functional outcomes in men than women; however, this did not reach statistical significance (RR, 1.02; 95% CI, 0.98-1.07; p = 0.34). Conclusions: In conclusion, the available data suggest that sex/gender may play a significant role in the risk of DCI in patients with aSAH, emphasizing the need for sex-specific management strategies.

Sex-specific extracerebral complications in patients with aneurysmal subarachnoid hemorrhage

Background

Extracerebral complications in patients with aneurysmal subarachnoid hemorrhage (aSAH) often occur during their stay at the neurocritical care unit (NCCU). Their influence on outcomes is poorly studied. The identification of sex-specific extracerebral complications in patients with aSAH and their impact on outcomes might aid more personalized monitoring and therapy strategies, aiming to improve outcomes.

Methods

Consecutive patients with aSAH admitted to the NCCU over a 6-year period were evaluated for the occurrence of extracerebral complications (according to prespecified criteria). Outcomes were assessed with the Glasgow Outcome Scale Extended (GOSE) at 3 months and dichotomized as favorable (GOSE 5-8) and unfavorable (GOSE 1-4). Sex-specific extracerebral complications and their impact on outcomes were investigated. Based on the results of the univariate analysis, a multivariate analysis with unfavorable outcomes or the occurrence of certain complications as dependent variables was performed.

Results

Overall, 343 patients were included. Most of them were women (63.6%), and they were older than men. Demographics, presence of comorbidities, radiological findings, severity of bleeding, and aneurysm-securing strategies were compared among the sexes. More women than men suffered from cardiac complications (p = 0.013) and infection (p = 0.048). Patients with unfavorable outcomes were more likely to suffer from cardiac (p < 0.001), respiratory (p < 0.001), hepatic/gastrointestinal (p = 0.023), and hematological (p = 0.021) complications. In the multivariable analysis, known factors including age, female sex, increasing number of comorbidities, increasing World Federation of Neurosurgical Societies (WFNS), and Fisher grading were expectedly associated with unfavorable outcomes. When adding complications to these models, these factors remained significant. However, when considering the complications, only pulmonary and cardiac complications remained independently associated with unfavorable outcomes.

Conclusion

Extracerebral complications after aSAH are frequent. Cardiac and pulmonary complications are independent predictors of unfavorable outcomes. Sex-specific extracerebral complications in patients with aSAH exist. Women suffered more frequently from cardiac and infectious complications potentially explaining the worse outcomes.

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.

Sex Differences in Cerebral Aneurysms and Subarachnoid Hemorrhage

Sex differences in cerebral aneurysm occurrence and characteristics have been well described. Although sex differences in outcomes following ischemic stroke have been identified, the effect of sex on outcomes following hemorrhagic stroke, and in particular, aneurysm treatment has been less studied. We describe the current state of knowledge regarding the impact of sex on treatment and outcomes of cerebral aneurysms. Although prior studies suggest that aneurysm prevalence and progression may be related to sex, we did not find clear evidence that outcomes following subarachnoid hemorrhage vary based on sex. Last, we identify areas for future research that could enhance understanding of the role sex plays in this context.

Sex-related differences of invasive therapy in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Sex-related differences in patients with aneurysmal subarachnoid hemorrhage (aSAH) exist. More females than males are affected. Aneurysm location is associated to sex. The relationship between sex and outcome, however, is unclear. Possible differences in management might influence the occurrence of primary and secondary brain injury and thus outcome. The study compares demographics, intensity of treatment, complications, and outcome among females and males with aSAH.

METHODS

All consecutive patients with aSAH admitted to the neurocritical care unit, University Hospital Zurich over a 5-year period were eligible in this retrospective study. Patients' characteristics, comorbidities, aSAH severity, frequency of vasospasm/delayed cerebral ischemia, frequency of invasive interventions, and 3-month outcome were compared by sex. Univariate analysis was performed with the data dichotomized by sex, and outcome. Multivariate analysis for prediction of outcomes was performed.

RESULTS

Three hundred forty-eight patients were enrolled (64% females). Women were older than men. Comorbidities, scores at admission, and treatment modality were comparable among males and females. Vasospasm and DCI occurred similarly among females and males. Interventions and frequency of intraarterial spasmolysis were comparable between sexes. In the multivariate analysis, increasing age, female sex, increasing comorbidities, WFNS and Fisher grade, and presence of delayed cerebral ischemia were predictors of unfavorable outcome when considering all patients. However, after excluding death as a possible outcome, sex did not remain a predictor of unfavorable outcome.

CONCLUSIONS

In the study population, women with aSAH might have present a worse outcome at 3 months. However, no differences by sex that might explain this difference were found in intensity of treatment and management.

Hippocampal Transcriptome Changes After Subarachnoid Hemorrhage in Mice

After subarachnoid hemorrhage (SAH), up to 95% of surviving patients suffer from post-SAH syndrome, which includes cognitive deficits with impaired memory, executive functions, and emotional disturbances. Although these long-term cognitive deficits are thought to result from damage to temporomesial-hippocampal areas, the underlying mechanisms remain unknown. To fill this gap in knowledge, we performed a systematic RNA sequencing screen of the hippocampus in a mouse model of SAH. SAH was induced by perforation of the circle of Willis in mice. Four days later, hippocampal RNA was obtained from SAH and control (sham perforation) mice. Next-generation RNA sequencing was used to determine differentially expressed genes in the whole bilateral hippocampi remote from the SAH bleeding site. Functional analyses and clustering tools were used to define molecular pathways. Differential gene expression analysis detected 642 upregulated and 398 downregulated genes (false discovery rate <0.10) in SAH compared to Control group. Functional analyses using IPA suite, Gene Ontology terms, REACTOME pathways, and MsigDB Hallmark gene set collections revealed suppression of oligodendrocytes/myelin related genes, and overexpression of genes related to complement system along with genes associated with innate and adaptive immunity, and extracellular matrix reorganization. Interferon regulatory factors, TGF-β1, and BMP were identified as major orchestrating elements in the hippocampal tissue response. The MEME-Suite identified binding motifs of Krüppel-like factors, zinc finger transcription factors, and interferon regulatory factors as overrepresented DNA promoter motifs. This study provides the first systematic gene and pathway database of the hippocampal response after SAH. Our findings suggest that damage of the entorhinal cortex by subarachnoid blood may remotely trigger specific hippocampal responses, which include suppression of oligodendrocyte function. Identification of these novel pathways may allow for development of new therapeutic approaches for post-SAH cognitive deficits.

Cerebrovascular disease in women

Cerebrovascular disease is a major cause of morbidity, mortality, and disability in women. The spectrum of disease differs between men and women, with women being particularly vulnerable to certain conditions, especially during specific periods of life such as pregnancy. There are several unique risk factors for cerebrovascular disease in women, and the influence of some traditional risk factors for stroke is stronger in women. Moreover, disparities persist in representation of women in clinical trials, acute intervention, and stroke outcomes. In this review, we aimed to explore the epidemiology, etiologies, and management of cerebrovascular disease in women, highlighting some of these differences and the growing need for sex-specific management guidelines and health policies.

Clinical analysis of young adult patients with ruptured intracranial aneurysms: a single-center study of 113 consecutive patients

OBJECTIVE

Intracranial aneurysm most frequently occurs in old aged patients; however, aneurysmal subarachnoid hemorrhage (SAH) has been occasionally reported in young adults. This study aimed to compare patients with intracranial aneurysms younger than 40 years with those ≥40 years and investigates the characteristics of their ruptured aneurysm.

METHODS

We retrospectively collected the data of 389 patients (103 patients aged 20 to 39 years; 286 patients aged above 40 years) who were treated for ruptured cerebral aneurysms between January 2008 and December 2018 at our institution.

RESULTS

The young adult patients were more often men and were smokers as compared to controls (63.1% vs. 39.2%, 40.5% vs. 36.0%, respectively). The young adult patients showed a tendency for lower Hunt and Hess grade, modified Fisher grade, less postoperative morbidity, and better clinical outcome. Aneurysm ruptures occurred most frequently in the anterior cerebral artery in both groups, but aneurysms ruptures in the internal carotid artery and posterior circulation was infrequent among young adult patients. The aneurysms in young adult patients were more often elongated or irregularly shaped (82.5% vs. 64.0%, respectively) and were significantly smaller (5.9 mm) than that in controls (6.8 mm).

CONCLUSIONS

Ruptured aneurysms of young adult patients have unique characteristics with regard to its preponderance in male smoker, elongated or irregular shape and relatively smaller size.

Sex differences in aneurysmal subarachnoid haemorrhage (aSAH): aneurysm characteristics, neurological complications, and outcome

BACKGROUND

Women are over-represented in aSAH cohorts, but whether their outcomes differ to men remains unclear. We examined if sex differences in neurological complications and aneurysm characteristics contributed to aSAH outcomes.

METHODS

In a retrospective cohort (2010-2016) of all aSAH cases across two hospital networks in Australia, information on severity, aneurysm characteristics and neurological complications (rebleed before/after treatment, postoperative stroke < 48 h, neurological infections, hydrocephalus, seizures, delayed cerebral ischemia [DCI], cerebral infarction) were extracted. We estimated sex differences in (1) complications and aneurysm characteristics using chi square/t-tests and (2) outcome at discharge (home, rehabilitation or death) using multinomial regression with and without propensity score matching on prestroke confounders.

RESULTS

Among 577 cases (69% women, 84% treated) aneurysm size was greater in men than women and DCI more common in women than men. In unadjusted log multinomial regression, women had marginally greater discharge to rehabilitation (RRR 1.15 95% CI 0.90-1.48) and similar likelihood of in-hospital death (RRR 1.02 95% CI 0.76-1.36) versus discharge home. Prestroke confounders (age, hypertension, smoking status) explained greater risk of death in women (rehabilitation RRR 1.13 95% CI 0.87-1.48; death RRR 0.75 95% CI 0.51-1.10). Neurological complications (DCI and hydrocephalus) were covariates explaining some of the greater risk for poor outcomes in women (rehabilitation RRR 0.87 95% CI 0.69-1.11; death RRR 0.80 95% CI 0.52-1.23). Results were consistent in propensity score matched models.

CONCLUSION

The marginally poorer outcome in women at discharge was partially attributable to prestroke confounders and complications. Improvements in managing complications could improve outcomes.

Delayed cerebral ischaemia in patients with aneurysmal subarachnoid haemorrhage: Functional outcome and long-term mortality

INTRODUCTION

Delayed cerebral ischaemia (DCI) is one of the most frequent complications of aneurysmal subarachnoid haemorrhage (aSAH). The purpose of the present retrospective cohort study of patients with aSAH was to identify the association between DCI, functional outcome and 4-year mortality.

METHODS

Patients admitted to the Neurointensive Care Unit at Rigshospitalet, Copenhagen, with aSAH from 1 January 2010, through 31 December 2013 were registered. Patients were categorized into 3 groups: (a) those with DCI, defined as either a decline in consciousness or focal neurological deficits lasting ≥1 hour without any other detectable cause, (b) those without DCI, or (c) those who were unassessable for DCI. Functional neurological outcome after 6 months, as measured by the modified Rankin Scale (mRS), was dichotomized into good (mRS 0-2) and poor (mRS 3-6). Kaplan-Meier survival curves were constructed, and incidence risk rates were calculated both to determine the association between DCI and mortality.

RESULTS

Four hundred ninety-two cases of aSAH were recorded in the study period. DCI occurred in 23% of all patients, corresponding to 33% of assessable patients. Patients without DCI had the best functional outcome (mRS) compared to patients with DCI and patients who were unassessable; furthermore, the latter had worse outcomes than patients with DCI. Patients diagnosed with DCI had significantly higher mortality than those without DCI, even ignoring the first 14 days after admission.

CONCLUSION

DCI may be associated with both short- and long-term morbidity and mortality in patients with aSAH.

Risk Factors for the Rupture of Bifurcation Intracranial Aneurysms Using CT Angiography

PURPOSE

To investigate the clinical and morphological characteristics in relation to risk of bifurcation intracranial aneurysm rupture.

MATERIALS AND METHODS

Data from 202 consecutive patients with 219 bifurcation aneurysms (129 ruptured and 90 unruptured) managed at the authors' facility between August 2011 and July 2014 were retrospectively reviewed. Based on their clinical records and CT angiographic findings, the ability of risk factors to predict aneurysm rupture was assessed using statistical methods.

RESULTS

Age, hypertension, diabetes mellitus, and cerebral atherosclerosis were negatively correlated with aneurysm rupture. Aneurysms located in the middle cerebral artery, daughter artery ratio, lateral angle ratio (LA ratio), and neck width were negatively correlated with rupture. Aneurysms located in the anterior communicating artery, irregularity, with daughter sac, depth, width, maximum size, aspect ratio (AR), depth-to-width ratio, and bottleneck factor were significantly and positively correlated with rupture. Binary logistic regression model revealed that irregular shape [odds ratio (OR) 6.598] and AR (OR 3.507) strongly increased the risk of bifurcation aneurysm rupture, while age (OR 0.434), cerebral atherosclerosis (OR 0.125), neck width (OR 0.771), and LA ratio (OR 0.267) were negatively correlated with rupture (p<0.05). Receiver operating characteristic analysis revealed the threshold values of AR and LA ratio to be 1.18 and 1.50, respectively.

CONCLUSION

Age (≥60 yr), cerebral atherosclerosis, and aneurysms with a larger neck width and larger LA ratio are protective factors against bifurcation aneurysm rupture. An aneurysm with an irregular shape and an increased AR reflect the greater likelihood of a rupture.

Sex differences in aneurysm morphologies and clinical outcomes in ruptured anterior communicating artery aneurysms: a retrospective study

OBJECTIVES

Ruptured anterior communicating artery (ACoA) aneurysms occur more frequently in men. The purpose of the study was to investigate sex difference in aneurysm morphologies and clinical outcomes in patients with ruptured ACoA aneurysms.

SETTING

A tertiary referral hospital.

PARTICIPANTS

A total of 574 consecutive patients with ACoA aneurysms were admitted to our hospital from December 2007 to February 2015. In all, 474 patients (257 men and 217 women) with ruptured ACoA aneurysms were included in the study.

MAIN OUTCOME MEASURES

Aneurysm morphologies were measured using computed tomographic angiography and clinical outcomes were measured with Glasgow coma score at discharge.

RESULTS

The aneurysm sizes (p=0.001), aneurysm heights (p=0.011), size ratios (p<0.001), flow angles (p=0.047) and vessel angles (p=0.046) were larger in the male patients than in the females. The female patients more often had larger vessel sizes (p=0.002). Multivariate logistic analysis revealed that significant differences in aneurysm morphologies between men and women were aneurysm size (OR 1.1, 95% CI 1.0 to 1.3; p=0.036), aneurysm height (OR 0.8, 95% CI 0. to 0.9; p=0.006) and size ratio (OR 1.4, 95% CI 0.5 to 1.7; p=0.001). There were no statistically significant differences in the outcomes between men and women (OR 1.0, 95% CI 0.6 to 1.7, p=0.857).

CONCLUSIONS

The men were independently associated with larger aneurysm sizes, greater aneurysm heights and larger size ratios. Sex was not a risk factor for poor outcome in patients with ruptured ACoA aneurysms.

Relationship between Postmenopausal Estrogen Deficiency and Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is one of the most severe forms of stroke, which results from the rupture of a cerebral aneurysm. SAH is the only type of stroke with a female predominance, suggesting that reproductive factors may play a significant role in the etiology. Estrogen has important effects on vascular physiology and pathophysiology of cerebral aneurysm and SAH and, thus, potential therapeutic implications. There have been growing bodies of epidemiological and experimental studies which support the hypothesis of a significant relationship between estrogen deficiency and cerebral aneurysm formation with subsequent SAH. This hypothesis is the focus of this review as well as possible pathology-based therapeutics with regard to aspects of molecular pathophysiology, especially related to women's health.

Pattern of Cerebral Aneurysms in a Kenyan Population as Seen at an Urban Hospital

BACKGROUND

Intracranial aneurysms constitute a significant part of the caseload for any neurosurgical service. Despite the occurrence of intracranial aneurysms and the availability of advanced diagnostic tools and management options, there is a paucity of published data concerning aneurysm patterns in Kenya.

METHODS

This was a combined retrospective and prospective quantitative descriptive study. Following ethical approval, all patients with cerebral aneurysms seen on computed tomography angiography who presented at Nairobi Hospital between May 2010 and June 2014 were included. A standardized questionnaire was used to collect data on patient characteristics, indications for imaging, and radiologic findings. Analysis was carried out SPSS for Windows version 15.0.

RESULTS

The study included 121 patients with a female (71.9%) predominance; most (30.58%) of the patients were aged 50-59 years. There were 151 aneurysms observed, with 85.95% of patients having solitary aneurysms and 14.05% having multiple aneurysms; 82.1% of the aneurysms were located in the anterior circulation. Mean aneurysm size was 6.92 mm, mean neck diameter was 2.79 mm, and the range of diameter/neck ratio was 1-11.88 (mean 1.16). The rate of subarachnoid bleeding displayed an exponential increase with aneurysms 3 mm in size and appeared to plateau thereafter despite increasing aneurysm size. Most (78.8%) of the observed anterior communicating artery aneurysms were ruptured.

CONCLUSIONS

Most patients were postmenopausal women, who had a higher rate of aneurysms with an elevated risk of rupture for small aneurysms; this suggests that clinicians need to be more vigilant and have a higher index of suspicion in such patients with subtle clinical signs. This study revealed a pattern of aneurysms in accord with previous reports and is expected to serve as a basis for further research on aneurysm management, outcome, and prognostic indicators in the Kenyan population.

Epidemiological investigation of 264 sporadic cases of ruptured cerebral aneurysm at a single institution in southwest China

BACKGROUND

The purpose of this study was to investigate the epidemiology of sporadic ruptured cerebral aneurysm in the Chinese population.

METHODS

We retrospectively analyzed the medical records of 264 consecutive Chinese patients admitted to the Affiliated Hospital of Zunyi Medical University of Guizhou Province in Southwest China between December 2012 and March 2015 for spontaneous subarachnoid hemorrhage due to a ruptured cerebral artery aneurysm.

RESULTS

The study population comprised 171 females and 93 males with a median age of 50 (range 5-76) years. The female to male ratio was 1.84:1. For both males and females, aneurysm rupture was most common in the 40-49-year age group (34.5%). Most of the ruptured aneurysms were in the size range of 2-5 mm (47.2%), followed by 5-10 mm (43.8%). Ruptured aneurysms occurred most often in the posterior communicating artery (36.6%) or the anterior communicating artery (25.7%). There were more cases of anterior communicating artery aneurysm on the left side (53 [Left side]/16 [Right side]=3.31, P>0.001) and slightly more cases of posterior communicating artery aneurysm on the right side (54 [Right side]/44[Left side]=1.23, P<0.05).

CONCLUSION

This study provides valuable information on the epidemiology of ruptured cerebral aneurysm in the Chinese population.

Subarachnoid hemorrhage and the female sex: analysis of risk factors, aneurysm characteristics, and outcomes

OBJECT

The pathophysiology of aneurysmal subarachnoid hemorrhage (aSAH) is unclear. Sex may play a role in the outcome of patients with aSAH.

METHODS

The authors retrospectively identified 617 patients with aSAH (April 2005 to February 2010) and analyzed sex differences in risk factors (age, hypertension, smoking, alcohol consumption, and family history), admission-related factors (World Federation of Neurosurgical Societies grade and admission delay), aneurysm characteristics (site, side, location, and multiplicity), and outcomes (treatment modalities [coiling/clipping/both/conservative], complications [vasospasm and hydrocephalus], length of stay, and modified Rankin Scale score at 3 months).

RESULTS

The female patients with aSAH were older than the male patients (mean age 56.6 vs 51.9 years, respectively, p < 0.001), and more women than men were ≥ 55 years old (56.2% vs 40.4%, respectively, p < 0.001). Women exhibited higher rates of bilateral (6.8% vs 2.6%, respectively, p < 0.05), multiple (11.5% vs 5.2%, respectively, p < 0.05), and internal carotid artery (ICA) (36.9% vs 17.5%, respectively, p < 0.001) aneurysms and a lower rate of anterior cerebral artery aneurysms (26.3% vs 44.8%, respectively, p < 0.001) than the men, but no side differences were noted. There were no sex differences in risk factors, admission-related factors, or outcome measures. For both sexes, outcomes varied according to aneurysm location, with odds ratios for a poor outcome of 1.62 (95% CI 0.91-2.86, p = 0.1) for middle cerebral artery, 2.41 (95% CI 1.29-4.51, p = 0.01) for ICA, and 2.41 (95% CI 1.29-4.51, p = 0.006) for posterior circulation aneurysms compared with those for anterior cerebral artery aneurysms. The odds ratio for poor outcome (modified Rankin Scale score of 4-6) in women compared with men after adjusting for significant prognostic factors was 0.71 (95% CI 0.45-1.11, p > 0.05).

CONCLUSIONS

The overall outcomes after aSAH between women and men are similar.

An analysis of 1256 cases of sporadic ruptured cerebral aneurysm in a single Chinese institution

BACKGROUND

To review the epidemiology of sporadic ruptured cerebral aneurysm.

METHODS

This is a retrospective study of consecutive 1256 Chinese patients between January 2006 and January 2013, who were admitted to the Second Hospital of Hebei Medical University, China, for spontaneous subarachnoid hemorrhage due to a rupture of cerebral artery aneurysm. In 288 males and 478 females, the size of aneurysms was measured by a neuroradiologist on DSA. In 123 males and 184 females, the size of the ruptured aneurysms was not measured. The remaining patients, with 61 males and 122 females, had multiple aneurysms, and the medical record could not reliably determine the specific aneurysm responsible for the rupture.

RESULTS

In total there were 784 females and 472 males with a female/male ratio of 1.66. The female/male ratio was down to 0.50 for patients younger than 35 yrs. For both males and females, aneurysm rupture was most common during the age of 50-59 yrs. Ruptured aneurysms were mostly of 2 mm-5 mm in size (47.1%), followed by 5 mm-10 mm (39.7%). Ruptured single cerebral aneurysm occurred in anterior circulation in 95.0% of the cases, with 5.0% occurred in posterior circulation. Ruptured aneurysm most commonly occurred at posterior communicating artery (34.9%) and anterior communicating artery (29.5%). 183 cases (14.6%) had multiple aneurysms.

CONCLUSIONS

With younger patients, there is a male predominance in our series. Ninety percent of patients have ruptured aneurysms less than 10 mm in size.

Prevalence of unruptured intracranial aneurysms in healthy asymptomatic Japanese adults: differences in gender and age

BACKGROUND

We aimed to assess the prevalence of unruptured intracranial aneurysms (UIAs) in healthy asymptomatic adults, and investigate the differences in incidence due to gender and age in Japan.

METHODS

Magnetic resonance angiography (MRA) results of healthy asymptomatic adults who underwent the procedure for examination of the brain, from April 2010 to March 2012, were retrospectively examined. Patients with a history of ruptured aneurysm and UIAs were excluded. UIAs greater than 2.0 mm in size were counted. In accordance with these criteria, 8,696 people with a mean age of 52.2±9.5 years were examined, and 37.4 % of these individuals were women.

RESULTS

The overall prevalence of UIAs was 3.2 %. The prevalence in women was higher than that in men (4.4 % versus 2.5 %, OR, 1.81; 95% CI, 1.4 to 2.31). The prevalence increased with age in both genders. In under 49 years, the prevalence in women and men were 2.7 % and 1.9 %, respectively, with no significant differences (OR, 1.47; CI, 0.91 to 2.37). In over 50 years, the prevalence in women was higher than that in men (5.4 % versus 2.8 %, OR, 2.01; CI, 1.52–2.67). There were significant differences in the locations of UIAs by gender (P <0.001); Internal carotid artery was more frequent in women, whereas anterior cerebral artery and middle cerebral artery were more common inmen.

CONCLUSIONS

This study provides etiological data on the prevalence of UIAs in healthy asymptomatic Japanese adults, and may be useful in determining therapeutic managements for UIAs.

Health-related quality of life at median 12 months after aneurysmal subarachnoid hemorrhage, measured with EuroQoL-5D

BACKGROUND

A measurement of quality of life (QoL) should cover the important aspects of daily life and be easy to perform. Ease of performance is especially important for patients with spontaneous subarachnoid haemorrhage (SAH), since fatigue and cognitive disabilities are known sequeles. EuroQoL (EQ-5D) is a preference-based instrument measuring QoL, based on self-reported health status in five dimensions: Mobility, Self-Care, Usual Activities, Pain/Discomfort and Anxiety/Depression. In the present study EuroQoL was used in patients with aneurysmal SAH (aSAH) in comparison with a Swedish reference population. We also determined the extent to which demographic characteristics and clinical parameters predicted outcome.

METHODS

Seven hundred fifty-five patients with aSAH were studied after a median 12 months. The proportion of patients in the best QoL category for each dimension was compared with the corresponding proportion in an age matched reference population. Disease severity was measured using the World Federation of Neurosurgical Societies' SAH grading system and the Fisher scale. The extent to which demographic and clinical factors predicted outcome was evaluated using linear regression.

RESULTS

Aneurysmal SAH patients generally had a worse QoL compared with the reference population, in all five dimensions of EQ-5D. In the patient population, disease severity predicted worse outcome in all five dimensions. Female gender and surgery as treatment method (in the case of anterior aneurysms) predicted worse outcome in Usual Activities and Anxiety/Depression.

CONCLUSION

The nature of the sequeles after SAH depends on severity of disease, gender and treatment method. These factors should be more emphasised in planning rehabilitation.

Morphological and hemodynamic analysis of mirror posterior communicating artery aneurysms

BACKGROUND AND PURPOSE

Hemodynamic factors are commonly believed to play an important role in the pathogenesis, progression, and rupture of cerebral aneurysms. In this study, we aimed to identify significant hemodynamic and morphological parameters that discriminate intracranial aneurysm rupture status using 3-dimensional-angiography and computational fluid dynamics technology.

MATERIALS AND METHODS

3D-DSA was performed in 8 patients with mirror posterior communicating artery aneurysms (Pcom-MANs). Each pair was divided into ruptured and unruptured groups. Five morphological and three hemodynamic parameters were evaluated for significance with respect to rupture.

RESULTS

The normalized mean wall shear stress (WSS) of the aneurysm sac in the ruptured group was significantly lower than that in the unruptured group (0.52±0.20 versus 0.81±0.21, P = .012). The percentage of the low WSS area in the ruptured group was higher than that in the unruptured group (4.11±4.66% versus 0.02±0.06%, P = .018). The AR was 1.04±0.21 in the ruptured group, which was significantly higher than 0.70±0.17 in the unruptured group (P = .012). By contrast, parameters that had no significant differences between the two groups were OSI (P = .674), aneurysm size (P = .327), size ratio (P = .779), vessel angle (P = 1.000) and aneurysm inclination angle (P = 1.000).

CONCLUSIONS

Pcom-MANs may be a useful disease model to investigate possible causes of aneurysm rupture. The ruptured aneurysms manifested lower WSS, higher percentage of low WSS area, and higher AR, compared with the unruptured one. And hemodynamics is as important as morphology in discriminating aneurysm rupture status.

Gender differences in cerebral aneurysm location

Background and Purpose: A limited number of studies consisting predominantly of ruptured aneurysms have looked at differences in anatomical distribution of aneurysms between male and females. Unlike all other causes of stroke, subarachnoid hemorrhages (SAH) occur more often in women and are thought to be a result of both hormonal influences and variation in wall shear stress. This paper retrospectively looks at a cohort of largely unruptured intracranial aneurysms to determine if there exists a gender discrepancy in the anatomic distribution of cerebral aneurysms. Methods: A retrospective review of consecutive patients with ruptured and unruptured intradural saccular cerebral aneurysms treated endovascularly was performed. Results: Six hundred eighty-two aneurysms were treated. Seventy-two percentage of the patients were women and 27% of patients presented with SAH. Among women, most aneurysms were located along the ICA (54%) while men the ACA (29%, compared to 15% in women), a discrepancy evident in both unruptured and ruptured groups. Females tended to present later in life (59 vs. 55 years), with multiple aneurysms (11 vs. 6% in men), and with SAH (28 vs. 23% in men) – the majority of these ruptured aneurysms were located at the ICA (42%), while men at the ACA (47%). Additionally, the majority (68%) of ruptured ICA aneurysms were PCOM. Conclusion: Understanding the natural history of aneurysms is imperative in treating incidentally found aneurysms. Significant differences exist between the genders in relation to aneurysm location, the most pronounced at the ICA and ACA. Previously described hormonal and hemodynamic theories behind cerebral aneurysm pathogenesis seem like plausible reasons to explain these differences.

Analysis of Nonmodifiable Risk Factors for Intracranial Aneurysm Rupture in a Large, Retrospective Cohort

Background:

The risk factors predictive of intracranial aneurysm rupture remain incompletely defined.

Objective:

To examine the association between various nonmodifiable risk factors and aneurysm rupture in a large cohort of patients evaluated at a single institution.

Methods:

A retrospective analysis of patients admitted to a cerebrovascular facility between January 2006 and 2010 with a primary diagnosis of cerebral aneurysm. Aneurysms were divided into 2 groups: unruptured or ruptured. The dome diameter, aspect ratio (AR), location, sidedness, neck morphology, and multiplicity were entered into a central database. A full model was constructed, and a systematic removal of the least significant variables was performed in a sequential fashion until only those variables reaching significance remained.

Results:

We identified 2347 patients harboring 5134 individual aneurysms, of which 34.90% were ruptured and 65.09% were unruptured. On admission, 25.89% of aneurysms with a dome diameter &lt;10 mm and 58.33% of aneurysms with a dome &gt;10 mm were ruptured (P &lt; .001). Of aneurysms with an AR &gt;1.6, 52.44% presented following a rupture (P &lt; .001). The highest incidence of rupture (69.21%) was observed in aneurysms with an AR &gt;1.6, dome diameter &lt;10 mm, and a deviated neck. Deviated neck-type aneurysms had a significantly greater incidence of rupture than classical necktype aneurysms (P &lt; .001).

Conclusion:

An AR &gt;1.6, dome diameter &gt;10 mm, a deviated neck, and right-sidedness are independently associated with aneurysm rupture.

Small Unruptured Intracranial Aneurysm Verification Study

Background and Purpose— The natural history and optimal management of incidentally found small unruptured aneurysms <5 mm in size remain unclear. A prospective study was conducted to determine the optimal management for incidentally found small unruptured aneurysms.

Methods— From September 2000 to January, 2004, 540 aneurysms (446 patients) were registered. Four hundred forty-eight unruptured aneurysms <5 mm in size (374 patients) have been followed up for a mean of 41.0 months (1306.5 person-years) to date. We calculated the average annual rupture rate of small unruptured aneurysms and also investigated risk factors that contribute to rupture and enlargement of these aneurysms.

Results— The average annual risks of rupture associated with small unruptured aneurysms were 0.54% overall, 0.34% for single aneurysms, and 0.95% for multiple aneurysms. Patient <50 years of age ( P =0.046; hazard ratio, 5.23; 95% CI, 1.03 to 26.52), aneurysm diameter of ≥4.0 mm ( P =0.023; hazard ratio, 5.86; 95% CI, 1.27 to 26.95), hypertension ( P =0.023; hazard ratio, 7.93; 95% CI, 1.33 to 47.42), and aneurysm multiplicity ( P =0.0048; hazard ratio, 4.87; 95% CI, 1.62 to 14.65) were found to be significant predictive factors for rupture of small aneurysms.

Conclusions— The annual rupture rate associated with small unruptured aneurysms is quite low. Careful attention should be paid to the treatment indications for single-type unruptured aneurysms <5 mm. If the patient is <50 years of age, has hypertension, and multiple aneurysms with diameters of ≥4 mm, treatment should be considered to prevent future aneurysmal rupture.

The effect of aneurysm geometry on the intra-aneurysmal flow condition

Introduction

Various anatomical parameters affect on intra-aneurysmal hemodynamics. Nevertheless, how the shapes of real patient aneurysms affect on their intra-aneurysmal hemodynamics remains unanswered.

Methods

Quantitative computational fluid dynamics simulation was conducted using eight patients’ angiograms of internal carotid artery–ophthalmic artery aneurysms. The mean size of the intracranial aneurysms was 11.5 mm (range 5.8 to 19.9 mm). Intra-aneurysmal blood flow velocity and wall shear stress (WSS) were collected from three measurement planes in each aneurysm dome. The correlation coefficients (r) were obtained between hemodynamic values (flow velocity and WSS) and the following anatomical parameters: averaged dimension of aneurysm dome, the largest aneurysm dome dimension, aspect ratio, and dome–neck ratio.

Results

Negative linear correlations were observed between the averaged dimension of aneurysm dome and intra-aneurysmal flow velocity (r = −0.735) and also WSS (r = −0.736). The largest dome diameter showed a negative correlation with intra-aneurysmal flow velocity (r = −0.731) and WSS (r = −0.496). The aspect ratio demonstrated a weak negative correlation with the intra-aneurysmal flow velocity (r = −0.381) and WSS (r = −0.501). A clear negative correlation was seen between the intra-aneurysmal flow velocity and the dome–neck ratio (r = −0.708). A weak negative correlation is observed between the intra-aneurysmal WSS and the dome–neck ratio (r = −0.392).

Conclusion

The aneurysm dome size showed a negative linear correlation with intra-aneurysmal flow velocity and WSS. Wide-necked aneurysm geometry was associated with faster intra-aneurysmal flow velocity.