Risk of Rupture of an Intracranial Aneurysm Based on Patient Characteristics

Sequential rupture of two concomitant cerebral aneurysms

The diagnosis of multiple cerebral aneurysms in patients with a spontaneous aneurysmal subarachnoid haemorrhage is not uncommon. The incidence of rupture from a second aneurysm, whilst the patient is recovering from a first bleed is however extremely rare. We report a 21-year-old female with a WFNS grade 1 subarachnoid haemorrhage secondary to a ruptured 5mm right posterior communicating artery aneurysm which was secured with clipping. Sixteen days later, whilst an in-patient, she suffered a second SAH from a left anterior choroidal artery aneurysm which was subsequently coiled. Comparison of digital subtraction angiography showed an almost doubling of the aneurysm from 2.7x2 mm to 4.4x2.3 mm. We review the literature of previously reported simultaneous and sequential aneurysmal subarachnoid haemorrhage and add to the sparse literature on this rare phenomena.

Prevalence of unruptured intracranial aneurysms (UIAs) examined in the trauma population

BACKGROUND

Previous data on the prevalence of unruptured intracranial aneurysms (UIAs) vary widely, and studies based on these data are plagued with unintentional bias. Accurate prevalence data are paramount for any physician who counsels patients with intracranial aneurysms on rupture risk and treatment. We therefore sought to determine a more accurate number for the true prevalence of UIAs.

METHODS

A retrospective chart review was conducted at a level 1 trauma center and tertiary care hospital in an urban setting between 2019 and 2020. Inclusion criteria included patients admitted with blunt trauma. Exclusion criteria included not having a head and neck CTA performed and read by an attending radiologist. All head and neck CTA radiology reads were reviewed for incidentally discovered UIAs. Subgroup analysis was performed by age group, race, and gender.

RESULTS

A total of 5978 out of 8999 patients met the inclusion criteria, and 54 patients with 58 total aneurysms were identified giving an overall prevalence of 0.9%. Subgroup analysis was performed for all age groups, genders, and racial groups.

CONCLUSION

The overall aneurysm prevalence was found to be 0.9% in this sample. This rate is lower than rates previously cited in the literature and those quoted in local practice. This finding has significant implications when attempting to understand average rupture risk. Further studies are needed to power more subgroup analyses to use a more personalized approach to understanding an individual's risk of rupture.

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.

Gadolinium-enhanced intracranial aneurysm wall imaging and risk of aneurysm growth and rupture: a multicentre longitudinal cohort study

OBJECTIVES

In patients with an unruptured intracranial aneurysm, gadolinium enhancement of the aneurysm wall is associated with growth and rupture. However, most previous studies did not have a longitudinal design and did not adjust for aneurysm size, which is the main predictor of aneurysm instability and the most important determinant of wall enhancement. We investigated whether aneurysm wall enhancement predicts aneurysm growth and rupture during follow-up and whether the predictive value was independent of aneurysm size.

MATERIALS AND METHODS

In this multicentre longitudinal cohort study, individual patient data were obtained from twelve international cohorts. Inclusion criteria were as follows: 18 years or older with ≥ 1 untreated unruptured intracranial aneurysm < 15 mm; gadolinium-enhanced aneurysm wall imaging and MRA at baseline; and MRA or rupture during follow-up. Patients were included between November 2012 and November 2019. We calculated crude hazard ratios with 95%CI of aneurysm wall enhancement for growth (≥ 1 mm increase) or rupture and adjusted for aneurysm size.

RESULTS

In 455 patients (mean age (SD), 60 (13) years; 323 (71%) women) with 559 aneurysms, growth or rupture occurred in 13/194 (6.7%) aneurysms with wall enhancement and in 9/365 (2.5%) aneurysms without enhancement (crude hazard ratio 3.1 [95%CI: 1.3-7.4], adjusted hazard ratio 1.4 [95%CI: 0.5-3.7]) with a median follow-up duration of 1.2 years.

CONCLUSIONS

Gadolinium enhancement of the aneurysm wall predicts aneurysm growth or rupture during short-term follow-up, but not independent of aneurysm size.

CLINICAL RELEVANCE STATEMENT

Gadolinium-enhanced aneurysm wall imaging is not recommended for short-term prediction of growth and rupture, since it appears to have no additional value to conventional predictors.

KEY POINTS

• Although aneurysm wall enhancement is associated with aneurysm instability in cross-sectional studies, it remains unknown whether it predicts risk of aneurysm growth or rupture in longitudinal studies. • Gadolinium enhancement of the aneurysm wall predicts aneurysm growth or rupture during short-term follow-up, but not when adjusting for aneurysm size. • While gadolinium-enhanced aneurysm wall imaging is not recommended for short-term prediction of growth and rupture, it may hold potential for aneurysms smaller than 7 mm.

Subarachnoid hemorrhage mimicking an acute migraine attack: A case report

Subarachnoid hemorrhage is a neurological emergency in which arterial blood accumulates in the subarachnoid space with cerebral aneurysmal rupture being the most common cause. Subarachnoid hemorrhage is often misdiagnosed in the emergency department and mortality rates range from 8% to 67%. It may be the manifestation of the chronicity of the migraine. The difference in severity or quality compared to previous headaches, and other symptoms, particularly neck stiffness, but also seizure, syncope, focal neurological deficit, and vomiting are the key factors differentiating subarachnoid hemorrhage from the migraine. We report a case of a 37-year-old female with a previous history of migraines who presented with acute onset of excruciating headaches in the occiput associated with nausea, vomiting, and photophobia in whom a non-contrast computed tomography scan of the head showed hyper-densities involving the bilateral cerebral cortical sulcus and Sylvian fissure and the cerebral angiography showed a complex aneurysm in anterior communicating artery.

The Role of Gut and Oral Microbiota in the Formation and Rupture of Intracranial Aneurysms: A Literature Review

In recent years, there has been a growing interest in the role of the microbiome in cardiovascular and cerebrovascular diseases. Emerging research highlights the potential role of the microbiome in intracranial aneurysm (IA) formation and rupture, particularly in relation to inflammation. In this review, we aim to explore the existing literature regarding the influence of the gut and oral microbiome on IA formation and rupture. In the first section, we provide background information, elucidating the connection between inflammation and aneurysm formation and presenting potential mechanisms of gut-brain interaction. Additionally, we explain the methods for microbiome analysis. The second section reviews existing studies that investigate the relationship between the gut and oral microbiome and IAs. We conclude with a prospective overview, highlighting the extent to which the microbiome is already therapeutically utilized in other fields. Furthermore, we address the challenges associated with the context of IAs that still need to be overcome.

Mean arterial pressure-aneurysm neck ratio predicts the rupture risk of intracranial aneurysm by reflecting pressure at the dome

Background and purpose

The unruptured intracranial aneurysm (UIA) has high disability and mortality rate after rupture, it is particularly important to assess the risk of UIA and to carry out individualized treatment. The objective of this research is to introduce a novel parameter to predict the rupture risk of UIA.

Methods

A total of 649 patients with 964 intracranial aneurysms in our center were enrolled. A novel parameter named mean arterial pressure-aneurysmal neck ratio (MAPN) was defined. Ten baseline clinical features and twelve aneurysm morphological characteristics were extracted to generate the MAPN model. The discriminatory performance of the MAPN model was compared with the PHASES score and the UCAS score.

Results

In hemodynamic analysis, MAPN was positively correlated with wall shear stress and aneurysm top pressure, with Pearson correlation coefficients of 0.887 and 0.791, respectively. The MAPN was larger in the ruptured group (36.62 ± 18.96 vs. 28.38 ± 14.58, P < 0.001). The area under the curve (AUC) of the MAPN was superior than the AUC of aspect ratio (AR) and the bottleneck factor (BN), they were 0.64 (P < 0.001; 95% CI, 0.588-0.692), 0.611 (P < 0.001; 95% CI, 0.559-0.663) and 0.607 (P < 0.001; 95% CI, 0.554-0.660), respectively. The MAPN model constructed by aneurysm size, aneurysm location, presence of secondary sacs and MAPN, demonstrated good discriminatory ability. The MAPN model exhibited superior performance compared with the UCAS score and the PHASES score (the AUC values were 0.799 [P < 0.001; 95% CI, 0.756-0.840], 0.763 [P < 0.001; 95% CI,0.719-0.807] and 0.741 [P < 0.001; 95% CI, 0.695-0.787], respectively; the sensitivities were 0.849, 0.758 and 0.753, respectively).

Conclusions

Research demonstrates the potential of MAPN to augment the clinical decision-making process for assessing the rupture risk of UIAs.

Optimal Cost-Effective Screening Strategy for Unruptured Intracranial Aneurysms in Female Smokers

BACKGROUND

The prevalence of intracranial aneurysms among female cigarette smokers was shown to be high in previous studies, yet the cost-effectiveness of screening them has never been explored.

OBJECTIVE

To explore the most cost-effective screening strategy for female smokers.

METHODS

A decision analytical study was performed with a Markov model to compare different screening strategies with no screening and to explore the most optimal screening strategy for female smokers. Input data for the model were extracted from literature. A single screening at different ages and multiple screening every 15 years, 10 years, 5 years, and 2 years were performed for female smokers in different age ranges. Deterministic and probabilistic sensitivity analyses were performed to evaluate the robustness of the model. Finally, value of information analysis was performed to investigate the value of collecting additional data.

RESULTS

Screening female smokers for unruptured intracranial aneurysm is cost-effective. All screening strategies yield extra quality-adjusted life years. Screening at younger age brings more health benefit at lower cost. Frequent screening strategies decrease rupture rate of aneurysms more with higher costs per quality-adjusted life year. Screening after age 70 years and frequent screening (every 2 years) after age 60 years is not optimal. Among all the parameters in the model, collecting additional data on utility of the unscreened population would be most valuable.

CONCLUSION

Screening female smokers for intracranial aneurysms once at younger age is most optimal. However, in clinical practice, the duration and intensity of exposure to cigarettes should be taken into consideration.

A numerical investigation of the mechanics of intracranial aneurysms walls: Assessing the influence of tissue hyperelastic laws and heterogeneous properties on the stress and stretch fields

Numerical simulations have been extensively used in the past two decades for the study of intracranial aneurysms (IAs), a dangerous disease that occurs in the arteries that reach the brain and affect overall 3.2% of a population without comorbidity with up to 60% mortality rate, in case of rupture. The majority of those studies, though, assumed a rigid-wall model to simulate the blood flow. However, to also study the mechanics of IAs walls, it is important to assume a fluid-solid interaction (FSI) modeling. Progress towards more reliable FSI simulations is limited because FSI techniques pose severe numerical difficulties, but also due to scarce data on the mechanical behavior and material constants of IA tissue. Additionally, works that have investigated the impact of different wall modeling choices for patient-specific IAs geometries are a few and often with limited conclusions. Thus our present study investigated the effect of different modeling approaches to simulate the motion of an IA. We used three hyperelastic laws - the Yeoh law, the three-parameter Mooney-Rivlin law, and a Fung-like law with a single parameter - and two different ways of modeling the wall thickness and tissue mechanical properties - one assumed that both were uniform while the other accounted for the heterogeneity of the wall by using a "hemodynamics-driven" approach in which both thickness and material constants varied spatially with the cardiac-cycle-averaged hemodynamics. Pulsatile numerical simulations, with patient-specific vascular geometries harboring IAs, were carried out using the one-way fluid-solid interaction solution strategy implemented in solids4foam, an extension of OpenFOAM®, in which the blood flow is solved and applied as the driving force of the wall motion. We found that different wall morphology models yield smaller absolute differences in the mechanical response than different hyperelastic laws. Furthermore, the stretch levels of IAs walls were more sensitive to the hyperelastic and material constants than the stress. These findings could be used to guide modeling decisions on IA simulations, since the computational behavior of each law was different, for example, with the Yeoh law being the fastest to converge.

Cotinine levels influence the risk of rupture of brain aneurysms

Cotinine, the primary metabolite of nicotine, is currently regarded as the best biomarker of tobacco smoke exposure. We aim to assess whether cotinine levels are associated with (1) intracranial aneurysm and (2) intracranial aneurysm rupture.

METHODS

We performed a single-center case-control study. Cases were consecutive patients admitted with diagnosis of brain aneurysm (ruptured or unruptured). We randomly selected controls without intracranial aneurysm from the same source population that produced the cases. Smoking data were collected by questionnaire, and serum levels of cotinine were used as an objective measure of nicotine exposure. Logistic regression models were used to assess the relationship between cotinine levels and aneurysm rupture.

RESULTS

We included 86 patients with intracranial aneurysm and 96 controls. Smoking status (p < .001), cotinine levels (p = .009), and female sex (p = .006) were associated with diagnosis of intracranial aneurysm. In the multivariate analysis, controlling for sex, smoker status and age, levels of cotinine were independently associated with aneurysm rupture (OR 1.53, 95% CI 1.10-2.13, p = .012).

CONCLUSIONS

Our results suggest that high cotinine levels in smokers with brain aneurysm are significantly associated with high rupture risk, independently of smoker status, age, and sex.

Predicting the growth of middle cerebral artery bifurcation aneurysms using differences in the bifurcation angle and inflow coefficient

OBJECTIVE

Growing intracranial aneurysms (IAs) are prone to rupture. Previous cross-sectional studies using postrupture morphology have shown the morphological or hemodynamic features related to IA rupture. Yet, which morphological or hemodynamic differences of the prerupture status can predict the growth and rupture of smaller IAs remains unknown. The purpose of this longitudinal study was to investigate the effects of morphological features and the hemodynamic environment on the growth of IAs at middle cerebral artery (MCA) bifurcations during the follow-up period.

METHODS

One hundred two patients with MCA M1–2 bifurcation saccular IAs who underwent follow-up for more than 2 years at the authors’ institutions between 2011 and 2019 were retrospectively identified. During the follow-up period, cases involving growth of MCA IAs were assigned to the event group, and those with MCA IAs unchanged in size were assigned to the control group. The morphological parameters examined were aneurysmal neck length, dome height, aspect ratio and volume, M1 and M2 diameters and their ratio, and angle configurations among M1, M2, and the aneurysm. Hemodynamic parameters were flow rate and wall shear stress in M1, M2, and the aneurysm, including the aneurysmal inflow rate coefficient (AIRC), defined as the ratio of the aneurysmal inflow rate to the M1 flow rate. Those parameters were compared statistically between the two groups. Correlations between morphological and hemodynamic parameters were also examined.

RESULTS

Eighty-three of 102 patients were included: 25 with growing MCA IAs (event group) and 58 with stable MCA IAs (control group). The median patient age at initial diagnosis was 66.9 (IQR 59.8–72.3) years. The median follow-up period was 48.5 (IQR 36.5–65.6) months. Both patient age and the AIRC were significant independent predictors of the growth of MCA IAs. Moreover, the AIRC was strongly correlated with sharper bifurcation and inflow angles, as well as wider inclination angles between the M1 and M2 arteries.

CONCLUSIONS

The AIRC was a significant independent predictor of the growth of MCA IAs. Sharper bifurcation and inflow angles and wider inclination angles between the M1 and M2 arteries were correlated with the AIRC. MCA IAs with such a bifurcation configuration are more prone to grow and rupture.

Development of multiple intracranial aneurysms: beyond the common risk factors

OBJECTIVE

The prevalence of multiple intracranial aneurysms (MIAs) has increased over the last decades. Because MIAs have been identified as an independent risk factor for formation, growth, and rupture of intracranial aneurysms (IAs), a more profound understanding of the underlying pathophysiology of MIAs is needed. Therefore, the authors' extensive institutional aneurysm database was analyzed to elucidate differences between patients with a single IA (SIA) and those with MIAs.

METHODS

A total of 2446 patients seen with or for IAs at the University Hospital of Essen, Essen, Germany, from January 2003 to June 2016 were included in this retrospective cohort study and were separated into MIA and SIA subgroups. Patient data were screened for sociodemographic and radiographic parameters, preexisting medical conditions, and results of blood examinations. These parameters were analyzed for their correlations with MIAs and absolute number of IAs.

RESULTS

MIAs were identified in 853 (34.9%) patients. In multivariable analysis, MIAs were independently associated with female sex (p = 0.001), arterial hypertension (p = 0.023), tobacco abuse (p = 0.009), AB blood group (p = 0.010), and increased admission values for C-reactive protein (p = 0.006), mean corpuscular volume (p = 0.009), and total serum protein (p = 0.034), but not with diagnostic modality (3D vs 2D digital subtraction angiography, p = 0.912). Absolute number of IAs was independently associated with female sex (p < 0.001), arterial hypertension (p = 0.014), familial predisposition to IA (p = 0.015), tobacco consumption (p = 0.025), increased mean corpuscular volume (p = 0.002), and high platelet count (p = 0.007).

CONCLUSIONS

In this sizable consecutive series of patients with IAs, the authors confirmed the impact of common IA risk factors on the genesis of MIAs. In addition, specific hemorheological and hemocytological features may also contribute to the development of MIAs.

Computational fluid dynamic analysis of the initiation of cerebral aneurysms

OBJECTIVE

Relationships between aneurysm initiation and hemodynamic factors remain unclear since de novo aneurysms are rarely observed. Most previous computational fluid dynamics (CFD) studies have used artificially reproduced vessel geometries before aneurysm initiation for analysis. In this study, the authors investigated the hemodynamic factors related to aneurysm initiation by using angiographic images in patients with cerebral aneurysms taken before and after an aneurysm formation.

METHODS

The authors identified 10 cases of de novo aneurysms in patients who underwent follow-up examinations for existing cerebral aneurysms located at a different vessel. The authors then reconstructed the vessel geometry from the images that were taken before aneurysm initiation. In addition, 34 arterial locations without aneurysms were selected as control cases. Hemodynamic parameters acting on the arterial walls were calculated by CFD analysis.

RESULTS

In all de novo cases, the aneurysmal initiation area corresponded to the highest wall shear stress divergence (WSSD point), which indicated that there was a strong tensile force on the arterial wall at the initiation area. The other previously reported parameters did not show such correlations. Additionally, the pressure loss coefficient (PLc) was statistically significantly higher in the de novo cases (p < 0.01). The blood flow impact on the bifurcation apex, or the secondary flow accompanied by vortices, resulted in high tensile forces and high total pressure loss acting on the vessel wall.

CONCLUSIONS

Aneurysm initiation may be more likely in an area where both tensile forces acting on the vessel wall and total pressure loss are large.

Effect of Renin-Angiotensin-Aldosterone System Inhibitors on the Rupture Risk Among Hypertensive Patients With Intracranial Aneurysms

BACKGROUND

Mounting experimental evidence supports the concept that the RAAS (renin-angiotensin-aldosterone system) is involved in the pathogenesis of intracranial aneurysm rupture. However, whether RAAS inhibitors could reduce the rupture risk of intracranial aneurysms remains unclear.

METHODS

We performed a chart review of a multicenter, prospectively maintained database of 3044 hypertensive patients with intracranial aneurysms from 20 medical centers in China. The patients were separated into ruptured and unruptured groups. Univariable and multivariable logistical regression analyses were performed to determine the association between the use of RAAS inhibitors and the rupture risk. Sensitivity analyses and subgroup analyses were performed to verify the robustness of the results.

RESULTS

In multivariable analyses, female sex, passive smoking, uncontrolled, or unmonitored hypertension, use of over 2 antihypertensive medications, RAAS inhibitors use, antihyperglycemic agents use, hyperlipidemia, ischemic stroke, and aneurysmal location were independently associated with the rupture risk. The use of RAAS inhibitors was significantly associated with a reduced rupture risk compared with the use of non-RAAS inhibitors (odds ratio, 0.490 [95% CI, 0.402-0.597]; P=0.000). Compared with the use of non-RAAS inhibitors, the use of ACE (angiotensin-converting enzyme) inhibitors (odds ratio, 0.559 [95% CI, 0.442-0.709]; P=0.000) and use of ARBs (angiotensin receptor blockers; odds ratio, 0.414 [95% CI, 0.315-0.542]; P=0.000) were both significantly associated with a reduced rupture risk. The negative association of the rupture risk with RAAS inhibitors was consistent across 3 analyzed data and the predefined subgroups (including controlled hypertension).

CONCLUSIONS

The use of RAAS inhibitors was significantly associated with a decreased rupture risk independent of blood pressure control among hypertensive patients with intracranial aneurysms.

Risk factors for intracranial aneurysm rupture in pediatric patients

BACKGROUND

Intracranial aneurysm (IA) rupture in pediatric patients is a rare but fatal condition. Although risk factors for aneurysm rupture in adults have been well documented, they remain unknown in pediatric patients.

METHODS

Data for 94 pediatric patients with IAs were retrospectively analyzed. The patients were divided into ruptured and unruptured groups. Risk factors for aneurysm rupture were analyzed through univariable and multiple logistic regression analyses. Typical patients with risk factors were described.

RESULTS

Univariable analyses showed that the unruptured group had significantly higher percentages of giant aneurysms (43.2% vs 12.3%, P = 0.002), wide-neck aneurysms (67.6% vs 29.8%, P = 0.001), and aneurysms located in the internal carotid artery (40.5% vs 3.5%, P < 0.001), while the ruptured group had significantly higher percentages of patients younger than 5 years old (28.1% vs 5.4%, P = 0.013) and aneurysms located in the anterior cerebral artery (24.6% vs 5.4%, P = 0.032), posterior cerebral artery (14.0% vs 0%, P = 0.045), and distal arterial region (DAR) (46.8% vs 27.0%, P < 0.001). Multiple logistic regression analysis confirmed that age 0-5 years (OR = 6.844, P = 0.042) and IAs located in the DAR (OR = 4.162, P = 0.029) were independently related to an increased risk of rupture. Wide-necked aneurysms (OR = 0.235, P = 0.047) were independently associated with a lower risk of rupture.

CONCLUSIONS

Among pediatric patients, age younger than 5 years and lesions located in the DAR are independent risk factors for IA rupture, while an IA with a wide neck acts as a protective factor.

Dyslipidemia and rupture risk of intracranial aneurysms-a systematic review

Dyslipidemia is a well-established risk factor for coronary artery disease. However, the effect on cerebral artery disease, and more specifically the rupture risk of intracranial aneurysms, is unclear and has not yet been reviewed. We therefore performed a systematic review to investigate associations between different types of dyslipidemia and incidence of aneurysmal subarachnoid hemorrhage (aSAH). We used the MEDLINE, Embase, and Web of Science databases to identify clinical trials that compared the rupture risk among SAH patients with or without dyslipidemia. The risk of bias in each included study was evaluated using the Critical Appraisal Skills Program (CASP). Of 149 unique citations from the initial literature search, five clinical trials with a case-control design met our eligibility criteria. These studies compared aSAH patients to patients with unruptured aneurysms and found an overall inverse relationship between hypercholesterolemia and rupture risk of intracranial aneurysms. The quality assessment classified all included studies as high risk of bias. The evidence indicates that hypercholesterolemia is associated with a reduced rupture risk of intracranial aneurysms. However, it is not clear whether this relation is due to the dyslipidemic condition itself or the use of antihyperlipidemic medication.

Effects of Smoking on Short-Term and Long-Term Mortality after Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

The relationship between smoking and clinical outcomes after aneurysmal subarachnoid hemorrhage (aSAH) is poorly clarified, and current pieces of evidence are inconsistent. The purpose of this multicenter cohort study is therefore to explore the relationship between smoking and mortality as well as several complications after aSAH.

METHODS

Databases of patient records were from 4 tertiary hospitals. We assessed the impact of tobacco use and tobacco dose (categorized based on smoking index [SI]) on several complication and overall outcome variables. The primary outcome was mortality within the longest follow-up. Logistic models were used to investigate univariate and multivariate relationships between predictors and outcomes. We also developed a propensity score matching for smoking status by using all known confounders.

RESULTS

A total of 6,578 patients with aSAH were analyzed. Current smoking and former smoking did not show association with mortality within the longest follow-up (odds ratio [OR], 0.95, 95% confidence interval [CI]: 0.69-1.30, p = 0.726; OR, 0.66, 95% CI: 0.38-1.15, p = 0.139, respectively). In addition, patients who were current smokers showed an independent association with the decreased occurrence of hydrocephalus (OR, 0.60; 95% CI: 0.41-0.88; p = 0.009) after matching all known confounders. We also found moderate smoking (SI between 384 and 625) was associated with reduced mortality in hospital.

CONCLUSIONS

Our results indicated that in patients with aSAH, current smoking or former smoking was not associated with all-cause mortality up to 7-year follow-up.

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

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

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

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

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

Correlation between high hair cortisol level and intracranial aneurysm rupture

Measurement of cortisol in hair is a reliable method for determining long-term cortisol exposure reflecting chronic stress. Research using hair cortisol concentration has been limited to mainly cardiometabolic diseases. The association between hair cortisol concentration and aneurysmal rupture has not yet been studied. We aimed to investigate the relationship between the degree of chronic stress as measured by hair cortisol concentration and aneurysmal rupture.Sixty-eight patients diagnosed with intracranial aneurysms were included in this study (ruptured group, 30; unruptured group, 38). Hair cortisol was measured in 3-cm hair segments, reflecting roughly 3 months of hair growth. For a risk factor analysis, patient-specific factors and aneurysm-specific factors as well as hair cortisol concentration were investigated.Hair cortisol concentrations were significantly higher in the ruptured group than in the unruptured group (55.8 ± 22.0 ng/dL vs. 19.1 ± 6.4 ng/dL; P < .001). High hair cortisol concentration was found to be an independent risk factor for aneurysmal rupture (odds ratio [OR]: 2.245, 95% confidence interval [CI]: 1.825-2.753; P = .013). Additionally, a history of cerebrovascular disease was significantly associated with an increased risk of aneurysmal rupture (OR: 1.577, 95% CI: 1.099-2.262; P = .040).Based on our results, we suggest that chronic stress as measured by hair cortisol concentration could be an independent risk factor for intracranial aneurysmal rupture.

Tobacco use and age are associated with different morphologic features of anterior communicating artery aneurysms

We present a cohort of patients with anterior communicating artery (ACoA) aneurysms to investigate morphological characteristics and clinical factors associated with rupture of the aneurysms. 505 patients with ACoA aneurysms were identified at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016, with available CT angiography (CTA). Three-dimensional (3D) reconstructions were performed to evaluate aneurysmal morphologic features, including location, projection, irregularity, the presence of daughter dome, height, height/width ratio, and relationships between surrounding vessels. Patient risk factors assessed included patient age, sex, tobacco use, alcohol use, and family history of aneurysms and aneurysmal subarachnoid hemorrhage. Logistic regression was used to build a predictive ACoA score for rupture. Morphologic features associated with ruptured ACoA aneurysms were the presence of a daughter dome (OR 21.4, 95% CI 10.6-43.1), smaller neck diameter (OR 0.55, 95% CI 0.42-0.71), larger aspect ratio (OR 3.57, 95% CI 2.05-6.24), larger flow angle (OR 1.03, 95% CI 1.02-1.05), and smaller ipsilateral A2-ACoA angle (OR 0.98, 95% CI 0.97-1.00). Tobacco use was predominantly associated with morphological factors intrinsic to the aneurysm that were associated with rupture while younger age was also associated with morphologic features extrinsic to the aneurysm that were associated with rupture. The ACoA score had good predictive capacity for rupture with AUC = 0.92 using the 0.632 bootstrap cross-validation for correction of overfitting bias. Ruptured ACoA aneurysms were associated with morphological features that are simple to assess using a simple scoring system. Tobacco use and younger age were predominantly associated with intrinsic and extrinsic morphological features characteristic of rupture, respectively.

Intracranial aneurysm and coarctation of the aorta: prevalence in the current era

BACKGROUND

A 10% prevalence of intracranial aneurysms in patients with coarctation of the aorta has been described in a few studies. Our objective is to describe the rate of intracranial aneurysm detection in patients with coarctation of the aorta in the current era. We hypothesise that, with earlier detection and coarctation of the aorta intervention, the rate of intracranial aneurysm is lower than previously reported and screening imaging may only be warranted in older patients or patients with certain risk factors.

METHODS

This is a retrospective study of 102 patients aged 13 years and older with coarctation who underwent brain computed tomography angiography, magnetic resonance imaging (MRI), or magnetic resonance angiography between January, 2000 and February, 2018.

RESULTS

The median age of coarctation repair was 4.4 months (2 days-47 years) and the initial repair was primarily surgical (90.2%). There were 11 former smokers, 4 current smokers, and 13 patients with ongoing hypertension. Imaging modalities included computed tomography angiography (13.7%), MRI (41.2%), and magnetic resonance angiography (46.1%), performed at a median age of 33.3 years, 22.4 years, and 25 years, respectively. There were 42 studies performed for screening, 48 studies performed for neurologic symptoms, and 12 studies performed for both screening and symptoms. There were no intracranial aneurysms detected in this study.

CONCLUSIONS

These results suggest that the rate of intracranial aneurysms may be lower than previously reported and larger studies should explore the risk of intracranial aneurysms in coarctation of the aorta in the current era.

Location of intracranial aneurysms is the main factor associated with rupture in the ICAN population

BACKGROUND AND PURPOSE

The ever-growing availability of imaging led to increasing incidentally discovered unruptured intracranial aneurysms (UIAs). We leveraged machine-learning techniques and advanced statistical methods to provide new insights into rupture intracranial aneurysm (RIA) risks.

METHODS

We analysed the characteristics of 2505 patients with intracranial aneurysms (IA) discovered between 2016 and 2019. Baseline characteristics, familial history of IA, tobacco and alcohol consumption, pharmacological treatments before the IA diagnosis, cardiovascular risk factors and comorbidities, headaches, allergy and atopy, IA location, absolute IA size and adjusted size ratio (aSR) were analysed with a multivariable logistic regression (MLR) model. A random forest (RF) method globally assessed the risk factors and evaluated the predictive capacity of a multivariate model.

RESULTS

Among 994 patients with RIA (39.7%) and 1511 patients with UIA (60.3 %), the MLR showed that IA location appeared to be the most significant factor associated with RIA (OR, 95% CI: internal carotid artery, reference; middle cerebral artery, 2.72, 2.02-3.58; anterior cerebral artery, 4.99, 3.61-6.92; posterior circulation arteries, 6.05, 4.41-8.33). Size and aSR were not significant factors associated with RIA in the MLR model and antiplatelet-treatment intake patients were less likely to have RIA (OR: 0.74; 95% CI: 0.55-0.98). IA location, age, following by aSR were the best predictors of RIA using the RF model.

CONCLUSIONS

The location of IA is the most consistent parameter associated with RIA. The use of 'artificial intelligence' RF helps to re-evaluate the contribution and selection of each risk factor in the multivariate model.

Genome-wide association study of intracranial aneurysms identifies 17 risk loci and genetic overlap with clinical risk factors

Rupture of an intracranial aneurysm leads to subarachnoid hemorrhage, a severe type of stroke. To discover new risk loci and the genetic architecture of intracranial aneurysms, we performed a cross-ancestry, genome-wide association study in 10,754 cases and 306,882 controls of European and East Asian ancestry. We discovered 17 risk loci, 11 of which are new. We reveal a polygenic architecture and explain over half of the disease heritability. We show a high genetic correlation between ruptured and unruptured intracranial aneurysms. We also find a suggestive role for endothelial cells by using gene mapping and heritability enrichment. Drug-target enrichment shows pleiotropy between intracranial aneurysms and antiepileptic and sex hormone drugs, providing insights into intracranial aneurysm pathophysiology. Finally, genetic risks for smoking and high blood pressure, the two main clinical risk factors, play important roles in intracranial aneurysm risk, and drive most of the genetic correlation between intracranial aneurysms and other cerebrovascular traits.

Predicting the Poor Recovery Risk of Aneurysmal Subarachnoid Hemorrhage: Clinical Evaluation and Management Based on a New Predictive Nomogram

PURPOSE

To develop and validate a model for identifying the risk factors of poor recovery in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A prediction model was developed using training data obtained from 1577 aSAH patients from multiple centers. The patients were followed for 6 months on average and assessed using the modified Rankin Scale; patient information was collected with a prospective case report form. The least absolute shrinkage and selection operator regression were applied to optimize factor selection for the poor recovery risk model. Multivariable logistic regression, incorporating the factors selected in the previous step, was used for model predictions. Predictive ability and clinical effectiveness of the model were evaluated using C-index, receiver operating characteristic curve, and decision curve analysis. Internal validation was performed using the C-index, taking advantage of bootstrapping validation.

RESULTS

The predictors included household income per capita, hypertension, smoking, migraine within a week before onset, Glasgow Coma Scale at admission, average blood pressure at admission, modified Fisher score at admission, treatment method, and complications. Our newly developed model made satisfactory predictions; it had a C-index of 0.796 and an area under the receiver operating characteristic curve of 0.784. The decision curve analysis showed that the poor recovery nomogram was of clinical benefit when an intervention was decided at a poor recovery threshold between 2% and 50%. Internal validation revealed a C-index of 0.760.

CONCLUSION

Our findings indicate that the novel poor recovery nomogram may be conveniently used for risk prediction in aSAH patients. For patients with intracranial aneurysms, migraine needs to be vigilant. Quitting smoking and blood pressure management are also beneficial.

Management of unruptured incidentally found intracranial saccular aneurysms

Unruptured intracranial saccular aneurysms occur in 3-5% of the general population. As the use of diagnostic medical imaging has steadily increased over the past few decades with the increased availability of computed tomography (CT) and magnetic resonance imaging (MRI), so has the detection of incidental aneurysms. The management of an unruptured intracranial saccular aneurysm is challenging for both patients and physicians, as the decision to intervene must weigh the risk of rupture and resultant subarachnoid hemorrhage against the risk inherent to the surgical or endovascular procedure. The purpose of this paper is to provide an overview of factors to be considered in the decision to offer treatment for unruptured intracranial aneurysms in adults. In addition, we review aneurysm and patient characteristics that favor surgical clipping over endovascular intervention and vice versa. Finally, the authors propose a novel, simple, and clinically relevant algorithm for observation versus intervention in unruptured intracranial aneurysms based on the PHASES scoring system.

Aneurysmal subarachnoid hemorrhage in patients with migraine and tension headache: A cohort comparison study

Migraine headache is a common condition with an estimated lifetime prevalence of greater than 20%. While it is a well-established risk factor for cardiovascular disease and ischemic stroke, its association with subarachnoid hemorrhage is largely unexplored. We sought to compare the incidence of aneurysmal subarachnoid hemorrhage in a cohort of migraine patients with a cohort of patients with tension headache. A cohort comparison study utilizing the MarketScan insurance claims database compared patients diagnosed with migraine who were undergoing treatment with abortive or prophylactic pharmacotherapy (treatment cohort) and patients diagnosed with tension headache who had never been diagnosed with a migraine and who were naïve to migraine pharmacotherapy (control cohort). Patients with major pre-existing risk factors for aSAH were excluded from the study, and minor risk factors such as smoking status and hypertension were accounted for using coarsened exact matching (CEM) and subsequent cox proportional-hazards (CPH) regression. More than 679,000 patients (~125,000 treatment and ~ 550,000 control) with an average follow-up of more than three years were analyzed for aneurysmal subarachnoid hemorrhage. CPH regression on matched data showed that treated migraine patients had a significantly lower hazard of aneurysmal subarachnoid hemorrhage compared with tension headache patients (HR = 0.40, 95% CI: 0.19 - 0.86, p = 0.02). This large cohort comparison study, analyzing more than 679,000 patients, demonstrated that migraine patients undergoing pharmacologic treatment had a lower hazard of aneurysmal subarachnoid hemorrhage than patients diagnosed with tension headaches. Future work specifically focusing on migraine medications may identify the mechanisms underlying this association.

Stability Assessment of Intracranial Aneurysms Using Machine Learning Based on Clinical and Morphological Features

Machine learning (ML) as a novel approach could help clinicians address the challenge of accurate stability assessment of unruptured intracranial aneurysms (IAs). We developed multiple ML models for IA stability assessment and compare their performances. We enrolled 1897 consecutive patients with unstable (n = 528) and stable (n = 1539) IAs. Thirteen patient-specific clinical features and eighteen aneurysm morphological features were extracted to generate support vector machine (SVM), random forest (RF), and feed-forward artificial neural network (ANN) models. The discriminatory performances of the models were compared with statistical logistic regression (LR) model and the PHASES score in IA stability assessment. Based on the receiver operating characteristic (ROC) curve and area under the curve (AUC) values for each model in the test set, the AUC values for RF, SVM, and ANN were 0.850 (95% CI 0.806-0.893), 0.858 (95 %CI 0.816-0.900), and 0.867 (95% CI 0.828-0.906), demonstrating good discriminatory ability. All ML models exhibited superior performance compared with the statistical LR and the PHASES score (the AUC values were 0.830 and 0.589, respectively; RF versus PHASES, P < 0.001; RF versus LR, P = 0.038). Important features contributing to the stability discrimination included three clinical features (location, sidewall/bifurcation type, and presence of symptoms) and three morphological features (undulation index, height-width ratio, and irregularity). These findings demonstrate the potential of ML to augment the clinical decision-making process for IA stability assessment, which may enable more optimal management for patients with IAs in the future.

Definition and Prioritization of Data Elements for Cohort Studies and Clinical Trials on Patients with Unruptured Intracranial Aneurysms: Proposal of a Multidisciplinary Research Group

INTRODUCTION

Variability in usage and definition of data characteristics in previous cohort studies on unruptured intracranial aneurysms (UIA) complicated pooling and proper interpretation of these data. The aim of the National Institute of Health/National Institute of Neurological Disorders and Stroke UIA and Subarachnoid Hemorrhage (SAH) Common Data Elements (CDE) Project was to provide a common structure for data collection in future research on UIA and SAH.

METHODS

This paper describes the development and summarization of the recommendations of the working groups (WGs) on UIAs, which consisted of an international and multidisciplinary panel of cerebrovascular specialists on research and treatment of UIAs. Consensus recommendations were developed by review of previously published CDEs for other neurological diseases and the literature on UIAs. Recommendations for CDEs were classified by priority into 'Core,' 'Supplemental-Highly Recommended,' 'Supplemental,' and 'Exploratory.'

RESULTS

Ninety-one CDEs were compiled; 69 were newly created and 22 were existing CDEs. The CDEs were assigned to eight subcategories and were classified as Core (8), Supplemental-Highly Recommended (23), Supplemental (25), and Exploratory (35) elements. Additionally, the WG developed and agreed on a classification for aneurysm morphology.

CONCLUSION

The proposed CDEs have been distilled from a broad pool of characteristics, measures, or outcomes. The usage of these CDEs will facilitate pooling of data from cohort studies or clinical trials on patients with UIAs.

Population-specific modelling of between/within-subject flow variability in the carotid arteries of the elderly

Computational fluid dynamics models are increasingly proposed for assisting the diagnosis and management of vascular diseases. Ideally, patient-specific flow measurements are used to impose flow boundary conditions. When patient-specific flow measurements are unavailable, mean values of flow measurements across small cohorts are used as normative values. In reality, both the between-subjects and within-subject flow variabilities are large. Consequently, neither one-shot flow measurements nor mean values across a cohort are truly indicative of the flow regime in a given person. We develop models for both the between-subjects and within-subject variability of internal carotid flow. A log-linear mixed effects model is combined with a Gaussian process to model the between-subjects flow variability, while a lumped parameter model of cerebral autoregulation is used to model the within-subject flow variability in response to heart rate and blood pressure changes. The model parameters are identified from carotid ultrasound measurements in a cohort of 103 elderly volunteers. We use the models to study intracranial aneurysm flow in 54 subjects under rest and exercise and conclude that OSI, a common wall shear-stress derived quantity in vascular CFD studies, may be too sensitive to flow fluctuations to be a reliable biomarker.

Risk factors for preoperative seizures in pediatric patients with intracranial aneurysms

OBJECTIVE

Seizures are common complications following intracranial aneurysms and present a greater risk to pediatric patients than adults. Though the risk factors of seizures in adults with intracranial aneurysms have been well documented, the risk factors in pediatric patients remain unknown. The aim of this study was to evaluate the risk factors for preoperative seizures and the effect of the treatment approach on postoperative seizures in pediatric patients with intracranial aneurysms.

PATIENTS AND METHODS

The data of 64 pediatric patients (mean age 11.4 ± 5.7 years; 68.8 % of males) with intracranial aneurysms were retrospectively analyzed from January 2012 to April 2017. Comparisons were made between patients with preoperative seizures (case group) and those without (control group).

RESULTS

Twenty-four patients (37.5 %) had preoperative seizures, and 15 patients (23.4 %) had postoperative seizures. Multiple logistic regression analysis revealed that younger age (0-5 years), head trauma history, ruptured aneurysms, lobe hematomas, modified Fisher grade 3-4, giant aneurysms, pseudoaneurysms and distal arterial aneurysms were independently associated with the increased risk of preoperative seizures. Patients in the surgical and endovascular groups did not differ significantly in the rates of preoperative seizures or early postoperative seizures (within 1 month) (P > 0.05). However, a significantly lower incidence of late postoperative seizures (1-3 months and 3-6 months) was observed in the surgical group compared with the endovascular group (P < 0.05).

CONCLUSION

Pediatric patients with intracranial aneurysms are at high risk for seizures. Risk factors for preoperative seizures included younger age (0-5 years), head trauma history, lobe hematomas, modified Fisher grade 3-4, giant aneurysms, pseudoaneurysms and distal arterial aneurysms. Compared with the endovascular treatment, surgical intervention provided more benefits with regard to reducing the risk of late postoperative seizures.

Characteristics of Unruptured Compared to Ruptured Intracranial Aneurysms: A Multicenter Case-Control Study

BACKGROUND

Only a minority of intracranial aneurysms rupture to cause subarachnoid hemorrhage.

OBJECTIVE

To test the hypothesis that unruptured aneurysms have different characteristics and risk factor profiles compared to ruptured aneurysms.

METHODS

We recruited patients with unruptured aneurysms or aneurysmal subarachnoid hemorrhages at 22 UK hospitals between 2011 and 2014. Demographic, clinical, and imaging data were collected using standardized case report forms. We compared risk factors using multivariable logistic regression.

RESULTS

A total of 2334 patients (1729 with aneurysmal subarachnoid hemorrhage, 605 with unruptured aneurysms) were included (mean age 54.22 yr). In multivariable analyses, the following variables were independently associated with rupture status: black ethnicity (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.29-4.56, compared to white) and aneurysm location (anterior cerebral artery/anterior communicating artery [OR 3.21; 95% CI 2.34-4.40], posterior communicating artery [OR 3.92; 95% CI 2.67-5.74], or posterior circulation [OR 3.12; 95% CI 2.08-4.70], compared to middle cerebral artery). The following variables were inversely associated with rupture status: antihypertensive medication (OR 0.65; 95% CI 0.49-0.84), hypercholesterolemia (0.64 OR; 95% CI 0.48-0.85), aspirin use (OR 0.28; 95% CI 0.20-0.40), internal carotid artery location (OR 0.53; 95% CI 0.38-0.75), and aneurysm size (per mm increase; OR 0.76; 95% CI 0.69-0.84).

CONCLUSION

We show substantial differences in patient and aneurysm characteristics between ruptured and unruptured aneurysms. These findings support the hypothesis that different pathological mechanisms are involved in the formation of ruptured aneurysms and incidentally detected unruptured aneurysms. The potential protective effect of aspirin might justify randomized prevention trials in patients with unruptured aneurysms.

Morphological parameters as factors of 12-month neurological worsening in surgical treatment of patients with unruptured saccular intracranial aneurysms: importance of size ratio

OBJECTIVE

It is well known that larger aneurysm size is a risk factor for poor outcome after surgical treatment of unruptured saccular intracranial aneurysms (USIAs). However, the authors have occasionally observed poor outcome in the surgical treatment of small USIAs and hypothesized that size ratio has a negative impact on outcome. The aim of this paper was to investigate the influence of size ratio on outcome in the surgical treatment of USIAs.

METHODS

Prospectively collected clinical and radiological data of 683 consecutive patients harboring 683 surgically treated USIAs were evaluated. Dome-to-neck ratio was defined as the ratio of the maximum width of the aneurysm to the average neck diameter. The aspect ratio was defined as the ratio of the maximum perpendicular height of the aneurysm to the average neck diameter of the aneurysm. The size ratio was calculated by dividing the maximum aneurysm diameter (height or width, mm) by the average parent artery diameter (mm). Neurological worsening was defined as an increase in modified Rankin Scale score of 1 or more points at 12 months. Clinical and radiological variables were compared between patients with and without neurological worsening.

RESULTS

The median patient age was 64 years (IQR 56-71 years), and 528 (77%) patients were female. The median maximum size, dome-to-neck ratio, aspect ratio, and size ratio were 4.7 mm (IQR 3.6-6.7 mm), 1.2 (IQR 1.0-1.4), 1.0 (IQR 0.76-1.3), and 1.9 (IQR 1.4-2.8), respectively. The size ratio was significantly correlated with maximum size (r = 0.83, p < 0.0001), dome-to-neck ratio (r = 0.69, p < 0.0001), and aspect ratio (r = 0.74, p < 0.0001). Multivariate logistic regression analysis showed that the specific USIA location (paraclinoid segment of the internal carotid artery: OR 6.2, 95% CI 2.6-15, p < 0.0001; and basilar artery: OR 8.4, 95% CI 2.8-25, p < 0.0001), size ratio (OR 1.3, 95% CI 1.1-1.6, p = 0.021), and postoperative ischemic lesion (OR 9.4, 95% CI 4.4-19, p < 0.0001) were associated with neurological worsening (n = 52, 7.6%), and other characteristics showed no significant differences.

CONCLUSIONS

The present study showed that size ratio, and not other morphological parameters, was a risk factor for 12-month neurological worsening in surgically treated patients with USIAs. The size ratio should be further studied in a large, prospective observational cohort to predict neurological worsening in the surgical treatment of USIAs.

Aneurysmal Subarachnoid Hemorrhage Associated with Small Aneurysms in Smokers and Women: A Retrospective Analysis

Background

Previous studies have shown low rupture rates for small aneurysms (<10 mm), suggesting that the risk of treatment could exceed the benefits. However, evidence has changed, showing crescent rates of aneurysmal subarachnoid hemorrhage (aSAH) associated with small aneurysms. We report trends in size, localization, clinical characteristics, and outcomes of intracranial aneurysms (IAs).

Methods

In this retrospective study, a total of 200 clinical histories of patients diagnosed with IAs over an 8-year period were analyzed. Variables considered included age, sex, tobacco consumption, morphological characteristics of the aneurysm, complications, vasospasm, and mortality. Qualitative variables were assessed by measurements of absolute and relative frequency. Smoking behavior, aneurysm size, and aneurysm rupture (AR) were compared using 1-way analysis of variance. Categorical variables were analyzed using Pearson's χ² test.

Results

The average age at presentation was 58 years. The average size of ruptured aneurysms in the general group was 2.5–7.5 mm, and AR was most common in women (76%) and in patients age 50–60 years (33%). The rate of vasospasm was 19%, and mortality was 37%. Smokers composed 32% of the cohort. Heavy smokers had a 57% rate of aSAH, with an average size of rupture of 5 mm. The most common location of aneurysms and AR was the AComA (33%).

Conclusions

Our results suggest increasing AR rates in aneurysms smaller than 10 mm. This trend is seen especially in individuals with heavy tobacco consumption and in women of perimenopausal age. Our findings show a tendency of AR in accordance with previous results and are expected to serve as basis for further research on aneurysm management.

Association of single and multiple aneurysms with tobacco abuse: an @neurIST risk analysis

OBJECTIVE

Although several studies have suggested that the incidence of intracranial aneurysms (IAs) is higher in smokers, the higher prevalence of subarachnoid hemorrhage (SAH) in smokers remains uncertain. It is unclear whether smoking additionally contributes to the formation of multiple aneurysms and the risk of rupture. The aim of this study was to determine whether smoking is associated with IA formation, multiplicity, or rupture.

METHODS

Patients from the prospective multicenter @neurIST database (n = 1410; 985 females [69.9%]) were reviewed for the presence of SAH, multiple aneurysms, and smoking status. The prevalence of smokers in the population of patients diagnosed with at least one IA was compared with that of smokers in the general population.

RESULTS

The proportion of smokers was higher in patients with IAs (56.2%) than in the reference population (51.4%; p < 0.001). A significant association of smoking with the presence of an IA was found throughout group comparisons (p = 0.01). The presence of multiple IAs was also significantly associated with smoking (p = 0.003). A trend was found between duration of smoking and the presence of multiple IAs (p = 0.057). However, the proportion of smokers among patients suffering SAH was similar to that of smokers among patients diagnosed with unruptured IAs (p = 0.48).

CONCLUSIONS

Smoking is strongly associated with IA formation. Once an IA is present, however, smoking does not appear to increase the risk of rupture compared with IAs in the nonsmoking population. The trend toward an association between duration of smoking and the presence of multiple IAs stresses the need for counseling patients with IAs regarding lifestyle modification.

Stress in Patients With (Un)ruptured Intracranial Aneurysms vs Population-Based Controls

BACKGROUND

Stress is associated with increased risk of stroke and might predispose to presence and rupture of intracranial aneurysms.

OBJECTIVE

To study the association of recent and lifelong stress with unruptured intracranial aneurysm (UIA) and aneurysmal subarachnoid hemorrhage (ASAH).

METHODS

In 227 UIA patients (mean age 61 ± 11 yr), 490 ASAH patients (59 ± 11 yr), and 775 controls (51 ± 15 yr) who were randomly retrieved from the general population, we assessed occurrence of major life events and perceived stress during the preceding 12 mo and the entire life. With multivariable logistic regression analysis, we calculated odds ratios (ORs) with 95% confidence intervals (95% CIs) for 4 categories of life events (financial-related, work-related, children-related, and death of family members) and for periods of perceived stress at home and at work (never vs sometimes, often, or always). We adjusted for sex, age, alcohol consumption, smoking, and hypertension.

RESULTS

The 4 categories of life events and perceived stress at work had ORs ranging from 0.4 to 1.7, of which financial stress for UIA was statistically significant (95% CI: 1.1-2.5). ORs for chronic perceived stress at home in the previous year were 4.3 (95% CI: 1.8-10.3) for UIA and 2.5 (1.2-5.5) for ASAH, and for lifelong exposure 5.7 (2.2-14.5) for UIA and 3.0 (1.3-7.0) for ASAH.

CONCLUSION

For some components of stress, there may be a relation with UIA and ASAH. The mechanisms underlying this relation should be unraveled; strategies to improve coping with stress may reduce the risk of rupture in patients with unruptured aneurysms.

Risk of ischaemic stroke in patients with migraine: a longitudinal follow-up study using a national sample cohort in South Korea

OBJECTIVE

Accumulating evidence has supported the association between migraine and stroke, but the causative association remains unclear. We aimed to investigate the risks of different types of stroke in patients with migraine.

DESIGN

A longitudinal follow-up study.

SETTING

Data collected from a national cohort between 2002 and 2013 by the South Korea Health Insurance Review and Assessment.

PARTICIPANTS

We extracted the data from patients with migraine (n=41 585) and 1:4 matched controls (n=1 66 340) and analysed the occurrence of ischaemic and haemorrhagic strokes. The migraine group included participants treated for migraine (International Classification of Disease-10 (ICD-10): G43)≥2 times. Haemorrhagic stroke (I60-I62) and ischaemic stroke (I63) were determined based on the admission histories. The crude and adjusted HRs were calculated using Cox proportional hazard models, and the 95% CI were determined. Subgroup analyses stratified by age and sex were also performed.

RESULTS

Higher rates of ischaemic stroke were observed in the migraine group (2.3% [964/41,585]) than in the control group (2.0% [3294/166 340], P<0.001). The adjusted HR for ischaemic stroke was 1.18 (95% CI=1.10 to 1.26) in the migraine group (P<0.001). Compared with control subjects, participants who reported migraine with aura and migraine without aura had increased adjusted HRs of 1.44 (95% CI=1.09 to 1.89) and 1.15 (95% CI=1.06 to 1.24), respectively, for ischaemic stroke, but no increased risk of haemorrhagic stroke. In our subgroup analysis, a strong association between migraine and ischaemic stroke was observed in young patients, specifically young women. The contribution of migraine to the occurrence of ischaemic stroke was also observed in middle-aged women and old women (each P<0.05). The risk of haemorrhagic stroke did not reach statistical significance in any age group.

CONCLUSION

Migraine is associated with an increased risk of ischaemic stroke, but not haemorrhagic stroke.

"Worst Headache of Life" in a Migraineur: Marginal Value of Emergency Department CT Scanning

PURPOSE

The ACR Appropriateness Criteria recommend performing noncontrast head CT (NCCT) for patients with sudden severe headache ("worst headache of life" [WHOL] or "thunderclap headache" [TCH]). The aim of this study was to assess the value of NCCT scanning in patients with known migraine histories and WHOL or TCH. The hypothesis was that there would be little utility in performing emergency department (ED) NCCT scans in migraineurs without other red flags, even if they had WHOL or TCH.

METHODS

The ED NCCT scans of all patients reporting WHOL or TCH who had established diagnoses of migraine were retrospectively reviewed over a 5-year period. Patients without known intracranial pathology, cancer, or immunocompromising disease or recent head trauma were included as the main study group. For comparison, patients with any of those factors were included as the comparison group. Scans were graded as (1) normal, (2) minor unimportant findings, (3) findings requiring intervention or follow-up, or (4) critical.

RESULTS

Two hundred twenty-four patients with the chief symptom of WHOL or TCH and a history of migraine who underwent ED NCCT were studied. In the main study group, no patients had grade 4 imaging findings (0%), one had a false-positive grade 3 finding (0.8%), and there were no cases of subarachnoid hemorrhage (0%). In the comparison group, six patients had grade 4 imaging findings (6.5%) and three had grade 3 findings (3.3%).

CONCLUSIONS

NCCT in known migraineurs with WHOL or TCH who do not have intracranial pathology, cancer, immunocompromising disease, or recent head trauma yielded no critical findings. Therefore, the value of scanning these patients is questionable.

Effect of premorbid hypertension control on outcome of patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

Hypertension is common in patients with aneurysmal subarachnoid hemorrhage (SAH). However, it is still unclear whether premorbid antihypertensive therapy can help to reduce the risk of severe aneurysmal bleeding. Therefore, this study aims to assess the effect of premorbid hypertension control on outcome of patients with aneurysmal SAH.

METHODS

We retrospectively reviewed the clinical data of patients with intracranial aneurysms admitted to our institution from February 2012 to December 2017. Based on premorbid hypertension history and use of antihypertensive agents, all patients with aneurysmal SAH were divided into antihypertensive group and uncontrolled group. Patient characteristics, imaging features, clinical complication, and outcome were analyzed between the two groups.

RESULTS

A total of 348 patients with ruptured aneurysms were included in this study. Compared to those with premorbid controlled hypertension, patients with premorbid uncontrolled hypertension presented worse clinical grade, with more severe aneurysmal SAH and more frequent intracerebral hematoma. Patients receiving a treatment for ACEI type or ARB type of drugs in the antihypertensive group suffered from less amount of aneurysmal bleeding, while patients with grade 3 hypertension in the uncontrolled group suffered from more amount of aneurysmal bleeding. Patients with premorbid controlled hypertension had a lower incidence of rebleeding, hydrocephalus, and cerebral vasospasm, and had a lower rate of disability and mortality.

CONCLUSIONS

Premorbid hypertension control is associated with favorable clinical outcome of patients with aneurysmal SAH. Besides, the ACEI type or ARB type of antihypertensive agents is associated with the less amount of bleeding after aneurysm rupture.

Number of Cigarettes Smoked Per Day, Smoking Index, and Intracranial Aneurysm Rupture: A Case-Control Study

Background and purpose

We aimed to investigate the effect of smoking on the risk of intracranial aneurysm (IA) rupture (IAR), specifically relationship between the number of cigarettes smoked per day (CPD) or smoking index and the risk of IAR.

Methods

We performed a single-center case-control study of consecutive patients evaluated or treated for IA at our institution from June 2015 to July 2016. Cases were patients with a ruptured IA. Two age- and sex-matched controls with an unruptured IA were included per case. Conditional logistic regression models were used to assess the relationship between both the CPD and smoking index (CPD × years of smoking) and IAR.

Results

The study population included 127 cases of IAR and 254 controls. The higher IAR risk was associated with cigarette smoking (both current and former) (OR, 2.3; 95% CI, 1.1-4.8; P = 0.029). Our subgroup analysis of smokers revealed a significant association between IAR risk and current smoking (OR, 2.8; 95% CI, 1.2-6.3; P = 0.012), current heavy smoking (CPD ≥ 20) (OR, 3.9; 95% CI, 1.4-11.0; P = 0.007), and a smoking index ≥800 (OR, 11.4; 95% CI, 2.3-24.5; P = 0.003). Former smoking was not significantly associated with IAR (OR, 1.1; 95% CI, 0.3-4.0; P = 0.929).

Conclusion

A dose-response relationship has been noted for intensity and duration of smoking consumption and increased risk of IAR. As smoking is modifiable, this finding is important to managing patients with IAs to quit or reduce smoking prior to life-threatening subarachnoid hemorrhage.

Quantitative proteomics analysis of differentially expressed proteins in ruptured and unruptured cerebral aneurysms by iTRAQ

The underlying pathophysiological mechanisms involved in cerebral aneurysms rupture remain unclear. This study was performed to investigate the differentially expressed proteins between ruptured and unruptured aneurysms using quantitative proteomics. The aneurysmal walls of six ruptured aneurysms and six unruptured aneurysms were collected during the surgical operation. The isobaric tags for relative and absolute quantification (iTRAQ) were used to identify the differentially expressed proteins and western blotting was performed to validate the expression of the proteins of interest. Bioinformatics analysis of the differentially expressed proteins was also performed using the KEGG database and GO database. Between ruptured and unruptured aneurysms, 169 proteins were found differently expressed, including 74 up-regulated proteins and 95 down-regulated proteins with a fold change ≥ 2 and p value ≤ .05. KEGG pathway analysis revealed that phagosome, focal adhesion and ECM-receptor interaction were the most common pathways involved in aneurysm rupture. In addition, the differential expressions of ITGB3, CRABP1 and S100A9 were validated by western blotting. Through the iTRAQ method, we found that inflammatory responses and cell-matrix interactions may play a significant role in the rupture of cerebral aneurysms. These findings provide a basis for better understanding of pathophysiological mechanisms associated with aneurysm rupture.

BIOLOGICAL SIGNIFICANCE

Intracranial aneurysm is the leading cause of life-threating subarachnoid hemorrhage which can cause 45% patients die within 30 days and severe morbidity in long-term survivors. With a high prevalence ranging from 1% to 5% in general population, cerebral aneurysm has become a widespread health hazard over past decades. Though great advances have been achieved in the diagnosis and treatment of this disease, the underlying pathophysiological mechanisms of aneurysm rupture remains undetermined and a lot of uncertainty still exists surrounding the treatment of unruptured cerebral aneurysms. Clarifying the mechanism associated with aneurysm rupture is important for estimating the rupture risk, as well as the development of new treatment strategy. Some previous studies have analyzed the molecular differences between ruptured and unruptured IAs at gene and mRNA levels, but further comprehensive proteomic studies are relatively rare. Here we performed a comparative proteomics study to investigate the differentially expressed proteins between ruptured IAs (RIAs) and unruptured IAs (UIAs). Results of our present study will provide more insights into the pathogenesis of aneurysm rupture at protein level. With a better understanding of pathophysiological mechanisms associated with aneurysm rupture, some noninvasive treatment strategies may be developed in the future.

[Standardization of Analysis Conditions and Prediction of Increase Prediction Using Blood Flow Analysis Software for Cerebral Aneurysms: Phantom Study and Clinical Study]

In recent years, reports have been made that predict the state of aneurysm by performing computational fluid dynamics (CFD) analysis using cerebral aneurysm blood flow analysis software. However, analysis results are not constant and there are various opinions, and it is conceivable that the image quality and analysis conditions of medical images used for CFD analysis are not standardized. In this study, CFD analysis of cerebral aneurysm phantom was performed, and image quality and analysis conditions were standardized. Then, we investigated whether increase of cerebral aneurysm and prediction of rupture are possible. From this study, stable results of wall shear stress analysis were obtained under slice thickness 1.0 mm or less, CT value 400 HU or more, reconstruction function as soft part function, image SD under 10 HU. In addition, as the size of the cerebral aneurysm became larger, wall shear stress tended to be lower, and the same tendency was shown also in clinical cases. Although CFD analysis using software dedicated to blood flow analysis did not reach the prediction of rupture, it can be evaluated based on the quantitative values for the aneurysm increase at the preceding stage and plays an important role in prediction there is a possibility.

Risk factors analysis of mirror aneurysms: A multi-center retrospective study based on clinical and demographic profile of patients

As a special subgroup of multiple intracranial aneurysms, mirror aneurysms are located bilaterally on the corresponding intracranial arteries. The current study sought to compare the clinical and demographic features of patients harboring mirror aneurysm, and to elucidate the corresponding risk factors. We performed a retrospective cohort study of 2641 intracranial aneurysms patients, who were admitted to our hospitals between January 2005 and June 2014. Patients were subdivided into three groups based on the inclusion criteria: (i) single (n=2250); (ii) non-mirror multiple (n=285); and (iii) mirror aneurysms (n=106). Clinical and demographic files of the three groups were collected and compared, and medical histories including stroke, hyperlipemia, hypertension, hyperglycemia, valvular heart disease were considered as potential risk factors. Potential morphological reasons for mirror cerebral aneurysms rupture, including aneurysms size, irregular walls and cerebral hemispheric dominance, were also compared. Our data showed that the male to female ratio of mirror aneurysms patients was 1:3.61, which was significantly different from that of single aneurysm (1:1.27) and multiple aneurysms (1:2.00). The prevalence of mirror aneurysms in women is higher than that in men (P<0.001). Older patients (especially 60-69 years old) also appear to be more vulnerable to mirror aneurysm than single aneurysm (P<0.001). In 84 mirror aneurysm patients the aneurysms were located on the internal carotid arteries (79.2%), most typically at the PComA or in the Cavernous ICA. Patients with medical history of hyperlipemia appear to have an increased risk of harboring mirror aneurysms. Larger aneurysm size and presence of an irregular aneurysm wall appear to be the morphological factors that predispose for mirror aneurysms rupture.