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

Computer Aided Intracranial Aneurysm Treatment Based on 2D/3D Mapping, Virtual Deployment and Online Distal Marker Detection

PURPOSE

To introduce a computational tool for peri-interventional intracranial aneurysm treatment guidance that maps preoperative planning information from simulation onto real-time X-Ray imaging.

METHODS

Preoperatively, multiple flow diverter (FD) devices are simulated based on the 3D mesh of the vessel to treat, to choose the optimal size and location. In the peri-operative stage, this 3D information is aligned and mapped to the continuous 2D-X-Ray scan feed from the operating room. The current flow diverter position in the 3D model is estimated by automatically detecting the distal FD marker locations and mapping them to the treated vessel. This allows to visually assess the possible outcome of releasing the device at the current position, and compare it with the one chosen pre-operatively.

RESULTS

The full pipeline was validated using retrospectively collected biplane images from four different patients (5 3D-DSA datasets in total). The distal FD marker detector obtained an average F1-score of 0.67 ( ± 0.224 ) in 412 2D-X-Ray scans. After aligning 3D-DSA + 2D-X-Ray datasets, the average difference between simulated and deployed positions was 0.832 mm ( ± 0.521 mm). Finally, we qualitatively show that the proposed approach is able to display the current location of the FD compared to their pre-operatively planned position.

CONCLUSIONS

The proposed method allows to support the FD deployment procedure by merging and presenting preoperative simulation information to the interventionists, aiding them to make more accurate and less risky decisions.

Mirror Aneurysms of the Pericallosal Artery Clipped During a Single Surgical Procedure: Case Report and Literature Review

Pericallosal artery aneurysms are rare, accounting for 2-9% of all intracranial aneurysms, and mirror aneurysms in this location are exceptionally uncommon, presenting unique surgical challenges due to their deep location and proximity to critical neurovascular structures. The aim of this case report is to describe the surgical management and successful outcome of a patient with mirror pericallosal artery aneurysms and to contribute insights into the clinical and surgical considerations for this rare condition. We report the case of a 71-year-old female with multiple cardiovascular and metabolic conditions, including hypertension and smoking-well-established risk factors for intracranial aneurysm formation and rupture. She presented with a Hunt and Hess grade II subarachnoid hemorrhage resulting in communicating internal hydrocephalus. Preoperative angiography revealed mirror aneurysms of the pericallosal artery. The patient underwent a left basal paramedian frontal craniotomy, during which a ruptured aneurysm on the right A2 segment and an unruptured aneurysm on the left A2 segment were identified. Both aneurysms were successfully clipped using curved Yasargil clips. Postoperative recovery was favorable, with no neurological deficits and stable imaging findings at a three-month follow-up. This case underscores the necessity for precise microsurgical intervention and a thorough understanding of pericallosal artery anatomy to manage such rare and challenging conditions effectively. The role of hyperlipidemia and statin use in intracranial aneurysm development remains debated and warrants further investigation. Our successful management of mirror pericallosal artery aneurysms contributes to the limited literature on this rare condition and highlights the importance of meticulous surgical techniques for favorable outcomes.

Advancements in Brain Aneurysm Management: Integrating Neuroanatomy, Physiopathology, and Neurosurgical Techniques

Brain aneurysms, characterized by abnormal bulging in blood vessels, pose significant risks if ruptured, necessitating precise neuroanatomical knowledge and advanced neurosurgical techniques for effective management. This article delves into the intricate neuroanatomy relevant to brain aneurysms, including the vascular structures and critical regions involved. It provides a comprehensive overview of the pathophysiology of aneurysm formation and progression. The discussion extends to modern neurosurgical approaches for treating brain aneurysms, such as microsurgical clipping, endovascular coiling, and flow diversion techniques. Emphasis is placed on preoperative planning, intraoperative navigation, and postoperative care, highlighting the importance of a multidisciplinary approach. By integrating neuroanatomical insights with cutting-edge surgical practices, this article aims to enhance the understanding and treatment outcomes of brain aneurysms.

Dl-3-n-Butylphthalide attenuates early brain injury and delayed neurological dysfunction by regulating NLRP3 inflammasome after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a severe neurological event lacking of effective therapy. Early brain injury (EBI) and delayed neurological dysfunction are important cause in the poor prognosis of patients with SAH. Nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3) inflammasome activation has been implicated in many inflammatory lesion pathogeneses including SAH. Dl-3-n-butylphthalide (NBP) has been reported to possess substantial anti-inflammatory properties, which is beneficial for various neurodegenerative diseases. However, the effect and molecular mechanisms of NBP on SAH have not been clearly identified. We designed this study to investigate the effect of NBP against EBI and delayed neurological dysfunction after SAH and to reveal the possible underlying mechanism. The adult mice were subjected to endovascular perforation SAH model or sham operation. Mice were randomized to sham group, SAH group, or SAH+NBP group. The EBI (short-term study) was studied at 48 h post-SAH and delayed neurological dysfunction (long-term study) at 21 days post-SAH. The results suggested that NBP evidently alleviated the EBI in mice at 48 h post-SAH, as shown by elevating neurological score, reducing brain edema, blood-brain barrier disruption, neuronal loss, and astrocyte aggregation, as well as ameliorating cerebral vasospasm. Moreover, NBP was able to improve long-term neurobehavioral functions and decrease neuronal apoptosis at 21 days after SAH. Significantly, NBP treatment also inhibited the expressions of NLRP3, ASC, caspase-1, cleaved-caspase-1, IL-1β, IL-18, GSDMD and GSDMD-N in both EBI and delayed neurological dysfunction induced by SAH. Our findings suggested that NBP treatment exerts a profound neuroprotective effect against early brain injury and delayed neurological dysfunction induced by SAH, at least partially through regulating NLRP3 inflammasome signaling pathway and its related inflammation and pyroptosis.

Neurobehavioral Impairments Predict Specific Cerebral Damage in Rat Model of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a severe form of stroke that can cause unpredictable and diffuse cerebral damage, which is difficult to detect until it becomes irreversible. Therefore, there is a need for a reliable method to identify dysfunctional regions and initiate treatment before permanent damage occurs. Neurobehavioral assessments have been suggested as a possible tool to detect and approximately localize dysfunctional cerebral regions. In this study, we hypothesized that a neurobehavioral assessment battery could be a sensitive and specific method for detecting damage in discrete cerebral regions following SAH. To test this hypothesis, a behavioral battery was employed at multiple time points after SAH induced via an endovascular perforation, and brain damage was confirmed via postmortem histopathological analysis. Our results demonstrate that impairment of sensorimotor function accurately predict damage in the cerebral cortex (AUC 0.905; sensitivity 81.8%; specificity 90.9%) and striatum (AUC 0.913; sensitivity 90.1%; specificity 100%), while impaired novel object recognition is a more accurate indicator of damage to the hippocampus (AUC 0.902; sensitivity 74.1%; specificity 83.3%) than impaired reference memory (AUC 0.746; sensitivity 72.2%; specificity 58.0%). Tests for anxiety-like and depression-like behaviors predict damage to the amygdala (AUC 0.900; sensitivity 77.0%; specificity 81.7%) and thalamus (AUC 0.963; sensitivity 86.3%; specificity 87.8%), respectively. This study suggests that recurring behavioral testing can accurately predict damage in specific brain regions, which could be developed into a clinical battery for early detection of SAH damage in humans, potentially improving early treatment and outcomes.

The urotensin II receptor triggers an early meningeal response and a delayed macrophage-dependent vasospasm after subarachnoid hemorrhage in male mice

Subarachnoid hemorrhage (SAH) can be associated with neurological deficits and has profound consequences for mortality and morbidity. Cerebral vasospasm (CVS) and delayed cerebral ischemia affect neurological outcomes in SAH patients, but their mechanisms are not fully understood, and effective treatments are limited. Here, we report that urotensin II receptor UT plays a pivotal role in both early events and delayed mechanisms following SAH in male mice. Few days post-SAH, UT expression is triggered by blood or hemoglobin in the leptomeningeal compartment. UT contributes to perimeningeal glia limitans astrocyte reactivity, microvascular alterations and neuroinflammation independent of CNS-associated macrophages (CAMs). Later, CAM-dependent vascular inflammation and subsequent CVS develop, leading to cognitive dysfunction. In an SAH model using humanized UTh+/h+ male mice, we show that post-SAH CVS and behavioral deficits, mediated by UT through Gq/PLC/Ca2+ signaling, are prevented by UT antagonists. These results highlight the potential of targeting UT pathways to reduce early meningeal response and delayed cerebral ischemia in SAH patients.

Review of current treatment modalities and clinical outcome of giant saccular aneurysms of the basilar apex

Introduction

Giant aneurysms of the basilar apex represent formidable challenges as the high rupture rate of untreated lesions must be balanced against the technical complexity and potential morbidity of intervention.

Research question

Review of treatment modalities and outcomes of patients harboring giant (>2.5 cm) basilar apex saccular aneurysms, in an effort to refine treatment decision-making.

Material and methods

A systematic literature review through the PubMed and Scopus databases was performed according to the PRISMA guidelines to identify cases of giant basilar apex saccular aneurysms treated either microsurgically or endovascularly. Patients' demographics, aneurysm size, preoperative and postoperative neurologic status, angiographic and clinical outcomes as well as follow-up information were obtained.

Results

Data from 32 studies fulfilling the inclusion criteria, including 49 patients (32 treated surgically and 17 endovascularly) was obtained. Mean patient age at presentation was 51.69 years, with a male-to-female ratio of 1:2. Mean maximum aneurysm diameter was 30.57 mm. A favorable outcome (mRS 0-2) was reported on 70.6% of endovascular and 56.3% of open surgical cases. Complete aneurysm occlusion was achieved in 55.6% of the open and 23.5% of the endovascular cases. Death rate was 33% for endovascular and 15.6% for open cases; the higher mortality of endovascular treatment is mainly attributed to the mass effect from continued brainstem compression after treatment.

Discussion and conclusion

Higher rates of complete occlusion but higher morbidity are associated with microsurgery compared to endovascular modalities. Severe, clinically apparent brainstem mass effect may require decompression associated with microsurgery, when technically feasible.

Risk factors and predictive indicators of rupture in cerebral aneurysms

Cerebral aneurysms are abnormal dilations of blood vessels in the brain that have the potential to rupture, leading to subarachnoid hemorrhage and other serious complications. Early detection and prediction of aneurysm rupture are crucial for effective management and prevention of rupture-related morbidities and mortalities. This review aims to summarize the current knowledge on risk factors and predictive indicators of rupture in cerebral aneurysms. Morphological characteristics such as aneurysm size, shape, and location, as well as hemodynamic factors including blood flow patterns and wall shear stress, have been identified as important factors influencing aneurysm stability and rupture risk. In addition to these traditional factors, emerging evidence suggests that biological and genetic factors, such as inflammation, extracellular matrix remodeling, and genetic polymorphisms, may also play significant roles in aneurysm rupture. Furthermore, advancements in computational fluid dynamics and machine learning algorithms have enabled the development of novel predictive models for rupture risk assessment. However, challenges remain in accurately predicting aneurysm rupture, and further research is needed to validate these predictors and integrate them into clinical practice. By elucidating and identifying the various risk factors and predictive indicators associated with aneurysm rupture, we can enhance personalized risk assessment and optimize treatment strategies for patients with cerebral aneurysms.

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.

Gender-specific prognosis models reveal differences in subarachnoid hemorrhage patients between sexes

BACKGROUND

Subarachnoid hemorrhage (SAH) represents a severe stroke subtype. Our study aims to develop gender-specific prognostic prediction models derived from distinct prognostic factors observed among different-gender patients.

METHODS

Inclusion comprised SAH-diagnosed patients from January 2014 to March 2016 in our institution. Collected data encompassed patients' demographics, admission severity, treatments, imaging findings, and complications. Three-month post-discharge prognoses were obtained via follow-ups. Analyses assessed gender-based differences in patient information. Key factors underwent subgroup analysis, followed by univariate and multivariate analyses to identify gender-specific prognostic factors and establish/validate gender-specific prognostic models.

RESULTS

A total of 929 patients, with a median age of 57 (16) years, were analyzed; 372 (40%) were male, and 557 (60%) were female. Differences in age, smoking history, hypertension, aneurysm presence, and treatment interventions existed between genders (p < 0.01), yet no disparity in prognosis was noted. Subgroup analysis explored hypertension history, aneurysm presence, and treatment impact, revealing gender-specific variations in these factors' influence on the disease. Screening identified independent prognostic factors: age, SEBES score, admission GCS score, and complications for males; and age, admission GCS score, intraventricular hemorrhage, treatment interventions, symptomatic vasospasm, hydrocephalus, delayed cerebral ischemia, and seizures for females. Evaluation and validation of gender-specific models yielded an AUC of 0.916 (95% CI: 0.878-0.954) for males and 0.914 (95% CI: 0.885-0.944) for females in the ROC curve. Gender-specific prognostic models didn't significantly differ from the overall population-based model (model 3) but exhibited robust discriminative ability and clinical utility.

CONCLUSION

Variations in baseline and treatment-related factors among genders contribute partly to gender-based prognosis differences. Independent prognostic factors vary by gender. Gender-specific prognostic models exhibit favorable prognostic performance.

Perianeurysmal vasogenic oedema (PAVO): A single centre 10-year retrospective review

INTRODUCTION

Perianeurysmal Vasogenic Oedema (PAVO) is a rare but important complication of endovascular treatment of intracranial aneurysms. Many potential risk factors have been identified including age, aneurysm size, aneurysm location, immunological profile, type of coil used, diabetes, hypertension, and smoking. PAVO can cause persistent post-procedural symptoms, subsequently increasing post-embolization morbidity.

METHODS

A 10-year retrospective review was conducted between 2011 and 2021 at Royal Preston Hospital, Preston, UK.

RESULTS

We identified 8 patients that fit our inclusion criteria. This included 6 (75%) females and 2 (25%) males. The mean age was 64. All patients had anterior circulation aneurysms with the middle cerebral artery (MCA) being the most common site. The mean aneurysm size was 12 mm. Our patients were managed with a range of endovascular techniques. One patient had pre-treatment PAVO while 7 patients had post-embolization PAVO. Five patients were symptomatic, and 3 cases were asymptomatic with only radiological evidence of PAVO. Five patients were managed with varying courses of dexamethasone. PAVO resolution was achieved in 4 cases. The oedema significantly improved in 3 cases, but transiently progressed in 1 case.

CONCLUSIONS

PAVO is a rare but important complication of endovascular management of intracranial aneurysms. We have shown that patients can be effectively managed with steroids with resultant oedema regression and symptomatic improvement. Many risk factors have been associated with PAVO, but further research is needed to better understand their role in PAVO development and help develop other therapeutic options.

Protein kinase C-inhibition reduces critical weight loss and improves functional outcome after experimental subarachnoid haemorrhage

OBJECTIVES

Subarachnoid haemorrhage (SAH) carries a high burden of morbidity and mortality. One in three patients develop vasospasm, which is associated with Delayed Cerebral Ischemia. The pathophysiology includes vasoconstrictor receptor upregulation in cerebral arteries. The protein kinase C - inhibitor RO-31-7549 reduces the expression of several vasoconstrictor receptors and normalizes cerebral blood flow in experimental SAH but functional and behavioural effects are unknown. This study was undertaken to analyse functional outcomes up to 14 days after experimental SAH.

MATERIALS AND METHODS

54 male rats were randomised to experimental SAH or sham, using the pre-chiasmatic, single injection model, and subsequent treatment or vehicle. 42 remained for final analysis. The animals were euthanized on day 14 or when reaching a humane endpoint. The primary endpoint was overall survival, defined as either spontaneous mortality or when reaching a predefined humane endpoint. The secondary outcomes were differences in the rotating pole test, weight, open field test, novel object recognition and qPCR of selected inflammatory markers.

RESULTS

In the vehicle group 6/15 rats reached the humane endpoint of >20 % weight loss compared to 1/14 in the treatment group. This resulted in a significant reduced risk of early euthanasia due to >20 % weight loss of HR 0.15 (0.03-0.66, p = 0.04). Furthermore, the treatment group did significantly better on the rotating pole test, RR 0.64 (0.47-0.91, p = 0.02).

CONCLUSION

RO-31-7549 improved outcomes in terms >20 % weight loss and rotating pole performance after experimental SAH and could be investigated.

Haemorrhagic stroke and brain vascular malformations in women: risk factors and clinical features

Haemorrhagic stroke is a severe condition with poor prognosis. Biological sex influences the risk factors, presentations, treatment, and patient outcomes of intracerebral haemorrhage, aneurysmal subarachnoid haemorrhage, and vascular malformations. Women are usually older at onset of intracerebral haemorrhage compared with men but have an increased risk of aneurysmal subarachnoid haemorrhage as they age. Female-specific factors such as pregnancy, eclampsia or pre-eclampsia, postmenopausal status, and hormone therapy influence a woman's long-term risk of haemorrhagic stroke. The presence of intracranial aneurysms, arteriovenous malformations, or cavernous malformations poses unique clinical dilemmas during pregnancy and delivery. In the absence of evidence-based guidelines for managing the low yet uncertain risk of haemorrhagic stroke during pregnancy and delivery in women with vascular malformations, multidisciplinary teams should carefully assess the risks and benefits of delivery methods for these patients. Health-care providers should recognise and address the challenges that women might have to confront when recovering from haemorrhagic stroke.

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.

Development of a predictive nomogram for 28-day mortality risk in non-traumatic or post-traumatic subarachnoid hemorrhage patients

OBJECTIVE

Subarachnoid hemorrhage (SAH) is associated with high rates of mortality and permanent disability. At present, there are few definite clinical tools to predict prognosis in SAH patients. The current study aims to develop and assess a predictive nomogram model for estimating the 28-day mortality risk in both non-traumatic or post-traumatic SAH patients.

METHODS

The MIMIC-III database was searched to select patients with SAH based on ICD-9 codes. Patients were separated into non-traumatic and post-traumatic SAH groups. Using LASSO regression analysis, we identified independent risk factors associated with 28-day mortality and incorporated them into nomogram models. The performance of each nomogram was assessed by calculating various metrics, including the area under the curve (AUC), net reclassification improvement (NRI), integrated discrimination improvement (IDI), and decision curve analysis (DCA).

RESULTS

The study included 999 patients with SAH, with 631 in the non-traumatic group and 368 in the post-traumatic group. Logistic regression analysis revealed critical independent risk factors for 28-day mortality in non-traumatic SAH patients, including gender, age, glucose, platelet, sodium, BUN, WBC, PTT, urine output, SpO2, and heart rate and age, glucose, PTT, urine output, and body temperature for post-traumatic SAH patients. The prognostic nomograms outperformed the commonly used SAPSII and APSIII systems, as evidenced by superior AUC, NRI, IDI, and DCA results.

CONCLUSION

The study identified independent risk factors associated with the 28-day mortality risk and developed predictive nomogram models for both non-traumatic and post-traumatic SAH patients. The nomogram holds promise in guiding prognosis improvement strategies for patients with SAH.

Subarachnoid hemorrhage-associated brain injury and neurobehavioral deficits are reversed with synthetic adropin treatment through sustained Ser1179 phosphorylation of endothelial nitric oxide synthase

Background

Subarachnoid hemorrhage (SAH) is a life-threatening vascular condition without satisfactory treatment options. The secreted peptide adropin is highly expressed in the human brain and has neuroprotective effects in brain injury models, including actions involving the cerebrovasculature. Here, we report an endothelial nitric oxide synthase (eNOS)-dependent effect of synthetic adropin treatment that reverses the deleterious effects of SAH.

Methods

We tested the molecular, cellular, and physiological responses of cultured brain microvascular endothelial cells and two mouse models of SAH to treatment using synthetic adropin peptide or vehicle.

Results

SAH decreases adropin expression in cultured brain microvascular endothelial cells and in murine brain tissue. In two validated mouse SAH models, synthetic adropin reduced cerebral edema, preserved tight junction protein expression, and abolished microthrombosis at 1 day post-SAH. Adropin treatment also prevented delayed cerebral vasospasm, decreased neuronal apoptosis, and reduced sensorimotor deficits at seven days post-SAH. Delaying initial treatment of adropin until 24 h post-SAH preserved the beneficial effect of adropin in preventing vasospasm and sensorimotor deficits. Mechanistically, adropin treatment increased eNOS phosphorylation (Ser1179) at 1 & 7 days post-SAH. Treating eNOS-/- mice with adropin failed to prevent vasospasm or behavioral deficits, indicating a requirement of eNOS signaling.

Conclusions

Adropin is an effective treatment for SAH, reducing cerebrovascular injury in both the acute (1 day) and delayed (7 days) phases. These findings establish the potential of adropin or adropin mimetics to improve outcomes following subarachnoid hemorrhage.

Association of Gut Microbiome with Early Brain Injury After Subarachnoid Hemorrhage: an Experimental Study

The occurrence of early brain injury (EBI) following subarachnoid hemorrhage (SAH) is crucial in the prognosis of SAH; however, no effective treatment for EBI has been developed. Gut microbiome (GM) composition influences the outcome of various diseases, including ischemic stroke. Here, we evaluated whether prior GM alteration could prevent EBI following SAH. We altered the GM of 7-week-old male rats by administering antibiotic-containing water for 2 weeks and performing fecal microbiome transplantation after antibiotic induction. Composition of the GM was profiled using 16S rRNA. We induced SAH by injecting blood in the subarachnoid space of control rats and rats with altered GM. We evaluated EBI indicators such as neurological score, brain water content, Evans blue extravasation, and neuronal injury. Additionally, we studied inflammatory cells using immunohistochemistry, immunocytochemistry, quantitative PCR, and flow cytometry. EBI was significantly averted by alterations in GM using antibiotics. The altered GM significantly prevented neutrophil infiltration into the brain among inflammatory cells, and this anti-inflammatory effect was observed immediately following SAH onset. The altered GM also prevented neutrophil extracellular trap formation in the brain and blood, indicating the systemic protective effect. The cause of the protective effect was attributed to a significant decrease in aged neutrophils (CXCR4high CD62Llow) by the altered GM. These protective effects against EBI disappeared when the altered GM was recolonized with normal flora. Our findings demonstrated that EBI following SAH is associated with GM, which regulated neutrophil infiltration.

Correlation between the rate of morphological changes and rupture of intracranial aneurysms during one cardiac cycle analyzed by 4D-CTA

Objective

This study aimed to analyze the relationship between the rate of morphological changes and intracranial aneurysm rupture during the cardiac cycle.

Methods

Eighty-four patients with intracranial aneurysms were retrospectively analyzed and divided into the rupture (42 cases) and unruptured (42 cases) groups. Four-dimensional computed tomography angiography (4D-CTA) was performed to collect quantitative parameters of aneurysm morphology and calculate the morphological change rate. The potential factors associated with aneurysm rupture were determined by comparing the general clinical data and rate of change in the location and morphology of the aneurysm between the two groups.

Results

Each morphological change rate in the rupture group was generally higher than that of the unruptured group. The rate of dome height change and aneurysm volume change were independent factors associated with aneurysm rupture. ROC curve analysis revealed that the diagnostic accuracy of the aneurysm volume change rate was higher. When the volume change rate was 12.33%, the sensitivity and specificity of rupture were 90.5 and 55.8%, respectively.

Conclusion

The rate of change in dome height and volume of intracranial aneurysms during one cardiac cycle were independent factors associated with aneurysm rupture.

Ravoxertinib Improves Long-Term Neurologic Deficits after Experimental Subarachnoid Hemorrhage through Early Inhibition of Erk1/2

Extracellular signal-regulated kinase 1 and 2 (Erk1/2) signaling has been shown to be involved in brain injury after subarachnoid hemorrhage (SAH). A first-in-human phase I study reported that ravoxertinib hydrochloride (RAH), a novel Erk1/2 inhibitor, has an acceptable safety profile and pharmacodynamic effects. Here, we showed that the level of Erk1/2 phosphorylation (p-Erk1/2) was significantly increased in the cerebrospinal fluid (CSF) of aneurysmal subarachnoid hemorrhage (aSAH) patients who developed poor outcomes. In a rat SAH model that was produced by the intracranial endovascular perforation method, western blot observed that the level of p-Erk1/2 was also increased in the CSF and basal cortex, showing a similar trend with aSAH patients. Immunofluorescence and western blot indicated that RAH treatment (i.c.v injection, 30 min post-SAH) attenuates the SAH-induced increase of p-Erk1/2 at 24 h in rats. RAH treatment can improve experimental SAH-induced long-term sensorimotor and spatial learning deficits that are evaluated by the Morris water maze, rotarod test, foot-fault test, and forelimb placing test. Moreover, RAH treatment attenuates neurobehavioral deficits, the blood-brain barrier damage, and cerebral edema at 72 h after SAH in rats. Furthermore, RAH treatment decreases the SAH-elevated apoptosis-related factor active caspase-3 and the necroptosis-related factor RIPK1 expression at 72 h in rats. Immunofluorescence analysis showed that RAH attenuated neuronal apoptosis but not neuronal necroptosis in the basal cortex at 72 h after SAH in rats. Altogether, our results suggest that RAH improves long-term neurologic deficits through early inhibition of Erk1/2 in experimental SAH.

Predictive factors for pre-intervention rebleeding in aneurysmal subarachnoid haemorrhage: a systematic review and meta-analysis

Rebleeding before intervention is a devastating complication of aneurysmal subarachnoid haemorrhage (aSAH). It often occurs early and is associated with poor outcomes. We present a systematic review and meta-analysis to identify potential predictors of rebleeding in aSAH. A database search identified studies detailing the occurrence of pre-intervention rebleeding in aSAH, and 809 studies were screened. The association between rebleeding and a variety of demographic, clinical, and radiological factors was examined using random effects meta-analyses. Fifty-six studies totalling 33,268 patients were included. Rebleeding occurred in 3,223/33,268 patients (11.1%, 95%CI 9.4-13), with risk decreasing by approximately 0.2% per year since 1981. Systolic blood pressure (SBP) during admission was higher in patients who rebled compared with those who did not (MD 7.4 mmHg, 95%CI 2.2 - 12.7), with increased risk in cohorts with SBP > 160 mmHg (RR 2.12, 95%CI 1.35-3.34), but not SBP > 140 mmHg. WFNS Grades IV-V (RR 2.05, 95%CI 1.13-3.74) and Hunt-Hess grades III-V (RR 2.12, 95%CI 1.38-3.28) were strongly associated with rebleeding. Fisher grades IV (RR 2.24, 95%CI 1.45-3.49) and III-IV (RR 2.05, 95%CI 1.17-3.6) were also associated with an increased risk. Awareness of potential risk factors for rebleeding is important when assessing patients with aSAH to ensure timely management in high-risk cases. Increased SBP during admission, especially > 160 mmHg, poorer clinical grades, and higher radiological grades are associated with an increased risk. These results may also aid in designing future studies assessing interventions aimed at reducing the risk of rebleeding.

The MEK Inhibitor Trametinib Improves Outcomes following Subarachnoid Haemorrhage in Female Rats

Aneurysmal subarachnoid haemorrhage (SAH) is a haemorrhagic stroke that causes approximately 5% of all stroke incidents. We have been working on a treatment strategy that targets changes in cerebrovascular contractile receptors, by blocking the MEK/ERK1/2 signalling pathway. Recently, a positive effect of trametinib was found in male rats, but investigations of both sexes in pre-clinical studies are an important necessity. In the current study, a SAH was induced in female rats, by autologous blood-injection into the pre-chiasmatic cistern. This produces a dramatic, transient increase in intracranial pressure (ICP) and an acute and prolonged decrease in cerebral blood flow. Rats were then treated with either vehicle or three doses of 0.5 mg/kg trametinib (specific MEK/ERK1/2 inhibitor) intraperitoneally at 3, 9, and 24 h after the SAH. The outcome was assessed by a panel of tests, including intracranial pressure (ICP), sensorimotor tests, a neurological outcome score, and myography. We observed a significant difference in arterial contractility and a reduction in subacute increases in ICP when the rats were treated with trametinib. The sensory motor and neurological outcomes in trametinib-treated rats were significantly improved, suggesting that the improved outcome in females is similar to that of males treated with trametinib.

Sex and gender differences in dementia

The dementia landscape has undergone a striking paradigm shift. The advances in understanding of neurodegeneration and proteinopathies has changed our approach to patients with cognitive impairment. Firstly, it has recently been shown that the various proteinopathies that are the cause of the dementia begin to build up long before the appearance of any obvious symptoms. This has cemented the idea that there is an urgency in diagnosis as it occurs very late in the pathophysiology of these diseases. Secondly, that accurate diagnosis is required to deliver targeted therapies, that is precision medicine. With this latter point, the realization that various factors of a person need to be considered as they may impact the presentation and progression of disease has risen to the forefront. Two of these factors aside from race and age are biological sex and gender (social construct), as both can have tremendous impact on manifestation of disease. This chapter will cover what is known and remains to be known on the interaction of sex and gender with some of the major causes of dementia.

Sex differences in neurovascular disorders

Neurovascular disorders is a heterogenous group of diseases, including one of the most time critical disorders in emergency medicine; stroke. Sex differences are extensively described in neurovascular disorders, ranging from differences in symptom presentation, risk factors, treatment and outcomes. For example, women with stroke, more often present with generalized weakness, reduced consciousness and headache than men. Furthermore, there are differences in risk factors, outcomes and in the effect of secondary prevention. Women have a higher risk of cerebral venous thrombosis and developing cerebral aneurysms. In general, women have been underrepresented in trials on neurovascular disorders. This chapter provides an extensive overview of sex differences in stroke in general and in the differences specially seen in ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage and in cerebral venous thrombosis.

Comparison of Sex Differences in Outcomes of Patients With Aneurysmal Subarachnoid Hemorrhage: A Single-Center Retrospective Study

Background

Sex differences in the outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH) remain controversial. The aim of this study was to evaluate sex differences in the outcomes of patients with aSAH.

Method

This study retrospectively analyzed the clinical data of consecutive patients with aSAH, admitted to the Department of Neurosurgery, Wuhan University Zhongnan Hospital, from May 1, 2020 to December 31, 2020. The modified Rankin Scale (mRS) score was used to evaluate the prognosis of patients at discharge. Outcome indicators included cerebral ischemia, hydrocephalus, and mRS ≥ 2 at discharge.

Results

The majority (65%) of the 287 patients with aSAH included in the study were females. Patients were divided into female (n = 184) and male (n = 99) groups; the female patients were significantly older than the male patients (61.3 ± 8.5 years vs. 60.0 ± 8.5 years, p = 0.032). The incidence of comorbidities (hypertension, diabetes, and heart disease) was higher in the female group than in the male group, but the difference was not statistically significant. Although more female patients than male patients underwent endovascular treatment, there was no statistical difference in the treatment approach between the two groups. Comparison of post-operative complications and mRS scores at discharge revealed that the rate of cerebral ischemia and mRS ≥ 2 at discharge were significantly higher among female patients than among male patients. Moreover, this difference persisted after propensity adjustment for age and treatment approach. Analysis of risk factors for poor prognosis at discharge in both pre- and post-adjustment patients revealed cerebral ischemia and high mFisher score (mFisher = 3/4) to be independent risk factors.

Conclusion

Female patients with aSAH have a worse prognosis than male patients, and this difference may be because women are more susceptible to cerebral ischemia.

The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments

The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.

Patterns and outcomes of neurosurgery in England over a five-year period: A national retrospective cohort study

BACKGROUND

Neurosurgical practice has seen major changes over several decades. There are no recent evaluations of national neurosurgical practice. The aim of this observational study was to describe neurosurgical practice in England and to use outcomes to assess and benchmark the quality of care in neurosurgery.

MATERIAL AND METHODS

This national retrospective cohort study analysed Hospital Episode Statistics (HES) data from April 2013 to March 2018 for all adult admissions with a specialty code for neurosurgery. The epidemiology of patients and RCS Charlson comorbidities were derived and procedure incidence rates per 100,000 person-years calculated. Post-operative outcomes for elective and non-elective patients included: median length of stay, the proportion of patients requiring additional inpatient neurosurgical procedures, the proportion of patients discharged to their usual address, and in-hospital mortality rates.

RESULTS

During the 5-year study period, there were 371,418 admissions to neurosurgery. The proportion of admissions involving a neurosurgical procedure was 77.3% (n = 287,077). Of these, 45% were for cranial surgery and 37% for spinal. Overall, 68.3% were elective procedures. The incidence rates of most procedures were low (<20 per 100,000 person-years). Following elective neurosurgical procedures, in-hospital mortality rates for cranial and spinal surgery were 0.5% (95% CI, 0.5-0.6) and 0.1% (95% CI, 0.04-0.1), respectively. After non-elective neurosurgery, mortality rates were 7.4% (95% CI, 7.2-7.6) and 1.3% (95% CI, 1.2-1.5) for cranial and spinal surgery, respectively. Approximately 1 in 4 patients had additional procedures following non-elective cranial surgery (24%; 95% CI, 23.6-24.3). Outcomes were highly variable across different subspecialty areas.

CONCLUSIONS

The incidence rates of neurosurgical procedures are low within England, and neurosurgical units have a high volume of non-surgical admissions. In-hospital mortality rates after elective neurosurgery are low but there may be opportunities for quality improvement programmes to improve outcomes for non-elective surgery as well as ensuring equitable access to treatment.

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.

DCI after Aneurysmal Subarachnoid Hemorrhage Is Related to the Expression of MFG-E8

Objective

To explore the predictive value of milk fat globule epidermal growth factor 8 (MFG-E8) in the occurrence of delayed cerebral ischemia (DCI) after an aneurysmal subarachnoid hemorrhage (aSAH).

Methods

We recruited 32 patients with aSAH as the case group and 24 patients with unruptured aneurysms as the control group. Serum MFG-E8 levels were measured by western blot and enzyme-linked immunosorbent assay. We analyzed the relationship between MFG-E8 levels and the risk of DCI.

Results

The levels of serum MFG-E8 in the case group (mean = 11160.9 pg/mL) were significantly higher than those in the control group (mean = 3081.0 pg/mL, p < 0.001). MFG-E8 levels highly correlated with the World Federation of Neurosurgical Societies (WFNS) and modified Fisher scores (r = -0.691 and - 0.767, respectively, p < 0.001). In addition, MFG-E8 levels in patients with DCI (5882.7 ± 3162.4 pg/mL) were notably higher than those in patients without DCI (15818.2 ± 3771.6 pg/mL, p < 0.001). A receiver operating characteristic curve showed that the occurrence of DCI could effectively be predicted by MFG-E8 (area under the curve = 0.976, 95%CI = 0.850-1.000). Kaplan-Meier survival analysis showed a remarkable decrease in the incidence of DCI in case group individuals with high levels of MFG-E8 (≥11160.9 pg/mL, p < 0.001).

Conclusion

MFG-E8 may be a useful predictive marker for DCI after an aSAH and could be a promising surrogate end point.

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.

LncRNA ANRIL Facilitates Vascular Smooth Muscle Cell Proliferation and Suppresses Apoptosis via Modulation of miR-7/FGF2 Pathway in Intracranial Aneurysms

BACKGROUND

Proliferation and apoptosis of vascular smooth muscle cells (VSMCs) are linked to intracranial aneurysm (IA) formation and progression. Long antisense noncoding RNA in the INK4 locus (ANRIL) has been reported to regulate VSMC functions in several cardiovascular diseases. However, little is known about how ANRIL influences VSMC proliferation and apoptosis during IA pathogenesis.

METHODS

The expression level of ANRIL in the plasma and arterial wall tissues of patients with IA was detected by real-time quantitative polymerase chain reaction. The functional role of ANRIL in the regulation of VSMC proliferation and apoptosis and its downstream regulatory mechanism were determined using Cell Counting Kit 8, immunofluorescence, terminal-deoxynucleotidyl transferase-mediated UTP nick end labeling, western blotting, luciferase reporter assay, and RNA immunoprecipitation assay.

RESULTS

ANRIL was downregulated in the plasma and arterial wall tissues of patients with IA, when compared with control groups. Overexpression of ANRIL significantly promoted VSMC proliferation and blocked cell apoptosis. Mechanistic studies demonstrated that ANRIL directly bound to microRNA-7 (miR-7) and that overexpression of miR-7 overturned the increased cell proliferation and decreased cell apoptosis, which was induced by ANRIL restoration. Besides, further study showed that ANRIL positively regulated fibroblast growth factor 2 (FGF2) expression via targeting miR-7.

CONCLUSIONS

These results suggested that ANRIL affects VSMC proliferation and apoptosis via regulation of the miR-7/FGF2 pathway in IA, which provided a potential novel strategy for the treatment of IA.

NLRP3 inhibition attenuates early brain injury and delayed cerebral vasospasm after subarachnoid hemorrhage

BACKGROUND

The NLRP3 inflammasome is a critical mediator of several vascular diseases through positive regulation of proinflammatory pathways. In this study, we defined the role of NLRP3 in both the acute and delayed phases following subarachnoid hemorrhage (SAH). SAH is associated with devastating early brain injury (EBI) in the acute phase, and those that survive remain at risk for developing delayed cerebral ischemia (DCI) due to cerebral vasospasm. Current therapies are not effective in preventing the morbidity and mortality associated with EBI and DCI. NLRP3 activation is known to drive IL-1β production and stimulate microglia reactivity, both hallmarks of SAH pathology; thus, we hypothesized that inhibition of NLRP3 could alleviate SAH-induced vascular dysfunction and functional deficits.

METHODS

We studied NLRP3 in an anterior circulation autologous blood injection model of SAH in mice. Mice were randomized to either sham surgery + vehicle, SAH + vehicle, or SAH + MCC950 (a selective NLRP3 inhibitor). The acute phase was studied at 1 day post-SAH and delayed phase at 5 days post-SAH.

RESULTS

NLRP3 inhibition improved outcomes at both 1 and 5 days post-SAH. In the acute (1 day post-SAH) phase, NLRP3 inhibition attenuated cerebral edema, tight junction disruption, microthrombosis, and microglial reactive morphology shift. Further, we observed a decrease in apoptosis of neurons in mice treated with MCC950. NLRP3 inhibition also prevented middle cerebral artery vasospasm in the delayed (5 days post-SAH) phase and blunted SAH-induced sensorimotor deficits.

CONCLUSIONS

We demonstrate a novel association between NLRP3-mediated neuroinflammation and cerebrovascular dysfunction in both the early and delayed phases after SAH. MCC950 and other NLRP3 inhibitors could be promising tools in the development of therapeutics for EBI and DCI.

Microsurgical Clipping of Carotid-Ophthalmic Tandem Aneurysms: Case Report and Surgical Nuances

Tandem intracranial aneurysms (TandIAs) are rare but inherently complex, and special technical considerations are required for their surgical management. The present case highlights the key surgical aspects of two carotid-ophthalmic TandIAs incidentally found in a 60-year-old female. Both the aneurysms were superiorly projecting, regular in size, and involved the left ophthalmic segment of the internal carotid artery (ICA). The minimum distance between the necks was 3 mm. The patient underwent microsurgery because of the reported major complications rate of the endovascular treatment in the case of a very short minimum distance between the TandIAs. After cervical ICA exposure, both the aneurysms were excluded through a pterional approach. Intradural anterior clinoidectomy and unroofing of the optic canal allowed the mobilization of the left optic nerve. The more distal aneurysm was clipped before the opening of the distal dural ring of the ICA. The proximal aneurysm was clipped with two straight clips stacked perpendicular to the ICA. A small remnant was intentionally left to avoid the stenosis of the ophthalmic artery. Postoperative angiography showed the exclusion of both the aneurysms with a small dog-ear of the more proximal one. The patient was discharged neurologically intact and, after one year, the remnant remained stable. Microsurgical clipping is a definitive and durable treatment for carotid-ophthalmic TandIAs. In the case of a very short minimum distance between the aneurysms, the distal one should be clipped first to make the anterior clinoidectomy, opening of the distal dural ring of the ICA, and clipping of the more proximal aneurysm easier.

Subacute phase of subarachnoid haemorrhage in female rats: Increased intracranial pressure, vascular changes and impaired sensorimotor function

OBJECTIVE

Early brain injury (EBI) and delayed cerebral ischemia (DCI) after subarachnoid haemorrhage (SAH) has devastating consequences but therapeutic options and the underlying pathogenesis remain poorly understood despite extensive preclinical and clinical research. One of the drawbacks of most preclinical studies to date is that the mechanisms behind DCI after SAH are studied only in male animals. In this study we therefore established a female rat model of SAH in order to determine subacute pathophysiological changes that may contribute to DCI in females.

METHODS

Experimental SAH was induced in female rats by intracisternal injection of 300 μL of autologous blood. Sham operation served as a control. Neurological deficits and intracranial pressure measurements were evaluated at both 1 and 2 days after surgery. Additionally, changes in cerebral vascular contractility were evaluated 2 days after surgery using wire myography.

RESULTS

SAH in female rats resulted in sensorimotor deficits and decreased general wellbeing on both day 1 and day 2 after SAH. Intracranial pressure uniformly increased in all rats subjected to SAH on day 1. On day 2 the intracranial pressure had increased further, decreased slightly or remained at the level seen on day 1. Furthermore, female rats subjected to SAH developed cortical brain edema. Cerebral arteries, isolated 2 days after SAH, exhibited increased vascular contractions to endothelin-1 and 5-carboxamidotryptamine.

CONCLUSION

In the subacute phase after SAH in female rats, we observed increased intracranial pressure, decreased wellbeing, sensorimotor deficits, increased vascular contractility and cortical brain edema. Collectively, these pathophysiological changes may contribute to DCI after SAH in females. Previous studies reported similar pathophysiological changes for male rats in the subacute phase after SAH. Thus, prevention of these gender-independent mechanisms may provide the basis for a universal treatment strategy for DCI after SAH. Nevertheless, preclinical studies of potential therapies should employ both male and female SAH models.

Incidental Unruptured Intracranial Aneurysms Do Not Impact Outcome in Patients With Acute Cerebral Infarction

Background: This study was to examine the patients with acute cerebral infarction (ACI) treated at a single center over 9 years and who underwent Unruptured intracranial aneurysm (UIA) screening by three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA), and to explore the factors associated with outcomes.

Methods: The outcome was the modified Rankin scale (mRS) score at 90 days after stroke onset. The outcome was classified into a good outcome (mRS score of 0–2 points) and poor outcome (mRS score of 3–6 points).

Results: UIAs were found in 260 (6.5%) of 4,033 patients with ACI; 2,543 (63.1%) had a good outcome, and 1,490 (36.9%) had a poor outcome. There was no difference in outcomes between the two groups (P = 0.785). The multivariable analysis showed that age (OR = 1.009, 95%CI: 1.003–1.014, P = 0.003), diabetes (OR = 1.179, 95%CI: 1.035–1.342, P = 0.013), ischemic stroke history (OR = 1.451, 95%CI: 1.256–1.677, P < 0.001), and baseline NIHSS score (OR = 1.034, 95%CI: 1.018–1.050, P < 0.001) were independently associated with the 90-day outcomes in patients with ACI. The presence of incidental UIA was not associated with outcomes after ACI.

Conclusions: Age, diabetes, ischemic stroke history, and baseline NIHSS score were independently associated with the early outcomes of patients with ACI.

International Practice Variability in Treatment of Aneurysmal Subarachnoid Hemorrhage

Prior research suggests substantial between-center differences in functional outcome following aneurysmal subarachnoid hemorrhage (aSAH). One hypothesis is that these differences are due to practice variability. To characterize practice variability, we sent a survey to 230 centers, of which 145 (63%) responded. Survey respondents indicated that an estimated 65% of ruptured aneurysms were treated endovascularly. Sixty-five percent of aneurysms were treated within 24 h of symptom onset, 18% within 24–48 h, and eight percent within 48–72 h. Centers in the United States (US) and Europe (EU) treat aneurysms more often endovascularly (72% and 70% vs. 51%, respectively, US vs. other p < 0.001, and EU vs. other p < 0.01) and more often within 24 h (77% and 64% vs. 46%, respectively, US vs. other p < 0.001, EU vs. other p < 0.01) compared to other centers. Most centers aim for euvolemia (96%) by administrating intravenous fluids to 0 (53%) or +500 mL/day (41%) net fluid balance. Induced hypertension is more often used in US centers (100%) than in EU (87%, p < 0.05) and other centers (81%, p < 0.05), and endovascular therapies for cerebral vasospasm are used more often in US centers than in other centers (91% and 60%, respectively, p < 0.05). We observed significant practice variability in aSAH treatment worldwide. Future comparative effectiveness research studies are needed to investigate how practice variation leads to differences in functional outcome.

Rabbit Elastase Aneurysm: Imaging and Histology Correlates for Inflammation and Healing

OBJECTIVE

Aneurysmal subarachnoid hemorrhage remains a devastating event with poorly understood pathophysiology. Previous studies have suggested that aneurysm wall inflammation may play a part in the development and potential rupture of aneurysms. The rabbit elastase aneurysm model is a well-established model, which produces aneurysms closely mimicking human cerebral aneurysms in flow dynamics and histopathology. The primary aim of this study was to correlate inflammatory changes after aneurysm formation using sequential vessel wall imaging with histopathologic analysis. A secondary aim was to evaluate the potential effect of gender and anti-inflammatory treatment with aspirin on this inflammatory response.

METHODS

Twenty-seven New Zealand rabbits underwent surgery to create an aneurysm using elastase infusion at the right common carotid artery origin. Vessel wall imaging and histopathologic analysis was obtained at different time points after aneurysm creation. The rabbits were also randomized by gender and to treatment groups with or without aspirin.

RESULTS

Histopathologic analysis revealed 3 distinct phases after aneurysm formation. These phases were an initial inflammatory phase, followed by a regeneration phase, and finally a connective tissue deposition phase. Vessel wall imaging demonstrated 2 distinct imaging patterns. No appreciable differences were seen in histology or imaging when comparing gender or treatment with aspirin.

CONCLUSIONS

Inflammatory changes induced by the rabbit elastase aneurysm model can be correlated with histopathologic findings and observed on noninvasive vessel wall imaging. This may provide a method to study the inflammatory pathway as it pertains to aneurysmal development and subsequent rupture.

Characteristics of patients with ruptured very small intracranial aneurysm sized less than 3 mm

Objective

If the size of an intracranial aneurysm is below 3 mm, clinicians rarely treat them because of the low risk of rupture. But subarachnoid hemorrhage (SAH) due to the rupture of very small intracranial aneurysm (VSIA) (saccular aneurysm sized less than 3 mm) may lead to many critical neurological complications. So we analyzed the characteristics and differences between the ruptured VSIA group and the ruptured non-VSIA group.

Methods

421 saccular aneurysms from patients with SAH between January 2016 and December 2019 were included. Patient information including age, sex, and medical history and information about the aneurysm including location, size, aspect ratio, inflow angle, and height-width ratio were collected. And we compared the VSIA group with non-VSIA group about these characteristics

Results

12.1% (51/421) of the aneurysms were included in the VSIA group, while the non-VSIA group consisted of 87.9% of the aneurysms (370/421). The female predominance was significantly higher in the VSIA group than that in the non-VSIA group (p=0.011). No significant difference was observed in location, medical history, height-width ratio between the groups. The mean value of the inflow angle in the VSIA group was much lower than that in the non-VSIA group, but no statistically significant association between rupture risk and the inflow angle was observed. The average aspect ratio was significantly lower than that in the non-VSIA group.

Conclusions

Ruptured VSIA group has higher percentage of females and lower aspect ratio than ruptured non-VSIA group. Further studies regarding the characteristics of ruptured and unruptured VSIA patients is required for assistance in clinical decision related to treatment of VSIA group before the aneurysmal sac rupture.

Aneurysmal Subarachnoid Hemorrhage: the Last Decade

Aneurysmal subarachnoid hemorrhage (SAH) affects six to nine people per 100,000 per year, has a 35% mortality, and leaves many with lasting disabilities, often related to cognitive dysfunction. Clinical decision rules and more sensitive computed tomography (CT) have made the diagnosis of SAH easier, but physicians must maintain a high index of suspicion. The management of these patients is based on a limited number of randomized clinical trials (RCTs). Early repair of the ruptured aneurysm by endovascular coiling or neurosurgical clipping is essential, and coiling is superior to clipping in cases amenable to both treatments. Aneurysm repair prevents rebleeding, leaving the most important prognostic factors for outcome early brain injury from the hemorrhage, which is reflected in the neurologic condition of the patient, and delayed cerebral ischemia (DCI). Observational studies suggest outcomes are better when patients are managed in specialized neurologic intensive care units with inter- or multidisciplinary clinical groups. Medical management aims to minimize early brain injury, cerebral edema, hydrocephalus, increased intracranial pressure (ICP), and medical complications. Management then focuses on preventing, detecting, and treating DCI. Nimodipine is the only pharmacologic treatment that is approved for SAH in most countries, as no other intervention has demonstrated efficacy. In fact, much of SAH management is derived from studies in other patient populations. Therefore, further study of complications, including DCI and other medical complications, is needed to optimize outcomes for this fragile patient population.

The Role of Thrombin in Brain Injury After Hemorrhagic and Ischemic Stroke

Thrombin is increased in the brain after hemorrhagic and ischemic stroke primarily due to the prothrombin entry from blood either with a hemorrhage or following blood-brain barrier disruption. Increasing evidence indicates that thrombin and its receptors (protease-activated receptors (PARs)) play a major role in brain pathology following ischemic and hemorrhagic stroke (including intracerebral, intraventricular, and subarachnoid hemorrhage). Thrombin and PARs affect brain injury via multiple mechanisms that can be detrimental or protective. The cleavage of prothrombin into thrombin is the key step of hemostasis and thrombosis which takes place in every stroke and subsequent brain injury. The extravascular effects and direct cellular interactions of thrombin are mediated by PARs (PAR-1, PAR-3, and PAR-4) and their downstream signaling in multiple brain cell types. Such effects include inducing blood-brain-barrier disruption, brain edema, neuroinflammation, and neuronal death, although low thrombin concentrations can promote cell survival. Also, thrombin directly links the coagulation system to the immune system by activating interleukin-1α. Such effects of thrombin can result in both short-term brain injury and long-term functional deficits, making extravascular thrombin an understudied therapeutic target for stroke. This review examines the role of thrombin and PARs in brain injury following hemorrhagic and ischemic stroke and the potential treatment strategies which are complicated by their role in both hemostasis and brain.

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.

Intra- and inter-observer variability in intracranial aneurysm segmentation: comparison between CT angiography (semi-automated segmentation software stroke VCAR) and digital subtraction angiography (3D rotational angiography)

PURPOSE

To compare size and morphologic features of three-dimensional aneurysm models, obtained with a semi-automated segmentation software (Stroke VCAR, GE, USA) from cerebral CT angiography (CTA) data, to three-dimensional aneurysm models obtained with digital subtraction angiography (DSA, with 3D rotational angiography acquisition-3DRA), considered as the reference standard.

METHODS

In this retrospective study, we reviewed 132 patients, with a total number of 137 intracranial aneurysm, who underwent CTA and subsequent DSA examination, supplemented with 3DRA. We compared neck length, short axis and long axis measured on 3DRA model to the same variables measured on 3D-CTA model by two blinded readers and to the automatic software dimensions. Therefore, statistics analysis assessed intra-observer and inter-observer variability and differences between patients with or without subarachnoid hemorrhage (SAH).

RESULTS

There were no significant differences in short-axis and long-axis measurements between 3D angiographic and 3D-CTA models, while comparison of neck lengths revealed a statistically significant difference, which tended to be greater for smaller neck lengths (partial volume effect and "kissing vessels" artifact). There were significant differences between manual and automatic data measured for the same three variables, and the presence of SAH did not affect aneurysm 3D reconstruction. Inter-observer agreement resulted moderate for neck length and substantial for short axis and long axis.

CONCLUSION

The examined 3D-CTA segmentation system is a reproducible procedure for aneurysm morphologic characterization and, in particular, for assessment of aneurysm sac dimensions, but considerable carefulness is required in neck length interpretation.

Lifetime risks and health impacts of hemorrhagic and ischemic stroke in South Korea

This study is aimed toward estimating the lifetime risks, life expectancy, expected years of life lost (EYLL), and lifetime costs related to different subtypes of stroke in South Korea. We included 13,994 patients diagnosed with stroke (ICD-10, I60-I63) in the National Health Insurance Service-National Sample Cohort of Korea between 2006 and 2015. Lifetime risks were calculated using the cumulative incidence rate for patients aged 18–84. Lifetime survival data were obtained through the Kaplan–Meier method and extrapolated with a rolling-over extrapolation algorithm. The lifetime costs were estimated by multiplying the average monthly expenditures with the survival probabilities and adding the values over lifetime. The lifetime risks of stroke in Korea have been decreasing consistently over the last decade with the exception of subarachnoid hemorrhage in females, which appears to have slightly increased. The EYLL is higher in hemorrhagic stroke than in ischemic stroke (6–9.7 vs. 4.7). Expected lifetime costs reimbursed by the NHIS would amount to about $71,406 accompanied with $14,921 copayment from the patients for hemorrhagic stroke, and $50,551 and $11,666, respectively, for ischemic stroke. Further studies are warranted to combine survival with quality of life and functional disability to obtain a more detailed outcome assessment of the potential impact of the prevention of stroke.

Roles of Prokineticin 2 in Subarachnoid Hemorrhage-Induced Early Brain Injury via Regulation of Phenotype Polarization in Astrocytes

Previous studies have postulated that neuroinflammation can induce two different types of reactive astrocytes, A1 and A2. A1 astrocytes may be harmful, whereas A2 astrocytes may be protective. Specifically, prokineticin 2 (PK2) has been shown to regulate neuron-astrocyte signaling mechanism by promoting an alternative A2-protective phenotype in astrocytes. This study aimed to examine the role of PK2 in early brain injury (EBI) caused by subarachnoid hemorrhage (SAH). SAH-induced astrocytic activation was confirmed by Western blotting. We confirmed C3 and PTX3 as appropriate reactivity markers for discriminating A1 and A2 astrocytes, respectively. We also observed SAH-induced astrocytic activation in SAH patients. The increase of PK2 in neurons after SAH in both humans and rats suggested a possible relationship between PK2 and SAH pathology. PK2 knockdown promoted an A1 astrocytic phenotype with upregulation of neurodegenerative indicators, while intravascular injection of recombinant PK2 (rPK2) promoted A2 astrocytic phenotype and reduced SAH-induced neuronal injury and behavioral dysfunction. Finally, we identified that tumor necrosis factor alpha (TNF-α) was sufficient to elevate the protein level of PK2 in neurons and enhance astrocytic activation in vitro. Moreover, rPK2 selectively promoted astrocytic polarization to an A2 phenotype under a TNF-α stimulus and induced phosphorylation of signal transducer and activator of transcription 3 (STAT3), suggesting that SAH-induced increases in PK2 may function as an endogenous mechanism for self-repair. Collectively, our findings support that enhancing PK2 expression or administration of rPK2 may induce a selective modulation of astrocytic polarization to a protective phenotype following SAH-like stimuli.

Precision Medicine in Acute Brain Injury: A Narrative Review

Over the past few years, the concept of personalized medicine has percolated into the management of different neurological conditions. Improving outcomes after acute brain injury (ABI) continues to be a major challenge. Unrecognized individual multiomic variations in addition to multiple interacting processes may explain why we fail to observe comprehensive improvements in ABI outcomes even when applied treatments appear to be beneficial logically. The provision of clinical care based on a multiomic approach may revolutionize the management of traumatic brain injury, delayed cerebral ischemia after subarachnoid hemorrhage, acute ischemic stroke, and several other neurological diseases. The challenge is to incorporate all the information obtained from genomic studies, other omic data, and individual variability into a practical tool that can be used to assist clinical decision-making. The effective execution of such strategies, which is still far away, requires the development of protocols on the basis of these complex interactions and strict adherence to management protocols. In this review, we will discuss various omics and physiological targets to guide individualized patient management after ABI.

Programmed Cell Deaths and Potential Crosstalk With Blood-Brain Barrier Dysfunction After Hemorrhagic Stroke

Hemorrhagic stroke is a life-threatening neurological disease characterized by high mortality and morbidity. Various pathophysiological responses are initiated after blood enters the interstitial space of the brain, compressing the brain tissue and thus causing cell death. Recently, three new programmed cell deaths (PCDs), necroptosis, pyroptosis, and ferroptosis, were also found to be important contributors in the pathophysiology of hemorrhagic stroke. Additionally, blood-brain barrier (BBB) dysfunction plays a crucial role in the pathophysiology of hemorrhagic stroke. The primary insult following BBB dysfunction may disrupt the tight junctions (TJs), transporters, transcytosis, and leukocyte adhesion molecule expression, which may lead to brain edema, ionic homeostasis disruption, altered signaling, and immune infiltration, consequently causing neuronal cell death. This review article summarizes recent advances in our knowledge of the mechanisms regarding these new PCDs and reviews their contributions in hemorrhagic stroke and potential crosstalk in BBB dysfunction. Numerous studies revealed that necroptosis, pyroptosis, and ferroptosis participate in cell death after subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH). Endothelial dysfunction caused by these three PCDs may be the critical factor during BBB damage. Also, several signaling pathways were involved in PCDs and BBB dysfunction. These new PCDs (necroptosis, pyroptosis, ferroptosis), as well as BBB dysfunction, each play a critical role after hemorrhagic stroke. A better understanding of the interrelationship among them might provide us with better therapeutic targets for the treatment of hemorrhagic stroke.

Estrogen receptor alpha gene variant, PvuII (rs2234693), as a potential pharmacogenetic biomarker for aneurysmal subarachnoid hemorrhage in postmenopausal women

Aneurysmal subarachnoid hemorrhage (aSAH) occurs more often in postmenopausal women than in men. Estrogen plays an important role in vascular homeostasis. Our aim was to elucidate whether a drop in circulating estradiol in conjunction with variants of estrogen receptor genes have a role in female gender susceptibility to aSAH. A total of 709 subjects were enrolled (349 aSAH patients, 360 controls) and genotyped for rs2234693 or PvuII (intron 1, T>C) in the ESR1 gene and rs4986938 or AluI (exon 8, 1730G>A) of ESR2 gene by PCR-RFLP. Serum estradiol was estimated by ELISA. Estrogen receptor gene expression was studied by qRT-PCR. Logistic regression analysis indicated a significant recessive effect of the T allele of PvuII on aSAH in females, and this association remained statistically significant even after adjusting for confounders (OR 1.702, CI 95% 1.062, 2.726, P value = 0.027). ESR1 gene expression was significantly reduced (P value = 0.0089) in subjects carrying PvuII T allele. In postmenopausal women with TT genotype and low serum estradiol, the odds for developing aSAH were found to be 3.5-fold increase compared with premenopausal women (CI 95% 1.424-8.828, P value = 0.0074). However, this variant showed no significant association with aSAH in men. No significant difference was found in genotype and allelic distribution of AluI polymorphism in ESR2 gene, between patients and controls. We propose that the PvuII T allele could be a potential pharmacogenetic marker for strategizing personal medicine for preventing aSAH in postmenopausal women with low circulating estradiol. Further larger studies in other population are warranted.