Potential role of aspirin in the prevention of aneurysmal subarachnoid hemorrhage

Aspirin treatment for unruptured intracranial aneurysms: Focusing on its anti-inflammatory role

Intracranial aneurysms (IAs), as a common cerebrovascular disease, claims a worldwide morbidity rate of 3.2%. Inflammation, pivotal in the pathogenesis of IAs, influences their formation, growth, and rupture. This review investigates aspirin's modulation of inflammatory pathways within this context. With IAs carrying significant morbidity and mortality upon IAs rupture and current interventions limited to surgical clipping and endovascular coiling, the quest for pharmacological options is imperative. Aspirin's role in cardiovascular prevention, due to its anti-inflammatory effects, presents a potential therapeutic avenue for IAs. In this review, we examine aspirin's efficacy in experimental models and clinical settings, highlighting its impact on the progression and rupture risks of unruptured IAs. The underlying mechanisms of aspirin's impact on IAs are explored, with its ability examined to attenuate endothelial dysfunction and vascular injury. This review may provide a theoretical basis for the use of aspirin, suggesting a promising strategy for IAs management. However, the optimal dosing, safety, and long-term efficacy remain to be established. The implications of aspirin therapy are significant in light of current surgical and endovascular treatments. Further research is encouraged to refine aspirin's clinical application in the management of unruptured IAs, with the ultimate aim of reducing the incidence of aneurysms rupture.

Aspin: neurosurgical aspirin intervention prognostic study - perioperative continuation versus discontinuation of aspirin in lumbar spinal surgery, a randomized controlled, noninferiority trial

RATIONALE

Aspirin is typically discontinued in cranial and spinal surgery because of the increased risk of hemorrhagic complications, but comes together with the risk of resulting in an increase of cardiac and neurologic thrombotic perioperative events.

OBJECTIVE

The aim of this study is to investigate the non-inferiority of perioperative continuation of aspirin patients undergoing low complex lumbar spinal surgery, compared with the current policy of perioperative discontinuation of aspirin.

STUDY DESIGN

A randomized controlled trial with two parallel groups of 277 cases (554 in total).

STUDY POPULATION

Patients undergoing low complex lumbar spinal surgery and using aspirin. All patients are aged >18 years.

INTERVENTION

Peri-operative continuation of aspirin.

STUDY OUTCOMES

Primary study outcome: composite of the following bleeding complications: Neurological deterioration as a result of hemorrhage in the surgical area with cauda and/or nerve root compression. Post-surgical anemia with hemoglobin level lower than 5 mmol/l, requiring transfusion. Subcutaneous hematoma leading to wound leakage and pain higher than NRS=7. Major and/or minor hemorrhage in any other body system according to the definition of the International Society on Thrombosis and Haemostasis bleeding scale. Secondary study outcomes: Each of the individual components of the primary outcome Absolute mean difference in operative blood loss between the study arms Thrombo-embolic-related complications: Myocardial infarction Venous thromboembolism Stroke Arterial thromboembolism FURTHER STUDY OUTCOMES: Anticoagulant treatment satisfaction by the Anti-Clot Treatment Scale (ACTS) and general health by the Patient-Reported Outcomes Measurement Information System (PROMIS Global-10) in the pre- and postoperative phase. NATURE AND EXTENT OF THE BURDEN AND RISKS ASSOCIATED WITH PARTICIPATION, BENEFIT, AND GROUP RELATEDNESS: Participation in this study imposes no additional risk to patients. Currently, there is no consensus on whether or not aspirin should be discontinued before cranial or spinal surgery. Currently, aspirin is typically discontinued in cranial and spinal surgery, because of a potential increased risk of hemorrhagic complication. An argument not based on a clinical trial. However, this policy might delay surgical procedures or carry the risk of resulting in an increase in cardiac and neurologic thrombotic perioperative events. It is unclear if the possibility of an increase in hemorrhage-related complications outweighs the risk of an increase in cardiac and neurologic thrombotic perioperative events. Furthermore, the Data Safety Monitoring Board (DSMB) will be asked for safety analysis by monitoring the study. There are no further disadvantages to participating in this study. Outcome measurements are recorded during admission and regular outpatient visits, and thus, do not require additional visits to the hospital.

Antiplatelet medications and intracranial hemorrhage in patients with primary brain tumors

BACKGROUND

Spontaneous intracranial hemorrhage (ICH) is a frequent and severe consequence of primary brain tumors. The safety of antiplatelet medications in this patient population is undefined.

OBJECTIVE

The primary objective was to determine whether antiplatelet medications are associated with an increased risk of ICH in patients with primary brain tumors.

PATIENTS/METHODS

We performed a matched, retrospective cohort study of patients with the diagnosis of primary brain tumor treated at our institution between 2010 and 2021. Radiographic images of all potential ICH events underwent blinded review. The primary end point of the study was the cumulative incidence of ICH at 1 year after tumor diagnosis.

RESULTS AND CONCLUSIONS

A total of 387 patients with primary brain tumors were included in the study population (130 exposed to antiplatelet agents, 257 not exposed). The most common malignancy was glioblastoma (n = 256, 66.1%). Among the intervention cohort, 119 patients received aspirin monotherapy. The cumulative incidence of any ICH at 1 year was 11.0% (95% CI, 5.3-16.6) in those receiving antiplatelet medications and 13.0% (95% CI, 8.5-17.6) in those not receiving antiplatelet medications (Gray test, p = 0.6). The cumulative incidence of major ICH was similar between the cohorts (3.3% in antiplatelet cohort vs 2.9% in control cohort, p = 1.0). This study did not identify an increased incidence of ICH in patients with primary brain tumors exposed to antiplatelet medications.

Antithrombotic agent usage before ictus in aneurysmal subarachnoid hemorrhage: relation to hemorrhage severity, clinical course, and outcome

BACKGROUND

The number of patients with aneurysmal subarachnoid hemorrhage (aSAH) who are on antithrombotic agents before ictus is rising. However, their effect on early brain injury and disease development remains unclear. The primary aim of this study was to determine if antithrombotic agents (antiplatelets and anticoagulants) were associated with a worse initial hemorrhage severity, rebleeding rate, clinical course, and functional recovery after aSAH.

METHODS

In this observational study, those 888 patients with aSAH, treated at the neurosurgical department, Uppsala University Hospital, between 2008 and 2018 were included. Demographic, clinical, radiological (Fisher and Hijdra score), and outcome (Extended Glasgow Outcome Scale one year post-ictus) variables were assessed.

RESULTS

Out of 888 aSAH patients, 14% were treated with antithrombotic agents before ictus. Seventy-five percent of these were on single therapy of antiplatelets, 23% on single therapy of anticoagulants, and 3% on a combination of antithrombotic agents. Those with antithrombotic agents pre-ictus were significantly older and exhibited more co-morbidities and a worse coagulation status according to lab tests. Antithrombotic agents, both as one group and as subtypes (antiplatelets and anticoagulants), were not associated with hemorrhage severity (Hijdra score/Fisher) nor rebleeding rate. The clinical course did not differ in terms of delayed ischemic neurological deficits or last-tier treatment with thiopental and decompressive craniectomy. These patients experienced a higher mortality and lower rate of favorable outcome in univariate analyses, but this did not hold true in multiple logistic regression analyses after adjustment for age and co-morbidities.

CONCLUSIONS

After adjustment for age and co-morbidities, antithrombotic agents before aSAH ictus were not associated with worse hemorrhage severity, rebleeding rate, clinical course, or long-term functional recovery.

Risk factor management matters more than pharmaceutical cyclooxygenase-2 inhibition in the prevention of de novo intracranial aneurysms

BACKGROUND AND PURPOSE

Pathophysiological studies of saccular intracranial aneurysm (sIA) disease have shown that inflammation plays a crucial role in sIA development. Pharmaceutical inhibition of COX-2-PGE2-NF-κB signaling (COX-2, cyclooxygenase-2; PGE2, prostaglandin E2; NF-κB, nuclear factor κB) has been shown in animal models to inhibit sIA formation and progression suggesting that use of medication inhibiting COX-2 could reduce intracranial aneurysm formation also in patients.

METHODS

The impact of COX-2 inhibition on de novo sIA formation was studied in two cohorts: in a previously described angiographically followed cohort of 1419 sIA patients and in a cohort of 117 sIA patients treated with stenting or stent-assisted embolization. Patients were identified from our population-based Kuopio Intracranial Aneurysm Database. Data on the use of anti-inflammatory medications and hospital diagnoses were obtained from national registries. Risk factors were identified by univariate and multivariate analyses.

RESULTS

De novo sIA patients were younger and more often smokers. Use of COX-2 selective inhibitors or nonsteroidal anti-inflammatory drugs did not significantly reduce de novo sIA formation, but the percentage of patients with de novo sIA formation was smaller in patients with prescribed regular acetylsalicylic acid medication (1.1% vs. 3.6%). In the multivariate analysis, however, neither acetylsalicylic acid use nor other type of pharmaceutical inhibition of COX-2 reduced the formation of de novo sIAs. The risk was mostly affected by age, smoking history and irregular usage of antihypertensive medication regardless of used COX-2 inhibition level.

CONCLUSION

For the prevention of de novo sIA formation, risk factor management with focus on cessation of smoking and treating hypertension adequately seems more important than pharmaceutical COX-2 inhibition.

Aspirin treatment prevents inflammation in experimental bifurcation aneurysms in New Zealand White rabbits

BACKGROUND

Aneurysm wall degeneration is linked to growth and rupture. To address the effect of aspirin (ASA) on aneurysm formation under various wall conditions, this issue was analyzed in a novel rabbit bifurcation model.

METHODS

Bifurcation aneurysms created in 45 New Zealand White rabbits were randomized to vital (n=15), decellularized (n=13), or elastase-degraded (n=17) wall groups; each group was assigned to a study arm with or without ASA. At follow-up 28 days later, aneurysms were evaluated for patency, growth, and wall inflammation at macroscopic and histological levels.

RESULTS

36 rabbits survived to follow-up at the end of the trial. None of the aneurysms had ruptured. Patency was visualized in all aneurysms by intraoperative fluorescence angiography and confirmed in 33 (92%) of 36 aneurysms by MRI/MRA. Aneurysm size was significantly increased in the vital (without ASA) and elastase-degraded (with and without ASA) groups. Aneurysm thrombosis was considered complete in three (50%) of six decellularized aneurysms without ASA by MRI/MRA. Locoregional inflammation of the aneurysm complex was significantly reduced in histological analysis among all groups treated with ASA.

CONCLUSION

ASA intake prevented inflammation of both the periadventitial tissue and aneurysm wall, irrespective of initial wall condition. Although ASA prevented significant growth in aneurysms with vital walls, this preventive effect did not have an important role in elastase-degraded pouches. In possible translation to the clinical situation, ASA might exert a potential preventive effect during early phases of aneurysm formation in patients with healthy vessels but not in those with highly degenerative aneurysm walls.

Disturbed flow's impact on cellular changes indicative of vascular aneurysm initiation, expansion, and rupture: A pathological and methodological review

Aneurysms are malformations within the arterial vasculature brought on by the structural breakdown of the microarchitecture of the vessel wall, with aneurysms posing serious health risks in the event of their rupture. Blood flow within vessels is generally laminar with high, unidirectional wall shear stressors that modulate vascular endothelial cell functionality and regulate vascular smooth muscle cells. However, altered vascular geometry induced by bifurcations, significant curvature, stenosis, or clinical interventions can alter the flow, generating low stressor disturbed flow patterns. Disturbed flow is associated with altered cellular morphology, upregulated expression of proteins modulating inflammation, decreased regulation of vascular permeability, degraded extracellular matrix, and heightened cellular apoptosis. The understanding of the effects disturbed flow has on the cellular cascades which initiate aneurysms and promote their subsequent growth can further elucidate the nature of this complex pathology. This review summarizes the current knowledge about the disturbed flow and its relation to aneurysm pathology, the methods used to investigate these relations, as well as how such knowledge has impacted clinical treatment methodologies. This information can contribute to the understanding of the development, growth, and rupture of aneurysms and help develop novel research and aneurysmal treatment techniques.

Unruptured cerebral aneurysms in elderly patients: key challenges and management

Unruptured cerebral aneurysms are increasingly identified in elderly patients as the global life expectancy continues to rise and non-invasive vascular imaging becomes more prevalent. The optimal management of unruptured aneurysms in elderly patients remains controversial. Variability in life expectancy, comorbidities and rupture risk coupled with heterogenous endovascular and surgical treatments contribute to a paucity of clear guidelines, and current management is highly individualized. Elderly patients present unique considerations including frailty, cognitive dysfunction, vasculopathy, reduced life expectancy and overall worse prognosis in case of rupture which shape the risks and likelihood of success of endovascular and microsurgical treatment. In this review, we provide a comprehensive overview of unruptured cerebral aneurysms in the elderly, with a particular focus on the natural history, key challenges associated with advanced age, management and future innovations to further refine treatment.Key MessagesThe management of unruptured cerebral aneurysms in elderly patients remains controversial.Key challenges including frailty, cognitive dysfunction, reduced life expectancy, vasculopathy and poor prognosis with aneurysm rupture add complexity to endovascular and surgical decision making not encountered with younger demographics.A thorough understanding of available treatment options, likelihood of treatment success and associated risks weighed against the risk of aneurysm rupture informs patient discussion and management.

Decreased contrast enhancement on high-resolution vessel wall imaging of unruptured intracranial aneurysms in patients taking aspirin

OBJECTIVE

Inflammation plays an integral role in the formation, growth, and progression to rupture of unruptured intracranial aneurysms (UIAs). Animal and human studies have suggested that, due to its antiinflammatory effect, aspirin (ASA) may decrease the risks of growth and rupture of UIAs. High-resolution vessel wall imaging (HR-VWI) has emerged as a noninvasive method to assess vessel wall inflammation and UIA instability. To the authors' knowledge, to date no studies have found a significant correlation between patient use of ASA and contrast enhancement of UIAs on HR-VWI.

METHODS

The University of Iowa HR-VWI Project database was analyzed. This database is a compilation of data on patients with UIAs who prospectively underwent HR-VWI on a 3T Siemens MRI scanner. The presence of aneurysmal wall enhancement was objectively defined using the aneurysm-to-pituitary stalk contrast ratio (CRstalk). This ratio was calculated by measuring the maximal signal intensity in the aneurysmal wall and the pituitary stalk on postcontrast T1-weighted images. Data on aneurysm size, morphology, and location and patient demographics and comorbidities were collected. Use of ASA was defined as daily intake of ≥ 81 mg during the previous 6 months or longer. Univariate and multivariate logistic regression analyses were performed to determine factors independently associated with increased contrast enhancement of UIAs on HR-VWI.

RESULTS

In total, 74 patients harboring 96 UIAs were included in the study. The mean patient age was 64.7 ± 12.4 years, and 60 patients (81%) were women. Multivariate analysis showed that age (OR 1.12, 95% CI 1.05-1.19), aneurysm size ≥ 7 mm (OR 21.3, 95% CI 4.88-92.8), and location in the anterior communicating, posterior communicating, and basilar arteries (OR 10.7, 95% CI 2.45-46.5) were significantly associated with increased wall enhancement on HR-VWI. On the other hand, use of ASA was significantly associated with decreased aneurysmal wall enhancement on HR-VWI (OR 0.22, 95% CI 0.06-0.83, p = 0.026).

CONCLUSIONS

The study results establish a correlation between use of ASA daily for ≥ 6 months and significant decreases in wall enhancement of UIAs on HR-VWI. The findings also demonstrate that detection of wall enhancement using HR-MRI may be a valuable noninvasive method for assessing aneurysmal wall inflammation and UIA instability.

Disruption of P2X4 purinoceptor and suppression of the inflammation associated with cerebral aneurysm formation

OBJECTIVE

There are no effective therapeutic drugs for cerebral aneurysms, partly because the pathogenesis remains unresolved. Chronic inflammation of the cerebral arterial wall plays an important role in aneurysm formation, but it is not clear what triggers the inflammation. The authors have observed that vascular endothelial P2X4 purinoceptor is involved in flow-sensitive mechanisms that regulate vascular remodeling. They have thus hypothesized that shear stress-associated hemodynamic stress on the endothelium causes the inflammatory process in the cerebral aneurysm development.

METHODS

To test their hypothesis, the authors examined the role of P2X4 in cerebral aneurysm development by using P2X4-/- mice and rats that were treated with a P2X4 inhibitor, paroxetine, and subjected to aneurysm-inducing surgery. Cerebral aneurysms were induced by unilateral carotid artery ligation and renovascular hypertension.

RESULTS

The frequency of aneurysm induction evaluated by light microscopy was significantly lower in the P2X4-/- mice (p = 0.0488) and in the paroxetine-treated male (p = 0.0253) and female (p = 0.0204) rats compared to control mice and rats, respectively. In addition, application of paroxetine from 2 weeks after surgery led to a significant reduction in aneurysm size in the rats euthanized 3 weeks after aneurysm-inducing surgery (p = 0.0145), indicating that paroxetine suppressed enlargement of formed aneurysms. The mRNA and protein expression levels of known inflammatory contributors to aneurysm formation (monocyte chemoattractant protein-1 [MCP-1], interleukin-1β [IL-1β], tumor necrosis factor-α [TNFα], inducible nitric oxide synthase [iNOS], and cyclooxygenase-2 [COX-2]) were all significantly elevated in the rats that underwent the aneurysm-inducing surgery compared to the nonsurgical group, and the values in the surgical group were all significantly decreased by paroxetine administration according to quantitative polymerase chain reaction techniques and Western blotting. Although immunolabeling densities for COX-2, iNOS, and MCP-1 were not readily observed in the nonsurgical mouse groups, such densities were clearly seen in the arterial wall of P2X4+/+ mice after aneurysm-inducing surgery. In contrast, in the P2X4-/- mice after the surgery, immunolabeling of COX-2 and iNOS was not observed in the arterial wall, whereas that of MCP-1 was readily observed in the adventitia, but not the intima.

CONCLUSIONS

These data suggest that P2X4 is required for the inflammation that contributes to both cerebral aneurysm formation and growth. Enhanced shear stress-associated hemodynamic stress on the vascular endothelium may trigger cerebral aneurysm development. Paroxetine may have potential for the clinical treatment of cerebral aneurysms, given that this agent exhibits efficacy as a clinical antidepressant.

Management of Small Unruptured Intracranial Aneurysms: To Treat or Not to Treat?

Unruptured intracranial aneurysms measuring <7 mm in diameter have become increasingly prevalent due to advances in diagnostic imaging. The most feared complication is aneurysm rupture leading to a subarachnoid hemorrhage. Based on the current literature, the 3 main treatments for an unruptured intracranial aneurysm are conservative management with follow-up imaging, endovascular coiling, or surgical clipping. However, there remains no consensus on the best treatment approach. The natural history of the aneurysm and risk factors for aneurysm rupture must be considered to individualize treatment. Models including population, hypertension, age, size of aneurysm, earlier subarachnoid hemorrhage from a prior aneurysm, site of aneurysm score, Unruptured Intracranial Aneurysm Treatment Score, and advanced neuroimaging can assist physicians in assessing the risk of aneurysm rupture. Macrophages and other inflammatory modulators have been elucidated as playing a role in intracranial aneurysm progression and eventual rupture. Further studies need to be conducted to explore the effects of therapeutic drugs targeting inflammatory modulators.

Aspirin associated with decreased rate of intracranial aneurysm growth

OBJECTIVE

Aspirin has emerged as a potential agent in the prevention of rupture of intracranial aneurysms (IAs). In this study, the authors' goal was to test if aspirin is protective against aneurysm growth in patients harboring multiple IAs ≤ 5 mm.

METHODS

The authors performed a retrospective review of a prospectively maintained database covering the period July 2009 through January 2019. Patients' data were included if the following criteria were met: 1) the patient harbored multiple IAs; 2) designated primary aneurysms were treated by surgical/endovascular means; 3) the remaining aneurysms were observed for growth; and 4) a follow-up period of at least 5 years after the initial treatment was available. Demographics, earlier medical history, the rupture status of designated primary aneurysms, aneurysms' angiographic features, and treatment modalities were gathered.

RESULTS

The authors identified 146 patients harboring a total of 375 IAs. At the initial encounter, 146 aneurysms were treated and the remaining 229 aneurysms (2-5 mm) were observed. During the follow-up period, 24 (10.48%) of 229 aneurysms grew. All aneurysms observed to grow later underwent treatment. None of the observed aneurysms ruptured. Multivariate analysis showed that aspirin was significantly associated with a decreased rate of growth (odds ratio [OR] 0.19, 95% confidence interval [CI] 0.05-0.63). Variables associated with an increased rate of growth included hypertension (OR 14.38, 95% CI 3.83-53.94), drug abuse (OR 11.26, 95% CI 1.21-104.65), history of polycystic kidney disease (OR 9.48, 95% CI 1.51-59.35), and subarachnoid hemorrhage at presentation (OR 5.91, 95% CI 1.83-19.09).

CONCLUSIONS

In patients with multiple IAs, aspirin significantly decreased the rate of aneurysm growth over time. Additional prospective interventional studies are needed to validate these findings.

Pathophysiology of Intracranial Aneurysms

Background and Purpose:

The pathophysiology of development, growth, and rupture of intracranial aneurysms (IAs) is only partly understood. Cyclooxygenase 2 (COX-2) converts arachidonic acid to prostaglandin H 2 , which, in turn, is isomerized to prostaglandin E 2 . In the human body, COX-2 plays an essential role in inflammatory pathways. This explorative study aimed to investigate COX-2 expression in the wall of IAs and its correlation to image features in clinical (1.0T, 1.5T, and 3.0T) magnetic resonance imaging (MRI) and ultra-high-field 7T MRI.

Methods:

The study group comprised 40 patients with partly thrombosed saccular IAs. The cohort included 17 ruptured- and 24 unruptured IAs, which had all been treated microsurgically. Formaldehyde-fixed paraffin-embedded samples were immunohistochemically stained with a monoclonal antibody against COX-2 (Dako, Santa Clara, CA; Clone: CX-294). We correlated Perls Prussian blue staining, MRI, and clinical data with immunohistochemistry, analyzed using the Trainable Weka Segmentation algorithm.

Results:

Aneurysm dome size ranged between 2 and 67 mm. The proportion of COX-2 positive cells ranged between 3.54% to 85.09%. An upregulated COX-2 expression correlated with increasing IA dome size ( P =0.047). Furthermore, there was a tendency of higher COX-2 expression in most ruptured IAs ( P =0.064). At all field strengths, MRI shows wall hypointensities due to iron deposition correlating with COX-2 expression ( P =0.022).

Conclusions:

Iron deposition and COX-2 expression in IAs walls correlate with signal hypointensity in MRI, which might, therefore, serve as a biomarker for IA instability. Furthermore, as COX-2 was also expressed in small unruptured IAs, it could be a potential target for specific medical treatment.

Epigenetic mechanisms of neurodegenerative diseases and acute brain injury

Epigenetic modifications are emerging as major players in the pathogenesis of neurodegenerative disorders and susceptibility to acute brain injury. DNA and histone modifications act together with non-coding RNAs to form a complex gene expression machinery that adapts the brain to environmental stressors and injury response. These modifications influence cell-level operations like neurogenesis and DNA repair to large, intricate processes such as brain patterning, memory formation, motor function and cognition. Thus, epigenetic imbalance has been shown to influence the progression of many neurological disorders independent of aberrations in the genetic code. This review aims to highlight ways in which epigenetics applies to several commonly researched neurodegenerative diseases and forms of acute brain injury as well as shed light on the benefits of epigenetics-based treatments.

Evaluation of subacute subarachnoid haemorrhage detection using a magnetic resonance imaging sequence: Double inversion recovery

BACKGROUND AND OBJECTIVES

The diagnosis of subarachnoid hemorrhage (SAH) especially at the subacute stage is still a challenging issue using the conventional imaging modalities. Here we evaluated the role of double inversion recovery (DIR) sequence of MRI compared with the conventional gradient-recalled echo (GRE)-T2*-W and susceptibility-weighted imaging (SWI) sequences in the diagnosis of subacute SAH.

MATERIALS AND METHODS

This prospective study was conducted on 21 patients with SAH, which were diagnosed using CT scan at the initial step. In the third week after the injury (14-20 days), all patients underwent a brain MRI exam that included T2*-W, SWI, and DIR imaging sequences. All images were independently read by two radiologists, who were blinded to the clinical history of the patients. The presence or absence of SAH was reviewed and assessed in 6 anatomical regions.

RESULTS

On the DIR images, 20 patients were found to have at least one subarachnoid signal abnormality, while the SWI and T2*-W images identified SAH areas on 17 and 15 patients, respectively. The highest rate of inter-observer consensus by the DIR sequence was found in the interhemispheric fissure and perimesencephalic area (k = 1). Also, a highest rate of inter-observer consensus using SWI was found in the interhemispheric fissure and posterior fossa cistern area (k = 1). A weak agreement was found in frontal-parietal convexity using SWI (k = 0.447), and in posterior fossa cistern by the T2* sequence (k = 0.447).

CONCLUSION

In conclusion, the DIR sequence was more reliable at identifying signal abnormalities in subacute SAH patients than the T2*-W and SWI sequence, and is suggested as a promising imaging technique for detecting hemorrhagic areas without considering the anatomical distribution of SAH.

Nonsteroidal Anti-Inflammatory Drugs: A Potential Pharmacological Treatment for Intracranial Aneurysm

Background

Saccular intracranial aneurysms (IAs) are outpouchings of the vessel wall of intracranial arteries. Rupture of IAs results in subarachnoid hemorrhage which is associated with high morbidity and mortality. Surgical interventions, such as clipping and coiling, have associated risks. Currently, there are no proven pharmacological treatments to prevent the growth or rupture of IAs. Infiltration of proinflammatory cytokines in response to increased wall sheer stress is a hallmark of IA. Nonsteroidal anti-inflammatory drugs (NSAIDs) are being investigated as potential therapeutic agents for reduction in growth and/or prevention of IA through inhibition of inflammatory pathways.

Summary

This review will discuss the role of NSAIDs in attenuating the inflammation that drives IA progression and rupture. There are two main subtypes of NSAIDs, nonselective COX and selective COX-2 inhibitors, both of which have merit in treating IA. Evidence will be presented which shows that NSAIDs inhibit several key inflammatory mediators involved in IA progression including nuclear factor-κB, tumor necrosis factor-α, and matrix metalloproteinases. In addition, the role of NSAIDs in limiting inflammatory cell adhesion to endothelial cells and attenuating endothelial cell senescence will be discussed.

Key Messages

There is an abundance of basic science and preclinical data that support NSAIDs as a promising treatment for IA. Additionally, a combination treatment strategy of low-dose aspirin given concomitantly with a selective COX-2 inhibitor may result in a reduced side effect profile compared to aspirin or selective COX-2 inhibitor use alone. Several large clinical trials are currently planned to further investigate the efficacy of NSAIDs as an effective nonsurgical treatment for IAs.

Association between aspirin dose and subarachnoid hemorrhage from saccular aneurysms: A case-control study

OBJECTIVE

To determine the association between ruptured saccular aneurysms and aspirin use/aspirin dose.

METHODS

Four thousand seven hundred one patients who were diagnosed at the Massachusetts General Hospital and Brigham and Women's Hospital between 1990 and 2016 with 6,411 unruptured and ruptured saccular intracranial aneurysms were evaluated. Univariable and multivariable logistic regression analyses were performed to determine the association between aneurysmal subarachnoid hemorrhage and aspirin use, including aspirin dose. Inverse probability weighting using propensity scores was used to adjust for potential differences in baseline characteristics between cases and controls. Additional analyses were performed to examine the association of aspirin use and rerupture before treatment.

RESULTS

In multivariate analysis with propensity score weighting, aspirin use (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.45-0.80) was significantly associated with decreased risk of ruptured intracranial aneurysms. There was a significant inverse dose-response relationship between aspirin dose and aneurysmal subarachnoid hemorrhage (OR 0.65, 95% CI 0.53-0.81). In contrast, there was a significant association between aspirin use and increased risk of rerupture before treatment (OR 8.15, 95% CI 2.22-30.0).

CONCLUSIONS

In this large case-control study, aspirin therapy at diagnosis was associated with a significantly decreased risk of subarachnoid hemorrhage, with an inverse dose-response relationship among aspirin users. However, once rupture has occurred, aspirin is associated with an increased risk of rerupture before treatment.

Neurocognitive outcomes after aneurysmal subarachnoid hemorrhage: Identifying inflammatory biomarkers

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe type of stroke which carries a high case-fatality rate. Those who survive the ictus of aneurysm rupture harbor substantial risks of neurological morbidity, functional disability, and cognitive dysfunction. Although the pervasiveness of cognitive impairment is widely acknowledged as a long-term sequela of aSAH, the mechanisms underlying its development are poorly understood. The onset of aSAH elicits activation of the inflammatory cascade, and ongoing neuroinflammation is suspected to contribute to secondary complications, such as vasospasm and delayed cerebral ischemia. In this review, we analyze the extant literature regarding the relationship between neuroinflammation and cognitive dysfunction after aSAH. Pro-inflammatory cytokines appear to play a role in maintaining normal cognitive function in adults unaffected by aSAH. However, in the setting of aSAH, elevated cytokine levels may correlate with worse neuropsychological outcomes. This seemingly dichotomous relationship between neuroinflammation and cognition suggests that the action of cytokines varies, depending on their physiologic environment. Experimental therapies which suppress the immune response to aSAH appear to have a beneficial effect on cognitive outcomes. However, further studies are necessary to determine the utility of inflammatory mediators as biomarkers of neurocognitive outcomes, as well as their role in the management of aSAH.

Higher leukocyte count predicts 3-month poor outcome of ruptured cerebral aneurysms

It is not fully established whether leukocyte can predict the poor outcome for ruptured cerebral aneurysms (CA) or not. Here, we retrospectively analyzed the clinical data of 428 patients with ruptured CA between 2010 and 2015. Patients’ demographic data, including gender, age, history of smoking, alcohol, hypertension, diabetes and hypercholesterolemia, Hunt-Hess and Fisher grade, occurrence of hydrocephalus, aneurysm location, time to surgery, delayed ischemic neurological deficit (DIND) and peak leukocyte of blood test from day 1 to 3 after aneurysmal rupture were recorded and analyzed. In the multivariable analysis model, gender, Fisher grade, time to surgery and hydrocephalus were not relevant to poor outcome. However, Hunt-Hess grade, DIND and preoperative leukocyte count (>13.84 × 10⁹/L) were significantly associated with adverse outcome. The respective increased risks were 5.2- (OR 5.24, 95% CI 1.67–16.50, p = 0.005), 6.2-(OR 6.24, 95% CI 3.55–10.99, p < 0.001) and 10.9-fold (OR 10.93, 95% CI 5.98–19.97, p < 0.001). The study revealed that Hunt-Hess grade, DIND and preoperative leukocyte count (>13.84 × 10⁹/L) were independent risk factors for poor outcome of ruptured CA at 3 months. Higher leukocyte count is a convenient and useful marker to predict 3-month poor outcome for ruptured CA.

Thrombosed Aneurysm of the Posterior Inferior Cerebellar Artery and Lateral Medullary Ischemia as the Initial Presentation of Polyarteritis Nodosa: Case Report and Literature Review

A 27-year-old woman with a previously undiagnosed polyarteritis nodosa (PAN) developed lateral medullary stroke related to a thrombosed posterior inferior cerebellar artery (PICA)-origin aneurysm. A concurrent thrombosis of the PICA was identified on high-resolution 3-dimensional CUBE T1 magnetic resonance imaging sequence at 3 T. Body computed tomography angiography, magnetic resonance imaging-magnetic resonance angiography, and digital angiography revealed multiple tiny aneurysms of the visceral arteries and bilateral kidney infarcts. On the basis of these findings and of laboratory data, the patient was diagnosed as having PAN. Intracranial aneurysms (IAs) are extremely rare in PAN and usually manifest as subarachnoid or cerebral hemorrhage. Ischemic manifestation of small thrombosed IA is a rare occurrence. This case highlights (1) an uncommon complication in patients with PAN (16 other cases of IAs in patients with PAN found in the literature), (2) an unusual initial presentation of PAN, and (3) a thrombosed PICA-origin aneurysm responsible for an ischemic stroke and for secondary thrombosis of the parent vessel.

Macrophage Polarization in Cerebral Aneurysm: Perspectives and Potential Targets

Cerebral aneurysms (CAs) have become a health burden not only because their rupture is life threatening, but for a series of devastating complications left in survivors. It is well accepted that sustained chronic inflammation plays a crucial role in the pathology of cerebral aneurysms. In particular, macrophages have been identified as critical effector cells orchestrating inflammation in CAs. In recent years, dysregulated M1/M2 polarization has been proposed to participate in the progression of CAs. Although the pathological mechanisms of M1/M2 imbalance in CAs remain largely unknown, recent advances have been made in the understanding of the molecular basis and other immune cells involving in this sophisticated network. We provide a concise overview of the mechanisms associated with macrophage plasticity and the emerging molecular targets.

Low-dose aspirin and risk of intracranial bleeds

Objective:

To quantify the risk of intracranial bleeds (ICBs) associated with new use of prophylactic low-dose aspirin using a population-based primary care database in the United Kingdom.

Methods:

A cohort of new users of low-dose aspirin (75–300 mg; n = 199,079) aged 40–84 years and a 1:1 matched cohort of nonusers of low-dose aspirin at baseline were followed (maximum 14 years, median 5.4 years) to identify incident cases of ICB, with validation by manual review of patient records or linkage to hospitalization data. Using 10,000 frequency-matched controls, adjusted rate ratios (RRs) with 95% confidence intervals (CIs) were calculated for current low-dose aspirin use (0–7 days before the index date [ICB date for cases, random date for controls]); reference group was never used.

Results:

There were 1,611 cases of ICB (n = 743 for intracerebral hemorrhage [ICH], n = 483 for subdural hematoma [SDH], and n = 385 for subarachnoid hemorrhage [SAH]). RRs (95% CI) were 0.98 (0.84–1.13) for all ICB, 0.98 (0.80–1.20) for ICH, 1.23 (0.95–1.59) for SDH, and 0.77 (0.58–1.01) for SAH. No duration of use or dose–response association was apparent. RRs (95% CI) for ≥1 year of low-dose aspirin use were 0.90 (0.72–1.13) for ICH, 1.20 (0.91–1.57) for SDH, and 0.69 (0.50–0.94) for SAH.

Conclusion:

Low-dose aspirin is not associated with an increased risk of any type of ICB and is associated with a significantly decreased risk of SAH when used for ≥1 year.

Sex Differential in 15-Hydroxyprostaglandin Dehydrogenase Levels in the Lumen of Human Intracranial Aneurysms

BACKGROUND

Aspirin is a promising medical therapy for the prevention of intracranial aneurysm (IA) rupture. Recently, we found that men have a better response to aspirin than women. The purpose of this study was to determine whether a sex differential exists in the level of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in the lumen of human IAs.

METHODS AND RESULTS

Consecutive patients undergoing coiling or stent-assisted coiling for a saccular IA at our institution were enrolled. Two samples (A and B) were collected from IA lumens, and the plasma level of 15-PGDH was measured using an ELISA-based method. The study included 38 patients, with 20 women and 18 men. Women and men were comparable on baseline characteristics. The mean plasma concentration of 15-PGDH did not differ statistically between sample A (62.8±16.2 ng/mL) and sample B (61.8±17.9 ng/mL; 95% confidence interval -6.6 to 9.4). The mean plasma concentration of 15-PGDH in IA lumens of samples A and B was significantly higher in men (73.8±13.5 ng/mL) than women (49.6±7.8 ng/mL; P<0.0001).

CONCLUSIONS

Higher enzyme levels of 15-PGDH exist in the lumen of IAs of men compared with women. This observation could explain why aspirin confers better protection against IA rupture in men than in women. The susceptibility of an individual to aspirin may differ according to the level of 15-PGDH.

Double-barrel Y-configuration Stenting for Flow Diversion of a Giant Recurrent Basilar Apex Aneurysm with the Pipeline Flex Embolization Device

Giant basilar apex aneurysms are extremely challenging to successfully manage. The Pipeline Flex embolization device (PFED) is a new generation flow-diverting stent with a modified delivery system which allows resheathing of the stent after partial deployment. We describe a case of double-barrel Y-configuration stenting of a giant, recurrent basilar apex aneurysm using the PFED. A 73-year-old male was previously treated for an unruptured 11-mm basilar apex aneurysm with stent-assisted coiling using a Neuroform stent. The aneurysm was retreated twice with repeat coiling. After the third recurrence and persistent aneurysm growth into a giant, symptomatic lesion, we decided to proceed with flow diversion. We performed Y-stenting of the basilar bifurcation using three PFEDs, and was recoiled the aneurysm sac. Due to the low porosity of the flow diverters, a side-by-side double-barrel configuration was necessary in the basilar artery. Without the PFED's resheathable capability, it would not have been possible to perform Y-stenting with flow diverters.

Differential Sex Response to Aspirin in Decreasing Aneurysm Rupture in Humans and Mice

We previously found that aspirin decreases the risk of cerebral aneurysm rupture in humans. We aim to assess whether a sex differential exists in the response of human cerebral aneurysms to aspirin and confirm these observations in a mouse model of cerebral aneurysm. A nested case-control analysis from the International Study of Unruptured Intracranial Aneurysms was performed to assess whether a sex differential exists in the response of human cerebral aneurysms to aspirin. A series of experiments were subsequently performed in a mouse model of cerebral aneurysms. Aneurysms were induced with hypertension and elastase injection into mice basal cisterns. We found that aspirin decreased the risk of aneurysm rupture more significantly in men than in women in the International Study of Unruptured Intracranial Aneurysms. In mice, aspirin and cyclooxygenase-2 inhibitor did not affect cerebral aneurysm formation but significantly decreased the incidence of rupture. The incidence of rupture was significantly lower in male versus female mice on aspirin. Gene expression analysis from cerebral arteries showed higher 15-hydroxyprostaglandin dehydrogenase levels in male mice. The rate of cerebral aneurysm rupture was similar in male mice receiving aspirin and 15-hydroxyprostaglandin dehydrogenase inhibitor compared with females receiving aspirin and 15-hydroxyprostaglandin dehydrogenase agonist, signaling a reversal of the sex-differential response to aspirin. Aspirin decreases aneurysm rupture in human and mice, in part through cyclooxygenase-2 pathways. Evidence from animal and human studies suggests a consistent differential effect by sex. 15-Hydroxyprostaglandin dehydrogenase activation in females reduces the incidence of rupture and eliminates the sex-differential response to aspirin.

Neuroinflammation in Parkinson's disease and its potential as therapeutic target

Parkinson’s disease (PD), the second most common age-associated neurodegenerative disorder, is characterized by the loss of dopaminergic (DA) neurons and the presence of α-synuclein-containing aggregates in the substantia nigra pars compacta (SNpc). Chronic neuroinflammation is one of the hallmarks of PD pathophysiology. Post-mortem analyses of human PD patients and experimental animal studies indicate that activation of glial cells and increases in pro-inflammatory factor levels are common features of the PD brain. Chronic release of pro-inflammatory cytokines by activated astrocytes and microglia leads to the exacerbation of DA neuron degeneration in the SNpc. Besides, peripheral immune system is also implicated in the pathogenesis of PD. Infiltration and accumulation of immune cells from the periphery are detected in and around the affected brain regions of PD patients. Moreover, inflammatory processes have been suggested as promising interventional targets for PD and even other neurodegenerative diseases. A better understanding of the role of inflammation in PD will provide new insights into the pathological processes and help to establish effective therapeutic strategies. In this review, we will summarize recent progresses in the neuroimmune aspects of PD and highlight the potential therapeutic interventions targeting neuroinflammation.

Omental transplantation for neuroendocrinological disorders

Neurosurgical evidences show that the aging process is initiated between 25 to 30 years of age, in the arcuate nucleus of the hypothalamus. Likewise, experimental and neurosurgical findings indicate that the progressive ischemia in the arcuate nucleus and adjacent nuclei are responsibles at the onset of obesity and, type 2 diabetes mellitus in adults, and essential arterial hypertension (EAH). On the contrary, an omental transplantation on the optic chiasma, carotid bifurcation and anterior perforated space can provoke rejuvenation, gradual loss of body weight, decrease or normalization of hyperglycemia and normalization of EAH; all of them, due to revascularization of the hypothalamic nuclei. Besides, our surgical method have best advantages than the bariatric surgery, against obesity and type 2 diabetes mellitus.