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Reperfusion therapy is highly beneficial for ischemic stroke. Reduction in both infarct growth and edema are plausible mediators of clinical benefit with reperfusion. We aimed to quantify these mediators and their interrelationship.In a pooled, patient-level analysis of EXTEND-IA trials and SELECT study, we employed a mediation analysis framework to quantify infarct growth and cerebral edema(midline shift) mediation effect on successful reperfusion(mTICI≥2b) association with functional outcome(mRS distribution). Further, we evaluated an additional pathway to the original hypothesis, where infarct growth mediated successful reperfusion effect on midline shift.542/665(81.5%) eligible patients achieved successful reperfusion. Baseline clinical and imaging characteristics were largely similar between those achieving successful vs unsuccessful reperfusion. Median(IQR) infarct growth was 12.3(1.8-48.4)ml and median(IQR) midline shift was 0(0,2.2)mm. Of 249(37%) demonstrating a midline shift of ≥1mm, median(IQR) shift was 2.75(1.89, 4.21)mm). Successful reperfusion was associated with reductions in both predefined mediators; infarct growth (β, -1.19; 95%CI, -1.51to-0.88;p0.001) and midline shift (aOR:0.36,95%CI:0.23-0.57,p0.001). Successful reperfusion association with improved functional outcome (acOR:2.68; 95%CI:1.86-3.88,p0.001), became insignificant (acOR:1.39, 95%CI:0.95-2.04,p=0.094) when infarct growth and midline shift were added to the regression model. Infarct growth and midline shift explained 45% and 34% of successful reperfusion effect. Analysis considering alternative hypothesis demonstrated consistent results.In this mediation analysis from a pooled, patient-level cohort, a significant proportion(~80%) of successful reperfusion effect on functional outcome was mediated through reduction in infarct growth and cerebral edema. Further studies are required to confirm our findings, detect additional mediators to explain successful reperfusion residual effect and identify novel therapeutic targets to further enhance reperfusion benefits. This article is protected by copyright. All rights reserved.

Chronic subdural hematoma (CSDH) is an increasingly prevalent disease in the aging population. Patients with CSDH frequently suffer from concurrent vascular disease or develop secondary thrombotic complications requiring antithrombotic treatment.To determine the safety and impact of early reinitiation of antithrombotics after middle meningeal artery embolization for chronic subdural hematoma.This is a single-institution, retrospective study of patients who underwent middle meningeal artery (MMA) embolizations for CSDH. Patient with or without antithrombotic initiation within 5 days postembolization were compared. Primary outcome was the rate of recurrence within 60 days. Secondary outcomes included rate of reoperation, reduction in CSDH thickness, and midline shift.Fifty-seven patients met inclusion criteria. The median age was 66 years (IQR 58-76) with 21.1% females. Sixty-six embolizations were performed. The median length to follow-up was 20 days (IQR 14-44). Nineteen patients (33.3%) had rapid reinitiation of antithrombotics (5 antiplatelet, 11 anticoagulation, and 3 both). Baseline characteristics between the no antithrombotic (no-AT) and the AT groups were similar. The recurrence rate was higher in the AT group (no-AT vs AT, 9.3 vs 30.4%, P = .03). Mean absolute reduction in CSDH thickness and midline shift was similar between groups. Rate of reoperation did not differ (4.7 vs 8.7%, P = .61).Rapid reinitiation of AT after MMA embolization for CSDH leads to higher rates of recurrence with similar rates of reoperation. Care must be taken when initiating antithrombotics after treatment of CSDH with MMA embolization.

BACKGROUND Intracranial carotid sympathetic plexus (CSP) nerve sheath tumors have rarely been reported in the literature. This study describes the first reported case of a CSP neurofibroma and the first case of a CSP nerve sheath tumor treated via an endoscopic endonasal approach followed by adjuvant radiosurgery. OBSERVATIONS A 53-year-old man presented with 3 days of headaches and diplopia and was found to have a complete left abducens nerve palsy. Computed tomography (CT) revealed a smoothly dilated left carotid canal, CT angiography revealed a superiorly displaced left internal carotid artery (ICA), and magnetic resonance imaging revealed a T2-hyperintense and avidly enhancing lesion in the left cavernous sinus encasing the ICA. The patient underwent subtotal resection via an endoscopic transsphenoidal transcavernous approach followed by Gamma Knife radiosurgery. LESSONS Nerve sheath tumors arising from the CSP are extremely rare but need to be considered when assessing unusual cavernous sinus lesions. The clinical presentation is dependent on the anatomical location of the tumor and its relationship to the ICA. The optimal treatment paradigm is unknown.

Purpose Pituitary apoplexy can be a life threatening and vision compromising event. Antiplatelet and anticoagulation use has been reported as a contributing factor in pituitary apoplexy (PA). Utilizing one of the largest cohorts in the literature, this study aims to determine the risk of PA in patients on antiplatelet/anticoagulation (AP/AC) therapy. Methods A single center, retrospective study was conducted on 342 pituitary adenoma patients, of which 77 patients presented with PA (23%). Several potential risk factors for PA were assessed, including: patient demographics, tumor characteristics, pre-operative hormone replacement, neurologic deficits, coagulation studies, platelet count, and AP/AC therapy. Results Comparing patients with and without apoplexy, there was no significant difference in the proportion of patients taking aspirin (45 no apoplexy vs. 10 apoplexy; p = 0.5), clopidogrel (10 no apoplexy vs. 4 apoplexy; p = 0.5), and anticoagulation (7 no apoplexy vs. 3 apoplexy; p = 0.7). However, male sex (p-value < 0.001) was a predictor for apoplexy while pre-operative hormone treatment was a protective factor from apoplexy (p-value < 0.001). A non-clinical difference in INR was also noted as a predictor for apoplexy (no apoplexy: 1.01 ± 0.09, apoplexy: 1.07 ± 0.15; p < 0.001). Conclusions Although pituitary tumors have a high risk for spontaneous hemorrhage, the use of aspirin is not a risk for hemorrhage. Our study did not find an increased risk of apoplexy with clopidogrel or anticoagulation, but further investigation is needed with a larger cohort. Confirming other reports, male sex is associated with an increased risk for PA.

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating form of stroke frequently affecting young to middle-aged adults, with an unmet need to improve outcome. This special report focusses on the development of intrathecal haptoglobin supplementation as a treatment by reviewing current knowledge and progress, arriving at a Delphi-based global consensus regarding the pathophysiological role of extracellular hemoglobin and research priorities for clinical translation of hemoglobin-scavenging therapeutics. After aneurysmal subarachnoid hemorrhage, erythrocyte lysis generates cell-free hemoglobin in the cerebrospinal fluid, which is a strong determinant of secondary brain injury and long-term clinical outcome. Haptoglobin is the body’s first-line defense against cell-free hemoglobin by binding it irreversibly, preventing translocation of hemoglobin into the brain parenchyma and nitric oxide-sensitive functional compartments of cerebral arteries. In mouse and sheep models, intraventricular administration of haptoglobin reversed hemoglobin-induced clinical, histological, and biochemical features of human aneurysmal subarachnoid hemorrhage. Clinical translation of this strategy imposes unique challenges set by the novel mode of action and the anticipated need for intrathecal drug administration, necessitating early input from stakeholders. Practising clinicians (n=72) and scientific experts (n=28) from 5 continents participated in the Delphi study. Inflammation, microvascular spasm, initial intracranial pressure increase, and disruption of nitric oxide signaling were deemed the most important pathophysiological pathways determining outcome. Cell-free hemoglobin was thought to play an important role mostly in pathways related to iron toxicity, oxidative stress, nitric oxide, and inflammation. While useful, there was consensus that further preclinical work was not a priority, with most believing the field was ready for an early phase trial. The highest research priorities were related to confirming haptoglobin’s anticipated safety, individualized versus standard dosing, timing of treatment, pharmacokinetics, pharmacodynamics, and outcome measure selection. These results highlight the need for early phase trials of intracranial haptoglobin for aneurysmal subarachnoid hemorrhage, and the value of early input from clinical disciplines on a global scale during the early stages of clinical translation.

The blood-brain barrier (BBB) controls the movement of molecules into and out of the central nervous system (CNS). Since a functional BBB forms by mouse embryonic day E15.5, we reasoned that gene cohorts expressed in CNS endothelial cells (EC) at E13.5 contribute to BBB formation, whereas adult gene signatures reflect BBB maintenance mechanisms. Supporting this hypothesis, transcriptomic analysis revealed distinct cohorts of EC genes during BBB formation and maintenance. Here we demonstrate that epigenetic regulator’s histone deacetylase 2 (HDAC2) and polycomb repressive complex 2 (PRC2) control EC gene expression for BBB development and prevented Wnt/β-catenin (Wnt) target genes from being expressed in adult CNS ECs. Low Wnt activity during development modifies BBB genes epigenetically for the formation of functional BBB. As a Class-I HDAC inhibitor induces adult CNS ECs to regain Wnt activity and BBB genetic signatures that support BBB formation, our results inform strategies to promote BBB repair.

Brain vascular staining is very important for understanding cerebrovascular pathologies. 4% paraformaldehyde is considered the gold standard fixation technique for immunohistochemistry and it revolutionized the examination of proteins in fixed tissues. However, this fixation technique produces inconsistent immunohistochemical staining results due to antigen masking. Here, we test a new fixation protocol using 3% glyoxal and demonstrate that this method improves the staining of the brain vasculature, pericytes, and tight junction proteins compared to 4% paraformaldehyde. Use of this new fixation technique will provide more detailed information about vascular protein expressions, their distributions, and colocalizations with other proteins at the molecular level in the brain vasculature.

Brain vascular staining has great importance in understanding cerebrovascular pathologies. 4% Paraformaldehyde is considered as the gold standard fixation technique for immunohistochemistry and it revolutionized the examination of proteins in fixed tissues. However, this fixation technique produces inconsistent immunohistochemical staining results due to antigen masking. Here we test a new fixation protocol using 3% glyoxal and demonstrate that this method improves staining of the brain vasculature, pericytes, and tight junction proteins compared to 4% paraformaldehyde. Using this new fixation technique will provide more detailed information about vascular protein expressions, their distributions, and colocalizations with other proteins at the molecular level in the brain vasculature.

Brain vascular staining has great importance in understanding cerebrovascular pathologies. Paraformaldehyde 4% is considered the gold standard fixation technique for immunohistochemistry and it revolutionized the examination of proteins in fixed tissues. However, this fixation technique produces inconsistent immunohistochemical staining results due to antigen masking. Here we test a new fixation protocol using 3% glyoxal and demonstrate that this method provides overall better staining of the brain vasculature, pericytes, and tight junction proteins than 4% paraformaldehyde. Using this new fixation technique will provide more detailed information about vascular protein expressions, their distributions, and colocalizations with other proteins at the molecular level in the brain vasculature.

Objective This study was undertaken to evaluate functional and safety outcomes for endovascular thrombectomy (EVT) versus medical management (MM) in patients with large vessel occlusion (LVO) and mild neurological deficits, stratified by perfusion imaging mismatch. Methods The pooled cohort consisted of patients with National Institutes of Health Stroke Scale (NIHSS) < 6 and internal carotid artery (ICA), M1, or M2 occlusions from the Extending the Time for Thrombolysis in Emergecy Neurological Deficits - Intra-Arterial (EXTEND-IA) Trial, Tenecteplase vs Alteplase before Endovascular Thrombectomy in Ischemic Stroke (EXTEND-IA TNK) trials Part I/II and prospective data from 15 EVT centers from October 2010 to April 2020. RAPID software estimated ischemic core and mismatch. Patients receiving primary EVT (EVTpri) were compared to those who received primary MM (MMpri), including those who deteriorated and received rescue EVT, in overall and propensity score (PS)-matched cohorts. Patients were stratified by target mismatch (mismatch ratio >= 1.8 and mismatch volume >= 15ml). Primary outcome was functional independence (90-day modified Rankin Scale = 0-2). Secondary outcomes included safety (symptomatic intracerebral hemorrhage [sICH], neurological worsening, and mortality). Results Of 540 patients, 286 (53%) received EVTpri and demonstrated larger critically hypoperfused tissue (Tmax > 6 seconds) volumes (median [IQR]: 64 [26-96] ml vs MMpri: 40 [14-76] ml, p < 0.001) and higher presentation NIHSS (median [IQR]: 4 [2-5] vs MMpri: 3 [2-4], p < 0.001). Functional independence was similar (EVTpri: 77.4% vs MMpri: 75.6%, adjusted odds ratio [aOR] = 1.29, 95% confidence interval [CI] = 0.82-2.03, p = 0.27). EVT had worse safety regarding sICH (EVTpri: 16.3% vs MMpri: 1.3%, p < 0.001) and neurological worsening (EVTpri: 19.6% vs MMpri: 6.7%, p < 0.001). In 414 subjects (76.7%) with target mismatch, EVT was associated with improved functional independence (EVTpri: 77.4% vs MMpri: 72.7%, aOR = 1.68, 95% CI = 1.01-2.81, p = 0.048), whereas there was a trend toward less favorable outcomes with primary EVT (EVTpri: 77.4% vs MMpri: 83.3%, aOR = 0.39, 95% CI = 0.12-1.34, p = 0.13) without target mismatch (p(interaction) = 0.06). Similar findings were observed in a propensity score-matched subpopulation. Interpretation Overall, EVT was not associated with improved clinical outcomes in mild strokes due to LVO, and sICH was increased. However, in patients with target mismatch profile, EVT was associated with increased functional independence. Perfusion imaging may be helpful to select mild stroke patients for EVT. ANN NEUROL 2022

Aneurysmal subarachnoid hemorrhage (aSAH) causes a robust inflammatory response which leads worse brain injury and poor outcomes. We investigated if stimulation of nicotinic acetylcholine α(7) receptors (α(7)-AChR) (receptors shown to have anti-inflammatory effects) would reduce inflammation and improve outcomes. To investigate the level of peripheral inflammation after aSAH, inflammatory markers were measured in plasma samples collected in a cohort of aSAH patients. To study the effect of α(7)-AChR stimulation, SAH was induced in adult mice which were then treated with a α(7)-AChR agonist, galantamine, or vehicle. A battery of motor and cognitive tests were performed 24 h after subarachnoid hemorrhage. Mice were euthanized and tissue collected for analysis of markers of inflammation or activation of α(7)-AChR-mediated transduction cascades. A separate cohort of mice was allowed to survive for 28 days to assess long-term neurological deficits and histological outcome. Microglia cell culture subjected to hemoglobin toxicity was used to assess the effects of α(7)-AChR agonism. Analysis of eighty-two patient plasma samples confirmed enhanced systemic inflammation after aSAH. α(7)-AChR agonism reduced neuroinflammation at 24 h after SAH in male and female mice, which was associated with improved outcomes. This coincided with JAK2/STAT3 and IRAK-M activity modulations and a robust improvement in neurological/cognitive status that was effectively reversed by interfering with various components of these signaling pathways. Pharmacologic inhibition partially reversed the α(7)-AChR agonist’s benefits, supporting α(7)-AChR as a target of the agonist’s therapeutic effect. The cell culture experiment showed that α(7)-AChR agonism is directly beneficial to microglia. Our results demonstrate that activation of α(7)-AChR represents an attractive target for treatment of SAH. Our findings suggest that α(7)-AChR agonists, and specifically galantamine, might provide therapeutic benefit to aSAH patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13311-021-01052-3.

Bilirubin is a primary product of heme catabolism and exhibits both neuroprotective and neurotoxic effects. When present at physiologic concentrations, bilirubin is a potent antioxidant and serves to protect brain tissue from oxidative stress insults. The use of the anesthetic propofol attenuates ischemic injury in rats by exploiting these neuroprotective properties. At pathologic levels, bilirubin has been implicated as a neurotoxic agent, demonstrating the ability to aggregate and adhere to cellular membranes, thereby disrupting normal cellular function. Bilirubin-associated toxicities are amplified by administering drugs such as anesthetics that compete with bilirubin for albumin binding sites, resulting in increased plasma bilirubin concentrations. As such, it is crucial that bilirubin is considered in the critical care management of patients with hemorrhagic stroke, cerebral ischemic damage, and critically ill newborns.

Delayed cerebral ischemia (DCI) is a major determinant of patient outcome following aneurysmal subarachnoid hemorrhage. Although the exact mechanisms leading to DCI are not fully known, inflammation, cerebral vasospasm, and microthrombi may all function together to mediate the onset of DCI. Indeed, inflammation is tightly linked with activation of coagulation and microthrombi formation. Thromboinflammation is the intersection at which inflammation and thrombosis regulate one another in a feedforward manner, potentiating the formation of thrombi and pro-inflammatory signaling. In this review, we will explore the role(s) of inflammation and microthrombi in subarachnoid hemorrhage (SAH) pathophysiology and DCI, and discuss the potential of targeting thromboinflammation to prevent DCI after SAH.

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a benign variant of SAH defined by clinical symptoms of SAH, a characteristic pattern of extravasated blood on noncontrast CT, and negative findings on cerebral angiography. This syndrome carries a favorable prognosis with reportedly no risk of recurrent hemorrhage. The authors present the case of a 62-year-old man with no significant medical history who experienced recurrent, spontaneous episodes of PNSAH within the course of 5 months. No precipitating causes were identified, but the patient had been involved in exertional activities preceding both events. To the authors' knowledge, this is the first conclusive report of recurrent, idiopathic PNSAH. The findings suggest that while the risk of recurrent hemorrhage in the setting of PNSAH is far less than that for aneurysmal SAH, rebleeding can still occur. The authors speculate on the etiology of this rare phenomenon.

Large cerebral arteriovenous malformations (AVMs) are often not amenable to direct resection or stereotactic radiosurgery (SRS) treatment. An alternative treatment strategy is staged endovascular embolization followed by SRS (Embo/SRS). The object of this study was to examine the experience at Washington University in St. Louis with Embo/SRS for large AVMs and review the results in earlier case series.Twenty-one cases involving patients with large AVMs treated with Embo/SRS between 1994 and 2006 were retrospectively evaluated. The AVM size (before and after embolization), procedural complications, radiological outcome, and neurological outcome were examined. Radiological success was defined as AVM obliteration as demonstrated by catheter angiography, CT angiography, or MR angiography. Radiological failure was defined as residual AVM as demonstrated by catheter angiography, CT angiography, or MR angiography performed at least 3 years after SRS.The maximum diameter of all AVMs in this series was3 cm (mean 4.2 cm); 12 (57%) were Spetzler-Martin Grade IV or V. Clinical follow-up was available in 20 of 21 cases; radiological follow-up was available in 19 of 21 cases (mean duration of follow-up 3.6 years). Forty-three embolization procedures were performed; 8 embolization-related complications occurred, leading to transient neurological deficits in 5 patients (24%), minor permanent neurological deficits in 3 patients (14%), and major permanent neurological deficits in none (0%). Twenty-one SRS procedures were performed; 1 radiation-induced complication occurred (5%), leading to a permanent minor neurological deficit. Of the 20 patients with clinical follow-up, none experienced cerebral hemorrhage. In the 19 patients with radiological follow-up, AVM obliteration was confirmed by catheter angiography in 13, MR angiography in 2, and CT angiography in 1. Residual nidus was found in 3 patients. In patients with follow-up catheter angiography, the AVM obliteration rate was 81% (13 of 16 cases).Staged endovascular embolization followed by SRS provides an effective means of treating large AVMs not amenable to standard surgical or SRS treatment. The outcomes and complication rates reported in this series compare favorably to the results of other reported therapeutic strategies for this very challenging patient population.

The aim of this study was to determine the efficacy of venous ultrasonography in screening for deep venous thrombosis (DVT) after subarachnoid hemorrhage (SAH). A large cohort of patients who had suffered SAH was evaluated with the primary end points of ascertaining the incidence of asymptomatic DVT with venous Doppler ultrasonography screening and of identifying risk factors for the development of DVT and subsequent pulmonary embolism.Data from patients with aneurysmal SAH who had been admitted to the neurosurgical intensive care unit (ICU) between December 2002 and October 2006 were retrospectively evaluated. Patients who had undergone surgical or endovascular treatment of an aneurysm following SAH and survivedor = 15 days were included in the study.The overall incidence of DVT among the entire study cohort was 18%. A subgroup analysis identified all patients, with or without symptoms for DVT, who had undergone venous Doppler ultrasonography screening. The incidence of asymptomatic DVT was 24%. Univariate analysis of all patients revealed a significant correlation between the risk of DVT and Hunt and Hess grade (r = 0.38, p0.0001), Fisher grade (r = 0.31, p0.0001), total hospital stay (r = 0.49, p0.0001), and number of days in the ICU (r = 0.48, p0.0001). Multivariate analysis demonstrated that the total hospital stay and number of days in the ICU were significant predictors of DVT in all patients (p0.0001 and p0.0002, respectively). In the subgroup of screened patients, Hunt and Hess grade, total hospital stay, and number of days in the ICU were significant predictors of DVT. Although screened patients were more likely to have DVT (chi(2) = 6.0976, p0.02), there was no significant difference in the incidence of DVT or pulmonary embolism between patients who did and those who did not undergo routine lower-extremity Doppler ultrasonography screening.Routine compressive venous Doppler ultrasonography is an efficient, noninvasive means of identifying DVT as a screening modality in both symptomatic and asymptomatic patients following aneurysmal SAH. The ability to confirm or deny the presence of DVT in this patient population allows one to better identify the indications for chemoprophylaxis. Prophylaxis for venous thromboembolism in neurosurgical patients is common. Emerging literature and anecdotal experience have exposed risks of complications with prophylactic anticoagulation protocols. The identification of patients at high risk-for example, those with asymptomatic DVT-will allow physicians to better assess the role of prophylactic anticoagulation.

The authors report on an 8-month-old infant with an orbital capillary hemangioma. The patient had been treated with high-dose corticosteroid therapy and had had a recent decrease in dose. The patient presented to the emergency department with increased irritability and bulging fontanelles. On lumbar puncture the opening pressure was55 cm H(2)O. Ophthalmological examination revealed interval development of papilledema. The child was treated with high-volume lumbar puncture, subsequent drainage of 10 ml of cerebrospinal fluid, resumption of the previous steroid dose, and acetazolomide therapy. The patient's symptoms resolved and follow-up ophthalmological examination revealed interval resolution of papilledema. The authors present the youngest reported case of pseudotumor development after corticosteroid tapering.

Candidate gene studies have identified genetic variants associated with clinical outcomes following aneurysmal subarachnoid haemorrhage (aSAH), but no genome-wide association studies have been performed to date. Here we report the results of the discovery phase of a two-stage genome-wide meta-analysis of outcome after aSAH. We identified 157 independent loci harbouring 756 genetic variants associated with outcome after aSAH (p −4), which require validation. A single variant (rs12949158), in SPNS2, achieved genome-wide significance (p = 4.29 × 10−8) implicating sphingosine-1-phosphate signalling in outcome after aSAH. A large multicentre international effort to recruit samples for validation is required and ongoing. Validation of these findings will provide significant insight into the pathophysiology of outcomes after aSAH with potential implications for treatment.