Search

Abstract Background M1 and M2 cells are two major subsets of human macrophages that exert opposite effects on the inflammatory response. This study aims to investigate the role of macrophage M1/M2 imbalance and mast cells in the progression of human cerebral aneurysms to rupture. Methods Ten patients with cerebral aneurysms (five ruptured and five unruptured) underwent microsurgical clipping. During the procedure, a segment of the aneurysm dome was resected and immunostained with monoclonal antibodies for M1 cells (anti-HLA DR), M2 cells (anti-CD 163), and mast cells (anti-tryptase clone AA). A segment of the superficial temporal artery (STA) was also removed and immunostained with monoclonal antibodies for M1, M2, and mast cells. Results All ten aneurysm tissues stained positive for M1, M2, and mast cells. M1 and M2 cells were present in equal proportions in unruptured aneurysms. This contrasted with a marked predominance of M1 over M2 cells in ruptured aneurysms (p = 0.045). Mast cells were also prominently upregulated in ruptured aneurysms (p = 0.001). Few M1 and M2 cells were present in STA samples. Conclusions M1/M2 macrophages and mast cells are found in human cerebral aneurysms; however, M1 and mast cell expression seems to markedly increase in ruptured aneurysms. These findings suggest that macrophage M1/M2 imbalance and upregulation of mast cells may have a role in the progression of cerebral aneurysms to rupture.

(1) Background: Neuroendovascular procedures have generally been considered to have minor or inconsequential blood loss. No study, however, has investigated this question. The purpose of this study is to quantify the blood loss associated with neuroendovascular procedures and identify predictors of blood loss, using hemoglobin change as a surrogate for blood loss. (2) Methods: A retrospective review of 200 consecutive endovascular procedures (diagnostic and therapeutic) at our institution from January 2020 to October 2020 was performed. Patients had to have pre- and post-operative hematocrit and hemoglobin levels recorded within 48 h of the procedure (with no intervening surgeries) for inclusion. (3) Results: The mean age of our cohort was 60.1 years and the male representation was 52.5%. The mean pre-operative hemoglobin/hematocrit was significantly lower among females compared to males (12.1/36.2 vs. 13.0/38.5, p = 0.003, p = 0.009). The mean hemoglobin decrease was 0.5 g/dL for diagnostic angiograms compared to 1.2 g/dL for endovascular interventions ( p < 0.0001), and 1.0 g/dL for all procedures combined. In a multivariate linear regression analysis, pre-operative antiplatelet/anticoagulant use was associated with a statistically significant decrease in hemoglobin. (4) Conclusions: Our data support that blood loss from diagnostic angiograms is marginal. Blood loss in endovascular interventions, however, tends to be higher. Pre-operative blood antiplatelet/anticoagulant use and increasing age appear to increase bleeding risk and may require closer patient monitoring.

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., Competing Interests: Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision.

Objective: Telemedicine encounters are expanding in utility for outpatient care and evaluation, partially as a necessity during the COVID-19 pandemic. It is unclear if telemedicine evaluation is comparable to in-person assessment of patients with spinal pathology undergoing surgical consultation. The objective of this study was to determine if treatment plans change for spine patients evaluated in person following an initial telemedicine consultation., Methods: Patients referred to the authors' comprehensive spine center were evaluated first via telemedicine and then in clinic. Telemedicine evaluations were conducted via video evaluation with an attending surgeon. Demographic data including age, gender, and distance traveled from the clinic were retrospectively recorded. A chart review retrieved symptoms, radiographic details, and past medical history. The primary outcome was if the treatment plan changed (plan change [PC]) after seeing the patient in the clinic. Chi-square tests and binary logistical regression produced uni- and multivariate analyses., Results: There were 152 new patients seen via telemedicine and in person. Pathology was present in the cervical (28.3%), thoracic (9.9%), and lumbar (61.8%) spine. The most common symptom was pain (72.4%), followed by radiculopathy (66.4%), weakness (26.3%), myelopathy (15.1%), and claudication (12.5%). There were 37 patients (24.3%) for whom there was a PC after clinic evaluation, and of those, only 5 (3.3%) were due to physical examination (PCPE) findings. On univariate analysis, a longer duration between telemedicine and clinic visit (odds ratio [OR] 1.094 per 7 days, p = 0.003), having pathology in the thoracic spine (OR 3.963, p = 0.018) and lack of sufficient imaging (OR 25.455, p < 0.0001) were predictive of a PC. Having pathology in the cervical spine (OR 9.538, p = 0.047) and adjacent-segment disease (OR 11.471, p = 0.010) were predictive of a PCPE., Conclusions: This study demonstrates that telemedicine may be an effective modality for the initial evaluation of spine surgical patients, without compromising decision-making in the absence of an in-person physical examination.

Introduction: National and international trends continue to show greater emphasis on endovascular techniques for the treatment of cerebrovascular disease. The cerebrovascular neurosurgeon however must be adequately equipped to treat these patients via both open and endovascular techniques., Methods: The decline in open cerebrovascular cases for aneurysm clipping has forced many trainees to pursue open cerebrovascular fellowships to increase case volume. An alternative strategy has been employed at our institution, which is early identification of subspecialty focus with resident driven self-selection of open cerebrovascular cases., Results: This has allowed recent graduates to obtain enfolded endovascular training and a significant number of open cerebrovascular cases in order to obtain competence and exposure., Discussion: We advocate for further self-selection paradigms supplemented with simulation training in order to obviate the need for extended post-residency fellowships., (Copyright © 2022 Sociedad Española de Neurocirugía. All rights reserved.)

Background: Cerebral vasospasm (CV) can contribute to significant morbidity in subarachnoid hemorrhage (SAH) patients. A key unknown is how CV induction is triggered following SAH., Methods: Human aneurysmal blood and cerebral spinal fluid were collected for evaluation. To confirm mechanism, c57/bl6 wild type and c57/bl6 IL-6 female knockout (KO) mice were utilized with groups: saline injected, SAH, SAH + IL-6 blockade, SAH IL-6 KO, SAH IL-6 KO + IL-6 administration, SAH + p-STAT3 inhibition. Dual-labeled microglia/myeloid mice were used to show myeloid diapedesis. For SAH, 50 μm blood was collected from tail puncture and administered into basal cisterns. IL-6 blockade was given at various time points. Various markers of neuroinflammation were measured with western blot and immunohistochemistry. Cerebral blood flow was also measured. Vasospasm was measured via cardiac injection of India ink/gelatin. Turning test and Garcia's modified SAH score were utilized. P < 0.05 was considered significant., Results: IL-6 expression peaked 3 days following SAH (p < 0.05). Human IL-6 was increased in aneurysmal blood (p < 0.05) and in cerebral spinal fluid (p < 0.01). Receptor upregulation was periventricular and perivascular. Microglia activation following SAH resulted in increased caveolin 3 and myeloid diapedesis. A significant increase in BBB markers endothelin 1 and occludin was noted following SAH, but reduced with IL-6 blockade (p < 0.01). CV occurred 5 days post-SAH, but was absent in IL-6 KO mice and mitigated with IL-6 blockade (p < 0.05). IL-6 blockade, and IL-6 KO mitigated effects of SAH on cerebral blood flow (p < 0.05). SAH mice had impaired performance on turn test and poor modified Garcia scores compared to saline and IL-6 blockade. A distinct microglia phenotype was noted day 5 in the SAH group (overlap coefficients r = 0.96 and r = 0.94) for Arg1 and iNOS, which was altered by IL-6 blockade. Day 7, a significant increase in toll-like receptor 4 and Stat3 was noted. This was mitigated by IL-6 blockade and IL-6 KO, which also reduced Caspase 3 (p < 0.05). To confirm the mechanism, we developed a p-STAT3 inhibitor that targets the IL-6 pathway and this reduced NFΚB, TLR4, and nitrotyrosine (p < 0.001). Ventricular dilation and increased Tunel positivity was noted day 9, but resolved by IL-6 blockade (p < 0.05)., Conclusion: Correlation between IL-6 and CV has been well documented. We show that a mechanistic connection exists via the p-STAT3 pathway, and IL-6 blockade provides benefit in reducing CV and its consequences mediated by myeloid cell origin diapedesis., (© 2022. The Author(s).)

Background and Objective: Rapid reperfusion of ischemic penumbra in patients with acute stroke is critical to neurological recovery. Achieving reperfusion after first-pass mechanical thrombectomy has been associated with improved patient outcomes. However, the predictors for obtaining first-pass reperfusion are not well known., Methods: A single-institution retrospective study of all patients who underwent mechanical thrombectomy at a tertiary care center from January 2010 until March 2019 was conducted to assess for predictors of first-pass reperfusion., Results: A total of 257 patients were reviewed. Successful reperfusion was obtained in 63.4% of patients, and in 38% of patients on the first pass. On multivariate analysis, increasing door-to-puncture time was a negative predictor of FPR (OR 0.989, 95% CI = 0.980-0.997) and use of combined thrombectomy technique with stent-retriever and aspiration was a positive predictor of FPR compared to aspiration or stent-retriever alone (OR 4.441, 95% CI = 1.001-19.699)., Conclusions: Combination therapy using stent-retriever and aspiration may increase the chance of obtaining FPR, whereas delays in starting the procedure after patient arrival may decrease the odds of FPR. Rapid thrombectomy initiation and procedural technique may play in optimizing rates of FPR and ultimately patient outcomes, however, randomized controlled trials assessing these variables are necessary to determine optimal treatment strategies., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The history of cerebral aneurysm treatment has a rich and storied past with multiple notable luminaries contributing insights. The modern era has transitioned from primarily clip ligation to increasing use of endovascular therapy. Even more recently, the use of intrasaccular flow diverters has been introduced for the treatment of wide necked aneurysms. The field is continuing to transform, and bioactive coils and stents have resurfaced as promising adjuvants to promote aneurysm healing. Advanced imaging modalities are being developed that could further advance the endovascular arsenal and allow for porous memory polymer devices to enter the field. This focused review highlights notable historic contributions and advances to the point of futuristic technology that is actively being developed., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

Delayed cerebral ischemia (DCI) contributes to extensive morbidity and mortality for patients with aneurysmal subarachnoid hemorrhage (SAH). Recent contributions to the basic and translational investigation of DCI have shed light on emerging concepts that may aid in the development of novel therapeutics. A clear association between cerebral vasospasm (CV) and DCI exists, but it is also known that DCI can affect brain parenchyma remote from sites of vasospasm. In this review, we highlight the most recent contributions to the understanding of the underlying pathophysiology of DCI including the emerging role of the glymphatic system. Furthermore, we discuss treatments for DCI, including both pharmacologic therapies and endovascular treatment of vasospasm. There continues to be a disconnect between interventions and targeted treatment against pathophysiology. This review is intended to serve as a catalyst for further research and discovery that can aid in improved treatment options for DCI., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The Woven EndoBridge (WEB) device is becoming increasingly popular for treatment of wide-neck aneurysms. As experience with this device grows, it is important to identify factors associated with occlusion following WEB treatment to guide decision making and screen patients at high risk for recurrence. The aim of this study was to identify factors associated with adequate aneurysm occlusion following WEB device treatment in the neurosurgical literature and in our case series. A systematic review of the present literature was conducted to identify studies related to the prediction of WEB device occlusion. In addition, a retrospective review of our institutional data for patients treated with the WEB device was performed. Demographics, aneurysm characteristics, procedural variables, and 6-month follow-up angiographic outcomes were recorded. Seven articles totaling 450 patients with 456 aneurysms fit our criteria. Factors in the literature associated with inadequate occlusion included larger size, increased neck width, partial intrasaccular thrombosis, irregular shape, and tobacco use. Our retrospective review identified 43 patients with 45 aneurysms. A total of 91.1% of our patients achieved adequate occlusion at a mean follow-up time of 7.32 months. Increasing degree of contrast stasis after WEB placement on the post-deployment angiogram was significantly associated with adequate occlusion on follow-up angiogram (p = 0.005) and with Raymond-Roy classification (p = 0.048), but not with retreatment (p = 0.617). In our systematic review and case series totaling 450 patients with 456 aneurysms, contrast stasis on post-deployment angiogram was identified as a predictor of adequate aneurysm occlusion, while morphological characteristics such as larger size and wide neck negatively impact occlusion., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: To date, limited studies have been conducted regarding the safe timing of valvular repair for infectious endocarditis (IE) in patients with radiographic findings consistent with embolic stroke or infectious intracranial aneurysm (IIA)., Methods: A single-center, retrospective review of valvular surgeries for IE was performed (2011-2019). Outcomes for patients who underwent cranial image screening and those who did not were subsequently compared., Results: 276 patients underwent valvular repair for IE; 186 (67.4%) were male. The mean age was 51.0 (17.4) years. Mean time from imaging to surgery was 7.5 days. 124 (44.9%) underwent baseline cranial imaging. Of these, 22 (17.7%) had findings concerning for ischemic stroke from embolic origin. 65 patients underwent baseline diagnostic cerebral angiography. 10 (15%) of these patients harbored an IIA. Four out of these 10 (40%) underwent intervention for an IIA. Two of the four who underwent intervention (50.0%) had ruptured IIAs. The remaining six (60%) patients with IIAs received treatment with antibiotics alone. None of the patients with IIAs suffered from symptomatic hemorrhage after valvular surgery. No significant difference in symptomatic hemorrhage after valvular surgery between those with ischemic embolic stroke compared to those without (ischemic stroke-4.5% vs. no ischemic stroke-1.0%; p = 0.32)., Conclusions: Patients with radiographic evidence of ischemic stroke from septic emboli can safely undergo valvular surgery for IE without increased risk of symptomatic hemorrhage. We advocate for baseline CTA screening to evaluate for IIA in patients who present with a primary diagnosis of IE and propose a management algorithm., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The placement of cervical and intracranial stents requires the administration of antiplatelet drugs to prevent thromboembolic complications. Ticagrelor has emerged as the most widely used alternative in clopidogrel non-responders owing to its potent antiplatelet effects. Because ticagrelor does not require hepatic activation, many neurointerventionalists choose to forgo laboratory testing of platelet inhibition. In rare instances, patients may not achieve adequate platelet inhibition following ticagrelor administration. In this paper we review the mechanism of action of ticagrelor and its use in cerebrovascular procedures. We present two cases of ticagrelor non-responsiveness from two high-volume cerebrovascular centers, discuss their management, and propose an algorithm for managing ticagrelor non-responsiveness., Competing Interests: Competing interests: BH is a lead investigator of the CAPTIVA RCT trial. AstraZeneca is supporting the CAPTIVA trial by providing ticagrelor (https://www.nihstrokenet.org/docs/default-source/default-document-library/hoh-captiva-9-12-18-v3ef07f0d0c2c66f0f86baff000016a715.pdf?sfvrsn=0)., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

The genetics of intracranial aneurysms is complex. Much work has been done looking at the extracellular matrix surrounding cerebral vasculature as well as the role of matrix metalloproteinases. This comprehensive review summarizes what is known to date about the important genetic components that predispose to aneurysm formation and critically discusses the published findings. We discuss promising pre-clinical models of aneurysm formation and subarachnoid hemorrhage, and highlight avenues for future discovery, while considering limitations in the research to date. This review will further serve as a comprehensive reference guide to understand the genetic underpinnings for aneurysm pathophysiology and act as a primer for further investigation., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Cell-free heme-containing proteins mediate endothelial injury in a variety of disease states including subarachnoid hemorrhage and sepsis by increasing endothelial permeability. Inflammatory cells are also attracted to sites of vascular injury by monocyte chemotactic protein 1 (MCP-1) and other chemokines. We have identified a novel peptide hormone, adropin, that protects against hemoglobin-induced endothelial permeability and MCP-1-induced macrophage migration., Methods: Human microvascular endothelial cells were exposed to cell-free hemoglobin (CFH) with and without adropin treatment before measuring monolayer permeability using a FITC-dextran tracer assay. mRNA and culture media were collected for molecular studies. We also assessed the effect of adropin on macrophage movement across the endothelial monolayer using an MCP-1-induced migration assay., Results: CFH exposure decreases adropin expression and increases paracellular permeability of human endothelial cells. Treating cells with synthetic adropin protects against the increased permeability observed during the natural injury progression. Cell viability was similar in all groups and Hmox1 expression was not affected by adropin treatment. MCP-1 potently induced macrophage migration across the endothelial monolayer and adropin treatment effectively reduced this phenomenon., Conclusions: Endothelial injury is a hallmark of many disease states. Our results suggest that adropin treatment could be a valuable strategy in preventing heme-mediated endothelial injury and macrophage infiltration. Further investigation of adropin therapy in animal models and human tissue specimens is needed., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Brian L. Hoh reports financial support was provided by National Institutes of Health. William S. Dodd & Brian L. Hoh reports financial support was provided by The Brain Aneurysm Foundation., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Wide-neck bifurcation cerebral aneurysms have historically required either clip ligation or stent- or balloon-assisted coil embolization. This predicament led to the development of the Woven EndoBridge (WEB) aneurysm embolization system, a self-expanding mesh device that achieves intrasaccular flow disruption and does not require antithrombotic medications. The authors report their operative experience and 6-month follow-up occlusion outcomes with the first 115 aneurysms they treated via WEB embolization., Methods: The authors reviewed the first 115 cerebral aneurysms they treated by WEB embolization after FDA approval of the WEB embolization device (from February 2019 to January 2021). Data were collected on patient demographics and clinical presentation, aneurysm characteristics, procedural details, postembolization angiographic contrast stasis, and functional outcomes., Results: A total of 110 patients and 115 aneurysms were included in our study (34 ruptured and 81 unruptured aneurysms). WEB embolization was successful in 106 (92.2%) aneurysms, with a complication occurring in 6 (5.5%) patients. Contrast clearance was seen in the arterial phase in 14 (12.2%) aneurysms, in the capillary phase in 16 (13.9%), in the venous phase in 63 (54.8%), and no contrast was seen in 13 (11.3%) of the aneurysms studied. Follow-up angiography was performed on 60 (52.6%) of the aneurysms, with complete occlusion in 38 (63.3%), neck remnant in 14 (23.3%), and aneurysmal remnant in 8 (13.3%). Six (5.5%) patients required re-treatment for persistent aneurysmal residual on follow-up angiography., Conclusions: The WEB device has been successfully used for the treatment of both unruptured and ruptured wide-neck bifurcation aneurysms by achieving intrasaccular flow diversion. Here, the authors have shared their experience with its unique technical considerations and device size selection, as well as critically reviewed complications and aneurysm occlusion rates.

Objective: Postoperative urinary retention (POUR) is a common complication after spine surgery and is associated with prolongation of hospital stay, increased hospital cost, increased rate of urinary tract infection, bladder overdistention, and autonomic dysregulation. POUR incidence following spine surgery ranges between 5.6% and 38%; no reliable prediction tool to identify those at higher risk is available, and that constitutes an important gap in the literature. The objective of this study was to develop and validate a preoperative risk model to predict the occurrence of POUR following routine elective spine surgery., Methods: The authors conducted a retrospective chart review of consecutive adults who underwent lumbar spine surgery between June 1, 2017, and June 1, 2019. Patient characteristics, preexisting ICD-10 codes, preoperative pain and opioid use, preoperative alpha-1 blocker use, details of surgical planning, development of POUR, and management strategies were abstracted from electronic medical records. A binomial logistic model and a multilayer perceptron (MLP) were optimized using training and validation sets. The models' performance was then evaluated on model-naïve patients (not a part of either cohort). The models were then stacked to take advantage of each model's strengths and to avoid their weaknesses. Four additional models were developed from previously published models adjusted to include only relevant factors (i.e., factors known preoperatively and applied to the lumbar spine)., Results: Overall, 891 patients were included in the cohort, with a mean of 59.6 ± 15.5 years of age, 52.7% male, BMI 30.4 ± 6.4, American Society of Anesthesiologists class 2.8 ± 0.6, and a mean of 5.6 ± 5.7 comorbidities. The rate of POUR was found to be 25.9%. The two models were comparable, with an area under the curve (AUC) of 0.737 for the regression model and 0.735 for the neural network. By combining the two models, an AUC of 0.753 was achieved. With a regression model probability cutoff of 0.24 and a neural network cutoff of 0.23, maximal sensitivity and specificity were achieved, with specificity 68.2%, sensitivity 72.9%, negative predictive value 88.2%, and positive predictive value 43.4%. Both models individually outperformed previously published models (AUC 0.516-0.645) when applied to the current data set., Conclusions: This predictive model can be a powerful preoperative tool in predicting patients who will be likely to develop POUR. By using a combination of regression and neural network modeling, good sensitivity, specificity, and NPV are achieved.

Objective: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is a pressing public health issue. Although most cases do not result in severe illness requiring hospitalization, there is increasing evidence that SARS-CoV-2-induced inflammation can exacerbate pre-existing diseases. We sought to describe the characteristics of patients with aneurysmal subarachnoid hemorrhage who were actively or very recently infected with SARS-CoV-2., Methods: We reviewed subarachnoid hemorrhage cases of patients who also were positive for SARS-CoV-2 at 5 high-volume cerebrovascular centers in the United States from March 2020 to January 2021. Cases of aneurysmal subarachnoid hemorrhage were analyzed., Results: A total of 10 patients were identified, consisting of 5 women (50%) and 5 men (50%). Median age was 38.5 years. Four of the 10 patients (40%) were asymptomatic with respect to SARS-CoV-2-related symptoms, 3 patients (30%) had mild-to-moderate symptoms, and 3 patients (30%) had severe coronavirus disease 2019 (COVID-19), with pneumonia and sepsis. Of the 10 cases, 4 had dissecting pseudoaneurysms (40%), 3 in the posterior circulation and 1 in the anterior circulation. Among 6 saccular/blister aneurysms, 4 (67%) were ≤4 mm in largest diameter., Conclusions: Our experience with aneurysmal subarachnoid hemorrhage in patients positive for COVID-19 reveals a possibly distinct pattern compared with traditional aneurysmal subarachnoid hemorrhage, namely a high frequency of small aneurysms, dissecting pseudoaneurysms, and young patients., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Delayed cerebral ischemia is a major predictor of poor outcomes in patients who suffer subarachnoid hemorrhage. Treatment options are limited and often ineffective despite many years of investigation and clinical trials. Modern advances in basic science have produced a much more complex, multifactorial framework in which delayed cerebral ischemia is better understood and novel treatments can be developed. Leveraging this knowledge to improve outcomes, however, depends on a holistic understanding of the disease process. We conducted a review of the literature to analyze the current state of investigation into delayed cerebral ischemia with emphasis on the major themes that have emerged over the past decades. Specifically, we discuss microcirculatory dysfunction, glymphatic impairment, inflammation, and neuroelectric disruption as pathological factors in addition to the canonical focus on cerebral vasospasm. This review intends to give clinicians and researchers a summary of the foundations of delayed cerebral ischemia pathophysiology while also underscoring the interactions and interdependencies between pathological factors. Through this overview, we also highlight the advances in translational studies and potential future therapeutic opportunities.

Background: CSF shunting is among the most widely utilized interventions in patients with idiopathic intracranial hypertension (IIH). Ventriculoperitoneal shunting (VPS) and lumboperitoneal shunting (LPS) are 2 possible treatment modalities., Objective: To evaluate and compare complications, malfunction, infection, and revision rates associated with VPS compared to LPS., Methods: Electronic medical records were reviewed to identify baseline and treatment characteristics for patients diagnosed with IIH treated with VPS or LPS., Results: A total of 163 patients treated with either VPS (74.2%) or LPS (25.8%) were identified. The mean follow-up was 35 mo. Shunt revision was required in 40.9% of patients. There was a nonsignificant higher rate of revision with LPS (52.4%) than VPS (36.4%, P = .07). In multivariate analysis, increasing patient age was associated with higher odds of shunt revision (P = .04). LPS had higher odds of shunt revision, yet this association was not significant (P = .06). Shunt malfunction was the main indication for revision occurring in 32.7%, with a significantly higher rate with LPS than VPS (P = .03). In total, 15 patients had shunt infection (9.4% VPS vs 12.2% LPS P = .50). The only significant predictor of procedural infection was the increasing number of revisions (P = .02)., Conclusion: The incidence of shunt revision was 40.9%, with increasing patient age as the sole predictor of shunt revision. The incidence of shunt malfunction was significantly higher in patients undergoing LPS, while there was no significant difference in the incidence of shunt infection between the 2 modalities., (© Congress of Neurological Surgeons 2021.)

Purpose: Follow-up MRI/MRA is historically obtained as outpatient when patients with a spontaneous intracerebral hemorrhage (ICH) have an initial MRI/MRA that is negative for an underlying structural lesion. However, the utility of repeating MR imaging in a delayed fashion remains uncertain., Methods: We retrospectively reviewed 396 patients with spontaneous ICH admitted at our institution between 2015 and 2017 and selected those whose initial MRI/MRA was negative for an underlying structural lesion and those who underwent follow-up MR imaging in a delayed fashion., Results: A total of 113 patients met the study criteria. The average age of those with negative follow-up MRI/MRA was 65.0 ± 12.6 (IQR: 55.0-74.0) years old. None of the 113 patients with a negative inpatient MRI/MRA had an underlying structural lesion on follow-up MRI/MRA (0%, 95% CI 0.0-0.032, p < 0.001). The mean time of the follow-up imaging from the initial study was 105.7 days (median: 62 days; IQR: 42.5-100.5). Of the 113, 83 (73.5%) underwent follow-up MRI with and without gadolinium, while 30 (26.5%) patients did not receive gadolinium., Conclusion: Delayed follow-up MRI in patients with a negative initial MRI/MRA for workup of spontaneous ICH was not diagnostic in any of the patients included in the study. Our study suggests that a routine follow-up MRI for this patient population is not necessary.

Background: The transradial access (TRA) is rapidly gaining popularity for neuroendovascular procedures as there is strong evidence for its benefits compared to the traditional transfemoral access (TFA). However, the transition to TRA bears some challenges including optimization of the interventional suite set-up and workflow as well as its impact on fellowship training., Objective: To compare the learning curves of TFA and TRA for diagnostic cerebral angiograms in neuroendovascular fellowship training., Methods: We prospectively collected diagnostic angiogram procedural data on the performance of 2 neuroendovascular fellows with no prior endovascular experience who trained at our institution from July 2018 until June 2019. Metrics for operator proficiency were minutes of fluoroscopy time, procedure time, and volume of contrast used., Results: A total of 293 diagnostic angiograms were included in the analysis. Of those, 57.7% were TRA and 42.3% were TFA. The median contrast dose was 60 cc, and the median radiation dose was 14 000 μGy. The overall complication rate was 1.4% consisting of 2 groin hematomas, 1 wrist hematoma, and 1 access-site infection using TFA. The crossover rate to TFA was 2.1%. Proficiency was achieved after 60 femoral and 95 radial cases based on fluoroscopy time, 52 femoral and 77 radial cases based on procedure time, and 53 femoral and 64 radial cases based on contrast volume., Conclusion: Our study demonstrates that the use of TRA can be safely incorporated into neuroendovascular training without causing an increase in complications or significantly prolonging procedure time or contrast use., (© Congress of Neurological Surgeons 2021.)

Background: The radial approach has been gaining more widespread use by neurointerventionalists fueled by data from the cardiology literature showing better safety and overall reduced morbidity., Objective: To present our institution's experience with the radial approach for neuroendovascular interventions in 614 consecutive patients who underwent a cumulative of 760 procedures., Methods: A retrospective analysis was performed and identified neuroendovascular procedures performed via the upper extremity vasculature access site., Results: Amongst 760 procedures, 34.2% (260) were therapeutic, and 65.7% (500) were nontherapeutic angiograms. Access sites were 71.5% (544) via a conventional radial artery, 27.8% (211) via a distal radial artery, 0.5% (4) via an ulnar artery, and 0.1% (1) via the brachial artery. Most of the procedures (96.9%) were performed via the right-sided (737), 2.9% (22) via the left-sided, and 0.1% (1) via a bilateral approach. Major access site complications occurred at a rate of 0.9% (7). The rate of transfemoral conversion was 4.7% (36). There was a statistically higher incidence of transfemoral conversion when repeat procedures were performed using the same access site. Also, there was no significant difference between nontherapeutic procedures performed using the right and left radial access, and conventional versus distal radial access. Procedural metrics improved after completion of 14 procedures, indicating a learning curve that should be surpassed by operators to reach optimal outcomes., Conclusion: Radial artery catheterization is a safe and effective means of carrying out a wide range of neuroendovascular procedures associated with excellent clinical outcomes and an overall low rate of periprocedural complications., (© Congress of Neurological Surgeons 2021.)

Background: Aneurysms associated with fenestrations of intracranial arteries are exceptionally rare findings. Management strategies for these aneurysms are not well-defined, especially regarding endovascular treatment. We sought to investigate the strategies and feasibility of endovascular treatment approaches for various fenestration-associated intracranial aneurysms., Methods: We performed a retrospective chart review of 2000 aneurysms treated endovascularly, identifying 8 aneurysms located at arterial fenestrations. The technical details and procedural outcomes were reviewed to identify common management approaches, technical nuances, and treatment outcomes., Results: There were 3 (37.5%) aneurysms associated with fenestrations of the basilar artery or vertebrobasilar junction. All 3 were successfully treated with a previously undescribed coil-assisted flow-diversion technique, resulting in complete obliteration. Three (37.5%) aneurysms were associated with fenestrations of the anterior communicating artery. Of those, 2 were successfully treated with stent-assisted coil embolization and 1 with coil embolization alone. One (12.5%) aneurysm was associated with a fenestration of the paraclinoid internal carotid artery and 1 (12.5%) aneurysm found was at the takeoff of the posterior inferior cerebellar artery at a fenestration of the vertebral artery. Both were successfully treated with coil-assisted flow diversion. There were no permanent procedural complications. Major considerations for endovascular management of these aneurysms were the dominance of fenestration trunks, aneurysms arising from the fenestration apex or a fenestration limb, amenability to flow diversion, and anticipation of vascular remodeling., Conclusions: Fenestration-associated aneurysms are very rare. We have identified common factors to help guide decision-making for endovascular approaches and demonstrate successful aneurysm treatment using these methods., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Neuroangiography has seen a recent shift from transfemoral to transradial access. In transradial neuroangiography, the right dominant hand is the main access used. However, the left side may be used specifically for left posterior circulation pathologies and when right access cannot be used. This study describes our initial experience with left radial access for diagnostic neuroangiography and assesses the feasibility and safety of this technique. We performed a retrospective review of a prospective database of consecutive patients between April 2018 and January 2020, and identified 20 patients whom a left radial access was used for neurovascular procedures. Left transradial neuroangiography was successful in all 20 patients and provided the sought diagnostic information; no patient required conversion to right radial or femoral access. Pathology consisted of anterior circulation aneurysms in 17 patients (85%), brain tumor in 1 patient (5%), and intracranial atherosclerosis disease involving the middle cerebral artery in 2 patients (10%). The left radial artery was accessed at the anatomic snuffbox in 18 patients (90%) and the wrist in 2 patients (10%). A single vessel was accessed in 7 (35%), two vessels in 8 (40%), three vessels in 4 (20%), and four vessels in 1 (5%). Catheterization was successful in 71% of the cases for the right internal carotid artery and in only 7.7% for the left internal carotid artery. There were no instances of radial artery spasm, radial artery occlusion, or procedural complications. Our initial experience found the left transradial access to be a potentially feasible approach for diagnostic neuroangiography even beyond the left vertebral artery. The approach is strongly favored by patients but has significant limitations compared with the right-sided approach.