Assessment of Blood Loss during Neuroendovascular Procedures.

(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.

Evaluation of patients referred to the spine clinic via telemedicine and the impact on diagnosis and surgical decision-making.

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.

Focused selection of open cerebrovascular cases for residents interested in cerebrovascular neurosurgery / Selección enfocada de casos cerebrovasculares abiertos para residentes interesados en neurocirugía cerebrovascular

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. Result 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 (AU)

Introducción Las tendencias nacionales e internacionales continúan mostrando un mayor énfasis en las técnicas endovasculares para el tratamiento de la enfermedad cerebrovascular. Sin embargo, el neurocirujano cerebrovascular debe estar adecuadamente equipado para tratar a estos pacientes mediante técnicas tanto abiertas como endovasculares. Métodos La disminución de los casos cerebrovasculares abiertos por clipaje de aneurismas ha obligado a muchos alumnos a buscar becas cerebrovasculares abiertas para aumentar el volumen de casos. Se ha empleado una estrategia alternativa en nuestra institución, que es la identificación temprana del enfoque de subespecialidad con la autoselección impulsada por el residente de casos cerebrovasculares abiertos. Resultados Esto ha permitido a los recién graduados obtener una formación endovascular completa y un número significativo de casos cerebrovasculares abiertos para obtener competencia y exposición Discusión Abogamos por nuevos paradigmas de autoselección complementados con capacitación en simulación para evitar la necesidad de becas extendidas posteriores a la residencia (AU)

Cost Comparison: Evaluating Transfemoral and Transradial Access for Diagnostic Cerebral Angiography.

BACKGROUND: Modern medicine necessitates the delivery of increasingly complex health care while minimizing cost. Transradial access (TRA) for neuroendovascular procedures is becoming more common as accumulating data demonstrate fewer complications, improved patient satisfaction, and high rates of treatment success compared with the transfemoral access (TFA) approach; however, disparities in cost between these approaches remain unclear. We compared supply and equipment costs between TRA and TFA for diagnostic cerebral angiography and evaluate the specific items that account for these differences. METHODS: We reviewed all adult patients who underwent diagnostic cerebral angiography from July 1, 2019 to December 31, 2019. Data related to patient demographics, vascular access site, catheters used, cost of catheters, arterial access sheath use, cost of sheaths, closure devices used, and cost of closure devices were collected. RESULTS: The transradial approach resulted in higher price of radial access sheath; however, the overall cost of closure devices was much lower in TRA group than in the TFA cohort. There was no significant difference in the cost of catheters. Overall, the total supply costs for TRA cerebral angiography were significantly lower than those of TFA cerebral angiography. The relative materials cost difference of using TRA was 20.9%. CONCLUSION: This study is the first itemized materials cost analysis of TRA versus TFA cerebral angiography. TRA necessitates the use of a more expensive access sheath device; however, this cost is offset by the increased cost of devices used for femoral arteriotomy closure. Overall, the supply and equipment costs were significantly lower for TRA than TFA.

Focused selection of open cerebrovascular cases for residents interested in cerebrovascular neurosurgery.

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.

Investigation and modulation of interleukin-6 following subarachnoid hemorrhage: targeting inflammatory activation for cerebral vasospasm.

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.

The Evolution of Endovascular Therapy for Intracranial Aneurysms: Historical Perspective and Next Frontiers.

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.

Predictors of first-pass reperfusion for mechanical thrombectomy in acute ischemic stroke.

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.

Delayed cerebral ischemia: A look at the role of endothelial dysfunction, emerging endovascular management, and glymphatic clearance.

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.

Timing surgery and hemorrhagic complications in endocarditis with concomitant cerebral complications.

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.

Preoperative prediction of postoperative urinary retention in lumbar surgery: a comparison of regression to multilayer neural network.

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.

The Woven EndoBridge (WEB) device: feasibility, techniques, and outcomes after FDA approval.

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.

Predictors of aneurysm occlusion following treatment with the WEB device: systematic review and case series.

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.

Ticagrelor resistance: a case series and algorithm for management of non-responders.

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.

Understanding the genetics of intracranial aneurysms: A primer.

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.

Adropin decreases endothelial monolayer permeability after cell-free hemoglobin exposure and reduces MCP-1-induced macrophage transmigration.

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.

Aneurysmal Subarachnoid Hemorrhage in Patients with Coronavirus Disease 2019 (COVID-19): A Case Series.

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.

Pathophysiology of Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: A Review.

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.