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Background This study proposes a modification to the traditional Hunt and Hess (tHH) grading scale for prognostication in aneurysmal subarachnoid hemorrhage (aSAH), which differentiates the most severe‐grade patients based on the presence or absence of brainstem dysfunction [determined by Glasgow Coma Scale (GCS) scores 3‐5]. Methods Weighted aSAH hospitalizations were retrospectively identified in the National Inpatient Sample from 2015 to 2019 and were stratified by tHH and modified HH (mHH) grades. mHH grade 5 was defined as tHH grade 5 with GCS score 3–5, while mHH grade 4 comprised tHH grade 5 with GCS score 6–8 and tHH grade 4. HH grades 1–3 do not differ between the traditional and modified scales. Measures of diagnostic performance were compared for the primary study end point [poor outcome as determined by the previously validated NIS‐SAH Outcome Measure (NIS‐SOM), shown to have high concordance with modified Rankin Scale scores > 2]. External validation of the mHH was performed using data from a prospectively maintained aSAH registry. Results Among 6130 aSAH hospitalizations, 2245 (36%) were tHH grade 5. Seven hundred and eighty‐five (35%) of these had a GCS 3–5 and were designated as mHH grade 5. Poor outcomes were identified in 78% and 77% of grade 4 tHH and mHH, respectively, and in 83% and 95% of grade 5 tHH and mHH, respectively. In comparison with the tHH, the mHH achieved superior discrimination [c‐statistic 0.793 (95% CI 0.768, 0.818) versus 0.780 (95% CI 0.750, 0.807); DeLong p < 0.001] for poor outcome, as well as improved specificity (0.929 versus 0.304) and positive predictive value (PPV) (0.949 versus 0.827). External registry validation of the mHH demonstrated excellent discrimination [c‐statistic 0.835 (95% CI 0.801, 0.870)], with a specificity of 0.950 and PPV of 0.905. Conclusion The mHH achieved a favorable diagnostic performance profile using retrospective data and may aid in the prognostication of high‐severity patients with aSAH.

Background Mechanical thrombectomy has become the standard of care for treatment of acute ischemic stroke secondary to large‐vessel occlusion up to 24 hours from last known normal time. Multiple different techniques for mechanical thrombectomy have been described, including a direct aspiration first‐pass technique and stent retriever thrombectomy. With a direct aspiration first‐pass technique, classically, a large‐bore aspiration catheter is delivered over a microcatheter and microwire to the clot. Recently, a novel macrowire has been introduced as a potential alternative to the use of microwire–microcatheter to allow the delivery of the aspiration catheter. The aim of this study is to develop a multicenter registry comparing delivery of an aspiration catheter for intracranial thrombectomy for acute ischemic stroke secondary to emergent large‐vessel occlusion over a macrowire in comparison with traditional use of microcatheter and microwire. Methods MINT (Macrowire for Intracranial Thrombectomy) is a multicenter, observational study currently enrolling patients with large‐vessel occlusion who underwent mechanical thrombectomy using a macrowire to deliver the aspiration catheter to the intracranial occlusion. All the participating sites will screen and report cases on a monthly basis. The decision to use the macrowire and various aspiration catheters is at the discretion of the interventionalist. Results We will collect patient's clinical, demographic, and radiographic data. In addition, we plan to collect procedure variables and postprocedure clinical and imaging data. Outcomes include successful delivery of the reperfusion catheter to the clot interface, time taken from groin access to first pass, and a bailout strategy for thrombectomy in cases where this is not feasible. Conclusion The MINT registry will add to our understanding of safety and efficacy of this novel macrowire in intracranial thrombectomy. This registry will also highlight and allow for understanding in workflow improvements from simplifying setup and possibly cost effectiveness of this technique.

Introduction Despite the well‐established potent benefit of mechanical thrombectomy (MT) for large vessel occlusion (LVO) stroke, access to MT remains low globally, particularly in Africa. We compared the access to MT in Africa versus access in other regions of the globe. Methods Mission Thrombectomy conducted a survey in 75 countries between November 22, 2020, and February 28, 202 to assess the access to mechanical thrombectomy and its determinants. Mechanical thrombectomy access (MTA) was defined as the estimated proportion of patients with LVO receiving MT annually. The current MT operator availability was defined as ([current MT operators x 50/current annual number of estimated thrombectomy‐eligible LVOs] x 100) and the current MT center availability was defined as ([current MT centers x 150/current annual number of estimated thrombectomy‐eligible LVOs] x 100). Baseline survey responses in Africa versus the rest of the world were summarized using descriptive statistics. Between group differences in baseline characteristics were evaluated using the Wilcoxon rank‐sum test Results Of all 61 countries included in the final analysis, 14.8% (n=9) were from the African continent. Median MT access in Africa (0.4%) was about 10% of that of the rest of the world (4.9%). Country‐level summary characteristics of different determinants of MT access in Africa vs the rest of the world are presented in Table 1. Less than 50% of African countries (44.4%) have prehospital medical services, compared to 84.6% in the rest of the world (p‐value for comparison =0.007). In generalized linear models, LVO stroke patients in Africa had 90% lower odds of MT access when compared to the rest of the world (OR 0.10, 95%CI 0.04‐0.22). Conclusion Access to MT in Africa is extremely low and far below that of other regions of the globe. Public health interventions must be prioritized to increase access to MT in the continent of Africa.

Introduction Tandem Lesions (TLs) pose unique challenges in the endovascular management of acute ischemic stroke.(1) The absence of anterograde blood flow in the carotid occluded segment may limit the effectiveness of endovascular interventions, resulting in delayed reperfusion or suboptimal recanalization.(2,3) Thus, the presence of unpaired blood flow through the ICA in the context of TLs is believed to exacerbate the extension of ischemic lesions. (4,5) This study compared the clinical and procedural outcomes of patients with TLs and extracranial internal carotid artery occlusion versus those with stenosis. Methods A retrospective analysis was performed on a multicenter cohort of patients with TLs who underwent endovascular treatment. The patients were categorized into two groups: those with extracranial ICA stenosis and those with occlusion. Clinical outcomes, including functional independence, hemorrhagic events, and procedural time metrics including puncture to reperfusion time were assessed. Sensitivity analyses were conducted to evaluate these differences segregating patients according to varying degrees of stenosis, and in pre‐specified subgroups. Results A total of 513 patients with TLs were included in the study. 281 (54.8%) presented with ICA occlusion, and 232 (45.2%) presented stenosis >=70% (Table 1). The comparison between the stenosis and occlusion groups revealed no significant differences in the main outcomes, including mTICI 2c‐3 (47.5% vs. 50.6%, aOR 1.07, 95% CI 0.70‐1.64, p=.751) (Figure 1), mRS 0‐2 at 90 days (43.6% vs. 48.9%, aOR 0.79, 95% CI 0.52‐1.20, p=.271), sICH rates (4.7% vs. 5.6%, aOR 0.72, 95% CI 0.31‐1.71, p=.458), and puncture to reperfusion time (58 [40‐80.5] vs. 52.5 [35.2‐80], ratio 1.04, 95% CI 0.88‐1.23, p=.64). Similar analyses performed comparing different degrees of stenosis and occlusion, and in patients treated with the antegrade approach only, did not show significant differences either. Conclusion Our findings indicate that although more severe degrees of stenosis or occlusion of the ICA prolong the time from puncture to reperfusion, no significant differences in clinical outcomes exist. The clinical implications of these findings need to be further evaluated to fully comprehend the specific needs of patients affected by TLs.

Introduction Tandem lesions (TLs) are present in up to 15% of patients with stroke due to acute large vessel occlusions.(1) Nevertheless, published research on endovascular treatment outcomes in this population is scarce. Although TLs are most commonly of atherosclerotic etiology, some patients present with dissection of the ICA.(2, 3) In this study, we compared the clinical outcomes of TL patients with the two etiologies. Methods A retrospective analysis was performed on a multicenter cohort of patients with TLs who underwent endovascular treatment. The patients were categorized into two groups according to the etiology of the ICA lesion: atherosclerosis and dissection. Patients were matched by baseline characteristics. Clinical outcomes, including recanalization success, functional independence and hemorrhagic events were assessed with multivariable analyses. Results Of 691 patients from the database, 526 met the inclusion criteria of this study. 467 (88.8%) patients presented with atherosclerosis of the ICA, and 59 (11.2%) patients presented dissection. Univariable differences were found in median age (69 y. [IQR 61 ‐ 76] vs. 52 y. [IQR 44 ‐ 63], p

Introduction The Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial published in 2010 showed aggressive medical therapy is superior to percutaneous transluminal angioplasty and stenting (PTAS) for intracranial atherosclerotic disease (ICAD). Following the pivotal positive mechanical thrombectomy (MT) trials in 2015, MT utilization in the United States (US) has increased. Rescue ICAD stenting may be needed in MT patients with underlying ICAD but it remains uncertain whether PTAS use for ICAD has changed over this time. The aim of this study is to describe national trends in the utilization of PTAS for ICAD in the US before and after SAMMPRIS and following the pivotal MT trials. Methods We used a constellation of International Classification of Diseases ninth and tenth revision diagnostic/procedural codes to identify all elective and non‐elective adult (> = 18 years) ICAD admissions with or without infarction containing concomitant codes for PTAS in the 2007–2019 National Inpatient Sample. Admissions containing codes for subarachnoid hemorrhage, unruptured intracranial aneurysms or benign intracranial hypertension were excluded. We combined weighted counts of PTAS admissions with annual US adult census data to obtain prevalence of PTAS. We used joinpoint regression to evaluate trends in PTAS use over time. Results Across the study period, there were 16,477 weighted admissions for ICAD undergoing PTAS in the US. 52.4% of these admissions were in patients 60–79years and 43.2% were in women. 74.3% of these admissions were non‐elective and this proportion increased over time (P = 0.019). 26.5% of all admissions had concurrent codes for MT but this proportion increased by almost ten‐fold over time from 4.3% in 2007 to 40.0% in 2019. On join point regression, PTAS utilization increased but insignificantly from 3.0/million population in 2007 to 5.7/million population in 2010 (Annualized percentage change, APC 11.2%, 95%CI ‐11.8 to 40.3, p = 0.290), declined also insignificantly from 2010–2013 (APC ‐13.2, 95%CI ‐48.4 to 45.8, p = 0.514) and increased significantly from 3.55/million in 2013 to 3.80/million in 2014 and exponentially across the rest of the period to 8.4 cases/million in 2019 (APC 15.4, 95%CI 9.2 to 22.0, p = 0.001). Upon stratification by admission type, most of the increase across the period 2013/2014 to 2019 occurred in non‐elective admissions (Figure 1). Utilization in elective admissions varied from 0.92 to 1.96 cases per million population but this did not change significantly across the study period. Conclusions PTAS utilization for ICAD declined in the US after SAMMPRIS but has increased following publication of pivotal MT trials mainly in non‐elective admissions. PTAS utilization increased significantly following publication of pivotal MT trials likely in ICAD patients who required rescue stenting.. Additional prospective studies are needed to determine the long‐term outcomes of concurrent PTAS and MT as this is not a group of patients that was studied in SAMMPRIS.

Introduction Recent studies have shown beneficial effects of Carotid artery stenting (CAS) in acute ischemic stroke patients with tandem lesions (TL). However, stent placement requires the use of antiplatelet medications to prevent in‐stent thrombosis and re‐occlusion of the artery. This must be balanced with the risk of intracerebral hemorrhage. In this multicenter study, we aimed to investigate the safety and feasibility of using antiplatelet regimens in patients with anterior circulation stroke with TLs. Methods Patient level data were pooled from 17 centers and included patients with intracranial occlusion of ICA or M1/M2 segment of MCA with a concomitant extracranial ICA occlusion or stenosis ≥ 50%. Inclusion criteria were; age ≥ 18 years, EVT for intracranial occlusion, and underwent treatment for extracranial ICA lesions demonstrated on CTA and/or DSA. Patients were divided into groups according to the number of antiplatelets administered at the time of endovascular therapy (EVT) procedure into four groups including; 1) no antiplatelets, 2) single oral antiplatelet, 3) dual antiplatelets, and 4) intravenous antiplatelets (in combination of single or dual antiplatelets). Multivariable logistic regression models with multiple imputations were built to assess the association of primary outcome; symptomatic intracranial hemorrhage (sICH), and secondary outcomes including; modified Rankin Score (mRS) 0–2 at 90 days, and successful reperfusion (mTICI score ≥ 2b). Results A total of 682 patients were included. Of these, 138 (20.2%) did not receive any antiplatelet therapy, while 143 (20.97%) were treated with single oral, 207 (30.35%) with dual oral, and 194 (28.5%) with intravenous combined with single or dual antiplatelets. The rate of favorable outcome was non‐significantly higher in the dual (53%) and IV‐combination (54.4%) antiplatelets, as compared with single (38.9%) and without antiplatelet (38.6%) medications. In the multivariable model, after adjusting, there was no significant differences in the sICH (single: aOR: 1.07, CI: 0.62‐1.84, p = 0.8, dual: aOR: 1.18, CI: 0.70‐1.99, p = 0.55, IV‐combination: aOR: 1.01, CI: 0.57‐1.78, p = 0.98) and functional outcome at 90 days (single: aOR: 1.15, CI: 0.63‐2.12, p = 0.64, dual: aOR: 1.03, CI: 0.55‐1.9, p = 0.9, IV‐combination: aOR: 0.83, CI: 0.42‐1.64, p = 0.59) among the study groups. Interestingly, successful reperfusion (mTICI score ≥ 2b) was significantly higher in dual oral and IV‐combination antiplatelets (single: aOR: 1.14, CI: 0.61‐2.14, p = 0.69, dual: aOR: 4.82, CI: 2.23‐10.42, p = < 0.001, IV‐combination: aOR: 3.65, CI: 1.71‐7.79, p = 0.001). Conclusions Administration of antiplatelet medications during EVT was associated with successful reperfusion without increasing the rate of symptomatic hemorrhage in patients with anterior circulation LVO with TLs. Further large‐scale randomized studies are warranted to validate the optimal antiplatelet regimens during acute carotid artery stenting in patients with TLs.

Introduction Public stroke education campaigns have traditionally utilized mass media. We hypothesized that a worldwide stroke awareness social media campaign, utilizing dance videos to express the BE‐FAST acronym for stroke signs and symptoms, could reach a large audience at a low cost. Methods Mission Thrombectomy 2020+ officially launched the #BEFASTChallenge, a Social Media (SoMe) public stroke educational campaign, on May 15, 2022, World Stroke Thrombectomy Day, after an internal “lead‐in” phase starting the first week of May 2022. The campaign was volunteer designed and implemented. The public and their followers were encouraged to post a video of their dance depicting each letter of BE‐FAST, tag the post with #BEFASTChallenge, and nominate others to participate. We tracked the SoMe posts from May 4th through July 13, 2022, on Facebook (FB), Twitter (TW), and Instagram (IG) platforms by searching #BEFASTChallenge on each SoMe site. We ascertained campaign adoption, public reach, and interaction by measuring original posts, views, likes, retweets, shares, and comments. Results There were 4 countries represented in the original posts on SoMe with the vast majority being from the US. The first post was on May 4, and the last was on July 13 (71 days), resulting in a daily average of 0.55 posts. The largest number of posts occurred on the launch date (16 posts). There were 39 original posts, which accumulated 170 retweets, 44 quote tweets, 755 likes, 32 comments, and 14 shares. The videos had 13,821views (Table 1). Conclusions We report that the preliminary analysis of a volunteer‐driven SoMe public stroke campaign utilizing dance to express stroke symptoms demonstrates feasibility, reaching a modest audience directly with good interaction. A similar professionally implemented SoMe campaign could lead to increased and more sustained user engagement to raise public stroke symptom awareness.

Introduction Continued advancements in the treatments for neurological disease have helped interventionalists to refine approaches that offer improved surgical efficacy and patient outcomes. Carotid‐artery stenting (CAS) is a safe and effective alternative to carotid endarterectomy (CEA), that allows for revascularization of the internal carotid artery (ICA) in a minimally‐invasive manner. Traditionally, the mainstay for CAS has been through the femoral artery; however, patients with carotid‐artery disease (CAD) often have concomitant peripheral artery disease which confer increased risk of significant life‐threatening access‐site complications, such as retroperitoneal hematoma and limb ischemia. Given this, CAS via the radial artery has become increasingly popular. This study seeks to investigate the safety and feasibility of the transradial approach (TRA), in comparison to the traditional transfemoral approach (TFA), for carotid‐artery stenting. Methods The authors conducted a retrospective analysis of all adult patients (age >18) who underwent carotid‐artery stenting via TRA or TFA over a 4‐year study period (2018‐2021) across 4 different international academic centers. Important variables, such as patient demographics, comorbidities, procedural details, results, and complications were collected. Statistical analysis was performed to assess the strength of association and correlation for these variables. Results A total of 313 patients were enrolled during the study period. CAS via TFA was attempted in 251 patients and via TRA in 62 patients, respectively. Overall, CAS via TRA was found to be successful in 48/62 (76%) patients, and via TFA in 246/251 (98%) patients. Baseline demographics were similar for the two groups, with a female gender predilection, median age of 69, and hypertension and hyperlipidemia serving as the most common medical comorbidities. 14/62 (22.6%) patients who underwent TRA were converted to TFA. Spasm of the radial artery, kinking of the catheter and severe tortuosity of the vessels were the primary reasons for access site conversion. A total of five major access site‐related complications, including two deaths, and seven minor complications were noted in the TFA cohort. No serious access related complications were noted in the TRA group. In the multivariate‐analysis, after adjusting for age, hyperlipidemia, chronic heart failure, combination of stent plus angioplasty and fluoroscopy times, there was no statistically significant difference observed among the 2 groups in terms of procedural (OR: 0.31; CI: 0.36‐2.69; P = 0.29) and overall access site complications (OR: 0.17, CI: 0.02‐1.98, P = 0.16). Conclusions TRA seems to be a safe alternative approach for carotid stenting. In our cohort, no serious access site‐related complications were noted with TRA in comparison to the TFA group. Continued improvements in terms of patient selection, sample size, as well as advances in technique and technology will help to further refine TRA for CAS. Further studies and analysis will need to be performed to delineate the crucial variables that contribute to improved functional outcomes for these patients.

Introduction There are two approaches for treating stroke patients with tandem occlusions: the anterograde approach (AA, extracranial lesions first) and the retrograde approach (RA, intracranial lesion first). Both techniques are associated with favorable functional outcomes. We aimed to compare both techniques for efficacy and safety outcomes in a multicenter study. Methods Patient data were pooled from 17 centers and divided into AA and RA groups. We performed multivariable logistic regressions to evaluate the association between each group with efficacy and safety outcomes. Results 552 patients were included in the study, 270 (48.4%) were treated with the AA, and 288 (51.6%) with the RA. There were no differences between groups for functional outcome (mRS 0–2) at 90 days (aOR = 0.93, 95%CI: 0.58‐1.48, p = 0.75), and successful reperfusion [mTICI >2b] (aOR = 0.83, 95%CI: 0.44‐1.56, p = 0.57). Similarly, we did not observe any differences for safety outcomes related to sICH (OR = 0.57, 95%CI: 0.25‐1.29, p = 0.18), parenchymal hematoma type 2 (OR = 0.61, 95%CI: 0.3‐1.22, p = 0.16), and all‐cause mortality at 90 days (OR = 1.22, 95%CI: 0.66‐2.26, p = 0.52). However, the median puncture‐to‐reperfusion time was higher in AA compared with RA [59 minutes (IQR: 38–92) vs 53.5 minuntes (IQR: 37–87)]. Conclusions The AA and RA approaches for the treatment of tandem occlusions seem to achieve similar efficacy and safety outcomes. These results are consistent with those of a previous multi‐center study. Additionally, and in line with previous research, there is a puncture‐to‐reperfusion time difference between both approaches, which suggests a potential benefit when using the RA. However, further prospective randomized studies are needed to elucidate its benefit in achieving better clinical outcomes.

The benefit of acute ischemic stroke (AIS) treatment is highly time dependent. Although studies on workflow improvement in AIS are increasingly gaining attention, there is a lack of consensus and consistency regarding the definition, measurement, and reporting of AIS workflow times. We discuss the challenges related to defining and measuring workflow times in AIS and propose a basic set of time intervals that should be reported in AIS workflow studies. We particularly focus on patients undergoing mechanical thrombectomy. Importantly, endovascular treatment workflow times should always be reported in conjunction with reperfusion quality because one is not informative without the other. We further suggest standardized reporting of workflow times that includes the 90th percentile in addition to medians and interquartile ranges, means, and SDs. The proposed methodology serves as a framework for AIS studies and aids further discussion on workflow‐related AIS research.

Introduction: More than a third of large vessel occlusion ischemic strokes do not have clear etiology. Mechanical thrombectomy provides a method to retrieve stroke‐causing thrombi and potentially identifying the etiology. A systematic meta‐analysis is performed to determine if there is a histological difference in red blood cell (RBC) composition of thrombi after the etiology of the stroke is known. Methods: We performed a systematic search through PUBMED and EMBASE. Studies meeting inclusion criteria were identified in which the large vessel occlusion stroke‐causing thrombi histology and etiology of the stroke were determined as either large artery atherosclerotic (LAA), cardioembolic (CE) or cryptogenic. Studies that had the data available or extractable data were selected. Random‐effect models were used to compare the histological difference between each etiology. Results: From inception to August 2021, 4 studies (n = 1022) were used to compare CE vs LAA, 5 studies (n = 1247) were used to compare CE vs cryptogenic and 4 studies (n = 654) were used to compare LAA vs cryptogenic. There was no significant difference in the red blood cells vs white blood cells/fibrin/platelets component between the stroke origins of CE vs LAA (mean difference (MD) ‐1.87; 95% confidence internal [CI]: ‐16.51, 12.78), CE vs cryptogenic (MD 1.18; 95% CI: ‐1.49, 3.86) and LAA vs cryptogenic (MD 7.20; 95% CI: ‐3.93, 18.34). Conclusions: There was no significant gross histological difference between CE, LAA and cryptogenic stroke etiologies and of the large vessel occlusion stroke‐causing thrombi retrieved by mechanical thrombectomy. Further studies into biochemical or genetic markers may be needed to identify stroke etiology.

Introduction: Stroke is a leading cause of morbidity, mortality and healthcare spending in the United States. Acute management of ischemic stroke is time‐dependent and evidence suggests improved clinical outcomes for patients treated at designated certified stroke centers. There is an increasing trend among hospitals to obtain certification as designated stroke centers. A common source or integrated tool providing both information and location of all available stroke centers in the US irrespective of the certifying organization is not readily available. The objective of our research is to generate a comprehensive and interactive electronic resource with combined data on all geographically‐coded certified stroke centers to assist in pre‐hospital triage and study healthcare disparities in stroke including availability and access to acute stroke care by location and population. Methods: Data on stroke center certification was primarily obtained from each of the three main certifying organizations: The Joint Commission (TJC), Det Norske Veritas (DNV) and Healthcare Facilities Accreditation Program (HFAP). Geographic mapping of all stroke center locations was performed using the ArcGIS Pro application. The most current data on stroke centers is presented in an interactive electronic format and the information is frequently updated to represent newly certified centers. Utility of the tool and its analytics are shown. Role of the tool in improving pre‐hospital triage in the stroke systems of care, studying healthcare disparities and implications for public health policy are discussed. Results: Aggregate data analysis at the time of submission revealed 1,806 total certified stroke centers. TJC‐certified stroke centers represent the majority with 106 Acute Stroke Ready (ASR), 1,040 Primary Stroke Centers (PSCs), 49 Thrombectomy Capable Centers (TSCs) and 197 Comprehensive Stroke Centers (CSCs). A total of 341 DNV‐certified programs including 36 ASRs, 162 PSCs, 16 PSC Plus (thrombectomy capable) and 127 CSCs were identified. HFAP‐certified centers (75) include 16 ASRs, 49 PSCs, 2 TSCs and 8 CSCs. A preliminary map of all TJC‐certified CSCs and TSCs is shown in the figure (1). Geospatial analysis reveals distinct areas with currently limited access to certified stroke centers and currently, access to certified stroke centers is extremely limited to non‐existent in fe States (for example: Idaho, Montana, Wyoming, New Mexico and South Dakota). Conclusions: Stroke treatment and clinical outcomes are time‐dependent and prompt assessment and triage by EMS directly to appropriate designated stroke centers is therefore critical. A readily available electronic platform providing location and treatment capability for all nearby certified centers will enhance regional stroke systems of care, including enabling more rapid inter‐hospital transfers for advanced intervention. Identifying geographic areas of limited access to treatment can also help improve policy and prioritize the creation of a more equitable and well‐distributed network of stroke care in the United States.

Background and Purpose: Moyamoya disease is a well described phenomenon presenting with terminal internal carotid artery occlusion and rete pattern of collateralization around the occlusion. The development of moyamoya-like collaterals secondary to isolated middle cerebral artery stenosis or occlusion and the natural history of this entity in Caucasians have not been well described. Methods: Cerebral angiograms and CT angiograms performed between August 2004 and August of 2006 demonstrating moyamoya collateralization at a single US center were retrospectively reviewed. All cases of middle cerebral artery stenosis associated with a rete pattern of collateralization were included in this series. Demographic, clinical, and angiographic data were obtained. Results: There were 3 cases of middle cerebral artery stenosis associated with a moyamoya pattern of collateralization. The average age of the patients was 36 years old, 2 were male, and all were Caucasian. All patients presented with ischemic symptoms. The average degree of stenosis was 91%. No stenosis was seen in the supraclinoid internal carotid arteries or elsewhere in the intracranial vasculature. Conclusion: We describe a moyamoya-like pattern of anastomosis associated with isolated severe middle cerebral artery stenosis or occlusion in Caucasians.

Background During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study’s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines.Methods We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March–31 May 2020. The prior 1-year control period (1 March–31 May 2019) was obtained to account for seasonal variation.Findings There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI −24.3% to −20.7%, p