Large Stroke Research Articles

Impact of Procedure Time on First Pass Effect in Mechanical Thrombectomy for Anterior Circulation Acute Ischemic Stroke.

First pass effect (FPE) is a metric increasingly used to determine the success of mechanical thrombectomy (MT) procedures. However, few studies have investigated whether the duration of the procedure can modify the clinical benefit of FPE. We sought to determine whether FPE after MT for anterior circulation large vessel occlusion acute ischemic stroke is modified by procedural time (PT). A multicenter, international data set was retrospectively analyzed for anterior circulation large vessel occlusion acute ischemic stroke treated by MT who achieved excellent reperfusion (thrombolysis in cerebral infarction 2c/3). The primary outcome was good functional outcome defined by 90-day modified Rankin scale scores of 0-2. The primary study exposure was first pass success (FPS, 1 pass vs ≥2 passes) and the secondary exposure was PT. We fit-adjusted logistic regression models and used marginal effects to assess the interaction between PT (≤30 vs >30 minutes) and FPS, adjusting for potential confounders including time from stroke presentation. A total of 1310 patients had excellent reperfusion. These patients were divided into 2 cohorts based on PT: ≤30 minutes (777 patients, 59.3%) and >30 minutes (533 patients, 40.7%). Good functional outcome was observed in 658 patients (50.2%). The interaction term between FPS and PT was significant ( P = .018). Individuals with FPS in ≤30 minutes had 11.5% higher adjusted predicted probability of good outcome compared with those who required ≥2 passes (58.2% vs 46.7%, P = .001). However, there was no significant difference in the adjusted predicted probability of good outcome in individuals with PT >30 minutes. This relationship appeared identical in models with PT treated as a continuous variable. FPE is modified by PT, with the added clinical benefit lost in longer procedures greater than 30 minutes. A comprehensive metric for MT procedures, namely, FPE 30 , may better represent the ideal of fast, complete reperfusion with a single pass of a thrombectomy device.

Tobacco use and risk of acute stroke in 32 countries in the INTERSTROKE study: a case–control study

Smoking is a major risk factor for the global burden of stroke. We have previously reported a global population attributable risk (PAR) of stroke of 12.4% associated with current smoking. In this study we aimed to explore the association of current tobacco use with different types of tobacco exposure and environmental tobacco smoke (ETS) exposure on the risk of stroke and stroke subtypes, and by regions and country income levels. The INTERSTROKE study is a case-control study of acute first stroke and was undertaken with 13,462 stroke cases and 13,488 controls recruited between January 11, 2007 and August 8, 2015 in 32 countries worldwide. Association of risk of tobacco use and ETS exposure were analysed with overall stroke, ischemic and intracerebral hemorrhage (ICH), and with TOAST etiological stroke subtypes (large vessel, small vessel, cardioembolism, and undetermined). Current smoking was associated with an increased risk of all stroke (odds ratio [OR] 1.64, 95% CI 1.46-1.84), and had a stronger association with ischemic stroke (OR 1.85, 95% CI 1.61-2.11) than ICH (OR 1.19 95% CI 1.00-1.41). The OR and PAR of stroke among current smokers varied significantly between regions and income levels with high income countries (HIC) having the highest odds (OR 3.02 95% CI 2.24-4.10) and PAR (18.6%, 15.1-22.8%). Among etiological subtypes of ischemic stroke, the strongest association of current smoking was seen for large vessel stroke (OR 2.16, 95% CI 1.63-2.87) and undetermined cause (OR 1.97, 95% CI 1.55-2.50). Both filtered (OR 1.73, 95% CI 1.50-1.99) and non-filtered (OR 2.59, 95% CI 1.79-3.77) cigarettes were associated with stroke risk. ETS exposure increased the risk of stroke in a dose-dependent manner, exposure for more than 10h per week increased risk for all stroke (OR 1.95, 95% CI 1.69-2.27), ischemic stroke (OR 1.89, 95% CI 1.59-2.24) and ICH (OR 2.00, 95% CI 1.60-2.50). There are significant variations in the magnitude of risk and PAR of stroke according to the types of tobacco used, active and ETS exposure, and countries with different income levels. Specific strategies to discourage tobacco use by any form and to build a smoke free environment should be implemented to ease the global burden of stroke. The Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Canadian Stroke Network, Swedish Research Council, Swedish Heart and Lung Foundation, The Health & Medical Care Committee of the Regional Executive Board, Region Västra Götaland, and through unrestricted grants from several pharmaceutical companies with major contributions from Astra Zeneca, Boehringer Ingelheim (Canada), Pfizer (Canada), MERCK, Sharp and Dohme, Swedish Heart and Lung Foundation, UK Chest, and UK Heart and Stroke.

Status Epilepticus after mechanical thrombectomy: The role of early EEG assessment in Stroke Unit, clinical and radiological prognostication

BackgroundConvulsive (CSE) and non-convulsive (NCSE) Status Epilepticus are a complication in 0.2–0.3% ischemic strokes. Large stroke and cortical involvement are the main risk factors for developing SE. This study evaluates the prevalence of SE in patients treated with endovascular thrombectomy (EVT) through EEG recording within 72- h from admission. Moreover, we compared clinical, radiological, and outcome measures in SE and no-SE patients. Materials and MethodsWe collected retrospectively demographical and clinical characteristics of acute ischemic stroke patients who underwent EVT, admitted in the Stroke Unit (SU) of the University Hospital of Trieste between January 2018 and March 2020 who underwent EEG recording within 72- h from the symptoms’ onset. ResultsOut of 247 EVT patients, 138 met the inclusion criteria, of whom 9 (6.5%) showed SE with median onset time of 1 day (IQR 1–2). No difference was found between the two groups as for age, sex, risk factors, grade of recanalization, etiology of stroke, and closed vessel. The no-SE group presented higher NIHSS improvement rate (p=0.025) compared to the SE group. The sum of the lobes involved in the ischemic lesion was significantly higher in SE group (p=0.048). ConclusionSE after EVT in large strokes is a non-rare complication, with most being NCSE. Performing a rapid EEG assessment in a Stroke Unit setting may allow for a prompt recognition and treatment of SE in the acute/hyper-acute phase. SE may be correlated with worse clinical outcomes in patients with large vessel occlusion.

Prolonged venous transit on perfusion imaging is associated with higher odds of mortality in successfully reperfused patients with large vessel occlusion stroke

BackgroundPoor venous outflow (VO) profiles are associated with unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO), despite achieving successful reperfusion. The objective of this...

Performance analysis of a vapor injection linear compressor in a dual-temperature zone refrigerator

The vapor injection linear compressor exhibits a distinctive mass flowrate distribution characteristic compared to other vapor injection compressors, making it promising for application in dual-temperature zones refrigerating systems. In this study, a novel system of dual-temperature zone refrigerators featuring two parallel evaporators is proposed, and numerical models of the vapor injection linear compressor and its system are established, and then validated by experimental results. Theoretical analysis is conducted to explore the cooling performance and capacity-modulating characteristics of the system. Compared to traditional refrigeration systems, the vapor injection of medium-pressure refrigerant enhances the cooling capacity and performance at a large piston stroke while deteriorating the freezing capacity at a small piston stroke. This system offers the flexibility of adjusting the cooling ratio by modulating supply voltage and driving frequency to meet the cooling requirements. Correspondingly, special control strategies for this kind of system for the best performance are proposed in this study. Additionally, the structural parameters significantly influence the cooling performance: a larger injection area and a smaller distance to the top death center prove to be more advantageous for overall cooling performance. This research provides valuable insights for optimizing the structural parameters and control strategies, serving as a beneficial reference for future innovative refrigeration technologies.

Clinical uncertainty in large vessel occlusion ischemic stroke: does automated perfusion imaging make a difference? An intra-rater and inter-rater agreement study

BackgroundLimited research exists regarding the impact of neuroimaging on endovascular thrombectomy (EVT) decisions for late-window cases of large vessel occlusion (LVO) stroke.ObjectiveT0 assess whether perfusion CT imaging: (1) alters the...

Impact of Immune Cells on Stroke Limited to Specific Subtypes: Evidence from Mendelian Randomization Study.

Stroke is one of the common diseases that pose a severe threat to human health, with immune cells playing a crucial role in its onset and recovery. However, the specific mechanisms and causal relationships of different immune cell groups in various clinical stroke subtypes are unclear. This study explored the causal relationship between immune cells and stroke and its subtypes using Mendelian randomization (MR) analysis. Data from genome-wide association studies were analyzed using inverse-variance weighted (IVW), MR-Egger, and weighted median methods for MR analysis, along with heterogeneity tests, sensitivity analysis, and pleiotropy analysis. CD45RA+CD28-CD8+ Tcell %Tcell (OR 1.002, 95%CI 1.001-1.003; PFDR = 0.02), CD27 on CD24+CD27+ Bcell (OR 1.127, 95%CI 1.061-1.198; PFDR = 0.04), CD27 on IgD-CD38dim Bcell (OR 1.138, 95%CI 1.076-1.203; PFDR = 0.005), and CD27 on switched memory Bcell (OR 1.144, 95%CI 1.076-1.216; PFDR = 0.01) were found to increase the risk of large artery stroke. Switched memory Bcell %lymphocyte (OR 1.206, 95%CI 1.103-1.318; PFDR = 0.02) increased the risk of small vessel stroke. Reverse MR analysis did not reveal any reverse causal associations. Furthermore, by substituting the outcome data, a secondary MR analysis was conducted to validate the primary findings. Our study reveals several causal links between immune phenotypes and stroke and its different subtypes, highlighting the complex interactions between the immune system and stroke. These findings provide new directions for further uncovering the biological basis of stroke and assist in advancing research on early interventions and treatment strategies.

Does Ischemic Core Volume Modify the Treatment Effect of Endovascular Thrombectomy?

Imaging-based selection has become integral in guiding endovascular thrombectomy for large vessel occlusive stroke, driven by positive trial outcomes incorporating parenchymal and perfusion imaging criteria. While small-moderate core trials transformed acute reperfusion therapy, uncertainties persisted for large ischemic strokes. This was recently addressed in several treatment trials which demonstrated a benefit of endovascular thrombectomy in patients with large ischemic strokes, defined by parenchymal and/or perfusion imaging. Although individual trials suggest treatment benefits regardless of core size, patient-level meta-analyses are essential to clarify this relationship. Our aim was to summarize the imaging ramifications of the major endovascular thrombectomy trials of the past decade focusing on the interaction between the core and the treatment effect, to assist in the design of future meta-analyses. The core-treatment relationship that will be investigated in these meta-anlalyses will likely have major implications in our systems of care designs and in determining the utility of imaging-based selection.

Time-dependent systolic blood pressure within 72h after endovascular treatment in large vessel occlusion stroke.

The association of systolic blood pressure (SBP) and ischemic stroke outcome has recently been proved to be varied at different time points within 72h after acute ischemic stroke onset; however, the specific status of how SBP affects prognosis at different time points within 72h after endovascular treatment (EVT) among patients with large vessel occlusion (LVO) remains unclear. Consecutive LVO patients treated with EVT were enrolled in our study. BP data were collected at eight time points (1, 2, 4, 8, 16, 24, 48, and 72h post-EVT). Outcome measure of interest was functional dependence, which was defined as mRS >2 at 90 days. A total of 406 LVO patients treated with EVT from 2016 to 2022 were included. At 16h after EVT, the relationship between SBP and functional dependence showed a nonlinear association. At other time points after EVT, SBP had linear relationships with functional dependence. Furthermore, higher SBP, as either a linear or quadratic term, had an adverse effect on functional outcome. In addition, three SBP trajectories were observed, and the high-to-low group was independently associated with functional dependence. Taken together, higher SBP within the first 72h after EVT has a time-dependent association with adverse clinical outcomes. Optimal blood pressure management during the first 72h after EVT may be important to improve clinical outcome.

Anesthetic management for large vessel occlusion acute ischemic stroke with tandem lesions

BackgroundEndovascular therapy (EVT) stands as an established and effective intervention for acute ischemic stroke in patients harboring tandem lesions (TLs). However, the optimal anesthetic strategy for EVT in TL patients...

Brain imaging prior to thrombectomy in the late window of large vessel occlusion ischemic stroke: a systematic review and meta-analysis.

Optimal imaging modalities to select patients for endovascular thrombectomy (EVT) in the late window of acute ischemic stroke due to large vessel occlusions (AIS-LVO) are not known. We conducted a systematic review comparing outcomes of patients selected by non-contrast computed tomography (NCCT)/CT angiography (CTA) vs. those selected by CT perfusion (CTP) or magnetic resonance imaging (MRI) for EVT in these patients. We searched PUBMED, EMBASE, and the Cochrane Library from January 1, 2000, to July 15, 2023, to identify studies comparing outcomes of patients selected for EVT by NCCT/CTA vs. CTP or MRI in the late time window for AIS-LVO. Primary outcome was independence (mRS 0-2) at 90days or discharge. Secondary outcomes were symptomatic intracranial hemorrhage (sICH) and mortality. We pooled data across studies based on an inverse variance method. Six cohort studies with 4208 patients were included. Pooled results showed no significant difference in the rate of independence at 90days or discharge (RR 0.96, 95% CI 0.88-1.03) and sICH (RR 1.26, 0.85-1.86) between patients selected by NCCT/CTA vs. CTP or MRI for EVT in the late window of AIS-LVO. However, patients selected by NCCT/CTA vs. CTP or MRI for EVT were associated with a higher risk of mortality (RR 1.21, 1.06-1.39). For AIS-LVO in the late window, patients selected by NCCT/CTA compared with those selected by CTP or MRI for EVT might have a comparable rate of functional independence and sICH. Baseline NCCT/CTA may triage AIS-LVO in the late window.

The Association Between National Institutes of Health Stroke Scale Score and Clinical Outcome in Patients with Large Core Infarctions Undergoing Endovascular Treatment.

This study aimed to analyze the association between baseline National Institutes of Health Stroke Scale (NIHSS) scores and clinical outcomes in patients with large core infarctions undergoing endovascular treatment (EVT), a relationship that remains unclear. Data were obtained from the MAGIC study, a prospective multicenter cohort study focusing on patients with acute large core ischemic stroke. This analysis evaluated the impact of NIHSS scores on EVT outcomes in patients with large core infarctions. Primary outcome metrics included favorable outcomes (modified Rankin Scale [mRS] of 0-3 at 90days), while secondary outcomes encompassed shifts in mRS scores, functional independence (mRS score of 0-2), mRS score of 0-4, and successful recanalization rates. Adverse events considered were symptomatic intracranial hemorrhage (sICH) and mortality. A total of 490 patients were enrolled in this study. Higher baseline NIHSS scores were inversely correlated with favorable outcomes (adjusted odds ratio [OR] in model3, 0.848 [0.797-0.903], P < 0.001), particularly in patients with NIHSS scores above 20 (adjusted OR in model3, 0.518 [0.306-0.878] vs. 0.290 [0.161-0.523]). Regarding adverse events, higher baseline NIHSS scores significantly correlated with increased 90-day mortality rates (adjusted OR in model3, 1.129 [1.072-1.189], P < 0.001). This correlation became insignificant when baseline NIHSS scores exceeded 22. Additionally, baseline NIHSS scores partially mediated the association between age (indirect effect = - 0.0005, 19.39% mediated) and sex (indirect effect = 0.0457, 25.08% mediated) with the primary outcome. The findings indicate that higher baseline NIHSS scores correlate with poorer outcomes and increased mortality, particularly when scores exceed 20. Moreover, age and sex indirectly influence favorable outcomes through their association with baseline NIHSS scores.

Effect of concomitant usage of alteplase and mechanical thrombectomy for M1 middle cerebral artery occlusion on clinical outcome: a retrospective analysis of 457 patients from two centers.

Endovascular thrombectomy (EVT) and concomitant usage of intravenous alteplase (alteplase) in large vessel occlusion stroke may produce unwanted excess intracerebral hemorrhage (ICH). Whether this applies specifically to isolated occlusion of the M1 segment of the middle cerebral artery (MCA) is unknown. A retrospective study from two tertiary thrombectomy centers. ICH was determined according to Heidelberg Bleeding Classification (HBC). Factors associated with the occurrence of ICH in EVT alone vs. EVT with alteplase were evaluated using logistic regression analysis. Factors related to the clinical outcome as determined with a modified Rankin scale (mRS) were investigated with univariate and adjusted multivariate logistic regression analysis. The interaction between clinical variables and the usage of alteplase on the occurrence of ICH was evaluated. Any ICH occurred in 156/457 (34.1%) patients Class 1a bleeding in 37 (8.1%), type 2 in 45 (9.8%) Class 1c in 22 (4.8%), Class 2 in 25 (5.5%), and Class 3 (extraparenchymal) in 27 (5.9%). ICH occurred in similar frequency between alteplase-treated patients vs. EVT alone (85/262 [32%] vs. 71/195 [36%]; OR 1.19 (95% CI 0.81-1.76). After adjustment, odds for clinical outcome were lower in ICH patients (OR 0.44 [95% CI 0.25-0.74]), p = 0.002). Higher ICH rate was associated with more EVT steps (p for interaction -0.005), and usage of only stent-retriever (p for interaction =0.005). Utilization of alteplase alongside EVT for MCA M1 occlusion did not result in excessive ICH occurrences or clinical deterioration.

Late Lesion Growth following Endovascular Therapy: Is 24 h Too Early to Assess Acute Infarct Size Including the Effects of Secondary Injury?

Introduction: Stroke lesion volume on MRI or CT provides objective evidence of tissue injury as a consequence of ischemic stroke. Measurement of “final” lesion volume at 24-h following endovascular therapy (post-EVT) has been used in multiple studies as a surrogate for clinical outcome. However, despite successful recanalization, a significant proportion of patients do not experience favorable clinical outcome. The goals of this study were to quantify lesion growth during the first week after treatment, identify early predictors, and explore the association with clinical outcome. Methods: This is a prospective study of stroke patients at two centers who met the following criteria: (i) anterior large vessel occlusion acute ischemic stroke, (ii) attempted EVT, and (iii) had 3T MRI post-EVT at 24-h and 5-day. We defined “early” and “late” lesion growth as ≥10 mL lesion growth between baseline and 24-h diffusion-weighted imaging (DWI) and between 24-h DWI and 5-day fluid attenuated inversion recovery imaging, respectively. Complete reperfusion was defined as >90% reduction of the volume of tissue with perfusion delay (Tmax>6 s) between pre-EVT and 24-h post-EVT. Favorable clinical outcome was defined as modified Rankin scale (mRS) of 0–2 at 30 or 90 days. Results: One hundred twelve patients met study criteria with median age 67 years, 56% female, median admit NIHSS 19, 54% received IV or IA thrombolysis, 66% with M1 occlusion, and median baseline DWI volume 21.2 mL. Successful recanalization was achieved in 87%, and 68% had complete reperfusion, with an overall favorable clinical outcome rate of 53%. Nearly two-thirds (65%) of the patients did not have late lesion growth with a median volume change of −0.3 mL between 24-h and 5-day and an associated high rate of favorable clinical outcome (64%). However, ∼1/3 of patients (35%) did have significant late lesion growth despite successful recanalization (87%: 46% mTICI 2b/41% mTICI 3). Late lesion growth patients had a 27.4 mL change in late lesion volume and 30.1 mL change in early lesion volume. These patients had an increased hemorrhagic transformation (HT) rate of 68% with only 1 in 3 patients having favorable clinical outcome. Late lesion growth was independently associated with incomplete reperfusion, HT, and unfavorable outcome. Conclusion: Approximately 1 out of 3 patients had late lesion growth following EVT, with a favorable clinical outcome occurring in only 1 out of 3 of these patients. Most patients with no early lesion growth had no late lesion growth. Identification of patients with late lesion growth could be critical to guide clinical management and inform prognosis post-EVT. Additionally, it can serve as an imaging biomarker for the development of adjunctive therapies to mitigate reperfusion injury.

Shear stiffening gel-enabled twisted string for bio-inspired robot actuators

A rotary motor combined with fibrous string demonstrates excellent performance because it is powerful, lightweight, and prone to large strokes; however, the stiffness range and force-generating capability of twisted string transmission systems are limited. Here, we present a variable stiffness artificial muscle generated by impregnating shear stiffening gels (STGs) into a twisted string actuator (TSA). A high twisting speed produces a large impact force and causes shear stiffening of the STG, thereby improving the elasticity, stiffness, force capacity, and response time of the TSA. We show that at a twisting speed of 4186 rpm, the elasticity of an STG-TSA reached 30.92 N/mm, whereas at a low twisting speed of 200 rpm, it was only 10.51 N/mm. In addition, the STG-TSA exhibited a more prominent shear stiffening effect under a high stiffness load. Our work provides a promising approach for artificial muscles to coactivate with human muscles to effectively compensate for motion.

Association between acute stroke and COVID-19 infection among patients with acute stroke

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS COV 2) infection is associated with multiple neurological complications. Cerebrovascular accidents are considered as one of the common neurological complications associated with corona virus (COVID-19). It may represent the first presentation of the patients of COVID-19 or may occur anytime during the course of the disease.ResultsThis study included 381 patients after the diagnosis of cerebrovascular accident. The mean age of the participants was 57.1 ± 15 years. 53.5% of the participants were males and 46.5% were females. The participants had COVID-19 infection in past 3 months with mean duration was 35.5 ± 18 days. The mean NIHSS among the participants was 10.5 ± 6.2. Small artery stroke was higher among PCR negative patients and controls, while large artery stroke was higher among PCR positive patients. 26% of patients with stroke and confirmed COVID-19 infection developed stroke immediately after COVID-19 infection (within 1 week). Within 1 month from getting infection with COVID-19, 41.7% of patients developed stroke and 32.3% had developed stroke after 1 month of infection with COVID-19. Female gender, older age of the patients and presence of vascular risk factors were associated with increased severity of infection as evidenced by higher NIHSS and more ICU admission among COVID-19 positive patients.ConclusionsCOVID-19 infection has been associated with both venous and arterial stroke, especially in elderly patients. COVID-19 infection was associated with increased stroke severity as evidenced by higher NIHSS and more ICU admission. Small vessel disease was higher among COVID-19 negative patients, while large artery stroke was higher among positive COVID-19 patients.

Impact of Sex on Thrombectomy Outcomes in Ischemic Stroke: A Propensity Score‐Matched Study, Systematic Review, and Meta‐Analysis

Background Women are underrepresented in stroke thrombectomy trials, and the impact of sex differences in outcomes after stroke thrombectomy is unclear. We performed a multicenter propensity matching study to define sex‐related differences in outcome after endovascular thrombectomy and integrated results in a meta‐analysis. Methods We included patients with anterior circulation large vessel occlusion consecutively treated with thrombectomy at 2 Comprehensive Stroke Centres (2016–2023). Selection criteria reflected international guidelines. Through systematic review we selected all studies reporting endovascular thrombectomy outcomes in anterior circulation large vessel occlusion stroke, applying propensity score matching. MEDLINE, EMBASE, and Cochrane CENTRAL were searched up to August 15, 2023 according to predefined protocol (OSF.io/je3da). Data were extracted by 2 independent raters, pooled estimates calculated according to random‐effect modeling meta‐analysis and reported as odds ratio (OR) and standard 95% CI. Outcomes were good functional outcome, defined as modified Rankin Scale score 0–2 at 90 days after stroke, and symptomatic intracranial hemorrhage, adjudicated according to European Cooperative Acute Stroke Study II criteria. Results After matching, 698 patients (349 women versus 349 men) had similar cardiovascular risk factors, baseline features, and treatment approach. No significant differences were found for good functional outcome (OR = 0.89, 95% CI = 0.66–1.2) and symptomatic intracranial hemorrhage (OR = 1.00, 95% CI = 0.44–2.26) in the cohort study by sex. Systematic review identified 3 studies (n = 3706), all of high quality. No differences emerged in rates of good functional outcome (OR = 1.00, 95% CI = 0.79–1.21) or symptomatic intracranial hemorrhage (OR = 0.85, 95% CI = 0.60–1.19) depending on sex. Conclusion Women receiving endovascular thrombectomy for anterior circulation large vessel occlusion related stroke have similar rates of good functional outcome and symptomatic intracranial hemorrhage compared to men.

Radiomics-Based Prediction of Collateral Status from CT Angiography of Patients Following a Large Vessel Occlusion Stroke.

A major driver of individual variation in long-term outcomes following a large vessel occlusion (LVO) stroke is the degree of collateral arterial circulation. We aimed to develop and evaluate machine-learning models that quantify LVO collateral status using admission computed tomography angiography (CTA) radiomics. We extracted 1116 radiomic features from the anterior circulation territories from admission CTAs of 600 patients experiencing an acute LVO stroke. We trained and validated multiple machine-learning models for the prediction of collateral status based on consensus from two neuroradiologists as ground truth. Models were first trained to predict (1) good vs. intermediate or poor, or (2) good vs. intermediate or poor collateral status. Then, model predictions were combined to determine a three-tier collateral score (good, intermediate, or poor). We used the receiver operating characteristics area under the curve (AUC) to evaluate prediction accuracy. We included 499 patients in training and 101 in an independent test cohort. The best-performing models achieved an averaged cross-validation AUC of 0.80 ± 0.05 for poor vs. intermediate/good collateral and 0.69 ± 0.05 for good vs. intermediate/poor, and AUC = 0.77 (0.67-0.87) and AUC = 0.78 (0.70-0.90) in the independent test cohort, respectively. The collateral scores predicted by the radiomics model were correlated with (rho = 0.45, p = 0.002) and were independent predictors of 3-month clinical outcome (p = 0.018) in the independent test cohort. Automated tools for the assessment of collateral status from admission CTA-such as the radiomics models described here-can generate clinically relevant and reproducible collateral scores to facilitate a timely treatment triage in patients experiencing an acute LVO stroke.

Brush Sign on pre-treatment imaging is associated with good functional outcome in stroke patients treated with mechanical thrombectomy: A prospective monocentric study

BackgroundThe Brush Sign (BrS) is a radiological biomarker (MRI) showing signal decrease of subependymal and deep medullary veins on paramagnetic-sensitive magnetic resonance sequences. Previous studies have shown controversial results regarding the prognostic value of BrS. We aimed to assess whether BrS on T2*-weighted sequences could predict functional prognosis in patients treated with mechanical thrombectomy (MT). MethodsWe included all consecutive patients with large artery occlusion related stroke in anterior circulation treated with MT between February 2020 and August 2022 at Reims University Hospital. Multivariable logistic regression models were used to investigate factors associated with BrS and its impact on outcomes. ResultsOf the 327 included patients, 124 (37,9%) had a BrS on baseline MRI. Mean age was 72 ± 16 years and 184 (56,2 %) were female. In univariate analysis, BrS was associated with a younger age (67 vs 74; p<0.001), a higher NIHSS score (16(10–20) vs 13(8–19); p = 0.047) history of diabetes (15.3% vs 26.1 %; p = 0.022) and a shorter onset to MRI time (145.5 (111.3–188.5) vs 162 (126–220) p = 0.008). In multivariate analyses, patients with a BrS were younger (OR:0.970 (0.951 – 0.989)), tend to have a higher NIHSS score at baseline (OR:1.046 (1.000 – 1.094) and were less likely to have diabetes (OR: 0.433; 0.214–0.879). The presence of BrS was independently associated with functional independence (OR: 2.234(1.158–4,505) at 3 months but not with mortality nor with symptomatic intracerebral hemorrhage. ConclusionBrS on pre-treatment imaging could be considered as a biomarker of physiological adaptation to cerebral ischemia, allowing prolonged viability of brain tissue and might participate in the therapeutic decision.

Characterizing coma in large vessel occlusion stroke.

Coma is an unresponsive state of disordered consciousness characterized by impaired arousal and awareness. The epidemiology and pathophysiology of coma in ischemic stroke has been underexplored. We sought to characterize the incidence and clinical features of coma as a presentation of large vessel occlusion (LVO) stroke. Individuals who presented with LVO were retrospectively identified from July 2018 to December 2020. Coma was defined as an unresponsive state of impaired arousal and awareness, operationalized as a score of 3 on NIHSS item 1a. 28/637 (4.4%) patients with LVO stroke were identified as presenting with coma. The median NIHSS was 32 (IQR 29-34) for those with coma versus 11 (5-18) for those without (p < 0.0001). In coma, occlusion locations included basilar (13), vertebral (2), internal carotid (5), and middle cerebral (9) arteries. 8/28 were treated with endovascular thrombectomy (EVT), and 20/28 died during the admission. 65% of patients not treated with EVT had delayed presentations or large established infarcts. In models accounting for pre-stroke mRS, basilar occlusion location, intravenous thrombolysis, and EVT, coma independently increased the odds of transitioning to comfort care during admission (aOR 6.75; 95% CI 2.87,15.84; p < 0.001) and decreased the odds of 90-day mRS 0-2 (aOR 0.12; 95% CI 0.03,0.55; p = 0.007). It is not uncommon for patients with LVO to present with coma, and delayed recognition of LVO can lead to poor outcomes, emphasizing the need for maintaining a high index of suspicion. While more commonly thought to result from posterior LVO, coma in our cohort was similarly likely to result from anterior LVO. Efforts to improve early diagnosis and care of patients with LVO presenting with coma are crucial.