Challenges to Widespread Implementation of Stroke Thrombectomy.

Endovascular treatment (EVT) for acute ischemic stroke is one of the most efficacious and effective treatments in medicine, yet globally, its implementation remains limited. Patterns of EVT underutilization exist in virtually any health care system and range from a complete lack of access to selective undertreatment of certain patient subgroups. In this review, we outline different patterns of EVT underutilization and possible causes. We discuss common challenges and bottlenecks that are encountered by physicians, patients, and other stakeholders when trying to establish and expand EVT services in different scenarios and possible pathways to overcome these challenges. Lastly, we discuss the importance of implementation research studies, strategic partnerships, and advocacy efforts to mitigate EVT underutilization.

Endovascular treatment to improve outcomes for medium vessel occlusions: The ESCAPE-MeVO trial.

RATIONALE: Clinical outcomes in acute ischemic stroke due to medium vessel occlusion (MeVO) are often poor when treated with best medical management. Data from non-randomized studies suggest that endovascular treatment (EVT) may improve outcomes in MeVO stroke, but randomized data on potential benefits and risks are hitherto lacking. Thus, there is insufficient evidence to guide EVT decision-making in MeVO stroke. AIMS: The primary aim of the ESCAPE-MeVO trial is to demonstrate that acute, rapid EVT in patients with acute ischemic stroke due to MeVO results in better clinical outcomes compared to best medical management. Secondary outcomes are to demonstrate the safety of EVT, its impact on self-reported health-related quality of life, and cost-effectiveness. SAMPLE SIZE ESTIMATES: Based on previously published data, we estimate a sample size of 500 subjects to achieve a power of 85% with a two-sided alpha of 0.05. To account for potential loss to follow-up, 530 subjects will be recruited. METHODS AND DESIGN: ESCAPE-MeVO is a multicenter, prospective, randomized, open-label study with blinded endpoint evaluation (PROBE design), clinicaltrials.gov: NCT05151172. Subjects with acute ischemic stroke due to MeVO meeting the trial eligibility criteria will be allocated in a 1:1 ratio to best medical care plus EVT versus best medical care only. Patients will be screened only at comprehensive stroke centers to determine if they are eligible for the trial, regardless of whether they were previously treated at a primary care center. Key eligibility criteria are (1) acute ischemic stroke due to MeVO that is clinically and technically eligible for EVT, (2) last-known well within the last 12 h, (3) National Institutes of Health Stroke Scale > 5 or 3-5 with disabling deficit, (4) high likelihood of salvageable tissue on non-invasive neuroimaging. STUDY OUTCOMES: The primary outcome is the modified Rankin scale 90 days after randomization (shift analysis), whereby modified Rankin Score 5 and 6 will be collapsed into one category. Secondary outcomes include dichotomizations of the modified Rankin Score at 90 days, 24 h National Institutes of Health Stroke Score, difference between 24 h and baseline National Institutes of Health Stroke Score, mortality at 90 days, health-related quality of life (EQ-5D-5 L), Lawton scale of instrumental activities of daily living score, reperfusion quality (MeVO expanded Thrombolysis in Cerebral Infarction Score) and infarct volume at 24 h, and cost-effectiveness of endovascular recanalization. Safety outcomes include symptomatic and asymptomatic intracranial hemorrhage and procedural complications. DISCUSSION: The ESCAPE-MeVO trial will demonstrate the effect of endovascular thrombectomy in addition to best medical management vis-à-vis best medical management in patients with acute ischemic stroke due to MeVO and provide data for evidence-based treatment decision-making in acute MeVO stroke. DATA ACCESS STATEMENT: The raw data discussed in this mansucript will be made available by the corresponding author upon reasonable request.

Infarcts Due to Large Vessel Occlusions Continue to Grow Despite Near-Complete Reperfusion After Endovascular Treatment.

BACKGROUND AND PURPOSE: Infarcts in acute ischemic stroke (AIS) patients may continue to grow even after reperfusion, due to mechanisms such as microvascular obstruction and reperfusion injury. We investigated whether and how much infarcts grow in AIS patients after near-complete (expanded Thrombolysis in Cerebral Infarction [eTICI] 2c/3) reperfusion following endovascular treatment (EVT), and to assess the association of post-reperfusion infarct growth with clinical outcomes. METHODS: Data are from a single-center retrospective observational cohort study that included AIS patients undergoing EVT with near-complete reperfusion who received diffusion-weighted magnetic resonance imaging (MRI) within 2 hours post-EVT and 24 hours after EVT. Association of infarct growth between 2 and 24 hours post-EVT and 24-hour National Institutes of Health Stroke Scale (NIHSS) as well as 90-day modified Rankin Scale score was assessed using multivariable logistic regression. RESULTS: Ninety-four of 155 (60.6%) patients achieved eTICI 2c/3 and were included in the analysis. Eighty of these 94 (85.1%) patients showed infarct growth between 2 and 24 hours post-reperfusion. Infarct growth ≥5 mL was seen in 39/94 (41.5%) patients, and infarct growth ≥10 mL was seen in 20/94 (21.3%) patients. Median infarct growth between 2 and 24 hours post-reperfusion was 4.5 mL (interquartile range: 0.4-9.2 mL). Post-reperfusion infarct growth was associated with the 24-hour NIHSS in multivariable analysis (odds ratio: 1.16 [95% confidence interval 1.09-1.24], P<0.01). CONCLUSION: Infarcts continue to grow after EVT, even if near-complete reperfusion is achieved. Investigating the underlying mechanisms may inform future therapeutic approaches for mitigating the process and help improve patient outcome.

How Do Quantitative Tissue Imaging Outcomes in Acute Ischemic Stroke Relate to Clinical Outcomes?

BACKGROUND AND PURPOSE: Infarct volume and other imaging markers are increasingly used as surrogate measures for clinical outcome in acute ischemic stroke research, but how improvements in these imaging surrogates translate into better clinical outcomes is currently unclear. We investigated how changes in infarct volume at 24 hours alter the probability of achieving good clinical outcome (modified Rankin Scale [mRS] 0-2). METHODS: Data are from endovascular thrombectomy patients from the randomized controlled ESCAPE-NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischaemic Stroke) trial. Infarct volume at 24 hours was manually segmented on non-contrast computed tomography or diffusion-weighted magnetic resonance imaging. Probabilities of achieving good outcome based on infarct volume were obtained from a multivariable logistic regression model. The probability of good outcome was plotted against infarct volume using linear spline regression. RESULTS: A total of 1,099 patients were included in the analysis (median final infarct volume 24.9 mL [interquartile range: 6.6-92.2]). The relationship between total infarct volume and good outcome probability was nearly linear for infarct volumes between 0 mL and 250 mL. In this range, a 10% increase in the probability of achieving mRS 0-2 required a decrease in infarct volume of approximately 34.0 mL (95% confidence interval: -32.5 to -35.6). At infarct volumes above 250 mL, the probability of achieving mRS 0-2 probability was near zero. The relationships of tissue-specific infarct volumes and parenchymal hemorrhage volume generally showed similar patterns, although variability was high. CONCLUSION: There seems to be a near-linear association between total infarct volume and probability of achieving good outcome for infarcts up to 250 mL, whereas patients with infarct volumes greater than 250 mL are highly unlikely to have a favorable outcome.

Endovascular Treatment for Cerebral Venous Thrombosis: Applying Lessons Learned from Clinical Trials of Endovascular Treatment in Acute Arterial Ischemic Stroke.

BACKGROUND: Cerebral venous thrombosis (CVT) is a rare but severely disabling form of stroke. Acute treatment mainly consists of medical management, since there is no robust evidence suggesting the benefit of endovascular treatment for CVT. Given the relative lack of data to guide acute treatment decision-making, CVT treatment decisions are mostly made on a case-by-case basis. In some ways, the current status quo of endovascular treatment for CVT resembles the state of endovascular treatment for acute ischemic stroke before the wave of major positive large vessel occlusion endovascular treatment trials in 2015. SUMMARY: The current state of evidence with regard to endovascular CVT treatment is summarized, parallels to acute ischemic stroke are drawn, and it is discussed how the lessons learned from the evolution of acute ischemic stroke endovascular treatment (EVT) trials could be applied to designing a trial of endovascular treatment for CVT. The review ends by outlining possible scenarios for the future of endovascular CVT treatment. KEY MESSAGES: CVT is a serious disease, affecting young patients and their families, and harbors a considerable social and economic burden. Working toward high-level evidence for the best possible treatment strategy and exploring a possible role for EVT to improve outcomes in CVT needs to remain a high priority in stroke research.

Association between CT Perfusion Parameters and Hemorrhagic Transformation after Endovascular Treatment in Acute Ischemic Stroke: Results from the ESCAPE-NA1 Trial.

BACKGROUND AND PURPOSE: Hemorrhagic transformation can occur as a complication of endovascular treatment for acute ischemic stroke. This study aimed to determine whether ischemia depth as measured by admission CTP metrics can predict the development of hemorrhagic transformation at 24 hours. MATERIALS AND METHODS: Patients with baseline CTP and 24-hour follow-up imaging from the ESCAPE-NA1 trial were included. RAPID software was used to generate CTP volume maps for relative CBF, CBV, and time-to-maximum at different thresholds. Hemorrhage on 24-hour imaging was classified according to the Heidelberg system, and volumes were calculated. Univariable and multivariable regression analyses assessed the association between CTP lesion volumes and hemorrhage/hemorrhage subtypes. RESULTS: Among 408 patients with baseline CTP, 142 (35%) had hemorrhagic transformation at 24-hour follow-up, with 89 (63%) classified as hemorrhagic infarction (HI1/HI2), and 53 (37%), as parenchymal hematoma (PH1/PH2). Patients with HI or PH had larger volumes of low relative CBF and CBV at each threshold compared with those without hemorrhage. After we adjustied for baseline and treatment variables, only increased relative CBF <30% lesion volume was associated with any hemorrhage (adjusted OR, 1.14; 95% CI, 1.02-1.27 per 10 mL), as well as parenchymal hematoma (adjusted OR, 1.23; 95% CI, 1.06-1.43 per 10 mL). No significant associations were observed for hemorrhagic infarction. CONCLUSIONS: Larger "core" volumes of relative CBF <30% were associated with an increased risk of PH following endovascular treatment. This particular metric, in conjunction with other clinical and imaging variables, may, therefore, help estimate the risk of post-endovascular treatment hemorrhagic complications.

European Stroke Organisation (ESO) and European Society for Minimally Invasive Neurological Therapy (ESMINT) Guideline on Acute Management of Basilar Artery Occlusion.

The aim of the present European Stroke Organisation (ESO) guideline is to provide evidence-based recommendations on the acute management of patients with basilar artery occlusion (BAO). These guidelines were prepared following the Standard Operational Procedure of the ESO and according to the GRADE methodology.Although BAO accounts for only 1-2% of all strokes, it has very poor natural outcome. We identified 10 relevant clinical situations and formulated the corresponding Population Intervention Comparator Outcomes (PICO) questions, based on which a systematic literature search and review was performed. The working group consisted of 10 voting members (five representing ESO and five ESMINT) and three non-voting junior members. The certainty of evidence was generally very low. In many PICOs, available data were scarce or lacking, hence, we provided expert consensus statements.First, we compared intravenous thrombolysis (IVT) to no IVT, but specific BAO-related data do not exist. Yet, historically, IVT was standard of care for BAO patients who were also included (albeit in small numbers) in IVT trials. Non-randomised studies of IVT-only cohorts showed high proportion of favourable outcomes. Expert Consensus suggests using IVT up to 24 hours unless otherwise contraindicated. We further suggest IVT plus endovascular treatment (EVT) over direct EVT. EVT on top of best medical treatment (BMT) was compared to BMT alone within 6 and 6-24 hours from last seen well. In both time windows, we observed a different effect of treatment depending on a) the region where the patients were treated (Europe vs. Asia), b) on the proportion of IVT in the BMT arm, and c) on the initial stroke severity. In case of high proportion of IVT in the BMT group and in patients with NIHSS below 10, EVT plus BMT was not found better than BMT alone. Based on very low certainty of evidence, we suggest EVT+BMT over BMT alone (this is based on results of patients with at least 10 NIHSS points and a low proportion of IVT in BMT). For patients with an NIHSS below 10, we found no evidence to recommend EVT over BMT. In fact, BMT was non-significantly better and safer than EVT. Furthermore, we found a stronger treatment effect of EVT+BMT over BMT alone in proximal and middle locations of BAO compared to distal location. While recommendations for patients without extensive early ischaemic changes in the posterior fossa can, in general, follow those of other PICOs, we formulated an Expert Consensus Statement suggesting against reperfusion therapy in those with extensive bilateral and/or brainstem ischaemic changes. Another Expert Consensus suggests reperfusion therapy regardless of collateral scores. Based on limited evidence, we suggest direct aspiration over stent retriever as the first-line strategy of mechanical thrombectomy. As an Expert Consensus, we suggest rescue percutaneous transluminal angioplasty and/or stenting after a failed EVT procedure. Finally, based on very low certainty of evidence, we suggest add-on antithrombotic treatment during EVT or within 24 hours after EVT in patients with no concomitant IVT and in whom EVT was complicated (defined as failed or imminent re-occlusion, or need for additional stenting or angioplasty).

A systematic review of randomized controlled trials of endovascular therapy for stroke on mortality and disability.

BACKGROUND: Endovascular treatment (EVT) has become standard of care for patients with anterior circulation large vessel occlusion (LVO) stroke, with indications having recently expanded to late time-window and large ischemic core patients. There is conflicting evidence on whether EVT reduces mortality or only disability. We performed a meta-analysis of randomized controlled trials (RCTs) to assess the effect of EVT on mortality and severe disability. METHODS: We systematically searched PubMed, Web of Science, Scopus, and Embase on November 15, 2023, to identify phase 3 RCTs comparing EVT to best medical treatment (BMT) in patients with anterior circulation LVO stroke in a common effects meta-analysis. The primary outcome was mortality at 3 months. Secondary outcomes were moderately severe or severe disability (modified Rankin Scale (mRS) score 4-5) at 3 months. RESULTS: 18 studies comparing EVT to BMT were included, with a total of 4309 patients; 2159 that were treated with EVT, and 2150 treated with BMT. Mortality was significantly lower in the EVT group than in the BMT group (odds ratio (OR): 0.81, 95% CI: 0.70-0.94). Proportions of moderately severe or severe disability (OR: 0.55, 95% CI: 0.48-0.62) were also significantly lower in patients treated with EVT. CONCLUSIONS: This meta-analysis suggests that EVT reduces both mortality and moderately severe or severe disability in patients with anterior circulation LVO stroke.

What Is a Meaningful Difference When Using Infarct Volume as the Primary Outcome?: Results From the HERMES Database.

BACKGROUND: Ischemic stroke lesion volume at follow-up is an important surrogate outcome for acute stroke trials. We aimed to assess which differences in 48-hour lesion volume translate into meaningful clinical differences. METHODS: We used pooled data from 7 trials investigating the efficacy of endovascular treatment for anterior circulation large vessel occlusion in acute ischemic stroke. We assessed 48-hour lesion volume follow-up computed tomography or magnetic resonance imaging. The primary outcome was a good functional outcome, defined as modified Rankin Scale (mRS) scores of 0 to 2. We performed multivariable logistic regression to predict the probability of achieving mRS scores of 0 to 2 and determined the differences in 48-hour lesion volume that correspond to a change of 1%, 5%, and 10% in the adjusted probability of achieving mRS scores of 0 to 2. RESULTS: In total, 1665/1766 (94.2%) patients (median age, 68 [interquartile range, 57-76] years, 781 [46.9%] female) had information on follow-up ischemic lesion volume. Computed tomography was used for follow-up imaging in 83% of patients. The median 48-hour lesion volume was 41 (interquartile range, 14-120) mL. We observed a linear relationship between 48-hour lesion volume and mRS scores of 0 to 2 for adjusted probabilities between 65% and 20%/volumes <80 mL, although the curve sloped off for lower mRS scores of 0-2 probabilities/higher volumes. The median differences in 48-hour lesion volume associated with a 1%, 5%, and 10% increase in the probability of mRS scores of 0 to 2 for volumes <80 mL were 2 (interquartile range, 2-3), 10 (9-11), and 20 (18-23) mL, respectively. We found comparable associations when assessing computed tomography and magnetic resonance imaging separately. CONCLUSIONS: A difference of 2, 10, and 20 mL in 48-hour lesion volume, respectively, is associated with a 1%, 5%, and 10% absolute increase in the probability of achieving good functional outcome. These results can inform the design of future stroke trials that use 48-hour lesion volume as the primary outcome.

Influence of Infarct Morphology and Patterns on Cognitive Outcomes After Endovascular Thrombectomy.

BACKGROUND: To assess the association of qualitative and quantitative infarct characteristics and 3 cognitive outcome tests, namely the Montreal Cognitive Assessment (MOCA) for mild cognitive impairment, the Boston Naming Test for visual confrontation naming, and the Sunnybrook Neglect Assessment Procedure for neglect, in large vessel occlusion stroke. METHODS: Secondary observational cohort study using data from the randomized-controlled ESCAPE-NA1 trial (Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke), in which patients with large vessel occlusion undergoing endovascular treatment were randomized to receive either intravenous Nerinetide or placebo. MOCA, Sunnybrook Neglect Assessment Procedure, and 15-item Boston Naming Test were obtained at 90 days. Total infarct volume, gray matter, and white matter infarct volumes were manually measured on 24-hour follow-up imaging. Infarcts were also visually classified as either involving the gray matter only or both the gray and white matter and scattered versus territorial. Associations of infarct variables and cognitive outcomes were analyzed using multivariable ordinal or binary logistic regression models. RESULTS: Of 1105 patients enrolled in ESCAPE-NA1, 1026 patients with visible infarcts on 24-hour follow-up imaging were included. MOCA and Sunnybrook Neglect Assessment Procedure were available for 706 (68.8%) patients and the 15-item Boston Naming Test was available for 682 (66.5%) patients. Total infarct volume was associated with worse MOCA scores (adjusted common odds ratio per 10 mL increase, 1.05 [95% CI, 1.04-1.06]). After adjusting for baseline variables and total infarct volume, mixed gray and white matter involvement (versus gray matter-only adjusted common odds ratio, 1.92 [95% CI, 1.37-2.69]), white matter infarct volume (adjusted common odds ratio per 10 mL increase 1.36 [95% CI, 1.18-1.58]) and territorial (versus scattered) infarct pattern (adjusted common odds ratio, 1.65 [95% CI, 1.15-2.38]) were associated with worse MOCA scores. Results for Sunnybrook Neglect Assessment Procedure and 15-item Boston Naming Test were similar, except for the territorial infarct pattern, which did not reach statistical significance in multivariable analysis. CONCLUSIONS: Besides total infarct volume, infarcts that involve the white matter and that show a territorial distribution were associated with worse cognitive outcomes, even after adjusting for total infarct volume.

Cost-Effectiveness of Late Endovascular Thrombectomy vs. Best Medical Management in a Clinical Trial Setting and Real-World Setting.

BACKGROUND AND PURPOSE: To assess cost-effectiveness of late time-window endovascular treatment (EVT) in a clinical trial setting and a "real-world" setting. METHODS: Data are from the randomized ESCAPE trial and a prospective cohort study (ESCAPE-LATE). Anterior circulation large vessel occlusion patients presenting > 6 hours from last-known-well were included, whereby collateral status was an inclusion criterion for ESCAPE but not ESCAPE-LATE. A Markov state transition model was built to estimate lifetime costs and quality-adjusted life-years (QALYs) for EVT in addition to best medical care vs. best medical care only in a clinical trial setting (comparing ESCAPE-EVT to ESCAPE control arm patients) and a "real-world" setting (comparing ESCAPE-LATE to ESCAPE control arm patients). We performed an unadjusted analysis, using 90-day modified Rankin Scale(mRS) scores as model input and analysis adjusted for baseline factors. Acceptability of EVT was calculated using upper/lower willingness-to-pay thresholds of 100,000 USD/50,000 USD/QALY. RESULTS: Two-hundred and forty-nine patients were included (ESCAPE-LATE:n = 200, ESCAPE EVT-arm:n = 29, ESCAPE control-arm:n = 20). Late EVT in addition to best medical care was cost effective in the unadjusted analysis both in the clinical trial and real-world setting, with acceptability 96.6%-99.0%. After adjusting for differences in baseline variables between the groups, late EVT was marginally cost effective in the clinical trial setting (acceptability:49.9%-61.6%), but not the "real-world" setting (acceptability:32.9%-42.6%). CONCLUSION: EVT for LVO-patients presenting beyond 6 hours was cost effective in the clinical trial setting and "real-world" setting, although this was largely related to baseline patient differences favoring the "real-world" EVT group. After adjusting for these, EVT benefit was reduced in the trial setting, and absent in the real-world setting.

Simulation of transportation of acute stroke patients in border regions.

Determining the optimal transportation for each stroke patient is critically important to achieve the best possible outcomes. In border regions the next comprehensive stroke center may be just across an international border, but bureaucratic and financial hurdles may prevent a simple transfer to the next stroke center. We hypothesized that in regions close to international borders, patients may benefit from an "open border, closed transfer scenario", meaning that patients in whom a large vessel occlusion (LVO) is detected in the primary stroke center will benefit from a transfer to the nearest stroke center offering endovascular thrombectomy-even if this may be across a national border. We used the Swiss-German-French trinational region as an example for a region with several international borders within close proximity to one another, and compared two feasible scenarios; (a) a "closed borders, open transfer" scenario, where the patient is transported to any center in the same country, (b) an "open border, closed transfer" scenario, where patients are always transported to the nearby primary stroke center first and then to the nearest comprehensive stroke center in either the same or a neighboring country and (c) and "open borders, open transfer" scenario. The outcome of interest was the predicted probability of acute ischemic stroke patients to achieve a good outcome using a conditional probability model which predicts the likelihood of excellent outcome (modified Rankin scale score of 0-1 at 90 days post-stroke) for patients with suspected LVO. Results were modeled in a virtual map from which the ideal transport concept emerged. For an exemplary LVO stroke patient in Germany, the probability of a good outcome was higher in an open border, closed transfer scenario than with closed borders, open transfer (33.1 vs. 30.1%). Moreover, time to EVT would decrease from 232 min in the first scenario to 169 min in an open border, closed transfer scenario. The catchment area of the University Hospital Basel was almost double the size in an open border, closed transfer scenario compared to closed borders (1674 km2 vs. 2897 km2) and would receive transfers from 3 primary stroke centers in other countries (2 in Germany and 1 in France). Stroke patients showed a higher likelihood of good outcome in the "open border" scenarios without transfer restrictions to a specific healthcare system. This probably has implications for stroke treatment in all border regions where EVT eligible stroke patients may benefit from transport to the closest EVT capable center whenever possible, regardless of whether this hospital is located in the same or a neighboring country/jurisdiction.

Mediation of Age and Thrombectomy Outcome by Neuroimaging Markers of Frailty in Patients With Stroke.

Importance: Age is a leading predictor of poor outcomes after brain injuries like stroke. The extent to which age is associated with preexisting burdens of brain changes, visible on neuroimaging but rarely considered in acute decision-making or trials, is unknown. Objectives: To explore the mediation of age on functional outcome by neuroimaging markers of frailty (hereinafter neuroimaging frailty) in patients with acute ischemic stroke receiving endovascular thrombectomy (EVT). Design, Setting, and Participants: This cohort study was a post hoc analysis of the Safety and Efficacy of Nerinetide (NA-1) in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) randomized clinical trial, which investigated intravenous (IV) nerinetide in patients who underwent EVT within a 12-hour treatment window. Patients from 48 acute care hospitals in 8 countries (Canada, US, Germany, Korea, Australia, Ireland, UK, and Sweden) were enrolled between March 1, 2017, and August 12, 2019. Markers of brain frailty (brain atrophy [subcortical or cortical], white matter disease [periventricular or deep], and the number of lacunes and chronic infarctions) were retrospectively assessed while reviewers were blinded to other imaging (eg, computed tomography angiography, computed tomography perfusion) or outcome variables. All analyses were done between December 1, 2022, and January 31, 2023. Exposures: All patients received EVT and were randomized to IV nerinetide (2.6 mg/kg of body weight) and alteplase (if indicated) treatment vs best medical management. Main Outcome and Measures: The primary outcome was the proportion of the total effect of age on 90-day outcome, mediated by neuroimaging frailty. A combined mediation was also examined by clinical features associated with frailty and neuroimaging markers (total frailty). Structural equation modeling was used to create latent variables as potential mediators, adjusting for baseline, early ischemic changes; stroke severity; onset-to-puncture time; nerinetide treatment; and alteplase treatment. Results: Among a total of 1105 patients enrolled in the study, 1102 (median age, 71 years [IQR, 61-80 years]; 554 [50.3%] male) had interpretable imaging at baseline. Of these participants, 549 (49.8%) were treated with IV nerinetide. The indirect effect of age on 90-day outcome, mediated by neuroimaging frailty, was associated with 85.1% of the total effect (ß coefficient, 0.04 per year [95% CI, 0.02-0.06 per year]; P < .001). When including both frailty constructs, the indirect pathway was associated with essentially 100% of the total effect (ß coefficient, 0.07 per year [95% CI, 0.03-0.10 per year]; P = .001). Conclusions and Relevance: In this cohort study, a secondary analysis of the ESCAPE-NA1 trial, most of the association between age and 90-day outcome was mediated by neuroimaging frailty, underscoring the importance of features like brain atrophy and small vessel disease, as opposed to chronological age alone, in predicting poststroke outcomes. Future trials could include such frailty features to stratify randomization or improve adjustment in outcome analyses.

Prevalence of "Ghost Infarct Core" after Endovascular Thrombectomy.

BACKGROUND AND PURPOSE: Baseline CTP sometimes overestimates the size of the infarct core ("ghost core" phenomenon). We investigated how often CTP overestimates infarct core compared with 24-hour imaging, and aimed to characterize the patient subgroup in whom a ghost core is most likely to occur. MATERIALS AND METHODS: Data are from the randomized controlled ESCAPE-NA1 trial, in which patients with acute ischemic stroke undergoing endovascular treatment were randomized to intravenous nerinetide or placebo. Patients with available baseline CTP and 24-hour follow-up imaging were included in the analysis. Ghost infarct core was defined as CTP core volume minus 24-hour infarct volume > 10 mL). Clinical characteristics of patients with versus without ghost core were compared. Associations of ghost core and clinical characteristics were assessed by using multivariable logistic regression. RESULTS: A total of 421 of 1105 patients (38.1%) were included in the analysis. Forty-seven (11.2%) had a ghost core > 10 mL, with a median ghost infarct volume of 13.4 mL (interquartile range 7.6-26.8). Young patient age, complete recanalization, short last known well to CT times, and possibly male sex were associated with ghost infarct core. CONCLUSIONS: CTP ghost core occurred in ∼1 of 10 patients, indicating that CTP frequently overestimates the infarct core size at baseline, particularly in young patients with complete recanalization and short ischemia duration.

Modeling diffusion-weighted imaging lesion expansion between 2 and 24 h after endovascular thrombectomy in acute ischemic stroke.

PURPOSE: Diffusion-weighted imaging (DWI) lesion expansion after endovascular thrombectomy (EVT) is not well characterized. We used serial diffusion-weighted magnetic resonance imaging (MRI) to measure lesion expansion between 2 and 24 h after EVT. METHODS: In this single-center observational analysis of patients with acute ischemic stroke due to large vessel occlusion, DWI was performed post-EVT (< 2 h after closure) and 24-h later. DWI lesion expansion was evaluated using multivariate generalized linear mixed modeling with various clinical moderators. RESULTS: We included 151 patients, of which 133 (88%) had DWI lesion expansion, defined as a positive change in lesion volume between 2 and 24 h. In an unadjusted analysis, median baseline DWI lesion volume immediately post-EVT was 15.0 mL (IQR: 6.6-36.8) and median DWI lesion volume 24 h post-EVT was 20.8 mL (IQR: 9.4-66.6), representing a median change of 6.1 mL (IQR: 1.5-17.7), or a 39% increase. There were no significant associations among univariable models of lesion expansion. Adjusted models of DWI lesion expansion demonstrated that relative lesion expansion (defined as final/initial DWI lesion volume) was consistent across eTICI scores (0-2a, 0.52%; 2b, 0.49%; 2c-3, 0.42%, p = 0.69). For every 1 mL increase in lesion volume, there was 2% odds of an increase in 90-day mRS (OR: 1.021, 95%CI [1.009, 1.034], p < 0.001). CONCLUSION: We observed substantial lesion expansion post-EVT whereby relative lesion expansion was consistent across eTICI categories, and greater absolute lesion expansion was associated with worse clinical outcome. Our findings suggest that alternate endpoints for cerebroprotectant trials may be feasible.

Endovascular Treatment of Medium Vessel Occlusion Stroke.

Approximately one-third of acute ischemic strokes with an identifiable vessel occlusion are caused by medium vessel occlusion (MeVO), that is, nonlarge vessel occlusions that are potentially amenable to endovascular treatment (EVT). Management of patients with MeVO is challenging in many ways: detecting MeVOs can be challenging, particularly for inexperienced physicians, and in busy clinical routine, MeVOs, therefore, remain sometimes undiagnosed. While the clinical course of MeVO stroke with medical management, including intravenous thrombolysis, is by no means, benign, it is more favorable compared with large vessel occlusion. At the same time, EVT complication rates are higher, and thus, the marginal benefit of EVT beyond best medical management is expected to be smaller and more challenging to detect if it were present. Several randomized controlled trials are currently underway to investigate whether and to what degree patients with MeVO may benefit from EVT and will soon provide robust data for evidence-based MeVO EVT decision-making. In this review, we discuss different ways of defining MeVOs, strategies to optimize MeVO detection on imaging, and considerations for EVT decision-making in the setting of MeVO stroke. We discuss the technical challenges related to MeVO EVT and conclude with an overview of currently ongoing MeVO EVT trials.