Strength of Association between Infarct Volume and Clinical Outcome Depends on the Magnitude of Infarct Size: Results from the ESCAPE-NA1 Trial

PACAP glycosides promote cell outgrowth in vitro and reduce infarct size after stroke in a preclinical model

Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) is a pleiotropic peptide known to promote many beneficial processes following neural damage and cell death after stroke. Despite PACAP's known neurotrophic and anti-inflammatory properties, it has not realized its translational potential due to a poor pharmacokinetic profile (non-linear PK/PD), and limited Blood-Brain Barrier Penetration (BBB) permeability. We have previously shown that glycosylation of PACAP increases stability and enhances BBB penetration. In addition, our prior studies showed reduced neuronal cell death and neuroinflammation in models of Parkinson's disease and Traumatic Brain Injury (TBI). In this study we show that a PACAP(1-27) glucoside retains the known neurotrophic activity of native PACAP(1-27)in vitro and a 5-day daily treatment regimen (100 nM) leads to neurite-like extensions in PC12 cells. In addition, we show that intraperitoneal injection of a PACAP(1-27) lactoside (10 mg/kg) with improved BBB-penetration, given 1-hour after reperfusion in a Transient Middle Cerebral Artery Occlusion (tMCAO) mouse model, reduces the infarct size after the ischemic injury in males significantly by ∼ 36 %, and the data suggest a dose-dependency. In conclusion, our data support further development of PACAP glycopeptides as promising novel drug candidates for the treatment of stroke, an area with an urgent clinical need.

Futile recanalization is associated with increased risk of post-stroke epilepsy

BACKGROUND

Endovascular treatment (EVT) is the standard of care of ischaemic stroke due to occlusion of large vessels. Although EVT can significantly improve short- and long-term outcomes, functional dependence can persist despite the achievement of a successful recanalization. The evidence about the predictors of post-stroke epilepsy (PSE) in patients with stroke treated by EVT is limited. We aimed to evaluate the relationship between futile recanalization and the risk of PSE.

METHODS

We retrospectively identified consecutive adults with first-ever ischaemic stroke of anterior circulation who were treated with EVT. Futile recanalization was defined as poor 3-month functional status (modified Rankin scale score ≥ 3) despite complete or near-complete recanalization. Study outcome was the occurrence of PSE during the follow-up.

RESULTS

The study included 327 patients with anterior circulation ischaemic stroke treated with EVT. Futile recanalization occurred in 116 (35.5%) patients and 26 (8.0%) developed PSE during a median follow-up of 35 [interquartile range, 22.7-55.2] months. Futile recanalization was more common among patients who developed PSE compared to those who did not (76.9% versus 31.9%; p < 0.001). Futile recanalization [hazard ratio (HR) = 5.63, 95% confidence interval (CI): 1.88-16.84; p = 0.002], large artery atherosclerosis (HR = 3.48, 95% CI: 1.44-8.40; p = 0.006), cortical involvement (HR = 15.51, 95% CI: 2.06-116.98; p = 0.008), and acute symptomatic status epilepticus (HR = 14.40, 95% CI: 2.80-73.98; p = 0.001) increased the risk of PSE.

CONCLUSIONS

Futile recanalization after EVT is associated with increased risk of PSE in patients with ischaemic stroke due to occlusion of large vessel of the anterior circulation.

Multimodal imaging evaluation of early neurological deterioration following acute ischemic stroke

Background

Early neurologic deterioration occurs in up to one-third of patients with acute ischemic stroke (IS), often leading to poor functional outcomes. At present, few studies have applied amide proton transfer (APT) imaging to the evaluation of early neurological deterioration (END). This study analyzed the value of computed tomography perfusion (CTP) combined with multimodal magnetic resonance imaging (MRI) in patients with acute IS with END.

Methods

This retrospective study included patients with acute IS who were admitted to the neurology inpatient department in a tertiary hospital from October 2021 to June 2023. Patients with acute IS underwent CTP within 24 hours of stroke onset and MRI [arterial spin labeling (ASL), susceptibility-weighted imaging (SWI), and APT] within 7 days. END was defined as an elevation of ≥2 points on the National Institute of Health Stroke Scale (NIHSS) within 7 days of stroke onset. Univariable and multivariable analyses were used to compare clinical and imaging biomarkers in patients with acute IS with and without END. The performance of potential biomarkers in distinguishing between the two groups was evaluated using receiver operating characteristic (ROC) curve analysis.

Results

Among the 70 patients with acute IS, 20 (29%) had END. After conducting univariable analysis, variables were selected for entry into a binary logistic regression analysis based on our univariable analysis results, previous research findings, clinical experience, and methodological standards. The results indicated that relative cerebral blood volume (CBV) on CTP, relative cerebral blood flow (CBF) on ASL, and relative signal intensity on amide proton transfer-weighted (APTw) imaging were independent risk factors for END. The areas under the ROC curves for these risk factors were 0.710 [95% confidence interval (CI): 0.559-0.861, P=0.006], 0.839 (95% CI: 0.744-0.933, P<0.001), and 0.804 (95% CI: 0.676-0.932, P<0.001), respectively. The combined area under the curve (AUC), sensitivity, and specificity of the four indices (0.941, 100%, and 78%, respectively) were higher than those of the four indices alone.

Conclusions

CTP combined with multi-modal MRI better evaluated hemodynamics, tissue metabolism, and other relevant patient information, providing an objective basis for the clinical assessment of patients with acute IS with END and facilitating the development of accurate and personalized treatment plans.

Unsuccessful Recanalization versus Medical Management of Patients with Large Ischemic Core : Analysis of the ANGEL-ASPECT Randomized Trial

PURPOSE

The outcomes of patients with large ischemic core who fail to recanalize with endovascular therapy (EVT) compared to medical management (MM) are uncertain. The objective was to evaluate the clinical and safety outcomes of patients who underwent EVT in patients with large ischemic core and unsuccessful recanalization.

METHODS

This was a post hoc analysis of the ANGEL-ASPECT randomized trial. Unsuccessful recanalization was defined as patients who underwent EVT with eTICI 0-2a. The primary endpoint was 90-day very poor outcome (mRS 5-6). Multivariable logistic regression was conducted controlling for ASPECTS, occlusion location, intravenous thrombolysis, and time to treatment.

RESULTS

Of 455 patients 225 were treated with MM. Of 230 treated with EVT, 43 (19%) patients had unsuccessful recanalization. There was no difference in 90-day very poor outcomes (39.5% vs. 40%, aOR 0.93, 95% confidence interval, CI 0.47-1.85, p = 0.95), sICH (7.0% vs. 2.7%, aOR 2.81, 95% CI 0.6-13.29, p = 0.19), or mortality (30% vs. 20%, aOR 1.65, 95% CI 0.89-3.06, p = 0.11) between the unsuccessful EVT and MM groups, respectively. There were higher rates of ICH (55.8% vs. 17.3%, p < 0.001), infarct core volume growth (142.7 ml vs. 90.5 ml, β = 47.77, 95% CI 20.97-74.57 ml, p < 0.001), and decompressive craniectomy (18.6% vs. 3.6%, p < 0.001) in the unsuccessful EVT versus MM groups.

CONCLUSION

In a randomized trial of patients with large ischemic core undergoing EVT with unsuccessful recanalization, there was no difference in very poor outcomes, sICH or death versus medically managed patients. In the unsuccessful EVT group, there were higher rates of any ICH, volume of infarct core growth, and decompressive craniectomy.

Endovascular thrombectomy versus intravenous thrombolysis for primary distal, medium vessel occlusion in acute ischemic stroke

Introduction

In the absence of clinical trials, the benefit of endovascular therapy (EVT) on the treatment of acute ischemic stroke (AIS) with primary distal and medium vessel occlusions (DMVO) is still not well defined. The aim of the study is to evaluate EVT with or without intravenous thrombolysis (EVT ± IVT) in primary DMVO stroke in comparison with a control cohort treated with IVT alone.

Methods

We analysed all consecutive AIS with proven primary DMVO. Primary endpoints were excellent outcome, functional independence at 3 months follow-up, and early neurologic improvement at 1 day after treatment.

Results

One hundred and fourteen patients with DMVO strokes were included between 2019 and 2023. Propensity-weighted analysis showed no significant differences in EVT ± IVT vs IVT for the excellent outcome (adjusted OR [aOR], 1.575; 95% CI, 0.706-3.513), functional independence (aOR, 2.024; 95% CI, 0.845-4.848), early neurological improvement (aOR, 2.218; 95% CI, 0.937-5.247), mortality (aOR, 0.498; 95% CI, 0.177-1.406), symptomatic intracranial haemorrhage (aOR, 0.493; 95% CI, 0.102-2.385), and subarachnoid haemorrhage (aOR, 0.560; 95% CI, 0.143-2.187). The type of revascularization did not influence the percentage of cerebral volume lost (adjusted linear regression estimate, -19.171, t value, 11.562; p = 0.104).

Conclusions

This study supports the hypothesis that patients with primary DMVO stroke treated with EVT (±IVT) or IVT alone have comparable outcomes.

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.

A Clinical and Imaging Fused Deep Learning Model Matches Expert Clinician Prediction of 90-Day Stroke Outcomes

BACKGROUND AND PURPOSE

Predicting long-term clinical outcome in acute ischemic stroke is beneficial for prognosis, clinical trial design, resource management, and patient expectations. This study used a deep learning-based predictive model (DLPD) to predict 90-day mRS outcomes and compared its predictions with those made by physicians.

MATERIALS AND METHODS

A previously developed DLPD that incorporated DWI and clinical data from the acute period was used to predict 90-day mRS outcomes in 80 consecutive patients with acute ischemic stroke from a single-center registry. We assessed the predictions of the model alongside those of 5 physicians (2 stroke neurologists and 3 neuroradiologists provided with the same imaging and clinical information). The primary analysis was the agreement between the ordinal mRS predictions of the model or physician and the ground truth using the Gwet Agreement Coefficient. We also evaluated the ability to identify unfavorable outcomes (mRS >2) using the area under the curve, sensitivity, and specificity. Noninferiority analyses were undertaken using limits of 0.1 for the Gwet Agreement Coefficient and 0.05 for the area under the curve analysis. The accuracy of prediction was also assessed using the mean absolute error for prediction, percentage of predictions ±1 categories away from the ground truth (±1 accuracy [ACC]), and percentage of exact predictions (ACC).

RESULTS

To predict the specific mRS score, the DLPD yielded a Gwet Agreement Coefficient score of 0.79 (95% CI, 0.71-0.86), surpassing the physicians' score of 0.76 (95% CI, 0.67-0.84), and was noninferior to the readers (P < .001). For identifying unfavorable outcome, the model achieved an area under the curve of 0.81 (95% CI, 0.72-0.89), again noninferior to the readers' area under the curve of 0.79 (95% CI, 0.69-0.87) (P < .005). The mean absolute error, ±1ACC, and ACC were 0.89, 81%, and 36% for the DLPD.

CONCLUSIONS

A deep learning method using acute clinical and imaging data for long-term functional outcome prediction in patients with acute ischemic stroke, the DLPD, was noninferior to that of clinical readers.

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.

Severely Hypoperfused Brain Tissue Correlates with Final Infarct Volume Despite Recanalization in DMVO Stroke

Objectives

We sought to assess whether there were any parameter(s) on baseline computed-tomography-perfusion (CTP) strongly correlating with final-infarct-volume, and infarct volume progression after endovascular recanalization of acute ischemic stroke (AIS) with primary distal, medium vessel occlusion (DMVO).

Materials and Methods

We performed a retrospective analysis of consecutive AIS patients who were successfully recanalized by thrombectomy for DMVO. By comparing baseline CTP and follow-up MRI, we evaluated the correlation between baseline infarct and hypoperfusion volumes, and final infarct volume and infarct volume progression. We also examined their effect on good clinical outcome at 3 months (defined as an mRS score of 0 to 2).

Results

Between January 2018 and January 2021, 38 patients met the inclusion criteria (76% [29/38] female, median age 75 [66-86] years). Median final infarct volume and infarct volume progression were 8.4 mL [IQR: 5.2-44.4] and 7.2 mL [IQR: 4.3-29.1] respectively. TMax > 10 sec volume was strongly correlated with both (r = 0.831 and r = 0.771 respectively, p < 0.0001), as well as with good clinical outcome (-0.5, p = 0.001). A higher baseline TMax > 10 sec volume increased the probability of a higher final-infarct-volume (r2 = 0.690, coefficient = 0.83 [0.64-1.00], p < 0.0001), whereas it decreased the probability of good clinical outcome at 3 months (odds ratio = -0.67 [-1.17 to -0.18], p = 0.008).

Conclusion

TMax > 10 sec volume on baseline CTP correlates strongly with final infarct volume as well as with clinical outcome after mechanical thrombectomy for an AIS with DMVO.

Breaking with a dogma: persisting diffusion restrictions (pDWI) in follow-up after endovascular treatment for stroke

BACKGROUND

Post-stroke diffusion weighted imaging (DWI) signal transformation of the infarct core, which results in high apparent diffusion coefficient (ADC) values and variable DWI signal intensity, is completed no later than 1 month after onset of ischemia. We observed frequent exceptions to this timeline of change in DWI signal, which led to uncertainties in further clinical patient management.

METHODS

A prospective single-center study of patients treated with mechanical thrombectomy of a large vessel occlusion in the anterior circulation was conducted. Patients received high-resolution MRI at 3T, including DWI, in the acute post-stroke phase and in the follow-up after 3-12 months.

RESULTS

Overall, 78 patients (45 men) of mean age 63.6 years were evaluated. We identified persisting or new diffusion restriction in 29 of the 78 patients (37.2%) on follow-up imaging. Diffusion restrictions in a different location from the infarct core, representing new (sub-)acute ischemia, were observed in four patients (5.1%). Smaller areas of persisting diffusion restriction (pDWI lesions with high DWI signal and reduced ADC values) within the former infarct core were observed in 25 patients (32.1%) without clinical evidence of recurrent stroke, but with worse outcome scores at follow-up compared with patients without pDWI lesions. The presence of pDWI lesions is associated with a large primary infarct core (multivariate regression OR 1.03 (95% CI 1.01 to 1.05); p<0.01), mediating the relationship between pDWI lesions and clinical outcome.

CONCLUSION

Smaller foci of persisting diffusion restriction (pDWI lesions) in the follow-up after endovascular treatment for stroke are frequent and likely represent a slowed ADC signal progression within a formerly large infarct core.

FLAIR vascular hyperintensity combined with asymmetrical prominent veins in acute anterior circulation ischemic stroke: prediction of collateral circulation and clinical outcome

BACKGROUND

To investigate the value of fluid-attenuated inversion recovery vascular hyperintensity (FVH) within asymmetrical prominent veins sign (APVS) on susceptibility-weighted imaging predicting collateral circulation and prognosis in patients with acute anterior circulation ischemic stroke.

METHOD

Patients with severe stenosis or occlusion of ICA or MCA M1, who underwent MRI within 72 h from stroke onset were reviewed. The Alberta Stroke Program Early CT Score was used to evaluate the volume of infarction on DWI, the degree of FVH and APVS. Spearman correlation analysis was used to evaluate the correlation between FVH and APVS. All patients were divided into the good prognosis group and the poor prognosis group according to the score of the modified ranking scale (mRS) 90 days after the stroke. Logistic regression analysis was used to explore the relationship between FVH and APVS and functional prognosis, while receiver operating characteristic (ROC) curves were plotted to assess the value of FVH and APVS in predicting prognosis.

RESULTS

Spearman correlation analysis revealed moderate positive correlations between FVH and APVS (r = 0.586, P < 0.001). The poor prognosis group had a higher rate of a history of atrial fibrillation, a larger cerebral infarction volume, a higher NIHSS score at admission, and a higher FVH and APVS score compared with the good prognosis group (all P < 0.05). A further logistic regression indicated that the NIHSS score, cerebral infarction volume, FVH and APVS were independent risk factors for a poor functional prognosis. In terms of FVH, APVS, alone and their combination for the diagnosis of poor prognosis, the sensitivity, specificity, area under the ROC curve (AUC), and 95% confidence interval (CI) were 86.8%, 83.3%, 0.899 (95% CI 0.830-0.968); 60.5%, 93.7%, 0.818 (95% CI 0.723-0.912); 86.8%, 89.6%, 0.921 (95% CI 0.860-0.981), respectively.

CONCLUSION

The presence of FVH and APVS can provide a comprehensive assessment of collateral circulation from the perspective of veins and arteries, and the correlation between the two is positively correlated. Both of them were independent risk factors for poor prognosis, their combination is complementary and can improve the predictive value.

Combining clinical and imaging data for predicting functional outcomes after acute ischemic stroke: an automated machine learning approach

This study aimed to develop and validate an automated machine learning (ML) system that predicts 3-month functional outcomes in acute ischemic stroke (AIS) patients by combining clinical and neuroimaging features. Functional outcomes were categorized as unfavorable (modified Rankin Scale ≥ 3) or not. A clinical model employing optimal clinical features (Model_A), a convolutional neural network model incorporating imaging data (Model_B), and an integrated model combining both imaging and clinical features (Model_C) were developed and tested to predict unfavorable outcomes. The developed models were compared with each other and with traditional risk-scoring models. The dataset comprised 4147 patients from a multicenter stroke registry, with 1268 (30.6%) experiencing unfavorable outcomes. Age, initial NIHSS, and early neurologic deterioration were identified as the most important clinical features. The ML model prediction achieved an area under the curves of 0.757 (95% CI 0.726-0.789) for Model_A, 0.725 (95% CI 0.693-0.755) for Model_B, and 0.786 (95% CI 0.757-0.814) for Model_C in the test set. The integrated models outperformed traditional risk-scoring models by 0.21 (95% CI 0.16-0.25) for HIAT and 0.15 (95% CI 0.11-0.19) for THRIVE. In conclusion, the integrated ML system enhanced stroke outcome prediction by combining imaging data and clinical features, outperforming traditional risk-scoring models.

Functional Outcome Prediction in Acute Ischemic Stroke Using a Fused Imaging and Clinical Deep Learning Model

BACKGROUND

Predicting long-term clinical outcome based on the early acute ischemic stroke information is valuable for prognostication, resource management, clinical trials, and patient expectations. Current methods require subjective decisions about which imaging features to assess and may require time-consuming postprocessing. This study's goal was to predict ordinal 90-day modified Rankin Scale (mRS) score in acute ischemic stroke patients by fusing a Deep Learning model of diffusion-weighted imaging images and clinical information from the acute period.

METHODS

A total of 640 acute ischemic stroke patients who underwent magnetic resonance imaging within 1 to 7 days poststroke and had 90-day mRS follow-up data were randomly divided into 70% (n=448) for model training, 15% (n=96) for validation, and 15% (n=96) for internal testing. Additionally, external testing on a cohort from Lausanne University Hospital (n=280) was performed to further evaluate model generalization. Accuracy for ordinal mRS, accuracy within ±1 mRS category, mean absolute prediction error, and determination of unfavorable outcome (mRS score >2) were evaluated for clinical only, imaging only, and 2 fused clinical-imaging models.

RESULTS

The fused models demonstrated superior performance in predicting ordinal mRS score and unfavorable outcome in both internal and external test cohorts when compared with the clinical and imaging models. For the internal test cohort, the top fused model had the highest area under the curve of 0.92 for unfavorable outcome prediction and the lowest mean absolute error (0.96 [95% CI, 0.77-1.16]), with the highest proportion of mRS score predictions within ±1 category (79% [95% CI, 71%-88%]). On the external Lausanne University Hospital cohort, the best fused model had an area under the curve of 0.90 for unfavorable outcome prediction and outperformed other models with an mean absolute error of 0.90 (95% CI, 0.79-1.01), and the highest percentage of mRS score predictions within ±1 category (83% [95% CI, 78%-87%]).

CONCLUSIONS

A Deep Learning-based imaging model fused with clinical variables can be used to predict 90-day stroke outcome with reduced subjectivity and user burden.

From therapeutic nihilism to armamentarium: A meta-analysis of randomized clinical trials assessing safety and efficacy of endovascular therapy for acute large ischemic strokes

BACKGROUND

Three recent randomized clinical trials (RCTs) investigated the potential benefit of endovascular therapy (EVT) in acute ischemic stroke patients presenting with large infarcts. We aimed to confirm the safety and efficacy of EVT in patients presenting with large infarcts and provide more precise estimations of the treatment effects using study-level meta-analysis.

METHODS

Comprehensive search of MEDLINE database through PubMed till February 2023 was performed including RCTs only. The data were then extracted from the selected studies and pooled as risk ratio (RR) with 95% confidence interval (95% CI).

RESULTS

There were a total of 1005 patients across the three qualifying RCTs. Regarding the functional outcomes assessed by modified Rankin Scale (mRS) score, the analyzed data demonstrated statistically significant differences in favor of thrombectomy for both independent ambulatory status (mRS 0-3: RR = 1.78, 95% CI [1.28, 2.48], p = 0.0006) and functional independence (mRS 0-2: RR = 2.54, 95% CI [1.85, 3.48], p < 0.001). The analyzed data did not demonstrate any statistically significant differences between EVT and medical management alone in terms of 90-day mortality (RR = 0.95, 95% CI [0.78, 1.16], p = 0.61), symptomatic intracranial hemorrhage (RR = 1.83, 95% CI [0.95, 3.55], p = 0.07), and need for hemicraniectomy (RR = 1.22, 95% CI [0.43, 3.41], p = 0.71).

CONCLUSION

This study confirms the benefit of EVT on functional outcomes of patients presenting with large ischemic infarcts without significant differences in the rates of symptomatic intracranial hemorrhage, hemicraniectomy, or 90-day mortality.

Radiomics Analysis of Diffusion-Weighted Imaging and Long-Term Unfavorable Outcomes Risk for Acute Stroke

BACKGROUND

Diffusion-weighted imaging radiomics could be used as prognostic biomarkers in acute ischemic stroke. We aimed to identify a clinical and diffusion-weighted imaging radiomics model for individual unfavorable outcomes risk assessment in acute ischemic stroke.

METHODS

A total of 1716 patients with acute ischemic stroke from 2 centers were divided into a training cohort and a validation cohort. Patient outcomes were measured with the modified Rankin Scale score. An unfavorable outcome was defined as a modified Rankin Scale score greater than 2. The primary end point was all-cause mortality or outcomes 1 year after stroke. The MRI-DRAGON score was calculated based on previous publications. We extracted and selected the infarct features on diffusion-weighted imaging to construct a radiomic signature. The clinic-radiomics signature was built by measuring the Cox proportional risk regression score (CrrScore) and compared with the MRI-DRAGON score and the ClinicScore. CrrScore model performance was estimated by 1-year unfavorable outcomes prediction.

RESULTS

A high radiomic signature predicted a higher probability of unfavorable outcomes than a low radiomic signature in the training (hazard ratio, 3.19 [95% CI, 2.51-4.05]; P<0.0001) and validation (hazard ratio, 3.25 [95% CI, 2.20-4.80]; P<0.0001) cohorts. The diffusion-weighted imaging Alberta Stroke Program Early CT Score, age, glucose level before therapy, National Institutes of Health Stroke Scale score on admission, glycated hemoglobin' radiomic signature, hemorrhagic infarction, and malignant cerebral edema were associated with an unfavorable outcomes risk after multivariable adjustment. A CrrScore nomogram was developed to predict outcomes and had the best performance in the training (area under the curve, 0.862) and validation cohorts (area under the curve, 0.858). The CrrScore model time-dependent areas under the curve of the probability of unfavorable outcomes at 1 year in the training and validation cohorts were 0.811 and 0.801, respectively.

CONCLUSIONS

The CrrScore model allows the accurate prediction of patients with acute ischemic stroke outcomes and can potentially guide rehabilitation therapies for patients with different risks of unfavorable outcomes.

Optimizing intraluminal monofilament model of ischemic stroke in middle-aged Sprague-Dawley rats

Intraluminal monofilament model of middle cerebral artery occlusion (MCAO) is widely adopted for ischemic stroke; and Sprague-Dawley (SD) rats are commonly used rodents for preclinical research. Due to the paucity of information on the appropriate monofilament size for inducing MCAO in SD rats and the importance of including middle-aged models in ischemic stroke studies, we aimed to: (i). determine an appropriate Doccol^® monofilament size for middle-aged male SD rats which weighed > 500 g following 24-h transient MCAO survival as well as (ii). demonstrate the optimal Doccol^® filament size for middle-aged males (≤ 500 g) and females (273-300 g) while using young adult male SD rats (372-472 g) as control for severity of infarct volume following 7-days post-MCAO. All rats were subjected to 90-min transient MCAO. We show that 0.43 mm Doccol^® monofilament size is more appropriate to induce large infarct lesion and optimal functional deficit when compared to 0.45 mm and 0.47 mm at 24 h post-MCAO. Our data on infarct volumes at 7 days post-MCAO as well as the observed weight loss and functional deficits at post-MCAO days 1, 3 and 7 demonstrate that 0.41 mm, 0.37 mm and 0.39 mm are optimal Doccol^® filament sizes for middle-aged male (477.3 ± 39.61 g) and female (302.6 ± 26.28 g) as well as young-adult male (362.2 ± 28.38 g) SD rats, respectively.

Deep profiling of multiple ischemic lesions in a large, multi-center cohort: Frequency, spatial distribution, and associations to clinical characteristics

Background purpose

A substantial number of patients with acute ischemic stroke (AIS) experience multiple acute lesions (MAL). We here aimed to scrutinize MAL in a large radiologically deep-phenotyped cohort.

Materials and methods

Analyses relied upon imaging and clinical data from the international MRI-GENIE study. Imaging data comprised both Fluid-attenuated inversion recovery (FLAIR) for white matter hyperintensity (WMH) burden estimation and diffusion-weighted imaging (DWI) sequences for the assessment of acute stroke lesions. The initial step featured the systematic evaluation of occurrences of MAL within one and several vascular supply territories. Associations between MAL and important imaging and clinical characteristics were subsequently determined. The interaction effect between single and multiple lesion status and lesion volume was estimated by means of Bayesian hierarchical regression modeling for both stroke severity and functional outcome.

Results

We analyzed 2,466 patients (age = 63.4 ± 14.8, 39% women), 49.7% of which presented with a single lesion. Another 37.4% experienced MAL in a single vascular territory, while 12.9% featured lesions in multiple vascular territories. Within most territories, MAL occurred as frequently as single lesions (ratio ∼1:1). Only the brainstem region comprised fewer patients with MAL (ratio 1:4). Patients with MAL presented with a significantly higher lesion volume and acute NIHSS (7.7 vs. 1.7 ml and 4 vs. 3, p FDR < 0.001). In contrast, patients with a single lesion were characterized by a significantly higher WMH burden (6.1 vs. 5.3 ml, p FDR = 0.048). Functional outcome did not differ significantly between patients with single versus multiple lesions. Bayesian analyses suggested that the association between lesion volume and stroke severity between single and multiple lesions was the same in case of anterior circulation stroke. In case of posterior circulation stroke, lesion volume was linked to a higher NIHSS only among those with MAL.

Conclusion

Multiple lesions, especially those within one vascular territory, occurred more frequently than previously reported. Overall, multiple lesions were distinctly linked to a higher acute stroke severity, a higher total DWI lesion volume and a lower WMH lesion volume. In posterior circulation stroke, lesion volume was linked to a higher stroke severity in multiple lesions only.

Prognostic value of post-treatment fluid-attenuated inversion recovery vascular hyperintensity in ischemic stroke after endovascular thrombectomy

OBJECTIVES

To explore the value of post-treatment fluid-attenuated inversion recovery vascular hyperintensity (FVH) in predicting clinical outcome in patients with acute ischemic stroke (AIS) after endovascular thrombectomy (EVT).

METHODS

This retrospective study reviewed data from consecutive patients with large vessel occlusion of anterior circulation between July 2017 and February 2021. Together with other variables, status of post-treatment FVH was assessed for each patient. Good outcome was defined as a 3-month modified Rankin Scale score of 0-2. Chi-square test, Fisher's exact test, independent-samples t test, multivariate logistic regression analysis, and receiver operating characteristic analysis were used as appropriate.

RESULTS

Among 84 included patients, 48 (57.1%) patients showed post-treatment FVH. Post-treatment FVH significantly correlated with incomplete recanalization (p < 0.05) and low Alberta Stroke Project Early CT Changes Score on post-treatment diffusion-weighted imaging (p < 0.05). Higher incidence of hemorrhage transformation was observed in patients with post-treatment FVH than those without (27.1% vs. 16.7%); however, the difference did not reach significance (p = 0.259). Successful recanalization (odds ratio [OR], 0.024; 95% confidence interval [CI] 0.003-0.194; p < 0.05), lower National Institutes of Health Stroke Scale scores at admission (NIHSS_pre) (OR, 1.196; 95% CI, 1.017-1.406; p < 0.05), and no post-treatment FVH (OR, 74.690; 95% CI, 4.624-1206.421; p < 0.05) were found to be independent predictors of good outcomes. Combined models integrating all three independent predictors (recanalization+NIHSS_pre+post-treatment FVH) significantly outperformed the combined model without post-treatment FVH (recanalization+NIHSS_pre) in predicting clinical outcome (p = 0.004).

CONCLUSIONS

Post-treatment FVH may be an effective prognostic marker associated with clinical outcome in patients with AIS after EVT.

KEY POINTS

• Post-treatment FVH correlates with incomplete recanalization and higher infarct volume. • Post-treatment FVH is independently associated with an unfavorable outcome. • Post-treatment FVH may provide prognostic information in patients with AIS after EVT.

Differential Influence of the COVID-19 Pandemic on Mechanical Thrombectomy and Bridging Therapy for Acute Ischemic Stroke

Background

The coronavirus disease 2019 (COVID-19) pandemic is having a dramatic impact on acute stroke care. Its effects may accompany stroke care for a long time. We compared the treatment, short-term and long-term functional outcomes of patients with AIS from 2019 to 2020. Our objective was to evaluate the effect of COVID-19 epidemic on mechanical thrombectomy (MT) in patients in our hospital.

Methods

We collected information on subjects treated with MT in 2019–2020, including age, sex, time from the onset to arterial sheath insertion, time from the onset to recanalization, the rate of lung infection and hemorrhagic transformation, modified Rankin scale (mRS), NHISS, and ASPECTS.

Results

The number of patients with MT decreased significantly by 26.6% in 2020 (p = 0.025). The pretreatment ASPECTS score for 2020 was significantly higher than 2019 (p = 0.004). Besides, the patients were more likely to develop lung infection (65 vs. 54.1%, p = 0.042) and had a higher risk of hemorrhagic transformation (47.4% vs. 30.4%, p = 0.005) in 2019. The discharged mRS reflected the worse short-term functional prognosis of patients with MT in 2019 (66 vs. 44.9%, p = 0.046). In the subgroup analysis of bridging thrombolysis (BT), more patients with BT are expected to have a poor short-term functional prognosis in 2020, according to the discharged mRS (62.5 vs. 37.5%, p = 0.024). However, there was no difference in mRS at 180 days between the two groups (p = 0.094).

Conclusion

For patients with MT, both short- and long-term functional outcomes were not significantly affected due to the mild condition of patients admitted to hospital in 2020. For patients with BT, the COVID-19 pandemic has prolonged the green channel time of stroke, leading to a poor short-term functional prognosis of patients with stroke in the pandemic period. There was no difference in the effectiveness of direct MT and BT during the COVID-19 pandemic.

Prognostic Significance of Admission Glucose Combined with Hemoglobin A1c in Acute Ischemic Stroke Patients with Reperfusion Therapy

Background: Elevated admission glucose and hemoglobin A1c (HbA1c) levels have been suggested to be associated with 90-day functional outcomes in acute ischemic stroke (AIS) patients with endovascular thrombectomy (EVT). However, whether the prognostic significance of admission glucose and that of HbA1c have a joint effect on patients with intravascular thrombolysis (IVT) and/or EVT remains unclear. This study aimed to explore the association between admission glucose combined with HbA1c and outcomes in patients with reperfusion therapy. Methods: Consecutive AIS patients treated with IVT and/or EVT between 2 January 2018 and 27 February 2021 in West China hospital were enrolled. Admission glucose and HbA1c levels were measured at admission. Participants were divided into four groups according to admission glucose level (categorical variable: <7.8 and ≥7.8 mmol/L) and HbA1c level (categorical variable: <6.5% and ≥6.5%): normal glucose and normal HbA1c (NGNA), normal glucose and high HbA1c (NGHA), high glucose and normal HbA1c (HGNA), and high glucose and high HbA1c (HGHA). The primary outcome was an unfavorable functional outcome defined as a modified Rankin Scale (mRS) ≥ 3. The secondary outcome was all-cause mortality at 90 days. Results: A total of 519 patients (mean age, 69.0 ± 13.4 years; 53.8% males) were included. Patients in the HGHA group had a significantly increased risk of unfavorable functional outcome (OR, 1.81; 95%CI, 1.01–3.23) and mortality (OR, 1.75; 95%CI, 1.01–3.06) at 90 days compared with those in the NGNA group after adjustment for confounders. There was no significant association between NGHA (OR, 0.43; 95%CI, 0.12–1.53) or HGNA (OR, 1.46; 95%CI, 0.84–2.56) and outcomes compared to the NGNA group. Conclusion: The combination of high admission glucose and high HbA1c level was significantly associated with unfavorable functional outcome and mortality at 90 days in AIS patients with reperfusion therapy.