Effect of Baseline CT Scan Appearance and Time to Recanalization on Clinical Outcomes in Endovascular Thrombectomy of Acute Ischemic Strokes

Automatic prediction of stroke treatment outcomes: latest advances and perspectives

Stroke is a major global health problem that causes mortality and morbidity. Predicting the outcomes of stroke intervention can facilitate clinical decision-making and improve patient care. Engaging and developing deep learning techniques can help to analyse large and diverse medical data, including brain scans, medical reports, and other sensor information, such as EEG, ECG, EMG, and so on. Despite the common data standardisation challenge within the medical image analysis domain, the future of deep learning in stroke outcome prediction lies in using multimodal information, including final infarct data, to achieve better prediction of long-term functional outcomes. This article provides a broad review of recent advances and applications of deep learning in the prediction of stroke outcomes, including (i) the data and models used, (ii) the prediction tasks and measures of success, (iii) the current challenges and limitations, and (iv) future directions and potential benefits. This comprehensive review aims to provide researchers, clinicians, and policy makers with an up-to-date understanding of this rapidly evolving and promising field.

Novel Risk Score to Predict Poor Outcome After Endovascular Treatment in Anterior Circulation Occlusive Acute Ischemic Stroke

BACKGROUND

We aimed to develop and validate a prognostic score to predict outcomes after endovascular treatment in acute ischemic stroke.

METHODS

The prognostic score was developed based on the ACTUAL (Endovascular Treatment for Acute Anterior Circulation Ischemic Stroke) registry. The validation cohort was derived from the Captor trial. Independent predictors of poor outcome after endovascular treatment were obtained from the least absolute shrinkage and selection operator regression and multivariable logistic regression. Corresponding regression coefficients were used to generate point scoring system. The area under the receiver operating characteristic curve and the Hosmer-Lemeshow goodness-of-fit test were used to assess model discrimination and calibration. The predictive properties of the developed prognostic score were validated and the discriminative power was compared with other validated tools.

RESULTS

A 17-point Age, Collateral Status, Blood glucose, Alberta Stroke Program Early Computed Tomography Score, and National Institutes of Health Stroke Scale score scale was developed from the set of independent predictors, including age, admission National Institutes of Health Stroke Scale score, Alberta Stroke Program Early Computed Tomography Score on initial computed tomography scan, blood glucose, and collateral status. The scale showed good discrimination in the derivation cohort (area under the receiver operating characteristic curve, 0.79 [95% CI, 0.75-0.82]) and validation cohorts (area under the receiver operating characteristic curve, 0.77 [95% CI, 0.70-0.84]). The scale was well calibrated (Hosmer-Lemeshow test) in the derivation cohort (P=0.57) and validation cohort (P=0.75).

CONCLUSIONS

The Age, Collateral Status, Blood glucose, Alberta Stroke Program Early Computed Tomography score, and National Institutes of Health Stroke Scale score scale is a valid tool for predicting outcomes and may be useful for endovascular stroke treatment in anterior circulation large vessel occlusions.

Assessment of collaterals on multiphase CTA in stroke patients with a large vessel occlusion: an interrater and intrarater agreement study

PURPOSE

The assessment of collateral circulation is an important prognostic factor in patients with stroke due to large vessel occlusion. The results of a recent trial suggested that collateral status could even be used for thrombectomy decision making in patients with late window acute ischemic stroke. However, the reliability of collateral assessment is uncertain. We sought to assess the interrater and intrarater agreement of collateral assessment using multiphase CT angiography.

METHODS

Two junior and two senior raters in stroke neurology, diagnostic neuroradiology, and interventional neuroradiology evaluated 60 multiphase CT scans of acute ischemic stroke and scored the presence of collaterals as follows: poor (< 50% collaterals), moderate (≥ 50% but < 100% collaterals), and good (100% collaterals), using the contralateral hemisphere for reference. Agreement was assessed through Fleiss kappa scoring for the global scale and for various dichotomizations.

RESULTS

The overall interrater agreement for the assessment of collaterals on Multiphase CTA was moderate, with higher agreement found among diagnostic neuroradiologists. Dichotomizing the agreement scale into "poor/moderate vs. good" and "poor vs. moderate/good" greatly increased the interrater agreement among all specialties, especially in the latter scenario. Similarly, global intrarater agreement of CTA collateral images was determined to be moderate to substantial, with improvement after dichotomization.

CONCLUSION

Interrater and intrarater agreement for the global collateral scale was modest, with improvement after dichotomization. Our work suggests that this scale can be reliably used in clinical practice after dichotomization.

Vertebrobasilar Artery Occlusion Treatment Outcomes Within 24 hours of Estimated Occlusion Time

BACKGROUND AND OBJECTIVES

The aim of this study was to investigate the efficacy and safety of endovascular treatment (EVT) in patients with acute vertebrobasilar artery occlusion (VBAO) within 24 hours of estimated occlusion time (EOT) and to evaluate the effect of early and late time window in a cohort of patients with VBAO treated with EVT.

METHODS

Retrospective analysis was conducted on patients within 24 hours of the EOT in 65 stroke centers in China. Favorable outcome was defined as modified Rankin Scale ≤3 at 90 days. Patients were divided into the medical management (MM) group and the EVT group. Times were dichotomized into early (EOT ≤6 hours) and late (>6 hours) time windows. Multivariate logical regression models were used to evaluate the efficacy and safety of EVT and the effect of time windows on outcomes in EVT patients.

RESULTS

Among 4124 patients, 2473 and 1651 patients were included in the early and late windows, respectively. 1702 patients received MM and 2422 were treated with EVT. EVT was associated with a higher rate of a favorable outcome at 90 days both in early (odds ratio [OR] 2.16, 95% CI 1.94-2.41) and late (OR 1.89, 95% CI 1.65-2.17) time windows. No differences were found regarding favorable outcome (OR 0.95, 95% CI 0.87-1.03) between VBAO patients treated with EVT within and beyond 6 hours.

CONCLUSION

Patients with acute VBAO who received EVT within 24 hours were associated with improved favorable outcome compared with patients who received MM. EVT beyond 6 hours is feasible and safe with no increase in symptomatic intracranial hemorrhage.

Endovascular treatment versus standard medical treatment in patients with established large infarct: a cohort study

BACKGROUND

Previous trials confirmed the benefit of endovascular treatment (EVT) in acute large core stroke, but the effect of EVT on outcomes in these patients based on noncontrast computed tomography (NCCT) in real-world clinical practice was unclear. The aim of this study was to explore the effect of EVT versus standard medical treatment (SMT) in patients with large ischemic core stroke defined as Alberta Stroke Program Early CT Score (ASPECTS) ≤5 based on NCCT alone.

MATERIALS AND METHODS

Patients with acute large core stroke at 38 Chinese centers between November 2021 and February 2023 were reviewed from a prospectively maintained database. The primary outcome was favorable functional outcome [modified Rankin Scale score (mRS), 0-3] at 90 days. Safety outcomes included 48 h symptomatic intracerebral hemorrhage (sICH) and 90-day mortality.

RESULTS

Of 745 eligible patients recruited at 38 stroke centers between November 2021 and February 2023, 490 were treated with EVT+SMT and 255 with SMT alone. One hundred and eighty-one (36.9%) in the EVT group achieved favorable functional independence versus 48 (18.8%) treated with SMT only [adjusted risk ratio (RR), 1.86; 95% CI: 1.43-2.42, P <0.001; adjusted risk difference (RD), 13.77; 95% CI: 7.40-20.15, P <0.001]. The proportion of sICH was significantly higher in patients undergoing EVT (13.3 vs. 2.4%; adjusted RR, 5.17; 95% CI: 2.17-12.32, P <0.001; adjusted RD, 10.10; 95% CI: 6.12-14.09, P <0.001). No significant difference of mortality between the groups was observed (41.8 vs. 49.0%; adjusted RR, 0.91; 95% CI: 0.77-1.07, P =0.24; adjusted RD, -5.91; 95% CI: -12.91-1.09, P =0.1).

CONCLUSION

Among patients with acute large core stroke based on NCCT in real-world, EVT is associated with better functional outcomes at 90 days despite of higher risk of sICH. Rates of procedure-related complications were relatively higher in the EVT+SMT group.

Efficacy analysis of mechanical thrombectomy combined with prolonged mild hypothermia in the treatment of acute middle cerebral artery occlusion: a single-center retrospective cohort study

Objective

To determine the efficacy of mechanical thrombectomy combined with prolonged mild hypothermia compared with conventional treatment in managing acute middle cerebral artery occlusion, and to explore whether extending the duration of hypothermia can improve neurological function.

Method

From 2018 to June 2023, a retrospective analysis was conducted on 45 patients with acute middle cerebral artery occlusion treated at the NICU of Suzhou Kowloon Hospital, affiliated with Shanghai Jiao Tong University School of Medicine. After thrombectomy, patients were admitted to the neurological intensive care unit (NICU) for targeted temperature management. Patients were divided into two groups: the mild hypothermia group (34.5-35.9°C) receiving 5-7 days of treatment, and the normothermia group (control group) whose body temperature was kept between 36 and 37.5°C using pharmacological and physical cooling methods. Baseline characteristics and temperature changes were compared between the two groups of patients. The primary outcome was the modified Rankin Scale (mRS) score at 3 month after surgery, and the secondary outcomes were related complications and mortality rate. Prognostic risk factors were investigated using both univariate and multivariate logistic regression analyses.

Results

Among 45 patients, 21 underwent prolonged mild hypothermia, and 24 received normothermia, with no significant differences in baseline characteristics between the two groups. The duration of mild hypothermia ranged from 5 to 7 days. The incidence of chills (33.3% vs. 8.3%, p = 0.031) and constipation (57.1% vs. 20.8%, p = 0.028) was significantly higher in the mild hypothermia group compared with the control group. There was no significant difference in mortality rates between the mild hypothermia and the control group (4.76% vs. 8.33%, p = 1.000, OR = 1.75, 95% CI, 0.171-17.949). At 3 month, there was no significant difference in the modified mRS (0-3) score between the mild hypothermia and control groups (52.4% vs. 25%, p = 0.114, OR = 0.477, 95% CI, 0.214-1.066). Infarct core volume was an independent risk factor for adverse neurological outcomes.

Conclusion

Prolonged mild hypothermia following mechanical thrombectomy had no severe complications and shows a trend to improve the prognosis of neurological function. The Infarct core volume on CTP was an independent risk factor for predicting neurological function.

Evaluation of the Ischemic Penumbra and Prognosis in acute Cerebral Infarction Using Cerebral Blood Flow and Delay Time Derived from Multi-delay pCASL Imaging

PURPOSE

The purpose of this study was to evaluate the ischemic penumbra and prognosis in acute cerebral infarction using cerebral blood flow (CBF) and delay time (DT) derived from multi-delay pseudo-continuous arterial spin-labeling (pCASL) imaging and to estimate the possible use of such indices to predict prognosis.

METHOD

Our subjects comprised 25 patients who were diagnosed with cerebral infarction in our stroke center between September 2017 and December 2018 and underwent pCASL perfusion MRI. The time from onset to MRI was 0.6 to 20 h (mean, 6 h) and was less than 4.5 h in 16 patients. Twelve patients received conservative treatment, three were treated with tPA, and the remaining 10 patients underwent invasive treatment (e.g., thrombectomy). They were subdivided by recanalization:18 patients were non-recanalized and 7 were recanalized. We evaluated the mean cerebral blood flow (CBF) and mean arterial transit DT at the infarct core and penumbra and the infarct size at the initial and follow-up examinations and calculated the infarct enlargement ratio (ER) from the initial and final infarct sizes. We also assessed clinical prognosis by using the initial and final NIHSS scores. We investigated the relationship among the ASL, ER, and NIHSS parameters and determined predictors of infarct enlargement using logistic analysis.

RESULT

The degree of the CBF decrease was related to the size of the initial infarct lesion (CBF at core:r=-0.4060, p=0.044;CBF at penumbra:r=-0.4970, p=0.012) and initial NIHSS (r=-0.451, p=0.024;CBF at penumbra:r=-0.491, p=0.013). Because no parameters were correlated with the ER in all patients. Specifically in the non-recanalization group, the DT at the penumbra was positively correlated with the ER (r=-0.496, p=0.034). Moreover, by logistic regression analysis, the DT at the penumbra was the only independent predictor of infarct enlargement in all patients (p=0.047) and in non-recanalization patients (p=0.036).

CONCLUSION

The only parameter predicting the ER was the mean DT at the penumbra, and the tendency was affected by recanalization status. DT obtained by multi-delay ASL may become a prognostic index of acute cerebral infarction. J. Med. Invest. 71 : 286-292, August, 2024.

Post-ASPECTS and Post-PC-ASPECTS Predict the Outcome of Anterior and Posterior Ischemic Stroke Following Thrombectomy

PURPOSE

In this study, we aimed to determine whether post-Alberta Stroke Project Early CT Changes Score (post-ASPECTS) in anterior stroke and post-(posterior circulation) PC-ASPECTS in posterior stroke on CT can predict post-endovascular thrombectomy (EVT) functional outcomes among patients with acute ischemic stroke (AIS) after EVT.

PATIENTS AND METHODS

A total of 247 consecutive patients aged 18 and over receiving EVT for LVO-related AIS were recruited into a prospective database. The data was retrospectively analyzed between March 2019 and February 2022 from two comprehensive tertiary care stroke centers: Foshan Sanshui District People's Hospital and First People's Hospital of Foshan in China. Patient parameters included EVT within 24 hr of symptom onset, premorbid modified Rankin scale (mRS) ≤2, presence of distal and terminal cerebral blood vessel occlusion, and subsequent 24-72-hr post-stroke onset CT scan. Univariate comparisons were performed using the Fisher's exact test or χ2 test for categorical variables and the Mann-Whitney U-test for continuous variables. Logistic regression analysis was performed to further analyze for adjusting for confounding factors. A p-value of ≤0.05 was statistically significant.

RESULTS

Overall, 236 individuals with 196 anterior circulation ischemic strokes and 40 posterior strokes of basilar artery occlusion were examined. Post-ASPECTS in anterior stroke and post-pc-ASPECTS as strong positive markers of favorable outcome at 90 days post-EVT; and lower rates of inpatient mortality/hospice discharge, 90-day mortality, and 90-day poor outcome were observed. Moreover, patients in the post-ASPECTS ≥ 7 cohort experienced shorter door-to-recanalization time (DRT), puncture-to-recanalization time (PRT), and last known normal-to-puncture time (LKNPT).

CONCLUSION

Post-ASPECTS ≥7 in anterior circulation AIS and post-pc-ASPECTS ≥7 in posterior circulation can serve as strong prognostic markers of functional outcome after EVT.

Clinical value of automated volumetric quantification of early ischemic tissue changes on non-contrast CT

BACKGROUND

Quantitative and automated volumetric evaluation of early ischemic changes on non-contrast CT (NCCT) has recently been proposed as a new tool to improve prognostic performance in patients undergoing endovascular therapy (EVT) for acute ischemic stroke (AIS). We aimed to test its clinical value compared with the Alberta Stroke Program Early CT Score (ASPECTS) in a large single-institutional patient cohort.

METHODS

A total of 1103 patients with AIS due to large vessel occlusion in the M1 or proximal M2 segments who underwent NCCT and EVT between January 2013 and November 2019 were retrospectively enrolled. Acute ischemic volumes (AIV) and ASPECTS were generated from the baseline NCCT through e-ASPECTS (Brainomix). Correlations were tested using Spearman's coefficient. The predictive capabilities of AIV for a favorable outcome (modified Rankin Scale score at 90 days ≤2) were tested using multivariable logistic regression as well as machine-learning models. Performance of the models was assessed using receiver operating characteristic (ROC) curves and differences were tested using DeLong's test.

RESULTS

Patients with a favorable outcome had a significantly lower AIV (median 12.0 mL (IQR 5.7-21.7) vs 18.8 mL (IQR 9.4-33.9), p<0.001). AIV was highly correlated with ASPECTS (rho=0.78, p<0.001) and weakly correlated with the National Institutes of Health Stroke Scale score at baseline (rho=0.22, p<0.001), and was an independent predictor of an unfavorable clinical outcome (adjusted OR 0.97, 95% CI 0.96 to 0.98). No significant difference was found between machine-learning models using either AIV or ASPECTS or both metrics for predicting a good clinical outcome (p>0.05).

CONCLUSION

AIV is an independent predictor of clinical outcome and presented a non-inferior performance compared with ASPECTS, without clear advantages for prognostic modelling.

Understanding ASPECTS of stroke: Inter-rater reliability between emergency medicine physician and radiologist in a rural setup

PURPOSE

The purpose is to determine the inter-rater reliability in grading ASPECTS score, between emergency medicine physician at first contact and radiologist among patients with acute ischemic stroke.

MATERIALS AND METHODS

We conducted a prospective analysis of 765 acute ischemic stroke cases referred to the Department of Radiodiagnosis in a rural-based hospital in South India, during January 2017 to October 2021. Non-contrast computed tomography (NCCT) scans of the brain were performed using GE Bright Speed Elite 128 Slice CT Scanner. ASPECTS score was calculated separately by an emergency medicine physician and radiologist. Inter-rater reliability for total and dichotomized ASPECTS (≥6 and <6) scores were assessed using statistical analysis (ICC and Cohen ĸ coefficients) on SPSS software (v17.0).

RESULTS

Inter-rater agreement for total and dichotomized ASPECTS was substantial (ICC 0.79 and Cohen ĸ 0.68) between the emergency physician and the radiologist. Mean difference in ASPECTS between the two readers was only 0.15 with standard deviation of 1.58. No proportionality bias was detected. The Bland-Altman plot was constructed to demonstrate the distribution of ASPECTS differences between the two readers.

CONCLUSION

Substantial inter-rater agreement was noted in grading ASPECTS between emergency medicine physician at first contact and radiologist, thereby confirming its robustness even in a rural setting.

Predictive Value of Different Computed Tomography Perfusion Software Regarding 90-Day Outcome of Acute Ischemic Stroke Patients After Endovascular Treatment: A Comparison With Magnetic Resonance Imaging

OBJECTIVE

This study compared ischemic core and penumbra volumes obtained using different computed tomography perfusion (CTP) software and evaluated the predictive value of CTP and magnetic resonance imaging (MRI) results for 90-day outcomes.

METHODS

In total, 105 acute ischemic stroke patients who underwent endovascular treatment from January 2016 to December 2020 were included. Patients were divided into good and poor outcome groups by a modified Rankin Scale score. Computed tomography perfusion core and penumbra volumes were obtained using OleaSphere and Vitrea software to assess the volumetric relationship with MRI using the Spearman correlation test, intraclass correlation coefficient (ICC), and Bland-Altman plot. Three multivariable models were developed: baseline variables with MRI infarct volume, baseline variables with OleaSphere core volume, and baseline variables with Vitrea core volume. The area under the receiver operating characteristic curve of the 3 models was compared using the DeLong test.

RESULTS

Median core volumes were 27.5, 26.9, and 31.1 mL for OleaSphere, Vitrea, and MRI, respectively. There was substantial correlation and excellent agreement between OleaSphere and MRI core volume ( ρ = 0.84, P < 0.001; ICC = 0.84) and Vitrea and MRI core volume ( ρ = 0.80, P < 0.001; ICC = 0.83). The areas under curve for MRI volume, OleaSphere, and Vitrea were 0.86, 0.84, and 0.83, respectively. There were no significant differences ( P = 0.18) between the predictive value of the 3 models.

CONCLUSIONS

Computed tomography perfusion core volumes showed substantial correlation and excellent agreement with MRI. There was no significant difference in the predictive value of the 3 models, suggesting that core volumes measured using CTP software can predict patient prognosis.

The safety and effectiveness of endovascular treatment for patients with vertebrobasilar artery occlusions: according to the BEST and BASICS criteria

Background:

Whether endovascular treatment (EVT) is safe and effective for vertebrobasilar artery occlusion (VBAO) is yet incompletely understood. Two RCTs, the endovascular treatment versus standard medical treatment for vertebrobasilar artery occlusion (BEST) trail and the Basilar Artery International Cooperation Study (BASICS), concentrating on this field were recently reported.

Objective:

We use real-world registry data of VBAO to compare the outcome of EVT inside and outside the inclusion and exclusion criteria of the BEST and BASICS study to testify the feasibility of the selection paradigms of VBAO in these trials.

Methods:

Consecutive patients with VBAO receiving EVT involving 21 stroke centers were retrospectively included. The safety outcomes [3-month mortality, symptomatic intracranial hemorrhage (sICH), and effectiveness outcomes (the proportion of 3-month functional independence (mRS of 0–2) and favorable outcome (mRS of 0–3)] were compared between VBAO patients who meet or failed to meet the BEST/BASICS selection criteria for EVT.

Results:

Our study cohort consisted of 577 VBAO patients who underwent EVT. Of them, 446 patients had pc-ASPECTS ≧8. Successful reperfusion (mTICI 2b or 3) was achieved in 85.4% (n = 493). There were 418 patients fulfilling the BEST criterion for EVT and 194 fulfilling the BASICS criterion. Regression analysis indicated that adherence to BEST or BASICS criterion for EVT was not independently related to most of the safety and effectiveness outcome except that adherence to BEST was significantly associated with the 3-month favorable outcome (OR_BEST: 1.742, 95% CI: 1.087–2.790). However, when we put pc-ASPECTS into both criteria with a cut-off value of 8, meeting both BEST criterion plus pc-ASPECTS and BASICS criterion plus pc-ASPECTS was independently related to 3-month functional independence (OR_BEST: 1.687, 95% CI: 1.077–2.644; OR_BASIC: 1.653, 95% CI: 1.038–2.631) and favorable outcome (OR_BEST: 2.280, 95% CI: 1.484–3.502; OR_BASIC: 2.153, 95% CI: 1.372–3.378).

Conclusion:

Our study indicated that, based on real-world data of EVT, adherence to BEST or BASICS criterion for EVT was not independently associated with the safety and effectiveness outcome except that adherence to BEST was significantly related to the 3-month favorable outcome. However, the BEST or BASICS selection criterion and pc-ASPECTS ≧8 might be better paradigms for EVT patient selection.

Short-term Montreal Cognitive Assessment predicts functional outcome after endovascular therapy

Background

The previous studies have shown that cognition in patients 4–8 weeks after stroke can predict early functional outcomes after stroke. The analyses of data from the REVASCAT trial proved that stent thrombectomy improves post-morbid wiring test outcomes in patients with AIS compared with drug therapy. However, few studies focus on the relationship between cognitive impairment and functional outcomes in patients undergoing endovascular treatment.

Methods

A total of 647 participants registered from stroke centers. Stroke severity was evaluated by National Institutes of Health stroke scale (NIHSS). The functional status was estimated by modified Rankin scale (mRS). The cognitive impairment was assessed by trained neurologists at 14 (±4) and 90 (±7) days after stroke onset using the Montreal Cognitive Assessment (MoCA). A MoCA score of less than 26 was considered post-stroke cognitive impairment (PSCI).

Results

A total of 120 Patients who underwent endovascular therapy were included. The PSCI group had higher levels of age, men, educational status, atrial fibrillation, smoking, alcoholism, Alberta Stroke Program Early CT (ASPECT) score of the anterior circulation, and OTP time than the non-PSCI group (p < 0.05). In contrast, the 14-day MoCA score, 14-day NIHSS score, 3-month MoCA score, 3-month NIHSS score, 3-month mRS score, and 3-month EQ5D score were lower in those PSCI patients. The risk predictors of PSCI were age, sex, educational level, atrial fibrillation, smoking, alcoholism, ASPECT Score (anterior circulation), 14-day MoCA score, and 14-day NIHSS score. There were strong relationships between 3-month NIHSS and MoCA (r = –0.483, p < 0.001). Receiver operating characteristic (ROC) curve indicated that 14-day MoCA score, memory, abstraction, visuospatial/executive functions, attention, and language, played a significant role to predict PSCI [area under the curve (AUC) > 0.7]. It had predictive value for the 14-day visuospatial/executive functions to predict 3-month functional outcomes.

Conclusion

Early application of the MoCA in different cognitive regions could predict the PSCI and future functional outcomes, which is necessary to screen high-risk patients with poor prognosis and conduct an early intervention.

Combined Approach to Eptifibatide and Thrombectomy in Acute Ischemic Stroke Because of Large Vessel Occlusion: A Matched-Control Analysis

BACKGROUND

In patients undergoing mechanical thrombectomy (MT), adjunctive antithrombotic might improve angiographic reperfusion, reduce the risk of distal emboli and reocclusion but possibly expose patients to a higher intracranial hemorrhage risk. This study evaluated the safety and efficacy of combined MT plus eptifibatide for acute ischemic stroke.

METHODS

This was a propensity-matched analysis of data from 2 prospective trials in Chinese populations: the ANGEL-ACT trial (Endovascular Treatment Key Technique and Emergency Workflow Improvement of Acute Ischemic Stroke) in 111 hospitals between November 2017 and March 2019, and the EPOCH trial (Eptifibatide in Endovascular Treatment of Acute Ischemic Stroke) in 15 hospitals between April 2019 and March 2020. The primary efficacy outcome was good outcome (modified Rankin Scale score 0-2) at 3 months. Secondary efficacy outcomes included the distribution of 3-month modified Rankin Scale scores and poor outcome (modified Rankin Scale score 5-6) and successful recanalization. The safety outcomes included any intracranial hemorrhage, symptomatic intracranial hemorrhage, and 3-month mortality. Mixed-effects logistic regression models were used to account for within-hospital clustering in adjusted analyses.

RESULTS

Eighty-one combination arm EPOCH subjects were matched with 81 ANGEL-ACT noneptifibatide patients. Compared with the no eptifibatide group, the eptifibatide group had significantly higher rates of successful recanalization (91.3% versus 81.5%; P=0.043) and 3-month good outcomes (53.1% versus 33.3%; P=0.016). No significant difference was found in the remaining outcome measures between the 2 groups. All outcome measures of propensity score matching were consistent with mixed-effects logistic regression models in the total population.

CONCLUSIONS

This matched-control study demonstrated that MT combined with eptifibatide did not raise major safety concerns and showed a trend of better efficacy outcomes compared with MT alone. Overall, eptifibatide shows potential as a periprocedural adjunctive antithrombotic therapy when combined with MT. Further randomized controlled trials of MT plus eptifibatide should be prioritized.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03844594 (EPOCH), NCT03370939 (ANGEL-ACT).

Cost-Consequence Analysis of Advanced Imaging in Acute Ischemic Stroke Care

Introduction: The purpose of this study was to illustrate the potential costs and health consequences of implementing advanced CT angiography and perfusion (CTAP) as the initial imaging in patients presenting with acute ischemic stroke (AIS) symptoms at a comprehensive stroke center (CSC).

Methods: A decision-simulation model based on the American Heart Association's recommendations for AIS care pathways was developed to assess imaging strategies for a 5-year period from the institutional perspective. The following strategies were compared: (1) advanced CTAP imaging: NCCT + CTA + CT perfusion at the time of presentation; (2) standard-of-care: non-contrast CT (NCCT) at the time of presentation, with CT angiography (CTA) ± CT perfusion only in select patients (initial imaging to exclude hemorrhage and extensive ischemia) for mechanical thrombectomy (MT) evaluation. Model parameters were defined with evidence-based data. Cost-consequence and sensitivity analyses were performed. The modified Rankin Scale (mRS) at 90 days was used as the outcome measure.

Results: The decision-simulation modeling revealed that adoption of the advanced CTAP imaging increased per-patient imaging costs by 1.19% ($9.28/$779.72), increased per-patient treatment costs by 33.25% ($729.96/$2,195.24), and decreased other per-patient acute care costs by 0.7% (–$114.12/$16,285.85). The large increase in treatment costs was caused by higher proportion of patients being treated. However, improved outcomes lowered the other per-patient acute care costs. Over the five-year period, advanced CTAP imaging led to 1.63% (66/4,040) more patients with good outcomes (90-day mRS 0-2), 2.23% (66/2,960) fewer patients with poor outcomes (90-day mRS 3-5), and no change in mortality (90-day mRS 6). Our CT equipment utilization analysis showed that the demand for CT equipment in terms of scanner time (minutes) was 24% lower in the advanced CTAP imaging strategy compared to the standard-of-care strategy. The number of EVT procedures performed at the CSC may increase by 50%.

Conclusions: Our study reveals that adoption of advanced CTAP imaging at presentation increases the demand for treatment of acute ischemic stroke patients as more patients are diagnosed within the treatment time window compared to standard-of-care imaging. Advanced imaging also leads to more patients with good functional outcomes and fewer patients with dependent functional status.

Importance of computed tomography angiography in acute/hyperacute ischemic stroke

Objective

To evaluate the importance of computed tomography and computed tomography angiography (CTA) in stroke protocols, as well as their impact on endovascular treatment and on the determination of the etiology.

Materials and Methods

Were evaluated 28 patients with acute/hyperacute stroke in the anterior circulation who underwent intracranial and cervical CTA between April 2018 and August 2019. The parameters evaluated were the degree of stenosis, plaque characteristics, type of infarct, treatment, etiology, and the Alberta Stroke Program Early CT Score (ASPECTS).

Results

Of the 28 patients evaluated, 16 (57.1%) had an ASPECTS of 10 (the maximum score, indicative of normality). Four patients (14.3%) underwent thrombolytic treatment, and seven (25.0%) underwent mechanical thrombectomy. The etiology was atherosclerosis in 32.1% of the patients, cerebral small-vessel disease in 7.1%, cardioembolic in 7.1%, and undetermined in 53.6%. Regarding plaque, 17.9% of the patients presented stenosis ≥ 50%, 21.4% presented stable plaques, and 42.9% presented vulnerable plaques. Patients with a lower ASPECTS were more likely to have relevant stenosis and were more likely to have a total infarct.

Conclusion

In the evaluation of patients with acute/hyperacute strokes, CTA provides important information, identifying occlusion, as well as helping define the etiology and inform decisions regarding treatment.

NIHSS-the Alberta Stroke Program Early CT Score mismatch in guiding thrombolysis in patients with acute ischemic stroke

Objective

This study investigates the mismatch between the National Institutes of Health Stroke Scale (NIHSS) score and the computed tomography (CT) findings measured by the Alberta Stroke Program Early CT Score (ASPECTS) for predicting the functional outcome and safety of intravenous thrombolysis (IVT) treatment in patients with acute ischemic stroke (AIS).

Methods

This prospective observational study includes patients with AIS who underwent CT imaging within 4.5 h of the onset of symptoms. Patients were divided into the NIHSS–ASPECTS mismatch (NAM)-positive and NAM-negative groups (group P and N, respectively). The clinical outcome was assessed using the Modified Rankin Scale (mRS). Safety outcomes included progression, symptomatic intracerebral hemorrhage (sICH), intracerebral hemorrhage (ICH), adverse events, clinical adverse events, and mortality.

Results

A total of 208 patients were enrolled in the study. In group P, IVT treatment was associated with a good functional outcome at 3 months (p = 0.005) and 1 year (p = 0.001). A higher percentage of patients with favorable mRS (0–2) (p = 0.01) and excellent mRS (0–1) (p = 0.011) functional outcomes was obtained at 1 year in group P with IVT treatment. Group N did not benefit from the same treatment (p = 0.352 and p = 0.480 at 3 months and 1 year, respectively). There were no statistically significant differences in sICH, ICH, mortality rates, or other risks between the IVT and conventional treatment groups.

Conclusion

IVT treatment is associated with a good functional outcome in patients with NAM, without increasing the risks of sICH, ICH, mortality, or other negative outcomes. NAM promises to be an easily obtained indicator for guiding the treatment decisions of AIS.

ASPECT scores of patients with focal intracerebral hemorrhage were correlated with their short- and medium-term functional outcomes

PURPOSE

The Alberta Stroke Program Early CT Score (ASPECTS) is widely used to guide thrombolytic therapy and predict the functional outcome of patients with acute ischemic stroke (AIS). Whether ASPECTS can predict the functional outcome of patients with intracerebral hemorrhage (ASPECTS-H) remains unclear.

METHODS

Patients with primary intracerebral hemorrhage (ICH) were collected and retrospectively analyzed. ASPECTS-H was assessed at admission. Patients were followed up at 30 days and 90 days after the onset of ICH. Occurrence of death within 90 days after ICH was the primary endpoint. Modified Rankin Scale (mRS) ≥ 3 was considered a poor functional outcome.

RESULTS

A total of 149 patients met eligibility criteria; 61 (40.9%) had poor functional outcome at 30 days, and 37 (24.8%) had poor functional outcome at 90 days. Using binary logistic regression modeling, we found that a low ASPECTS-H was associated with a poor functional outcome. The risk ratio of a low ASPECTS-H was 2.31 at 30 days (P = 0.000; 95% CI, 1.560-3.421) and 2.711 at 90 days (P = 0.000; 95% CI, 1.677-4.381). The optimal cutoff value of ASPECTS-H to discriminate good and poor 30-day and 90-day outcomes was 7.5 (Sensitivity_30-day = 0.636, 1-Specificity_{30 - day} = 0.311; Sensitivity_90-day = 0.580, 1-Specificity_90-day = 0.270).

CONCLUSIONS

A low ASPECTS-H was an indicator of poor short-term and long-term functional outcomes of ICH.

Continuous Glibenclamide Prevents Hemorrhagic Transformation in a Rodent Model of Severe Ischemia-Reperfusion

BACKGROUND

Endovascular thrombectomy (EVT) is highly effective but may also lead to hemorrhagic transformation (HT) and edema, which may be more pronounced in severe ischemia. We sought to determine whether glibenclamide can attenuate HT and edema in a severe ischemia-reperfusion model that reflects EVT.

METHODS

Using a transient middle cerebral artery occlusion (tMCAo) rodent model of stroke, we studied two rat cohorts, one without rt-PA and a second cohort treated with rt-PA. Glibenclamide or vehicle control was administered as an intravenous bolus at reperfusion, followed by continuous subcutaneous administration with an osmotic pump.

RESULTS

Compared to vehicle control, glibenclamide improved neurological outcome (median 7, interquartile range [IQR 6-8] vs. control median 6 [IQR 0-6], p = 0.025), reduced stroke volume (323 ± 42 vs. 484 ± 60 mm3, p < 0.01), swelling volume (10 ± 4 vs. 28 ± 7%, p < 0.01) and water content (84 ± 1 vs. 85 ± 1%, p < 0.05). Glibenclamide administration also reduced HT based on ECASS criteria, densitometry (0.94 ± 0.1 vs. 1.15 ± 0.2, p < 0.01), and quantitative hemoglobin concentration (2.7 ± 1.5 vs. 6.2 ± 4.6 uL, p = 0.011). In the second cohort with rt-PA coadministration, concordant effects on HT were observed with glibenclamide.

CONCLUSIONS

Taken together, these studies demonstrated that glibenclamide reduced the amount of edema and HT after severe ischemia. This study suggests that co-administration of glibenclamide may be worth further study in severe stroke patients treated with EVT with or without IV rt-PA.

Endovascular stroke treatment after 6-24 hours only needs non-contrast CT

OBJECTIVES

Imaging selected patients with proximal anterior circulation stroke who demonstrate limited infarct may benefit from endovascular treatment beyond conventional time limits. Our aim was to evaluate the results of the EVT group series arriving between 6 and 24 hours from the onset of symptoms with (ASPECTS) ≥7 to our hospital (with 24/7 interventional neuroradiology) comparing them with those obtained in our prospectively registered series arriving between 0 and 6 hours.

MATERIALS AND METHODS

The inclusion criteria were ≥18 years, an interval between stroke and endovascular treatment of 6-24 hours, prestroke score mRS 0-2, no intracranial haemorrhage, (NIHSS) scale 8-22 and infarct evaluated by CT scan ≥7 in ASPECTS scale. Data, including patient demographics, neuroimaging findings, procedural details, recanalization rates and 90-day mRS, were collected.

RESULTS

Twelve of the 14 (85.71%) endovascular group patients who came to our centre between 6 and 24 hours had good outcomes at 90 days. To confirm our findings, we evaluated patients treated at our centre who met the selection criteria from January 2017 to September 2019. In this period, 382 patients with large vessel occlusion were treated endovascularly. 56 patients met all the criteria for inclusion and exclusion for our study. 31 of these 56 patients (56.36%) obtained a (mRS) scale ≤2 at three months. There was no significant difference (P = 0.063).

CONCLUSION

In circumstances of difficult access to MRI or CT perfusion, a computed tomography of ASPECTS ≥7 is sufficient to indicate endovascular treatment in a stroke of known onset between 6 and 24 hours.

ASPECTS Interobserver Agreement of 100 Investigators from the TENSION Study

Purpose

Evaluating the extent of cerebral ischemic infarction is essential for treatment decisions and assessment of possible complications in patients with acute ischemic stroke. Patients are often triaged according to image-based early signs of infarction, defined by Alberta Stroke Program Early CT Score (ASPECTS). Our aim was to evaluate interrater reliability in a large group of readers.

Methods

We retrospectively analyzed 100 investigators who independently evaluated 20 non-contrast computed tomography (NCCT) scans as part of their qualification program for the TENSION study. Test cases were chosen by four neuroradiologists who had previously scored NCCT scans with ASPECTS between 0 and 8 and high interrater agreement. Percent and interrater agreements were calculated for total ASPECTS, as well as for each ASPECTS region.

Results

Percent agreements for ASPECTS ratings was 28%, with interrater agreement of 0.13 (95% confidence interval, CI 0.09–0.16), at zero tolerance allowance and 66%, with interrater agreement of 0.32 (95% CI: 0.21–0.44), at tolerance allowance set by TENSION inclusion criteria. ASPECTS region with highest level of agreement was the insular cortex (percent agreement = 96%, interrater agreement = 0.96 (95% CI: 0.94–0.97)) and with lowest level of agreement the M3 region (percent agreement = 68%, interrater agreement = 0.39 [95% CI: 0.17–0.61]).

Conclusion

Interrater agreement reliability for total ASPECTS and study enrollment was relatively low but seems sufficient for practical application. Individual region analysis suggests that some are particularly difficult to evaluate, with varying levels of reliability. Potential impairment of the supraganglionic region must be examined carefully, particularly with respect to the decision whether or not to perform mechanical thrombectomy.

Endovascular Treatment Decision Making in Patients with Low Baseline ASPECTS: Insights from UNMASK EVT, an International Multidisciplinary Study

BACKGROUND

Current stroke treatment guidelines restrict level 1A recommendations for endovascular therapy to patients with baseline ASPECTS score > 5. However, a recent meta-analysis from the HERMES-group showed treatment benefit in patients with ASPECTS ≤ 5. We aimed to explore how physicians across different specialties and countries approach endovascular treatment decision-making in acute ischemic stroke patients with low baseline ASPECTS.

METHODS

In a multidisciplinary survey, 607 stroke physicians were randomly assigned 10 out of a pool of 22 case-scenarios, 3 of which involved patients with low baseline ASPECTS (A:40-year old with ASPECTS 4, B:33-year old with ASPECTS 2 C:72-year old with ASPECTS 3), otherwise fulfilling all EVT-eligibility criteria. Participants were asked how they would treat the patient A) under their current local resources and B) under assumed ideal conditions, without any external (monetary, policy-related or infrastructural) restraints. Overall and scenario-specific decision rates were calculated. Clustered multivariable logistic regression analysis was used to determine the association of baseline ASPECTS with endovascular treatment-decision.

RESULTS

Baseline ASPECTS score was significantly associated with current (OR:1.09, CI 1.05-1.13) and ideal endovascular treatment-decision (OR:1.12, CI 1.08-1.16). Overall current and ideal treatment decision-rates for the low ASPECTS scenarios were 57.1% and 57.6%. Current and ideal rates for the two younger patients were higher (scenario A:69.9/60.4%, scenario B:60.0/61.5%) compared to the 72-year old patient (41.3/40.2%).

CONCLUSION

Most physicians decided to proceed with endovascular treatment despite low baseline ASPECTS, particularly in younger patients. This may have implications on the design and execution of low ASPECTS randomized trials.

Combined Effect of Age and Baseline Alberta Stroke Program Early Computed Tomography Score on Post-Thrombectomy Clinical Outcomes in the MR CLEAN Registry

BACKGROUND AND PURPOSE

Ischemic brain tissue damage in patients with acute ischemic stroke, as measured by the Alberta Stroke Program Early CT Score (ASPECTS) may be more impactful in older than in younger patients, although this has not been studied. We aimed to investigate a possible interaction effect between age and ASPECTS on functional outcome in acute ischemic stroke patients undergoing endovascular treatment, and compared reperfusion benefit across age and ASPECTS subgroups.

METHODS

Patients with ischemic stroke from the MR CLEAN Registry (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; March 2014-November 2017) were included. Multivariable ordinal logistic regression was performed to obtain effect size estimates (adjusted common odds ratio) on functional outcome (modified Rankin Scale score) for continuous age and granular ASPECTS, with a 2-way multiplicative interaction term (age×ASPECTS). Outcomes in four patient subgroups based on age (< versus ≥ median age [71.8 years]) and baseline ASPECTS (6-10 versus 0-5) were assessed.

RESULTS

We included 3279 patients. There was no interaction between age and ASPECTS on modified Rankin Scale (P=0.925). The highest proportion of modified Rankin Scale 5 to 6 was observed in patients >71.8 years with baseline ASPECTS 0 to 5 (68/107, 63.6%). There was benefit of reperfusion in all age-ASPECTS subgroups. Although the adjusted common odds ratio was lower in patients >71.8 years with ASPECTS 0 to 5 (adjusted common odds ratio, 1.60 [95% CI, 0.66-3.88], n=110), there was no significant difference from the main effect (P=0.299).

CONCLUSIONS

Although the proportion of poor outcomes following endovascular treatment was highest in older patients with low baseline ASPECTS, outcomes did not significantly differ from the main effect. These results do not support withholding endovascular treatment based n a combination of high age and low ASPECTS.

Anemia Predicts Poor Clinical Outcome in Mechanical Thrombectomy Patients with Fair or Good Collateral Circulation

Background and Purpose

Anemia predicts poor clinical outcome of ischemic stroke in the general stroke population. We studied whether this applies to those treated with mechanical thrombectomy for proximal anterior circulation occlusion in the setting of differing collateral circulation.

Methods

We collected the data of 347 consecutive anterior circulation stroke patients who underwent mechanical thrombectomy after multimodal CT imaging in a single tertiary stroke care center. Patients with occlusion of the internal carotid artery and/or the first segment of the middle cerebral artery were included. We recorded baseline clinical, laboratory, procedural, and imaging variables, and the technical, imaging, and clinical outcomes. Differences between anemic and nonanemic patients were studied with appropriate statistical tests and binary logistic regression analysis.

Results

Ninety-four out of the 285 patients eligible for analysis had anemia, and 243 had fair or good collateral circulation (collateral score, CS, >0). Fifty-four percent of the patients experienced good 3-month clinical outcome (modified Rankin Scale ≤2). In pooled analyses of the CS 1–4 and 2–4 ranges, nonanemic patients had good clinical outcome significantly more often (p < 0.001 for both). This effect was not seen in patients with poor collateral circulation (CS = 0). Nonanemic patients had significantly better odds of good clinical outcome (OR = 2.6, 95% CI 1.377–5.030, p = 0.004) in a binary regression model. A 0.1 g/dL increase in hemoglobin improved the odds of good clinical outcome by 2% (OR = 1.02, 95% CI 1.002–1.044, p = 0.03).

Conclusions

Low hemoglobin on admission predicts poor clinical outcome in mechanical thrombectomy patients with fair or good collateral circulation.

Effect of age and baseline ASPECTS on outcomes in large-vessel occlusion stroke: results from the HERMES collaboration

BACKGROUND

Patient age and baseline Alberta Stroke Program Early CT score (ASPECTS) are both independent predictors of outcome in acute ischemic stroke patients treated with endovascular therapy (EVT). We assessed the combined effect of age and ASEPCTS on clinical outcome in acute ischemic stroke patients with LVO with and without EVT, and EVT treatment effect in different age/ASPECTS subgroups.

METHODS

The HERMES collaboration pooled data of seven randomized controlled trials that tested the efficacy of EVT. Adjusted logistic regression was performed to test for multiplicative interaction of age and ASPECTS with the primary outcome (ordinal mRS) and secondary outcomes (mRS 0-2/0-1/0-3) in the EVT and control arms. Patients were then stratified by age (<75 vs ≥ 75 years) and ASPECTS (0-5/6-7/8-10), and adjusted effect-size estimates for the association of EVT were derived for the six age/ASPECTS subgroups.

RESULTS

1735 patients were included in the analysis. There was no multiplicative interaction between age and ASPECTS on clinical outcomes. In the exploratory subgroup analysis, we found a nominally negative point estimate for the association of EVT with clinical outcome in the ASPECTS 0-5/age ≥75, subgroup (acOR 0.36, 95% CI 0.07 to 1.89). The point estimate for moderate outcome (mRS0-3) nominally favored EVT (aOR 1.24, 95% CI 0.16 to 9.84). In all other subgroups, effect size-estimates consistently favored EVT.

CONCLUSION

There was no multiplicative interaction of age and ASPECTS on clinical outcomes in EVT or control arm patients. Outcomes in patients ≥75 years with ASPECTS 0-5 were poor, irrespective of treatment. Further investigation to define the role of EVT and range of acceptable outcomes in this subgroup is warranted.

The Clinical Usefulness of Targeted Temperature Management in Acute Ischemic Stroke with Malignant Trait After Endovascular Thrombectomy

BACKGROUND/OBJECTIVE

Targeted temperature management (TTM) may be more beneficial after endovascular treatment (EVT) in patients with a large ischemic core. Therefore, we assessed the usefulness of TTM for such patients from a multicenter endovascular registry.

METHODS

Anterior circulation stroke patients who underwent endovascular recanalization were included; acute ischemic stroke with malignant traits was designated as (1) baseline Alberta Stroke Program Early CT Score (ASPECTS) below 6 and (2) diffusion-weighted imaging (DWI) lesion volume measurement (> 82 ml) or National Institutes of Health Stroke Scale score > 20 and item Ia > 0. TTM (34.5 °C) was maintained for at least 48 h.

RESULTS

We evaluated baseline demographics, risk factors, EVT parameters, and clinical outcomes between the TTM and non-TTM groups. Among the 548 patients, the TTM group (n = 91) significantly had a lower baseline ASPECTS (p < 0.001) and a higher DWI volume (p < 0.001) than the non-TTM group (n = 457). TTM group had a lower prevalence of favorable outcome (0-2 of modified Rankin Scale at 3 months; p = 0.008) than the non-TTM group. In a subgroup analysis of malignant trait patients (n = 80), TTM patients (n = 28) had more favorable outcome (32.1% vs. 7.7% p = 0.009) and less hemorrhagic transformation (none vs. any hemorrhage, p = 0.007) than non-TTM patients (n = 52). After adjusting for potential outcome predictors, TTM (odds ratio [OR] 4.63; confidence interval [CI] 1.20-17.89; p = 0.026) and hypertension (OR 0.18; CI 0.04-0.74; p = 0.018) were found to be independent determinants.

CONCLUSIONS

Our data suggest that TTM attenuates impending hemorrhagic transformation and leads to favorable clinical outcomes in EVT patients with malignant trait.

Impacts of in-hospital workflow on functional outcome in stroke patients treated with endovascular thrombectomy

High-performance in-hospital workflow may save time and improve the efficacy of thrombectomy in patients with acute ischemic stroke. However, the optimal in-hospital workflow is far from being formulated, and the current models varied distinctly among centers. This study aimed to evaluate the impacts of in-hospital workflow on functional outcomes after thrombectomy. Patients were enrolled from a multi-center registry program in China. Based on in-hospital managing procedure and personnel involved, two workflow models, neurologist-dominant and non-neurologist-dominant, were identified in the participating centers. Favorable outcome was defined as a mRS score of ≤ 2 at 90 days of stroke onset. After patients being matched with propensity score matching (PSM) method, ratios of favorable outcomes and symptomatic intracerebral hemorrhage (sICH) were compared between patients with different workflow models. Of the 632 enrolled patients, 543 (85.9%) were treated with neurologist-dominant and 89 (14.1%) with non-neurologist-dominant model. 88 patients with neurologist-dominant model and 88 patients with non-neurologist-dominant model were matched with PSM. For the matched patients, no significant differences concerning the ratios of successful recanalization (92.0% vs 87.5%, P = 0.45), sICH (17.0% vs 14.8%, P = 0.85), favorable outcome (42.0% vs 42.0%, P = 1.00) were detected between patients with neurologist-dominant model and those with non-neurologist-dominant model. Patients with neurologist-dominant model had shorter door to puncture time (124 (86-172) vs 156 (120-215), P = 0.005), fewer passes of retriever (2 (1-3) vs 2 (1-4), P = 0.04), lower rate of > 3 passes (11.4% vs 28.4%, P = 0.004), and lower incidence of asymptomatic intracerebral hemorrhage rate (27.3% vs 43.2%, P = 0.045). Although the neurologist-dominant model may decrease in-hospital delay and risk of asymptomatic intracerebral hemorrhage, workflow models may not influence the functional outcome significantly after thrombectomy in patients with acute ischemic stroke.

Predictors of poor clinical outcome despite complete reperfusion in acute ischemic stroke patients

BACKGROUND

In patients suffering from acute ischemic stroke from large vessel occlusion (LVO), mechanical thrombectomy (MT) often leads to successful reperfusion. Only approximately half of these patients have a favorable clinical outcome. Our aim was to determine the prognostic factors associated with poor clinical outcome following complete reperfusion.

METHODS

Patients treated with MT for LVO from a prospective single-center stroke registry between July 2015 and April 2019 were screened. Complete reperfusion was defined as Thrombolysis in Cerebral Infarction (TICI) grade 3. A modified Rankin scale at 90 days (mRS90) of 3-6 was defined as 'poor outcome'. A logistic regression analysis was performed with poor outcome as a dependent variable, and baseline clinical data, comorbidities, stroke severity, collateral status, and treatment information as independent variables.

RESULTS

123 patients with complete reperfusion (TICI 3) were included in this study. Poor clinical outcome was observed in 67 (54.5%) of these patients. Multivariable logistic regression analysis identified greater age (adjusted OR 1.10, 95% CI 1.04 to 1.17; p=0.001), higher admission National Institutes of Health Stroke Scale (NIHSS) (OR 1.14, 95% CI 1.02 to 1.28; p=0.024), and lower Alberta Stroke Program Early CT Score (ASPECTS) (OR 0.6, 95% CI 0.4 to 0.84; p=0.007) as independent predictors of poor outcome. Poor outcome was independent of collateral score.

CONCLUSION

Poor clinical outcome is observed in a large proportion of acute ischemic stroke patients treated with MT, despite complete reperfusion. In this study, futile recanalization was shown to occur independently of collateral status, but was associated with increasing age and stroke severity.

Deep Learning–Derived High-Level Neuroimaging Features Predict Clinical Outcomes for Large Vessel Occlusion

Background and Purpose—

For patients with large vessel occlusion, neuroimaging biomarkers that evaluate the changes in brain tissue are important for determining the indications for mechanical thrombectomy. In this study, we applied deep learning to derive imaging features from pretreatment diffusion-weighted image data and evaluated the ability of these features in predicting clinical outcomes for patients with large vessel occlusion.

Methods—

This multicenter retrospective study included patients with anterior circulation large vessel occlusion treated with mechanical thrombectomy between 2013 and 2018. We designed a 2-output deep learning model based on convolutional neural networks (the convolutional neural network model). This model employed encoder-decoder architecture for the ischemic lesion segmentation, which automatically extracted high-level feature maps in its middle layers, and used its information to predict the clinical outcome. Its performance was internally validated with 5-fold cross-validation, externally validated, and the results compared with those from the standard neuroimaging biomarkers Alberta Stroke Program Early CT Score and ischemic core volume. The prediction target was a good clinical outcome, defined as a modified Rankin Scale score at 90-day follow-up of 0 to 2.

Results—

The derivation cohort included 250 patients, and the validation cohort included 74 patients. The convolutional neural network model showed the highest area under the receiver operating characteristic curve: 0.81±0.06 compared with 0.63±0.05 and 0.64±0.05 for the Alberta Stroke Program Early CT Score and ischemic core volume models, respectively. In the external validation, the area under the curve for the convolutional neural network model was significantly superior to those for the other 2 models.

Conclusions—

Compared with the standard neuroimaging biomarkers, our deep learning model derived a greater amount of prognostic information from pretreatment neuroimaging data. Although a confirmatory prospective evaluation is needed, the high-level imaging features derived by deep learning may offer an effective prognostic imaging biomarker.

Risk Stratification for Endovascular Treatment in Acute Anterior Circulation Occlusive Stroke

OBJECTIVE

To develop and validate a novel scoring system for risk stratification in acute anterior circulation large vessel occlusion stroke patients undergoing endovascular treatment.

METHODS

Subjects were included from a multicenter registry on acute ischemic stroke undergoing thrombectomy in China. Two thirds of the patients were used as the derivation group and the other one third of the patients as the validation group. Multivariable logistic regression was used to generate the scoring system. The area under the receiver operating characteristic curve and Hosmer-Lemeshow goodness-of-fit test were used to assess model discrimination and calibration, respectively.

RESULTS

The Risk strAtification for eNdovascular treatment in acute anterior circulation occlusive stroKe (RANK) scale (total score ranges from -11 to 14) showed good discrimination in the derivation cohort (AUC = .79; 95% confidence interval [CI], .74-.84) and validation cohorts (AUC = .74; 95% CI, .68-.81), as well as good calibration (Hosmer-Lemeshow test) in the validation cohort (P = .54). We categorized the RANK score into 5 predictive groups for an unfavorable functional outcome, less than or equal to -8 (very low risk), -7 to -4 (low risk), -3 to 0 (intermediate), 1-5 (high risk), and greater than or equal to 6 (very high risk). In the very high risk group, only 3.3% (1 of 30, 95% CI: .08%-.2%) of patients in the derivation group and 5.5% (1 of 18, 95% CI: .1%-.3%) of patients in the validation group achieved a good functional outcome at day 90.

CONCLUSIONS

The novel scale is a valid tool for risk stratification for endovascular stroke treatment in anterior circulation large vessel occlusions.

Application of FLAIR Vascular Hyperintensity-DWI Mismatch in Ischemic Stroke Depending on Semi-Quantitative DWI-Alberta Stroke Program Early CT Score

Objective: Diffusion-weighted imaging (DWI)-Alberta Stroke Program Early CT Score (ASPECTS) is a simple, widely used method to estimate the size of the infarct. Our aim is to determine whether there is a relationship between DWI-ASPECTS and fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH)-DWI mismatch and to better quantify FVH-DWI mismatch to assess the prognosis of cerebral infarction. Materials and Methods: A retrospective analysis of 109 patients with MCA stenosis or occlusion with cerebral infarction was performed by dividing this cohort into FVH-DWI match group and FVH-DWI mismatch group based on FVH and DWI results. The clinical and imaging data of these two groups of patients were reviewed and analyzed to identify associations between FVH-DWI mismatch and prognosis of patients for preservation of neurological function. Correlation between DWI-ASPECTS and FVH-DWI mismatch was also performed. Results: FVH-DWI mismatch was present in 66/109 (60.55%) patients, and FVH-DWI match was present in 43/109 (39.45%). Patients with FVH-DWI mismatch had higher DWI-ASPECTS (7.0 vs. 4.0, P < 0.001) and lower mRS at 3 months (3.0 vs. 4.0, P < 0.001) than patients without FVH-DWI mismatch. Multiple regression analysis suggested that DWI-ASPECTS (OR = 4.7, 95% CI = 2.5-9.2, P < 0.001) remained significantly associated with FVH-DWI mismatch. Two threshold points for DWI-ASPECTS of 3 and 8 can be used to distinguish whether there is a mismatch in FVH-DWI by smooth curve fitting. Conclusions: The DWI-ASPECTS score was an independent predictor of FVH-DWI mismatch. At DWI-ASPECTS ≤ 3, the FVH-DWI mismatch offers no prognostic value; whereas, at DWI-ASPECTS ≥ 8, the FVH-DWI mismatch had the highest prognostic value. DWI-ASPECTS can roughly determine whether there is a FVH-DWI mismatch in order to select optimal clinical treatment and accurately assess prognosis.

Alberta Stroke Program Early CT Score Versus Computed Tomographic Perfusion to Predict Functional Outcome After Successful Reperfusion in Acute Ischemic Stroke

Background and Purpose- We aimed to compare the ability of conventional Alberta Stroke Program Early CT Score (ASPECTS), automated ASPECTS, and ischemic core volume on computed tomographic perfusion to predict clinical outcome in ischemic stroke because of large vessel occlusion ≤18 hours after symptom onset. Methods- We selected patients with acute ischemic stroke from the CRISP study (Computed Tomographic Perfusion to Predict Response to Recanalization in Ischemic Stroke Project) with successful reperfusion (modified treatment in cerebral ischemia score 2b or 3). We used e-ASPECTS software to calculate automated ASPECTS and RAPID software to estimate ischemic core volumes. We studied associations between these imaging characteristics and good outcome (modified Rankin Scale score, 0-2) or poor outcome (modified Rankin Scale score, 4-6) in univariable and multivariable analysis, after adjustment for relevant clinical confounders. Results- We included 156 patients. Conventional and automated ASPECTS was not associated with good or poor outcome in univariable analysis ( P=nonsignificant for all). Automated ASPECTS was associated with good outcome in multivariable analysis ( P=0.02) but not with poor outcome. Ischemic core volume was associated with good ( P<0.01) and poor outcome ( P=0.04) in univariable and multivariable analysis ( P=0.03 and P=0.02, respectively). Computed tomographic perfusion predicted good outcome with an area under the curve of 0.62 (95% CI, 0.53-0.71) and optimal cutoff core volume of 15 mL. Conclusions- Ischemic core volume assessed on computed tomographic perfusion is a predictor of clinical outcome among patients in whom endovascular reperfusion is achieved ≤18 hours after symptom onset. In this population, conventional or automated ASPECTS did not predict outcome.

Current concepts in imaging and endovascular treatment of acute ischemic stroke: implications for the clinician

During the last decade, the management of acute ischemic stroke has changed dramatically, from an expectant bedside "wait and see" attitude towards active treatment, thanks to the continuous improvement of new therapeutic options. In addition to the use of intravenous (IV) thrombolysis in emergent large vessel occlusion (ELVO), endovascular therapy (EVT) has proven to be very efficient in selected acute stroke patients. The indications for EVT have progressed from the era of thrombolysis to individual patient profiling. Recently, several indication parameters, e.g., "treatment time window" or "more distal vessel occlusion," are under debate for adjustment. In this article, we review the imaging strategies in acute stroke and discuss several EVT indication dogmas, which are subject to change.

Simultaneous patient presentation for endovascular thrombectomy in acute ischemic stroke

BACKGROUND

Increased demand for endovascular thrombectomy has increased the likelihood of simultaneous patient presentation leading to competing demand for time-critical treatment that could adversely impact patient outcomes. We aimed to quantify the occurrence of simultaneous patient presentation at different patient volumes.

METHODS

Empirical distributions for time of patient presentation and case duration were used to probabilistically generate arrival time and case duration for a set annual patient volume, ranging from 1 to 500 cases per year, for 16 000 independent trials at each volume. Time series were generated for each trial to represent the number of cases being performed at each minute of the year. Time series were used to calculate daily thrombectomy demand, annual concurrent demand, and hourly excess demand.

RESULTS

The patient volumes at which at least one annual occurrence of concurrent demand by two patients was 50% and 97.5% likely were 45 and 101, respectively. The volumes at which at least one annual occurrence of concurrent demand by three patients was 50% and 97.5% likely were 216 and 387, respectively. There was dramatic variation in the occurrence of excess demand by two or more patients throughout the day.

CONCLUSIONS

The occurrence of simultaneous presentation by multiple patients for endovascular thrombectomy varies with annual patient volume and time of day. Understanding these trends and the associated patient impact can inform intelligent strategies at regional and national levels for optimizing patient care within real-world financial and operational constraints.

Endovascular thrombectomy can be beneficial to acute ischemic stroke patients with large infarcts

OBJECTIVE

This study aimed to assess whether patients with acute ischemic stroke (AIS) and large infarct lesions benefit from reperfusion management. To determine the efficacy of different recanalization managements on AIS patients with Alberta Stroke Program Early CT Score (ASPECTS) < 6, the authors retrospectively analyzed hospitalized patients with AIS.

METHODS

Eighty-nine patients with AIS and ASPECTS < 6 were screened from 13,285 hospitalized patients treated by thrombolysis, thrombectomy, or conventional care in two stroke medical centers. Logistic regression or Fisher's exact test was performed for comparison of the outcome and risk events between patients treated by thrombectomy (or thrombolysis) and conventional care. The modified Rankin Scale (mRS) score was used to assess the major clinical outcome of patients 3 months after disease onset. Disease outcome was also examined by analyzing symptom improvement at discharge. In particular, mortality and symptomatic intracranial hemorrhage (sICH) were evaluated as risk factors.

RESULTS

This study included 21 patients who received thrombolysis, 36 patients receiving thrombectomy, and 32 patients receiving conventional treatment. Among these 3 treatments, only the thrombectomy group clearly showed the most encouraging clinical outcome (mRS score 0-2; p < 0.05, Fisher's exact test) and marked improvement (OR 25.84, 95% CI 2.44-273.59) compared with conventional treatment. It is noteworthy that the mortality rate of the thrombectomy and thrombolysis group was similar to that of the conventional group, and thrombectomy and thrombolysis increased the risk of sICH in comparison with conventional care (p < 0.05, Fisher's exact test).

CONCLUSIONS

Patients with AIS and ASPECTS < 6 definitely benefited from thrombectomy with higher sICH risk, whereas thrombolysis management showed similar efficacy to the control group.

Acute ischemic stroke patients with diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomography Score ≤ 5 can benefit from endovascular treatment: a single-center experience and literature review

PURPOSE

The recommendation strength of the guidelines for mechanical thrombectomy among patients with large pre-treatment core infarct is weak. We evaluated the safety and outcome of endovascular treatment for acute ischemic stroke with diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) ≤ 5.

METHODS

Data on acute ischemic stroke patients with DWI-ASPECTS ≤ 5 who underwent endovascular treatment within 6 h, or presented an arterial spin labeling-DWI (ASL-DWI) mismatch within 12 h, at our center were retrospectively collected. We report the clinical characteristics and outcome of every patient, and review the relevant literature.

RESULTS

Among the 19 patients who were enrolled, all experienced successful reperfusion, and 10 achieved a favorable outcome (modified Rankin scale (mRS) ≤ 2). Two patients presented with symptomatic intracranial hemorrhage (sICH); both of them had a poor outcome (mRS > 2).

CONCLUSION

Acute ischemic stroke patients with large DWI lesions caused by large vessel occlusion can achieve a favorable clinical outcome with endovascular treatment if recanalization is performed within 6 h, or after 6 h in case of an ASL-DWI mismatch.

Evaluating the Prognosis of Ischemic Stroke Using Low-Dose Multimodal Computed Tomography Parameters in Hyperacute Phase

PURPOSE

The aim of this study was to evaluate the potential value of low-dose multimodal computed tomography (CT) in predicting prognosis of acute ischemic stroke (AIS) within 6 hours.

METHODS

The admission "one-stop-shop" multimodal CT examination, including noncontrast CT (NCCT), low-dose CT perfusion, and CT angiography (CTA), was performed in patients with symptoms of stroke within 6 hours. Noncontrast CT, CTA source image (CTA-SI), cerebral blood flow (CBF), cerebral blood volume (CBV), time to peak (TTP), and mean transit time (MTT) maps were studied using Alberta Stroke Program Early CT Score (ASPECTS). The regional leptomeningeal collateral (rLMC) score (0-20) was dichotomized into 2 groups: good (11-20) and poor (0-10) rLMC. Poor functional outcomes were defined by a modified Rankin scale score of 3 to 6.

RESULTS

One hundred forty-four patients were ultimately selected; 43.8% of them showed poor functional outcomes. They had lower ASPECTSs on NCCT, CTA-SI, CBV, CBF, TTP, and MTT, and poor rLMC was more frequently associated with poor functional outcomes (all P < 0.001). In the multivariate analysis for AIS patients with conservative treatment, CTA-SI-ASPECTS 6 or less (odds ratio [OR], 5.9; 95% confidence interval [95% CI], 1.9-18.4; P = 0.002) and poor collaterals (OR, 5.0; 95% CI, 1.3-15.4; P = 0.017), CBV-ASPECTS 6 or less (OR, 8.0; 95% CI, 2.7-24.0; P < 0.001), CBF-ASPECTS 4 or less (OR, 8.0; 95% CI, 2.0-31.5; P = 0.003), MTT-ASPECTS≤3 (OR, 5.8; 95% CI, 1.8-18.1; P = 0.003), TTP-ASPECTS 4 or less (OR, 5.0; 95% CI, 1.6-15.1; P = 0.005), and NCCT-ASPECTS 8 or less (OR, 5.9; 95% CI, 1.7-20.4; P = 0.005) were significantly associated with poor functional outcome. In the multivariate analysis for AIS patients with thrombolysis, CTA-SI-ASPECTS 6 or less (OR, 27.5; 95% CI, 2.9-262.3; P = 0.004), poor collaterals (OR, 28.0; 95% CI, 2.8-283.0; P < 0.028), and CBV-ASPECTS 6 or less (OR, 18.0; 95% CI, 3.0-107.7; P = 0.002) were associated with poor functional outcomes. Furthermore, the area under the curve (AUC) of the combination of CTA-SI-ASPECTS 6 or less, poor collaterals, and CBV-ASPECTS 6 or less (AUC, 0.87) was greater than that for any single parameter alone: CTA-SI-ASPECTS 6 or less (AUC, 0.80; P < 0.001), poor collaterals (AUC, 0.76; P < 0.001), and CBV-ASPECTS 6 or less (AUC, 0.81; P = 0.002).

CONCLUSIONS

The combination of CTA-SI-ASPECTS, collaterals, and CBV-ASPECTS may improve predictive power compared with a single parameter alone.

Interobserver agreement between senior radiology resident, neuroradiology fellow, and experienced neuroradiologist in the rating of Alberta Stroke Program Early Computed Tomography Score (ASPECTS)

PURPOSE

The distribution of ischemic changes caused by infarction of the middle cerebral artery (MCA) territories is usually measured using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). The first interpreter of the brain computed tomography (CT) in the emergency department is the on-call radiology resident. The primary objective of this study was to describe the agreement of the ASPECTS performed retrospectively by the resident compared with expert raters. The second objective was to ascertain the appropriate window setting for early detection of acute ischemic stroke and good interobserver agreement between the interpreters.

METHODS

We identified consecutive patients presenting with hemiparesis or aphasia at the emergency department who underwent brain CT and CT angiography. Each scan was rated using ASPECTS by senior radiology resident, neuroradiology fellow, and later by consensus between two expert raters. Statistical analysis included determination of Cohen's kappa (κ) coefficient and intraclass correlation coefficient (ICC).

RESULTS

A total of 43 patients met our study criteria. Interobserver agreements for ASPECTS varied from 0.486 to 0.678 in Cohen's κ coefficient between consensus of two neuroradiologists and a neuroradiology fellow, and from 0.198 to 0.491 for consensus between two neuroradiologists and a senior radiology resident. ICC among three raters (expert consensus, neuroradiology fellow, and senior radiology resident), was very good when 8 HU window width and 32 HU center level setting was used.

CONCLUSION

ASPECTS varied among raters. However, when using a narrowed window setting for interpretation, interobserver agreement improved.

Diffusion-weighted imaging lesion growth occurs despite recanalization in acute ischemic stroke: Implications for future treatment trials

Background

A proportion of patients presenting with acute small ischemic strokes have poor functional outcomes, even following rapid recanalization treatment.

Aims

Infarct growth may occur even after successful recanalization and could represent an appropriate endpoint for future stroke therapy trials.

Methods

Magnetic resonance diffusion-weighted imaging lesion volumes were obtained at 5 h (initial posttreatment) and 24 h (follow-up) after acute stroke treatment for n = 33 in ischemic stroke patients. Sample sizes per arm (90% power, 30% effect size) for diffusion-weighted imaging lesion growth between initial and 24 h, early change in the National Institutes of Health Stroke Scale between pre- and 24 h, National Institutes of Health Stroke Scale at 24 h, and diffusion-weighted imaging lesion volume at 24 h were estimated to power a placebo-controlled stroke therapy trial.

Results

For patients with poor recanalization (modified thrombolysis in cerebral infarction <2 a; modified arterial occlusion lesion = 0–2) (n = 11), the median diffusion-weighted imaging lesion growth was 8.1 (interquartile range: 4.5, 22.4) ml and with good recanalization (modified thrombolysis in cerebral infarction =2 b or 3; modified arterial occlusion lesion = 3) (n = 22), the median diffusion-weighted imaging lesion growth was 10.0 (interquartile range: 6.0, 28.2) ml ( P = 0.749). When considering a 30% effect size, the sample size required per arm to achieve significance in an acute stroke study would be: (1) N = 49 for the diffusion-weighted imaging lesion growth between initial posttreatment and follow-up time points, (2) N = 65 for the change in the National Institutes of Health Stroke Scale between admission and 24 h, (3) N = 259 for the National Institutes of Health Stroke Scale at 24 h, and (4) N = 256 for diffusion-weighted imaging volume at 24 h.

Conclusion

Despite best efforts to recanalize the ischemic brain, early diffusion-weighted imaging lesion growth still occurs. Treatment trials in stroke should consider early diffusion-weighted imaging lesion growth as a surrogate outcome measure to significantly reduce sample sizes.

Combined Evaluation of Noncontrast CT ASPECTS and CT Angiography Collaterals Improves Detection of Large Infarcts in Proximal Artery Occlusive Stroke

BACKGROUND AND PURPOSE

Imaging may identify patients with very large infarcts who are unlikely to benefit from intra-arterial therapy. Although computed tomography (CT) is widely used, it suffers from poor sensitivity. We sought to evaluate whether combined evaluation of noncontrast CT (NCCT) and CT angiography (CTA) collaterals would improve the detection of large infarcts.

METHODS

All patients with anterior circulation proximal artery occlusion and baseline CT, CTA, and magnetic resonance imaging (MRI) performed were identified. NCCT ASPECTS, CTA collateral score (CS), and diffusion-weighted imaging (DWI) lesion volume were determined. Receiver-operating characteristic analyses were performed to test the discrimination of NCCT ASPECTS 0-4, CTA malignant collaterals (CS = 0: absent collaterals in >50% of M2 territory), and the combination for DWI volume > 100 mL.

RESULTS

Among 54 patients, mean age was 67 years; median NIHSS was 14. Occlusion locations were ICA terminus (18 [33%]), MCA M1 (20 [37%]), and M2 (16 [30%]). Median NCCT ASPECTS was 8; 8 (15%) had ASPECTS 0-4. Median CTA CS was 2; 9 (17%) were categorized as malignant. Median DWI lesion volume was 25 mL; 12 (22%) had lesions >100 mL. Individually, the CTA malignant collateral profile (98%) and NCCT ASPECTS 0-4 (100%) demonstrated high specificity for DWI lesion volume >100 mL, but had suboptimal sensitivity (both 67%). In the combined approach (CTA CS = 0 and/or NCCT ASPECTS ≤4), the sensitivity improved significantly to 92%, while maintaining high specificity (98%).

CONCLUSIONS

Combined evaluation of NCCT ASPECTS and CTA collaterals identifies patients with infarcts >100 mL with high accuracy, and can improve patient selection using current CT techniques.

NCCT and CTA-based imaging protocol for endovascular treatment selection in late presenting or wake-up strokes

Introduction

Recently, the benefit of selecting patients for endovascular treatment (EVT) beyond the 6-hour time window using a tissue-based approach was demonstrated in two randomized trials. The optimal imaging protocol for selecting patients is under debate, and it is still unknown if a simpler and faster protocol may adequately select patients with wake-up stroke (WUS) and late-presenting stroke (LPS) for EVT.

Objective

To compare outcomes of patients submitted to EVT presenting within 6 hours of symptom onset or 6–24 hours after last seen well, selected using non-contrast computed tomography (NCCT) and CT angiography (CTA).

Methods

An observational study was performed, which included consecutive patients with anterior circulation ischemic stroke with large vessel occlusion treated with EVT. Patients presenting within 6 hours were treated if their NIH Stroke Scale (NIHSS) score was ≥6 and Alberta Stroke Program Early CT score (ASPECTS) was ≥6, while patients presenting with WUS or 6–24 hours after last seen well (WUS/LPS) were treated if their NIHSSscore was ≥12 and ASPECTS was ≥7.

Results

249 patients were included, 63 of whom were in the WUS/LPS group. Baseline characteristics were similar between groups, except for longer symptom-recanalization time, lower admission NIHSS (16 vs 17, P=0.038), more frequent tandem occlusions (25.4% vs 11.8%, P=0.010), and large artery atherosclerosis etiology (22.2% vs 11.8%, P=0.043) in the WUS/LPS group. No differences in symptomatic intracranial hemorrhage, peri-procedural complications or mortality were found between groups. Three-month functional independence was similar in both groups (65.1% in WUS/LPS vs 57.0% in ≤6 hours, P=0.259) and no differences were found after adjustment for confounders.

Conclusions

This real-world observational study suggests that EVT may be safe and effective in patients with WUS and LPS selected using clinical-core mismatch (high NIHSS/high ASPECTS in NCCT).

Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

Early recanalization after endovascular treatment could improve the prognosis of acute ischemia stroke. Futile recanalization often occurred which was one of the main causes of failure. By now the mechanisms of futile recanalization were not clear. They are probably concerned with bad collateral circulation, subacute reocclusion, large hypoperfusion volumes, microvascular compromise, and impaired cerebral autoregulation. Previous research found that some of the image markers could be used as the accurate predictors for poor prognosis after successful treatment in order to identify the patients who were not suitable for recanalization and reduce some of the unnecessary cost. Predictors for futile recanalization mentioned in our article can be used for supplement to make decision for endovascular treatment.

Refocusing Neuroprotection in Cerebral Reperfusion Era: New Challenges and Strategies

Pathophysiological processes of stroke have revealed that the damaged brain should be considered as an integral structure to be protected. However, promising neuroprotective drugs have failed when translated to clinical trials. In this review, we evaluated previous studies of neuroprotection and found that unsound patient selection and evaluation methods, single-target treatments, etc., without cerebral revascularization may be major reasons of failed neuroprotective strategies. Fortunately, this may be reversed by recent advances that provide increased revascularization with increased availability of endovascular procedures. However, the current improved effects of endovascular therapy are not able to match to the higher rate of revascularization, which may be ascribed to cerebral ischemia/reperfusion injury and lacking of neuroprotection. Accordingly, we suggest various research strategies to improve the lower therapeutic efficacy for ischemic stroke treatment: (1) multitarget neuroprotectant combinative therapy (cocktail therapy) should be investigated and performed based on revascularization; (2) and more efforts should be dedicated to shifting research emphasis to establish recirculation, increasing functional collateral circulation and elucidating brain–blood barrier damage mechanisms to reduce hemorrhagic transformation. Therefore, we propose that a comprehensive neuroprotective strategy before and after the endovascular treatment may speed progress toward improving neuroprotection after stroke to protect against brain injury.

Primary angioplasty and stenting may be superior to thrombectomy for acute atherosclerotic large-artery occlusion

Objective The objective of this article is to compare the effectiveness of primary angioplasty and/or stenting with stent retriever thrombectomy in acute anterior large-vessel occlusion due to atherosclerotic disease. Methods Patients were retrospectively reviewed from the endovascular treatment for acute anterior circulation ischemic stroke registry. Patients with large-vessel occlusions due to atherosclerosis were selected. We evaluated modified Rankin Scale (mRS) score at 90 days, modified thrombolysis in cerebral infarction (mTICI) score immediately post-procedure, and symptomatic and asymptomatic intracranial hemorrhage within 72 hours. Results Of 302 patients with acute anterior circulation occlusion due to atherosclerotic disease, 269 were treated with stent retriever thrombectomy as first-line therapy and 33 with angioplasty and/or stenting. Patients who received primary angioplasty treatment showed favorable independent outcome at 90 days (69.7% (23/33) vs 47.6% (128/269), p = 0.02) and lower rate of asymptomatic intracranial hemorrhage (9.1% (3/23) vs 30.5% (82/269), p = 0.01). Recanalization immediately post procedure did not differ (78.8%% (26/33) vs 86.2% (232/269), p = 0.29). Primary angioplasty therapy (OR, 0.27; 95% confidence interval (CI): 0.08-0.90; p = 0.03) and small baseline infarct (OR 0.36: 0.16-0.82; p = 0.02) were protective factors against poor functional outcome, while old age (OR 1.04:1.01-1.07; p = 0.006), severe neurological deficits (OR 3.76: 2.00-7.07; p < 0.001), and high glucose (OR 1.11: 1.01-1.23; p = 0.03) were associated with poor prognosis. Conclusions Patients with acute anterior circulation large-vessel occlusion due to atherosclerosis may benefit from urgent angioplasty and/or stenting as first-line therapy. Randomized controlled trials are warranted.

Endovascular thrombectomy beyond 12 hours of stroke onset: a stroke network’s experience of late intervention

Background

Selected patients with proximal anterior circulation ischemic stroke who demonstrate limited infarct and sufficient penumbra may benefit from endovascular thrombectomy (EVT) beyond conventional time limits.

Objective

To perform a retrospective review of all cases of EVT performed at our institution for proximal anterior circulation acute ischemic stroke with onset >12 hours.

Materials and methods

Patients were assessed with non-contrast CT brain and multiphase CT angiography, with Alberta Stroke Program Early CT Score (ASPECTS) and collateral grade informing patient selection. Data, including patient demographics, workflow, neuroimaging findings, procedural details, recanalization rates, and 90-day functional outcomes, were collected.

Results

Of the 542 consecutive endovascular thrombectomy cases performed during the study period, 25 (4.6%) were >12 hours from stroke onset. Median age was 69 years (IQR 55–80), median National Institute of Health Stroke Scale score on presentation was 14 (IQR 11–18.5), median ASPECTS was 8 (IQR 8–9), and rate of moderate–good collateral status was 96% (n=24). Median time to groin puncture was 14 hours 40 min (IQR 12 hours 36 min – 16 hours 18 min). Rate of successful recanalization (modified Thrombolysis in Cerebral infarction 2b–3) was 88% (n=22). Rate of functional independence (90-day modified Rankin Scale score 0–2) was 52% (n=13). There were no cases of symptomatic intracranial haemorrhage and 90-day mortality rate was 12% (n=3).

Conclusion

With the use of ASPECTS and collateral grade to guide patient selection, good functional outcome with acceptable safety parameters may be achieved in patients undergoing EVT beyond 12 hours from stroke onset.

Current evidence for endovascular therapy in stroke and remaining uncertainties

Class 1 level A evidence now supports endovascular thrombectomy as best practice in the management of large vessel occlusion acute ischaemic stroke. However, significant questions pertaining to initial imaging, radiological assessment, patient selection and therapeutic limits remain unanswered. A specific cohort of patients who benefit from endovascular thrombectomy has been established, although current uncertainties regarding selection of those not meeting top-tier evidence criteria may potentially deny certain patients the benefit of intervention. This is of particular relevance in patients presenting in a delayed manner. Whilst superior outcomes are achieved with reduced time to endovascular reperfusion, denying patients intervention based on symptom duration alone may not be appropriate. Advanced understanding of ischaemic stroke pathophysiology supports an individualized approach to patient evaluation, given variance in the rate of ischaemic core progression and the extent of salvageable penumbra. Physiological imaging techniques may therefore be utilized to better inform patient selection for endovascular thrombectomy and evidence suggests that a transition from time-based to tissue-based therapeutic thresholds may be of greater value. Multiple ongoing randomized controlled trials aim to further define the benefit of endovascular thrombectomy and it is hoped that these results will advance, and possibly broaden, patient selection criteria to ensure that maximum benefit from the intervention may be achieved.

Outcomes of endovascular treatment for acute large-vessel ischaemic stroke more than 6 h after symptom onset

BACKGROUND AND OBJECTIVES

Benefit from endovascular thrombectomy (EVT) for large-vessel occlusion (LVO) acute ischaemic stroke (AIS) is well demonstrated. Furthermore, emerging evidence supports efficacy in appropriately selected patients treated beyond current recommendations of 6 h. We evaluated clinical outcomes in patients undergoing late EVT at our institution.

METHODS

Retrospective review of prospectively collected clinical database on 355 patients who underwent EVT for LVO AIS. Data collected consisted of patient demographics, radiological findings and outcome details. Outcomes, including 90-day functional status, recanalization, symptomatic intracranial haemorrhage (sICH) and 90-day mortality, for patients undergoing EVT <6 h, >6 h, and >7.3 h, were compared.

RESULTS

A total of 355 patients underwent EVT for LVO AIS at our institution during the review period, with 74 (21%) patients treated ≥6 h from symptom onset. Successful recanalization was achieved in 285 (80%) patients, with 228 (81%) achieving a mTICI ≥2b in the <6 h group, and 57 (77%) in the >6 h group (P = 0.429). Ninety-day functional independence (mRS 0-2) was achieved in 162 (46%) patients, with 130 (46%) achieving a mRS of 0-2 in the <6 h group, and 32 (43%) in the >6 h group (P = 0.643). No significant differences were found in rates of sICH or 90-day mortality. No significant differences in functional independence, recanalization rates, sICH or mortality were identified in patients treated with EVT >7.3 h compared to <7.3 h.

CONCLUSIONS

In appropriately selected patients, EVT >6 h was associated with comparable outcomes to those treated <6 h. These data support a physiological approach to patient selection.

Acute Ischemic Pediatric Stroke Management: An Extended Window for Mechanical Thrombectomy?

Ischemic stroke is a rare condition to afflict the pediatric population. Congenital cardiomyopathy represents one of several possible etiologies in children. We report a 9-year-old boy who developed right middle cerebral artery stroke secondary to primary restrictive cardiomyopathy. In the absence of pediatric guidelines, the child met adult criteria for mechanical thrombectomy given the small core infarct and large penumbra. The literature suggests children may benefit from mechanical thrombectomy in carefully selected cases. Our patient exemplifies specific circumstances in which acute stroke therapy with thrombolysis and thrombectomy may be safe.

Clinical Imaging Factors Associated With Infarct Progression in Patients With Ischemic Stroke During Transfer for Mechanical Thrombectomy

Importance

When transferred from a referring hospital (RH) to a thrombectomy-capable stroke center (TCSC), patients with initially favorable imaging profiles (Alberta Stroke Program Early CT Score [ASPECTS] ≥6) often demonstrate infarct progression significant enough to make them ineligible for mechanical thrombectomy at arrival. In rapidly evolving stroke care networks, the question of the need for vascular imaging at the RHs remains unsolved, resulting in an important amount of futile transfers for thrombectomy.

Objective

To examine the clinical imaging factors associated with unfavorable imaging profile evolution for thrombectomy in patients with ischemic stroke initially transferred to non-TCSCs.

Design, Setting, and Participants

Data from patients transferred from 1 of 30 RHs in our regional stroke network and presenting at our TCSC from January 1, 2010, to January 1, 2016, were retrospectively analyzed. Consecutive patients with acute ischemic stroke initially admitted to a non-thrombectomy-capable RH and transferred to our center for which a RH computed tomography (CT) and a CT angiography (CTA) at arrival were available for review.

Main Outcomes and Measures

ASPECTS were evaluated. The adequacy of leptomeningeal collateral blood flow was rated as no or poor, decreased, adequate, or augmented per the adapted Maas scale. The main outcome was an ASPECTS decay, defined as an initial ASPECTS of 6 or higher worsening between RH and TCSC CTs to a score of less than 6 (making the patient less likely to derive clinical benefit from thrombectomy at arrival).

Results

A total of 316 patients were included in the analysis (mean [SD] age, 70.3 [14.2] years; 137 [43.4%] female). In multivariable models, higher National Institutes of Health Stroke Score, lower baseline ASPECTSs, and no or poor collateral blood vessel status were associated with ASPECTS decay, with collateral blood vessel status demonstrating the highest adjusted odds ratio of 5.14 (95% CI, 2.20-12.70; P < .001). Similar results were found after stratification by vessel occlusion level.

Conclusions and Relevance

In patients with ischemic stroke transferred for thrombectomy, poor collateral blood flow and stroke clinical severity are the main determinants of ASPECTS decay. Our findings suggest that in certain subgroups vascular imaging, including collateral assessment, can play a crucial role in determining the benefits of transfer for thrombectomy.