Identifying large ischemic core volume ranges in acute stroke that can benefit from mechanical thrombectomy

Thrombectomy for patients with a large infarct core: a study-level meta-analysis with trial sequential analysis

Background

The effectiveness and safety of endovascular treatment compared with medical management alone regarding outcomes for patients with a large infarct core remain uncertain.

Objectives

To juxtapose the clinical outcomes of thrombectomy versus the best medical care in patients with a large infarct core.

Design

Systematic review and meta-analysis.

Data sources and methods

We conducted searches in PubMed, Cochrane, and Embase for articles published up until November 8, 2023. Randomized trials were selected for inclusion if they encompassed patients with large vessel occlusion and sizable strokes receiving thrombectomy. The primary outcome was functional outcomes at 3 months after pooling data using random-effects modeling. Safety outcomes included mortality at 3 months, symptomatic intracranial hemorrhage (SICH), and decompressive craniectomy. We performed a trial sequential analysis to balance type I and II errors.

Results

From 904 citations, we identified six randomized trials, involving a cohort of 1897 patients with a large ischemic region. Of these, 953 individuals underwent endovascular thrombectomy. At 3 months, thrombectomy was significantly correlated with better neurological prognosis, as evidenced by the increased odds of good functional outcomes (odds ratio (OR), 2.90; 95% confidence interval (CI), 2.08-4.05) and favorable functional outcomes (OR, 2.40; 95% CI, 1.86-3.09). Mortality rates did not demonstrably diminish as a consequence of the endovascular management (OR, 0.78; 95% CI, 0.58-1.06). However, the incidence of SICH was greater in the thrombectomy group compared to those with only medical treatment (5.5% vs 3.2%; OR, 1.77; 95% CI, 1.11-2.83). The application of trial sequential analysis yielded definitive evidence regarding favorable function outcomes and a shift in the distribution of modified Rankin scale scores at 3 months; however, others remained inconclusive.

Conclusion

The results from most of the included trials display consistency. Meta-analysis of these six randomized trials offers high-quality evidence that thrombectomy significantly mitigates disability in patients with a large infarction, while also increasing the risk of SICH.

Trial registration

PROSPERO, CRD42023480359.

Optimizing Acute Stroke Segmentation on MRI Using Deep Learning: Self-Configuring Neural Networks Provide High Performance Using Only DWI Sequences

Segmentation of infarcts is clinically important in ischemic stroke management and prognostication. It is unclear what role the combination of DWI, ADC, and FLAIR MRI sequences provide for deep learning in infarct segmentation. Recent technologies in model self-configuration have promised greater performance and generalizability through automated optimization. We assessed the utility of DWI, ADC, and FLAIR sequences on ischemic stroke segmentation, compared self-configuring nnU-Net models to conventional U-Net models without manual optimization, and evaluated the generalizability of results on an external clinical dataset. 3D self-configuring nnU-Net models and standard 3D U-Net models with MONAI were trained on 200 infarcts using DWI, ADC, and FLAIR sequences separately and in all combinations. Segmentation results were compared between models using paired t-test comparison on a hold-out test set of 50 cases. The highest performing model was externally validated on a clinical dataset of 50 MRIs. nnU-Net with DWI sequences attained a Dice score of 0.810 ± 0.155. There was no statistically significant difference when DWI sequences were supplemented with ADC and FLAIR images (Dice score of 0.813 ± 0.150; p = 0.15). nnU-Net models significantly outperformed standard U-Net models for all sequence combinations (p < 0.001). On the external dataset, Dice scores measured 0.704 ± 0.199 for positive cases with false positives with intracranial hemorrhage. Highly optimized neural networks such as nnU-Net provide excellent stroke segmentation even when only provided DWI images, without significant improvement from other sequences. This differs from-and significantly outperforms-standard U-Net architectures. Results translated well to the external clinical environment and provide the groundwork for optimized acute stroke segmentation on MRI.

Ischaemic Stroke, Thromboembolism and Clot Structure

Ischaemic stroke is a major cause of morbidity and mortality worldwide. Blood clotting and thromboembolism play a central role in the pathogenesis of ischaemic stroke. An increasing number of recent studies indicate changes in blood clot structure and composition in patients with ischaemic stroke. In this review, we aim to summarise and discuss clot structure, function and composition in ischaemic stroke, including its relationships with clinical diagnosis and treatment options such as thrombolysis and thrombectomy. Studies are summarised in which clot structure and composition is analysed both in vitro from patients' plasma samples and ex vivo in thrombi obtained through interventional catheter-mediated thrombectomy. Mechanisms that drive clot composition and architecture such as neutrophil extracellular traps and clot contraction are also discussed. We find that, while in vitro clot structure in plasma samples from ischaemic stroke patients are consistently altered, showing denser clots that are more resistant to fibrinolysis, current data on the composition and architecture of ex vivo clots obtained by thrombectomy are more variable. With the potential of advances in technologies underpinning both the imaging and retrieving of clots, we expect that future studies in this area will generate new data that is of interest for the diagnosis, optimal treatment strategies and clinical management of patients with ischaemic stroke.

AC-ASPECTS, ACh-ASPECTS, and H-ASPECTS: new imaging scales to assess territorial and total cerebral hemispheric ischemic injury

Background

The extent of ischemic injury in acute stroke is assessed in clinical practice using the Acute Stroke Prognosis Early CT Score (ASPECTS) rating system. However, current ASPECTS semi-quantitative topographic scales assess only the middle cerebral artery (MCA) (original ASPECTS) and posterior cerebral (PC-ASPECTS) territories. For treatment decision-making in patients with anterior cerebral artery (ACA) occlusions and internal carotid artery (ICA) occlusions with large ischemic cores, measures of all hemispheric regions are desirable.

Methods

In this cohort study, anatomic rating systems were developed for the anterior cerebral (AC-ASPECTS, 3 points) and anterior choroidal artery (ACh-ASPECTS, 1 point) territories. In addition, a total supratentorial hemisphere (H-ASPECTS, 16 points) score was calculated as the sum of the MCA ASPECTS (10 regions), supratentorial PC-ASPECTS (2 regions), AC-ASPECTS (3 regions), and ACh-ASPECTS (1 region). Three raters applied these scales to initial and 24 h CT and MR images in consecutive patients with ischemic stroke (IS) due to ICA, M1-MCA, and ACA occlusions.

Results

Imaging ratings were obtained for 96 scans in 50 consecutive patients with age 74.8 (±14.0), 60% female, NIHSS 15.5 (9.25-20), and occlusion locations ICA 34%; M1-MCA 58%; and ACA 8%. Treatments included endovascular thrombectomy +/- thrombolysis in 72%, thrombolysis alone in 8%, and hemicraniectomy in 4%. Among experienced clinicians, inter-rater reliability for AC-, ACh-, and H-ASPECTS scores was substantial (kappa values 0.61-0.80). AC-ASPECTS abnormality was present in 14% of patients, and ACh-ASPECTS abnormality in 2%. Among patients with ACA and ICA occlusions, H-ASPECTS scores compared with original ASPECTS scores were more strongly associated with disability level at discharge, ambulatory status at discharge, discharge destination, and combined inpatient mortality and hospice discharge.

Conclusion

AC-ASPECTS, ACh-ASPECTS, and H-ASPECTS expand the scope of acute IS imaging scores and increase correlation with functional outcomes. This additional information may enhance prognostication and decision-making, including endovascular thrombectomy and hemicraniectomy.

Hyperglycemia Is Associated With Computed Tomography Perfusion Core Volume Underestimation in Patients With Acute Ischemic Stroke With Large-Vessel Occlusion

Background

CT Perfusion (CTP) predictions of infarct core play an important role in the determination of treatment eligibility in large vessel occlusion (LVO) acute ischemic stroke (AIS). Prior studies have demonstrated that blood glucose can affect cerebral blood flow (CBF). Here we examine the influence of acute and chronic hyperglycemia on CTP estimations of infarct core.

Methods

From our prospectively collected multi-center observational cohort, we identified patients with LVO AIS who underwent CTP with RAPID (IschemaView, Stanford, CA) post-processing, followed by endovascular therapy with substantial reperfusion (TICI 2b-3) within 90 minutes, and final infarct volume (FIV) determination by MRI 48-72 hours post-treatment. Core volume over- and under-estimations were defined as a difference of at least 20 mL between CTP-RAPID predicted infarct core and DWI FIV. Primary outcome was the association of presentation glucose and HgbA1c with underestimation (UE) of core volume and was measured using multivariable logistic regression adjusted for comorbidities and presentation characteristics. Secondary outcomes included frequency of overestimation (OE) of infarct core.

Results

Among 256 patients meeting inclusion criteria, median age was 67 [IQR 57-77], 51.6% were female, and 132 (51.6%) and 93 (36.3%) had elevated presentation glucose and elevated HgbA1c, respectively. Median CTP-predicted core was 6 mL [IQR 0-30], median DWI FIV was 14 mL [IQR 6-43] and median difference was 12 mL [IQR 5-35]. Twenty-eight (10.9%) patients had infarct core OE and 68 (26.6%) had UE. Compared to those with no UE, patients with UE had elevated blood glucose (median 119 [103-155] vs 138 [117-195], p=0.002) and HgbA1c (median 5.80 [5.40-6.40] vs 6.40 [5.50-7.90], p=0.009). In multivariable analysis, UE was independently associated with elevated glucose (aOR 2.10, p=0.038) and HgbA1c (aOR 2.37, p=0.012). OE was associated with lower presentation blood glucose (median 109 [ 99-132] in OE vs 127 [107-172] in no OE, p=0.003) and HgbA1c (5.6 [IQR 5.1 - 6.2] in OE vs 5.90 [5.50-6.70] in no OE, p=0.012).

Conclusions

Acute and chronic hyperglycemia were strongly associated with CTP UE in patients with LVO AIS undergoing EVT. Glycemic state should be considered when interpreting CTP findings in patients with LVO AIS.

Endovascular treatment without postoperative decompressive craniectomy in an acute stroke patient with very large ischemic infarct core: A case report and literature review

Introduction

The benefits of endovascular treatment (EVT) on large ischemic infarct core mainly focus on a core size of 70-150 ml. The relationship between EVT and very large ischemic infarct core (>150 ml) is unclear. We herein present an acute stroke patient who achieved functional independence after EVT without postoperative decompressive craniectomy despite very large ischemic infarct core.

Case report

A 50-year-old Asian male was admitted to our hospital with "sudden disturbance of consciousness with left limb weakness for 11 hours". The patient had a history of clipping treatment for ruptured aneurysms. After an emergency CTA and CTP, very large ischemic core of 190 ml and a mismatch ratio (Tmax > 6s volume/core volume) of 1.9 were shown in preoperative imaging. EVT was performed, and postoperative strict monitoring was conducted without decompressive craniectomy. The patient was discharged from the hospital on the 16th day, scoring 2 on the modified Rankin scale at a 2-year follow-up.

Conclusion

Imaging suggests very large ischemic infarct core; if there is a substantial mismatch between major functional areas (large ischemic penumbra) and the patient is relatively young, aggressive EVT may be beneficial.

Long term outcome after endovascular treatment for large ischemic core acute stroke is associated with hypoperfusion intensity ratio and onset-to-reperfusion time

BACKGROUND

Endovascular treatment (EVT) is effective for large vessel occlusion (LVO) stroke with smaller volumes of CT perfusion (CTP)-defined core. However, the influence of perfusion imaging during thrombectomy on the functional outcomes of patients with large ischemic core (LIC) stroke at both early and late time windows is uncertain in real-world practice.

METHOD

A retrospective analysis was performed on 99 patients who underwent computed tomography angiography (CTA) and CT perfusion (CTP)-Rapid Processing of Perfusion and Diffusion (RAPID) before EVT and had a baseline ischemic core ≥ 50 mL and/or Alberta Stroke Program Early CT Score (ASPECTS) score of 0-5. The primary outcome was the three-month modified Rankin Scale (mRS) score. Data were analyzed by binary logistic regression and receiver operating characteristic (ROC) curves.

RESULTS

A fair outcome (mRS, 0-3) was found in 34 of the 99 patients while 65 had a poor prognosis (mRS, 4-6). The multivariate logistic regression analysis showed that onset-to-reperfusion (OTR) time (odds ratio [OR], 1.004; 95% confidence interval [CI], 1.001-1.007; p = 0.008), ischemic core (OR, 1.066; 95% CI, 1.024-1.111; p = 0.008), and the hypoperfusion intensity ratio (HIR) (OR, 70.898; 95% CI, 1.130-4450.152; p = 0.044) were independent predictors of outcome. The combined results of ischemic core, HIR, and OTR time showed good performance with an area under the ROC curve (AUC) of 0.937, significantly higher than the individual variables (p < 0.05) using DeLong's test.

CONCLUSIONS

Higher HIR and longer OTR time in large core stroke patients were independently associated with unfavorable three-month outcomes after EVT.

Long-Term Effect of Mechanical Thrombectomy in Stroke Patients According to Advanced Imaging Characteristics

PURPOSE

Data on long-term effect of mechanical thrombectomy (MT) in patients with large ischemic cores (≥ 70 ml) are scarce. Our study aimed to assess the long-term outcomes in MT-patients according to baseline advanced imaging parameters.

METHODS

We performed a single-centre retrospective cohort study of stroke patients receiving MT between January 1, 2010 and December 31, 2018. We assessed baseline imaging to determine core and mismatch volumes and hypoperfusion intensity ratio (with low ratio reflecting good collateral status) using RAPID automated post-processing software. Main outcomes were cross-sectional long-term mortality, functional outcome and quality of life by May 2020. Analysis were stratified by the final reperfusion status.

RESULTS

In total 519 patients were included of whom 288 (55.5%) have deceased at follow-up (median follow-up time 28 months, interquartile range 1-55). Successful reperfusion was associated with lower long-term mortality in patients with ischemic core volumes ≥ 70 ml (adjusted hazard ratio (aHR) 0.20; 95% confidence interval (95% CI) 0.10-0.44) and ≥ 100 ml (aHR 0.26; 95% CI 0.08-0.87). The effect of successful reperfusion on long-term mortality was significant only in the presence of relevant mismatch (aHR 0.17; 95% CI 0.01-0.44). Increasing reperfusion grade was associated with a higher rate of favorable outcomes (mRS 0-3) also in patients with ischemic core volume ≥ 70 ml (aOR 3.58, 95% CI 1.64-7.83).

CONCLUSION

Our study demonstrated a sustainable benefit of better reperfusion status in patients with large ischemic core volumes. Our results suggest that patient deselection based on large ischemic cores alone is not advisable.

Endovascular thrombectomy for acute ischemic stroke in elderly patients with large ischemic cores

BACKGROUND

Understanding the benefits and risks of endovascular therapy (EVT) is crucial for elderly patients with large ischemic cores, as the combination of advanced age and extensive brain infarction may negatively impact clinical outcomes.

METHODS

The study retrospectively analyzed clinical outcomes for elderly stroke patients (age ≥ 70) with large ischemic cores (Alberta Stroke Program Early CT Score [ASPECTS] < 6 or ischemic cores ≥ 70 ml) in the anterior circulation using data from our prospective database between June 2018 and January 2022. The effectiveness and risks of EVT in those patients were investigated, with the primary outcome being fair outcome (modified Rankin Scale, mRS ≤ 3).

RESULTS

Among 182 elderly patients with large ischemic core volume (120 in the EVT group and 62 in the non-EVT group), 20.9% (38/182, 22.5% in the EVT group vs. 17.7% in the non-EVT group) achieved a fair outcome. Meanwhile, 49.5% (90/182, 45.8% in the EVT group vs. 56.5% in the non-EVT group) of them died at 3 months. The benefits of EVT numerically exceeded non-EVT treatment for those aged ≤  ~ 85 years or with a mismatch volume ≥  ~ 50 ml. However, after adjustment, EVT was associated with an increased risk of symptomatic intracranial hemorrhage (aOR 4.24, 95%CI 1.262-14.247).

CONCLUSIONS

This study highlights the clinical challenges faced by elderly patients with large infarctions, resulting in poor outcomes at 3 months. EVT may still provide some benefits in this population, but it also carries an increased risk of intracranial hemorrhage.

Penumbra salvage in extensive stroke: exploring limits for reperfusion therapy

BACKGROUND

The effect of thrombectomy in patients presenting with extensive ischemic stroke at baseline is currently being investigated; it remains uncertain to what extent brain tissue may be saved by reperfusion in such patients. Penumbra salvage volume (PSV) has been described as a tool to measure the volume of rescued penumbra.

OBJECTIVE

To assess whether the effect of recanalization on PSV is dependent on the extent of early ischemic changes.

METHODS

Observational study of patients with anterior circulation ischemic stroke triaged by multimodal-CT undergoing thrombectomy. PSV was defined as the difference between baseline penumbra volume and net infarct growth to follow-up. The effect of vessel recanalization on PSV depending on the extent of early ischemic changes (defined using Alberta Stroke Program Early CT Score (ASPECTS) and core volumes based on relative cerebral blood flow) was determined using multivariable linear regression analysis, and the association with functional outcome at day 90 was tested using multivariable logistic regression.

RESULTS

384 patients were included, of whom 292 (76%) achieved successful recanalization (modified Thrombolysis in Cerebral Infarction ≥2b). Successful recanalization was independently associated with 59 mL PSV (95% CI 29.8 to 88.8 mL) and was linked to increased penumbra salvage up to an ASPECTS of 3 and core volume up to 110 mL. Recanalization was associated with a higher probability of a modified Rankin Scale score of ≤2 up to a core volume of 100 mL.

CONCLUSIONS

Recanalization was associated with significant penumbra salvage up to a lower ASPECTS margin of 3 and upper core volume margin of 110 mL. The clinical benefit of recanalization for patients with very large ischemic regions of >100 mL or ASPECTS <3 remains uncertain and requires prospective investigation.

Detrimental effect of anemia after mechanical thrombectomy on functional outcome in patients with ischemic stroke

Background

Anemia can occur due to an aspiration maneuver of blood with thrombi during mechanical thrombectomy (MT) for stroke. However, the association between postoperative anemia and stroke outcomes is unknown.

Methods

In a registry-based hospital cohort, consecutive patients with acute ischemic stroke who underwent MT were retrospectively recruited. Patients were divided into the following three groups according to their hemoglobin (Hb) concentrations within 24 h after MT; no anemia (Hb concentrations ≥13 g/dL for men and ≥ 12 g/dL for women), mild anemia (Hb concentrations of 11-13 g/dL and 10-12 g/dL, respectively), and moderate-to-severe anemia (Hb concentrations <11 g/dL and < 10 g/dL, respectively). A 3-month modified Rankin Scale score of 0-2 indicated a favorable outcome.

Results

Of 470 patients, 166 were classified into the no anemia group, 168 into the mild anemia group, and 136 into the moderate-to-severe anemia group. Patients in the moderate-to-severe anemia group were older and more commonly had congestive heart failure than those in the other groups. Patients in the moderate-to-severe anemia group also had more device passes than those in the other groups (p < 0.001). However, no difference was observed in the rate of final extended thrombolysis in cerebral infarction ≥2b reperfusion or intracranial hemorrhage among the groups. A favorable outcome was less frequently achieved in the moderate-to-severe anemia group than in the no anemia group (adjusted odds ratio, 0.46; 95% confidence interval, 0.26-0.81) independent of the baseline Hb concentration. A restricted cubic spline model with three knots showed that the adjusted odds ratio for a favorable outcome was lower in patients with lower Hb concentrations within 24 h after MT.

Conclusion

Moderate-to-severe anemia within 24 h after MT is independently associated with a reduced likelihood of a favorable outcome.

Clinical trial registration

https://www.clinicaltrials.gov, NCT02251665.

Cost-effectiveness of endovascular therapy for acute stroke with a large ischemic region in Japan: impact of the Alberta Stroke Program Early CT Score on cost-effectiveness

BACKGROUND

Although randomized clinical trials (RCTs) demonstrated short-term benefits of endovascular therapy (EVT) for acute ischemic stroke (AIS) with a large ischemic region, little is known about the long-term cost-effectiveness or its difference by the extent of the ischemic areas. We aimed to assess the cost-effectiveness of EVT for AIS involving a large ischemic region from the perspective of Japanese health insurance payers, and analyze it using the Alberta Stroke Program Early CT Score (ASPECTS).

METHODS

The Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Large Ischemic Core Trial (RESCUE-Japan LIMIT) was a RCT enrolling AIS patients with ASPECTS of 3-5 initially determined by the treating neurologist primarily using MRI. The hypothetical cohort and treatment efficacy were derived from the RESCUE-Japan LIMIT. Costs were calculated using the national health insurance tariff. We stratified the cohort into two subgroups based on ASPECTS of ≤3 and 4-5 as determined by the imaging committee, because heterogeneity was observed in treatment efficacy. EVT was considered cost-effective if the incremental cost-effectiveness ratio (ICER) was below the willingness-to-pay of 5 000 000 Japanese yen (JPY)/quality-adjusted life year (QALY).

RESULTS

EVT was cost-effective among the RESCUE-Japan LIMIT population (ICER 4 826 911 JPY/QALY). The ICER among those with ASPECTS of ≤3 and 4-5 was 19 396 253 and 561 582 JPY/QALY, respectively.

CONCLUSION

EVT was cost-effective for patients with AIS involving a large ischemic region with ASPECTS of 3-5 initially determined by the treating neurologist in Japan. However, the ICER was over 5 000 000 JPY/QALY among those with an ASPECTS of ≤3 as determined by the imaging committee.

Endovascular therapy for acute stroke with a large infarct core: A systematic review and meta-analysis

OBJECTIVE

In this meta-analysis, we aimed to investigate the efficacy and safety of endovascular treatment (EVT) for acute ischemic stroke (AIS) patients with large core infarct.

METHODS

Three online databases of Web of Science, PubMed and Scopus were systematically searched. Original studies which evaluated AIS participants with large core infarction who underwent EVT were included. R statistical software was used for statistical analyses. Effect sizes were presented with odds ratios (ORs) with their 95% confidence intervals (CIs). The effect sizes were pooled using random effects modeling.

RESULTS

Including 47 studies and 15,173 patients, this meta-analysis showed that compared with medical management (MM), EVT was significantly associated with decreased odds of mortality (0.67, 95% CI: 0.51-0.87) and increased odds of favorable outcomes, including a modified Rankin Scale of 0-3 (2.36, 95% CI: 1.69-3.291) and of 0-2 (3.54, 95% CI: 1.96-6.4) in 90 days and remarkable improvement in National Institutes of Health Stroke Scale within 48 h after the procedure (3.6, 95% CI:1.32-9.79). Besides, there was a higher chance of intracranial hemorrhage (ICH) development (1.88, 95% CI: 1.32-2.68) but not symptomatic ICH (1.34, 95% CI: 0.78-2.31) in those who underwent EVT.

CONCLUSION

Our study suggests that EVT might be an effective and relatively safe treatment option for the treatment of AIS patients with large vessel occlusion who have large core infarcts, although more large-scale trials are needed to consolidate the results and to make inclusion criteria and the patient selection process clearer.

Predictive Value of Acute Neurological Progression Using Bayesian CT Perfusion for Acute Ischemic Stroke with Large or Median Vessel Occlusion

Objective

Since the efficacy of mechanical thrombectomy (MT) for acute cerebral infarction due to large vessel occlusion has been proven, the time available for treatment has gradually increased. Currently, under certain conditions, treatment is indicated up to 24 h from onset. Based on neurological signs and imaging diagnosis, Stroke Treatment Guideline 2021 recommends initiation of MT within 6-24 h from onset. Herein, we retrospectively investigated the relationship between cerebral perfusion imaging evaluation and prognosis in patients with acute cerebral infarction due to large or median vessel occlusion.

Methods

Fifty-one patients diagnosed with acute cerebral infarction due to large or median vessel occlusions in anterior circulation between November 2019 and December 2021 were divided into medical care and reconstructive therapy (including tissue plasminogen activator [t-PA] therapy and MT) groups. The primary outcome was changes in the National Institutes of Health Stroke Scale (NIHSS) at admission and 1 week after onset. Patients in the medical care group were divided into those whose NIHSS did not worsen and those whose NIHSS worsened. Those in the reconstructive therapy group were divided into those whose NIHSS improved and those whose NIHSS did not improve. We evaluated the relationship between improvement factors in acute neurological symptoms and penumbral and core volumes from computed tomography perfusion performed at admission.

Results

Of 45 eligible patients, 10 received medical care without t-PA or MT and 35 underwent reconstructive therapy, including t-PA and MT. Among the 10 patients in the medical care group, 3 had worsening symptoms and 7 did not. The mean and median (interquartile range [IQR]) penumbra volumes were significantly higher in patients with worsening symptoms than in those without. The receiver operating characteristic (ROC) curve showed a threshold value of 28.6 mL with an area under the curve (AUC) of 0.952. Among the 35 patients in the reconstructive therapy group, symptoms improved for 29 but did not improve for 6. The mean and median (IQR) core volumes were significantly higher in patients whose symptoms did not improve than in those whose symptoms improved. The ROC curve showed a threshold value of 25 mL and an AUC of 0.632.

Conclusion

Evaluation of penumbra volumes could detect cases with worsening symptoms in cases where medical care was performed, and evaluation of core volumes may detect cases with non-improved symptoms in cases that received reconstructive therapy.

Endovascular therapy versus medical management for acute ischemic stroke with large infarct core: Systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To compare the efficacy and safety of endovascular therapy (EVT) versus best medical management (BMM) in patients with acute ischemic stroke (AIS) with large infarct core.

METHODS

We searched Pubmed, Embase and Cochrane Central Register of Controlled Trials for published randomized clinical trials (RCTs) from inception to February 18, 2023. We defined patients with large core infarcts as having an Alberta Stroke Program early computed tomography score (ASPECTS) of 3-5. The primary outcome was functional independence, defined as a score of 0-2 on the modified Rankin scale (mRS) at 90 days. Secondary outcome was independent ambulation defined as mRS 0-3 at 90 days. Safety outcomes were mortality at 90 days, symptomatic intracranial hemorrhage (sICH) and any intracranial hemorrhage (ICH).

RESULTS

The overall treatment effect was more favourable to EVT group. EVT was significantly correlated with improvement of functional independence at 90 days (mRS 0-2) (RR = 2.40; 95 % CI, 1.82-3.16; P < 0.01; I2 = 0 %) and independent ambulation (mRS 0-3) (RR = 1,78; 95 % CI, 1.28-2.48; P < 0.01; I2 = 58 %) at 90 days. 90-day mortality was not significantly different between the two groups(RR = 0.95; 95 % CI, 0.78-1.16; P > 0.05; I2 = 0 %). The risk of sICH and any ICH was higher in EVT group than in BMM group.

CONCLUSION

Compared with BMM, EVT may improve functional outcomes in patients with ASPECTS 3-5, despite being associated with an increased risk of sICH and any ICH.

Mechanical Thrombectomy for Large Ischemic Stroke: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

There is growing evidence for endovascular thrombectomy (EVT) in patients with large ischemic core infarct and large vessel occlusion (LVO). The objective of this study was to compare the efficacy and safety of EVT vs medical management (MM) using a systematic review and meta-analysis of observational studies and randomized controlled trials (RCTs).

METHODS

We searched the PubMed, Embase, Cochrane Library, and Web of Science databases to obtain articles related to mechanical thrombectomy for large ischemic core from inception until February 10, 2023. The primary outcome was independent ambulation (modified Rankin Scale [mRS] 0-3). Effect sizes were computed as risk ratio (RR) with random-effect or fixed-effect models. The quality of articles was evaluated through the Cochrane risk assessment tool and the Newcastle-Ottawa Scale. This study was registered in PROSPERO (CRD42023396232).

RESULTS

A total of 5,395 articles were obtained through the search and articles that did not meet the inclusion criteria were excluded by review of the title, abstract, and full text. Finally, 3 RCTs and 10 cohort studies met the inclusion criteria. The RCT analysis showed that EVT improved the 90-day functional outcomes of patients with large ischemic core with high-quality evidence, including independent ambulation (mRS 0-3: RR 1.78, 95% CI 1.28-2.48, p < 0.001) and functional independence (mRS 0-2: RR 2.59, 95% CI 1.89-3.57, p < 0.001), but without significantly increasing the risk of symptomatic intracranial hemorrhage (sICH: RR 1.83, 95% CI 0.95-3.55, p = 0.07) or early mortality (RR 0.95, 95% CI 0.78-1.16, p = 0.61). Analysis of the cohort studies showed that EVT improved functional outcomes of patients without an increase in the incidence in sICH.

DISCUSSION

This systematic review and meta-analysis indicates that in patients with LVO stroke with a large ischemic core, EVT was associated with improved functional outcomes over MM without increasing sICH risk. The results of ongoing RCTs may provide further insight in this patient population.

Calculated plasma volume status is associated with poor outcomes in acute ischemic stroke treated with endovascular treatment

Background and purpose

The impact of calculated plasma volume status (PVS) on the prognosis of acute ischemic stroke treated with endovascular treatment (EVT) remains undetermined. This study aimed to investigate the association between PVS and 90 days functional outcomes after EVT.

Methods

We enrolled patients treated with EVT in the anterior circulation from a prospective registry. The endpoint was a modified Rankin scale score of ≥3 points at 90 days after EVT. We used multivariable logistic regression models to investigate the association between PVS and poor outcomes. We used the restricted cubic spline to present the linearity between PVS and poor outcomes.

Results

Among the 187 enrolled patients (median age, 65 years; 35.8% women), a total of 81 patients (43.3%) experienced poor outcomes at 90 days. In multivariable analyses, PVS was associated with poor outcomes despite increasing confounding factors (odds ratio, 3.157; 95% confidence interval, 1.942-5.534; P < 0.001). The restricted cubic spline revealed a positive correlation between PVS and the risk of poor outcomes after EVT (P for nonlinearity = 0.021).

Conclusion

Our study found that an elevated PVS value was associated with poor outcomes after EVT. Further prospective cohorts were warranted to evaluate the utility of PVS in AIS treated with EVT.

Tmax Mismatch Ratio to Identify Intracranial Atherosclerotic Stenosis-Related Large-Vessel Occlusion Before Endovascular Therapy

Background We aimed to clarify which time-to-maximum of the tissue residue function (Tmax) mismatch ratio is useful in predicting anterior intracranial atherosclerotic stenosis (ICAS)-related large-vessel occlusion (LVO) before endovascular therapy. Methods and Results Patients with ischemic stroke who underwent perfusion-weighted imaging before endovascular therapy for anterior intracranial LVO were divided into those with ICAS-related LVO and those with embolic LVO. Tmax ratios of >10 s/>8 s, >10 s/>6 s, >10 s/>4 s, >8 s/>6 s, >8 s/>4 s, and >6 s/>4 s were considered Tmax mismatch ratios. Binominal logistic regression was used to identify ICAS-related LVO, and the adjusted odds ratio (aOR) and 95% CI for each Tmax mismatch ratio increase of 0.1 were calculated. A similar analysis was performed for ICAS-related LVO with and without embolic sources, using embolic LVO as the reference. Of 213 patients (90 women [42.0%]; median age, 79 years), 39 (18.3%) had ICAS-related LVO. The aOR (95% CI) per 0.1 increase in Tmax mismatch ratio in ICAS-related LVO with embolic LVO as reference was lowest with Tmax mismatch ratio >10 s/>6 s (0.56 [0.43-0.73]). Multinomial logistic regression analysis also showed the lowest aOR (95% CI) per 0.1 increase in Tmax mismatch ratio with Tmax >10 s/>6 s (ICAS-related LVO without embolic source: 0.60 [0.42-0.85]; ICAS-related LVO with embolic source: 0.55 [0.38-0.79]). Conclusions A Tmax mismatch ratio of >10 s/>6 s was the optimal predictor of ICAS-related LVO compared with other Tmax profiles, with or without an embolic source before endovascular therapy. Registration clinicaltrials.gov. Identifier NCT02251665.

Safety outcomes of early initiation of antithrombotic agents within 24 h after intravenous alteplase at 0.6 mg/kg

BACKGROUND

We examined outcome of acute ischemic stroke (AIS) with administration of antithrombotics within 24 h after intravenous low-dose alteplase.

METHODS

Consecutive AIS patients who were treated with intravenous alteplase at 0.6 mg/kg from 2005 to 2021 were retrospectively included in our single-center registry. Patients were classified into two groups: those who received antithrombotics within 24 h after intravenous alteplase (early initiation group) and those who did not (control group). Safety outcomes were any intracranial hemorrhage (ICH), symptomatic ICH (sICH) within 36 h after onset, and death within 3 months. sICH was defined as any ICH with a ≥ 4-point increase in the National Institutes of Health Stroke Scale (NIHSS) score or death within 36 h.

RESULTS

Of 1111 patients (women, 426; median age, 76 [interquartile range, 69-83] years; median NIHSS score, 11 [6-19]; cardioembolism, 580 [52.2%]), early initiation group comprised 58 patients (22; 72 [65-80] years; 7 [4-12]; 11 [19.0%]) and control group comprised 1053 patients (404; 77 [69-84] years; 11 [6-19]; 569 [54.1%]). No significant between-group differences were observed in the incidence of any ICH (17.2% vs. 21.6%; adjusted odds ratio [aOR], 1.18; 95% confidence interval [CI], 0.57-2.44), sICH (0% vs. 0.9%, P = 1.00), or death within 3 months (5.2% vs. 6.7%; aOR, 1.23; 95% CI, 0.36-4.23).

CONCLUSIONS

Early initiation of antithrombotics after intravenous alteplase at 0.6 mg/kg did not increase the rate of sICH or death within 3 months and may be used with caution in patients with advanced neurological deterioration.

Stent Retriever or Aspiration Catheter Alone vs Their Combination as the First-Line Thrombectomy in Acute Stroke

BACKGROUND

The single-device simplicity for mechanical thrombectomy (MT) is now challenged by the complementary efficacy of dual-device first-line with a stent retriever and an aspiration catheter.

OBJECTIVE

To compare the outcomes after MT initiated with a single device vs dual devices in acute anterior circulation large vessel occlusion.

METHODS

Patients who underwent MT for acute internal carotid artery (ICA) or M1 occlusion between 2015 and 2020 were retrospectively analyzed. We divided patients into 2 groups: single-device first-line, defined as patients who underwent first-device pass with either a stent retriever or aspiration catheter, and dual-device first-line, defined as first-device pass with both devices.

RESULTS

One hundred forty-one patients were in the single-device group, and 119 were in the dual-device group. In the dual-device group, coiling or kinking of the extracranial ICA was more frequent ( P = .07) and the guide catheters were less frequently navigated to the ICA ( P < .001). 37% of the single-device group was converted to dual-device use. The proportions of mTICI ≥ 2c after the first pass were similar (33% vs 32%. adjusted odds ratio 0.91, 95% CI 0.51-1.62). An mRS score of 0 to 2 at 3 months was achieved similarly (53% vs 48%, P = .46). The total cost for thrombectomy devices was lower in the single-device group ( P < .001).

CONCLUSION

The proportions of first-pass mTICI ≥ 2c were not different between the 2 groups with similar functional outcomes, although the dual-device group more likely to have unfavorable vascular conditions.

Smaller baseline subcortical infarct volume predicts good outcomes in patients with a large core in early acute ischemic stroke after endovascular treatment

Background

Patients with acute ischemic stroke (AIS) and a large core may benefit from endovascular treatment (EVT) in the early time window.

Purpose

To examine the prognostic factors for good outcomes in patients with a large core (70-130 ml) after EVT.

Materials and methods

We retrospectively reviewed 40 patients who met the criteria from October 2019 to April 2021. Based on the modified Rankin Score (mRS) at 90 days, the patients were divided into a good outcome group (mRS 0-2) and a poor outcome group (mRS 3-6). Baseline and procedural characteristics were collected for unilateral and multivariate regression analyses to explore the factors that influence good outcomes. In particular, the infarct territories were quantified as subcortical infarct volume (SIV) and cortical infarct volume (CIV).

Results

Of the 40 patients included, good outcomes were observed in 11 (27.5%) patients. Younger age, smaller SIV and larger mismatch volume were noted in the good outcome group than in the poor outcome group (all P < 0.05). Multivariate logistic regression analysis showed that only a smaller SIV [odds ratio (OR) 0.801; 95% CI 0.644-0.996; P = 0.046] was an independent predictor for good outcomes. The receiver operating characteristic curve indicated a moderate value of SIV for predicting good outcomes, with an area under the receiver operating characteristic curve of 0.735 (95% CI 0.572-0.862; P = 0.007).

Conclusion

Subcortical infarct volume was a potential useful predictor of good outcomes in patients with a large core after EVT in the early time window.

Clinical Impact and Predictors of Diffusion Weighted Imaging (DWI) Reversal in Stroke Patients with Diffusion Weighted Imaging Alberta Stroke Program Early CT Score 0-5 Treated by Thrombectomy : Diffusion Weighted Imaging Reversal in Large Volume Stroke

PURPOSE

To determine whether reversal of DWI lesions (DWIr) on the DWI-ASPECTS (diffusion weighted imaging Alberta Stroke Program CT Score) template should serve as a predictor of 90-day clinical outcome in acute ischemic stroke (AIS) patients with pretreatment diffusion-weighted imaging (DWI)-ASPECTS 0-5 treated with thrombectomy, and to determine its predictors in current practice.

METHODS

We analyzed data of all consecutive patients included in the prospective multicenter national Endovascular Treatment in Ischemic Stroke Registry between 1 January 2015 and 31 December 2020 with a premorbid mRS ≤ 2, who presented with a pretreatment DWI-ASPECTS 0-5 score, underwent thrombectomy and had an available 24 h post-interventional MRI follow-up. Multivariable analyses were performed to evaluate the clinical impact of DWIr on early neurological improvement (ENI), 3‑month modified Rankin scale (mRS) score distribution (shift analysis) and to define independent predictors of DWIr.

RESULTS

Early neurological improvement was detected in 82/211 (41.7%) of patients while 3‑month functional independence was achieved by 75 (35.5%) patients. The DWI reversal (39/211, 18.9%) resulted an independent predictor of both ENI (aOR 3.6, 95% CI 1.2-7.7; p 0.018) and 3‑month clinical outcome (aOR for mRS shift: 2.2, 95% CI 1-4.6; p 0.030). Only successful recanalization (mTICI 2c-3) independently predicted DWIr in the studied population (aOR 3.3, 95% CI 1.3-7.9; p 0.009).

CONCLUSION

The DWI reversal occurs in a non-negligible proportion of DWI-ASPECTS 0-5 patients subjected to thrombectomy and significantly influences clinical outcome. The mTICI 2c-3 recanalization emerged as an independent DWIr predictor.

Association of Endovascular Thrombectomy With Functional Outcome in Patients With Acute Stroke With a Large Ischemic Core

BACKGROUND AND OBJECTIVES

Endovascular thrombectomy (EVT) is effective for patients with large vessel occlusion (LVO) stroke with smaller volumes of CT perfusion (CTP)-defined ischemic core. However, the benefit of EVT is unclear in those with a core volume >70 mL. We aimed to compare outcomes of EVT and non-EVT patients with an ischemic core volume ≥70 mL, hypothesizing that there would be a benefit from EVT for fair outcome (3-month modified Rankin scale [mRS] 0-3) after stroke.

METHODS

A retrospective analysis of patients enrolled into a multicenter (Australia, China, and Canada) registry (2012-2020) who underwent CTP within 24 hours of stroke onset and had a baseline ischemic core volume ≥70 mL was performed. The primary outcome was the estimation of the association of EVT in patients with core volume ≥70 mL and within 70-100 and ≥100 mL subgroups with fair outcome.

RESULTS

Of the 3,283 patients in the registry, 299 had CTP core volume ≥70 mL and 269 complete data (135 had core volume between 70 and 100 mL and 134 had core volume ≥100 mL). EVT was performed in 121 (45%) patients. EVT-treated patients were younger (median 69 vs 75 years; p = 0.011), had lower prestroke mRS, and smaller median core volumes (92 [79-116.5] mL vs 105.5 [85.75-138] mL, p = 0.004). EVT-treated patients had higher odds of achieving fair outcome in adjusted analysis (30% vs 13.9% in the non-EVT group; adjusted odds ratio [aOR] 2.1, 95% CI 1-4.2, p = 0.038). The benefit was seen predominantly in those with 70-100 mL core volume (71/135 [52.6%] EVT-treated), with 54.3% in the EVT-treated vs 21% in the non-EVT group achieving a fair outcome (aOR 2.5, 95% CI 1-6.2, p = 0.005). Of those with a core volume ≥100 mL, 50 of the 134 (37.3%) underwent EVT. Proportions of fair outcome were very low in both groups (8.1% vs 8.7%; p = 0.908).

DISCUSSION

We found a positive association of EVT with the 3-month outcome after stroke in patients with a baseline CTP ischemic core volume 70-100 mL but not in those with core volume ≥100 mL. Randomized data to confirm these findings are required.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that EVT is associated with better motor outcomes 3 months after CTP-defined ischemic stroke with a core volume of 70-100 mL.

Intravenous Thrombolysis With Alteplase at 0.6 mg/kg in Patients With Ischemic Stroke Taking Direct Oral Anticoagulants

Background

We elucidated the safety of treatment with alteplase at 0.6 mg/kg within 24 hours for patients on direct oral anticoagulants (DOACs) before ischemic stroke onset.

Methods and Results

Consecutive patients with acute ischemic stroke who underwent intravenous thrombolysis using alteplase at 0.6 mg/kg from 2011 to 2021 were enrolled from our single‐center prospective stroke registry. We compared outcomes between patients taking DOACs and those not taking oral anticoagulants within 48 hours of stroke onset. The primary safety outcome was the rate of symptomatic intracranial hemorrhage with a ≥4‐point increase on the National Institutes of Health Stroke Scale score from baseline. The efficacy outcome was defined as 3‐month modified Rankin Scale score of 0 to 2 after stroke onset. Of 915 patients with acute ischemic stroke who received intravenous thrombolysis (358 women; median age, 76 years; median National Institutes of Health Stroke Scale score, 10), 40 patients took DOACs (6 took dabigatran, 8 took rivaroxaban, 16 took apixaban, and 10 took edoxaban) within 24 hours of onset and 753 patients did not take any oral anticoagulants. The rate of symptomatic intracranial hemorrhage was comparable between patients on DOACs and those not on oral anticoagulants (2.5% versus 2.4%, P=0.95). The rate of favorable outcomes was comparable between the 2 groups (59.4% versus 58.2%, P=0.46), although the admission National Institutes of Health Stroke Scale score was higher in patients on DOACs. No significant differences showed in any intracranial hemorrhage within 36 hours or mortality at 3 months.

Conclusions

Intravenous thrombolysis would be safely performed for patients on DOACs following the recommendations of the Japanese guidelines.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02251665.

Impact on Clinical Outcomes of Changes in the Practice of Mechanical Thrombectomy due to the COVID-19 Pandemic

Objective

To evaluate whether changes in the practice of mechanical thrombectomy could affect the clinical outcomes during the coronavirus disease (COVID-19) pandemic.

Methods

Patients who underwent mechanical thrombectomy from April 2019 to March 2021 for anterior circulation proximal large artery occlusion in our institute were divided into two groups of pre- and post-COVID-19, with April 2020 assumed to be the start of the COVID-19 era with the first declaration of a state of emergency. We compared patient characteristics, proportions of patient selection depending on rapid processing of perfusion and diffusion (RAPID) CT perfusion, outcomes including treatment variables such as time and reperfusion status, and patient independence at 3 months.

Results

Data for 112 patients (median age, 79 years; 44 females) were included in the analysis. A total of 50 patients were assigned to the pre-COVID-19 group (45%). More patients were selected with RAPID CT perfusion in the post-COVID-19 compared with the pre-COVID-19 (69% vs. 16%; P <0.001). Treatment details and clinical outcomes did not differ between the groups, including the door-to-puncture time (median [interquartile range], 66 [54-90] min vs. 74 [61-89] min; P = 0.15), proportions of significant reperfusion (82% vs. 87%; P = 0.60), and modified Rankin scale score of ≤2 at 3 months (46% vs. 45%; P >0.99). Multivariate logistic regression analysis for the clinical outcome of modified Rankin scale score of ≤2 at 3 months was performed and included the following factors: age, sex, the onset-to-door time, significant reperfusion, and pre- and post-COVID-19. The treatment period did not influence the outcomes (post-COVID-19 group, odds ratio, 0.79; 95% confidence interval, 0.34-1.85, P = 0.59).

Conclusion

In the setting of a limited access to emergency MRI during the COVID-19 pandemic, RAPID CT perfusion was performed significantly more often. Changes in the practice of mechanical thrombectomy with the protected code stroke did not bring the different level of treatment and clinical outcomes as before.

MRI whole-lesion texture analysis on ADC maps for the prognostic assessment of ischemic stroke

Background

This study aims is to explore whether it is feasible to use magnetic resonance texture analysis (MRTA) in order to distinguish favorable from unfavorable function outcomes and determine the prognostic factors associated with favorable outcomes of stroke.

Methods

The retrospective study included 103 consecutive patients who confirmed unilateral anterior circulation subacute ischemic stroke by computed tomography angiography between January 2018 and September 2019. Patients were divided into favorable outcome (modified Rankin scale, mRS ≤ 2) and unfavorable outcome (mRS > 2) groups according to mRS scores at day 90. Two radiologists manually segmented the infarction lesions based on diffusion-weighted imaging and transferred the images to corresponding apparent diffusion coefficient (ADC) maps in order to extract texture features. The prediction models including clinical characteristics and texture features were built using multiple logistic regression. A univariate analysis was conducted to assess the performance of the mean ADC value of the infarction lesion. A Delong’s test was used to compare the predictive performance of models through the receiver operating characteristic curve.

Results

The mean ADC performance was moderate [AUC = 0.60, 95% confidence interval (CI) 0.49–0.71]. The texture feature model of the ADC map (tADC), contained seven texture features, and presented good prediction performance (AUC = 0.83, 95%CI 0.75–0.91). The energy obtained after wavelet transform, and the kurtosis and skewness obtained after Laplacian of Gaussian transformation were identified as independent prognostic factors for the favorable stroke outcomes. In addition, the combination of the tADC model and clinical characteristics (hypertension, diabetes mellitus, smoking, and atrial fibrillation) exhibited a subtly better performance (AUC = 0.86, 95%CI 0.79–0.93; P > 0.05, Delong’s).

Conclusion

The models based on MRTA on ADC maps are useful to evaluate the clinical function outcomes in patients with unilateral anterior circulation ischemic stroke. Energy obtained after wavelet transform, kurtosis obtained after Laplacian of Gaussian transform, and skewness obtained after Laplacian of Gaussian transform were identified as independent prognostic factors for favorable stroke outcomes.

Internal Carotid Artery Tortuosity: Impact on Mechanical Thrombectomy

Background:

Although tortuosity of the internal carotid artery (ICA) can pose a significant challenge when performing mechanical thrombectomy, few studies have examined the impact of ICA tortuosity on mechanical thrombectomy outcomes.

Methods:

In a registry-based hospital cohort, consecutive patients with anterior circulation stroke in whom mechanical thrombectomy was attempted were divided into 2 groups: those with tortuosity in the extracranial or cavernous ICA (tortuous group) and those without (nontortuous group). The extracranial ICA tortuosity was defined as the presence of coiling or kinking. The cavernous ICA tortuosity was defined by the posterior deflection of the posterior genu or the shape resembling Simmons-type catheter. Outcomes included first pass effect (FPE; extended Thrombolysis in Cerebral Infarction score 2c/3 after first pass), favorable outcome (3-month modified Rankin Scale score of 0–2), and intracranial hemorrhage.

Results:

Of 370 patients, 124 were in the tortuous group (extracranial ICA tortuosity, 35; cavernous ICA tortuosity, 70; tortuosity at both sites, 19). The tortuous group showed a higher proportion of women and atrial fibrillation than the nontortuous group. FPE was less frequently achieved in the tortuous group than the nontortuous group (21% versus 39%; adjusted odds ratio, 0.45 [95% CI, 0.26–0.77]). ICA tortuosity was independently associated with the longer time from puncture to extended Thrombolysis in Cerebral Infarction ≥2b reperfusion (β=23.19 [95% CI, 13.44–32.94]). Favorable outcome was similar between groups (46% versus 48%; P=0.87). Frequencies of any intracranial hemorrhage (54% versus 42%; adjusted odds ratio, 1.61 [95% CI, 1.02–2.53]) and parenchymal hematoma (11% versus 6%; adjusted odds ratio, 2.41 [95% CI, 1.04–5.58]) were higher in the tortuous group. In the tortuous group, the FPE rate was similar in patients who underwent combined stent retriever and contact aspiration thrombectomy and in those who underwent either procedure alone (22% versus 19%; P=0.80). However, in the nontortuous group, the FPE rate was significantly higher in patients who underwent combined stent retriever and contact aspiration (52% versus 35%; P=0.02).

Conclusions:

ICA tortuosity was independently associated with reduced likelihood of FPE and increased risk of postmechanical thrombectomy intracranial hemorrhage.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02251665.

Mechanical Thrombectomy in Patients with a Large Ischemic Volume at Presentation: Systematic Review and Meta-Analysis

The benefits of mechanical thrombectomy (MT) for patients with acute ischemic stroke (AIS) and a large ischemic core (LIC) at presentation are uncertain. We aimed to obtain up-to-date aggregate estimates of the outcomes following MT in patients with volumetrically assessed LIC. We conducted a Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)-conformed, PROSPERO-registered, systematic review and meta-analysis of studies that included patients with AIS and a baseline LIC treated with MT, reported ischemic core volume quantitatively, and included patients with a LIC defined as a core volume ≥50 mL. The search was restricted to studies published between January 2015 and June 2020. Random-effects-meta-analysis was used to assess the effect of MT on 90-day unfavorable outcome (i.e., modified Rankin Scale [mRS] 3–6), mortality, and symptomatic intracranial hemorrhage (sICH) occurrence. Sensitivity analyses were performed for imaging-modality (computed tomography-perfusion or magnetic resonance-diffusion weighted imaging) and LIC-definition (≥50 or ≥70 mL). We analyzed 10 studies (954 patients), including six (682 patients) with a control group, allowing to compare 332 patients with MT to 350 who received best-medical-management alone. Overall, after MT the rate of patients with mRS 3–6 at 90 days was 74% (99% confidence interval [CI], 67 to 84; Z-value=7.04; I²=92.3%) and the rate of 90-day mortality was 36% (99% CI, 33 to 40; Z-value=–7.07; I²=74.5). Receiving MT was associated with a significant decrease in mRS 3–6 odds ratio (OR) 0.19 (99% CI, 0.11 to 0.33; P<0.01; Z-value=–5.92; I²=62.56) and in mortality OR 0.60 (99% CI, 0.34 to 1.06; P=0.02; Z-value=–2.30; I²=58.72). Treatment group did not influence the proportion of patients experiencing sICH, OR 0.96 (99% CI, 0.2 to 1.49; P=0.54; Z-value=–0.63; I²=64.74). Neither imaging modality for core assessment, nor LIC definition influenced the aggregated outcomes. Using aggregate estimates, MT appeared to decrease the risk of unfavorable functional outcome in patients with a LIC assessed volumetrically at baseline.

Role of Apparent Diffusion Coefficient Gradient Within Diffusion Lesions in Outcomes of Large Stroke After Thrombectomy

BACKGROUND AND PURPOSE

The outcome of endovascular treatment in stroke patients with a large ischemic core is not always satisfactory. We evaluated whether the severity of baseline diffusion-weighted imaging abnormalities, as assessed by different apparent diffusion coefficient (ADC) thresholds, correlates with the clinical outcome in these patients after successful endovascular treatment.

METHODS

In 82 consecutive patients with a large vessel occlusion in the anterior circulation admitted ≤24 hours after onset, a baseline diffusion lesion volume (ADC ≤620×10^-6 mm²/s [ADC₆₂₀]) ≥50 mL and successful recanalization by endovascular treatment were retrospectively investigated. Lesion volumes of 3 ADC thresholds (ADC₆₂₀, ADC ≤520×10^-6 mm²/s [ADC₅₂₀], and ADC ≤540×10^-6 mm²/s [ADC₅₄₀]) were measured using an automated Olea software program. The performance of the ADC₅₂₀/ADC₆₂₀ and ADC₅₄₀/ADC₆₂₀ ratios in predicting the functional outcome was assessed by receiver operating characteristic curve analysis. The ADC ratio with optimal threshold showing better receiver operating characteristic performance was dichotomized at its median value into low versus high subgroup and its association with the outcome subsequently evaluated in a multivariable logistic regression model.

RESULTS

The median baseline diffusion lesion volume was 80.8 mL (interquartile range, 64.4-105.4). A good functional outcome (modified Rankin Scale score, ≤2) was achieved in 35 patients (42.7%). The optimal threshold for predicting the functional outcome was identified as ADC₅₄₀/ADC₆₂₀ (area under the curve, 0.833) and dichotomized at 0.674. After adjusting for age, baseline National Institutes of Health Stroke Scale score, intravenous tissue-type plasminogen activator, baseline diffusion lesion volume, and onset-to-recanalization time, a low ADC₅₄₀/ADC₆₂₀ was independently associated with a good functional outcome (adjusted odds ratio, 10.72 [95% CI, 3.06-37.50]; P<0.001).

CONCLUSIONS

A low ADC₅₄₀/ADC₆₂₀, which may reflect less severe ischemic stress inside a diffusion lesion, may help to identify patients who would benefit from endovascular treatment despite having a large ischemic core.

RNF213 p.R4810K (c.14429G > A) Variant Determines Anatomical Variations of the Circle of Willis in Cerebrovascular Disease

Introduction

Dysregulation of the RING finger protein 213 (RNF213) gene impairs vascular formation in experimental animal models. In addition, vascular abnormalities in the circle of Willis are associated with cerebrovascular disease. Here, we evaluated the relationship between the East Asian founder variant RNF213 p.R4810K and consequent anatomical variations in the circle of Willis in cerebrovascular disease.

Patients and Methods

The present study is an observational cross-sectional study. It included patients with acute anterior circulation non-cardioembolic stroke admitted to our institution within 7 days of symptom onset or last-known-well from 2011 to 2019, and those who participated in the National Cerebral and Cardiovascular Center Biobank. We compared anatomical variations of the vessels constituting the circle of Willis between RNF213 p.R4810K (c.14429G > A) variant carriers and non-carriers using magnetic resonance angiography and assessed the association between the variants and the presence of the vessels constituting the circle of Willis. Patients with moyamoya disease were excluded.

Results

Four hundred eighty-one patients [146 women (30%); median age 70 years; median baseline National Institutes of Health Stroke Scale score 5] were analyzed. The RNF213 p.R4810K variant carriers (n = 25) were more likely to have both posterior communicating arteries (PComAs) than the variant non-carriers (n = 456) (56% vs. 13%, P < 0.01). Furthermore, variant carriers were less likely to have an anterior communicating artery (AComA) than non-carriers (68% vs. 84%, P = 0.04). In a multivariate logistic regression analysis, the association of RNF213 p.R4810K variant carriers with the presence of both PComAs and the absence of AComA remained significant.

Conclusion

Our findings suggest that the RNF213 p.R4810K variant is an important factor in determining anatomical variations in the circle of Willis.

Acute Stroke Imaging Research Roadmap IV: Imaging Selection and Outcomes in Acute Stroke Clinical Trials and Practice

BACKGROUND AND PURPOSE

The Stroke Treatment Academic Industry Roundtable (STAIR) sponsored an imaging session and workshop during the Stroke Treatment Academic Industry Roundtable XI via webinar on October 1 to 2, 2020, to develop consensus recommendations, particularly regarding optimal imaging at primary stroke centers.

METHODS

This forum brought together stroke neurologists, neuroradiologists, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke, industry representatives, and members of the US Food and Drug Administration to discuss imaging priorities in the light of developments in reperfusion therapies, particularly in an extended time window, and reinvigorated interest in brain cytoprotection trials.

RESULTS

The imaging session summarized and compared the imaging components of recent acute stroke trials and debated the optimal imaging strategy at primary stroke centers. The imaging workshop developed consensus recommendations for optimizing the acquisition, analysis, and interpretation of computed tomography and magnetic resonance acute stroke imaging, and also recommendations on imaging strategies for primary stroke centers.

CONCLUSIONS

Recent positive acute stroke clinical trials have extended the treatment window for reperfusion therapies using imaging selection. Achieving rapid and high-quality stroke imaging is therefore critical at both primary and comprehensive stroke centers. Recommendations for enhancing stroke imaging research are provided.

Blind Exchange With Mini-Pinning Technique Using the Tron Stent Retriever for Middle Cerebral Artery M2 Occlusion Thrombectomy in Acute Ischemic Stroke

Introduction: The usefulness of the blind exchange with mini-pinning (BEMP) technique has recently been reported for mechanical thrombectomy in patients with stroke owing to medium vessel occlusion (MeVO). The Tron stent retriever can be delivered and deployed through a 0.0165-inch microcatheter. This retriever has potential as an effective and safe treatment for acute ischemic stroke (AIS) due to occlusion of the M2 segment of the middle cerebral artery (MCA). Here, we report the outcomes of the BEMP technique using Tron stent retrievers for M2 occlusion thrombectomy.

Methods: Consecutive patients with AIS owing to M2 occlusion who underwent the BEMP technique using 2 × 15-mm or 4 × 20-mm Tron stent retrievers were included. The technique involves deploying a Tron stent retriever through a 0.0165-inch microcatheter, followed by microcatheter removal and blind navigation of a 3MAX or 4MAX aspiration catheter over the bare Tron delivery wire until the aspiration catheter reaches the clot. A Tron stent retriever is inserted into the aspiration catheter like a cork and subsequently pulled as a unit. We assessed procedural outcomes [first-pass expanded thrombolysis in cerebral infarction (eTICI) score 2c/3 and 2b/2c/3], safety outcomes [symptomatic intracranial hemorrhage (sICH)], and clinical outcomes (good outcome rate defined as modified Rankin Scale score 0–2 at 90 days and mortality at 90 days).

Results: Eighteen M2 vessels were treated in 15 patients (six female, median age: 80 years, and median National Institutes of Health Stroke Scale score: 18). The BEMP technique was performed successfully in all cases. Whether to use a 3MAX or 4MAX catheter was determined by considering one of the following target vessels: dominant, non-dominant, or co-dominant M2 (3MAX, n = 9; 4MAX, n = 9). The first-pass eTICI 2c/3 and 2b/2c/3 rates were 47 (7/15) and 60% (9/15), respectively; sICH was not observed. Seven patients (47%) achieved good outcomes, and one patient (7%) died within 90 days.

Conclusions: The Tron stent retriever was safely and effectively used in the BEMP technique for acute MCA M2 occlusion and can be combined with a 0.0165-inch microcatheter, which may be useful for treating MeVO, in general.