Triage imaging and outcome measures for large core stroke thrombectomy – a systematic review and meta-analysis

Endovascular therapy in patients with a large ischemic volume at presentation: An aggregate patient-level analysis

INTRODUCTION

Recently, four randomized controlled trials (RCTs) have demonstrated the benefits of mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) caused by anterior large vessel occlusion (LVO) and a large ischemic core at baseline (LIC). The purpose of this study was to investigate the features influencing the clinical outcome and the benefits of mechanical thrombectomy in this subgroup.

METHODS

We conducted a multicenter retrospective aggregate cohort study of patients with AIS-LVO and a LIC, assessed with quantitative core volume measures, treated with MT between 2012 and 2019. The data were queried through four registries, including patients with core volumes ≥50cc. Multivariable logistic regression models were employed to determine factors independently associated with clinical outcomes in patients with successful recanalization (modified-Thrombolysis-in-Cerebral-Infarction-score, mTICI=2b-3) and unsuccessful recanalization group (mTICI=0-2a). The primary endpoint was a favorable functional outcome at day-90, defined as a modified Rankin scale (mRS) of 0-3, accounting for the inherent severity of AIS with baseline LIC. Secondary outcomes included functional independence (mRS 0-2) at day-90, mortality, and symptomatic Intracranial Hemorrhage (sICH).

RESULTS

A total of 460 patients were included (mean age 66±14.2 years; 39.6 % females). The mean baseline NIHSS was 20±5.2, and the core volume was 103.2±54.6 ml. Overall, 39.8 % (183/460) of patients achieved a favorable outcome at day-90 (mRS 0-3). Successful recanalization was significantly associated with a more frequent favorable outcome (aOR, 4.79; 95 %CI, 2.73-8.38; P<0.01) and functional independence (P<0.01). This benefit remained significant in older patients and in patients with cores above 100cc. At 90 days, 147/460 patients (32 %) were deceased, with successful recanalization significantly associated with less frequent mortality (OR, 0.34; 95 %CI, 0.22-0.53; P<0.01). The rate of sICH was 17.4 % and did not differ significantly between groups.

CONCLUSIONS

In this large, pooled-cohort study of AIS-LVO patients with infarct cores over 50cc at baseline, we demonstrated that successful recanalization was associated with a better functional outcome, lower mortality, and similar rates of symptomatic intracranial hemorrhage for a wide spectrum of patients.

Endovascular thrombectomy for ischemic stroke with large infarct, short- and long-term outcomes: a meta-analysis of 6 randomised control trials

Endovascular Thrombectomy (EVT) as first-line treatment of patients with large core ischemic infarct is a subject of debate. A systematic literature search was conducted in four electronic databases for randomized control trials (RCTs) comparing EVT to best medical treatment (BMT) for large core infarcts (ASPECTS ≤ 5). Relevant studies were added after screening for titles, abstracts, and complete text. Meta-analysis was performed. The continuous outcomes were analyzed using the standardized mean difference (SMD) and 95% CI, while the binary outcomes were analyzed using the risk ratio (RR) and 95% confidence interval (CI). A funnel plot was used to visually evaluate publication bias, and if feasible, Egger's test was used to validate. We included 1918 patients from six RCTs that compared EVT plus BMT and BMT alone in patients with large core infarct due to large vessel occlusion in the anterior circulation. There were 946 patients in the EVT group and 972 patients in the BMT group. The one-year outcomes are available for 314 patients in the EVT group and 292 patents in the BMT group from two RCTs. EVT group had statistically significant higher rate of 90-day mRS 0-1 (RR = 3.1, P-value < 0.0001), mRS 0-2 (RR = 2.64, P-value < 0.0001), mRS 0-3 (RR = 1.80, P-value < 0.0001), lower 90-day mean mRS score (SMD = -0.29, P-value < 0.0001), lower 90-day mortality rate (RR = 0.85, P-value = 0.015), and greater early neurological improvement (RR = 2.16, P-value < 0.00001) compared to the BMT group. However, the rates of symptomatic intracerebral hemorrhage (sICH) (RR = 1.76, P-value = 0.01) and any ICH (RR = 2.18, P-value < 0.00001) were higher in EVT group. Our finding showed that EVT plus BMT led to in an absolute improvement of 5%, 12%, and 16% in 90-day mRS 0-1, 0-2, and 0-3, respectively. In addition, patients in EVT plus BMT group had a 3% increased probability of experiencing sICH and were 32% more susceptible to any ICH. Moreover, the one-year mRS 0-2 (RR = 2.16, P-value < 0.00001) and mRS 0-3 (RR = 1.80, P-value < 0.0001) was significantly favor the EVT plus BMT over BMT alone. Although, the one-year mortality rate was not significantly differed between two groups (RR = 0.91, P-value = 0.31). There was no statistically significant difference observed between the EVT plus BMT group and the BMT group concerning new stroke, decompressive craniectomy, and serious adverse events. Combined data from six RCTs shows that EVT plus BMT provides significantly better short- and long-term functional outcomes with minimal increase in symptomatic hemorrhage over BMT in patient with large core infarcts.

Earlier Endovascular Thrombectomy and Mortality in Patients with Anterior Circulation Large Vessel Occlusion: A Propensity-Matched Analysis of the Stroke Thrombectomy and Aneurysm Registry

BACKGROUND

The definitive impact of onset to arterial puncture time (OPT) on 90-day mortality after endovascular thrombectomy (EVT) in patients with acute ischemic stroke (AIS) caused by anterior circulation large vessel occlusion (LVO) remains unknown. The present study aimed to evaluate the influence of OPT on 90-day mortality in anterior circulation AIS-LVO patients who underwent EVT.

METHODS

Data from 33 international centers were retrospectively analyzed. The receiver operating characteristic curve analysis was used to identify a cutoff for OPT. A propensity score-matched analysis was performed. The primary outcome was 90-day mortality (modified Rankin Scale [mRS] 6). Secondary outcomes included mortality at discharge, 90-day good outcome (mRS 0-2), 90-day poor outcome (mRS 5-6), successful recanalization (defined as postprocedure modified Thrombolysis in Cerebral Infarction scale ≥2b), and intracranial hemorrhage.

RESULTS

A total of 2842 AIS-LVO patients with EVT were included. The cutoff for OPT for 90-day mortality was 180 min. Of these 378 patients had OPT <180 min and 378 patients had OPT ≥180 min in the propensity score-matched cohort (n = 756). Patients with OPT <180 min were less likely to have 90-day mortality (odds ratio [OR] 0.70, 95% confidence interval [CI] 0.51-0.96) and poor outcome (OR 0.71, 95% CI 0.53-0.96), and more likely to have 90-day good outcome (OR 1.55, 95% CI 1.16-2.08). Other outcomes showed no significant differences.

CONCLUSIONS

This study showed that OPT <180 min was less related to 90-day mortality and poor outcome, and more to 90-day good outcome in AIS-LVO patients who underwent EVT.

Comparison of two automated CT perfusion software packages in patients with ischemic stroke presenting within 24 h of onset

Background

We compared the ischemic core and hypoperfused tissue volumes estimated by RAPID and JLK-CTP, a newly developed automated computed tomography perfusion (CTP) analysis package. We also assessed agreement between ischemic core volumes by two software packages against early follow-up infarct volumes on diffusion-weighted images (DWI).

Methods

This retrospective study analyzed 327 patients admitted to a single stroke center in Korea from January 2021 to May 2023, who underwent CTP scans within 24 h of onset. The concordance correlation coefficient (ρ) and Bland-Altman plots were utilized to compare the volumes of ischemic core and hypoperfused tissue volumes between the software packages. Agreement with early (within 3 h from CTP) follow-up infarct volumes on diffusion-weighted imaging (n = 217) was also evaluated.

Results

The mean age was 70.7 ± 13.0 and 137 (41.9%) were female. Ischemic core volumes by JLK-CTP and RAPID at the threshold of relative cerebral blood flow (rCBF) < 30% showed excellent agreement (ρ = 0.958 [95% CI, 0.949 to 0.966]). Excellent agreement was also observed for time to a maximum of the residue function (T max) > 6 s between JLK-CTP and RAPID (ρ = 0.835 [95% CI, 0.806 to 0.863]). Although early follow-up infarct volume showed substantial agreement in both packages (JLK-CTP, ρ = 0.751 and RAPID, ρ = 0.632), ischemic core volumes at the threshold of rCBF <30% tended to overestimate ischemic core volumes.

Conclusion

JLK-CTP and RAPID demonstrated remarkable concordance in estimating the volumes of the ischemic core and hypoperfused area based on CTP within 24 h from onset.

CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core

BACKGROUND

Recent trials confirmed the effectiveness of endovascular therapy in patients with large ischemic cores. Yet the optimal neuroimaging modalities to define large core remains unclear. We tried to address this question by comparing the functional outcomes in patients receiving thrombectomy selected by either noncontrast computed tomography Alberta Stroke Program Early Computed Tomography Score (ASPECTS) or computed tomography perfusion (CTP).

METHODS

This study retrospectively selected patients enrolled in the International Stroke Perfusion Registry between August 2011 and April 2022. Patients with acute stroke with large vessel occlusion in anterior circulation treated with endovascular therapy were included. All received both CTP and noncontrast computed tomography. The primary outcome was defined as poor functional outcome represented by a modified Rankin Scale score of 5 to 6 at 3 months. Large cores were defined in terms of either (1) noncontrast computed tomography ASPECTS ≤5 or (2) core volume ≥70 mL on CTP.

RESULTS

A total of 1115 patients were included in the analysis, of which 90 patients had ASPECTS ≤5 (8.1%) and 97 patients CTP core ≥70 mL (8.7%). A fair agreement between ASPECTS and CTP with a κ value of 0.31 (0.21-0.40) was found. Compared with patients with neither CTP nor ASPECTS large cores, those with only ASPECTS-defined large cores (ie, ASPECTS ≤5; n=56) did not have a higher adjusted odds of poor outcome (29%; odds ratio, 1.84 [0.91-3.73]; P=0.089). However, patients with CTP large core but not ASPECTS-defined large core (n=63) had a higher adjusted odds of poor outcome (60%; odds ratio, 3.91 [2.01-7.60]; P<0.001). In time-stratified subgroup analysis (>6 versus ≤6 hours), ASPECTS showed no discriminative difference between ≤5 and >5 in poor outcome for patients receiving endovascular therapy within 6 hours.

CONCLUSIONS

CTP core ≥70 mL-defined large cores are more predictive of poor outcome than ASPECTS ≤5-defined core in endovascular therapy patients, particularly within 6 hours after stroke onset.

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.

Endovascular treatment for large-core ischaemic stroke: a meta-analysis of randomised controlled clinical trials

BACKGROUND AND PURPOSE

Current guidelines recommend endovascular treatment (EVT) for acute ischaemic stroke (AIS), due to large-vessel occlusion and an Alberta Stroke Program Early CT Score (ASPECTS) of ≥6. High-quality evidence resulting from randomised controlled clinical trials (RCTs) regarding EVT among large-core AIS has recently become available, justifying an updated meta-analysis aiming to evaluate efficacy and safety of EVT in this clinical setting.

METHODS

We conducted a systematic review and meta-analysis including all available RCTs that compared EVT in addition to best medical treatment (BMT) versus BMT alone for large-core AIS (defined by ASPECTS 2-5 or volumetric methods). The primary outcome was reduced disability at 3 months (≥1-point reduction across all Modified Rankin Scale (mRS) grades). Secondary outcomes included independent ambulation at 3 months (mRS score 0-3), good functional outcome at 3 months (mRS score 0-2), excellent functional outcome at 3 months (mRS score 0-1), symptomatic intracranial haemorrhage (sICH) and any intracranial haemorrhage (ICH) and mortality at 3 months. The random-effects model was used.

RESULTS

Four RCTs were included comprising a total of 662 patients treated with EVT vs 649 patients treated with BMT. Compared with BMT, EVT was significantly associated with reduced disability (common OR 1.70, 95% CI 1.39 to 2.07; I2=0%), independent ambulation (risk ratio (RR) 1.69, 95% CI 1.33 to 2.14; I2=39%) and good functional outcome (RR 2.33, 95% CI 1.76 to 3.10; I2=0%), but not with excellent functional outcome (RR 1.46, 95% CI 0.91 to 2.33; I2=39%) at 3 months. Although rates of sICH (RR 1.98, 95% CI 1.07 to 3.68; I2=0%) and any ICH (RR 2.13, 95% CI 1.70 to 2.66; I2=37%) were higher in the EVT group, 3-month mortality (RR 0.98, 95% CI 0.83 to 1.15; I2=0%) did not differ between the two groups.

CONCLUSION

EVT appears to be effective and safe and may be considered for the treatment of large-core AIS, as assessed by ASPECTS of 2-5 or volumetric methods.

PROSPERO REGISTRATION NUMBER

CRD42022334417.

Endovascular Thrombectomy for Acute Stroke with a Large Ischemic Core: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Endovascular thrombectomy (ET) efficacy and safety in stroke with a large ischemic core is still inconclusive as this population has been underrepresented in ET randomized controlled trials (RCTs).

METHODS

We conducted a systematic review and meta-analysis synthesizing RCTs, which were retrieved by systematically searching: PubMed, Web of Science, SCOPUS, and Cochrane through February 18th, 2023. Our primary outcome was neurological disability measured by the modified Rankin scale (mRS). Dichotomous outcomes were pooled using risk ratio (RR) along with confidence interval (CI) using Revman V. 5.4 software.

RESULTS

Three RCTs with a total of 1010 patients were included in our analysis. ET significantly increased the rates of functional independence (mRS ≤ 2) (RR: 2.54 with 95% CI [1.85, 3.48]), independent ambulation (mRS ≤ 3) (RR: 1.78 with 95% CI [1.28, 2.48]), and early neurological improvement (RR: 2.46 with 95% CI [1.60, 3.79]). However, there was no difference between endovascular thrombectomy and medical care in excellent neurological recovery (mRS ≤ 1) (RR: 1.35 with 95% CI [0.88, 2.08]). Also, ET significantly reduced the rate of poor neurological recovery (mRS 4-6) (RR: 0.79 with 95% CI [0.72, 0.86]). However, endovascular thrombectomy was associated with more incidence of any intracranial hemorrhage (RR: 2.40 with 95% CI [1.90, 3.01] [0.72, 0.86]).

CONCLUSION

ET combined with medical care was associated with better functional outcomes compared with medical care alone. However, ET was associated with a higher rate of intracranial hemorrhage. This can support extending ET indication in the management of stroke with a large ischemic core.

Mode of Imaging Study and Endovascular Therapy for a Large Ischemic Core: Insights From the RESCUE-Japan LIMIT

BACKGROUND AND PURPOSE

Differences in measurement of the extent of acute ischemic stroke using the Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) by non-contrast computed tomography (CT-ASPECTS stratum) and diffusion-weighted imaging (DWI-ASPECTS stratum) may impact the efficacy of endovascular therapy (EVT) in patients with a large ischemic core.

METHODS

The RESCUE-Japan LIMIT (Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism Japan-Large IscheMIc core Trial) was a multicenter, open-label, randomized clinical trial that evaluated the efficacy and safety of EVT in patients with ASPECTS of 3-5. CT-ASPECTS was prioritized when both CT-ASPECTS and DWI-ASPECTS were measured. The effects of EVT on the modified Rankin Scale (mRS) score at 90 days were assessed separately for each stratum.

RESULTS

Among 183 patients, 112 (EVT group, 53; No-EVT group, 59) were in the CT-ASPECTS stratum and 71 (EVT group, 40; No-EVT group, 31) in the DWI-ASPECTS stratum. The common odds ratio (OR) (95% confidence interval) of the EVT group for one scale shift of the mRS score toward 0 was 1.29 (0.65-2.54) compared to the No-EVT group in CT-ASPECTS stratum, and 6.15 (2.46-16.3) in DWI-ASPECTS stratum with significant interaction between treatment assignment and mode of imaging study (P=0.002). There were significant interactions in the improvement of the National Institutes of Health Stroke Scale score at 48 hours (CT-ASPECTS stratum: OR, 1.95; DWIASPECTS stratum: OR, 14.5; interaction P=0.035) and mortality at 90 days (CT-ASPECTS stratum: OR, 2.07; DWI-ASPECTS stratum: OR, 0.23; interaction P=0.008).

CONCLUSION

Patients with ASPECTS of 3-5 on MRI benefitted more from EVT than those with ASPECTS of 3-5 on CT.

Endovascular thrombectomy for the treatment of large ischemic stroke: a systematic review and meta-analysis of randomized control trials

Importance

Endovascular thrombectomy (ET) has previously been reserved for patients with small to medium acute ischemic strokes. Three recent randomized control trials (RCTs) have demonstrated functional benefit and risk profiles for ET in large volume ischemic strokes.

Objective

The primary objective of the meta-analysis was to determine the combined benefit of ET in adult patients with large volume acute ischemic strokes and to better determine the risk of adverse events following ET.

Data Sources

We systematically searched MEDLINE, EMBASE, SCOPUS, the Cochrane Central Register of Controlled, and Google Scholar for all RCTs published in English language between January 1, 2010, to February 19, 2023.

Study Selection

We included only RCTs specifically comparing ET to medical therapy in patients with acute ischemic stroke with large volume infarctions as defined by Alberta Stroke Program Early Computed Tomography Score (ASPECTS) 3-5 or calculated infarct volume of > 50-70mL. Two independent reviewers screened potential studies for full text review and metaanalysis inclusion with conflicts being resolved by consensus or third reviewer.

Data Extraction and Synthesis

Data was extracted based on pre-specified variables on study methods and design, participant characteristics, analysis approach, as well as efficacy and safety outcomes. Results were combined using a restricted maximum-likelihood estimation random-effects model. Studies were assessed for potential bias and quality of evidence.

Main Outcomes and Measures

The prespecified primary outcome was an overall ordinal shift across the range of modified Rankin scale scores toward a better outcome at 90 days following either ET or medical management for patients with large volume ischemic strokes.

Results

A total of 3044 studies were screened, and 29 underwent full text review. 3 RCTs (1011 patients) were included in the analysis. The pooled random effects model for the primary outcome of mRS improvement favored ET over medical management, generalized odds ratio 1.55 [95% CI 1.25 - 1.91, T ² = 0.01, I ² = 42.84%]. There was a trend toward increased risk of symptomatic ICH in the ET group, relative risk 1.85 [95% CI 0.94 - 3.63, T ² = 0.00, I ² = 0.00%].

Conclusions and Relevance

In patients with large volume ischemic strokes, ET has a clear functional benefit and does not confer increased risk of significant complications compared to medical management alone.

Neurological Functional Independence After Endovascular Thrombectomy and Different Imaging Modalities for Large Infarct Core Assessment : A Systematic Review and Meta-analysis

PURPOSE

To investigate the rate of neurological functional independence (NFI) at 90 days in patients with large infarct core (LIC), which was evaluated by different imaging modalities before endovascular thrombectomy (EVT).

METHODS

PubMed and EMBASE were searched for original studies on clinical functional outcomes at 90 days in LIC patients who received EVT treatment from inception to 28 September 2021. The pooled NFI rates were calculated using random effects model according to different imaging modalities and criteria.

RESULTS

We included 34 studies enrolling 2997 LIC patients. The NFI rates were 23% (95% confidence interval, CI 15-32%) and 24% (95% CI 10-38%) when LIC was defined as core volume ≥50 ml and ≥ 70 ml separately on computed tomography perfusion, 36% (95% CI 23-48%) and 21% (95% CI 17-25%) when LIC was defined as core volume ≥ 50 ml and ≥ 70 ml separately on magnetic resonance diffusion-weighted imaging (DWI), 28% (95% CI 24-32%) and 37% (95% CI 21-53%) when LIC was defined as DWI-ASPECTS ≤ 5 and ≤ 6 separately, 23% (95% CI 19-27%) and 32% (95% CI 18-46%) when LIC was defined as NCCT-ASPECTS ≤ 5 and ≤ 6 separately.

CONCLUSION

Similar NFI rates could be obtained after EVT in LIC patients if proper LIC criteria were select according to the imaging modality.

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.

Endovascular Thrombectomy Reduces Risk of Poor Functional Outcomes in Patients Presenting within 0-6 Hours with Large Ischemic Core Volumes on Computed Tomography Perfusion

INTRODUCTION

Patients presenting with large ischemic core volumes (LICVs) on computed tomography perfusion (CTP) are at high risk for poor functional outcomes. We sought to identify predictors of outcome in patients with an internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion and LICV.

METHODS

A large healthcare system's prospectively collected code stroke registry was utilized for this retrospective analysis of patients presenting within 6 hours with at least 50 ml of CTP reduced relative cerebral blood flow (CBF) < 30%. A multivariable logistic regression model was constructed to identify independent predictors (p < 0.05) of poor discharge outcome (modified Rankin scale score 4-6).

RESULTS

Over a 38-month period, we identified 104 patients meeting inclusion criteria, with a mean age of 65.4 ± 16.2 years, median presenting National Institutes of Health Stroke Scale score 20 (IQR 16-24), median ischemic core volume (CBF < 30%) 82 ml (IQR 61-118), and median mismatch volume 80 ml (IQR 56-134). Seventy-five patients (72.1%) had a discharge modified Rankin scale score of 4-6. Sixty-six of 104 (63.5%) patients were treated with endovascular thrombectomy (EVT). In the multivariable regression model, EVT (OR 0.303; 95% CI 0.080-0.985; p = 0.049) and lower blood glucose (per 1-point increase, OR 1.014; 95% CI 1.003-1.030; p = 0.030) were independently protective against poor discharge outcome.

CONCLUSIONS

EVT is independently associated with a reduced risk of poor functional outcome in patients presenting within 6 hours with ICA or MCA occlusions and LICV.

Outcomes and CT Perfusion Thresholds of Mechanical Thrombectomy for Patients With Large Ischemic Core Lesions

Objective

To explore the clinical prognosis and factors after mechanical thrombectomy (MT) in patients with large cerebral infarction assessed by computed tomographic perfusion (CTP)and the optimal threshold of cerebral blood flow (CBF) for estimating ischemic core.

Methods

We analyzed data from the anterior circulation database of our hospital (August 2018-June 2021). Multivariate logistic regression analyses identified the predictors of clinical outcomes for patients with large baseline infarcts (>50 ml) assessed by the MIStar software. The receiver operating characteristic (ROC) analysis was used to explore the cutoff value of factors.

Results

The present study included one hundred thirty-seven patients with large baseline infarcts. Moreover, 23 (16.8%) patients achieved functionally independent outcomes, and 50 (36.5%) patients died at 90 days. A total of 20 (14.7%) patients had symptomatic intracranial hemorrhage (sICH). The multivariable analysis showed that higher age and larger core volume were independent of poor outcomes. The cutoff value of core volume was 90 ml, and the age was 76 years. Hypertension and rt-PA treatment were independent factors of sICH. Higher age and larger ischemic volume were independent risk factors of mortality.

Conclusions

Mechanical thrombectomy can be applied in patients with large ischemic core volumes. Patients older than 76 years with large cores (>90 ml) are unlikely to benefit from MT. These findings may be helpful in selecting patients with large baseline infarcts to be treated by MT. The threshold of CBF < 30% is the independent factor, and this is worth evaluating in future studies to find the optimal threshold of CBF.

Randomized Clinical Trial of Endovascular Therapy for Acute Large Vessel Occlusion with Large Ischemic Core (RESCUE-Japan LIMIT): Rationale and Study Protocol

Endovascular therapy is strongly recommended for acute cerebral large vessel occlusion (LVO) with an Alberta stroke program early computed tomography score (ASPECTS) ≥6 due to occlusion of the internal carotid artery or M1 segment of the middle cerebral artery. However, the effect of endovascular therapy for patients with a large ischemic core with an ASPECTS ≤5 (0-5) was not established. A multicenter, randomized, open-label, parallel-group trial was conducted to investigate the superiority of endovascular therapy over medical therapy without endovascular therapy for a large ischemic core with ASPECTS (3-5). Patients were randomly assigned to receive endovascular therapy or without endovascular therapy at a ratio of 1:1. The primary outcome was a moderate functional outcome, defined as a modified Rankin scale (mRS; scores ranging from 0 [no symptoms] to 6 [death]) ≤3 after 90 days. The secondary outcomes were defined as ordinal mRS, good functional outcome (mRS ≤2), excellent functional outcome (mRS ≤1), mRS shift analysis after 90 days, and early improvement of neurological findings at 48 hours. A total sample size of 200 was estimated to provide a power of 0.9 with a two-sided alpha of 0.05, for the primary outcome, considering a 15% dropout rate. This randomized clinical trial reported the applicability of endovascular therapy in patients with acute cerebral LVO with a large ischemic core.

Association of Ischemic Core Imaging Biomarkers With Post-Thrombectomy Clinical Outcomes in the MR CLEAN Registry

Background: A considerable proportion of acute ischemic stroke patients treated with endovascular thrombectomy (EVT) are dead or severely disabled at 3 months despite successful reperfusion. Ischemic core imaging biomarkers may help to identify patients who are more likely to have a poor outcome after endovascular thrombectomy (EVT) despite successful reperfusion. We studied the association of CT perfusion-(CTP), CT angiography-(CTA), and non-contrast CT-(NCCT) based imaging markers with poor outcome in patients who underwent EVT in daily clinical practice.

Methods: We included EVT-treated patients (July 2016–November 2017) with an anterior circulation occlusion from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry with available baseline CTP, CTA, and NCCT. We used multivariable binary and ordinal logistic regression to analyze the association of CTP ischemic core volume, CTA-Collateral Score (CTA-CS), and Alberta Stroke Program Early CT Score (ASPECTS) with poor outcome (modified Rankin Scale score (mRS) 5-6) and likelihood of having a lower score on the mRS at 90 days.

Results: In 201 patients, median core volume was 13 (IQR 5-41) mL. Median ASPECTS was 9 (IQR 8-10). Most patients had grade 2 (83/201; 42%) or grade 3 (28/201; 14%) collaterals. CTP ischemic core volume was associated with poor outcome [aOR per 10 mL 1.02 (95%CI 1.01–1.04)] and lower likelihood of having a lower score on the mRS at 90 days [aOR per 10 mL 0.85 (95% CI 0.78–0.93)]. In multivariable analysis, neither CTA-CS nor ASPECTS were significantly associated with poor outcome or the likelihood of having a lower mRS.

Conclusion: In our population of patients treated with EVT in daily clinical practice, CTP ischemic core volume is associated with poor outcome and lower likelihood of shift toward better outcome in contrast to either CTA-CS or ASPECTS.

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.

What is the impact of head movement on automated CT perfusion mismatch evaluation in acute ischemic stroke?

OBJECTIVES

Automated CT perfusion mismatch assessment is an established treatment decision tool in acute ischemic stroke. However, the reliability of this method in patients with head motion is unclear. We therefore sought to evaluate the influence of head movement on automated CT perfusion mismatch evaluation.

METHODS

Using a realistic CT brain-perfusion-phantom, 7 perfusion mismatch scenarios were simulated within the left middle cerebral artery territory. Real CT noise and artificial head movement were added. Thereafter, ischemic core, penumbra volumes and mismatch ratios were evaluated using an automated mismatch analysis software (RAPID, iSchemaView) and compared with ground truth simulated values.

RESULTS

While CT scanner noise alone had only a minor impact on mismatch evaluation, a tendency towards smaller infarct core estimates (mean difference of -5.3 (-14 to 3.5) mL for subtle head movement and -7.0 (-14.7 to 0.7) mL for strong head movement), larger penumbral estimates (+9.9 (-25 to 44) mL and +35 (-14 to 85) mL, respectively) and consequently larger mismatch ratios (+0.8 (-1.5 to 3.0) for subtle head movement and +1.9 (-1.3 to 5.1) for strong head movement) were noted in dependence of patient head movement.

CONCLUSIONS

Motion during CT perfusion acquisition influences automated mismatch evaluation. Potentially treatment-relevant changes in mismatch classifications in dependence of head movement were observed and occurred in favor of mechanical thrombectomy.

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

BACKGROUND

We aimed to identify the large ischemic core (LIC) volume ranges in acute ischemic stroke patients that can benefit from mechanical thrombectomy (MT).

METHODS

Consecutive patients within 24 hours of onset of anterior circulation ischemic stroke with large vessel occlusion and ischemic core volumes of 70-300 mL were included from our single-center prospective database from March 2014 to December 2019. Subjects were divided into three groups by baseline ischemic core volume (A: 70-100 mL; B: 101-130 mL; C: >130 mL). We compared modified Rankin Scale (mRS) score 0-2 at 3 months and parenchymal hematoma between patients receiving MT and standard medical treatment (SMT), and determined clinically treatable core volume ranges for MT.

RESULTS

Of 157 patients (86 women; median age, 81 years; median ischemic core volume, 123 mL), 49 patients underwent MT. In Group A (n=52), MT patients (n=31) showed a higher proportion of mRS 0-2 at 3 months (52% vs 5%, P<0.05) versus SMT, respectively. Group B (n=36) MT patients (n=14) also had a higher proportion of mRS 0-2 at 3 months (29% vs 9%, P=0.13) versus SMT, respectively. In Group C (n=69), only four patients received MT. The 95% confidence intervals for the probability of mRS 0-2 at 3 months in patients with MT (n=49) versus SMT (n=108) intersected at 120-130 mL.

CONCLUSIONS

Ischemic core volumes between 70 and 100 mL may benefit from MT. The treatable upper core limit is approximately 120 mL in selected patients with LIC of 70-300 mL.

Toward a more inclusive paradigm: thrombectomy for stroke patients with pre-existing disabilities

BACKGROUND

Persons with pre-existing disabilities represent over one-third of acute stroke presentations, but account for a far smaller proportion of those receiving endovascular thrombectomy (EVT) and thrombolysis. This is despite existing ethical, economic, legal, and social directives to maximize equity for this vulnerable population. We sought to determine associations between baseline modified Rankin Scale (mRS) and outcomes after EVT.

METHODS

Individuals who underwent EVT were identified from a prospectively maintained database. Demographics, medical history, presentations, treatments, and outcomes were recorded. Baseline disability was defined as baseline mRS≥2. Accumulated disability was defined as the delta between baseline mRS and absolute 90-day mRS.

RESULTS

Of 381 individuals, 49 had baseline disability (five with mRS=4, 23 mRS=3, 21 mRS=2). Those with baseline disability were older (81 vs 68 years, P<0.0001), more likely female (65% vs 49%, P=0.032), had more coronary disease (39% vs 20%, P=0.006), stroke/TIA history (35% vs 15%, P=0.002), and higher NIH Stroke Scale (19 vs 16, P=0.001). Baseline mRS was associated with absolute 90-day mRS ≤2 (OR=0.509, 95%CI=0.370-0.700). However, baseline mRS bore no association with accumulated disability by delta mRS ≤0 (ie, return to baseline, OR=1.247, 95%CI=0.943-1.648), delta mRS ≤1 (OR=1.149, 95%CI=0.906-1.458), delta mRS ≤2 (OR 1.097, 95% CI 0.869-1.386), TICI 2b-3 reperfusion (OR=0.914, 95%CI=0.712-1.173), final infarct size (P=0.853, β=-0.014), or intracerebral hemorrhage (OR=0.521, 95%CI=0.244-1.112).

CONCLUSIONS

While baseline mRS was associated with absolute 90-day disability, there was no association with accumulated disability or other outcomes. Patients with baseline disability should not be routinely excluded from EVT based on baseline mRS alone.