Benefit from mechanical thrombectomy in acute ischemic stroke with fast and slow progression

The presence of a ghost infarct core is associated with fast core growth in acute ischemic stroke

INTRODUCTION

The overestimation of ischemic core volume by CT perfusion (CTP) is a critical concern in the selection of candidates for reperfusion therapy. This phenomenon is termed a ghost infarct core (GIC). Core growth rate (CGR) is an indicator of ischemic severity. We aimed to elucidate the association between GIC and CGR.

PATIENTS AND METHODS

Consecutive patients with acute ischemic stroke who underwent mechanical thrombectomy in our institute from March 2017 to July 2022 were enrolled. The initial ischemic core volume (IICV) was measured by pretreatment CTP, and the final infarct volume (FIV) was measured by diffusion-weighted imaging. A GIC was defined by IICV minus FIV > 10 ml. The CGR was calculated by dividing the IICV by the time from onset to CTP. Univariable analysis and a multivariable logistic regression model were used to evaluate the association between GIC-positive and CGR.

RESULTS

Of all 91 patients, 21 (23.1%) were GIC-positive. The GIC-positive group had higher CGR (14.2 [2.6-46.7] vs 4.8 [1.6-17.1] ml/h, p = 0.02) and complete recanalization (n = 15 (71.4%) vs 29 (41.4%), p = 0.02) compared to the GIC-negative group. On receiver-operating characteristic curve analysis, the optimal cutoff point of CGR to predict GIC-positive was 22 ml/h (sensitivity, 0.48; specificity, 0.85; AUC, 0.67). Multivariable logistic regression analysis showed that CGR ⩾ 22 ml/h (OR 6.44, 95% CI [1.59-26.10], p = 0.01) and complete recanalization (OR 3.72, 95% CI [1.14-12.08], p = 0.02) were independent predictors of GIC-positive.

CONCLUSIONS

A GIC was associated with fast CGR in acute ischemic stroke. Overestimation of the initial ischemic core may be determined by core growth speed.

Clinical and Imaging Features Associated With Fast Infarct Growth During Interhospital Transfers of Patients With Large Vessel Occlusions

BACKGROUND AND OBJECTIVES

Acute ischemic stroke patients with a large vessel occlusion (LVO) who present to a primary stroke center (PSC) often require transfer to a comprehensive stroke center (CSC) for thrombectomy. Not much is known about specific characteristics at the PSC that are associated with infarct growth during transfer. Gaining more insight into these features could aid future trials with cytoprotective agents targeted at slowing infarct growth. We aimed to identify baseline clinical and imaging characteristics that are associated with fast infarct growth rate (IGR) during interhospital transfer.

METHODS

We included patients from the CT Perfusion to Predict Response to Recanalization in Ischemic Stroke Project, a prospective multicenter study. Patients with an anterior circulation LVO who were transferred from a PSC to a CSC for consideration of thrombectomy were eligible if imaging criteria were fulfilled. A CT perfusion (CTP) needed to be obtained at the PSC followed by an MRI at the CSC, before consideration of thrombectomy. The interhospital IGR was defined as the difference between the infarct volumes on MRI and CTP, divided by the time between the scans. Multivariable logistic regression was used to determine characteristics associated with fast IGR (≥5 mL/h).

RESULTS

A total of 183 patients with a median age of 74 years (interquartile range 61-82), of whom 99 (54%) were male and 82 (45%) were fast progressors, were included. At baseline, fast progressors had a higher NIH Stroke Scale score (median 16 vs 13), lower cerebral blood volume index (median 0.80 vs 0.89), more commonly poor collaterals on CT angiography (35% vs 13%), higher hypoperfusion intensity ratios (HIRs) (median 0.51 vs 0.34), and larger core volumes (median 11.80 mL vs 0.00 mL). In multivariable analysis, higher HIR (adjusted odds ratio [aOR] for every 0.10 increase 1.32 [95% CI 1.10-1.59]) and larger core volume (aOR for every 10 mL increase 1.54 [95% CI 1.20-2.11]) remained independently associated with fast IGR.

DISCUSSION

Fast infarct growth during interhospital transfer of acute stroke patients is associated with imaging markers of poor collaterals on baseline imaging. These markers are promising targets for patient selection in cytoprotective trials aimed at reducing interhospital infarct growth.

Exploring ischemic core growth rate and endovascular therapy benefit in large core patients

After stroke onset, ischemic brain tissue will progress to infarction unless blood flow is restored. Core growth rate measures the infarction speed from stroke onset. This multicenter cohort study aimed to explore whether core growth rate influences benefit from the reperfusion treatment of endovascular thrombectomy in large ischemic core stroke patients. It identified 134 patients with large core volume >70 mL assessed on brain perfusion image within 9 hours of stroke onset. Of 134 patients, 71 received endovascular thrombectomy and 63 did not receive the treatment. Overall, poor outcomes were frequent, with 3-month severed disability or death rate at 56% in treatment group and 68% in no treatment group (p = 0.156). Patients were then stratified by core growth rate. For patients with 'ultrafast core growth' of >70 mL/hour, rates of poor outcome were especially high in patients without endovascular thrombectomy (n = 13/14, 93%) and relatively lower in patients received the treatment (n = 12/20, 60%, p = 0.033). In contrast, for patients with core growth rate <70 mL/hour, there was not a large difference in poor outcomes between patients with and without the treatment (55% vs. 61%, p = 0.522). Therefore, patients with 'ultrafast core growth' might stand to benefit the most from endovascular treatment.

Dynamic Evolution of Infarct Volumes at MRI in Ischemic Stroke Due to Large Vessel Occlusion

BACKGROUND AND OBJECTIVES

The typical infarct volume trajectories in stroke patients, categorized as slow or fast progressors, remain largely unknown. This study aimed to reveal the characteristic spatiotemporal evolutions of infarct volumes caused by large vessel occlusion (LVO) and show that such growth charts help anticipate clinical outcomes.

METHODS

We conducted a secondary analysis from prospectively collected databases (FRAME, 2017-2019; ETIS, 2015-2022). We selected acute MRI data from anterior LVO stroke patients with witnessed onset, which were divided into training and independent validation datasets. In the training dataset, using Gaussian mixture analysis, we classified the patients into 3 growth groups based on their rate of infarct growth (diffusion volume/time-to-imaging). Subsequently, we extrapolated pseudo-longitudinal models of infarct growth for each group and generated sequential frequency maps to highlight the spatial distribution of infarct growth. We used these charts to attribute a growth group to the independent patients from the validation dataset. We compared their 3-month modified Rankin scale (mRS) with the predicted values based on a multivariable regression model from the training dataset that used growth group as an independent variable.

RESULTS

We included 804 patients (median age 73.0 years [interquartile range 61.2-82.0 years]; 409 men). The training dataset revealed nonsupervised clustering into 11% (74/703) slow, 62% (437/703) intermediate, and 27% (192/703) fast progressors. Infarct volume evolutions were best fitted with a linear (r = 0.809; p < 0.001), cubic (r = 0.471; p < 0.001), and power (r = 0.63; p < 0.001) function for the slow, intermediate, and fast progressors, respectively. Notably, the deep nuclei and insular cortex were rapidly affected in the intermediate and fast groups with further cortical involvement in the fast group. The variable growth group significantly predicted the 3-month mRS (multivariate odds ratio 0.51; 95% CI 0.37-0.72, p < 0.0001) in the training dataset, yielding a mean area under the receiver operating characteristic curve of 0.78 (95% CI 0.66-0.88) in the independent validation dataset.

DISCUSSION

We revealed spatiotemporal archetype dynamic evolutions following LVO stroke according to 3 growth phenotypes called slow, intermediate, and fast progressors, providing insight into anticipating clinical outcome. We expect this could help in designing neuroprotective trials aiming at modulating infarct growth before EVT.

SWI and CTP fusion model based on sparse representation method to predict cerebral infarction trend

Objective

SWI image signal is related to venous reflux disorder and perfusion defect. Computed tomography perfusion (CTP) contains perfusion information in space and time. There is a complementary basis between them to affect the prognosis of cerebral infarction.

Methods

Sixty-six patients included in the retrospective study were designated as the training set. Effective perfusion indicator features and imaging radiomic features of the peri-infarction area on Susceptibility weighted imaging (SWI) and CTP modality images were extracted from each case. Thirty-three patients from the prospectively included group were designated as the test set of the machine learning model based on a sparse representation method. The predicted results were compared with the DWI results of the patients' 7-10 days review to assess the validity and accuracy of the prediction.

Results

The AUC of the SWI + CTP integrated model was 0.952, the ACC was 0.909, the SEN was 0.889, and the SPE was 0.933. The prediction performance is the highest. Compared with the value of AUC: the SWI model is 0.874, inferior to the performance of the SWI + CTP model, and the CTP model is 0.715.

Conclusion

The prediction efficiency of the changing trend of infarction volume is further improved by the correlation between the combination of the two image features.

Effect of Intravenous Thrombolysis Prior to Mechanical Thrombectomy According to the Location of M1 Occlusion

BACKGROUND AND PURPOSE

The additive effects of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) remain unclear. We aimed to investigate the efficacy and safety of IVT prior to MT depending on the location of M1 occlusion.

METHODS

We reviewed the cases of patients who underwent MT for emergent large-vessel occlusion of the M1 segment. Baseline characteristics as well as clinical and periprocedural variables were compared according to the location of M1 occlusion (i.e., proximal and distal M1 occlusion). The main outcome was the achievement of functional independence (modified Rankin Scale score, 0-2) at 3 months after stroke. The main outcomes were compared between the proximal and distal groups based on the use of IVT before MT.

RESULTS

Among 271 patients (proximal occlusion, 44.6%; distal occlusion, 55.4%), 33.9% (41/121) with proximal occlusion and 24.7% (37/150) with distal occlusion underwent IVT prior to MT. Largeartery atherosclerosis was more common in patients with proximal M1 occlusion; cardioembolism was more common in those with distal M1 occlusion. In patients with proximal M1 occlusion, there was no association between IVT before MT and functional independence. In contrast, there was a significant association between the use of IVT prior to MT (odds ratio=5.30, 95% confidence interval=1.56-18.05, P=0.007) and functional independence in patients with distal M1 occlusion.

CONCLUSION

IVT before MT was associated with improved functional outcomes in patients with M1 occlusion, especially in those with distal M1 occlusion but not in those with proximal M1 occlusion.

Interaction between intravenous thrombolysis and clinical outcome between slow and fast progressors undergoing mechanical thrombectomy: a post-hoc analysis of the SWIFT-DIRECT trial

BACKGROUND

In proximal occlusions, the effect of reperfusion therapies may differ between slow or fast progressors. We investigated the effect of intravenous thrombolysis (IVT) (with alteplase) plus mechanical thrombectomy (MT) versus thrombectomy alone among slow versus fast stroke progressors.

METHODS

The SWIFT-DIRECT trial data were analyzed: 408 patients randomized to IVT+MT or MT alone. Infarct growth speed was defined by the number of points of decay in the initial Alberta Stroke Program Early CT Score (ASPECTS) divided by the onset-to-imaging time. The primary endpoint was 3-month functional independence (modified Rankin scale 0-2). In the primary analysis, the study population was dichotomized into slow and fast progressors using median infarct growth velocity. Secondary analysis was also conducted using quartiles of ASPECTS decay.

RESULTS

We included 376 patients: 191 IVT+MT, 185 MT alone; median age 73 years (IQR 65-81); median initial National Institutes of Health Stroke Scale (NIHSS) 17 (IQR 13-20). The median infarct growth velocity was 1.2 points/hour. Overall, we did not observe a significant interaction between the infarct growth speed and the allocation to either randomization group on the odds of favourable outcome (P=0.68). In the IVT+MT group, odds of any intracranial hemorrhage (ICH) were significantly lower in slow progressors (22.8% vs 36.4%; OR 0.52, 95% CI 0.27 to 0.98) and higher among fast progressors (49.4% vs 26.8%; OR 2.62, 95% CI 1.42 to 4.82) (P value for interaction <0.001). Similar results were observed in secondary analyses.

CONCLUSION

In this SWIFT-DIRECT subanalysis, we did not find evidence for a significant interaction of the velocity of infarct growth on the odds of favourable outcome according to treatment by MT alone or combined IVT+MT. However, prior IVT was associated with significantly reduced occurrence of any ICH among slow progressors whereas this was increased in fast progressors.

Stroke imaging modality for endovascular therapy in the extended window: systematic review and meta-analysis

BACKGROUND

In anterior circulation large vessel occlusion (LVO) in the extended time window, the guidelines recommend advanced imaging (ADVI) to select patients for endovascular therapy (EVT). However, questions remain regarding its availability and applicability in the real world. It is unclear whether an approach to the extended window EVT that does not use ADVI would be equivalent.

METHODS

In April 2022, a literature search was performed to identified randomized controlled trials (RCT) and observational studies describing 90-day outcomes. We performed a meta-analysis of the proportion of aggregate using a random effect to estimate rates of functional independence, defined as modified Rankin Scale (mRS) score ≤2 at 90 days, mean mRS, mortality and symptomatic intracranial hemorrhage (sICH) stratified by imaging modality.

RESULTS

Four RCTs and 28 observational studies were included. The pooled proportion of functional independence among patients selected by ADVI was 44% (95% CI 39% to 48%; I2=80%) and 48% (95% CI 41% to 55%; I2=75%) with non-contrast CT/CT angiography (NCCT/CTA) (p=0.36). Mean mRS with ADVI was 2.88 (95% CI 2.36 to 3.41; I2=0.0%) and 2.79 (95% CI 2.31 to 3.27; I2=0.0%) with NCCT (p=0.79). Mortality in patients selected by ADVI was 13% (95% CI 10% to 17%; I2=81%) and 16% (95% CI 12% to 22%; I2=69%) with NCCT (p=0.29). sICH with ADVI was 4% (95% CI 3% to 7%; I2=73%) and 6% with NCCT/CTA (95% CI 4% to 8%; I2=6%, p=0.27).

CONCLUSIONS

Our study suggests that, in anterior circulation LVO, the rates of functional independence may be similar when patients are selected using ADVI or NCCT for EVT in the extended time window. A simplified triage protocol does not seem to increase mortality or sICH. PROTOCOL REGISTRATION NUMBER: (PROSPERO ID: CRD42021236092).

Bridging Thrombolysis Before Endovascular Therapy in Stroke Patients With Faster Core Growth

BACKGROUND AND OBJECTIVES

It is still uncertain that going direct to endovascular thrombectomy (EVT) leads to equivalent outcomes as bridging IV thrombolysis (IVT) in acute ischemic patients. This study aimed to explore whether the rate of ischemic core growth influenced the patient outcomes after bridging IVT vs direct EVT.

METHODS

This was a retrospective cohort study based on the International Stroke Perfusion Imaging Registry (INSPIRE). It selected acute ischemic stroke patients receiving perfusion CT within 4.5 hours of stroke onset. Patients who went direct to EVT were compared with those who received bridging treatment of IVT before EVT. Ischemic core growth rate was estimated by the acute ischemic core volume on perfusion CT divided by the time from stroke onset to perfusion CT, based on the assumption of a linear growth pattern of ischemic core. Core growth rate was stratified into fast (>15 mL/h) and slow (≤15 mL/h), based on its interaction with bridging IVT in predicting the primary outcome. The primary outcome was modified Rankin scale of 0-2 at 3 months. The secondary outcomes included successful thrombectomy reperfusion defined by modified Thrombolysis in Cerebral Infarction score of 2b-3 and time from groin puncture to reperfusion.

RESULTS

Of the 1,221 EVT patients in the INSPIRE, 323 patients were selected, of which 82 patients received direct EVT and 241 patients received bridging IVT. Bridging IVT was associated with a higher rate of good clinical outcome among patients with fast core growth (39% vs 7% for direct EVT, odds ratio [OR] 8.75 [1.96-39.1], p = 0.005), but the difference was not notable for patients with slow core growth (55% vs 55% for direct EVT, OR 1.00 [0.53-1.87], p = 0.989). In patients with fast core growth, the bridging and direct EVT patients showed no difference in the reperfusion rate (80% vs 76%, p = 0.616). However, patients who received bridging IVT were more likely to achieve reperfusion earlier (the median groin to reperfusion time of 63.0 vs 94.0 minutes, p = 0.005).

DISCUSSION

Patients with fast core growth were more likely to benefit from bridging IVT. This is likely because prior IVT facilitates clot removal and thus reduces time to reperfusion.

Determinants of Infarct Core Growth During Inter-hospital Transfer for Thrombectomy

OBJECTIVE

Patients with acute ischemic stroke harboring a large vessel occlusion who present to primary stroke centers often require inter-hospital transfer for thrombectomy. We aimed to determine clinical and imaging factors independently associated with fast infarct growth (IG) during inter-hospital transfer.

METHODS

We retrospectively analyzed data from acute stroke patients with a large vessel occlusion transferred for thrombectomy from a primary stroke center to one of three French comprehensive stroke centers, with an MRI obtained at both the primary and comprehensive center before thrombectomy. Inter-hospital IG rate was defined as the difference in infarct volumes on diffusion-weighted imaging between the primary and comprehensive center, divided by the delay between the two MRI scans. The primary outcome was identification of fast progressors, defined as IG rate ≥5 mL/hour. The hypoperfusion intensity ratio (HIR), a surrogate marker of collateral blood flow, was automatically measured on perfusion imaging.

RESULTS

A total of 233 patients were included, of whom 27% patients were fast progressors. The percentage of fast progressors was 3% among patients with HIR < 0.40 and 71% among those with HIR ≥ 0.40. In multivariable analysis, fast progression was independently associated with HIR, intracranial carotid artery occlusion, and exclusively deep infarct location at the primary center (C-statistic = 0.95; 95% confidence interval [CI], 0.93-0.98). IG rate was independently associated with good functional outcome (adjusted OR = 0.91; 95% CI, 0.83-0.99; P = 0.037).

INTERPRETATION

Our findings show that a HIR > 0.40 is a powerful indicator of fast inter-hospital IG. These results have implication for neuroprotection trial design, as well as informing triage decisions at primary stroke centers. ANN NEUROL 2023.

Optimizing the Definition of Ischemic Core in CT Perfusion: Influence of Infarct Growth and Tissue-Specific Thresholds

BACKGROUND AND PURPOSE

CTP allows estimating ischemic core in patients with acute stroke. However, these estimations have limited accuracy compared with MR imaging. We studied the effect of applying WM- and GM-specific thresholds and analyzed the infarct growth from baseline imaging to reperfusion.

MATERIALS AND METHODS

This was a single-center cohort of consecutive patients (n = 113) with witnessed strokes due to proximal carotid territory occlusions with baseline CT perfusion, complete reperfusion, and follow-up DWI. We segmented GM and WM, coregistered CTP with DWI, and compared the accuracy of the different predictions for each voxel on DWI through receiver operating characteristic analysis. We assessed the yield of different relative CBF thresholds to predict the final infarct volume and an estimated infarct growth-corrected volume (subtracting the infarct growth from baseline imaging to complete reperfusion) for a single relative CBF threshold and GM- and WM-specific thresholds.

RESULTS

The fixed threshold underestimated lesions in GM and overestimated them in WM. Double GM- and WM-specific thresholds of relative CBF were superior to fixed thresholds in predicting infarcted voxels. The closest estimations of the infarct on DWI were based on a relative CBF of 25% for a single threshold, 35% for GM, and 20% for WM, and they decreased when correcting for infarct growth: 20% for a single threshold, 25% for GM, and 15% for WM. The combination of 25% for GM and 15% for WM yielded the best prediction.

CONCLUSIONS

GM- and WM-specific thresholds result in different estimations of ischemic core in CTP and increase the global accuracy. More restrictive thresholds better estimate the actual extent of the infarcted tissue.

Effectiveness of Thrombectomy in Stroke According to Baseline Prognostic Factors: Inverse Probability of Treatment Weighting Analysis of a Population-Based Registry

Background and Purpose

 In real-world practice, the benefit of mechanical thrombectomy (MT) is uncertain in stroke patients with very favorable or poor prognostic profiles at baseline. We studied the effectiveness of MT versus medical treatment stratifying by different baseline prognostic factors.

Methods

 Retrospective analysis of 2,588 patients with an ischemic stroke due to large vessel occlusion nested in the population-based registry of stroke code activations in Catalonia from January 2017 to June 2019. The effect of MT on good functional outcome (modified Rankin Score ≤2) and survival at 3 months was studied using inverse probability of treatment weighting (IPTW) analysis in three pre-defined baseline prognostic groups: poor (if pre-stroke disability, age >85 years, National Institutes of Health Stroke Scale [NIHSS] >25, time from onset >6 hours, Alberta Stroke Program Early CT Score <6, proximal vertebrobasilar occlusion, supratherapeutic international normalized ratio >3), good (if NIHSS <6 or distal occlusion, in the absence of poor prognostic factors), or reference (not meeting other groups’ criteria).

Results

 Patients receiving MT (n=1,996, 77%) were younger, had less pre-stroke disability, and received systemic thrombolysis less frequently. These differences were balanced after the IPTW stratified by prognosis. MT was associated with good functional outcome in the reference (odds ratio [OR], 2.9; 95% confidence interval [CI], 2.0 to 4.4), and especially in the poor baseline prognostic stratum (OR, 3.9; 95% CI, 2.6 to 5.9), but not in the good prognostic stratum. MT was associated with survival only in the poor prognostic stratum (OR, 2.6; 95% CI, 2.0 to 3.3).

Conclusions

 Despite their worse overall outcomes, the impact of thrombectomy over medical management was more substantial in patients with poorer baseline prognostic factors than patients with good prognostic factors.

Stroke Patients With Faster Core Growth Have Greater Benefit From Endovascular Therapy

BACKGROUND AND PURPOSE

This study aimed to explore whether the therapeutic benefit of endovascular thrombectomy (EVT) was mediated by core growth rate.

METHODS

This retrospective cohort study identified acute ischemic stroke patients with large vessel occlusion and receiving reperfusion treatment, either EVT or intravenous thrombolysis (IVT), within 4.5 hours of stroke onset. Patients were divided into 2 groups: EVT versus IVT only patients (who had no access to EVT). Core growth rate was estimated by the acute core volume on perfusion computed tomography divided by the time from stroke onset to perfusion computed tomography. The primary clinical outcome was good outcome defined by 3-month modified Rankin Scale score of 0-2. Tissue outcome was the final infarction volume.

RESULTS

A total of 806 patients were included, 429 in the EVT group (recanalization rate of 61.6%) and 377 in the IVT only group (recanalization rate of 44.7%). The treatment effect of EVT versus IVT only was mediated by core growth rate, showing a significant interaction between EVT treatment and core growth rate in predicting good clinical outcome (interaction odds ratio=1.03 [1.01-1.05], P=0.007) and final infarct volume (interaction odds ratio=-0.44 [-0.87 to -0.01], P=0.047). For patients with fast core growth of >25 mL/h, EVT treatment (compared with IVT only) increased the odds of good clinical outcome (adjusted odds ratio=3.62 [1.21-10.76], P=0.021) and resulted in smaller final infarction volume (37.5 versus 73.9 mL, P=0.012). For patients with slow core growth of <15 mL/h, there were no significant differences between the EVT and the IVT only group in either good clinical outcome (adjusted odds ratio=1.44 [0.97-2.14], P=0.070) or final infarction volume (22.6 versus 21.9 mL, P=0.551).

CONCLUSIONS

Fast core growth was associated with greater benefit from EVT compared with IVT in the early <4.5-hour time window.

Negative impact of Interhospital Transfer on Clinical Outcomes of Mechanical Thrombectomy for Fast Progressive Stroke

OBJECTIVES

The time-dependence of the clinical outcome of mechanical thrombectomy is higher in the "fast progressor" in whom cerebral ischemia progresses rapidly. The impact of time-consuming interhospital transfer (IT) on the clinical outcome of such patients is unknown. The effect on clinical outcomes of IT of fast progressors was investigated.

METHODS

Among the patients enrolled in the Tokyo/Tama REgistry of Acute endovascular Thrombectomy, fast progressor cerebral ischemia cases were retrospectively investigated. In this study, a fast progressor was defined as a case with an Alberta Stroke Program Early CT Score less than 6 and last known well (LKW) to arterial puncture within 6 h. Patients' background characteristics, treatment progress, and the modified Rankin Scale (mRS) score at 3 months were examined.

RESULTS

Of a total of 1182 patients, 92 (7.8%) were included, with 76 patients in the direct transfer (DT) group, and 16 patients in the IT group. Median LKW to reperfusion was 190 min and 272 min, respectively (P<.001). The number of patients with mRS scores 0-2 at three months was 22 (28.9%) in the DT group and 1 (6.2%) in the IT group. Interhospital transfer was an independent factor associated with worse outcomes (odds ratio 0.08, 95% confidence interval 0.01-0.87, P=.038).

CONCLUSION

This study showed that, among fast progressor patients, the IT group had a worse prognosis than the DT group. To provide good clinical outcomes for fast progressor patients, those who are likely to undergo mechanical thrombectomy should be sent directly to a thrombectomy-capable center.

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.