Endovascular therapy of 623 patients with anterior circulation stroke

Acute ischemic stroke patient factors associated with poor outcomes in patients with favorable collaterals and successful thrombectomy

OBJECTIVES

Favorable arterial collaterals are correlated to favorable outcomes after endovascular thrombectomy (EVT), but many patients still have unfavorable outcomes despite favorable collaterals and successful reperfusion. We determined factors associated with favorable outcome in patients with good collaterals who had successful EVT.

MATERIALS AND METHODS

In a post hoc analysis of the prospective CRISP 2 study, we identified patients with good collaterals (Tan≥2) and successful reperfusion (TICI 2b-3). Favorable (mRS 0-2) and unfavorable outcome (mRS 3-6) groups were compared to identify clinical, imaging, and treatment predictors of favorable outcome.

RESULTS

92 patients were included. 33.7 % had favorable outcomes. There were no differences in sex (52 % females versus 54 % females; p = 0.821) or age (71 years [IQR 56-79] versus 68 years [IQR 57-79]; p = 0.859) in favorable versus unfavorable groups, respectively. Favorable outcome patients had more frequent intravenous thrombolysis (52 % versus 23 %; p = 0.006), shorter EVT procedures (27 min [IQR 23-40] versus 46 min ([IQR 27-64], and lower baseline NIHSS (12 [IQR 9-15] versus 16 [IQR 12-20]; p = 0.006). There were no differences in the frequency of TICI 3 rates (48 % vs. 38 %; p = 0.325) or first pass effect between the two groups (61 % vs. 57 %; p = 0.719). In a multivariable regression analysis, pre-stroke mRS 1 versus 0 versus (OR 0.15 [95 % CI: 0.03-0.78]; p = 0.024), pre-stroke mRS ≥3 versus 0 (OR 0.04 [95 % CI: 0.002-0.94]; p = 0.046), intravenous thrombolysis administration (OR 3.27 [95 % CI: 1.04-10.33]; p = 0.043) and EVT procedure time (OR for every 5 min 0.98 [95 % CI: 0.81-0.98]; p = 0.022) were modifiable predictors of favorable outcomes.

CONCLUSIONS

Among patients with good collaterals and successful reperfusion following EVT, favorable outcomes were associated with lower baseline mRS, intravenous thrombolysis administration, and shorter EVT procedure times.

First clinical multicenter experience of the new NeVa NET 5.5 thrombectomy device

BACKGROUND

Mechanical thrombectomy for the treatment of acute ischemic stroke has undergone relevant technical improvements over recent years. However, distal emboli and incomplete reperfusion after mechanical thrombectomy are still shortcomings in the care of patients with endovascular acute ischemic stroke. The NeVa NET 5.5 thrombectomy device (Vesalio, Nashville, Tennessee, USA) is the first stent retriever featuring an integrated clot micro-filtration system, aiming to enhance first pass efficacy and reduce distal embolization. This study evaluates the safety and efficacy of the NeVa NET 5.5 thrombectomy device.

METHODS

Patients with acute anterior circulation occlusions and vessel diameters >2 mm treated with the NeVa NET 5.5 stent retriever as a first-line approach were retrospectively included in this study. Data were collected from three European comprehensive stroke centers between October 2022 and April 2024. Patient data, occlusion details, clinical outcomes, and procedure-related parameters were analyzed.

RESULTS

A total of 51 patients were included. The most common occlusion locations were the internal carotid artery terminus and intradural internal carotid artery (70.6%). The mean±SD clot length was 25.1±13.3 mm (range 4-50 mm). First pass reperfusion (eTICI 2b-3) was achieved in 78.5%, with a final reperfusion rate of eTICI 2b-3 in 98.1%. Distal embolization in new territories occurred in 3.9%. No device-related adverse events were reported, and procedure-related adverse events occurred in 7.6% of the overall included cases.

CONCLUSION

The NeVa NET 5.5 stent retriever has a high first pass reperfusion rate in large vessel occlusions of the anterior circulation, with a good safety profile and low rate of distal embolization.

Perfusion patterns as a tool for emergency stroke diagnosis: differentiating proximal and distal MCA occlusions

Background

To evaluate the effectiveness of a novel Perfusion Pattern (PP) scale in differentiating between proximal and distal middle cerebral artery (MCA) occlusions in patients with acute ischaemic stroke.

Methods

This retrospective study included 201 patients with acute ischaemic stroke, categorised into two groups: those with M1 segment occlusions (n=114) and those with distal medium vessel occlusions (n=87). We analysed multimodal stroke CT imaging and clinical data, focusing on the occlusion site, hypoperfusion extent and basal ganglia involvement. Patients with tandem stenosis or multiple acute occlusions were excluded. Perfusion patterns were categorised into three types (PP-1, PP-2 and PP-3) based on the extent of hypoperfusion. Statistical analysis explored associations between the occlusion site, perfusion pattern and collateral status.

Results

Among the 201 patients (mean age 75±14 years, 86 men), PP-1 was observed in 36.8% of patients (74/201), PP-2 in 27.4% (55/201) and PP-3 in 35.8% (72/201). The distribution of PP varied significantly by occlusion site (p<0.0001). Distal medium vessel occlusions were associated with PP-1 in 78.4% of cases (58/74), while PP-3 was most prevalent in M1 occlusions (90.3%, 65/72). The contingency coefficient revealed that occlusion location had a stronger association with the perfusion pattern (c=0.556) than collateral type (c=0.245). However, 21.6% of M1 occlusions (16/74) showed a PP-1 pattern and 9.7% of distal medium vessel occlusions (7/72) exhibited PP-3. Basal ganglia infarction presence was a reliable indicator of M1 occlusion with a 94% likelihood.

Conclusions

Perfusion patterns can effectively differentiate between proximal and distal medium vessel MCA occlusions, aiding targeted assessment of CT angiography.

Mef2c Exacerbates Neuron Necroptosis via Modulating Alternative Splicing of Cflar in Ischemic Stroke With Hyperlipidemia

AIM

Hyperlipidemia is a common comorbidity of stroke patients, elucidating the mechanism that underlies the exacerbated ischemic brain injury after stroke with hyperlipidemia is emerging as a significant clinical problem due to the growing proportion of hyperlipidemic stroke patients.

METHODS

Mice were fed a high-fat diet for 12 weeks to induce hyperlipidemia. Transient middle cerebral artery occlusion was induced as a mouse model of ischemic stroke. Emx1Cre mice were crossed with Mef2cfl/fl mice to specifically deplete Mef2c in neurons.

RESULTS

We reported that hyperlipidemia significantly aggravated neuronal necroptosis and exacerbated long-term neurological deficits following ischemic stroke in mice. Mechanistically, Cflar, an upstream necroptotic regulator, was alternatively spliced into pro-necroptotic isoform (CflarR) in ischemic neurons of hyperlipidemic mice. Neuronal Mef2c was a transcription factor modulating Cflar splicing and upregulated by hyperlipidemia following stroke. Neuronal specific Mef2c depletion reduced cerebral level of CflarR and cFLIPR (translated by CflarR), while mitigated neuron necroptosis and neurological deficits following stroke in hyperlipidemic mice.

CONCLUSIONS

Our study highlights the pathogenic role of CflarR splicing mediated by neuronal Mef2c, which aggravates neuron necroptosis following stroke with comorbid hyperlipidemia and proposes CflarR splicing as a potential therapeutic target for hyperlipidemic stroke patients.

Impact of width of susceptibility vessel sign on recanalization following endovascular therapy

BACKGROUND AND PURPOSE

We aimed to investigate the relationship between arterial recanalization following endovascular therapy and the susceptibility vessel sign (SVS) length and width on susceptibility-weighted imaging.

METHODS

We retrospectively evaluated consecutive patients with anterior circulation ischemic stroke who underwent magnetic resonance imaging preceded endovascular therapy, and measured the SVS length and width. Successful recanalization was defined as expanded thrombolysis in cerebral infarction grade of 2b to 3. Logistic regression analysis was executed to determine the independent predictors of successful recanalization and first-pass reperfusion (FPR) after endovascular therapy.

RESULTS

Among 100 patients, successful recanalization and FPR were observed in 77 and 34 patients, respectively. The median SVS length and width were 10.3 mm (interquartile range, 6.8-14.1 mm) and 4.2 mm (interquartile range, 3.1-5.2 mm), respectively. In multivariate logistic regression analysis, SVS width was associated with successful recanalization (odds ratio, 1.88; 95% confidence interval, 1.14-3.07; p = 0.005) and FPR (odds ratio, 1.38; 95% confidence interval, 1.01-1.89; p = 0.039). The optimal cutoff value for the SVS width to predict successful recanalization and FPR were 4.2 mm and 4.0 mm, respectively.

CONCLUSIONS

Larger SVS width may predict successful recanalization and FPR following endovascular therapy.

The impact of leptomeningeal collaterals in acute ischemic stroke: a systematic review and meta-analysis

OBJECTIVES

Leptomeningeal collaterals provide an alternate pathway to maintain cerebral blood flow in stroke to prevent ischemia, but their role in predicting the outcome is still unclear. So, our study aims at assessing the significance of collateral blood flow (CBF) in acute stroke.

METHODS

Electronic databases were searched under different MeSH terms from January 2000 to February 2019. Studies were included if there was available data on good and poor CBF in acute ischemic stroke (AIS). The clinical outcomes included were modified Rankin scale (mRS), recanalization, mortality, and symptomatic intracranial hemorrhage (sICH) at 90 days. Data was analyzed using a random-effect model.

RESULTS

A total of 47 studies with 8194 patients were included. Pooled meta-analysis revealed that there exist twofold higher likelihood of favorable clinical outcome (mRS ≤ 2) at 90 days with good CBF compared with poor CBF (RR: 2.27; 95% CI: 1.94-2.65; p < 0.00001) irrespective of the thrombolytic therapy [RR with IVT: 2.90; 95% CI: 2.14-3.94; p < 0.00001, and RR with IAT/EVT: 1.99; 95% CI: 1.55-2.55; p < 0.00001]. Moreover, there exists onefold higher probability of successful recanalization with good CBF (RR: 1.31; 95% CI: 1.15-1.49; p < 0.00001). However, there was 54% and 64% lower risk of sICH and mortality respectively in patients with good CBF in AIS (p < 0.00001).

CONCLUSIONS

The relative risk of favorable clinical outcome is more in patients with good pretreatment CBF. This could be explained due to better chances of recanalization combined with a lesser risk of intracerebral hemorrhage with good CBF status.

Intravenous tPA (Tissue-Type Plasminogen Activator) Correlates With Favorable Venous Outflow Profiles in Acute Ischemic Stroke

BACKGROUND

Intravenous tPA (tissue-type plasminogen activator) is often administered before endovascular thrombectomy (EVT). Recent studies have questioned whether tPA is necessary given the high rates of arterial recanalization achieved by EVT, but whether tPA impacts venous outflow (VO) is unknown. We investigated whether tPA improves VO profiles on baseline computed tomography (CT) angiography (CTA) images before EVT.

METHODS

Retrospective multicenter cohort study of patients with acute ischemic stroke due to large vessel occlusion undergoing EVT triage. Included patients underwent CT, CTA, and CT perfusion before EVT. VO profiles were determined by opacification of the vein of Labbé, sphenoparietal sinus, and superficial middle cerebral vein on CTA as 0, not visible; 1, moderate opacification; and 2, full. Pial arterial collaterals were graded on CTA, and tissue-level collaterals were assessed on CT perfusion using the hypoperfusion intensity ratio. Clinical and demographic data were determined from the electronic medical record. Using multivariable regression analysis, we determined the correlation between tPA administration and favorable VO profiles.

RESULTS

Seven hundred seventeen patients met inclusion criteria. Three hundred sixty-five patients received tPA (tPA+), while 352 patients were not treated with tPA (tPA-). Fewer tPA+ patients had atrial fibrillation (n=128 [35%] versus n=156 [44%]; P=0.012) and anticoagulants/antiplatelet treatment before acute ischemic stroke due to large vessel occlusion onset (n=130 [36%] versus n=178 [52%]; P<0.001) compared with tPA- patients. One hundred eighty-five patients (51%) in the tPA+ and 100 patients (28%) in the tPA- group exhibited favorable VO (P<0.001). Multivariable regression analysis showed that tPA administration was a strong independent predictor of favorable VO profiles (OR, 2.6 [95% CI, 1.7-4.0]; P<0.001) after control for favorable pial arterial CTA collaterals, favorable tissue-level collaterals on CT perfusion, age, presentation National Institutes of Health Stroke Scale, antiplatelet/anticoagulant treatment, history of atrial fibrillation and time from symptom onset to imaging.

CONCLUSIONS

In patients with acute ischemic stroke due to large vessel occlusion undergoing thrombectomy triage, tPA administration was strongly associated with the presence of favorable VO profiles.

Stroke Core Volume Weighs More Than Recanalization Time for Predicting Outcome in Large Vessel Occlusion Recanalized Within 6 h of Symptoms Onset

Introduction

Current guidelines suggest that perfusion imaging should only be performed > 6 h after symptom onset. Pathophysiologically, brain perfusion should matter whatever the elapsed time. We aimed to compare relative contribution of recanalization time and stroke core volume in predicting functional outcome in patients treated by endovascular thrombectomy within 6-h of stroke-onset.

Methods

Consecutive patients presenting between January 2015 and June 2021 with (i) an acute ischaemic stroke due to an anterior proximal occlusion, (ii) a successful thrombectomy (TICI >2a) within 6-h of symptom-onset and (iii) CT perfusion imaging were included. Core stroke volume was automatically computed using RAPID software. Two linear regression models were built that included in the null hypothesis the pre-treatment NIHSS score and the hypoperfusion volume (Tmax > 6 s) as confounding variables and 24 h post-recanalization NIHSS and 90 days mRS as outcome variables. Time to recanalization was used as covariate in one model and stroke core volume as covariate in the other.

Results

From a total of 377 thrombectomies, 94 matched selection criteria. The Model null hypothesis explained 37% of the variability for 24 h post-recanalization NIHSS and 42% of the variability for 90 days MRS. The core volume as covariate increased outcome variability prediction to 57 and 56%, respectively. Time to recanalization as covariate marginally increased outcome variability prediction from 37 and 34% to 40 and 42.6%, respectively.

Conclusion

Core stroke volume better explains outcome variability in comparison to the time to recanalization in anterior large vessel occlusion stroke with successful thrombectomy done within 6 h of symptoms onset. Still, a large part of outcome variability prediction fails to be explained by the usual predictors.

JET 7 catheter for direct aspiration in carotid T occlusions: preliminary experience and literature review

OBJECTIVE

We report our preliminary experience with the Penumbra JET 7 reperfusion catheter (JET 7), a new large-bore (0.072″) aspiration catheter, in patients with acute ischemic stroke (AIS) due to carotid T occlusion.

METHODS

Data of all eligible patients who received A Direct Aspiration First Pass Technique (ADAPT) for AIS due to carotid T occlusion at our center from March 2018 through June 2020 were retrospectively reviewed. The safety and performance of JET 7 cases and smaller large-bore catheters (LBCs) were compared.

RESULTS

JET 7 was used in 19 patients, and smaller LBCs were used in 41 patients. Median puncture to revascularization time was significantly different between the JET 7 and the smaller LBCs (16 vs. 27 min; P = 0.011). The rate of patients who received rescue therapy with a stent retriever was also significantly different between the JET 7 cases and the smaller LBCs cases (5.3% vs. 22.0%; P = 0.046). Successful revascularization (TICI ≥ 2b) was achieved in 94.7% of JET 7 cases and 75.6% of smaller LBCs cases (P = 0.148). Good functional outcome (mRS 0-2) at 90 days occurred in 63.2% of JET 7 cases and 46.3% of smaller LBCs cases (P = 0.274).

CONCLUSIONS

In this early experience, ADAPT with JET 7 could be considered as one of the possible first-line therapies in carotid T occlusion, showing good rate of vascularization and lower rate of rescue therapy in comparison with smaller LBCs.

Detection of Collaterals from Cone-Beam CT Images in Stroke

Collateral vessels play an important role in the restoration of blood flow to the ischemic tissues of stroke patients, and the quality of collateral flow has major impact on reducing treatment delay and increasing the success rate of reperfusion. Due to high spatial resolution and rapid scan time, advance imaging using the cone-beam computed tomography (CBCT) is gaining more attention over the conventional angiography in acute stroke diagnosis. Detecting collateral vessels from CBCT images is a challenging task due to the presence of noises and artifacts, small-size and non-uniform structure of vessels. This paper presents a technique to objectively identify collateral vessels from non-collateral vessels. In our technique, several filters are used on the CBCT images of stroke patients to remove noises and artifacts, then multiscale top-hat transformation method is implemented on the pre-processed images to further enhance the vessels. Next, we applied three types of feature extraction methods which are gray level co-occurrence matrix (GLCM), moment invariant, and shape to explore which feature is best to classify the collateral vessels. These features are then used by the support vector machine (SVM), random forest, decision tree, and K-nearest neighbors (KNN) classifiers to classify vessels. Finally, the performance of these classifiers is evaluated in terms of accuracy, sensitivity, precision, recall, F-Measure, and area under the receiver operating characteristics curve. Our results show that all classifiers achieve promising classification accuracy above 90% and able to detect the collateral and non-collateral vessels from images.

Course of Early Neurologic Symptom Severity after Endovascular Treatment of Anterior Circulation Large Vessel Occlusion Stroke: Association with Baseline Multiparametric CT Imaging and Clinical Parameters

Background: Neurologic symptom severity and deterioration at 24 hours (h) predict long-term outcomes in patients with acute large vessel occlusion (LVO) stroke of the anterior circulation. We aimed to examine the association of baseline multiparametric CT imaging and clinical factors with the course of neurologic symptom severity in the first 24 h after endovascular treatment (EVT). Methods: Patients with LVO stroke of the anterior circulation were selected from a prospectively acquired consecutive cohort of patients who underwent multiparametric CT, including non-contrast CT, CT angiography and CT perfusion before EVT. The symptom severity was assessed on admission and after 24 h using the 42-point National Institutes of Health Stroke Scale (NIHSS). Clinical and imaging data were compared between patients with and without early neurological deterioration (END). END was defined as an increase in ≥4 points, and a significant clinical improvement as a decrease in ≥4 points, compared to NIHSS on admission. Multivariate regression analyses were used to determine independent associations of imaging and clinical parameters with NIHSS score increase or decrease in the first 24 h. Results: A total of 211 patients were included, of whom 38 (18.0%) had an END. END was significantly associated with occlusion of the internal carotid artery (odds ratio (OR), 4.25; 95% CI, 1.90–9.47) and the carotid T (OR, 6.34; 95% CI, 2.56–15.71), clot burden score (OR, 0.79; 95% CI, 0.68–0.92) and total ischemic volume (OR, 1.01; 95% CI, 1.00–1.01). In a comprehensive multivariate analysis model including periprocedural parameters and complications after EVT, carotid T occlusion remained independently associated with END, next to reperfusion status and intracranial hemorrhage. Favorable reperfusion status and small ischemic core volume were associated with clinical improvement after 24 h. Conclusions: The use of imaging parameters as a surrogate for early NIHSS progression in an acute LVO stroke after EVT reached limited performance with only carotid T occlusion as an independent predictor of END. Reperfusion status and early complications in terms of intracranial hemorrhage are critical factors that influence patient outcome in the acute stroke phase after EVT.

ASPECTS-based selection for late endovascular treatment: a retrospective two-site cohort study

INTRODUCTION

The DAWN trial demonstrated the effectiveness of late endovascular treatment in acute ischemic stroke patients selected on the basis of a clinical-core mismatch. We explored in a real-world sample of endovascular treatment patients if a clinical-ASPECTS (Alberta Stroke Program Early CT Score) mismatch was associated with an outcome benefit after late endovascular treatment.

METHODS

We retrospectively analyzed all consecutive acute ischemic stroke patients admitted 6-24 h after last proof of good health in two stroke centers, with initial National Institutes of Health Stroke Scale (NIHSS) ≥10 and an internal carotid artery or M1 occlusion. We defined clinical-ASPECTS mismatch as NIHSS ≥ 10 and ASPECTS ≥ 7, or NIHSS ≥ 20 and ASPECTS ≥ 5. We assessed the interaction between the presence of the clinical-ASPECTS mismatch and late endovascular treatment using ordinal shift analysis of the three-month modified Rankin Scale and adjusting for multiple confounders.

RESULTS

The included 337 patients had a median age of 73 years (IQR = 61-82), admission NIHSS of 18 (15-22), and baseline ASPECTS of 7 (5-9). Out of 196 (58.2%) patients showing clinical-ASPECTS mismatch, 146 (74.5%) underwent late endovascular treatment. Among 141 (41.8%) mismatch negative patients, late endovascular treatment was performed in 72 (51.1%) patients. In the adjusted analysis, late endovascular treatment was significantly associated with a better outcome in the presence of clinical-ASPECTS mismatch (adjusted odd ratio, aOR = 2.83; 95% confidence interval, CI: 1.48-5.58) but not in its absence (aOR = 1.32; 95%CI: 0.61-2.84). The p-value for the interaction term between clinical-ASPECTS mismatch and late endovascular treatment was 0.073.

CONCLUSIONS

In our retrospective two-site analysis, late endovascular treatment seemed effective in the presence of a clinical-ASPECTS mismatch, but not in its absence. If confirmed in randomized trials, this finding could support the use of an ASPECTS-based selection for late endovascular treatment decisions, obviating the need for advanced imaging.

A novel toolkit for the prediction of clinical outcomes following mechanical thrombectomy

AIM

To develop a robust toolkit to aid decision-making for mechanical thrombectomy (MT) based on readily available patient variables that could accurately predict functional outcome following MT.

MATERIALS AND METHODS

Data from patients with anterior circulation stroke who underwent MT between October 2009 and January 2018 (n=239) were identified from our MT database. Patient explanatory variables were age, sex, National Institutes of Health Stroke Scale (NIHSS), Alberta Stroke Program Early CT Score (ASPECTS), collateral score, and Glasgow Coma Scale. Five models were developed from the data to predict five outcomes of interest: model 1: prediction of survival: modified Rankin Scale (mRS) of 0-5 (alive) or 6 (dead); model 2: prediction of good/poor outcome: mRS of 0-3 (good), or 4-6 (poor); model 3: prediction of good/poor outcome: mRS of 0-2 (good), or 3-6 (poor); model 4: prediction of mRS category: mRS of 0-2 (no disability), 3 (minor disability), 4-5 (severe disability) or 6 (dead); model 5: prediction of the exact mRs score (mRs as a continuous variable). The accuracy and discriminative power of each predictive model were tested.

RESULTS

Prediction of survival was 87% accurate (area under the curve [AUC] 0.89). Prediction of good/poor outcome was 91% accurate (AUC 0.94) for Model 2 and 95% accurate (AUC 0.98) for Model 3. Prediction of mRS category was 76% accurate, and increased to 98% using the "one-score-out rule". Prediction of the exact mRS value was accurate to an error of 0.89.

CONCLUSIONS

This novel toolkit provided accurate estimations of outcome for MT.

Y-Stent Rescue Technique for Failed Thrombectomy in Patients With Large Vessel Occlusion: A Case Series and Pooled Analysis

Objective: Y-stent thrombectomy is a recent rescue technique for failed thrombectomy in patients with emergent large vessel occlusion. We presented case series of using Y-stent rescue technique at different sites and investigate its feasibility and safety through pooled analysis of collected case report or series. Methods: Twenty-eight cases were screened from stroke databank who underwent thrombectomy between January 2015 and June 2019. Clinical, procedural, and follow-up data were investigated and pooled analysis of published literature was analyzed. Results: The occlusion sites include carotid terminus in 14 patients; siphon segment in 3; middle cerebral artery (MCA) in 4; basilar terminus in 7. The overall recanalization rate reached 85.7% (arterial occlusive lesion score 2-3); and final reperfusion rate 85.7% (modified Thrombolysis in Cerebral Infarction 2b-3). After literature review, totally, 52 cases were included. Good clinical outcome was achieved in 26 (50%) and mortality in 7 (17.3%). There is no significant difference on the SAH complication at different sites. Literature review shows no difference between each site in the reperfusion and complication rate. Conclusion: Our case series results suggest that high recanalization rate can be effectively achieved with Y-stent rescue technique for patients with refractory emergent large vessel occlusion. The safety of using this technique at different sites needs further investigation for patients.

Left ventricular systolic dysfunction is associated with poor functional outcomes after endovascular thrombectomy

BACKGROUND

Endovascular thrombectomy (ET) has transformed acute ischemic stroke (AIS) therapy in patients with large vessel occlusion (LVO). Left ventricular systolic dysfunction (LVSD) decreases global cerebral blood flow and predisposes to hypoperfusion. We evaluated the relationship between LVSD, as measured by LV ejection fraction (LVEF), and clinical outcomes in patients with anterior cerebral circulation LVO who underwent ET.

METHODS

This multicenter retrospective cohort study examined anterior circulation LVO AIS patients from six international stroke centers. LVSD was measured by assessment of the echocardiographic LVEF using Simpson's biplane method of discs according to international guidelines. LVSD was defined as LVEF <50%. The primary outcome was defined as a good functional outcome using a modified Rankin Scale (mRS) of 0-2 at 3 months.

RESULTS

We included 440 AIS patients with LVO who underwent ET. On multivariate analyses, pre-existing diabetes mellitus (OR 2.05, 95% CI 1.24 to 3.39;p=0.005), unsuccessful reperfusion (Treatment in Cerebral Infarction (TICI) grade 0-2a) status (OR 4.21, 95% CI 2.04 to 8.66; p<0.001) and LVSD (OR 2.08, 95% CI 1.18 to 3.68; p=0.011) were independent predictors of poor functional outcomes at 3 months. On ordinal (shift) analyses, LVSD was associated with an unfavorable shift in the mRS outcomes (OR 2.32, 95% CI 1.52 to 3.53; p<0.001) after adjusting for age and ischemic heart disease.

CONCLUSION

Anterior circulation LVO AIS patients with LVSD have poorer outcomes after ET, suggesting the need to consider cardiac factors for ET, the degree of monitoring and prognostication post-procedure.

How Long Are Reperfusion Therapies Beneficial for Patients after Stroke Onset? Lessons from Lethal Ischemia Following Early Reperfusion in a Mouse Model of Stroke

Ischemic stroke caused by cerebral artery occlusion induces neurological deficits because of cell damage or death in the central nervous system. Given the recent therapeutic advances in reperfusion therapies, some patients can now recover from an ischemic stroke with no sequelae. Currently, reperfusion therapies focus on rescuing neural lineage cells that survive in spite of decreases in cerebral blood flow. However, vascular lineage cells are known to be more resistant to ischemia/hypoxia than neural lineage cells. This indicates that ischemic areas of the brain experience neural cell death but without vascular cell death. Emerging evidence suggests that if a vascular cell-mediated healing system is present within ischemic areas following reperfusion, the therapeutic time window can be extended for patients with stroke. In this review, we present our comments on this subject based upon recent findings from lethal ischemia following reperfusion in a mouse model of stroke.

The Hyperdense Middle Cerebral Artery Sign in Drip-and-Ship Models of Acute Stroke Management

Background

Large vessel occlusion (LVO) leads to debilitating stroke and responds modestly to recombinant tissue plasminogen activator (rt-TPA). Early thrombectomy improves functional outcomes in selected patients with proximal occlusion but it is not available in all medical facilities. The best imaging modality for triage in an acute stroke setting in drip-and-ship models is still the subject of debate.

Objectives

We aimed to assess the diagnostic value of millimeter-sliced noncontrast computed tomography (NCCT) hyperdense middle cerebral artery sign (HMCAS) in itself or associated with clinical data for early detection of LVO in drip-and-ship models of acute stroke management.

Methods

NCCT of patients admitted to the Erasme Hospital, ULB, Brussels, Belgium, for suspicion of acute ischemic stroke between January 1 and July 31, 2017, were collected. Patients with brain hemorrhages were excluded, leading to 122 cases. The presence of HMCAS on NCCT was determined via visual assessment by 6 raters blinded to all other data. An independent rater assessed the presence of LVO on digital subtraction angiography imaging or contrast-enhanced CT angiography (CTA). The sensitivity, false-positive rate (FPR), and accuracy of HMCAS and the dot sign to detect LVO were calculated. The interobserver agreement of HMCAS was assessed using Gwet's AC1 coefficient. Then, on a separate occasion, the first 2 observers rereviewed all NCCT provided with clinical clues. The sensitivity, FPR, and accuracy of HMCAS were recalculated.

Results

HMCAS was found in 21% of the cases and a dot sign was found in 9%. The mean HMCAS sensitivity was 62% (95% CI 45–79%) and its accuracy was 86% (95% CI 79–92%) for detecting LVO. The interobserver reliability coefficient was 80% for HMCAS. Combined with clinical information, HMCAS sensitivity increased to 81% (95% CI 68–94; p = 0.041) and accuracy increased to 91% (95% CI 86–96%).

Conclusion

When clinical data are provided, detection of HMCAS on thinly sliced NCCT could be enough to decide on transfer for thrombectomy in drip-and-ship models of acute stroke management, especially in situations where CTA is less available and referral centers for thrombectomy fewer and further apart.

EphA4/Tie2 crosstalk regulates leptomeningeal collateral remodeling following ischemic stroke

Leptomeningeal anastomoses or pial collateral vessels play a critical role in cerebral blood flow (CBF) restoration following ischemic stroke. The magnitude of this adaptive response is postulated to be controlled by the endothelium, although the underlying molecular mechanisms remain under investigation. Here we demonstrated that endothelial genetic deletion, using EphA4fl/fl/Tie2-Cre and EphA4fl/fl/VeCahderin-CreERT2 mice and vessel painting strategies, implicated EphA4 receptor tyrosine kinase as a major suppressor of pial collateral remodeling, CBF, and functional recovery following permanent middle cerebral artery occlusion. Pial collateral remodeling is limited by the crosstalk between EphA4-Tie2 signaling in vascular endothelial cells, which is mediated through p-Akt regulation. Furthermore, peptide inhibition of EphA4 resulted in acceleration of the pial arteriogenic response. Our findings demonstrate that EphA4 is a negative regulator of Tie2 receptor signaling, which limits pial collateral arteriogenesis following cerebrovascular occlusion. Therapeutic targeting of EphA4 and/or Tie2 represents an attractive new strategy for improving collateral function, neural tissue health, and functional recovery following ischemic stroke.

Selection of Candidates for Endovascular Treatment: Characteristics According to Three Different Selection Methods

Background and Purpose

To investigate the number and characteristics of patients eligible for endovascular treatment (EVT) determined using three different selection methods: clinical-core mismatch, target mismatch, and collateral status.

Methods

Using the data of consecutive patients from two prospectively maintained registries of university medical centers, the number and characteristics of patients according to the three selection methods were investigated and their correlation was analyzed. Patients with anterior circulation stroke due to occlusion of the middle cerebral and/or internal carotid artery and a National Institute of Health Stroke Scale (NIHSS) score of ≥6 points, who arrived within 8 hours or between 6 and 12 hours of symptom onset and underwent magnetic resonance imaging prior to EVT, were included. Collateral status was assessed using magnetic resonance perfusion-derived collateral flow maps.

Results

Three hundred thirty-five patients were investigated; the proportions of patients who were eligible and ineligible for EVT in all three selection methods were both small (n=85, 25.4%; n=54, 16.1%, respectively). The intercorrelation among the three selection methods was low (κ=0.235). The baseline NIHSS score and onset-to-selection time interval were associated with the presence of clinical-core mismatch, while the penumbra/core volume ratio and onset-to-selection time interval were related to target mismatch; none of these variables were associated with collateral status. The infarct core volume was associated with favorable profiles in all three selection methods.

Conclusions

Although the application of individual selection methods resulted in favorable outcomes after EVT in clinical trials, there is a significant discrepancy in EVT eligibility depending on the selection method used.

Factors Associated with Unsuccessful Recanalization in Mechanical Thrombectomy for Acute Ischemic Stroke

Introduction

Mechanical thrombectomy (MT) for acute ischemic stroke has become a standard therapy, and the recanalization rate has significantly improved. However, some cases of unsuccessful recanalization still occur. We aimed to clarify patient factors associated with unsuccessful recanalization after MT for acute ischemic stroke.

Methods

This was a single-center, retrospective study of 119 consecutive patients with anterior circulation acute ischemic stroke who underwent MT at our hospital between April 2015 and March 2019. Successful recanalization after MT was defined as modified Treatment in Cerebral Ischemia (mTICI) grade 2b or 3, and unsuccessful recanalization was defined as mTICI grades 0–2a. Several factors were analyzed to assess their effect on recanalization rates.

Results

Successful recanalization was achieved in 88 patients (73.9%). The univariate analysis showed that female sex (38.6 vs. 67.7%, p = 0.007), a history of hypertension (53.4 vs. 83.9%, p = 0.003), and a longer time from groin puncture to recanalization (median 75 vs. 124 min, p < 0.001) were significantly associated with unsuccessful recanalization. The multivariate analysis confirmed that female sex (OR 3.18; 95% CI 1.12–9.02, p = 0.030), a history of hypertension (OR 4.84; 95% CI 1.32–17.8, p = 0.018), M2–3 occlusion (OR 4.26; 95% CI 1.36–13.3, p = 0.013), and the time from groin puncture to recanalization (per 10-min increase, OR 1.22; 95% CI 1.09–1.37, p < 0.001) were independently associated with unsuccessful recanalization.

Conclusion

Female sex and a history of hypertension might be predictors of unsuccessful recanalization after MT for anterior circulation acute ischemic stroke. Further studies are needed to fully evaluate predictors of recanalization.

Endovascular treatment for acute carotid T and carotid non-T occlusion: A retrospective multicentre study of 81 patients

BACKGROUND

The functional prognosis of patients with carotid T occlusion is poor, but few comprehensive studies have investigated carotid non-T occlusion, in which the terminal internal carotid artery portion is unobstructed. We aimed to elucidate the clinical features of carotid non-T occlusion by comparing patients with acute carotid T occlusion and carotid non-T occlusion.

METHODS

Among 362 patients who underwent thrombectomy between January 2015 and June 2018, 20 and 61 were diagnosed with carotid non-T occlusion and carotid T occlusion, respectively. We compared preoperative clinical findings, treatment strategies, treatment complications and functional outcomes between the two groups.

RESULTS

Age, sex, preoperative National Institutes of Health stroke scale, cerebral infarction subtypes and medical history did not significantly differ. In contrast, preoperative diffusion-weighted imaging-Alberta Stroke Program early computed tomography scores were 9 (1-11) and 6.5 (0-11) for the carotid non-T occlusion and carotid T occlusion groups, respectively (P = 0.015). The duration of treatment or the median number of passes (2.5 vs. 2.0), the numbers of patients with thrombolysis in cerebral infarction 2b/3, bleeding complications and modified Rankin scale scores of 0-2 on postoperative day 90 did not significantly differ between the two groups. Manual aspiration before, internal carotid artery arrest while crossing a lesion and injection into the contralateral side were significantly more frequent in patients with carotid non-T occlusion. Intracranial internal carotid artery stenosis was significantly more frequent in patients with carotid non-T occlusion (n = 4, 20%) than carotid T occlusion (n = 0), and 10% of patients with carotid non-T occlusion had arterial dissection.

CONCLUSION

Patients with carotid non-T occlusion more frequently had a background of intracranial internal carotid artery stenosis or arterial dissection than patients with carotid T occlusion. Specific treatment strategies should be developed to improve the clinical outcomes of patients with carotid non-T occlusion.

Cerebral Collateral Circulation: A Review in the Context of Ischemic Stroke and Mechanical Thrombectomy

The pial (leptomenigeal) collateral circulation is a key determinant of functional outcome after mechanical thrombectomy after large-vessel ischemic stroke. Patients with good collateral blood flow benefit up to 24 hours after stroke onset, whereas those with poor collateral flow evidence less or no benefit. However, clues to why collateral flow varies so widely among patients have remained elusive. Recent findings in animal studies, which are currently being tested for confirmation in humans, have found that naturally occurring variants of a novel "collateral gene," Rabep2, result in large differences in the extent of anatomic collaterals and thus blood flow and infarct size in mice after stroke. The comprehension of collagerogenesis in humans and the evaluation of collateral status could aid in identifying patients who will benefit not only from mechanical thrombectomy in the extended time window but also from any reperfusion strategy. We performed a literature review focused on radiographic, clinical, and genetic aspects of the collateral circulation.

Relating Acute Lesion Loads to Chronic Outcome in Ischemic Stroke-An Exploratory Comparison of Mismatch Patterns and Predictive Modeling

Objectives: To investigate the relationship between imaging features derived from lesion loads and 3 month clinical assessments in ischemic stroke patients. To support clinically implementable predictive modeling with information from lesion-load features. Methods: A retrospective cohort of ischemic stroke patients was studied. The dataset was dichotomized based on revascularization treatment outcome (TICI score). Three lesion delineations were derived from magnetic resonance imaging in each group: two clinically implementable (threshold based and fully automatic prediction) and 90-day follow-up as final groundtruth. Lesion load imaging features were created through overlay of the lesion delineations on a histological brain atlas, and were correlated with the clinical assessment (NIHSS). Significance of the correlations was assessed by constructing confidence intervals using bootstrap sampling. Results: Overall, high correlations between lesion loads and clinical score were observed (up to 0.859). Delineations derived from acute imaging yielded on average somewhat lower correlations than delineations derived from 90-day follow-up imaging. Correlations suggest that both total lesion volume and corticospinal tract lesion load are associated with functional outcome, and in addition highlight other potential areas associated with poor clinical outcome, including the primary somatosensory cortex BA3a. Fully automatic prediction was comparable to ADC threshold-based delineation on the successfully treated cohort and superior to the Tmax threshold-based delineation in the unsuccessfully treated cohort. Conclusions: The confirmation of established predictors for stroke outcome (e.g., corticospinal tract integrity and total lesion volume) gives support to the proposed methodology-relating acute lesion loads to 3 month outcome assessments by way of correlation. Furthermore, the preliminary results indicate an association of further brain regions and structures with three month NIHSS outcome assessments. Hence, prediction models might observe an increased accuracy when incorporating regional (instead of global) lesion loads. Also, the results lend support to the clinical utilization of the automatically predicted volumes from FASTER, rather than the simpler DWI and PWI lesion delineations.

Multimodal MRI-Based Triage for Acute Stroke Therapy: Challenges and Progress

Revascularization therapies have been established as the treatment mainstay for acute ischemic stroke. However, a substantial number of patients are either ineligible for revascularization therapy, or the treatment fails or is futile. At present, non-contrast computed tomography is the first-line neuroimaging modality for patients with acute stroke. The use of magnetic resonance imaging (MRI) to predict the response to early revascularization therapy and to identify patients for delayed treatment is desirable. MRI could provide information on stroke pathophysiologies, including the ischemic core, perfusion, collaterals, clot, and blood–brain barrier status. During the past 20 years, there have been significant advances in neuroimaging as well as in revascularization strategies for treating patients with acute ischemic stroke. In this review, we discuss the role of MRI and post-processing, including machine-learning techniques, and recent advances in MRI-based triage for revascularization therapies in acute ischemic stroke.

Impact of smoking on stroke outcome after endovascular treatment

Background

Recent studies suggest a paradoxical association between smoking status and clinical outcome after intravenous thrombolysis (IVT). Little is known about relationship between smoking and stroke outcome after endovascular treatment (EVT).

Methods

We analyzed data of all stroke patients treated with EVT at the tertiary stroke centre of Berne between January 2005 and December 2015. Using uni- and multivariate modeling, we assessed whether smoking was independently associated with excellent clinical outcome (modified Rankin Scale (mRS) 0–1) and mortality at 3 months. In addition, we also measured the occurrence of symptomatic intracranial hemorrhage (sICH) and recanalization.

Results

Of 935 patients, 204 (21.8%) were smokers. They were younger (60.5 vs. 70.1 years of age, p<0.001), more often male (60.8% vs. 52.5%, p = 0.036), had less often from hypertension (56.4% vs. 69.6%, p<0.001) and were less often treated with antithrombotics (35.3% vs. 47.7%, p = 0.004) as compared to nonsmokers. In univariate analyses, smokers had higher rates of excellent clinical outcome (39.1% vs. 23.1%, p<0.001) and arterial recanalization (85.6% vs. 79.4%, p = 0.048), whereas mortality was lower (15.6% vs. 25%, p = 0.006) and frequency of sICH similar (4.4% vs. 4.1%, p = 0.86). After correcting for confounders, smoking still independently predicted excellent clinical outcome (OR 1.758, 95% CI 1.206–2.562; p<0.001).

Conclusion

Smoking in stroke patients may be a predictor of excellent clinical outcome after EVT. However, these data must not be misinterpreted as beneficial effect of smoking due to the observational study design. In view of deleterious effects of cigarette smoking on cardiovascular health, cessation of smoking should still be strongly recommended for stroke prevention.

Refocusing Neuroprotection in Cerebral Reperfusion Era: New Challenges and Strategies

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

Increased blood pressure variability after endovascular thrombectomy for acute stroke is associated with worse clinical outcome

BACKGROUND AND PURPOSE

Blood pressure variability has been found to contribute to worse outcomes after intravenous tissue plasminogen activator, but the association has not been established after intra-arterial therapies.

METHODS

We retrospectively reviewed patients with an ischemic stroke treated with intra-arterial therapies from 2005 to 2015. Blood pressure variability was measured as standard deviation (SD), coefficient of variation (CV), and successive variation (SV). Ordinal logistic regression models were fitted to the outcome of the modified Rankin Scale (mRS) with univariable predictors of systolic blood pressure variability. Multivariable ordinal logistic regression models were fitted to the outcome of mRS with covariates that showed independent predictive ability (P<0.1).

RESULTS

There were 182 patients of mean age 63.2 years and 51.7% were female. The median admission National Institutes of Health Stroke Scalescore was 16 and 47.3% were treated with intravenous tissue plasminogen activator. In a univariable ordinal logistic regression analysis, systolic SD, CV, and SV were all significantly associated with a 1-point increase in the follow-up mRS (OR 2.30-4.38, all P<0.002). After adjusting for potential confounders, systolic SV was the best predictor of a 1-point increase in mRS at follow-up (OR 2.63-3.23, all P<0.007).

CONCLUSIONS

Increased blood pressure variability as measured by the SD, CV, and SV consistently predict worse neurologic outcomes as measured by follow-up mRS in patients with ischemic stroke treated with intra-arterial therapies. The SV is the strongest and most consistent predictor of worse outcomes at all time intervals.

Spatially extended versus frontal cerebral near-infrared spectroscopy during cardiac surgery: a case series identifying potential advantages

Stroke due to hypoperfusion or emboli is a devastating adverse event of cardiac surgery, but early detection and treatment could protect patients from an unfavorable postoperative course. Hypoperfusion and emboli can be detected with transcranial Doppler of the middle cerebral artery (MCA). The measured blood flow velocity correlates with cerebral oxygenation determined clinically by near-infrared spectroscopy (NIRS) of the frontal cortex. We tested the potential advantage of a spatially extended NIRS in detecting critical events in three cardiac surgery patients with a whole-head fiber holder of the FOIRE-3000 continuous-wave NIRS system. Principle components analysis was performed to differentiate between global and localized hypoperfusion or ischemic territories of the middle and anterior cerebral arteries. In one patient, we detected a critical hypoperfusion of the right MCA, which was not apparent in the frontal channels but was accompanied by intra- and postoperative neurological correlates of ischemia. We conclude that spatially extended NIRS of temporal and parietal vascular territories could improve the detection of critically low cerebral perfusion. Even in severe hemispheric stroke, NIRS of the frontal lobe may remain normal because the anterior cerebral artery can be supplied by the contralateral side directly or via the anterior communicating artery.

MR Perfusion to Determine the Status of Collaterals in Patients with Acute Ischemic Stroke: A Look Beyond Time Maps

BACKGROUND AND PURPOSE

Patients with acute stroke with robust collateral flow have better clinical outcomes and may benefit from endovascular treatment throughout an extended time window. Using a multiparametric approach, we aimed to identify MR perfusion parameters that can represent the extent of collaterals, approximating DSA.

MATERIALS AND METHODS

Patients with anterior circulation proximal arterial occlusion who had baseline MR perfusion and DSA were evaluated. The volume of arterial tissue delay (ATD) at thresholds of 2-6 seconds (ATD^{2-6 seconds}) and >6 seconds (ATD^{>6 seconds}) in addition to corresponding values of normalized CBV and CBF was calculated using VOI analysis. The association of MR perfusion parameters and the status of collaterals on DSA were assessed by multivariate analyses. Receiver operating characteristic analysis was performed.

RESULTS

Of 108 patients reviewed, 39 met our inclusion criteria. On DSA, 22/39 (56%) patients had good collaterals. Patients with good collaterals had significantly smaller baseline and final infarct volumes, smaller volumes of severe hypoperfusion (ATD^{>6 seconds}), larger volumes of moderate hypoperfusion (ATD^{2-6 seconds}), and higher relative CBF and relative CBV values than patients with insufficient collaterals. Combining the 2 parameters into a Perfusion Collateral Index (volume of ATD^{2-6 seconds} × relative CBV^{2-6 seconds}) yielded the highest accuracy for predicting collateral status: At a threshold of 61.7, this index identified 15/17 (88%) patients with insufficient collaterals and 22/22 (100%) patients with good collaterals, for an overall accuracy of 94.1%.

CONCLUSIONS

The Perfusion Collateral Index can predict the baseline collateral status with 94% diagnostic accuracy compared with DSA.

ASTRAL-R score predicts non-recanalisation after intravenous thrombolysis in acute ischaemic stroke

Intravenous thrombolysis (IVT) as treatment in acute ischaemic strokes may be insufficient to achieve recanalisation in certain patients. Predicting probability of non-recanalisation after IVT may have the potential to influence patient selection to more aggressive management strategies. We aimed at deriving and internally validating a predictive score for post-thrombolytic non-recanalisation, using clinical and radiological variables. In thrombolysis registries from four Swiss academic stroke centres (Lausanne, Bern, Basel and Geneva), patients were selected with large arterial occlusion on acute imaging and with repeated arterial assessment at 24 hours. Based on a logistic regression analysis, an integer-based score for each covariate of the fitted multivariate model was generated. Performance of integerbased predictive model was assessed by bootstrapping available data and cross validation (delete-d method). In 599 thrombolysed strokes, five variables were identified as independent predictors of absence of recanalisation: Acute glucose > 7 mmol/l (A), significant extracranial vessel STenosis (ST), decreased Range of visual fields (R), large Arterial occlusion (A) and decreased Level of consciousness (L). All variables were weighted 1, except for (L) which obtained 2 points based on β-coefficients on the logistic scale. ASTRAL-R scores 0, 3 and 6 corresponded to non-recanalisation probabilities of 18, 44 and 74 % respectively. Predictive ability showed AUC of 0.66 (95 %CI, 0.61–0.70) when using bootstrap and 0.66 (0.63–0.68) when using delete-d cross validation. In conclusion, the 5-item ASTRAL-R score moderately predicts non-recanalisation at 24 hours in thrombolysed ischaemic strokes. If its performance can be confirmed by external validation and its clinical usefulness can be proven, the score may influence patient selection for more aggressive revascularisation strategies in routine clinical practice.

Iatrogenic Vessel Dissection in Endovascular Treatment of Acute Ischemic Stroke

Purpose

Knowledge about the localization and outcome of iatrogenic dissection (ID) during endovascular treatment of acute ischemic stroke (AIS) is limited. We aimed to determine the frequency, clinical aspects and morphology of ID in endovascular AIS treatment and to identify predictors of this complication.

Methods

Digital subtraction angiography (DSA) of ID carried out during endovascular treatment between January 2000 and March 2012 have been re-evaluated. The ID localization and morphology were analyzed and related to the interventional techniques. Baseline clinical and radiological findings, treatment modality and outcome were compared with patients without ID.

Results

Out of 866 patients 18 (2%) suffered an ID (44% female, median age 64 years). Localization was extracranial in 15 (83%, 14 internal carotid artery and 1 vertebral artery) and intracranial in 3 (17%; 1 vertebrobasilar dissection and 2 in the anterior circulation). Of the IDs 5 (28%) resulted in a high-degree, 3 (17%) in a moderate, 5 (28%) in a mild and 5 (28%) in no stenosis and 8 IDs were stented in the acute phase. At 3 months 7 (42%) patients had a favorable outcome (modified Rankin score mRS ≤ 2) and 6 (33%) patients had died. Patients with ID had a different stroke etiology (p = 0.041), were more likely to be smokers (44% versus 19%, p = 0.015) and were more likely to be treated with mechanical thrombectomy (100% versus 60%, p < 0.001). Although two ID patients had relevant complications, the outcome did not differ between the groups.

Conclusion

The occurrence of ID is a rare complication of endovascular AIS treatment associated with smoking and mechanical thrombectomy.

Electronic supplementary material

The online version of this article (10.1007/s00062-017-0639-z) contains supplementary material, which is available to authorized users.

Fully automated stroke tissue estimation using random forest classifiers (FASTER)

Several clinical trials have recently proven the efficacy of mechanical thrombectomy for treating ischemic stroke, within a six-hour window for therapy. To move beyond treatment windows and toward personalized risk assessment, it is essential to accurately identify the extent of tissue-at-risk ("penumbra"). We introduce a fully automated method to estimate the penumbra volume using multimodal MRI (diffusion-weighted imaging, a T2w- and T1w contrast-enhanced sequence, and dynamic susceptibility contrast perfusion MRI). The method estimates tissue-at-risk by predicting tissue damage in the case of both persistent occlusion and of complete recanalization. When applied to 19 test cases with a thrombolysis in cerebral infarction grading of 1-2a, mean overestimation of final lesion volume was 30 ml, compared with 121 ml for manually corrected thresholding. Predicted tissue-at-risk volume was positively correlated with final lesion volume ( p < 0.05). We conclude that prediction of tissue damage in the event of either persistent occlusion or immediate and complete recanalization, from spatial features derived from MRI, provides a substantial improvement beyond predefined thresholds. It may serve as an alternative method for identifying tissue-at-risk that may aid in treatment selection in ischemic stroke.

Is ultrasound perfusion imaging capable of detecting mismatch? A proof-of-concept study in acute stroke patients

In this study, we compared contrast-enhanced ultrasound perfusion imaging with magnetic resonance perfusion-weighted imaging or perfusion computed tomography for detecting normo-, hypo-, and nonperfused brain areas in acute middle cerebral artery stroke. We performed high mechanical index contrast-enhanced ultrasound perfusion imaging in 30 patients. Time-to-peak intensity of 10 ischemic regions of interests was compared to four standardized nonischemic regions of interests of the same patient. A time-to-peak >3 s (ultrasound perfusion imaging) or >4 s (perfusion computed tomography and magnetic resonance perfusion) defined hypoperfusion. In 16 patients, 98 of 160 ultrasound perfusion imaging regions of interests of the ischemic hemisphere were classified as normal, and 52 as hypoperfused or nonperfused. Ten regions of interests were excluded due to artifacts. There was a significant correlation of the ultrasound perfusion imaging and magnetic resonance perfusion or perfusion computed tomography (Pearson's chi-squared test 79.119, p < 0.001) (OR 0.1065, 95% CI 0.06-0.18). No perfusion in ultrasound perfusion imaging (18 regions of interests) correlated highly with diffusion restriction on magnetic resonance imaging (Pearson's chi-squared test 42.307, p < 0.001). Analysis of receiver operating characteristics proved a high sensitivity of ultrasound perfusion imaging in the diagnosis of hypoperfused area under the curve, (AUC = 0.917; p < 0.001) and nonperfused (AUC = 0.830; p < 0.001) tissue in comparison with perfusion computed tomography and magnetic resonance perfusion. We present a proof of concept in determining normo-, hypo-, and nonperfused tissue in acute stroke by advanced contrast-enhanced ultrasound perfusion imaging.

The effects of pharmaceutical thrombolysis and multi-modal therapy on patients with acute posterior circulation ischemic stroke: Results of a one center retrospective study

BACKGROUND

The treatment method for acute ischemic stroke is rapidly developing, and the effects of endovascular modalities, when used alone or in combination, needs to be studied. We aimed to identify the difference between pharmaceutical thrombolysis and multi-modal therapy (MMT) used in acute posterior circulation ischemic stroke (APCIS) patients and also to detect the predictors for successful recanalization and favorable outcomes.

METHODS

A retrospective analysis of patients with APCIS who received thrombolytic pharmaceuticals and MMT from 2011 to 2016 was performed at the stroke center. Demographic information, therapeutic methods and the results were recorded. Logistic regression model was constructed in variables to determine the predictors of outcome.

RESULTS

A total of 124 patients were included in this study, the mean age was 59.6 ± 9.5 years and the mean admission National Institutes of Health Stroke Scale (NIHSS) was 15.1 ± 6.6. Recanalization was achieved in 87 (70.2%) patients and favorable outcomes were observed in 65 (52.4%) patients. Patients treated with MMT demonstrated a higher recanalization rate, especially the use of stent placement and thrombectomy device, which were also related to the favorable outcome three months post-stroke. Logistic regression showed that stent placement and thrombectomy were the predictors of recanalization, and a favorable outcome was associated with coronary artery disease, MMT methods as well as recanalization.

CONCLUSION

MMT methods, especially stent placement and thrombectomy device may be the first recommended for patients with a delayed admission time, and it may have the advantage of better perfusion and neurological outcomes.

Impact of Slow Blood Filling via Collaterals on Infarct Growth: Comparison of Mismatch and Collateral Status

Background and Purpose

Perfusion-diffusion mismatch has been evaluated to determine whether the presence of a target mismatch helps to identify patients who respond favorably to recanalization therapies. We compared the impact on infarct growth of collateral status and the presence of a penumbra, using magnetic resonance perfusion (MRP) techniques.

Methods

Consecutive patients who were candidates for recanalization therapy and underwent serial diffusion-weighted imaging (DWI) and MRP were enrolled. A collateral flow map derived from MRP source data was generated by automatic post-processing. The impact of a target mismatch (Tmax>6 s/apparent diffusion coefficient (ADC) volume≥1.8, ADC volume<70 mL; and Tmax>10 s for ADC volume<100 mL) on infarct growth was compared with MR-based collateral grading on day 7 DWI, using multivariate linear regression analysis.

Results

Among 73 patients, 55 (75%) showed a target mismatch, whereas collaterals were poor in 14 (19.2%), intermediate in 36 (49.3%), and good in 23 (31.5%) patients. After adjusting for initial severity of stroke, early recanalization (P<0.001) and the MR-based collateral grading (P=0.001), but not the presence of a target mismatch, were independently associated with infarct growth. Even in patients with a target mismatch and successful recanalization, the degree of infarct growth depended on the collateral status. Perfusion status at later Tmax time points (beyond the arterial phase) was more closely correlated with collateral status.

Conclusions

Patients with good collaterals show a favorable outcome in terms of infarct growth, regardless of the presence of a target mismatch pattern. The presence of slow blood filling predicts collateral status and infarct growth.

Endovascular Therapy of M2 Occlusion in IMS III: Role of M2 Segment Definition and Location on Clinical and Revascularization Outcomes

BACKGROUND AND PURPOSE

Uncertainty persists regarding the safety and efficacy of endovascular therapy of M2 occlusions following IV tPA. We reviewed the impact of revascularization on clinical outcomes in 83 patients with M2 occlusions in the Interventional Management of Stroke III trial according to specific M1-M2 segment anatomic features.

MATERIALS AND METHODS

Perfusion of any M2 branch distinguished M2-versus-M1 occlusion. Prespecified modified TICI and arterial occlusive lesion revascularization and clinical mRS 0-2 end points at 90 days for endovascular therapy-treated M2 occlusions were analyzed. Post hoc analyses of the relationship of outcomes to multiple baseline angiographic M2 and M1 subgroup characteristics were performed.

RESULTS

Of 83 participants with M2 occlusion who underwent endovascular therapy, 41.0% achieved mRS 0-2 at 90 days, including 46.6% with modified TICI 2-3 reperfusion compared with 26.1% with modified TICI 0-1 reperfusion (risk difference, 20.6%; 95% CI, -1.4%-42.5%). mRS 0-2 outcome was associated with reperfusion for M2 trunk (n = 9) or M2 division (n = 42) occlusions, but not for M2 branch occlusions (n = 28). Of participants with trunk and division occlusions, 63.2% with modified TICI 2a and 42.9% with modified TICI 2b reperfusion achieved mRS 0-2 outcomes; mRS 0-2 outcomes for M2 trunk occlusions (33%) did not differ from distal (38.2%) and proximal (26.9%) M1 occlusions.

CONCLUSIONS

mRS 0-2 at 90 days was dependent on reperfusion for M2 trunk but not for M2 branch occlusions. For M2 division occlusions, good outcome with modified TICI 2b reperfusion did not differ from that in modified TICI 2a. M2 segment definition and occlusion location may contribute to differences in revascularization and good outcome between Interventional Management of Stroke III and other endovascular therapy studies.

Collateral state and the effect of endovascular reperfusion therapy on clinical outcome in ischemic stroke patients

PURPOSE

Clinically successful endovascular therapy (EVT) in ischemic stroke requires reliable noninvasive pretherapeutic selection criteria. We investigated the association of imaging parameters including CT angiographic collaterals and degree of reperfusion with clinical outcome after EVT.

METHODS

In our database, we identified 93 patients with large vessel occlusion in the anterior circulation treated with EVT. Besides clinical data, we assessed the baseline Alberta Stroke Program Early CT score (ASPECTS) on noncontrast CT (NCCT) and CT angiography (CTA) source images, collaterals (CT-CS) and clot burden score (CBS) on CTA and the degree of reperfusion after EVT on angiography. Three readers, blinded to clinical information, evaluated the images in consensus. Data-driven multivariable ordinal regression analysis identified predictors of good outcome after 90 days as measured with the modified Rankin Scale.

RESULTS

Successful angiographic reperfusion (OR 26.50; 95%-CI 9.33-83.61) and good collaterals (OR 9.69; 95%-CI 2.28-59.27) were independent predictors of favorable outcome along with female sex (OR 0.35; 95%-CI 0.14-0.85), younger age (OR 0.88; 95%-CI 0.83-0.92) and higher NCCT ASPECTS (OR 2.54; 95%-CI 1.01-6.63). Outcome was best in patients with good collaterals and successful reperfusion, but there was no statistical interaction between collaterals and reperfusion.

CONCLUSIONS

CTA-collateral status was the strongest pretherapeutic predictor of favorable outcome in ischemic stroke patients treated with EVT. CTA-collaterals are thus well suited for patient selection in EVT. However, the independent effect of reperfusion on outcome tended to be stronger than that of CTA-collaterals.

Impact of collaterals on the efficacy and safety of endovascular treatment in acute ischaemic stroke: a systematic review and meta-analysis

OBJECTIVE

We aimed to investigate the role of pretreatment collateral status in predicting the efficacy and safety of endovascular treatment (EVT) in acute ischaemic stroke due to cervical and/or cerebral arterial occlusions.

METHODS

Relevant full-text articles published since 1 January 2000, investigating correlations between collateral status and any efficacy or safety outcome in patients undergoing EVT in cohort or case-control studies, or randomised clinical trials, were retrieved by PubMed and manual search. Two authors extracted data from eligible studies and assessed study quality. Risk ratios (RR) were pooled for good versus poor collaterals for outcomes based on a random-effects model. Sensitivity and subgroup analyses were conducted.

RESULTS

In total, 35 (3542 participants) and 23 (2652 participants) studies were included in qualitative review and quantitative meta-analysis, respectively. Overall, good pretreatment collaterals increased the rate of favourable functional outcome at 3 months (RR=1.98, 95% CI 1.64 to 2.38; p<0.001), and reduced the risks of periprocedural symptomatic intracranial haemorrhage (RR=0.59, 95% CI 0.43 to 0.81; p=0.001) and 3-month mortality (RR=0.49, 95% CI 0.38 to 0.63; p<0.001), as compared with poor collaterals, in patients with acute ischaemic stroke under EVT. No individual study could alter the estimate of overall effect of collateral status, but there were moderate to significant heterogeneities between subgroups of studies with different modes of EVT, different arterial occlusions and different collateral grading methods.

CONCLUSIONS

Good pretreatment collateral status is associated with higher rates of favourable functional outcome, and lower rates of symptomatic intracranial haemorrhage and mortality, in patients with acute ischaemic stroke receiving endovascular therapies.

Enrollment bias: frequency and impact on patient selection in endovascular stroke trials

BACKGROUND

Selection bias may have affected enrollment in first generation endovascular stroke trials. We investigate, evaluate, and quantify such bias for these trials at our institution.

METHODS

Demographic, clinical, imaging, and angiographic data were prospectively collected on a consecutive cohort of patients with acute ischemic stroke who were enrolled in formal trials of endovascular stroke therapy (EST) or received EST in clinical practice outside of a randomized trial for acute cerebral ischemia at a single tertiary referral center from September 2004 to December 2012.

RESULTS

Among patients considered appropriate for EST in practice, 47% were eligible for trials, with rates for individual trials ranging from 17% to 70%. Compared with trial ineligible patients treated with EST, trial eligible patients were younger (67 vs. 74 years; p<0.05), more often treated with intravenous tissue plasminogen activator (53% vs. 34%; p<0.01), and had shorter last known well to puncture times (328 vs. 367 min; p<0.05). Focusing on the largest trial with a non-interventional control arm, compared with trial eligible patients treated with EST outside the trial, enrolled patients presented later (274 vs. 163 min; p<0.001), had higher National Institutes of Health Stroke Scale scores (20 vs. 17; p<0.05), and larger strokes (diffusion weighted imaging volumes 49 vs. 18; p<0.001).

CONCLUSIONS

The majority of patients felt suitable for EST at our institution were excluded from recent trials. Formal entry criteria succeeded in selecting patients with better prognostic features, although many of these patients were treated outside of trials. Acknowledging and mitigating these biases will be crucial to ongoing investigations.

Logistical and financial obstacles for endovascular therapy of acute stroke implementation

After publication of the recent positive randomized clinical endovascular trials, several questions and obstacles for wide spread implementation remain. We address specific issues namely efficacy, safety, logistics, timing, sedation, numbers, imaging, manpower, centers, geographics, and economical aspects of endovascular therapy. As we move forward, a high degree of collaboration will be crucial to implement a therapy with established overwhelming treatment efficacy for severe acute stroke patients.

Lenticulostriate infarctions after successful mechanical thrombectomy in middle cerebral artery occlusion

BACKGROUND

In stroke due to middle cerebral artery (MCA) occlusion, collaterals may sustain tissue in the peripheral MCA territory, extending the time window for recanalizing therapies. However, MCA occlusions often block some or all of the 'lenticulostriate' (LS) arteries originating from the M1 segment, eliminating blood flow to dependent territories in the striatum, which have no collateral supply. This study examines whether mechanical thrombectomy (MTE) can avert imminent striatal infarction in patients with acute MCA occlusion.

METHODS

279 patients with isolated MCA occlusion subjected to MTE were included. Actual LS occlusions and infarctions were assigned to predefined 'LS occlusion' and 'LS infarct' patterns derived from known LS vascular anatomy. The predictive performance of LS occlusion patterns regarding ensuing infarction in striatal subterritories was assessed by standard statistical measures.

RESULTS

LS occlusion patterns predicted infarction in associated striatal subterritories with a positive predictive value (PPV) of 91% and a negative predictive value of 81%. In 15 of the 22 patients who did not develop the predicted striatal infarctions, reassessment of angiographies revealed LS vascular supply variants that explained these 'false positive' LS occlusion patterns, raising the PPV to 96%. Symptom onset to recanalization times were relatively short, but this alone could not account for the false positive LS occlusion patterns in the remaining seven of these patients.

CONCLUSIONS

With currently achievable symptom onset to recanalization times, striatal infarctions are determined by MCA occlusion sites and individual vascular anatomy, and cannot normally be averted by MTE, but there are exceptions. Further study of such exceptional cases may yield important insights into the determinants of infarct growth in the hyperacute phase of infarct evolution.

Effect of endovascular reperfusion in relation to site of arterial occlusion

OBJECTIVE

To assess whether the association between reperfusion and improved clinical outcomes after stroke differs depending on the site of the arterial occlusive lesion (AOL).

METHODS

We pooled data from Solitaire With the Intention for Thrombectomy (SWIFT), Solitaire FR Thrombectomy for Acute Revascularisation (STAR), Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2 (DEFUSE 2), and Interventional Management of Stroke Trial (IMS III) to compare the strength of the associations between reperfusion and clinical outcomes in patients with internal carotid artery (ICA), proximal middle cerebral artery (MCA) (M1), and distal MCA (M2/3/4) occlusions.

RESULTS

Among 710 included patients, the site of the AOL was the ICA in 161, the proximal MCA in 389, and the distal MCA in 160 patients (M2 = 131, M3 = 23, and M4 = 6). Reperfusion was associated with an increase in the rate of good functional outcome (modified Rankin Scale [mRS] score 0-2) in patients with ICA (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.7-7.2) and proximal MCA occlusions (OR 6.2, 95% CI 3.8-10.2), but not in patients with distal MCA occlusions (OR 1.4, 95% CI 0.8-2.6). Among patients with M2 occlusions, a subset of the distal MCA cohort, reperfusion was associated with excellent functional outcome (mRS 0-1; OR 2.2, 95% CI 1.0-4.7).

CONCLUSIONS

The association between endovascular reperfusion and better clinical outcomes is more profound in patients with ICA and proximal MCA occlusions compared to patients with distal MCA occlusions. Because there are limited data from randomized controlled trials on the effect of endovascular therapy in patients with distal MCA occlusions, these results underscore the need for inclusion of this subgroup in future endovascular therapy trials.

Occlusion Location of Middle Cerebral Artery Stroke and Outcome after Endovascular Treatment

BACKGROUND

The aim of this study was to analyze the influence of the location of middle cerebral artery (MCA) occlusion on recanalization, complications and outcome after endovascular therapy.

METHODS

Four-hundred sixty-four patients with acute MCA occlusions were treated with endovascular therapy.

RESULTS

Two-hundred ninety-three patients had M1 occlusions, 116 had M2, and 55 had M3/4 occlusions. Partial or complete recanalization was more frequently achieved in M1 (76.8%) than in M2 (59.1%) or M3/4 (47.3%, p < 0.001) occlusions, but favorable outcome (modified Rankin Scale 0-2) was less frequent in M1 (50.9%) than M2 (63.7%) or M3/4 (72.7%, p = 0.018) occlusions. Symptomatic intracerebral hemorrhage (ICH) did not differ between occlusion sites, but asymptomatic ICH was more common in M1 (22.6%) than in M2 occlusions (8.6%, p = 0.003). Recanalization was associated with favorable outcome in M1 (p < 0.001) and proximal M2 (p = 0.003) but not in distal M2 or M3/4 occlusions.

CONCLUSIONS

Recanalization with endovascular therapy was more frequently achieved in patients with proximal than distal MCA occlusions, but recanalization was associated with favorable outcome only in M1 and proximal M2 occlusions. Outcome was better with distal than proximal occlusions. This study shows that recanalization can be used as a surrogate marker for clinical outcome only in patients with proximal occlusions.