Clinical benefit of thrombectomy in stroke patients with low ASPECTS is mediated by oedema reduction

Impact of first pass effect in endovascular treatment of large core stroke: a post-hoc analysis of the ANGEL-ASPECT trial

BACKGROUND

The first-pass effect (FPE) is linked to better safety and efficacy prognosis in patients with small- to- moderate sized ischemic infarctions. We evaluated the incidence, prognosis, and predictors of FPE in patients with large core infarctions (LCIs).

METHODS

We conducted a post-hoc analysis of data from the Trial of Endovascular Therapy in Acute Anterior Circulation Large Vessel Occlusive Patients with a Large Infarct Core (ANGEL-ASPECT). The FPE was defined as a successful recanalization (expanded Thrombolysis in Cerebral Infarction (eTICI) 2 c/3, and eTICI 2b-3 as modified FPE (mFPE)) after one pass. The primary outcome was clinical functional independence, and the secondary outcomes were independent ambulation, assessed by the modified Rankin Scale (mRS) at 90 days. Safety outcomes included symptomatic intracranial hemorrhage (sICH) defined by the Heidelberg bleeding classification, any intracranial hemorrhage (ICH), and death within 90 days of stroke onset.

RESULTS

Of the 226 patients in the study, FPE and mFPE were achieved in 33 (14.6%) and 82 (36.3%) patients, respectively. Patients with FPE exhibited shorter onset-to-puncture times (adjusted odds ratio [OR] 0.915; 95% confidence interval [CI]: 0.84 to 0.996), and patients with mFPE were older (OR 1.039; 95% CI: 1.005 to 1.075). mFPE was significantly associated with favorable outcomes (modified Rankin score [mRS] 0-2: OR 2.64; 95% CI: 1.37 to 5.07; mRS 0-3: OR 3.31; 95% CI: 1.73 to 6.33). FPE tended to improve outcomes (mRS 0-3: OR 2.24; 95% CI: 0.92 to 4.97; p=0.08). ICH rates (OR 0.60; 95% CI: 0.34 to 1.05; p=0.07) and 90-day deaths (OR 0.57; 95% CI: 0.30 to 1.09; p=0.09) tended to decrease in patients who achieved mFPE but not in patients who achieved FPE.

CONCLUSIONS

In the ANGEL-ASPECT trial, patients who achieved mFPE had a higher rate of independent ambulation and functional independence, and the rates of any ICH and 90-day death tended to decrease.

Endovascular thrombectomy with or without intravenous alteplase in large-core ischemic stroke: a systematic review and meta-analysis

The role of bridging intravenous thrombolysis (IVT) with alteplase before endovascular thrombectomy (EVT) in treating large core ischemic stroke remains uncertain. We aimed to compare clinical outcomes and safety of EVT with or without bridging IVT in patients with anterior circulation large vessel occlusion (ACLVO) and baseline Alberta Stroke Program Early CT Score (ASPECTS) ≤ 5. We systematically searched PubMed, Web of Science, Cochrane Library, and Embase from inception until November 2023. The primary outcome was 90-day functional independence (modified Rankin Scale [mRS] 0-2). Secondary outcomes included 90-day independent ambulation (mRS 0-3), successful recanalization, any intracranial hemorrhage (ICH), symptomatic ICH (sICH) and 90-day mortality. A random-effects model was used for data pooling. Five high-quality studies, incorporating 2124 patients (41% treated with bridging IVT), were included. Across both unadjusted and adjusted analyses, no significant differences were found between the bridging IVT and EVT-alone groups in terms of functional independence (odds ratios [OR] = 1.36, 95% confidence interval [CI]: 0.90-2.07, P = 0.14; adjusted OR [aOR] = 1.19, 95% CI: 0.68-2.09, P = 0.53) or independent ambulation (OR = 1.14, 95% CI: 0.80-1.62, P = 0.47; aOR = 1.18, 95% CI: 1.00-1.39, P = 0.05) at 90 days. Furthermore, no differences were observed in successful recanalization, any ICH, sICH, and 90-day mortality between the two treatment groups. Bridging IVT exhibits similar functional and safety outcomes compared to EVT alone in ACLVO patients with baseline ASPECTS ≤ 5. Further research is warranted to confirm these findings.

Safety and clinical outcomes of endovascular therapy versus medical management in late presentation of large ischemic stroke

INTRODUCTION

The benefit of endovascular therapy (EVT) among stroke patients with large ischemic core (ASPECTS 0-5) in the extended time window outside of trial settings remains unclear. We analyzed the effect of EVT among these stroke patients in real-world settings.

PATIENTS AND METHODS

The CT for Late Endovascular Reperfusion (CLEAR) study recruited patients from 66 centers in 10 countries between 01/2014 and 05/2022. The extended time-window was defined as 6-24 h from last-seen-well to treatment. The primary outcome was shift of the 3-month modified Rankin scale (mRS) score. Safety outcomes included symptomatic intracranial hemorrhage (sICH) and mortality. Outcomes were analyzed with ordinal and logistic regressions.

RESULTS

Among 5098 screened patients, 2451 were included in the analysis (median age 73, 55% women). Of patients with ASPECTS 0-5 (n = 310), receiving EVT (n = 209/310) was associated with lower 3-month mRS when compared to medical management (median 4 IQR 3-6 vs 6 IQR 4-6; aOR 0.4, 95% CI 0.2-0.7). Patients undergoing EVT had higher sICH (11.2% vs 4.0%; aOR 4.1, 95% CI 1.2-18.8) and lower mortality (31.6% vs 58.4%, aOR 0.4; 95% CI 0.2-0.9) compared to medically managed patients. The relative benefit of EVT was comparable between patients with ASPECTS 0 and 5 and 6-10 in the extended time window (interaction aOR 0.9; 95% CI 0.5-1.7).

CONCLUSION

In the extended time window, patients with ASPECTS 0-5 may have preserved relative treatment benefit of EVT compared to patients with ASPECTS 6-10. These findings are in line with recent trials showing benefit of EVT among real-world patients with large ischemic core in the extended time window.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov; Unique identifier: NCT04096248.

Thrombectomy in Patients With Ischemic Stroke Without Salvageable Tissue on CT Perfusion

BACKGROUND

Computed tomography perfusion (CTP) imaging is regularly used to guide patient selection for mechanical thrombectomy (MT). However, the effect of MT in patients without salvageable tissue on CTP has not been investigated. The purpose of this study was to assess the effect of MT in patients with stroke without perfusion mismatch profiles.

METHODS

This observational study analyzed patients with ischemic stroke consecutively treated between March 1, 2015, and January 31, 2022, triaged by multimodal-computed tomography undergoing MT. CTP lesion-core mismatch profiles were defined using a mismatch volume/ratio of ≥10 mL/1.2, respectively. The primary end point was the rate of functional independence at 90 days, defined as the modified Rankin Scale score of 0 to 2. Recanalization was evaluated with the modified Thrombolysis in Cerebral Infarction scale. The effect of baseline variables on functional outcome was assessed using multivariable logistic regression analysis. Outcomes of patients with and without CTP-mismatch profiles were compared using 1:1 propensity score matching.

RESULTS

Of 724 patients who met the inclusion criteria of this retrospective observational study, 110 (15%) patients had no CTP mismatch and were analyzed. The median age was 74 (interquartile range, 62-80) years and 53% were women. Successful recanalization (modified Thrombolysis in Cerebral Infarction score, ≥2b) was achieved in 66% (73) and associated with functional independence at 90 days (adjusted odds ratio, 7.33 [95% CI, 1.22-43.70]; P=0.03). A significant interaction was observed between recanalization and age, as well as the extent of infarction, indicating MT to be most effective in patients <70 years and with a baseline Alberta Stroke Program Early Computed Tomography Score range between 3 and 7. These findings remained stable after propensity score matching, analyzing 152 matched pairs with similar rates of functional independence between patients with and without CTP-mismatch profiles (17% versus 23%; P=0.42).

CONCLUSIONS

In patients without CTP-mismatch profiles defined according to the EXTEND (Extending the Time for Thrombolysis in Emergency Neurological Deficits) criteria, recanalization was associated with improved functional outcomes. This effect was associated with baseline Alberta Stroke Program Early Computed Tomography Score and age, but not with the time from onset to imaging.

Endovascular Thrombectomy for Large Ischemic Strokes with ASPECTS 0-2: a Meta-analysis of Randomized Controlled Trials

PURPOSE

Randomized controlled trials (RCTs) demonstrated a treatment effect of endovascular thrombectomy in acute ischemic stroke with large infarct, commonly defined as an Alberta Stroke Program Early CT Score (ASPECTS) of 3-5. However, data on endovascular thrombectomy in patients with very low ASPECTS of 0-2 remain scarce.

METHODS

We conducted a systematic review and meta-analysis of RCTs comparing endovascular thrombectomy versus medical treatment alone in acute ischemic anterior circulation stroke with very large infarct, defined as ASPECTS of 0-2. The primary outcome was the shift toward better functional outcomes on the 90-day modified Rankin Scale (mRS). Random effects meta-analysis was performed using the generic inverse variance method.

RESULTS

Literature research identified four RCTs which evaluated the treatment effect of endovascular thrombectomy for large infarcts and provided a subgroup analysis of the mRS shift in patients with ASPECTS of 0-2. The pooled analysis showed a significant shift toward better 90-day mRS scores in favor of endovascular thrombectomy (pooled odds ratio, 1.62, 95% confidence interval, 1.29-2.04, P < 0.001).

CONCLUSION

This meta-analysis suggests a treatment effect of endovascular thrombectomy in specific patients with very low ASPECTS of 0-2, challenging the use of ASPECTS for treatment selection in acute ischemic stroke due to large vessel occlusion. An individual patient meta-analysis of RCTs would strengthen evidence in the treatment of patients with ASPECTS of 0-2.

The feasibility of mechanical thrombectomy versus medical management for acute stroke with a large ischemic territory

BACKGROUND

Mechanical thrombectomy (MT) for acute ischemic stroke is generally avoided when the expected infarction is large (defined as an Alberta Stroke Program Early CT Score of <6).

OBJECTIVE

To perform a meta-analysis of recent trials comparing MT with best medical management (BMM) for treatment of acute ischemic stroke with large infarction territory, and then to determine the cost-effectiveness associated with those treatments.

METHODS

A meta-analysis of the RESCUE-Japan, SELECT2, and ANGEL-ASPECT trials was conducted using R Studio. Statistical analysis employed the weighted average normal method for calculating mean differences from medians in continuous variables and the risk ratio for categorical variables. TreeAge software was used to construct a cost-effectiveness analysis model comparing MT with BMM in the treatment of ischemic stroke with large infarction territory.

RESULTS

The meta-analysis showed significantly better functional outcomes, with higher rates of patients achieving a modified Rankin Scale score of 0-3 at 90 days with MT as compared with BMM. In the base-case analysis using a lifetime horizon, MT led to a greater gain in quality-adjusted life-years (QALYs) of 3.46 at a lower cost of US$339 202 in comparison with BMM, which led to the gain of 2.41 QALYs at a cost of US$361 896. The incremental cost-effectiveness ratio was US$-21 660, indicating that MT was the dominant treatment at a willingness-to-pay of US$70 000.

CONCLUSIONS

This study shows that, besides having a better functional outcome at 90-days' follow-up, MT was more cost-effective than BMM, when accounting for healthcare cost associated with treatment outcome.

Effect of Postoperative Prolonged sedation with Dexmedetomidine after successful reperfusion with Endovascular Thrombectomy on long-term prognosis in patients with acute ischemic stroke (PPDET): study protocol for a randomized controlled trial

BACKGROUND

Endovascular thrombectomy (EVT) is a standard treatment for acute ischemic stroke (AIS) with large vessel occlusion. Hypertension and increased blood pressure variability within the first 24 h after successful reperfusion are related to a higher risk of symptomatic intracerebral hemorrhage and higher mortality. AIS patients might suffer from ischemia-reperfusion injury following reperfusion, especially within 24 h. Dexmedetomidine (DEX), a sedative commonly used in EVT, can stabilize hemodynamics by inhibiting the sympathetic nervous system and alleviate ischemia-reperfusion injury through anti-inflammatory and antioxidative properties. Postoperative prolonged sedation for 24 h with DEX might be a potential pharmacological approach to improve long-term prognosis after EVT.

METHODS

This single-center, open-label, prospective, randomized controlled trial will include 368 patients. The ethics committee has approved the protocol. After successful reperfusion (modified thrombolysis in cerebral infarction scores 2b-3, indicating reperfusion of at least 50% of the affected vascular territory), participants are randomly assigned to the intervention or control group. In the intervention group, participants will receive 0.1~1.0 μg/kg/h DEX for 24 h. In the control group, participants will receive an equal dose of saline for 24 h. The primary outcome is the functional outcome at 90 days, measured with the categorical scale of the modified Rankin Scale, ranging from 0 (no symptoms) to 6 (death). The secondary outcome includes (1) the changes in stroke severity between admission and 24 h and 7 days after EVT, measured by the National Institute of Health Stroke Scale (ranging from 0 to 42, with higher scores indicating greater severity); (2) the changes in ischemic penumbra volume/infarct volume between admission and 7 days after EVT, measured by neuroimaging scan; (3) the length of ICU/hospital stay; and (4) adverse events and the all-cause mortality rate at 90 days.

DISCUSSION

This randomized clinical trial is expected to verify the hypothesis that postoperative prolonged sedation with DEX after successful reperfusion may promote the long-term prognosis of patients with AIS and may reduce the related socio-economic burden.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04916197. Prospectively registered on 7 June 2021.

Quantification of ischemic brain edema after mechanical thrombectomy using dual-energy computed tomography in patients with ischemic stroke

Net water uptake (NWU) is a quantitative imaging biomarker used to assess cerebral edema resulting from ischemia via Computed Tomography (CT)-densitometry. It serves as a strong predictor of clinical outcome. Nevertheless, NWU measurements on follow-up CT scans after mechanical thrombectomy (MT) can be affected by contrast staining. To improve the accuracy of edema estimation, virtual non-contrast images (VNC-I) from dual-energy CT scans (DECT) were compared to conventional polychromatic CT images (CP-I) in this study. We examined NWU measurements derived from VNC-I and CP-I to assess their agreement and predictive value in clinical outcome. 88 consecutive patients who received DECT as follow-up after MT were included. NWU was quantified on CP-I (cNWU) and VNC-I (vNWU). The clinical endpoint was functional independence at discharge. cNWU and vNWU were highly correlated (r = 0.71, p < 0.0001). The median difference between cNWU and vNWU was 8.7% (IQR: 4.5-14.1%), associated with successful vessel recanalization (mTICI2b-3) (ß: 11.6%, 95% CI 2.9-23.0%, p = 0.04), and age (ß: 4.2%, 95% CI 1.3-7.0%, p = 0.005). The diagnostic accuracy to classify outcome between cNWU and vNWU was similar (AUC:0.78 versus 0.77). Although there was an 8.7% median difference, indicating potential edema underestimation on CP-I, it did not have short-term clinical implications.

Novel advanced imaging techniques for cerebral oedema

Cerebral oedema following acute ischemic infarction has been correlated with poor functional outcomes and is the driving mechanism of malignant infarction. Measurements of midline shift and qualitative assessment for herniation are currently the main CT indicators for cerebral oedema but have limited sensitivity for small cortical infarcts and are typically a delayed sign. In contrast, diffusion-weighted (DWI) or T2-weighted magnetic resonance imaging (MRI) are highly sensitive but are significantly less accessible. Due to the need for early quantification of cerebral oedema, several novel imaging biomarkers have been proposed. Based on neuroanatomical shift secondary to space-occupying oedema, measures such as relative hemispheric volume and cerebrospinal fluid displacement are correlated with poor outcomes. In contrast, other imaging biometrics, such as net water uptake, T2 relaxometry and blood brain barrier permeability, reflect intrinsic tissue changes from the influx of fluid into the ischemic region. This review aims to discuss quantification of cerebral oedema using current and developing advanced imaging techniques, and their role in predicting clinical outcomes.

Penumbra salvage in extensive stroke: exploring limits for reperfusion therapy

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of endovascular therapy in large anterior circulation ischaemic strokes: A systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

The benefit of endovascular treatment in large anterior circulation ischaemic strokes with low ASPECTS score (<6) is uncertain. Recent randomised studies have demonstrated the benefit of endovascular treatment (EVT) in large ischaemic strokes. The present meta-analysis aims to assess the combined effect of these studies on efficacy and safety of endovascular treatment in this group of patients.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Databases MEDLINE, PubMed, EMBASE, SCOPUS, Google Scholar, Tripdatabase were searched for randomised controlled trials with at least 50 participants from inception until February 16, 2023. The primary efficacy outcome analysed was the relative risk of functional independence defined as mRS - 0-2 at 90 days. Secondary efficacy outcomes included early neurological improvement, death due to any cause at 90 days and proportion of patients requiring decompressive hemicraniectomy. The primary safety outcome was the risk of developing symptomatic intracerebral haemorrhage (sICH).

RESULTS

A total of three studies (RESCUE Japan-LIMIT, SELECT 2 and ANGEL ASPECTS) involving 1011 patients; 510 in the EVT arm and 501 in the medical management (MM) arm met the defined criteria (ASPECTS-3-5). The combined RR for the primary outcome of mRS 0-2 was 2.53 [1.84-3.47] (p = <0.0001) favouring EVT over MM. The primary safety outcome of sICH was not significant in the EVT arm with a combined RR of 1.84 [0.94-3.60] (p = 0.5157). Mortality rates were similar in both arms (26.67% in EVT arm vs 27.94% in MM arm) with a combined RR of 0.95 [0.78; 1.16] (p = 1.000).

CONCLUSION

In patients with Large vessel occlusion (LVO) and low ASPECTS (3-5), EVT was associated with higher likelihood of achieving functional independence and early neurologic improvement but did not provide any mortality benefit.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Occult contrast retention post-thrombectomy on 24-h follow-up dual-energy CT: Associations and impact on imaging analysis

BACKGROUND

Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU).

AIMS

We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema.

METHODS

Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS).

RESULTS

Of 125 patients analyzed (median age 71 (IQR = 61-80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75-21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b-3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = -0.035, p = 0.35; MLS rho = 0.035, p = 0.347).

CONCLUSIONS

Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.

Brain edema growth after thrombectomy is associated with comprehensive collateral blood flow

BACKGROUND

We determined whether a comprehensive assessment of cerebral collateral blood flow is associated with ischemic lesion edema growth in patients successfully treated by thrombectomy.

METHODS

This was a multicenter retrospective study of ischemic stroke patients who underwent thrombectomy treatment of large vessel occlusions. Collateral status was determined using the cerebral collateral cascade (CCC) model, which comprises three components: arterial collaterals (Tan Scale) and venous outflow profiles (Cortical Vein Opacification Score) on CT angiography, and tissue-level collaterals (hypoperfusion intensity ratio) on CT perfusion. Quantitative ischemic lesion net water uptake (NWU) was used to determine edema growth between admission and follow-up non-contrast head CT (ΔNWU). Three groups were defined: CCC+ (good pial collaterals, tissue-level collaterals, and venous outflow), CCC- (poor pial collaterals, tissue-level collaterals, and venous outflow), and CCCmixed (remainder of patients). Primary outcome was ischemic lesion edema growth (ΔNWU). Multivariable regression models were used to assess the primary and secondary outcomes.

RESULTS

538 patients were included. 157 patients had CCC+, 274 patients CCCmixed, and 107 patients CCC- profiles. Multivariable regression analysis showed that compared with patients with CCC+ profiles, CCC- (β 1.99, 95% CI 0.68 to 3.30, P=0.003) and CCC mixed (β 1.65, 95% CI 0.75 to 2.56, P<0.001) profiles were associated with greater ischemic lesion edema growth (ΔNWU) after successful thrombectomy treatment. ΔNWU (OR 0.74, 95% CI 0.68 to 0.8, P<0.001) and CCC+ (OR 13.39, 95% CI 4.88 to 36.76, P<0.001) were independently associated with functional independence.

CONCLUSION

A comprehensive assessment of cerebral collaterals using the CCC model is strongly associated with edema growth and functional independence in acute stroke patients successfully treated by endovascular thrombectomy.

The ACORNS grading scale: a novel tool for the prediction of malignant brain edema after endovascular thrombectomy

BACKGROUND

To develop and validate a novel tool for predicting the development of malignant brain edema (MBE) in large vessel occlusion stroke patients after endovascular thrombectomy (EVT).

METHODS

We used a prospectively registered population of EVT patients from three comprehensive stroke centers. The population was randomly divided into two subsets (7:3): a training cohort and an internal validation cohort. External validation was performed using the Endovascular Treatment for Acute Anterior Circulation Ischemic Stroke Registry in China (ACTUAL) database. MBE was defined as (1) hypodense parenchyma in at least 50% of the middle cerebral artery and signs of local brain swelling, and (2) a midline shift of ≥5 mm at the septum pellucidum or pineal gland with obliteration of the basal cisterns. The model was constructed using logistic regression analysis. The performance of the model was examined in terms of discrimination and calibration.

RESULTS

After adjusting for other confounders, baseline National Institutes of Health Stroke Scale (NIHSS) and Alberta Stroke Program Early CT (ASPECT) scores, a clinical history of hypertension, collateral status, intravenous thrombolysis before thrombectomy, fasting blood glucose, reperfusion status, and occlusion site were found to be independent predictors of MBE. These variables were combined to create the ACORNS grading scale. The areas under the curve in receiver operating curve analysis were 0.850 (95% CI 0.816 to 0.884), 0.874 (95% CI 0.821 to 0.926), and 0.785 (95% CI 0.740 to 0.829) for the training, internal validation, and external validation cohorts, respectively, indicating good discriminative performance in the validation cohorts.

CONCLUSIONS

The ACORNS grading scale is an accurate and easily applicable model for the prediction of the development of MBE after EVT.

Location-specific ASPECTS does not improve Outcome Prediction in Large Vessel Occlusion compared to Cumulative ASPECTS

PURPOSE

Individual regions of the Alberta Stroke Programme Early CT Score (ASPECTS) may contribute differently to the clinical symptoms in large vessel occlusion (LVO). Here, we investigated whether the predictive performance on clinical outcome can be increased by considering specific ASPECTS subregions.

METHODS

A consecutive series of patients with LVO affecting the middle cerebral artery territory and subsequent endovascular treatment (EVT) between January 2015 and July 2020 was analyzed, including affected ASPECTS regions. A multivariate logistic regression was performed to assess the individual impact of ASPECTS regions on good clinical outcome (defined as modified Rankin scale after 90 days of 0-2). Machine-learning-driven logistic regression models were trained (training = 70%, testing = 30%) to predict good clinical outcome using i) cumulative ASPECTS and ii) location-specific ASPECTS, and their performance compared using deLong's test. Furthermore, additional analyses using binarized as well as linear clinical outcomes using regression and machine-learning techniques were applied to thoroughly assess the potential predictive properties of individual ASPECTS regions and their combinations.

RESULTS

Of 1109 patients (77.3 years ± 11.6, 43.8% male), 419 achieved a good clinical outcome and a median NIHSS after 24 h of 12 (interquartile range, IQR 4-21). Individual ASPECTS regions showed different impact on good clinical outcome in the multivariate logistic regression, with strongest effects for insula (odds ratio, OR 0.56, 95% confidence interval, CI 0.42-0.75) and M5 (OR 0.53, 95% CI 0.29-0.97) regions. Accuracy (ACC) in predicting good clinical outcome of the test set did not differ between when considering i) cumulative ASPECTS and ii) location-specific ASPECTS (ACC = 0.619, 95% CI 0.58-0.64 vs. ACC = 0.629, 95% CI 0.60-0.65; p = 0.933).

CONCLUSION

Cumulative ASPECTS assessment in LVO remains a stable and reliable predictor for clinical outcome and is not inferior to a weighted (location-specific) ASPECTS assessment.

Predictors and outcome of malignant cerebral edema after successful reperfusion in anterior circulation stroke

BACKGROUND AND OBJECTIVE

Risk factors and predictors of malignant cerebral edema (MCE) after successful endovascular thrombectomy (EVT) were not fully explored. This study aimed to evaluate the incidence and risk factors of MCE after successful reperfusion.

METHODS

We retrospectively analyzed consecutive ischemic stroke patients who underwent EVT in our institution from November 2015 to April 2022. Patients who failed to achieve successful reperfusion (modified thrombolysis in cerebral infarction [mTICI]<2b) were excluded. Based on multivariate logistic models, the best-fit monogram was established. The discriminative performance was assessed by the receiver operating characteristics curve (ROC).

RESULTS

A total of 307 patients were included and 48 (15.6%) were diagnosed with MCE after successful reperfusion. Patients with MCE after successful reperfusion had a lower 3-month favorable outcome (15.2% versus 59.6%; p<0.001), a lower 3-month good outcome (17.4% versus 68.4%; p<0.001), and a higher rate of mortality at 3-month (54.3% versus 8.8%; p<0.001) compared with patients without MCE. Predictors of MCE after successful reperfusion included admission glucose level, baseline National Institutes of Health Stroke Scale (NIHSS) score, stroke etiology, occlusion site and puncture-to-reperfusion (PTR) time>120 min. The area under the curve (AUC) of the nomogram was 0.805 (95% CI, 0.756-0.847).

CONCLUSIONS

MCE after successful reperfusion is associated with poor outcome and mortality. A nomogram containing admission glucose level, baseline NIHSS score, stroke etiology, occlusion site and PTR time>120 min may predict the risk of MCE after successful reperfusion in patients with acute ischemic stroke and treated successfully with EVT.

From therapeutic nihilism to armamentarium: A meta-analysis of randomized clinical trials assessing safety and efficacy of endovascular therapy for acute large ischemic strokes

BACKGROUND

Three recent randomized clinical trials (RCTs) investigated the potential benefit of endovascular therapy (EVT) in acute ischemic stroke patients presenting with large infarcts. We aimed to confirm the safety and efficacy of EVT in patients presenting with large infarcts and provide more precise estimations of the treatment effects using study-level meta-analysis.

METHODS

Comprehensive search of MEDLINE database through PubMed till February 2023 was performed including RCTs only. The data were then extracted from the selected studies and pooled as risk ratio (RR) with 95% confidence interval (95% CI).

RESULTS

There were a total of 1005 patients across the three qualifying RCTs. Regarding the functional outcomes assessed by modified Rankin Scale (mRS) score, the analyzed data demonstrated statistically significant differences in favor of thrombectomy for both independent ambulatory status (mRS 0-3: RR = 1.78, 95% CI [1.28, 2.48], p = 0.0006) and functional independence (mRS 0-2: RR = 2.54, 95% CI [1.85, 3.48], p < 0.001). The analyzed data did not demonstrate any statistically significant differences between EVT and medical management alone in terms of 90-day mortality (RR = 0.95, 95% CI [0.78, 1.16], p = 0.61), symptomatic intracranial hemorrhage (RR = 1.83, 95% CI [0.95, 3.55], p = 0.07), and need for hemicraniectomy (RR = 1.22, 95% CI [0.43, 3.41], p = 0.71).

CONCLUSION

This study confirms the benefit of EVT on functional outcomes of patients presenting with large ischemic infarcts without significant differences in the rates of symptomatic intracranial hemorrhage, hemicraniectomy, or 90-day mortality.

Reversible CT Scan Hypodensity in Acute Ischemic Stroke Patient With Low Initial Alberta Stroke Program Early CT Score (ASPECTS) Following Endovascular Thrombectomy: A Case Report

According to current American and European guidelines, mechanical thrombectomy is recommended only for patients with an Alberta Stroke Program Early CT Score (ASPECTS) of 6 or higher. However, recent literature suggests that the potential benefits of reperfusion therapy should not be solely determined by baseline ASPECTS. In this case report, we present a young female patient with a low initial ASPECTS (4-5), who underwent mechanical thrombectomy and showed marked improvement in both CT imaging and clinical symptoms. Our findings potentially show that mechanical thrombectomy may be beneficial even for patients with an initial ASPECTS ≤ 5. These results may contribute to the growing evidence supporting the use of mechanical thrombectomy as a viable treatment option for acute ischemic stroke patients with low baseline ASPECTS.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Association Between Net Water Uptake and Functional Outcome in Patients With Low ASPECTS Brain Lesions: Results From the I-LAST Study

BACKGROUND AND OBJECTIVES

The effect of mechanical thrombectomy (MT) on functional outcome in patients with ischemic stroke with low ASPECTS is still uncertain. ASPECTS rating is based on the presence of ischemic hypoattenuation relative to normal; however, the degree of hypoattenuation, which directly reflects net uptake of water, is currently not considered an imaging biomarker in stroke triage. We hypothesized that the effect of thrombectomy on functional outcome in low ASPECTS patients depends on early lesion water uptake.

METHODS

For this multicenter observational study, patients with anterior circulation stroke with ASPECTS ≤5 were consecutively analyzed. Net water uptake (NWU) was assessed as a quantitative imaging biomarker in admission CT. The primary end point was the rate of favorable functional outcome defined as modified Rankin Scale score 0-3 at day 90. The effect of recanalization on functional outcome was analyzed according to the degree of NWU within the early infarct lesion.

RESULTS

A total of 254 patients were included, of which 148 (58%) underwent MT. The median ASPECTS was 4 (interquartile range [IQR] 3-5), and the median NWU was 11.4% (IQR 8.9%-15.1%). The rate of favorable outcome was 27.6% in patients with low NWU (<11.4%) vs 6.3% in patients with high NWU (≥11.4%; p < 0.0001). In multivariable logistic regression analysis, NWU was an independent predictor of outcome, whereas vessel recanalization (modified thrombolysis in cerebral infarction ≥2b) was only significantly associated with better outcomes if NWU was lower than 12.6%. In inverse-probability weighting analysis, recanalization was associated with 20.7% (p = 0.01) increase in favorable outcome in patients with low NWU compared with 9.1% (p = 0.06) in patients with high NWU.

DISCUSSION

Early NWU was independently associated with clinical outcome and might serve as an indicator of futile MT in low ASPECTS patients. NWU could be tested as a tool to select low ASPECTS patients for MT.

TRIAL REGISTRATION INFORMATION

The study is registered within the ClinicalTrials.gov Protocol Registration and Results System (NCT04862507).

Large mismatch profile predicts rapidly progressing brain edema in acute anterior circulation large vessel occlusion patients undergoing endovascular thrombectomy

Background

Brain edema is a severe complication in patients with large vessel occlusion (LVO) that can reduce the effectiveness of endovascular therapy (EVT). This study aimed to investigate the association of the perfusion profile at baseline computed tomography (CT) perfusion with rapidly progressing brain edema (RPBE) after EVT in patients with acute anterior LVO.

Methods

We retrospectively reviewed consecutive data collected from 149 patients with anterior LVO who underwent EVT at our center. Brain edema was measured by the swelling score (0-6 score), and RPBE was defined as the swelling score increased by more than 2 scores within 24 h after EVT. We investigated the effect of RPBE on poor outcomes [National Institute of Health Stroke Scale (NIHSS) score and modified Rankin scale (mRS) score at discharge, the occurrence of hemorrhagic transformation, and mortality rate in the hospital] using the Mann-Whitney U-test and chi-square test. A multivariate logistic regression model was used to assess the relationship between perfusion imaging parameters and RPBE occurrence.

Results

Overall, 39 patients (26.2%) experienced RPBE after EVT. At discharge, RPBE was associated with higher NIHSS scores (Z = 3.52, 95% CI 2.0-12.0, P < 0.001) and higher mRS scores (Z = 3.67, 95% CI 0.0-1.0, P < 0.001) including the more frequent occurrence of hemorrhagic transformation (χ² = 22.17, 95% CI 0.29-0.59, P < 0.001) and higher mortality rates in hospital (χ² = 9.54, 95% CI 0.06-0.36, P = 0.002). Univariate analysis showed that intravenous thrombolysis, baseline ischemic core volume, and baseline mismatch ratio correlated with RPBE (all P < 0.05). After dividing the mismatch ratio into quartiles and performing a chi-square test between quartiles, we found that the occurrence of RPBE in Q4 (mismatch ratio > 11.3) was significantly lower than that in Q1 (mismatch ratio ≤ 3.0) (P < 0.05). The result of multivariate logistic regression analysis showed that compared with baseline mismatch ratio <5.1, baseline mismatch ratio between 5.1 and 11.3 (OR:3.85, 95% CI 1.06-14.29, P = 0.040), and mismatch ratio >11.3 (OR:5.26, 95% CI 1.28-20.00, P = 0.021) were independent protective factors for RPBE.

Conclusion

In patients with anterior circulation LVO stroke undergoing successful EVT, a large mismatch ratio at baseline is a protective factor for RPBE, which is associated with poor outcomes.

Automated Estimation of Quantitative Lesion Water Uptake as a Prognostic Biomarker for Patients with Ischemic Stroke and Large-Vessel Occlusion

BACKGROUND AND PURPOSE

Net water uptake is qualified as an imaging marker of brain edema. We aimed to investigate the ability of net water uptake to predict 90-day functional outcome in patients with acute ischemic stroke and large-vessel occlusion.

MATERIALS AND METHODS

A total of 295 consecutive patients were retrospectively enrolled. Automated ASPECTS-net water uptake was calculated on the admission CT. The relationship between ASPECTS-net water uptake and 90-day neurologic outcome was assessed. The independent predictors of favorable outcome (mRS score ≤2) were assessed using multivariate logistic regression analysis and receiver operating characteristic curves and stratified by the ASPECTS.

RESULTS

Favorable 90-day outcomes were observed in 156 (52.9%) patients. ASPECTS-net water uptake (OR, 0.79; 95% CI, 0.70-0.90), NIHSS scores (OR, 0.91; 95% CI, 0.87-0.96), age (OR, 0.96; 95% CI, 0.94-0.99), and vessel recanalization (OR, 7.78; 95% CI, 3.96-15.29) were independently associated with favorable outcomes at 90 days (all, P < .01). A lower ASPECTS-net water uptake independently predicted a good prognosis, even in the subgroup of patients with low ASPECTS (≤5) (P < .05). An outcome-prediction model based on these variables yielded an area under the receiver operating characteristic curve of 0.856 (95% CI, 0.814-0.899; sensitivity, 76.3%; specificity, 81.3%).

CONCLUSIONS

ASPECTS-net water uptake could independently predict 90-day neurologic outcomes in patients with acute ischemic stroke and large-vessel occlusion. Integrating ASPECTS-net water uptake with clinical models could improve the efficiency of outcome stratification.

Benefit and risk of intravenous alteplase in patients with acute large vessel occlusion stroke and low ASPECTS

BACKGROUND

The benefit of best medical treatment including intravenous alteplase (IVT) before mechanical thrombectomy (MT) in patients with acute ischemic stroke and extensive early ischemic changes on baseline CT remains uncertain. The purpose of this study was to evaluate the benefit of IVT for patients with low ASPECTS (Alberta Stroke Programme Early CT Score) compared with patients with or without MT.

METHODS

This multicenter study pooled consecutive patients with anterior circulation acute stroke and ASPECTS≤5 to analyze the impact of IVT on functional outcome, and to compare bridging IVT with direct MT. Functional endpoints were the rates of good (modified Rankin Scale (mRS) score ≤2) and very poor (mRS ≥5) outcome at day 90. Safety endpoint was the occurrence of symptomatic intracranial hemorrhage (sICH).

RESULTS

429 patients were included. 290 (68%) received IVT and 168 (39%) underwent MT. The rate of good functional outcome was 14.4% (95% CI 7.1% to 21.8%) for patients who received bridging IVT and 24.4% (95% CI 16.5% to 32.2%) for those who underwent direct MT. The rate of sICH was significantly higher in patients with bridging IVT compared with direct MT (17.8% vs 6.4%, p=0.004). In multivariable logistic regression analysis, IVT was significantly associated with very poor outcome (OR 2.22, 95% CI 1.05 to 4.73, p=0.04) and sICH (OR 3.44, 95% CI 1.18 to 10.07, p=0.02). Successful recanalization, age, and ASPECTS were associated with good functional outcome.

CONCLUSIONS

Bridging IVT in patients with low ASPECTS was associated with very poor functional outcome and an increased risk of sICH. The benefit of this treatment should therefore be carefully weighed in such scenarios. Further randomized controlled trials are required to validate our findings.

Impact of edema formation on functional outcome in pediatric stroke patients

BACKGROUND

Quantitative lesion net water uptake (NWU) has been described as an imaging biomarker reflecting vasogenic edema as an early indicator of infarct progression. We hypothesized that edema formation measured by NWU is higher in children compared to adults but despite this functional outcome may be better in children.

METHODS

This study analyzed children enrolled in the Save ChildS Study who had baseline and follow-up computed tomography available and the data were compared to adult patients.

RESULTS

Some 207 patients, of whom 13 were children and 194 were adults, were analyzed. Median NWU at baseline was 7.8% (IQR: 4.3-11.3), and there were no significant differences between children and adults (7.5% vs. 7.8%; p = 0.87). The early edema progression rate was 3.0%/h in children and 2.3%/h in adults. Median ΔNWU was 15.1% in children and 10.5% in adults. Children had significantly more often excellent (mRS 0-1; children 10/13 = 77% vs. adults 28/196 = 14%; p < 0.0001) and favorable clinical outcomes (mRS 0-2, 12/13 = 92% vs. 39/196 = 20%; p < 0.0001).

CONCLUSIONS

In this study, clinical outcomes in children with large vessel occlusion strokes were better than in adults despite similar clinical and imaging characteristics and similar edema formation. This may be impacted by the generally better outcomes of children after strokes but may demonstrate that the degree of early ischemic changes using Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and edema progression rate may not be a reason for exclusion from endovascular thrombectomy.

Association between Infarct Location and Hemorrhagic Transformation of Acute Ischemic Stroke following Successful Recanalization after Mechanical Thrombectomy

BACKGROUND AND PURPOSE

The association between infarct location and hemorrhagic transformation of acute ischemic stroke after mechanical thrombectomy is not understood. We aimed to evaluate the association between CTP-based ischemic core variables at admission and hemorrhagic transformation after a successful thrombectomy.

MATERIALS AND METHODS

We retrospectively analyzed patients who underwent endovascular thrombectomy for acute anterior circulation large-vessel occlusion between October 2019 and June 2021. We enrolled 146 patients with visible ischemic core on pretreatment CTP who had successful reperfusion. The ischemic core infarct territories were classified into the cortical and subcortical areas and then qualitatively and quantitatively analyzed by CTP. Logistic regression and receiver operating characteristic curve analyses were performed to determine the association between ischemic core variables and hemorrhagic transformation.

RESULTS

Of the 146 patients analyzed, 72 (49.3%) had hemorrhagic transformation and 23 (15.8%) had symptomatic intracerebral hemorrhage. Multivariate analysis showed that subcortical infarcts were independently associated with hemorrhagic transformation (OR, 8.06; 95% CI, 2.31-28.10; P = .001) and subcortical infarct volume was independently linked to symptomatic intracerebral hemorrhage (OR, 1.05; 95% CI, 1.01-1.09; P = .039). The receiver operating characteristic curve indicated that subcortical infarcts can predict hemorrhagic transformation accurately (area under the curve = 0.755; 95% CI, 0.68-0.82; P < .001) and subcortical infarct volume can predict symptomatic intracerebral hemorrhage (area under the curve = 0.694; 95% CI, 0.61-0.77; P = .002).

CONCLUSIONS

Subcortical infarcts seen on CTP at admission are associated with hemorrhagic transformation in patients after successful thrombectomy, and subcortical infarct volume may influence the risk of symptomatic intracerebral hemorrhage.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Endovascular treatment for anterior circulation large-vessel occlusion ischemic stroke with low ASPECTS: a systematic review and meta-analysis

BACKGROUND

Endovascular treatment (EVT) for acute ischemic stroke (AIS) patients presenting with Alberta Stroke Program Early CT Score (ASPECTS) 0-5 has not yet proven safe and effective by clinical trials.

OBJECTIVES

The aim of the study was to assess whether EVT in AIS patients presenting with low ASPECTS is beneficial.

DESIGN

Systematic review and meta-analysis of available studies in accordance with the PRISMA statement.

DATA SOURCES AND METHODS

We have searched MEDLINE, the Cochrane Central Register of Controlled Trials, and reference lists of articles published until 28 May 2022 with the aim to calculate (1) modified Rankin scale (mRS) score 0-3 at 3 months, (2) mRS score 0-2 at 3 months, (3) symptomatic intracranial hemorrhage (sICH), and (3) mortality at 3 months.

RESULTS

Overall, 24 eligible studies were included in the meta-analysis, comprising a total of 2539 AIS patients with ASPECTS 0-5 treated with EVT. The pooled proportion of EVT-treated patients achieving mRS 0-3 at 3 months was calculated at 38.4%. The pooled proportion of EVT-treated patients achieving mRS 0-2 at 3 months was 25.7%. Regarding safety outcomes, sICH occurred in 12.8% of patients. The 3-month pooled mortality was 30%. In pairwise meta-analysis, patients treated with EVT had a higher likelihood of achieving mRS 0-3 at 3 months compared with patients treated with best medical therapy (BMT, OR: 2.41). sICH occurred more frequently in EVT-treated patients compared with the BMT-treated patients (OR: 2.30). Mortality at 3 months was not different between the two treatment groups (OR: 0.71).

CONCLUSION

EVT may be beneficial for AIS patients with low baseline ASPECTS despite an increased risk for sICH. Further data from randomized-controlled clinical trials are needed to elucidate the role of EVT in this subgroup of AIS patients.

REGISTRATION

The protocol has been registered in the International Prospective Register of Ongoing Systematic Reviews PROSPERO; Registration Number: CRD42022334417.

Association of Thrombectomy With Functional Outcome for Patients With Ischemic Stroke Who Presented in the Extended Time Window With Extensive Signs of Infarction

IMPORTANCE

Only limited data are available about a potential benefit associated with endovascular treatment (EVT) for patients with ischemic stroke presenting in the extended time window who also show signs of extensive infarction.

OBJECTIVE

To assess the association of recanalization after EVT with functional outcomes for patients with ischemic stroke presenting in the extended time window who also show signs of extensive infarction.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, multicenter cohort study included patients enrolled in the German Stroke Registry-Endovascular Treatment with an Alberta Stroke Program Early CT Score (ASPECTS) of 5 or less who presented between 6 and 24 hours after stroke onset and underwent computed tomography and subsequent EVT between July 1, 2015, and December 31, 2019.

MAIN OUTCOMES AND MEASURES

The primary end point was a modified Rankin Scale (mRS) score of 3 or less at day 90. The association between recanalization (defined as the occurrence of a modified Thrombolysis in Cerebral Infarction Scale score of 2b or 3) and outcome was assessed using logistic regression and inverse probability weighting analysis.

INTERVENTION

Endovascular treatment.

RESULTS

Of 5853 patients, 285 (5%; 146 men [51%]; median age, 73 years [IQR, 62-81 years]) met the inclusion criteria and were analyzed. Of these 285 patients, 79 (27.7%) had an mRS score of 3 or less at day 90. The rate of successful recanalization was 75% (215 of 285) and was independently associated with a higher probability of reaching an mRS score of 3 or less (adjusted odds ratio, 4.39; 95% CI, 1.79-10.72; P < .001). In inverse probability weighting analysis, a modified Thrombolysis in Cerebral Infarction Scale score of 2b or 3 was associated with a 19% increase (95% CI, 9%-29%; P < .001) in the probability for an mRS score of 3 or more. Multivariable logistic regression analysis suggested a significant treatment benefit associated with vessel recanalization in a time window of up to 17.6 hours and ASPECTS of 3 to 5. The rate of secondary symptomatic intracerebral hemorrhage was 6.3% (18 of 285).

CONCLUSIONS AND RELEVANCE

In this cohort study reflecting daily clinical practice, vessel recanalization for patients with a low ASPECTS and extended time window was associated with better functional outcomes in a time window up to 17.6 hours and ASPECTS of 3 to 5. The results of this study encourage current randomized clinical trials to enroll patients with a low ASPECTS, even within the extended time window.

ASPECTS-based net water uptake predicts poor reperfusion and poor clinical outcomes in patients with ischemic stroke

OBJECTIVE

To investigate the value of automated Alberta Stroke Program Early CT Score (ASPECTS)-based net water uptake (NWU) to predict tissue-level reperfusion status and 90-day functional outcomes in acute ischemic stroke (AIS) patients after reperfusion therapy.

METHODS

One hundred and twelve patients with AIS who received reperfusion therapy were enrolled. ASPECTS-NWU was calculated from admission CT (NWU_admission) and follow-up CT (NWU_FCT), and the difference (ΔNWU) was calculated. Tissue-level reperfusion status was evaluated via follow-up arterial spin labeling imaging. The relationship between ASPECTS-NWU and tissue-level reperfusion was evaluated. Predictors of 90-day unfavorable outcomes (modified Rankin Scale score > 2) were assessed by multivariate logistic regression analysis and receiver operating characteristic (ROC) curves.

RESULTS

Poor reperfusion was observed in 40 patients (35.7%) after therapy. Those patients had significantly elevated NWU_FCT (median, 14.15% vs. 8.08%, p = 0.018) and higher ΔNWU (median, 4.12% vs. -2.03%, p < 0.001), compared to patients with good reperfusion. High ΔNWU was a significant marker of poor reperfusion despite successful recanalization. National Institutes of Health Stroke Scale score at admission (odds ratio [OR], 1.11; 95% confidence interval [CI] 1.03-1.20, p = 0.007) and ΔNWU (OR, 1.07; 95% CI 1.02-1.13, p = 0.008) were independently associated with unfavorable outcomes. An outcome prediction model including both parameters yields an area under the curve of 0.762 (sensitivity 70.3%, specificity, 84.2%).

CONCLUSIONS

Elevated NWU_FCT and higher ΔNWU were associated with poor tissue-level reperfusion after therapy. Higher ΔNWU was an independent predictor of poor reperfusion and unfavorable neurological outcomes despite successful recanalization.

KEY POINTS

• ASPECTS-NWU may provide pathophysiological information about tissue-level reperfusion status and offer prognostic benefits for patients with AIS after reperfusion therapy. • Elevated NWU_FCT and higher ΔNWU were correlated with poor tissue-level reperfusion after therapy. • A higher ΔNWU is an independent predictor of poor reperfusion and 90-day unfavorable outcomes despite successful recanalization.

Post-ASPECTS based on hyperdensity in NCCT immediately after thrombectomy is an ultra-early predictor of hemorrhagic transformation and prognosis

Background and Purpose

Almost half of the patients exhibit futile recanalization after thrombectomy; however, the early postoperative predictors of futile recanalization remain unclear. We analyzed the relationship of post-thrombectomy ASPECTS (Post-ASPECTS) with 90-day prognosis and hemorrhagic transformation (HT).

Methods

We collected data from patients with acute ischemic stroke (AIS) with anterior-circulation large vessel occlusion (ACLVO) who were treated via thrombectomy within 10 h in 3 hospitals. Successful endovascular recanalization was achieved (modified thrombolysis in cerebral ischemia [mTICI] 2b/3). Non-contrast computed tomography (NCCT) examination was performed immediately (within 1 h) after thrombectomy. Post-ASPECTS were scored based on the brain parenchymal hyperdensity in NCCT according to the ASPECTS scoring method. HT was defined according to the ECASS II classification criteria. Linear correlation, logistic regression, and receiver operating characteristic curve analyses were used to determine the influencing factors and best predictive value of 90-day prognosis, 90-day death, and HT.

Results

A total of 231 patients were enrolled. The good prognosis rate, mortality rate, and HT rate were 57.1, 9.5, and 38.3%, respectively. The Post-ASPECTS affected poor prognosis, death, and HT. The best predictive value of Post-ASPECTS for poor prognosis, death, and HT was 7. The specificities of Post-ASPECTS for predicting HT, poor prognosis, and death were 87.6% (AUC, 0.811; P &lt; 0.001), 87.1% (AUC, 0.768; P &lt; 0.001), and 73.7% (AUC, 0.748; P &lt; 0.001), with positive predictive values of 74.2, 75.7, and 21.4%, respectively.

Conclusion

Post-ASPECTS predicted 90-day prognosis, death, and HT with high specificity and high positive predictive value in patients with AIS with ACLVO. Post-ASPECTS may be an ultra-early predictor of prognosis after thrombectomy.

Association Between Post-procedure Cerebral Blood Flow Velocity and Severity of Brain Edema in Acute Ischemic Stroke With Early Endovascular Therapy

Objectives

We aimed to investigate the association between post-procedure cerebral blood flow velocity (CBFV) and severity of brain edema in patients with acute ischemic stroke (AIS) who received early endovascular therapy (EVT).

Methods

We retrospectively included patients with AIS who received EVT within 24 h of onset between February 2016 and November 2021. Post-procedure CBFV of the middle cerebral artery was measured in the affected and the contralateral hemispheres using transcranial Doppler ultrasound. The severity of brain edema was measured using the three-level cerebral edema grading from the Safe Implementation of Thrombolysis in Stroke-Monitoring Study, with grades 2–3 indicating severe brain edema. The Association between CBFV parameters and severity of brain edema was analyzed.

Results

A total of 101 patients (mean age 64.2 years, 65.3% male) were included, of whom 56.3% (57/101) suffered brain edema [grade 1, 23 (22.8%); grade 2, 10 (9.9%); and grade 3, 24 (23.8%)]. Compared to patients with non-severe brain edema, patients with severe brain edema had lower affected/contralateral ratios of systolic CBFV (median 1 vs. 1.2, P = 0.020) and mean CBFV (median 0.9 vs. 1.3, P = 0.029). Multivariate logistic regression showed that severe brain edema was independently associated with affected/contralateral ratios of systolic CBFV [odds ratio (OR) = 0.289, 95% confidence interval (CI): 0.069–0.861, P = 0.028] and mean CBFV (OR = 0.278, 95% CI: 0.084–0.914, P = 0.035) after adjusting for potential confounders.

Conclusion

Post-procedure affected/contralateral ratio of CBFV may be a promising predictor of brain edema severity in patients with AIS who received early EVT.

By and Large, Thrombectomy in Large Core Is a Palpable Reality

Our Japanese colleagues deserve much praise for finishing the first randomized clinical trial of thrombectomy in Alberta Stroke Program Early CT Score 3 to 5 patients showing an impressive therapy effect of thrombectomy. The predominant use of magnetic resonance imaging for patient selection, the low rate of alteplase therapy and its low dose limit direct comparisons with patients treated outside of Japan. Another limitation is the lack of benefit when using the traditional metric–modified Rankin Scale score 0–2. We consider the results of RESCUE-Japan LIMIT encouraging and a clear motivation to continue and complete other studies.

The Cerebral Collateral Cascade: Comprehensive Blood Flow in Ischemic Stroke

BACKGROUND AND OBJECTIVES

Robust cerebral collaterals are associated with favorable outcomes in patients with acute ischemic stroke due to large vessel occlusion treated by thrombectomy. However, collateral status assessment mostly relies on single imaging biomarkers and a more comprehensive holistic approach may provide deeper insights into the biology of collateral perfusion on medical imaging. Comprehensive collateralization is defined as blood flow of cerebral arteries through the brain tissue and into draining veins. We hypothesized that a comprehensive analysis of the cerebral collateral cascade (CCC) on an arterial, tissue, and venous level would predict clinical and radiologic outcomes.

METHODS

This was a multicenter retrospective cohort study of patients with acute stroke undergoing thrombectomy triage. CCC was determined by quantifying pial arterial collaterals, tissue-level collaterals, and venous outflow (VO). Pial arterial collaterals were determined by CT angiography; tissue-level collaterals were assessed on CT perfusion. VO was assessed on CT angiography using the cortical vein opacification score. Three groups were defined: CCC+ (good pial collaterals, tissue-level collaterals, and VO), CCC- (poor pial collaterals, tissue-level collaterals, and VO), and CCCmixed (the remainder of the patients). Primary outcome was functional independence (modified Rankin Scale score 0-2) at 90 days. Secondary outcome was final infarct volume.

RESULTS

A total of 647 patients met inclusion criteria: 176 CCC+, 345 CCCmixed, and 126 CCC-. Multivariable ordinal logistic regression showed that CCC+ predicted good functional outcomes (odds ratio [OR] 18.9 [95% CI 8-44.5]; p < 0.001) compared with CCC- and CCCmixed. CCCmixed patients likely had better functional outcomes compared with CCC- patients (OR 2.5 [95% CI 1.2-5.4]; p = 0.014). Quantile regression analysis (50th percentile) showed that CCC+ (β -78.5, 95% CI -96.0 to -61.1; p < 0.001) and CCCmixed (β -64.0, 95% CI -82.4 to -45.6; p < 0.001) profiles were associated with considerably lower final infarct volumes compared with CCC- profiles.

DISCUSSION

Comprehensive assessment of the collateral blood flow cascade in patients with acute stroke is a strong predictor of clinical and radiologic outcomes in patients treated by thrombectomy.

Decision-making strategies for reperfusion therapies: navigating through stroke trials gaps

Despite there being a robust amount of literature and numerous randomized clinical trials regarding acute ischemic stroke treatment, the trials have not included some frequent controversial situations for which decision-making strategies are an urgent and unmet need in clinical practice. This article tries to summarize the current evidence about some selected situations (mechanical thrombectomy in low ASPECTS, low NIHSS with proximal occlusion, acute basilar occlusion, distal and medium vessel occlusion, among others), make suggestions on how to approach them in clinical practice and show what to expect in acute stroke research in the near future.

Venous Flow Profiles on Perfusion CT are Associated with Futile Recanalization After Thrombectomy

Background and Purpose

Robust venous outflow (VO) reflects favourable tissue reperfusion in acute ischaemic stroke (AIS) patients with large vessel occlusion (LVO). We aimed to investigate the association of the venous outflow profile on computed tomographic perfusion (CTP) and futile recanalization in anterior circulation AIS patients with LVO after thrombectomy.

Methods

This was a retrospective study of consecutive AIS patients due to anterior circulation LVO who underwent CTP before thrombectomy. Patients who achieved successful recanalization defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score of 2b or 3 after thrombectomy were included. Based on the venous time-intensity curve of CTP, the peak time of venous outflow (PTV), total venous outflow time (TVT), and difference value of arteriovenous peak time (D-value) were recorded. A modified mRS score of 3-6 at 3 months was regarded as futile recanalization (FR). Logistic regression analysis was applied to assess risk factors for FR. We used receiver operating characteristic curves (ROCs) to evaluate the predictive value of venous outflow time parameters based on VO for FR.

Results

Eighty patients were included; 35 (43.8%) achieved good functional outcomes, and 45 (56.3%) had unfavourable functional outcomes, that is, FR. Adjusting confounding factors, binary stepwise logistic regression analysis showed that delayed PTV was independently associated with FR (odds ratio, 1.374 [95% CI, 1.093-1.726], P = 0.007). ROCs indicated that PTV effectively predicted unfavourable outcomes at 3 months (area under the curve (AUC) = 0.729, p< 0.001). The combined model was a powerful predictor of FR with an AUC of 0.824 and a cut-off value of 0.631 (p< 0.001).

Conclusion

Delayed PTV is independently related to FR in anterior circulation AIS patients with LVO achieving successful recanalization after thrombectomy. Our results highlight that the time of VO may be a potential marker for FR.

Cerebral Hypoperfusion Intensity Ratio Is Linked to Progressive Early Edema Formation

The hypoperfusion intensity ratio (HIR) is associated with collateral status and reflects the impaired microperfusion of brain tissue in patients with acute ischemic stroke and large vessel occlusion (AIS-LVO). As a deterioration in cerebral blood flow is associated with brain edema, we aimed to investigate whether HIR is correlated with the early edema progression rate (EPR) determined by the ischemic net water uptake (NWU) in a multicenter retrospective analysis of AIS-LVO patients anticipated for thrombectomy treatment. HIR was automatically calculated as the ratio of time-to-maximum (TMax) > 10 s/(TMax) > 6 s. HIRs < 0.4 were regarded as favorable (HIR+) and ≥0.4 as unfavorable (HIR−). Quantitative ischemic lesion NWU was delineated on baseline NCCT images and EPR was calculated as the ratio of NWU/time from symptom onset to imaging. Multivariable regression analysis was used to assess the association of HIR with EPR. This study included 731 patients. HIR+ patients exhibited a reduced median NWU upon admission CT (4% (IQR: 2.1−7.6) versus 8.2% (6−10.4); p < 0.001) and less median EPR (0.016%/h (IQR: 0.007−0.04) versus 0.044%/h (IQR: 0.021−0.089; p < 0.001) compared to HIR− patients. Multivariable regression showed that HIR+ (β: 0.53, SE: 0.02; p = 0.003) and presentation of the National Institutes of Health Stroke Scale (β: 0.2, SE: 0.0006; p = 0.001) were independently associated with EPR. In conclusion, favorable HIR was associated with lower early edema progression and decreased ischemic edema formation on baseline NCCT.

Correlation Between Computed Tomography-Based Tissue Net Water Uptake and Volumetric Measures of Cerebral Edema After Reperfusion Therapy

BACKGROUND

Cerebral edema after large hemispheric infarction is associated with poor functional outcome and mortality. Net water uptake (NWU) quantifies the degree of hypoattenuation on unenhanced-computed tomography (CT) and is increasingly used to measure cerebral edema in stroke research. Hemorrhagic transformation and parenchymal contrast staining after thrombectomy may confound NWU measurements. We investigated the correlation of NWU measured postthrombectomy with volumetric markers of cerebral edema and association with functional outcomes.

METHODS

In a pooled individual patient level analysis of patients presenting with anterior circulation large hemispheric infarction (core 80-300 mL or Alberta Stroke Program Early CT Score ≤5) in the HERMES (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke trials) data set, cerebral edema was defined as the volumetric expansion of the ischemic hemisphere expressed as a ratio to the contralateral hemisphere(rHV). NWU and midline-shift were compared with rHV as the reference standard on 24-hour follow-up CT, adjusted for hemorrhagic transformation and the use of thrombectomy. Association between edema markers and day 90 functional outcomes (modified Rankin Scale) was assessed using ordinal logistic regression.

RESULTS

Overall (n=144), there was no correlation between NWU and rHV (r_s=0.055, P=0.51). In sub-group analyses, a weak correlation between NWU with rHV was observed after excluding patients with any degree of hemorrhagic transformation (r_s=0.211, P=0.015), which further improved after excluding thrombectomy patients (r_s=0.453, P=0.001). Midline-shift correlated strongly with rHV in all sub-group analyses (r_s>0.753, P=0.001). Functional outcome at 90 days was negatively associated with rHV (adjusted common odds ratio, 0.46 [95% CI, 0.32-0.65]; P<0.001) and midline-shift (adjusted common odds ratio, 0.85 [95% CI, 0.78-0.92]; P<0.001) but not NWU (adjusted common odds ratio, 1.00 [95% CI, 0.97-1.03]; P=0.84), adjusted for age, baseline National Institutes of Health Stroke Scale, and thrombectomy. Prognostic performance of NWU improved after excluding patients with hemorrhagic transformation and thrombectomy (adjusted odds ratio, 0.90 [95% CI, 0.80-1.02]; P=0.10).

CONCLUSIONS

NWU correlated poorly with conventional markers of cerebral edema and was not associated with clinical outcome in the presence of hemorrhagic transformation and thrombectomy. Measuring NWU postthrombectomy requires validation before implementation into clinical research. At present, the use of NWU should be limited to baseline CT, or follow-up CT only in patients without hemorrhagic transformation or treatment with thrombectomy.

FLAIR vascular hyperintensities predict functional outcome after endovascular thrombectomy in patients with large ischemic cores

OBJECTIVES

To establish whether collateral circulation was associated with functional outcome in stroke patients with large infarct size (Alberta Stroke Program Early CT Score [ASPECTS] ≤ 5) undergoing endovascular thrombectomy (EVT) METHODS: Consecutive patients with acute ischemic stroke due to large-vessel occlusion in the anterior circulation and an ASPECTS of ≤ 5 were analyzed. Quantification of collateral circulation was performed using a fluid-attenuated inversion recovery vascular hyperintensity (FVH)-ASPECTS rating system (score ranging from 0 [no FVH] to 7 [FVHs abutting all ASPECTS cortical areas]) by two independent neuroradiologists. Good functional outcome was defined by modified Rankin Scale (mRS) score of 0 to 3 at 3 months. We determined the association between FVH score and clinical outcome using multivariable regression analyses.

RESULTS

A total of 139 patients (age, 63.1 ± 20.8 years; men, 51.8%) admitted between March 2012 and December 2017 were included. Good functional outcome (mRS 0-3) was observed in 65 (46.8%) patients, functional independence (mRS 0-2) was achieved in 43 (30.9%) patients, and 33 (23.7%) patients died at 90 days. The median FVH score was 4 (IQR, 3-5). FVH score was independently correlated with good outcome (adjusted OR = 1.41 [95% CI, 1.03-1.92]; p = 0.03 per 1-point increase).

CONCLUSIONS

In stroke patients with large-volume infarcts, good collaterals as measured by the FVH-ASPECTS rating system are associated with improved outcomes and may help select patients for reperfusion therapy.

KEY POINTS

• Endovascular thrombectomy can allow almost 1 in 2 patients with large infarct cores to achieve good functional outcome (modified Rankin Scale [mRS] of 0-3) and 1 in 3 patients to regain functional independence (mRS 0-2) at 3 months. • The extent of FVH score (as reflected by FLAIR vascular hyperintensity [FVH]-Alberta Stroke Program Early CT Score [ASPECTS] values) is associated with functional outcome at 3 months in this patient group.

New imaging score for outcome prediction in basilar artery occlusion stroke

OBJECTIVE

In ischemic posterior circulation stroke, the utilization of standardized image scores is not established in daily clinical practice. We aimed to test a novel imaging score that combines the collateral status with the rating of the posterior circulation Acute Stroke Prognosis Early CT score (pcASPECTS). We hypothesized that this score (pcASCO) predicts functional outcome and malignant cerebellar edema (MCE).

METHODS

Ischemic stroke patients with acute BAO who received multimodal-CT and underwent thrombectomy on admission at two comprehensive stroke centers were analyzed. The posterior circulation collateral score by van der Hoeven et al was added to the pcASPECTS to define pcASCO as a 20-point score. Multivariable logistic regression analyses were performed to predict functional independence at day 90, assessed using modified Rankin Scale scores, and occurrence of MCE in follow-up CT using the established Jauss scale score as endpoints.

RESULTS

A total of 118 patients were included, of which 84 (71%) underwent successful thrombectomy. Based on receiver operating characteristic curve analysis, pcASCO ≥ 14 classified functional independence with higher discriminative power (AUC: 0.83, 95%CI: 0.71-0.91) than pcASPECTS (AUC: 0.74). In multivariable logistic regression analysis, pcASCO was significantly and independently associated with functional independence (aOR: 1.91, 95%CI: 1.25-2.92, p = 0.003), and MCE (aOR: 0.71, 95%CI: 0.53-0.95, p = 0.02).

CONCLUSION

The pcASCO could serve as a simple and feasible imaging tool to assess BAO stroke patients on admission and might be tested as a complementary tool to select patients for thrombectomy in uncertain situations, or to predict clinical outcome.

KEY POINTS

• The neurological assessment of basilar artery occlusion stroke patients can be challenging and there are yet no validated imaging scores established in daily clinical practice. • The pcASCO combines the rating of early ischemic changes with the status of the intracranial posterior circulation collaterals. • The pcASCO showed high diagnostic accuracy to predict functional outcome and malignant cerebellar edema and could serve as a simple and feasible imaging tool to support treatment selection in uncertain situations, or to predict clinical outcome.

Effect of Intravenous Alteplase on Functional Outcome and Secondary Injury Volumes in Stroke Patients with Complete Endovascular Recanalization

Intravenous thrombolytic therapy with alteplase (IVT) is a standard of care in ischemic stroke, while recent trials investigating direct endovascular thrombectomy (EVT) approaches showed conflicting results. Yet, the effect of IVT on secondary injury volumes in patients with complete recanalization has not been analyzed. We hypothesized that IVT is associated with worse functional outcome and aggravated secondary injury volumes when administered to patients who subsequently attained complete reperfusion after EVT. Anterior circulation ischemic stroke patients with complete reperfusion after thrombectomy defined as thrombolysis in cerebral infarctions (TICI) scale 3 after thrombectomy admitted between January 2013–January 2021 were analyzed. Primary endpoints were the proportion of patients with functional independence defined as modified Rankin Scale (mRS) score 0–2 at day 90, and secondary injury volumes: Edema volume in follow-up imaging measured using quantitative net water uptake (NWU), and the rate of symptomatic intracerebral hemorrhage (sICH). A total of 219 patients were included and 128 (58%) patients received bridging IVT before thrombectomy. The proportion of patients with functional independence was 28% for patients with bridging IVT, and 34% for patients with direct thrombectomy (p = 0.35). The rate of sICH was significantly higher after bridging IVT (20% versus 7.7%, p = 0.01). Multivariable logistic and linear regression analysis confirmed the independent association of bridging IVT with sICH (aOR: 2.78, 95% CI: 1.02–7.56, p = 0.046), and edema volume (aOR: 8.70, 95% CI: 2.57–14.85, p = 0.006). Bridging IVT was associated with increased edema volume and risk for sICH as secondary injury volumes. The results of this study encourage direct EVT approaches, particularly in patients with higher likelihood of successful EVT.

Endovascular thrombectomy for acute ischemic stroke

This review describes the evolution of endovascular treatment for acute ischemic stroke, current state of the art, and the challenges for the next decade. The rapid development of endovascular thrombectomy (EVT), from the first attempts into standard of care on a global scale, is one of the major achievements in modern medicine. It was possible thanks to the establishment of a scientific framework for patient selection, assessment of stroke severity and outcome, technical development by dedicated physicians and the MedTech industry, including noninvasive imaging for patient selection, and radiological outcome evaluation. A series of randomized controlled trials on EVT in addition to intravenous thrombolytics, with overwhelmingly positive results for anterior circulation stroke within 6 h of onset regardless of patient characteristics with a number needed to treat of less than 3 for any positive shift in outcome, paved the way for a rapid introduction of EVT into clinical practice. Within the "extended" time window of 6-24 h, the effect has been even greater for patients with salvageable brain tissue according to perfusion imaging with a number needed to treat below 2. Even so, EVT is only available for a small portion of stroke patients, and successfully recanalized EVT patients do not always achieve excellent functional outcome. The major challenges in the years to come include rapid prehospital detection of stroke symptoms, adequate clinical and radiological diagnosis of severe ischemic stroke cases, enabling effective recanalization by EVT in dedicated angiosuites, followed by personalized post-EVT stroke care.

Persistent challenges in endovascular treatment decision-making for acute ischaemic stroke

PURPOSE OF REVIEW

Although endovascular treatment (EVT) is the gold standard for treating acute stroke patients with large vessel occlusion (LVO), multiple challenges in decision-making for specific conditions persist. Recent evidence on a selection of patient subgroups will be discussed in this narrative review.

RECENT FINDINGS

Two randomized controlled trials (RCTs) have been published in EVT of basilar artery occlusion (BAO). Large single arm studies showed promising results in Patients with low Alberta stroke program early CT score (ASPECTS) and more distal vessel occlusions. Recent data confirm patients with low National Institutes of Health Stroke Scale (NIHSS) despite LVO to represent a heterogeneous and challenging patient group.

SUMMARY

The current evidence does not justify withholding EVT from BAO patients as none of the RCTs showed any signal of superiority of BMT alone vs. EVT. Patients with low ASPECTS, more distal vessel occlusions and patients with low NIHSS scores should be included into RCTs if possible. Without participation in a RCT, patients should be selected for EVT based on age, severity and type of neurological impairment, time since symptom onset, location of the ischaemic lesion and perhaps also results of advanced imaging.

Consistent depiction of the acidic ischemic lesion with APT MRI-Dual RF power evaluation of pH-sensitive image in acute stroke

PURPOSE

Amide proton transfer-weighted (APTw) MRI provides a non-invasive pH-sensitive image, complementing perfusion and diffusion imaging for refined stratification of ischemic tissue. Although the commonly used magnetization transfer (MT) asymmetry (MTR_asym ) calculation reasonably corrects the direct RF saturation effect, it is susceptible to the concomitant semisolid macromolecular MT contribution. Therefore, this study aimed to compare the performance of MTR_asym and magnetization transfer and relaxation-normalized APT (MRAPT) analyses under 2 representative experimental conditions.

METHODS

Multiparametric MRI scans were performed in a rodent model of acute stroke, including relaxation, diffusion, and Z spectral images under 2 representative RF levels of 0.75 and 1.5 µT. Both MTR_asym and MRAPT values in the ischemic diffusion lesion and the contralateral normal areas were compared using correlation and Bland-Altman tests. In addition, the acidic lesion volumes were compared.

RESULTS

MRAPT measurements from the diffusion lesion under the 2 conditions were highly correlated (R² = 0.97) versus MTR_asym measures (R² = 0.58). The pH lesion sizes determined from MRAPT analysis were in good agreement (178 ± 43 mm³ vs. 186 ± 55 mm³ for B₁ of 0.75 and 1.5 µT, respectively).

CONCLUSIONS

The study demonstrated that MRAPT analysis could be generalized to moderately different RF amplitudes, providing a more consistent depiction of acidic lesions than the MTR_asym analysis.

Cost-Effectiveness of Endovascular Thrombectomy in Childhood Stroke: An Analysis of the Save ChildS Study

Background and Purpose

The Save ChildS Study demonstrated that endovascular thrombectomy (EVT) is a safe treatment option for pediatric stroke patients with large vessel occlusions (LVOs) with high recanalization rates. Our aim was to determine the long-term cost, health consequences and cost-effectiveness of EVT in this patient population.

Methods

In this retrospective study, a decision-analytic Markov model estimated lifetime costs and quality-adjusted life years (QALYs). Early outcome parameters were based on the entire Save ChildS Study to model the EVT group. As no randomized data exist, the Save ChildS patient subgroup with unsuccessful recanalization was used to model the standard of care group. For modeling of lifetime estimates, pediatric and adult input parameters were obtained from the current literature. The analysis was conducted in a United States setting applying healthcare and societal perspectives. Probabilistic sensitivity analyses were performed. The willingness-to-pay threshold was set to $100,000 per QALY.

Results

The model results yielded EVT as the dominant (cost-effective as well as cost-saving) strategy for pediatric stroke patients. The incremental effectiveness for the average age of 11.3 years at first stroke in the Save ChildS Study was determined as an additional 4.02 lifetime QALYs, with lifetime cost-savings that amounted to $169,982 from a healthcare perspective and $254,110 when applying a societal perspective. Acceptability rates for EVT were 96.60% and 96.66% for the healthcare and societal perspectives.

Conclusions

EVT for pediatric stroke patients with LVOs resulted in added QALY and reduced lifetime costs. Based on the available data in the Save ChildS Study, EVT is very likely to be a cost-effective treatment strategy for childhood stroke.

Clinical Relevance of Computed Tomography Perfusion-Estimated Infarct Volume in Acute Ischemic Stroke Patients within the 6-h Therapeutic Time Window

INTRODUCTION

Although the estimated infarct volume on baseline computed tomography perfusion (CTP) can identify patients who are likely to benefit from endovascular thrombectomy (EVT) in late time window strokes, the role of CTP imaging in early time windows has not been established. We assessed the clinical impact of CTP-estimated infarct volume on long-term prognosis after EVT, particularly in patients with early time window stroke.

METHODS

We retrospectively reviewed patients who underwent pretreatment CTP and EVT for large vessel occlusion in the anterior circulation within 6 h after symptom onset between March 2014 and February 2019. The infarct volume at baseline CTP was estimated using commercially available software (RAPID, iSchemaView, Menlo Park, CA, USA) with a cerebral blood flow threshold <30% of the normal brain. Risk factors for poor outcome after EVT were evaluated, and a receiver operating characteristic (ROC) curve analysis was used to identify CTP-estimated infarct volumes that optimally predicted the development of symptomatic intracranial hemorrhage (sICH) and poor outcomes (modified Rankin Scale [mRS] 3-6) at 90 days.

RESULTS

Of 120 patients, successful recanalization was achieved in 89 (74.2%) patients, while 61 (50.8%) showed poor outcomes at 90 days. Among 89 patients with successful recanalization after EVT, age, diabetes, clinical stroke severity, CTP-estimated infarct volume, and sICH development were independently associated with 90-day clinical outcomes. ROC analysis identified infarct volumes of ≥88.5 mL and ≥74 mL as the optimal thresholds for predicting poor outcome and development of sICH, respectively. Patients with large infarct volumes showed poorer outcomes (odds ratio [OR], 7.704; 95% confidence interval [CI], 1.528-38.839) and higher rates of sICH development (OR, 10.857; 95% CI, 1.835-64.235). Among patients with large infarction volumes (≥88.5 mL), the 90-day mRS demonstrated a shift toward better outcomes in patients with successful recanalization.

CONCLUSION

Larger initial infarct volumes are significantly associated with worse clinical outcomes in patients who underwent EVT because of early time window stroke. Furthermore, our study of 6-h data demonstrated that an initial infarction of more than a certain volume might be an independent risk factor for sICH development and poor outcomes even in patients with successful recanalization. However, we still observed benefits of EVT in patients with large ischemic cores. The CTP-estimated infarct volume might be an important prognostic factor after EVT rather than a biomarker predicting treatment effectiveness.

The Benefit of Thrombectomy in Patients With Low ASPECTS Is a Matter of Shades of Gray—What Current Trials May Have Missed

Randomized trials supporting the benefit of endovascular treatment in acute ischemic stroke patients with a large early infarction are not yet available. Few retrospective studies exist that suggest a potential positive treatment effect on functional outcome, as well as procedural safety. However, potential benefit or harm of MT in patients with low initial ASPECTS is still a subject of current debate, and in particular, how to select these patients for treatment. The purpose of this pilot study was to evaluate how early tissue water uptake in acute ischemic brain might determine lesion fate and functional outcome in low ASPECTS patients undergoing MT. We observed that the degree of early water uptake measured by quantitative NWU was significantly associated with functional outcome in low ASPECTS patients, yielding a higher diagnostic power compared to other parameters such as ASPECTS, age, or NIHSS. No conclusive evidence of a beneficial effect of successful reperfusion was observed in patients with low ASPECTS and high NWU, which highlights the potential of NWU as a tool to specify patient selection.

Venous outflow profiles are associated with early edema progression in ischemic stroke

BACKGROUND

In patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO), development of extensive early ischemic brain edema is associated with poor functional outcomes, despite timely treatment. Robust cortical venous outflow (VO) profiles correlate with favorable tissue perfusion. We hypothesized that favorable VO profiles (VO+) correlate with a reduced early edema progression rate (EPR) and good functional outcomes.

METHODS

Multicenter, retrospective analysis to investigate AIS-LVO patients treated by mechanical thrombectomy between May 2013 and December 2020. Baseline computed tomography angiography (CTA) was used to determine VO using the cortical vein opacification score (COVES); VO+ was defined as COVES ⩾ 3 and unfavorable as COVES ⩽ 2. EPR was determined as the ratio of net water uptake (NWU) on baseline non-contrast CT and time from symptom onset to admission imaging. Multivariable regression analysis was performed to assess primary (EPR) and secondary outcome (good functional outcomes defined as 0-2 points on the modified Rankin scale).

RESULTS

A total of 728 patients were included. Primary outcome analysis showed VO+ (β: -0.03, SE: 0.009, p = 0.002), lower presentation National Institutes of Health Stroke Scale (NIHSS; β: 0.002, SE: 0.001, p = 0.002), and decreased time from onset to admission imaging (β: -0.00002, SE: 0.00004, p < 0.001) were independently associated with reduced EPR. VO+ also predicted good functional outcomes (odds ratio (OR): 5.07, 95% CI: 2.839-9.039, p < 0.001), while controlling for presentation NIHSS, time from onset to imaging, general vessel reperfusion, baseline Alberta Stroke Program Early CT Score, infarct core volume, EPR, and favorable arterial collaterals.

CONCLUSIONS

Favorable VO profiles were associated with slower infarct edema progression and good long-term functional outcomes as well as better neurological status and ischemic brain alterations at admission.

Microvascular Dysfunction in Blood-Brain Barrier Disruption and Hypoperfusion Within the Infarct Posttreatment Are Associated With Cerebral Edema

BACKGROUND AND PURPOSE

Factors contributing to cerebral edema in the post-hyperacute period of ischemic stroke (first 24-72 hours) are poorly understood. Blood-brain barrier (BBB) disruption and postischemic hyperperfusion reflect microvascular dysfunction and are associated with hemorrhagic transformation. We investigated the relationships between BBB integrity, cerebral blood flow, and space-occupying cerebral edema in patients who received acute reperfusion therapy.

METHODS

We performed a pooled analysis of patients treated for anterior circulation large vessel occlusion in the EXTEND-IA TNK and EXTEND-IA TNK part 2 trials who had MRI with dynamic susceptibility contrast-enhanced perfusion-weighted imaging 24 hours after treatment. We investigated the associations between BBB disruption and cerebral blood flow within the infarct with cerebral edema assessed using 2 metrics: first midline shift (MLS) trichotomized as an ordinal scale of negligible (<1 mm), mild (≥1 to <5 mm), or severe (≥5 mm), and second relative hemispheric volume (rHV), defined as the ratio of the 3-dimensional volume of the ischemic hemisphere relative to the contralateral hemisphere.

RESULTS

Of 238 patients analyzed, 133 (55.9%) had negligible, 93 (39.1%) mild, and 12 (5.0%) severe MLS at 24 hours. The associated median rHV was 1.01 (IQR, 1.00-1.028), 1.03 (IQR, 1.01-1.077), and 1.15 (IQR, 1.08-1.22), respectively. MLS and rHV were associated with poor functional outcome at 90 days (P<0.002). Increased BBB permeability was independently associated with more edema after adjusting for age, occlusion location, reperfusion, parenchymal hematoma, and thrombolytic agent used (MLS cOR, 1.12 [95% CI, 1.03-1.20], P=0.005; rHV β, 0.39 [95% CI, 0.24-0.55], P<0.0001), as was reduced cerebral blood flow (MLS cOR, 0.25 [95% CI, 0.10-0.58], P=0.001; rHV β, -2.95 [95% CI, -4.61 to -11.29], P=0.0006). In subgroup analysis of patients with successful reperfusion (extended Treatment in Cerebral Ischemia 2b-3, n=200), reduced cerebral blood flow remained significantly associated with edema (MLS cOR, 0.37 [95% CI, 0.14-0.98], P=0.045; rHV β, -2.59 [95% CI, -4.32 to -0.86], P=0.004).

CONCLUSIONS

BBB disruption and persistent hypoperfusion in the infarct after reperfusion treatment is associated with space-occupying cerebral edema. Further studies evaluating microvascular dysfunction during the post-hyperacute period as biomarkers of poststroke edema and potential therapeutic targets are warranted.