Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

No-reflow after recanalization in ischemic stroke: From pathomechanisms to therapeutic strategies

Endovascular reperfusion therapy is the primary strategy for acute ischemic stroke. No-reflow is a common phenomenon, which is defined as the failure of microcirculatory reperfusion despite clot removal by thrombolysis or mechanical embolization. It has been reported that up to 25% of ischemic strokes suffer from no-reflow, which strongly contributes to an increased risk of poor clinical outcomes. No-reflow is associated with functional and structural alterations of cerebrovascular microcirculation, and the injury to the microcirculation seriously hinders the neural functional recovery following macrovascular reperfusion. Accumulated evidence indicates that pathology of no-reflow is linked to adhesion, aggregation, and rolling of blood components along the endothelium, capillary stagnation with neutrophils, astrocytes end-feet, and endothelial cell edema, pericyte contraction, and vasoconstriction. Prevention or treatment strategies aim to alleviate or reverse these pathological changes, including targeted therapies such as cilostazol, adhesion molecule blocking antibodies, peroxisome proliferator-activated receptors (PPARs) activator, adenosine, pericyte regulators, as well as adjunctive therapies, such as extracorporeal counterpulsation, ischemic preconditioning, and alternative or complementary therapies. Herein, we provide an overview of pathomechanisms, predictive factors, diagnosis, and intervention strategies for no-reflow, and attempt to convey a new perspective on the clinical management of no-reflow post-ischemic stroke.

Futile recanalization is associated with increased risk of post-stroke epilepsy

BACKGROUND

Endovascular treatment (EVT) is the standard of care of ischaemic stroke due to occlusion of large vessels. Although EVT can significantly improve short- and long-term outcomes, functional dependence can persist despite the achievement of a successful recanalization. The evidence about the predictors of post-stroke epilepsy (PSE) in patients with stroke treated by EVT is limited. We aimed to evaluate the relationship between futile recanalization and the risk of PSE.

METHODS

We retrospectively identified consecutive adults with first-ever ischaemic stroke of anterior circulation who were treated with EVT. Futile recanalization was defined as poor 3-month functional status (modified Rankin scale score ≥ 3) despite complete or near-complete recanalization. Study outcome was the occurrence of PSE during the follow-up.

RESULTS

The study included 327 patients with anterior circulation ischaemic stroke treated with EVT. Futile recanalization occurred in 116 (35.5%) patients and 26 (8.0%) developed PSE during a median follow-up of 35 [interquartile range, 22.7-55.2] months. Futile recanalization was more common among patients who developed PSE compared to those who did not (76.9% versus 31.9%; p < 0.001). Futile recanalization [hazard ratio (HR) = 5.63, 95% confidence interval (CI): 1.88-16.84; p = 0.002], large artery atherosclerosis (HR = 3.48, 95% CI: 1.44-8.40; p = 0.006), cortical involvement (HR = 15.51, 95% CI: 2.06-116.98; p = 0.008), and acute symptomatic status epilepticus (HR = 14.40, 95% CI: 2.80-73.98; p = 0.001) increased the risk of PSE.

CONCLUSIONS

Futile recanalization after EVT is associated with increased risk of PSE in patients with ischaemic stroke due to occlusion of large vessel of the anterior circulation.

Proteomic analysis of jugular venous blood in acute large vessel occlusion stroke with futile recanalization

Futile recanalization (FR) after endovascular treatment (EVT) remains a significant challenge for acute ischemic stroke (AIS) with large vessel occlusion (LVO). The pathogenesis of FR has not been well elucidated. We prospectively enrolled anterior circulation LVO-AIS patients who achieved successful recanalization after EVT. The jugular venous blood ipsilateral to stroke was collected before and immediately after recanalization. Plasma proteomic analysis based on liquid chromatography-mass spectrometry was performed using data-independent acquisition method. Differentially expressed proteins (DEPs) among patients with or without FR in the whole or propensity score matching (PSM) cohorts were screened according to the absolute value of fold change ≥1.5 and P value <0.05. We identified 104 and 34 DEPs between patients with or without FR in the whole cohort and PSM cohort, respectively. Bioinformatic analysis indicated that the identified proteins were primarily related to specific biological processes including immune response, complement activation, oxidative stress, lipid metabolism, protein ubiquitylation as well as autophagy, suggesting that these may be mechanisms in FR pathogenesis. Collectively, we discovered proteins that may be potential research targets for FR. The combination of proteomic and bioinformatic analysis could provide a better understanding of the pathogenesis of FR in a comprehensive manner.

Influencing factors of futile recanalization after endovascular intervention in patients with acute basilar artery occlusion

OBJECTIVES

To explore the influence factors for futile recanalization following endovascular treatment (EVT) in patients with acute basilar artery occlusion (BAO).

METHODS

Clinical data of patients with acute BAO, who underwent endovascular treatment within 24 h of onset from January 2017 to November 2022, were retrospectively analyzed. The futile recanalization was defined as modified thrombolysis in cerebral infarction (mTICI) grade ≥2b or 3 after successful reperfusion, but the modified Rankin Scale score >2 at 3 months after EVT. Binary logistic regression model was used to analyze the influencing factors of futile recanalization.

RESULTS

A total of 471 patients with a median age of 68 (57, 74) years were included and 68.9% were males, among whom 298 (63.27%) experienced futile recanalization. Multivariate analysis revealed that concomitant atrial fibrillation (OR=0.456, 95%CI: 0.282-0.737, P<0.01), bridging thrombolysis (OR=0.640, 95%CI: 0.416-0.985, P<0.05), achieving mTICI grade 3 (OR=0.554, 95%CI: 0.334-0.918, P<0.05), arterial occlusive lesion (AOL) grade 3 (OR=0.521, 95%CI: 0.326-0.834, P<0.01), and early postoperative statin therapy (OR=0.509, 95%CI: 0.273-0.948, P<0.05) were protective factors for futile recanalization after EVT in acute BAO patients. High baseline National Institutes of Health Stroke Scale (NIHSS) score (OR=1.068, 95%CI: 1.049-1.087, P<0.01), coexisting hypertension (OR=1.571, 95%CI: 1.017-2.427, P<0.05), multiple retrieval attempts (OR=1.237, 95%CI: 1.029-1.488, P<0.05) and postoperative hemorrhagic transformation (OR=8.497, 95%CI: 2.879-25.076, P<0.01) were risk factors. For trial of ORG 10172 in acute stroke treatment (TOAST) classification, cardiogenic embolism (OR=0.321, 95%CI: 0.193-0.534, P<0.01) and other types (OR=0.499, 95%CI: 0.260-0.961, P<0.05) were related to lower incidence of futile recanalization.

CONCLUSIONS

The incidence of futile recanalization after EVT in patients with acute BAO is high. Bridging venous thrombolysis before operation and an early postoperative statin therapy may reduce the incidence of futile recanalization.

Evolution pattern estimated by computed tomography perfusion post-thrombectomy predicts outcome in acute ischemic stroke

OBJECTIVES

Computed tomography perfusion (CTP) and computed tomography angiography (CTA) have been recommended to select acute ischemic stroke (AIS) patients for endovascular thrombectomy (EVT) but are not widely used for post-treatment evaluation. We aimed to observe abnormalities in CTP and CTA before and after EVT and evaluate post-EVT CTP and CTA as potential tools for improving clinical outcome prediction.

METHODS

Patients with AIS who underwent EVT and received CTP and CTA before and after EVT were retrospectively evaluated. The ischemic core was defined as the volume of relative cerebral blood flow <30% and hypoperfusion as the volume of Tmax >6 s. A reduction in hypoperfusion volume >90% between baseline and post-EVT CTP was defined as tissue optimal reperfusion (TOR). The 90-day modified Rankin scale was used to evaluate the clinical outcome.

RESULTS

Eighty-three patients were included. Patients with an absent ischemic core or with TOR after EVT had a higher rate of modified Thrombolysis in Cerebral Ischemia score 2c-3 and recanalization of post-treatment vessel condition based on follow-up CTA. Multivariable logistic regression revealed that the baseline ischemic core volume (OR:0.934, p=0.009), TOR (OR:8.322, p=0.029) and immediate NIHSS score after EVT (OR:0.761, p=0.012) were factors significantly associated with good clinical outcome. Combining baseline ischemic core volume and TOR with immediate NIHSS score after EVT showed greatest performance for good outcome prediction after EVT(AUC=0.921).

CONCLUSIONS

The addition of pretreatment and post-treatment CTP information to purely clinical NIHSS scores might help to improve the efficacy for good outcome prediction after EVT.

Long term for patients with futile endovascular reperfusion after stroke

AIMS

With the progress of thrombectomy technology, the vascular recanalization rate of patients with stroke has been continuously improved, but the proportion of futile recanalization (FR) is still quite a few. The long-term prognosis and survival of patients with FR and its influencing factors remain unclear.

METHODS

Consecutive patients who received endovascular treatment (EVT) for ischemic stroke were enrolled between 2013 and 2021 from a single-center prospectively registry study. We evaluated the long-term outcome of these patients by Kaplan-Meier survival analysis, and the multivariable logistic regression curve was performed to analyze influencing factors.

RESULTS

Among 458 patients with FR, 56.4% of patients survived at 1 year, and 50.4% at 2 years. In the multivariate regression analysis, age, premorbid modified Rankin Scale (mRS), National Institutes of Health Stroke Scale (NIHSS), posterior circulation infarct, general anesthesia, symptomatic intracerebral hemorrhage (sICH), and decompressive craniectomy were found to be related to unfavorable outcomes in long-term. Age, premorbid mRS, NIHSS, general anesthesia, and sICH were predictors of long-term mortality.

CONCLUSIONS

Futile recanalization accounts for a large proportion of stroke patients after thrombectomy. This study on the long-term prognosis of such patients is beneficial to the formulation of treatment plans and the prediction of therapeutic effects.

Prediction of futile recanalisation after endovascular treatment in acute ischaemic stroke: development and validation of a hybrid machine learning model

BACKGROUND

Identification of futile recanalisation following endovascular therapy (EVT) in patients with acute ischaemic stroke is both crucial and challenging. Here, we present a novel risk stratification system based on hybrid machine learning method for predicting futile recanalisation.

METHODS

Hybrid machine learning models were developed to address six clinical scenarios within the EVT and perioperative management workflow. These models were trained on a prospective database using hybrid feature selection technique to predict futile recanalisation following EVT. The optimal model was validated and compared with existing models and scoring systems in a multicentre prospective cohort to develop a hybrid machine learning-based risk stratification system for futile recanalisation prediction.

RESULTS

Using a hybrid feature selection approach, we trained and tested multiple classifiers on two independent patient cohorts (n=1122) to develop a hybrid machine learning-based prediction model. The model demonstrated superior discriminative ability compared with other models and scoring systems (area under the curve=0.80, 95% CI 0.73 to 0.87) and was transformed into a web application (RESCUE-FR Index) that provides a risk stratification system for individual prediction (accessible online at fr-index.biomind.cn/RESCUE-FR/).

CONCLUSIONS

The proposed hybrid machine learning approach could be used as an individualised risk prediction model to facilitate adherence to clinical practice guidelines and shared decision-making for optimal candidate selection and prognosis assessment in patients undergoing EVT.

Risk Factors, Pathophysiologic Mechanisms, and Potential Treatment Strategies of Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

Endovascular therapy is the first-line treatment for acute ischemic stroke. However, studies have shown that, even with the timely opening of occluded blood vessels, nearly half of all patients treated with endovascular therapy for acute ischemic stroke still have poor functional recovery, a phenomenon called "futile recanalization.". The pathophysiology of futile recanalization is complex and may include tissue no-reflow (microcirculation reperfusion failure despite recanalization of the occluded large artery), early arterial reocclusion (reocclusion of the recanalized artery 24-48 hours post endovascular therapy), poor collateral circulation, hemorrhagic transformation (cerebral bleeding following primary ischemic stroke), impaired cerebrovascular autoregulation, and large hypoperfusion volume. Therapeutic strategies targeting these mechanisms have been attempted in preclinical research; however, translation to the bedside remains to be explored. This review summarizes the risk factors, pathophysiological mechanisms, and targeted therapy strategies of futile recanalization, focusing on the mechanisms and targeted therapy strategies of no-reflow to deepen the understanding of this phenomenon and provide new translational research ideas and potential intervention targets for improving the efficacy of endovascular therapy for acute ischemic stroke.

Mechanical thrombectomy in low Alberta stroke program early CT score (ASPECTS) in hyperacute stroke-a systematic review and meta-analysis

OBJECTIVE

Major randomized controlled trials of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) failed to include a substantial number of patients presenting with low baseline Alberta Stroke Program Early CT Score (ASPECTS:0-5). Patients experiencing hyperacute strokes (last known well ≤ 6 h) can potentially benefit most from MT. We conducted a systematic review and meta-analysis to report presentation severity and radiographic and clinical outcomes for hyperacute stroke patients presenting with low-ASPECTS.

METHODS

Our comprehensive literature search of PubMed, Embase, and Cochrane databases up to August 31, 2022 included articles reporting patients presenting hyperacutely who underwent MT for anterior circulation large vessel occlusion AIS with an ASPECTS ≤ 5 on baseline imaging. Pooled averages were calculated for age and presenting National Institutes of Health Stroke Scale (NIHSS). Fixed- and random-effects meta-analyses for weighted estimation of overall rates were performed. Forest plots were generated for proportions and estimated overall outcome rates.

RESULTS

18 studies (1958 patients) were included (mean age = 64.1 years; presenting NIHSS = 18.4). Final modified thrombolysis in cerebral infarction 2b-3 grade was achieved in 76.4%, with symptomatic intracranial hemorrhage in 12.1%. Good (modified Rankin Scale [mRS] 0-2) and ambulatory (mRS 0-3) 3-month outcomes were achieved by 27.4 and 46.7%, respectively; 90-day mortality was 26.4%.

CONCLUSION

MT in low-ASPECTS hyperacute stroke patients may result in ambulatory clinical outcomes with acceptable hemorrhage risk. Recanalization rates achieved were similar to those in patients presenting with ASPECTS ≥ 6; this did not fully translate to better clinical outcomes.

ADVANCES IN KNOWLEDGE

MT should be considered for hyperacute strokes with low presenting ASPECTS.

Quercetin improves cerebral ischemia/reperfusion injury by promoting microglia/macrophages M2 polarization via regulating PI3K/Akt/NF-κB signaling pathway

The modulation of microglial polarization from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype shows promise as a therapeutic strategy for ischemic stroke. Quercetin, a natural flavonoid abundant in various plants, possesses anti-inflammatory, anti-apoptotic, and antioxidant properties. Nevertheless, its effect and underlying mechanism on microglia/macrophages M1/M2 polarization in the treatment of cerebral ischemia/reperfusion injury (CI/RI) remain poorly explored. In the current study, we observed that quercetin ameliorated neurological deficits, reduced infarct volume, decreased the number of M1 microglia/macrophages (CD16/32+/Iba1+), and enhanced the number of M2 microglia/macrophages (CD206+/Iba1+) after establishing the CI/RI model in rats. Subsequent in vivo and in vitro experiments indicated that quercetin downregulated M1 markers (CD86, iNOS, TNF-α, IL-1β, and IL-6) and upregulated M2 markers (CD206, Arg-1, IL-10, and TGF-β). Network pharmacology analysis and molecular docking revealed that the PI3K/Akt/NF-κB signaling pathway emerged as the core pathway. Western blot confirmed that quercetin upregulated the phosphorylation of PI3K and Akt, while alleviating the phosphorylation of IκBα and NF-κB both in vivo and in vitro. However, the PI3K inhibitor LY294002 reversed the effects of quercetin on M2 polarization and the expression of key proteins in the PI3K/Akt/NF-κB pathway in primary microglia after oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. Collectively, our findings demonstrate that quercetin facilitates microglia/macrophages M2 polarization by modulating the PI3K/Akt/NF-κB signaling pathway in the treatment of CI/RI. These findings provide novel insights into the therapeutic mechanisms of quercetin in ischemic stroke.

Mechanical thrombectomy in young patients with large vessel occlusion-related ischemic stroke: Data from the Italian Registry of Endovascular Treatment in Acute Stroke

BACKGROUND AND PURPOSE

The weight of outcome predictors in acute ischemic stroke (AIS) patients older than 60 years is not necessarily mirrored in the younger population, posing the question of whether outcome determinants specific for the latter might vary. Very few data are available on predictors of outcome in young AIS patients receiving endovascular treatment (EVT).

METHODS

We analyzed data for patients aged between 16 and 55 years from the Italian Registry of Endovascular Treatment in Acute Stroke. We divided our population into patients <45 years old and patients aged between 45 and 55 years. After testing the differences between groups in terms of 90-day modified Rankin Scale (mRS) 0-2, mortality, and symptomatic intracranial hemorrhage, we looked for predictors of poor outcome (mRS 3-6), death, and symptomatic intracerebral hemorrhage in the two groups.

RESULTS

A total of 438 patients younger than 45 years and 817 aged 45-55 years were included; 284 (34.8%) patients aged 45-55 years and 112 (25.6%) patients younger than 45 years old showed poor 90-day functional outcome (p = 0.001). Predictors of poor outcome in the older group were baseline National Institutes of Health Stroke Scale (NIHSS; p < 0.001), diabetes (p = 0.027), poor collateral status (p = 0.036), and groin puncture-to-recanalization time (p = 0.010), whereas Thrombolysis in Cerebral Infarction (TICI) 2b-3 had an inverse association (p < 0.001). Predictors of poor outcome in patients younger than 45 years were baseline NIHSS (p < 0.001) and groin puncture-to-recanalization time (p = 0.015), whereas an inverse association was found for baseline Alberta Stroke Program Early CT Score (p = 0.010) and TICI 2b-3 (p < 0.001).

CONCLUSIONS

Approximately one third of young adults treated with EVT do not reach a good functional outcome. Fast and successful recanalization, rather than common risk factors, has a major role in determining clinical outcome.

No-reflow phenomenon in acute ischemic stroke: an angiographic evaluation

BACKGROUND

Futile recanalization (FR) is de fined as a poor 90-day outcome or lack of neurological improvement at 24 h despite successful recanalization in acute ischemic stroke (AIS) with large vessel occlusion (LVO) treated by mechanical throbectomy (MT). The No-reflow phenomenon (NRP) could be a possible cause of FR, but its evidence in AIS patients is scarce.

METHODS

We retrospectively analyzed 185 digital subtraction angiographies (DSA) of AIS patients with anterior circulation LVO after endovascular treatment. To better define NRP, we designed a score called the modified capillary index score (mCIS). The score is obtained by dividing the middle cerebral artery territory in three segments. For each segment, we gave 2 points if the capillary blush was present without any delay, 1 if delayed, and 0 if absent. The primary endpoint was to use mCIS to identify NRP on post-interventional DSA and to test whether this marker may predict FR and failure of early neurological improvement (fENI). The secondary endpoint was to search for a correlation between NRP, lesion volume, and hemorrhagic transformation. We used the ROC curve to define mCIS ≤ 3 as the cut-off and marker of NRP.

RESULTS

NRP was present in 35.1% of patients. NRP predicted fENI at 24 h (aOR 2.825, 95% CI 1.265-6.308, P = 0.011) and at 7 days (aOR 2.191, 95% CI 1.008-4.762, P = 0.048), but not 90-day FR. Moreover, NRP predicted hemorrhagic transformation (aOR 2.444, 95% CI 1.266-4.717, P = 0.008).

CONCLUSIONS

The modified capillary index score (mCIS) seems useful in identifying NRP in AIS. In addition, mCIS was able to predict NRP that correlated with early clinical outcome and hemorrhagic transformation of the ischemic lesion. An external validation of the score is warranted.

URB597 exerts neuroprotective effects against transient brain ischemia injury in mice by regulating autophagic flux and necroptosis

Ischemic stroke is a leading cause of death and disability, and medical treatments for ischemic stroke are very limited. URB597 is a potent and selective inhibitor of fatty acid amide hydrolase (FAAH). However, the effect of URB597 on ischemic stroke and the underlying molecular mechanisms remain little known. In this study, focal cerebral ischemia was induced by transient middle cerebral artery occlusion in mice. Our results showed that URB597 dose-dependently improved neurological function and reduced brain infarct volume and brain edema 24 h after brain ischemia. The most effective dose was 1 mg/kg and the therapeutic time window was within 3 h after ischemic stroke. To further investigate the underlying mechanism, necroptosis and autophagy flux were detected by Western blot and/or immunofluorescence staining with or without chloroquine, an autophagic flux inhibitor. Our results showed that URB597 promoted autophagic flux and reduced neuronal necroptosis after brain ischemia and these effects could be abolished by chloroquine. In addition, we found that peroxisome proliferator-activated receptor α (PPARα) antagonist GW6471 partly abolished the effect of URB597 against brain ischemia and URB597 upregulated the expressions of PPARα. In conclusion, URB597 exerts a neuroprotective effect in a dose- and time-dependent manner, and this effect may be related to its restoration of autophagic flux and inhibition of neuronal necroptosis. PPARα is involved in the neuroprotective effect of URB597. This study provides novel evidence that URB597 may be a promising agent for the clinical treatment of ischemic stroke.

miR-188-5p silencing improves cerebral ischemia/reperfusion injury by targeting Lin28a

This report aimed to explore whether miR-188-5p regulated the pathological regulatory network of cerebral ischemia/reperfusion (I/R) injury. We simulated the cerebral I/R injury model with MACO/R and OGD/R treatments. Neuronal viability and apoptosis were assessed. The contents of miR-188-5p and Lin 28a were evaluated. The abundances of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) and pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) were measured. The interaction of miR-188-5p and Lin28a was confirmed. Lin28a silencing was supplemented to determine the delicate regulation of miR-188-5p. We revealed that miR-188-5p was upregulated and Lin28a was downregulated in I/R rats and OGD/R-induced cells. miR-188-5p silencing remarkably reduced the cerebral infarction volume, neurobehavioral score, brain edema, and Evans blue leakage. miR-188-5p silencing enhanced neuronal viability and alleviated apoptosis. The abundance of Bax and cleaved caspase-3 was reduced by miR-188-5p silencing, while Bcl-2 was augmented. miR-188-5p silencing impeded the contents of TNF-α, IL-1β, and IL-6. miR-188-5p interacted with Lin28a and negatively regulated its expression. Interestingly, extra Lin28a silencing reversed apoptosis and the content of inflammatory cytokines. Our studies confirmed that miR-188-5p silencing alleviated neuronal apoptosis and inflammation by mediating the expression of Lin28a. The crosstalk of miR-188-5p and Lin28a offered a different direction for ischemic stroke therapy.

Persistent perfusion abnormalities at day 1 correspond to different clinical trajectories after stroke

BACKGROUND

Perfusion abnormalities after thrombolysis are frequent within and surrounding ischemic lesions, but their relative frequency is not well known.

OBJECTIVE

To describe the different patterns of perfusion abnormalities observed at 24 hours and compare the characteristics of the patients according to their perfusion pattern.

METHODS

From our thrombolysis registry, we included 226 consecutive patients with an available arterial spin labeling (ASL) perfusion sequence at day 1. We performed a blinded assessment of the perfusion status (hypoperfusion-h, hyperperfusion-H, or normal-N) in the ischemic lesion and in the surrounding tissue. We compared the time course of clinical recovery, the rate of arterial recanalization, and hemorrhagic transformations in the different perfusion profiles.

RESULTS

We identified seven different perfusion profiles at day 1. Four of these (h/h, h/H, H/H, and H/N) represented the majority of the population (84.1%). The H/H profile was the most frequent (34.5%) and associated with 3-month good outcome (modified Rankin Scale (mRS): 63.5%). Patients with persistent hypoperfusion within and outside the lesion (h/h, 12.4%) exhibited worse outcomes after treatment (mRS score 0-2: 23.8%) than other patients, were less frequently recanalized (40.7%), and had more parenchymal hematoma (17.8%). The h/H profile had an intermediate clinical trajectory between the h/h profile and the hyperperfused profiles.

CONCLUSION

ASL hypoperfusion within the infarct and the surrounding tissue was associated with poor outcome. A more comprehensive view of the mechanisms in the hypoperfused surrounding tissue could help to design new therapeutic approaches during and after reperfusion therapies.

A DWI-based radiomics-clinical machine learning model to preoperatively predict the futile recanalization after endovascular treatment of acute basilar artery occlusion patients

OBJECTIVE

To develop an effective machine learning model to preoperatively predict the occurrence of futile recanalization (FR) of acute basilar artery occlusion (ABAO) patients with endovascular treatment (EVT).

MATERIALS AND METHODS

Data from 132 ABAO patients (109 male [82.6 %]; mean age ± standard deviation, 59.1 ± 12.5 years) were randomly divided into the training (n = 106) and test cohort (n = 26) with a ratio of 8:2. FR is defined as a poor outcome [modified Rankin Scale (mRS) 4-6] despite a successful recanalization [modified Thrombolysis in Cerebral Infarction (mTICI) ≥ 2b]. A total of 1130 radiomics features were extracted from diffusion-weighted imaging (DWI) images. The least absolute shrinkage and selection operator (LASSO) regression method was applicated to select features. Support vector machine (SVM) was applicated to construct radiomics and clinical models. Finally, a radiomics-clinical model that combined clinical with radiomics features was developed. The models were evaluated by receiver operating characteristic (ROC) curve and decision curve.

RESULTS

The area under the receiver operating characteristic (ROC) curve (AUC) of the radiomics-clinical model was 0.897 (95 % confidence interval, 0.837-0.958) in the training cohort and 0.935 (0.833-1.000) in the test cohort. The AUC of the radiomics model was 0.887 (0.824-0.951) in the training cohort and 0.840 (0.680-1.000) in the test cohort. The AUC of the clinical model was 0.746 (0.652-0.840) in the training cohort and 0.766 (0.569-0.964) in the test cohort. The AUC of the radiomics-clinical model was significantly larger than the clinical model (p = 0.016). A radiomics-clinical nomogram was developed. The decision curve analysis indicated its clinical usefulness.

CONCLUSION

The DWI-based radiomics-clinical machine learning model achieved satisfactory performance in predicting the FR of ABAO patients preoperatively.

A retrospect and outlook on the neuroprotective effects of anesthetics in the era of endovascular therapy

Studies on the neuroprotective effects of anesthetics were carried out more than half a century ago. Subsequently, many cell and animal experiments attempted to verify the findings. However, in clinical trials, the neuroprotective effects of anesthetics were not observed. These contradictory results suggest a mismatch between basic research and clinical trials. The Stroke Therapy Academic Industry Roundtable X (STAIR) proposed that the emergence of endovascular thrombectomy (EVT) would provide a proper platform to verify the neuroprotective effects of anesthetics because the haemodynamics of patients undergoing EVT is very close to the ischaemia–reperfusion model in basic research. With the widespread use of EVT, it is necessary for us to re-examine the neuroprotective effects of anesthetics to guide the use of anesthetics during EVT because the choice of anesthesia is still based on team experience without definite guidelines. In this paper, we describe the research status of anesthesia in EVT and summarize the neuroprotective mechanisms of some anesthetics. Then, we focus on the contradictory results between clinical trials and basic research and discuss the causes. Finally, we provide an outlook on the neuroprotective effects of anesthetics in the era of endovascular therapy.

Clinically Ineffective Reperfusion After Endovascular Therapy in Acute Ischemic Stroke

Endovascular treatment is a highly effective therapy for acute ischemic stroke due to large vessel occlusion. However, in clinical practice, nearly half of the patients do not have favorable outcomes despite successful recanalization of the occluded artery. This unfavorable outcome can be defined as having clinically ineffective reperfusion. The objective of the review is to describe clinically ineffective reperfusion after endovascular therapy and its underlying risk factors and mechanisms, including initial tissue damage, cerebral edema, the no-reflow phenomenon, reperfusion injury, procedural features, and variations in postprocedural management. Further research is needed to more accurately identify patients at a high risk of clinically ineffective reperfusion after endovascular therapy and to improve individualized periprocedural management strategies, to increase the chance of achieving favorable clinical outcomes.

Effects of prior antiplatelet use on futile reperfusion in patients with acute ischemic stroke receiving endovascular treatment

Introduction:

We evaluated the effects of prior antiplatelet use (APU) on futile reperfusion (FR) after endovascular treatment (EVT) in acute ischemic stroke.

Material and methods:

We consecutively collected data of 9369 patients with acute ischemic stroke from four university-affiliated multicenter registry databases over 92 months. We enrolled 528 patients with acute stroke receiving EVT. Among them, we defined FR in subjects as a 3-month modified Rankin Scale score of >2 despite successful reperfusion after EVT. We classified patients into two groups: prior APU and no prior APU. We used propensity score matching (PSM) to overcome the imbalance in multiple covariates between the two groups. After PSM, we compared the baseline characteristics between the two groups and performed multivariate analysis to determine whether prior APU affected FR and other stroke outcomes.

Results:

The overall FR rate in the present study was 54.2%. In the PSM cohort, the FR was lower in the prior APU group than that in the no prior APU group (66.2% vs 41.5%, p < 0.001). In the multivariate analysis using the PSM cohort, prior APU significantly reduced the risk of FR (odds ratio (OR), 0.32; 95% confidence interval (CI), 0.18–0.55; p = 0.001) and stroke progression (OR, 0.38; 95% CI, 0.15–0.93; p = 0.03). Prior APU was not associated with symptomatic hemorrhagic transformation in this study.

Conclusion:

Prior APU potentially reduced FR and stroke progression. Further, prior APU was not associated with symptomatic hemorrhagic transformation in patients receiving EVT. APU pretreatment can be a modifiable predictor of FR in clinical practice.

Elucidating the Role of Baseline Leukoaraiosis on Forecasting Clinical Outcome of Acute Ischemic Stroke Patients Undergoing Reperfusion Therapy

Stroke stands as a major cause of death and disability with increasing prevalence. The absence of clinical improvement after either intravenous thrombolysis (IVT) or mechanical thrombectomy (MT) represents a frequent concern in the setting of acute ischemic stroke (AIS). In an attempt to optimize overall stroke management, it is clinically valuable to provide important insight into functional outcomes after reperfusion therapy among patients presenting with AIS. The aim of the present review is to explore the predictive value of leukoaraiosis (LA) in terms of clinical response to revascularization poststroke. A literature research of two databases (MEDLINE and Scopus) was conducted in order to trace all relevant studies published between 1 January 2012 and 1 November 2022 that focused on the potential utility of LA severity regarding reperfusion status and clinical outcome after revascularization. A total of 37 articles have been traced and included in this review. LA burden assessment is indicative of functional outcome post-intervention and may be associated with hemorrhagic events' incidence among stroke individuals. Nevertheless, LA may not solely guide decision-making about treatment strategy poststroke. Overall, the evaluation of LA upon admission seems to have interesting prognostic potential and may substantially enhance individualized stroke care.

Cerebral Small Vessel Disease Burden and Futile Reperfusion after Endovascular Treatment for Patients with Acute Ischemic Stroke

INTRODUCTION

Cerebral small vessel disease (SVD) burden includes increased risk of poor functional outcomes after acute ischemic stroke (AIS). We aimed to investigate the impact of cerebral SVD on 3-month functional outcomes in patients with AIS who received endovascular treatment (EVT) and to determine whether SVD is associated with futile reperfusion (FR).

METHODS

Using a multicenter stroke registry, we analyzed consecutive patients with AIS with either intracranial and/or extracranial anterior circulation large artery occlusion, who were treated with EVT and achieved successful reperfusion (thrombolysis in cerebral infarction grade 2b-3). The cerebral SVD burden was evaluated using baseline brain magnetic resonance imaging using a modified Fazekas score (mFS). The main outcome variable was FR, defined as poor functional outcomes (modified Rankin scale 3-6) at 3 months after stroke, despite successful recanalization. Secondary outcomes included stroke progression/recurrence and any hemorrhagic transformation.

RESULTS

Among 10,890 patients with AIS, 577 (5.3%) received EVT within 12  h of onset, including 354 who met study eligibility criteria. FR was observed in 191 patients (53.5%) and was positively associated with SVD burden. After adjustment for covariates including age, sex, stroke etiology, initial stroke severity, collateral status, Alberta stroke program early CT score, initial serum glucose, systemic blood pressure, and vascular risk factors, mFS grade 3 was significantly associated with FR (odds ratio: 3.93, 95% confidence interval: 1.602-9.619; p = 0.003).

CONCLUSIONS

We demonstrated that cerebral SVD assessed with baseline brain MRI is associated with the futility of successful recanalization after EVT and any hemorrhagic transformation but not with early stroke progression or recurrence. Nevertheless, our findings do not justify withholding EVT in otherwise eligible patients with AIS based on the presence of severe SVD.

Postoperative neutrophil-lymphocyte ratio predicts unfavorable outcome of acute ischemic stroke patients who achieve complete reperfusion after thrombectomy

Purpose

Only approximately half of anterior circulation large vessel occlusion (LVO) patients receiving endovascular treatment (EVT) have a favorable outcome. The aim of this study was to explore the association of dynamic inflammatory markers (i.e., neutrophil to lymphocyte ratios, NLR, measured at different times after EVT) as well as other potential influencing factors with unfavorable outcome among acute ischemic stroke (AIS) patients who achieved complete reperfusion after EVT.

Methods

Patients treated with EVT for LVO between January 2019 to December 2021 were prospectively enrolled. Complete reperfusion was defined as modified thrombolysis in cerebral infarction (mTICI) grade 3. A modified Rankin scale at 90 days (mRS90) of 3-6 was defined as unfavorable outcome (i.e., futile reperfusion). A logistic regression analysis was performed with unfavorable outcome as a dependent variable. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were then used to determine the diagnostic values of NLR and other relevant factors.

Results

170 patients with complete reperfusion (mTICI 3) were included in this study. Unfavorable outcome was observed in 70 (41.2%). Higher NLR within 24h (p=0.017) and at 3-7d (p=0.008) after EVT were an independent risk factors for unfavorable outcome at 3 months. In addition, older age, higher NIHSS scores, poor collaterals, and general anesthesia were independent predictors of unfavorable outcomes. When accounting for NLR, the diagnostic efficiency improved compared to conventional characteristics.

Conclusion

Our findings suggest that advanced age, increased stroke severity, poor collaterals, general anesthesia, and NLR are independent predictors for an unfavorable clinical outcome following complete reperfusion after EVT. Neuroinflammation may merit particular attention in future studies.

Efficacy and safety of 3-n-butylphthalide combined with endovascular treatment in acute ischemic stroke due to large vessel occlusion

BACKGROUND

The drug 3-n-butylphthalide (NBP) was developed and approved in China, where it has been used to treat ischemic cerebrovascular diseases. It is also considered to have a neuroprotective effect. This study aimed to evaluate whether NBP combined with endovascular treatment (EVT) can improve the clinical outcome and safety in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO).

METHODS

Data from three studies of patients treated with EVT for AIS due to LVO were combined in this study. Patients of LVO undergoing EVT were dichotomized into NBP and non-NBP subgroups. The primary efficacy outcome was the shift of the modified Rankin Scale (mRS) score at 90 days. The secondary efficacy outcome included favorable functional outcomes, functional independence, and excellent outcome (defined as an mRS score of 3 or less) at 90 days. Safety outcomes included mortality within 90 days and symptomatic intracranial hemorrhage (sICH) within 48 h.

RESULTS

A total of 1820 patients undergoing EVT were included in this study; 628 (37.5%) patients received NBP treatment, whereas 1138 (62.5%) did not. After adjusting for multiple factors, NBP was associated with the improvement of functional outcomes at 90 days (adjusted common odds ratio [OR]: 1.503; 95% confidence interval (CI): 1.254-1.801; p < 0.001). NBP was associated with a higher rate of 90-day favorable outcomes (adjusted OR: 1.589; 95% CI: 1.251-2.020; p < 0.001) and a lower rate of 90-day mortality (adjusted OR: 0.486 [95% CI: 0.372-0.635]; p < 0.001). sICH occurred in 74 of 682 (10.9%) patients in the NBP group and 155 of 1126 (13.8%) patients in the non-NBP group; no statistical difference was detected (adjusted OR: 0.787 [95% CI: 0.567-1.092]; p = 0.152).

CONCLUSION

Among patients with AIS due to LVO, NBP combined with EVT is associated with better functional outcomes and reduced mortality risk without increasing the risk of sICH.

Association between CHADS2, CHA2DS2-VASc, ATRIA, and Essen Stroke Risk Scores and Functional Outcomes in Acute Ischemic Stroke Patients Who Received Endovascular Thrombectomy

Background: CHADS2, CHA2DS2-VASc, ATRIA, and Essen stroke risk scores are used to estimate thromboembolism risk. We aimed to investigate the association between unfavorable outcomes and stroke risk scores in patients who received endovascular thrombectomy (EVT). Methods: This study was performed using data from a nationwide, multicenter registry to explore the selection criteria for patients who would benefit from reperfusion therapies. We calculated pre-admission CHADS2, CHA2DS2-VASc, ATRIA, and Essen scores for each patient who received EVT and compared the relationship between these scores and 3-month modified Rankin Scale (mRS) records. Results: Among the 404 patients who received EVT, 213 (52.7%) patients had unfavorable outcomes (mRS 3−6). All scores were significantly higher in patients with unfavorable outcomes than in those with favorable outcomes. Multivariable logistic regression analysis indicated that CHADS2 and the ATRIA score were positively correlated with unfavorable outcomes after adjusting for body mass index and variables with p < 0.1 in the univariable analysis (CHADS2 score: odds ratio [OR], 1.484; 95% confidence interval [CI], 1.290−1.950; p = 0.005, ATRIA score, OR, 1.128; 95% CI, 1.041−1.223; p = 0.004). Conclusions: The CHADS2 and ATRIA scores were positively correlated with unfavorable outcomes and could be used to predict unfavorable outcomes in patients who receive EVT.

Neutrophil-to-Lymphocyte Ratio Predicts Early Neurological Deterioration after Endovascular Treatment in Patients with Ischemic Stroke

The worsening of neurological status that occurs early after acute ischemic stroke (AIS) remains a serious issue, and the inflammatory response plays a key role in stroke pathobiology. Recently, endovascular treatment (EVT) has revolutionized the management and outcome of patients with AIS due to either extracranial carotid disease or intracranial disease. The neutrophil-to-lymphocyte ratio (NLR) represents an easily available inflammatory biomarker. The aim of the study was to assess the relationship between the NLR at admission and the occurrence of early neurological deterioration (END) in patients with AIS who underwent EVT. Patients with AIS and proximal arterial occlusion in the anterior circulation undergoing EVT were retrospectively identified. Absolute neutrophil count (ANC) and absolute lymphocyte count (ALC) were collected from admission blood work to calculate the NLR. The study outcome was END defined as an increase in at least 4 points in NIHSS score or death between baseline and 24 h after the ischemic event. Patients included were 211, and END occurred in 30 (14.2%). Patients with older age (OR = 1.07, 95% CI: 1.02−1.13), higher serum glucose (OR = 1.01, 95% CI: 1.01−1.02), and higher NLR (OR = 1.011, 95% CI: 1.04−1.18) had an increased risk of END. The best predictive cut-off value of NLR was 6.4, and END occurred in 24.1% and 3.9% of the patients with NLR ≥ 6.4 and <6.4, respectively (p < 0.001). In patients with AIS undergoing EVT, higher NLR values predicted a higher risk of END. Biomarkers able to identify inflammatory mechanisms might identify novel treatment targets and enhance proof-of-concept trials of immunomodulation in stroke.

Pre-thrombectomy prognostic prediction of large-vessel ischemic stroke using machine learning: A systematic review and meta-analysis

Introduction

Machine learning (ML) methods are being increasingly applied to prognostic prediction for stroke patients with large vessel occlusion (LVO) treated with endovascular thrombectomy. This systematic review aims to summarize ML-based pre-thrombectomy prognostic models for LVO stroke and identify key research gaps.

Methods

Literature searches were performed in Embase, PubMed, Web of Science, and Scopus. Meta-analyses of the area under the receiver operating characteristic curves (AUCs) of ML models were conducted to synthesize model performance.

Results

Sixteen studies describing 19 models were eligible. The predicted outcomes include functional outcome at 90 days, successful reperfusion, and hemorrhagic transformation. Functional outcome was analyzed by 10 conventional ML models (pooled AUC=0.81, 95% confidence interval [CI]: 0.77–0.85, AUC range: 0.68–0.93) and four deep learning (DL) models (pooled AUC=0.75, 95% CI: 0.70–0.81, AUC range: 0.71–0.81). Successful reperfusion was analyzed by three conventional ML models (pooled AUC=0.72, 95% CI: 0.56–0.88, AUC range: 0.55–0.88) and one DL model (AUC=0.65, 95% CI: 0.62–0.68).

Conclusions

Conventional ML and DL models have shown variable performance in predicting post-treatment outcomes of LVO without generally demonstrating superiority compared to existing prognostic scores. Most models were developed using small datasets, lacked solid external validation, and at high risk of potential bias. There is considerable scope to improve study design and model performance. The application of ML and DL methods to improve the prediction of prognosis in LVO stroke, while promising, remains nascent.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021266524, identifier CRD42021266524

Machine learning to predict futile recanalization of large vessel occlusion before and after endovascular thrombectomy

Background and purpose

Futile recanalization occurs when the endovascular thrombectomy (EVT) is a technical success but fails to achieve a favorable outcome. This study aimed to use machine learning (ML) algorithms to develop a pre-EVT model and a post-EVT model to predict the risk of futile recanalization and to provide meaningful insights to assess the prognostic factors associated with futile recanalization.

Methods

Consecutive acute ischemic stroke patients with large vessel occlusion (LVO) undergoing EVT at the National Advanced Stroke Center of Nanjing First Hospital (China) between April 2017 and May 2021 were analyzed. The baseline characteristics and peri-interventional characteristics were assessed using four ML algorithms. The predictive performance was evaluated by the area under curve (AUC) of receiver operating characteristic and calibration curve. In addition, the SHapley Additive exPlanations (SHAP) approach and partial dependence plot were introduced to understand the relative importance and the influence of a single feature.

Results

A total of 312 patients were included in this study. Of the four ML models that include baseline characteristics, the “Early” XGBoost had a better performance {AUC, 0.790 [95% confidence intervals (CI), 0.677–0.903]; Brier, 0.191}. Subsequent inclusion of peri-interventional characteristics into the “Early” XGBoost showed that the “Late” XGBoost performed better [AUC, 0.910 (95% CI, 0.837–0.984); Brier, 0.123]. NIHSS after 24 h, age, groin to recanalization, and the number of passages were the critical prognostic factors associated with futile recanalization, and the SHAP approach shows that NIHSS after 24 h ranks first in relative importance.

Conclusions

The “Early” XGBoost and the “Late” XGBoost allowed us to predict futile recanalization before and after EVT accurately. Our study suggests that including peri-interventional characteristics may lead to superior predictive performance compared to a model based on baseline characteristics only. In addition, NIHSS after 24 h was the most important prognostic factor for futile recanalization.

The impact of brain atrophy on the outcomes of mechanical thrombectomy

Objective:

Pre-existing brain atrophy may affect the outcomes of patients treated with mechanical thrombectomy (MT) for large-vessel-occlusion because it is an indicator of low brain reserve. We performed a systematic literature review to assess the impact of brain atrophy on MT-related clinical outcomes.

Methods:

We conducted a systematic search of PubMed, MEDLINE, EMBASE, and Cochrane Library databases from inception to March 2021 using keywords with Boolean operators(“brain atrophy”; “atrophy”; “white matter”; and “thrombectomy”). Articles published in English that evaluated the impact of pre-existing brain atrophy on outcomes of MT-treated acute ischemic stroke were eligible for inclusion.

Results:

Four articles were included. Brain atrophy index was a predictor of mortality (odds ratio [OR]:1.81–1.87, 95% confidence interval [CI]:1.16–2.93) after adjustments for age and white matter lesions. Global cortical atrophy scale was an independent predictor of futile recanalization (OR 1.15, 95% CI 1.08–1.22) in multivariate-adjusted logistic regression. Automated measurement of CSF identified increasing volumes associated with reduced 3-month functional independence and higher modified Rankin scale scores. STandards for ReportIng Vascular changes on Neuroimaging criteria for brain atrophy were associated with unfavorable outcome in ordinal-shift analysis (OR 2.72, 95% CI 1.25–5.91).

Conclusions:

The few studies available highlight heterogeneity of neuroimaging methodologies for assessing brain atrophy and difficulty addressing the multiple confounders involved in clinical outcomes. More consistent, accurate investigation is needed before proposing brain atrophy as a possible parameter to improve patient selection for MT.

Advances in knowledge:

Brain atrophy is associated with many of the clinical confounders frequently present in patients with acute ischemic stroke. Heterogeneity in classification methodologies for brain atrophy and complexity analyzing multiple clinical confounders make it difficult to assess the true impact of this radiological finding on MT-related outcomes.

Posterior Circulation ASPECTS on CT Angiography Predicts Futile Recanalization of Endovascular Thrombectomy for Acute Basilar Artery Occlusion

Background

Acute basilar artery occlusion (BAO) is the most potentially disastrous outcome and has a high risk of recurrence stroke in posterior circulation infarction (PCI). However, the rate of futile recanalization remains high despite successful recanalization. The objective of this study was to investigate 90 days functional outcomes among patients with BAO who underwent endovascular thrombectomy (EVT) and to identify the risk factors associated with futile recanalization.

Methods

We retrospectively analyzed 72 patients with acute BAO who received EVT from January 2018 to June 2021. CT angiography source images posterior circulation Acute Stroke Prognosis Early CT Score (CTA-SI pc-ASPECTS) evaluated the extensive hypoattenuation in patients with BAO. Futile recanalization defined an modified Rankin Scale (mRS) of 3-6 at 90 days despite a successful recanalization. Logistic regression analysis was performed to investigate the predictors of futile recanalization.

Results

Our sample included a total of 55 eligible patients. Patients with poor outcomes showed that the pc-ASPECTS score was lower in patients with poor outcomes than that in patients with good outcomes (P = 0.017). Longer time from symptoms onset-to-the puncture (P = 0.014) and elevation of leucocytes (P = 0.012) were associated with poor outcomes. The multivariable logistic analysis showed that pc-ASPECTS and onset-to-puncture time (OPT) were independent predictors of futile recanalization.

Conclusions

This study suggested that pc-ASPECTS and OPT are independent predictors of futile recanalization after EVT in patients with BAO. The lower pc-ASPECTS score and longer puncture time will have a poor clinical outcome.

Evaluation of Ischemic Penumbra in Stroke Patients Based on Deep Learning and Multimodal CT

In order to investigate the value of multimodal CT for quantitative assessment of collateral circulation, ischemic semidark zone, core infarct volume in patients with acute ischemic stroke (AIS), and prognosis assessment in intravenous thrombolytic therapy, segmentation model which is based on the self-attention mechanism is prone to generate attention coefficient maps with incorrect regions of interest. Moreover, the stroke lesion is not clearly characterized, and lesion boundary is poorly differentiated from normal brain tissue, thus affecting the segmentation performance. To address this problem, a primary and secondary path attention compensation network structure is proposed, which is based on the improved global attention upsampling U-Net model. The main path network is responsible for performing accurate lesion segmentation and outputting segmentation results. Likewise, the auxiliary path network generates loose auxiliary attention compensation coefficients, which compensate for possible attention coefficient errors in the main path network. Two hybrid loss functions are proposed to realize the respective functions of main and auxiliary path networks. It is experimentally demonstrated that both the improved global attention upsampling U-Net and the proposed primary and secondary path attention compensation networks show significant improvement in segmentation performance. Moreover, patients with good collateral circulation have a small final infarct area volume and a good clinical prognosis after intravenous thrombolysis. Quantitative assessment of collateral circulation and ischemic semidark zone by multimodal CT can better predict the clinical prognosis of intravenous thrombolysis.

Translational Stroke Research Review: Using the Mouse to Model Human Futile Recanalization and Reperfusion Injury in Ischemic Brain Tissue

The approach to reperfusion therapies in stroke patients is rapidly evolving, but there is still no explanation why a substantial proportion of patients have a poor clinical prognosis despite successful flow restoration. This issue of futile recanalization is explained here by three clinical cases, which, despite complete recanalization, have very different outcomes. Preclinical research is particularly suited to characterize the highly dynamic changes in acute ischemic stroke and identify potential treatment targets useful for clinical translation. This review surveys the efforts taken so far to achieve mouse models capable of investigating the neurovascular underpinnings of futile recanalization. We highlight the translational potential of targeting tissue reperfusion in fully recanalized mouse models and of investigating the underlying pathophysiological mechanisms from subcellular to tissue scale. We suggest that stroke preclinical research should increasingly drive forward a continuous and circular dialogue with clinical research. When the preclinical and the clinical stroke research are consistent, translational success will follow.

Association of CT-Based Hypoperfusion Index With Ischemic Core Enlargement in Patients With Medium and Large Vessel Stroke

BACKGROUND AND OBJECTIVES

The rate of infarct core progression in patients with acute ischemic stroke is variable and affects outcome of reperfusion therapy. We evaluated the hypoperfusion index (HI) to estimate the initial rate of core progression in patients with medium vessel occlusion (MeVO) compared to large vessel occlusion (LVO) stroke and within a larger time frame since stroke onset.

METHODS

Core progression was assessed in 106 patients with acute stroke and CT perfusion. Using reperfusion trial core time criteria, fast progressors had core >70 mL within 6 hours of stroke onset and slow progressors had core ≤70 mL, mismatch ≥15 mL, and mismatch to core ratio ≥1.8 within 6 to 24 hours. The relationship between HI and infarct core progression (core/time) was examined using receiver operating characteristics to determine optimal HI cutoff. The HI cutoff was then tested in the overall cohort, compared between MeVO and LVO, and evaluated in patients up to 24 hours from stroke onset to differentiate fast from slow rate of core progression. HI threshold was assessed in a second independent cohort of 110 patients with acute ischemic stroke.

RESULTS

In 106 patients with acute stroke, 6.6% were fast progressors, 27.4% were slow progressors, and 66% were not classified as fast or slow progressor by reperfusion trial core time criteria. HI >0.5 was associated with fast progression and able to distinguish fast from slow progressors (area under the curve [AUC] 0.94; 95% confidence interval [CI] 0.80-0.99). In MeVO (n = 26) HI >0.5 had a core progression of 0.30 mL/min compared to 0.03 mL/min for HI ≤0.5 (p < 0.001). In LVO (n = 80), HI >0.5 had a core progression of 0.26 mL/min compared to 0.02 mL/min for HI ≤0.5 (p < 0.001). In patients not classified as fast or slow progressor by reperfusion trial criteria, those with HI >0.5 had progression rate of 0.21 mL/min compared to 0.03 mL/min for those with HI ≤0.5 (p < 0.001). Validation in a second cohort of patients with acute ischemic stroke (n = 110; MeVO = 42, LVO = 68) yielded similar results for HI >0.5 to distinguish fast and slow core progression with an AUC of 0.84 (95% CI 0.72-0.97).

DISCUSSION

HI can differentiate fast from slow core progression in MeVO and LVO within the first 24 hours of acute ischemic stroke. Consideration of core progression rate at time of stroke evaluation may have implications in the selection of patients with MeVO and LVO stroke for reperfusion therapy that warrant further study.

TAB-TICI Score: Successful Recanalization Score After Endovascular Thrombectomy in Acute Stroke

Background and Purpose: Successful reperfusion therapy is supposed to be comprehensive and validated beyond the grade of recanalization. This study aimed to develop a novel scoring system for defining the successful recanalization after endovascular thrombectomy.

Methods: We analyzed the data of consecutive acute stroke patients who were eligible to undergo reperfusion therapy within 24 h of onset and who underwent mechanical thrombectomy using a nationwide multicenter stroke registry. A new score was produced using the predictors which were directly linked to the procedure to evaluate the performance of the thrombectomy procedure.

Results: In total, 446 patients in the training population and 222 patients in the validation population were analyzed. From the potential components of the score, four items were selected: Emergency Room-to-puncture time (T), adjuvant devices used (A), procedural intracranial bleeding (B), and post-thrombectomy reperfusion status [Thrombolysis in Cerebral Infarction (TICI)]. Using these items, the TAB-TICI score was developed, which showed good performance in terms of discriminating early neurological aggravation [AUC 0.73, 95% confidence interval (CI) 0.67–0.78, P < 0.01] and favorable outcomes (AUC 0.69, 95% CI 0.64–0.75, P < 0.01) in the training population. The stability of the TAB-TICI score was confirmed by external validation and sensitivity analyses. The TAB-TICI score and its derived grade of successful recanalization were significantly associated with the volume of thrombectomy cases at each site and in each admission year.

Conclusion: The TAB-TICI score is a valid and easy-to-use tool to more comprehensively define successful recanalization after endovascular thrombectomy in acute stroke patients with large vessel occlusion.

Impact of Prior Statin Use on Reperfusion Rate and Stroke Outcomes in Patients Receiving Endovascular Treatment

Background: We evaluated the impact of prior statin use on successful reperfusion and stroke outcomes after endovascular treatment (EVT). Method: Using consecutive multicenter databases, we enrolled acute ischemic stroke patients receiving EVT between 2015 and 2021. Patients were classified into prior statin users and no prior statin users after a review of premorbid medications. The primary outcome measure was successful reperfusion defined as modified TICI grade 2b or 3 after EVT. Secondary outcome measures were early neurologic deterioration (END) and a 3-month modified Rankin Scale (mRS) score of 0 to 2. Results: Among 385 patients receiving EVT, 74 (19.2%) were prior statin users, who had a significantly higher successful reperfusion rate compared with no prior statin users (94.6% versus 78.8%, p = 0.002). Successful reperfusion and END occurrence were improved according to statin intensity with a dose–response relationship. In multivariate analysis, prior statin was associated with successful reperfusion after EVT (adjusted odds ratio (95% confidence interval) 5.31 (1.67–16.86)). In addition, prior statin was associated with a lower occurrence of END and good functional status. Conclusion: Our study showed that prior statin use before ischemic stroke might improve successful reperfusion and stroke outcomes after EVT.

A Predictive Model for Functional Outcome in Patients with Acute Ischemic Stroke Undergoing Endovascular Thrombectomy

INTRODUCTION

Endovascular thrombectomy (EVT) is a well-established treatment of acute ischemic stroke. Variability in outcomes among thrombectomy patients results in a need for patient centered approaches to recovery. Identifying key factors that are associated with outcomes can help prognosticate and direct resources for continued improvement post-treatment. Thus, we developed a comprehensive predictive model of short-term outcomes post-thrombectomy.

METHODS

This is a retrospective chart review of adult patients who underwent EVT at our institution over the last four years. Primary outcome was dichotomized 90-day mRS (mRS 0-2 v mRS 3-6). Bivariate analyses were conducted, followed by logistic regression modelling via a backward-elimination approach to identify the best fit predictive model.

RESULTS

326 thrombectomies were performed; 230 cases were included in the model. In the final predictive model, adjusting for age, gender, race, diabetes, and presenting NIHSS, pre-admission mRS = 0-2 (OR 18.1; 95% 3.44-95.48; p < 0.001) was the strongest predictor of a good outcome at 90-days. Other independent predictors of good outcomes included being a non-smoker (OR 5.4; 95% CI 1.53-19.00; p = 0.01) and having a post-thrombectomy NIHSS<10 (OR 9.7; 95% CI 3.90-24.27; p < 0.001). A decompressive hemicraniectomy (DHC) was predictive of a poor outcome at 90-days (OR 0.07; 95% CI 0.01-0.72; p = 0.03). This model had a Sensitivity of 79%, a Specificity of 89% and an AUC=0.89.

CONCLUSION

Our model identified low pre-admission mRS score, low post-thrombectomy NIHSS, non-smoker status and not requiring a DHC as predictors of good functional outcomes at 90-days. Future works include developing a prognostic scoring system.

Predictors of futile recanalization in patients undergoing endovascular treatment in the DIRECT-MT trial

BACKGROUND

Futile recanalization-when patients have a successful recanalization but fail to achieve a satisfactory functional outcome- is a common phenomenon of endovascular treatment of acute ischemic stroke (AIS). The present study aimed to identify the predictors of futile recanalization in AIS patients who received endovascular treatment.

METHODS

This is a post-hoc analysis of the DIRECT-MT trial. Demographics, clinical characteristics, acute stroke workflow interval times, biochemical parameters, and imaging characteristics were compared between futile and meaningful recanalization groups. Multivariate analysis was performed to identify the predictors of futile recanalization.

RESULTS

Futile recanalization was observed in 277 patients. In multivariable logistic regression analysis, older age (p<0.001), higher baseline systolic blood pressure (SBP) (p=0.032), incomplete reperfusion defined by extended Thrombolysis In Cerebral Infarction (eTICI) grades (p=0.020), and larger final infarct volume (FIV) (p<0.001) were independent predictors of futile recanalization.

CONCLUSIONS

Old age, high baseline SBP, incomplete reperfusion defined by eTICI, and large FIV were independent predictors of futile recanalization after endovascular therapy for AIS.

Systemic Inflammatory Response Index and Futile Recanalization in Patients with Ischemic Stroke Undergoing Endovascular Treatment

Futile recanalization remains a significant challenge for endovascular treatment (EVT) of acute ischemic stroke (AIS). The inflammatory response that occurs after cerebral infarct plays a central role in stroke pathobiology that can influence the outcome of a recanalization procedure. The aim of this study was to evaluate the relationship between the systemic inflammatory response index (SIRI) and futile recanalization in patients with AIS. We retrospectively identified consecutive patients with ischemic stroke due to proximal arterial occlusion in the anterior circulation, who were treated with EVT and achieved near-complete or complete recanalization. Absolute neutrophil count (ANC), absolute monocyte count (AMC), and absolute lymphocyte count (ALC) were collected from admission blood work to calculate SIRI as ANC × AMC/ALC. The study outcome was futile recanalization, defined as poor functional status [modified Rankin scale (mRS) score ≥ 3] at 3 months despite complete or near-complete recanalization. A total of 184 patients were included. Futile recanalization was observed in 110 (59.8%) patients. Older patients (odds ratio (OR) = 1.07, 95% confidence interval (CI): 1.04–1.10, p < 0.001), higher admission National Institutes of Health stroke scale score (OR = 1.10, 95% CI: 1.02–1.19, p = 0.013), and higher admission SIRI (OR = 1.08, 95% CI: 1.01–1.17, p = 0.028) increased the risk of the poor outcome at 3 months despite complete or near-complete recanalization.

Cystatin C predicts futile recanalization in patients with acute ischemic stroke after endovascular treatment

BACKGROUND

A previous study reported that cystatin C was related to acute ischemic stroke. The association between cystatin C and the clinical outcome in acute ischaemic stroke patients with successful recanalization after endovascular thrombectomy has rarely been reported. This study aimed to evaluate the association between cystatin C and futile recanalization in AIS patients who underwent endovascular thrombectomy.

METHODS

We carried out a retrospective study of acute ischaemic stroke patients with anterior circulation proximal arterial occlusion who achieved complete arterial recanalization after mechanical thrombectomy from May 2017 to April 2020. The patients with complete recanalization were divided into a useful recanalization group and a futile recanalization group according to their 3-month modified Rankin scale score. FR was defined as a modified mRS score of 3-6 at 3 months. Logistic regression analysis was used to identify the risk factors for FR. Receiver operating characteristic curves were used to assess the predictive value of cystatin C for FR.

RESULTS

Of 241 patients, 125 underwent futile recanalization and 116 underwent useful recanalization. Baseline serum cystatin C levels were higher in the futile recanalization group than in the useful recanalization group. After adjustment for potential confounding factors, multivariable adjusted regression models showed that cystatin C was an independent predictor of futile recanalization (odds ratio, 4.111 [95% CI 1.427-11.840], P = 0.009). Receiver operator characteristic (ROC) curve analysis indicated that the model combining cystatin C with other factors model effectively predicted unfavourable outcomes at 3 months (area under the curve = 0.782, p < 0.01).

CONCLUSIONS

A higher level of cystatin C is associated with unfavourable outcomes at 3 months in anterior circulation acute ischaemic stroke patients with endovascular thrombectomy.

Mechanical thrombectomy beyond 6 hours in acute ischaemic stroke with large vessel occlusion in the carotid artery territory: experience at a tertiary hospital

INTRODUCTION

Thrombectomy in the carotid artery territory was recently shown to be effective up to 24 hours after symptoms onset.

METHODS

We conducted a retrospective review of a prospective registry of patients treated at our stroke reference centre between November 2016 and April 2019 in order to assess the safety and effectiveness of mechanical thrombectomy performed beyond 6 hours after symptoms onset in patients with acute ischaemic stroke and large vessel occlusion in the carotid artery territory.

RESULTS

Data were gathered from 59 patients (55.9% women; median age, 71 years). In 33 cases, stroke was detected upon awakening; 57.6% of patients were transferred from another hospital. Median baseline NIHSS score was 16, and median ASPECTS score was 8, with 94.9% of patients presenting > 50% of salvageable tissue. Satisfactory recanalisation was achieved in 88.1% of patients, beyond 24 hours after onset in 5 cases. At 90 days of follow-up, 67.8% were functionally independent; those who were not were older and presented higher prevalence of atrial fibrillation, greater puncture-to-recanalisation time, and higher NIHSS scores, both at baseline and at discharge.

CONCLUSION

In our experience, mechanical thrombectomy beyond 6 hours was associated with good 90-day functional outcomes. Age, NIHSS score, puncture-to-recanalisation time, and presence of atrial fibrillation affected functional prognosis. The efficacy of the treatment beyond 24 hours after onset merits study.

Annexin A1 protects against cerebral ischemia-reperfusion injury by modulating microglia/macrophage polarization via FPR2/ALX-dependent AMPK-mTOR pathway

Background

Cerebral ischemia–reperfusion (I/R) injury is a major cause of early complications and unfavorable outcomes after endovascular thrombectomy (EVT) therapy in patients with acute ischemic stroke (AIS). Recent studies indicate that modulating microglia/macrophage polarization and subsequent inflammatory response may be a potential adjunct therapy to recanalization. Annexin A1 (ANXA1) exerts potent anti-inflammatory and pro-resolving properties in models of cerebral I/R injury. However, whether ANXA1 modulates post-I/R-induced microglia/macrophage polarization has not yet been fully elucidated.

Methods

We retrospectively collected blood samples from AIS patients who underwent successful recanalization by EVT and analyzed ANXA1 levels longitudinally before and after EVT and correlation between ANXA1 levels and 3-month clinical outcomes. We also established a C57BL/6J mouse model of transient middle cerebral artery occlusion/reperfusion (tMCAO/R) and an in vitro model of oxygen–glucose deprivation and reoxygenation (OGD/R) in BV2 microglia and HT22 neurons to explore the role of Ac2-26, a pharmacophore N-terminal peptide of ANXA1, in regulating the I/R-induced microglia/macrophage activation and polarization.

Results

The baseline levels of ANXA1 pre-EVT were significantly lower in 23 AIS patients, as compared with those of healthy controls. They were significantly increased to the levels found in controls 2–3 days post-EVT. The increased post-EVT levels of ANXA1 were positively correlated with 3-month clinical outcomes. In the mouse model, we then found that Ac2-26 administered at the start of reperfusion shifted microglia/macrophage polarization toward anti-inflammatory M2-phenotype in ischemic penumbra, thus alleviating blood–brain barrier leakage and neuronal apoptosis and improving outcomes at 3 days post-tMCAO/R. The protection was abrogated when mice received Ac2-26 together with WRW4, which is a specific antagonist of formyl peptide receptor type 2/lipoxin A4 receptor (FPR2/ALX). Furthermore, the interaction between Ac2-26 and FPR2/ALX receptor activated the 5’ adenosine monophosphate-activated protein kinase (AMPK) and inhibited the downstream mammalian target of rapamycin (mTOR). These in vivo findings were validated through in vitro experiments.

Conclusions

Ac2-26 modulates microglial/macrophage polarization and alleviates subsequent cerebral inflammation by regulating the FPR2/ALX-dependent AMPK-mTOR pathway. It may be investigated as an adjunct strategy for clinical prevention and treatment of cerebral I/R injury after recanalization. Plasma ANXA1 may be a potential biomarker for outcomes of AIS patients receiving EVT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02174-3.

NIHSS Consciousness Score Combined with ASPECTS is a Favorable Predictor of Functional Outcome post Endovascular Recanalization in Stroke Patients

Although revascularization rates after endovascular thrombectomy for large vessel acute ischemic stroke (AIS) are high (71%), only 46% of patients achieve functional independence at 90 days. The present study was designed to explore a new method for predicting the functional prognosis of AIS patients after endovascular recanalization. A total of 200 anterior circulation stroke patients who received endovascular therapy were enrolled. Logistic regression analysis of clinical characteristics on functional independence were performed. The predictive power of sub-items in National Institute of Health stroke scale (NIHSS) and the combination of NIHSS consciousness and Alberta Stroke Program Early CT Score (ASPECTS) on functional independence were assessed by Receiver Operating Characteristic (ROC) curves and the latter was compared with 3 previously published prediction models by AUC (the area under ROC curve). The AUC for the NIHSS consciousness score to predict functional independence was higher than whole NIHSS and other sub-items (0.716 v 0.705, 0.586, 0.573, 0.552 and 0.559). Low NIHSS consciousness score, high ASPECTS score, short time from onset to recanalization, and high rate of successful recanalization were demonstrated to be significantly associated with the functional independence (OR 0.697, 2.226, 0.994 and 28.643). The prediction power of the combination was significantly better than NIHSS and ASPECTS alone (AUC 0.793 v 0.705 and 0.752). Compared with 3 other prediction models, the combination was found to be the strongest predictor for functional independence (AUC 0.793 v 0.791, 0.671 and 0.564). NIHSS which has been shown to be a strong predictor of functional outcomes after endovascular recanalization is largely dependent on the consciousness component. NIHSS consciousness score combined with ASPECTS appears to be a favorable predictor of functional independence. These findings may have broad reaching effects for isolated centers around the world without advanced imaging for triage and prognostication.

Mechanical thrombectomy beyond 6hours in acute ischaemic stroke with large vessel occlusion in the carotid artery territory: Experience at a tertiary hospital

INTRODUCTION

Thrombectomy in the carotid artery territory was recently shown to be effective up to 24hours after symptoms onset.

METHODS

We conducted a retrospective review of a prospective registry of patients treated at our stroke reference centre between November 2016 and April 2019 in order to assess the safety and effectiveness of mechanical thrombectomy performed beyond 6hours after symptoms onset in patients with acute ischaemic stroke and large vessel occlusion in the carotid artery territory.

RESULTS

Data were gathered from 59 patients (55.9% women; median age, 71 years). In 33 cases, stroke was detected upon awakening; 57.6% of patients were transferred from another hospital. Median baseline NIHSS score was 16, and median ASPECTS score was 8, with 94.9% of patients presenting>50% of salvageable tissue. Satisfactory recanalisation was achieved in 88.1% of patients, beyond 24hours after onset in 5 cases. At 90 days of follow-up, 67.8% were functionally independent; those who were not were older and presented higher prevalence of atrial fibrillation, greater puncture-to-recanalisation time, and higher NIHSS scores, both at baseline and at discharge.

CONCLUSION

In our experience, mechanical thrombectomy beyond 6hours was associated with good 90-day functional outcomes. Age, NIHSS score, puncture-to-recanalisation time, and presence of atrial fibrillation affected functional prognosis. The efficacy of the treatment beyond 24hours after onset merits study.

Infarct Growth despite Endovascular Thrombectomy Recanalization in Large Vessel Occlusive Stroke

BACKGROUND AND PURPOSE

Endovascular thrombectomy (EVT) has revolutionized large vessel occlusion stroke care. However, not all patients with good endovascular results achieve good outcomes. We sought to understand the clinical significance of magnetic resonance imaging defined infarct growth despite adequate reperfusion and identify associated clinical and radiographic variables.

METHODS

History, presentation, treatments, and outcomes for consecutive EVT patients at a referral center were collected. Adequate reperfusion was defined as thrombolysis in cerebral infarction (TICI) score 2b-3. Region-specific infarct volumes in white matter, cortex, and basal ganglia were determined on diffusion-weighted imaging. Infarct growth was defined as post-EVT minus pre-EVT volume. Good outcome was defined as 90-day modified Rankin Scale ≤2.

RESULTS

Forty-four patients with adequate reperfusion were identified with median age 72 years; 64% were women. Each region showed infarct growth: white matter (median pre-EVT 7 cubic centimeters [cc], post-EVT 16 cc), cortex (4 cc, 15 cc), basal ganglia (2 cc, 4 cc), total (20 cc, 39 cc). In multivariable regression, total infarct growth independently decreased the odds of good outcome (odds ratio = .946, 95% CI = .897, .998). Further multivariable analyses for determinants of infarct growth identified female sex was associated with less total growth (β = -.294, P = .042), TICI 3 was associated with less white matter growth (β = -.277, P = .048) and cortical growth (β = -.335, P = .017), and both female sex (β = -.332, P = .015) and coronary disease (β = -.337, P = .015) were associated with less cortical growth.

CONCLUSIONS

Infarct growth occurred despite adequate reperfusion, disproportionately in the cortex, and independently decreased the odds of good outcome. Infarct growth occurred while patients were hospitalized and may represent a therapeutic target. Potential determinants of region-specific infarct growth were identified that require confirmation in larger studies.

Risk factors for ineffective recanalization after endovascular treatment in acute ischemic stroke

OBJECTIVE

To assess the risk factors of early ineffective recanalization, defined as a modified Rankin scale (mRS) score of 4∼6 at two weeks after symptom onset, in acute ischemic stroke (AIS) patients receiving endovascular treatment (EVT).

METHOD

One hundred eighty-four AIS patients who received EVT in 01/2016-12/2018 were analyzed. The recanalization rate was 81.5 % (150/184). Patients were divided into effective (mRS 0-3) and ineffective (mRS 4-6) recanalization groups. The independent risk factors for ineffective recanalization were analyzed.

RESULT

The ineffective recanalization rate was 67.3 % (101/150 cases) at 14 days after symptom onset. Twenty-five patients (24.8 %) in the ineffective recanalization group had coronary heart disease, higher than that in the effective group (4 patients, 8.2 %, P = 0.016). Infratentorial pathology accounted for 34.7 % (35 cases) of the ineffective group and only 14.3 % (7 cases) of the control group (P = 0.011). Systolic blood pressure (SBP) was higher in the ineffective group than in the effective group (146 mmHg vs 140 mmHg, P = 0.038). General anesthesia was more common in the ineffective group than in the control group (49 cases, 48.5 %, vs 9 cases, 18.4 %; P = 0.000). Logistic regression showed that coronary heart disease (odds ratio (OR) = 3.399, 95 % confidence interval (CI) 1.013-11.401, P = 0.048), unconsciousness before EVT (OR = 4.292, 95 % CI 1.963-9.386, P = 0.000), SBP (OR = 1.016, 95 % CI 0.997-1.035, P = 0.090) and general anesthesia (OR = 3.378, 95 % CI 1.395-8.180, P = 0.007) were independent risk factors for ineffective recanalization.

CONCLUSION

Patients with coronary heart disease, unconsciousness before EVT, elevated SBP and general anesthesia need precise assessment to benefit from EVT.

Biomarkers of Unfavorable Outcome in Acute Ischemic Stroke Patients with Successful Recanalization by Endovascular Thrombectomy

<b><i>Background:</i></b> We aimed to identify plasma markers of unfavorable outcomes for patients with acute ischemic stroke (AIS) after recanalization by endovascular thrombectomy (EVT). <b><i>Methods:</i></b> From November 2017 to May 2019, we prospectively collected 61 AIS patients due to anterior large vessel occlusion who achieved recanalization by EVT. Plasma samples were obtained between 18 and 24 h after recanalization. Unfavorable outcomes included futile recanalization at 90 days and overall early complications within 7 days after EVT. <b><i>Results:</i></b> After adjustment for age and initial National Institute of Health Stroke Scale (NIHSS), matrix metalloproteinase-9 (MMP-9), tenascin-C, thioredoxin, ADAMTS13, and gelsolin were independently associated with both futile recanalization and overall early complications significantly (all <i>p</i> &#x3c; 0.05), while C-reactive protein (CRP) was independently associated with overall early complications (<i>p</i> = 0.031) but at the limit of significance for futile recanalization (<i>p</i> = 0.051). The baseline clinical model (BCM) (including age and initial NIHSS) demonstrated discriminating ability to indicate futile recanalization (area under the curve [AUC] 0.807, 95% confidence interval [CI] 0.693–0.921) and overall early complications (AUC 0.749, 95% CI 0.611–0.887). BCM+MMP-9+thioredoxin enhanced discrimination (AUC 0.908, 95% CI 0.839–0.978, <i>p</i> = 0.043) and reclassification (net reclassification improvement [NRI] 67.2%, <i>p</i> &#x3c; 0.001) to indicate futile recanalization. With respect to overall early complications, BCM+MMP-9+tenascin-C, BCM+MMP-9+CRP, BCM+MMP-9+ADAMTS13, BCM+tenascin-C+ADAMTS13, and BCM+CRP+ADAMTS13, all improved discrimination (AUC [95% CI]: 0.868 [0.766–0.970], 0.882 [0.773–0.990], 0.886 [0.788–0.984], 0.880 [0.783–0.977], and 0.863 [0.764–0.962], respectively, all <i>p</i> &#x3c; 0.05 by the DeLong method) and reclassification (NRI 59.1%, 71.8%, 51.1%, 67.4%, and 38.3%, respectively, all <i>p</i> &#x3c; 0.05). <b><i>Conclusions:</i></b> The increased levels of MMP-9, tenascin-C, CRP, thioredoxin, and decreased levels of ADAMTS13 and gelsolin were independent predictors of futile recanalization in AIS patients after recanalization by EVT.

Coronary Microvascular Dysfunction

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed "ischemia with non-obstructive coronary artery disease" (INOCA) and for a small proportion of "myocardial infarction with non-obstructive coronary artery disease" (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

Improved collateral flow and reduced damage after remote ischemic perconditioning during distal middle cerebral artery occlusion in aged rats

Circulation through cerebral collaterals can maintain tissue viability until reperfusion is achieved. However, collateral circulation is time limited, and failure of collaterals is accelerated in the aged. Remote ischemic perconditioning (RIPerC), which involves inducing a series of repetitive, transient peripheral cycles of ischemia and reperfusion at a site remote to the brain during cerebral ischemia, may be neuroprotective and can prevent collateral failure in young adult rats. Here, we demonstrate the efficacy of RIPerC to improve blood flow through collaterals in aged (16-18 months of age) Sprague Dawley rats during a distal middle cerebral artery occlusion. Laser speckle contrast imaging and two-photon laser scanning microscopy were used to directly measure flow through collateral connections to ischemic tissue. Consistent with studies in young adult rats, RIPerC enhanced collateral flow by preventing the stroke-induced narrowing of pial arterioles during ischemia. This improved flow was associated with reduced early ischemic damage in RIPerC treated aged rats relative to controls. Thus, RIPerC is an easily administered, non-invasive neuroprotective strategy that can improve penumbral blood flow via collaterals. Enhanced collateral flow supports further investigation as an adjuvant therapy to recanalization therapy and a protective treatment to maintain tissue viability prior to reperfusion.

Association of plasma level of growth differentiation factor-15 and clinical outcome after intraarterial thrombectomy

BACKGROUND AND PURPOSE

As intraarterial thrombectomy (IAT) has been actively practiced, blood biomarkers that can predict outcomes after IAT have drawn attention. Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine and the levels are increased during inflammation or other pathological conditions of various tissues, including the brain. However, GDF-15 levels have not been reported as a biomarker for IAT outcomes. This study was performed to evaluate whether GDF-15 was related to the extent of brain damage and whether it could predict patient prognosis after IAT.

METHODS

Patients who showed large arterial occlusion and significant diffusion-perfusion mismatch on imaging underwent IAT. A total of 62 patients who underwent IAT and had blood samples for GDF-15 measurements were enrolled from July 2013 to May 2015. We assessed the infarct severity by consecutive changes on the National Institutes of Health Stroke Scale (NIHSS) during admission and the size of the infarction on brain imaging. Modified Rankin Scale scores (mRS) from 0 to 2 were considered good outcomes, representing functional independence at discharge and three months later.

RESULTS

The levels of GDF-15 at the time of admission were significantly correlated with the NIHSS scored at 24 hours (r = 0.306, p = 0.016), three days after IAT (r = 0.261, p = 0.041), and at discharge (r = 0.266, p = 0.037), as well as the infarct size on diffusion-weighted image taken 24 h after IAT (r = 0.452, p = 0.001), but the levels were not correlated with the initial NIHSS or the infarct size before IAT. Multiple logistic regression showed that GDF-15 levels were an independent predictor of functional independence (mRS 0 - 2) at discharge (p = 0.028) and three months after IAT (p = 0.019). Other factors that could predict prognosis were good collateral status on the initial brain angiography and rapid recanalization within six hours from symptom onset.

CONCLUSION

The GDF-15 level at the time of admission showed a significant positive correlation with the severity of cerebral damage and clinical outcome after IAT. This suggests that GDF-15 can provide useful prognostic information for patients who successfully underwent IAT in an emergency setting.

Predictors of poor clinical outcome despite complete reperfusion in acute ischemic stroke patients

BACKGROUND

In patients suffering from acute ischemic stroke from large vessel occlusion (LVO), mechanical thrombectomy (MT) often leads to successful reperfusion. Only approximately half of these patients have a favorable clinical outcome. Our aim was to determine the prognostic factors associated with poor clinical outcome following complete reperfusion.

METHODS

Patients treated with MT for LVO from a prospective single-center stroke registry between July 2015 and April 2019 were screened. Complete reperfusion was defined as Thrombolysis in Cerebral Infarction (TICI) grade 3. A modified Rankin scale at 90 days (mRS90) of 3-6 was defined as 'poor outcome'. A logistic regression analysis was performed with poor outcome as a dependent variable, and baseline clinical data, comorbidities, stroke severity, collateral status, and treatment information as independent variables.

RESULTS

123 patients with complete reperfusion (TICI 3) were included in this study. Poor clinical outcome was observed in 67 (54.5%) of these patients. Multivariable logistic regression analysis identified greater age (adjusted OR 1.10, 95% CI 1.04 to 1.17; p=0.001), higher admission National Institutes of Health Stroke Scale (NIHSS) (OR 1.14, 95% CI 1.02 to 1.28; p=0.024), and lower Alberta Stroke Program Early CT Score (ASPECTS) (OR 0.6, 95% CI 0.4 to 0.84; p=0.007) as independent predictors of poor outcome. Poor outcome was independent of collateral score.

CONCLUSION

Poor clinical outcome is observed in a large proportion of acute ischemic stroke patients treated with MT, despite complete reperfusion. In this study, futile recanalization was shown to occur independently of collateral status, but was associated with increasing age and stroke severity.

A Pre-Intervention 4-Item Scale for Predicting Poor Outcome Despite Successful Recanalization in Basilar Artery Occlusion

Poor outcome despite successful recanalization is a relatively common occurrence after endovascular therapy (EVT) in acute intracranial large vessel occlusion. We aimed to develop a simple pre-intervention scale with readily available indicators for predicting the 90-day poor outcome in acute basilar artery occlusion (BAO) patients with successful recanalization after EVT. A prospectively registered consecutive cohort of acute BAO patients treated with EVT in a tertiary stroke center during a 6-year period was reviewed. Poor outcome despite successful recanalization was defined as a 90-day mRS of > 3 despite a post-intervention mTICI of ≥ 2b. A logistic regression analysis was employed to develop the predictive scale. The performance of the scale was estimated by ROC curve and Hosmer-Lemeshow test. Poor outcome was observed in 48 of 109 patients included in this study. The proposed scale consisted of four selected pre-intervention predictors, including the NIHSS score, Pons-Midbrain Index (PMI), bilateral thalamic infarction, and Basilar Artery on Computed Tomography Angiography (BATMAN) collateral score. The 4-item scale revealed good discrimination with an area under curve of 0.83 (95% CI = 0.75-0.90) and acceptable calibration assessed by Hosmer-Lemeshow test (P = 0.48). The optimal cutoff value of the scale (range 0-5 points) was ≥ 3 points with 77% sensitivity, 80% specificity, and 79% accuracy. As a pre-intervention predictive model, the 4-item scale has promising predictive value for poor outcome despite successful recanalization in BAO patients treated with EVT. Nevertheless, external validation with blinded outcome is still needed to confirm its performance before clinical application.