Thrombectomy for Acute Ischemic Stroke: Recent Insights and Future Directions

Fluid excess on intensive care unit after mechanical thrombectomy after acute ischemic stroke is associated with unfavorable neurological and functional outcomes: An observational cohort study

INTRODUCTION

Endovascular thrombectomy stands as a pivotal component in the standard care for patients experiencing acute ischemic stroke with large vessel occlusion. Subsequent care for patients often extends to a neurological intensive care unit. While fluid management is integral to intensive care, the association between early fluid balance and neurological and functional outcomes post-thrombectomy has not yet been thoroughly investigated.

METHODS

In a retrospective analysis of an observational, single-center study spanning from 2015 to 2021 at the University Medical Center Hamburg-Eppendorf, Germany, we enrolled stroke patients who underwent thrombectomy and received subsequent treatment in the ICU. Unfavorable functional and neurological outcome was defined as a mRS > 2 on day 90 after admission (mRS d90) or NIHSS > 5 at discharge, respectively. A multivariate regression model, adjusting for confounders, utilized the average fluid balance in the first 5 days to predict outcomes. Patients were dichotomized by their average fluid balance (>1 L vs <1 L) within the first 5 days, and a multivariate mRS d90 shift analysis was conducted after adjusting for covariates.

RESULTS

Between 2015 and 2021, 1252 patients underwent thrombectomy, and 553 patients met the inclusion criteria (299 women [54%]). Unfavorable functional outcome was significantly associated with a higher daily average fluid balance in the first 5 days in the ICU (mRS d90 ⩽ 2: 0.3 ± 0.5 L, mRS d90 > 2: 0.7 ± 0.7 L, p = 0.02). The same association was observed for the NIHSS at discharge (NIHSS ⩽ 5: 0.3 ± 0.5 L; NIHSS > 5: 0.6 ± 0.6 L; p = 0.03). The mRS d90 shift analysis revealed significance for patients with an average fluid balance <1 L for better functional outcomes (adjusted odds ratio [AOR] 2.17; 95% confidence interval [CI] 1.54-3.07; p < 0.01).

DISCUSSION

Fluid retention in post-thrombectomy stroke patients in the ICU is associated with poorer functional and neurological outcomes. Consequently, fluid retention emerges as an additional potential predictor for post-intervention stroke outcomes. Our findings provide an initial indication that preventing excessive fluid retention in stroke patients after endovascular thrombectomy could be beneficial for both functional and neurological recovery. Therefore, fluid retention might be an element to consider in optimizing fluid management for stroke patients.

Systemic inflammatory response index as a predictor of stroke-associated pneumonia in patients with acute ischemic stroke treated by thrombectomy: a retrospective study

BACKGROUND

The predictive value of systemic inflammatory response index (SIRI) for stroke-associated pneumonia (SAP) risk in patients with acute ischemic stroke (AIS) treated by thrombectomy remains unclear. This study aimed to investigate the predictive value of SIRI for SAP in patients with AIS treated by thrombectomy.

METHODS

We included AIS patients treated by thrombectomy between August 2018 and August 2022 at our institute. We used multivariate logistic regression to construct the prediction model and performed a receiver operating characteristic curve analysis to evaluate the ability of SIRI to predict SAP and constructed a calibration curve to evaluate the prediction accuracy of the model. We evaluated the clinical application value of the nomogram using decision curve analysis.

RESULTS

We included 84 eligible patients with AIS in the analysis, among which 56 (66.7%) had SAP. In the univariate analysis, there were significant differences in sex (p = 0.035), National Institute of Health Stroke Scale score at admission ≥ 20 (p = 0.019) and SIRI (p < 0.001). The results of multivariable logistic analysis showed that the risk of SAP increased with the SIRI value (OR = 1.169, 95% CI = 1.049-1.344, p = 0.014). Age ≥ 60 (OR = 4.076, 95% CI = 1.251-14.841, p = 0.024) was also statistically significant. A nomogram with SIRI showed good prediction accuracy for SAP in AIS patients treated by thrombectomy (C-index value = 0.774).

CONCLUSIONS

SIRI is an independent predictor for SAP in patients with AIS treated by thrombectomy. A high SIRI value may allow for the early identification of patients with AIS treated by thrombectomy at high risk for SAP.

Evaluating high-flow oxygen therapy after mechanical thrombectomy under general anesthesia in acute ischemic stroke: A retrospective single-center study

BACKGROUND

The use of mechanical thrombectomy for acute intracranial vascular occlusion under general anesthesia with endotracheal intubation is well-established as a safe and effective method. However, the process of extubation post-surgery presents challenges for certain patients. This retrospective study assesses the safety and efficacy of combining mechanical ventilation with high-flow oxygen inhalation as an interim strategy, while also examining its impact on long-term clinical outcomes.

METHODS

This research enrolled 119 patients with acute intracranial large vessel occlusion who underwent mechanical thrombectomy under general anesthesia with tracheal intubation between January 2020 and November 2023. Participants were categorized into two groups: Group 1 (n=55), which received high-flow oxygen (HFO) post-extubation, and Group 2 (n=64), which was treated with routine oxygen supplementation (RO). The study compared reintubation and tracheotomy rates between these groups to determine safety and effectiveness. Additionally, it analyzed long-term clinical outcomes by comparing NIHSS and mRS scores before treatment and at 90-day follow-up.

RESULTS

The reintubation rate post-extubation was significantly lower in the HFO group (12.7 %, n=7) compared to the RO group (31.2 %, n=20, p=0.016). The incidence of tracheotomy within 7 days was also reduced in the HFO group compared to the RO group (7.3 %, n=4 vs 20.3 %, n=13, p=0.043). Moreover, a greater proportion of patients in the HFO group achieved mRS scores of 0-2 at 90 days post-stroke than those in the RO group (60 %, n=33 vs 40.6 %, n=26, p=0.035). The median NIHSS score at 90 days was more favorable in the HFO group than in the RO group (6, IQR [1-18] vs 8, IQR [1-20], p=0.005).

CONCLUSION

The study suggests that high-flow oxygen therapy after mechanical thrombectomy under general anesthesia with tracheal intubation may lessen the need for reintubation and tracheotomy, potentially leading to improved long-term prognosis.

Differences in outcome between left-sided and right-sided mechanical thrombectomy for acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Mechanical thrombectomy (MT) is a safe and effective treatment option for acute ischemic stroke due to large vessel occlusion. To investigate differences in outcomes between patients receiving left-sided and right-sided MT, we performed a systematic review and meta-analysis.

METHODS

A systematic literature review was performed using Embase, PubMed, Scopus, and Web of Science databases. Additional literature was searched for manually. Studies reporting safety and efficacy metrics for MT were included. Data regarding the modified Rankin scale (mRS), thrombolysis in cerebral infarction (TICI), symptomatic intracranial hemorrhage (sICH), and 90-day mortality were included. A random-effects model was used to calculate pooled odds ratios (ORs), mean differences (MDs), and 95% confidence intervals (CIs).

RESULTS

The literature search yielded 13 reports consisting of 19 studies ranging from 98 to 5590 patients. Patients presenting with left-sided stroke had a National Institutes of health stroke scale score 2.89 greater than patients presenting with right-sided stroke (MD = 2.89; 95% CI = 2.09-3.68; P-value < 0.001). There were no differences between left-sided and right-sided MT patients for mRS 0-2 (OR = 0.94; 95% CI = 0.85-1.04; P-value = 0.224), TICI 2b-3 (OR = 1.05; 95% CI = 0.88-1.25; P-value = 0.598), sICH (OR = 0.83; 95% CI = 0.61-1.14; P-value = 0.255), or 90-day mortality (OR = 1.06; 95% CI = 0.84-1.33; P-value = 0.610).

CONCLUSIONS

There does not appear to be a difference in outcomes for patients undergoing left-sided or right-sided thrombectomy.

Posterior circulation ischaemic stroke diagnosis and management

This narrative review provides an overview of the posterior circulation and the clinical features of common posterior circulation stroke (PCS) syndromes in the posterior arterial territories and how to distinguish them from mimics. We outline the hyperacute management of patients with suspected PCS with emphasis on how to identify those who are likely to benefit from intervention based on imaging findings. Finally, we review advances in treatment options, including developments in endovascular thrombectomy (EVT) and intravenous thrombolysis (IVT), and the principles of medical management and indications for neurosurgery. Observational and randomised clinical trial data have been equivocal regarding EVT in PCS, but more recent studies strongly support its efficacy. There have been concomitant advances in imaging of posterior stroke to guide optimal patient selection for thrombectomy. Recent evidence suggests that clinicians should have a heightened suspicion of posterior circulation events with the resultant implementation of timely, evidence-based management.

Comparative study of extracellular vesicles derived from mesenchymal stem cells and brain endothelial cells attenuating blood-brain barrier permeability via regulating Caveolin-1-dependent ZO-1 and Claudin-5 endocytosis in acute ischemic stroke

BACKGROUND

Blood-brain barrier (BBB) disruption is a major adverse event after ischemic stroke (IS). Caveolin-1 (Cav-1), a scaffolding protein, played multiple roles in BBB permeability after IS, while the pros and cons of Cav-1 on BBB permeability remain controversial. Numerous studies revealed that extracellular vesicles (EVs), especially stem cells derived EVs, exerted therapeutic efficacy on IS; however, the mechanisms of BBB permeability needed to be clearly illustrated. Herein, we compared the protective efficacy on BBB integrity between bone marrow mesenchymal stem cells derived extracellular vesicles (BMSC-EVs) and EVs from brain endothelial cells (BEC-EVs) after acute IS and investigated whether the mechanism was associated with EVs antagonizing Cav-1-dependent tight junction proteins endocytosis.

METHODS

BMSC-EVs and BEC-EVs were isolated and characterized by nanoparticle tracking analysis, western blotting, and transmission electron microscope. Oxygen and glucose deprivation (OGD) treated b. End3 cells were utilized to evaluate brain endothelial cell leakage. CCK-8 and TRITC-dextran leakage assays were used to measure cell viability and transwell monolayer permeability. Permanent middle cerebral artery occlusion (pMCAo) model was established, and EVs were intravenously administered in rats. Animal neurological function tests were applied, and microvessels were isolated from the ischemic cortex. BBB leakage and tight junction proteins were analyzed by Evans Blue (EB) staining and western blotting, respectively. Co-IP assay and Cav-1 siRNA/pcDNA 3.1 vector transfection were employed to verify the endocytosis efficacy of Cav-1 on tight junction proteins.

RESULTS

Both kinds of EVs exerted similar efficacies in reducing the cerebral infarction volume and BBB leakage and enhancing the expressions of ZO-1 and Claudin-5 after 24 h pMCAo in rats. At the same time, BMSC-EVs were outstanding in ameliorating neurological function. Simultaneously, both EVs treatments suppressed the highly expressed Cav-1 in OGD-exposed b. End3 cells and ischemic cerebral microvessels, and this efficacy was more prominent after BMSC-EVs administration. Cav-1 knockdown reduced OGD-treated b. End3 cells monolayer permeability and recovered ZO-1 and Claudin-5 expressions, whereas Cav-1 overexpression aggravated permeability and enhanced the colocalization of Cav-1 with ZO-1 and Claudin-5. Furthermore, Cav-1 overexpression partly reversed the lower cell leakage by BMSC-EVs and BEC-EVs administrations in OGD-treated b. End3 cells.

CONCLUSIONS

Our results demonstrated that Cav-1 aggravated BBB permeability in acute ischemic stroke, and BMSC-EVs exerted similar antagonistic efficacy to BEC-EVs on Cav-1-dependent ZO-1 and Claudin-5 endocytosis. BMSC-EVs treatment was superior in Cav-1 suppression and neurological function amelioration.

Recombinant pregnancy-specific glycoprotein-1-Fc reduces functional deficit in a mouse model of permanent brain ischaemia

Background

The well-characterised role of the immune system in acute ischaemic stroke has prompted the search for immunomodulatory therapies. Pregnancy-specific glycoproteins (PSGs) are a group of proteins synthesised by placental trophoblasts which show immunomodulatory properties. The aim of this study was to determine whether a proposed PSG1-based therapeutic enhanced recovery in a mouse model of brain ischaemia and to explore possible immunomodulatory effects.

Methods

Mice underwent permanent electrocoagulation of the left middle cerebral artery (pMCAO). They received saline (n = 20) or recombinant pregnancy-specific glycoprotein-1-alpha “fused” to the Fc domain of IgG1 (rPSG1-Fc) (100 μg) (n = 22) at 1 h post-ischaemia. At 3 and 5 days post-ischaemia, neurobehavioural recovery was assessed by the grid-walking test. At 5 days post-ischaemia, lesion size was determined by NeuN staining. Peripheral T cell populations were quantified via flow cytometry. Immunohistochemistry was used to quantify ICAM-1 expression and FoxP3+ cell infiltration in the ischaemic brain. Immunofluorescence was employed to determine microglial activation status via Iba-1 staining.

Results: rPSG1-Fc significantly enhanced performance in the grid-walking test at 3 and 5 days post-ischaemia. No effect on infarct size was observed. A significant increase in circulating CD4⁺ FoxP3+ cells and brain-infiltrating FoxP3+ cells was noted in rPSG1-Fc-treated mice. Among CD4⁺ cells, rPSG1-Fc enhanced the expression of IL-10 in spleen, blood, draining lymph nodes, and non-draining lymph nodes, while downregulating IFN-γ and IL-17 in spleen and blood. A similar cytokine expression pattern was observed in CD8⁺ cells. rPSG1-Fc reduced activated microglia in the infarct core.

Conclusion

The administration of rPSG1-Fc improved functional recovery in post-ischaemic mice without impacting infarct size. Improved outcome was associated with a modulation of the cytokine-secreting phenotype of CD4⁺ and CD8⁺ T cells towards a more regulatory phenotype, as well as reduced activation of microglia. This establishes proof-of-concept of rPSG1-Fc as a potential stroke immunotherapy.

•

rPSG1-Fc enhances functional recovery in a mouse model of permanent brain ischaemia.

•

rPSG1-Fc increases circulating CD4⁺ FoxP3+ cells and brain-infiltrating FoxP3+ cells.

•

rPSG1-Fc increases the expression of IL-10 among CD4⁺ cells in spleen, blood, and lymph nodes.

Efficacy of intravenous thrombolysis combined with mechanical stent interventional thrombectomy on acute ischemic stroke

BACKGROUND

To investigate the efficacy and safety of intravenous thrombolysis combined with mechanical stent interventional thrombectomy in the treatment of acute ischemic stroke.

METHODS

A retrospective analysis was carried out for clinical data of 118 patients with acute ischemic stroke. The patients enrolled were divided into control group (recombinant tissue plasminogen activator (rt-PA) intravenous thrombolysis) and thrombectomy group (mechanical stent interventional thrombectomy based on rt-PA intravenous thrombolysis). The vascular recanalization rate and clinical efficacy after treatment were compared between the two groups. National Institutes of Health Stroke Scale (NIHSS) was used to identify the degree of neurological impairment in all patients before and after treatment, and Barthel Index was used to assess their activity of daily living. Moreover, the changes in the levels of T-lymphocyte subpopulation in peripheral blood and immuno-inflammatory factors before and after treatment were compared, and prognosis of patients and incidence of adverse reactions were recorded.

RESULTS

The response rate inthrombectomy group (93.2%) was significantly better than that in control group (76.3%). The NIHSS sore and modified Rankin scale (mRS) score after treatment were significantly lower than those before treatment, while the Barthel Index after treatment was distinctly higher than that before treatment. The NIHSS score and mRS score in thrombectomy group obviously declined compared with those in control group at 1 month after treatment. The Barthel Index in thrombectomy group was obviously higher than that in control group at 1 month and 2 months after treatment. Levels of cluster of differentiation 3 (CD3)+, CD3+CD4+, CD4+/CD8+ and natural killer (NK) cells in peripheral blood at 6 months after treatment evidently rose compared with those before treatment, while level of CD3+CD8+ evidently declined compared with that before treatment. In thrombectomy group, levels of CD3+, CD3+CD4+, CD4+/CD8+ and NK cells were markedly higher than those in control group, while the level of CD3+CD8+ was markedly lower than that in control group. Besides, in thrombectomy group, levels of serum osteopontin (OPN), malondialdehyde (MDA) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were evidently lower than those in control group at 1 month after treatment, while the level of serum superoxide dismutase (SOD) was evidently higher than that in control group. Compared with that in control group, the acute vascular reocclusion rate in thrombectomy group was significantly decreased at 3 months after treatment (10.2% vs. 22.0%).

CONCLUSIONS

Intravenous thrombolysis combined with mechanical stent interventional thrombectomy can effectively promote the vascular recanalization, improve the neurological function and activity of daily living of patients, reinforce the immunological function, inhibit the oxidative stress response and improve the prognosis of patients.

Efficacy and safety of mechanical thrombectomy in acute stroke patients with pre-morbid disability

INTRODUCTION –

Patients with pre-morbid disability have been generally excluded from randomized controlled trials of mechanical thrombectomy for acute ischemic stroke. However, stroke physicians commonly encounter such patients in practice, and face challenging treatment decisions when caring for them.

AREAS COVERED –

We review the literature on the safety and efficacy of thrombectomy in patients with pre-morbid disability. Recent clinical-epidemiological studies have highlighted the adverse outcomes that come with each increment of additional post-stroke disability in these patients. Several observational studies - both case series and registry-based studies - have helped demonstrate the comparable safety of thrombectomy in patients with pre-morbid disability as in those without, complementing similar data on thrombolysis. These data also suggest similar rates of successful recanalization, symptomatic intracerebral hemorrhage, and return to pre-stroke level of disability when treated with mechanical thrombectomy, although they have higher mortality.

EXPERT OPINION –

In the absence of high-quality evidence, we recommend pursuing shared decision-making with patients or family members and being upfront about the uncertain evidence. Available observational data underline the potential for a substantial proportion of these patients to return to their pre-morbid state, do not indicate a greater rate of treatment-related complications, and do not support routinely excluding these patients from thrombectomy.

Seeing the good in the bad: actual clinical outcome of thrombectomy stroke patients with formally unfavorable outcome

Purpose

Clinical outcome of stroke patients is usually classified into favorable (modified Rankin scale (mRS) 0–2) and unfavorable (mRS 3–5) outcome according to the modified Rankin scale. We took a closer look at the clinical course of thrombectomy stroke patients with formal unfavorable outcome and assessed whether we could achieve our treatment goals and/or neurological improvement in these patients.

Methods

We studied 107 patients with occlusions in the terminal carotid artery or the M1 segment of the middle cerebral artery, in whom complete recanalization (eTICI 3) could be achieved, and who had an mRS of 3–5 at 90 days. We analyzed whether an individual treatment goal (i.e., preventing aphasia) and neurological improvement (NIHSS) could be achieved. In addition, we examined whether there was clinical improvement on the mRS.

Results

The treatment goal was achieved in 52% (53/103) and neurological improvement in 65% (67/103). mRS 90 days post-stroke was better than mRS upon admission in 36% (38/107) and better than or equal to mRS upon admission in 80% (86/107). Of the 93 patients with known pre-stroke mRS, 18% (17/93) already had an mRS ≥ 3, with 15 of these 17 patients having a worse mRS on admission than before. Of these 17 patients, 18% regained baseline, and 24% improved from admission.

Conclusion

Dichotomizing the mRS into favorable and unfavorable outcome does not do justice to the full spectrum of stroke. Patients with formal unfavorable outcome after mRS can improve neurologically, achieve treatment goals, and even regain their admission or pre-stroke mRS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00234-022-02920-1.

Novel brain computed tomography perfusion for cerebral malperfusion secondary to acute type A aortic dissection

OBJECTIVES

The management of acute type A aortic dissection with malperfusion syndrome remains challenging. To evaluate preoperative condition, symptoms might be subjective and objective evaluation of cerebral artery has not yet been established. For quantitative evaluation, this study focused on brain computed tomography perfusion (CTP), which has been recommended by several guidelines of acute ischaemic stroke.

METHODS

In the last 2 years, 147 patients hospitalized due to acute type A aortic dissection were retrospectively reviewed. Among the 23 (16%) patients with cerebral malperfusion, 14 who underwent brain CTP (6 preoperative and 8 postoperative) were enrolled. CTP parameters, including regional blood flow and time to maximum, were automatically computed using RApid processing of Perfusion and Diffusion software. The median duration from the onset to hospital arrival was 129 (31-659) min.

RESULTS

Among the 6 patients who underwent preoperative CTP, 4 with salvageable ischaemic lesion (penumbra: 8-735 ml) without massive irreversible ischaemic lesion (ischaemic core: 0-31 ml) achieved acceptable neurological outcomes after emergency aortic replacement regardless of preoperative neurological severity. In contrast, 2 patients with an ischaemic core of >50 ml (73, 51 ml) fell into a vegetative state or neurological death due to intracranial haemorrhage. CTP parameters guided postoperative blood pressure augmentation without additional supra-aortic vessel intervention in the 8 patients who underwent postoperative CTP, among whom 6 achieved normal neurological function regardless of common carotid true lumen stenosis severity.

CONCLUSIONS

CTP was able to detect irreversible ischaemic core, guide critical decisions in preoperative patients and aid in determining the blood pressure augmentation for postoperative management focusing on residual brain ischaemia.

Clinical and Functional Outcomes of Patients Receiving Cerebral Reperfusion Therapy: A Stroke Databank Study in Brazil

Objectives

Cerebral reperfusion therapy is recommended for the treatment of acute ischemic stroke. However, the outcomes of patients receiving this therapy in middle- and low-income countries should be better defined. This study aimed to evaluate the clinical and functional outcomes of cerebral reperfusion therapy in patients with ischemic stroke.

Materials and Methods

This retrospective study included patients with ischemic stroke treated with cerebral reperfusion therapy, including intravenous thrombolysis (IVT), mechanical thrombectomy (MT), and IVT with MT. The primary outcomes were death and disability, assessed using the modified Rankin scale (mRS), and stroke severity, assessed using the National Institutes of Health Stroke Scale (NIHSS), after intervention and 90 days after ictus. The association between the type of treatment and the primary outcome was assessed using binary logistic regression after adjusting for confounding variables. Furthermore, receiver operating characteristic (ROC) curves were generated to identify the cutoff point of the NIHSS score that could best discriminate the mRS score in all types of treatments.

Results

Patients (n = 291) underwent IVT only (n = 241), MT (n = 21), or IVT with MT (n = 29). In the IVT with MT group, the incidence of death within 90 days increased by five times (OR, 5.192; 95% CI, 2.069-13.027; p = 0.000), prevalence of disability increased by three times (OR, 3.530; 95% CI, 1.376-9.055; p = 0.009) and NIHSS score increased after IVT (from 14.4 ± 6.85 to 17.8 ± 6.36; p = 0.045). There was no significant difference between the initial NIHSS score and that after MT (p = 0.989). Patients' NIHSS score that increased or decreased by 2.5 points had a sensitivity of 0.74 and specificity of 0.65, indicating severe disability or death in these patients.

Conclusion

Altogether, a 2.5-point variation in NIHSS score after reperfusion is an indicator of worse outcomes. In our particular context, patients receiving the combination of IVT and MT had inferior results, which probably reflects challenges to optimize MT in LMIC.

Modulating poststroke inflammatory mechanisms: Novel aspects of mesenchymal stem cells, extracellular vesicles and microglia

Inflammation plays an important role in the pathological process of ischemic stroke, and systemic inflammation affects patient prognosis. As resident immune cells in the brain, microglia are significantly involved in immune defense and tissue repair under various pathological conditions, including cerebral ischemia. Although the differentiation of M1 and M2 microglia is certainly oversimplified, changing the activation state of microglia appears to be an intriguing therapeutic strategy for cerebral ischemia. Recent evidence indicates that both mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (EVs) regulate inflammation and modify tissue repair under preclinical stroke conditions. However, the precise mechanisms of these signaling pathways, especially in the context of the mutual interaction between MSCs or MSC-derived EVs and resident microglia, have not been sufficiently unveiled. Hence, this review summarizes the state-of-the-art knowledge on MSC- and MSC-EV-mediated regulation of microglial activity under ischemic stroke conditions with respect to various signaling pathways, including cytokines, neurotrophic factors, transcription factors, and microRNAs.

Cerebral endothelial cell-derived small extracellular vesicles enhance neurovascular function and neurological recovery in rat acute ischemic stroke models of mechanical thrombectomy and embolic stroke treatment with tPA

Treatment of patients with cerebral large vessel occlusion with thrombectomy and tissue plasminogen activator (tPA) leads to incomplete reperfusion. Using rat models of embolic and transient middle cerebral artery occlusion (eMCAO and tMCAO), we investigated the effect on stroke outcomes of small extracellular vesicles (sEVs) derived from rat cerebral endothelial cells (CEC-sEVs) in combination with tPA (CEC-sEVs/tPA) as a treatment of eMCAO and tMCAO in rat. The effect of sEVs derived from clots acquired from patients who had undergone mechanical thrombectomy on healthy human CEC permeability was also evaluated. CEC-sEVs/tPA administered 4 h after eMCAO reduced infarct volume by ∼36%, increased recanalization of the occluded MCA, enhanced cerebral blood flow (CBF), and reduced blood-brain barrier (BBB) leakage. Treatment with CEC-sEVs given upon reperfusion after 2 h tMCAO significantly reduced infarct volume by ∼43%, and neurological outcomes were improved in both CEC-sEVs treated models. CEC-sEVs/tPA reduced a network of microRNAs (miRs) and proteins that mediate thrombosis, coagulation, and inflammation. Patient-clot derived sEVs increased CEC permeability, which was reduced by CEC-sEVs. CEC-sEV mediated suppression of a network of pro-thrombotic, -coagulant, and -inflammatory miRs and proteins likely contribute to therapeutic effects. Thus, CEC-sEVs have a therapeutic effect on acute ischemic stroke by reducing neurovascular damage.

From Three-Months to Five-Years: Sustaining Long-Term Benefits of Endovascular Therapy for Ischemic Stroke

Background and Purpose: During the months and years post-stroke, treatment benefits from endovascular therapy (EVT) may be magnified by disability-related differences in morbidity/mortality or may be eroded by recurrent strokes and non-stroke-related disability/mortality. Understanding the extent to which EVT benefits may be sustained at 5 years, and the factors influencing this outcome, may help us better promote the sustenance of EVT benefits until 5 years post-stroke and beyond.

Methods: In this review, undertaken 5 years after EVT became the standard of care, we searched PubMed and EMBASE to examine the current state of the literature on 5-year post-stroke outcomes, with particular attention to modifiable factors that influence outcomes between 3 months and 5 years post-EVT.

Results: Prospective cohorts and follow-up data from EVT trials indicate that 3-month EVT benefits will likely translate into lower 5-year disability, mortality, institutionalization, and care costs and higher quality of life. However, these group-level data by no means guarantee maintenance of 3-month benefits for individual patients. We identify factors and associated “action items” for stroke teams/systems at three specific levels (medical care, individual psychosocioeconomic, and larger societal/environmental levels) that influence the long-term EVT outcome of a patient. Medical action items include optimizing stroke rehabilitation, clinical follow-up, secondary stroke prevention, infection prevention/control, and post-stroke depression care. Psychosocioeconomic aspects include addressing access to primary care, specialist clinics, and rehabilitation; affordability of healthy lifestyle choices and preventative therapies; and optimization of family/social support and return-to-work options. High-level societal efforts include improving accessibility of public/private spaces and transportation, empowering/engaging persons with disability in society, and investing in treatments/technologies to mitigate consequences of post-stroke disability.

Conclusions: In the longtime horizon from 3 months to 5 years, several factors in the medical and societal spheres could negate EVT benefits. However, many factors can be leveraged to preserve or magnify treatment benefits, with opportunities to share responsibility with widening circles of care around the patient.

MicroRNA miR-497 is closely associated with poor prognosis in patients with cerebral ischemic stroke

Cerebral ischemic stroke (CIS) is the most common type of stroke, which is highly hazardous. This investigation aims to analyze the correlation of miR-497 with CIS, so as to provide reliable evidence for clinical response to CIS and lay a solid foundation for follow-up research. Eighty-nine CIS patients and 39 concurrent physical examinees selected between June 2017 and October 2018 were enrolled as the research participants. Additionally, SD rats with increased miR-497 expression and normal SD rats were purchased for CIS modeling to observe the clinical implications of miR-497 in CIS, as well as the water content of brain tissue and neuronal apoptosis of rats. miR-497 expression was lower in CIS patients than in physical examinees, and that in patients with complete stroke (CS) was the lowest, which increased after treatment. As determined by the receiver operating characteristic curve (ROC) analysis, miR-497 had an outstanding diagnostic efficacy for CIS and was negatively correlated with the National Institutes of Health Stroke Scale (NIHSS) and MDA concentration, while positively related to SOD concentration. Prognostic follow-up demonstrated that decreased miR-497 expression in patients after treatment predicted an increased risk of prognostic death and recurrence. However, observed in rats, the water content of the brain tissue of rats with increased miR-497 expression was reduced, and the neuronal apoptosis rate of the brain tissue was inhibited. Taken together, with low expression in CIS, miR-497 is strongly related to CIS progression and is a candidate CIS marker.

Early diagnosis and prediction of intracranial hemorrhage using dual-energy computed tomography after mechanical thrombectomy in patients with acute ischemic stroke

PURPOSE

This study assesses the clinical value of dual-energy computed tomography (DECT) in the early diagnosis of intracranial hemorrhage and evaluates the risk of hemorrhagic transformation in patients with acute ischemic stroke (AIS) after mechanical thrombectomy.

METHODS

Patients with AIS who have undergone thrombectomy with Solitaire stent and DECT within one hour after surgery were prospectively enrolled. Linear mixed energy images, virtual non-contrast (VNC) image, and iodine overlay map (IOM) were obtained. Routine CT scan was performed 24 h postoperatively. The sensitivity, specificity, positive and negative predictive values, and accuracy of DECT in the early diagnosis of intracranial hemorrhage was evaluated. The iodine concentration of intracranial lesions was measured by IOM with the follow-up results taken as reference. Receiver operating characteristic (ROC) analysis was performed to obtain the threshold of hemorrhagic transformation and increased bleeding.

RESULTS

Among the 44 patients enrolled in this study, 25 (56.8 %) were diagnosed with simple extravasation of iodinated contrast agent, and 19 (43.2 %) showed intracranial hemorrhage in DECT. Compared with the follow-up CT 24 h after surgery, early diagnosis of postoperative intracranial hemorrhage using DECT demonstrated a sensitivity of 90.5 %, specificity of 100 %, positive predictive rate of 100 %, negative predictive rate of 92.0 %, and accuracy of 95.5 %. Among the 86 intracranial lesions that underwent iodine concentration measurement, 19 were diagnosed with hemorrhagic transformation or increased bleeding, and 67 were diagnosed without the aforementioned conditions. The sensitivity and specificity for differentiating the two groups were 73.7 % and 92.5 %, respectively, with a cut-off value of 2.7 mg/mL.

CONCLUSION

DECT is clinically valuable in early diagnosis and prediction of intracranial hemorrhage after mechanical thrombectomy in AIS patients.

Association of Time of Day When Endovascular Therapy for Stroke Starts and Functional Outcome

OBJECTIVE

To investigate the association between endovascular therapy (EVT) start time in acute ischemic stroke (AIS) and midterm functional outcome.

METHODS

This retrospective cohort study included all patients with AIS treated with EVT from 2 stroke center registries from January 2012 to December 2018. The primary outcome was the score on the modified Rankin Scale (mRS) and the utility-weighted mRS (uw-mRS) at 90 days. A proportional odds model was used to calculate the common odds ratio (OR) as a measure of the likelihood that the intervention at a given EVT start time would lead to lower scores on the mRS (shift analysis).

RESULTS

A total of 1,558 cases were equally allotted into 12 EVT start time periods. The primary outcome favored EVT start times in the morning at 08:00-10:20 and 10:20-11:34 (OR, 0.53; 95% confidence interval [CI], 0.38 to 0.75; p < 0.001; OR, 0.62; 95% CI, 0.44 to 0.87; p = 0.006, respectively), while it disfavored EVT start times at the end of the working day at 15:55-17:15 and 18:55-20:55 (OR, 1.47; 95% CI, 1.03-2.09; p = 0.034; OR, 1.49; 95% CI, 1.03-2.15; p = 0.033). Symptom onset to EVT start time was significantly higher and use of IV tissue plasminogen activator significantly lower between 10:20 and 11:34 (p < 0.004 and p = 0.012, respectively).

CONCLUSION

EVT for AIS in the morning leads to better midterm functional outcome, while EVT at the end of the work day leads to poorer midterm functional outcome. Difference in baseline factors, standard workflow, and technical efficacy metrics could not be identified as potential mediators of this effect.

Serum Levels of Soluble Triggering Receptor Expressed on Myeloid Cells-1 Associated with the Severity and Outcome of Acute Ischemic Stroke

Stroke is a neurological emergency, where the mechanism of the blood supply to the brain is impaired, resulting in brain cell ischemia and death. Neuroinflammation is a key component in the ischemic cascade that results in cell damage and death after cerebral ischemia. The triggering receptor expressed on myeloid cells-1 (TREM-1) modulates neuroinflammation after acute ischemic stroke. In the present study, 60 patients with acute ischemic stroke, who had been subjected to neurological examinations and National Institutes of Health Stroke Scale (NIHSS) and brain magnetic resonance imaging studies, were enrolled in the emergency room of Kaohsiung Chang Gung Memorial Hospital. Twenty-four healthy volunteers were recruited as controls. The serum levels of soluble TREM-1 (sTREM-1), human S100 calcium-binding protein B (S100B), and proinflammatory cytokines and chemokines, including tumor necrosis α (TNF-α), interleukin 1β, interleukin 6 (IL-6), interleukin 8, and interferon-γ were measured immediately after acute ischemic stroke. The serum levels of sTREM-1, TNFα, IL-6, and S100B were correlated with the stroke volume and NIHSS, after acute ischemic stroke. Additionally, the serum levels of sTREM-1 were significantly positively correlated with S100B. The functional outcomes were evaluated 6 months after ischemic stroke by the Barthel index, which was correlated with the age and levels of sTREM-1 and S100B. We suggest that acute ischemic stroke induces neuroinflammation by the activation of the TREM-1 signaling pathway and the downstream inflammatory machinery that modulates the inflammatory response and ischemic neuronal cell death. From a translational perspective, our results may allow for the development of a new therapeutic strategy for acute ischemic stroke by targeting the TREM-1 signaling pathway.

Mechanical Thrombectomy in Patients With Acute Ischemic Stroke: A Comparison of Transradial Versus Transfemoral Cerebral Angiography

Stroke is the fourth leading cause of death in the United States and the primary reason for long-term disability. This debilitating condition can be divided into ischemic stroke and hemorrhagic stroke. The former occurs in almost 90% of all cases and arises from the occlusion of the supplying artery. Over the years, the management of stroke has developed from solely medical treatment to that which combines medical with mechanical treatment. Mechanical thrombectomy (MT) has drawn considerable interest in advanced medicine and is becoming more widely available. The two fundamental techniques in opening an occluded vessel are the transfemoral and transradial approaches. This literature review aims to compare the clinical implications, complication rate, and overall outcome between the transfemoral and transradial approaches in endovascular intervention in patients with acute ischemic stroke. We conducted a literature review on ischemic stroke and searched PubMed and Google Scholar for relevant articles published from January 2010 to March 2020. Mechanical thrombectomy has become the standard of care for patients with brain ischemia. The transradial approach exhibited superiority to the transfemoral route in resolving symptoms, decreased complication rates, and reduced healthcare costs in a subset of patients. In this literature review, the comparison between the two procedures reveals that the outcomes for anterior circulation stroke and posterior vascular system stroke may vary. Further research needs to be conducted to improve procedural skills and decrease technical difficulties, ultimately resulting in improved overall patient outcomes with respect to health and comfort.

Endovascular Therapy or Alteplase in Patients with Comorbidities: Insights from UNMASK EVT

OBJECTIVE

Decisions to treat large-vessel occlusion with endovascular therapy (EVT) or intravenous alteplase depend on how physicians weigh benefits against risks when considering patients' comorbidities. We explored EVT/alteplase decision-making by stroke experts in the setting of comorbidity/disability.

METHODS

In an international multi-disciplinary survey, experts chose treatment approaches under current resources and under assumed ideal conditions for 10 of 22 randomly assigned case scenarios. Five included comorbidities (cancer, cardiac/respiratory/renal disease, mild cognitive impairment [MCI], physical dependence). We examined scenario/respondent characteristics associated with EVT/alteplase decisions using multivariable logistic regressions.

RESULTS

Among 607 physicians (38 countries), EVT was chosen less often in comorbidity-related scenarios (79.6% under current resources, 82.7% assuming ideal conditions) versus six "level-1A" scenarios for which EVT/alteplase was clearly indicated by current guidelines (91.1% and 95.1%, respectively, odds ratio [OR] [current resources]: 0.38, 95% confidence interval 0.31-0.47). However, EVT was chosen more often in comorbidity-related scenarios compared to all other 17 scenarios (79.6% versus 74.4% under current resources, OR: 1.34, 1.17-1.54). Responses favoring alteplase for comorbidity-related scenarios (e.g. 75.0% under current resources) were comparable to level-1A scenarios (72.2%) and higher than all others (60.4%). No comorbidity independently diminished EVT odds when considering all scenarios. MCI and dependence carried higher alteplase odds; cancer and cardiac/respiratory/renal disease had lower odds. Being older/female carried lower EVT odds. Relevant respondent characteristics included performing more EVT cases/year (higher EVT-, lower alteplase odds), practicing in East Asia (higher EVT odds), and in interventional neuroradiology (lower alteplase odds vs neurology).

CONCLUSION

Moderate-to-severe comorbidities did not consistently deter experts from EVT, suggesting equipoise about withholding EVT based on comorbidities. However, alteplase was often foregone when respondents chose EVT. Differences in decision-making by patient age/sex merit further study.

PI3Kγ (Phosphoinositide 3-Kinase-γ) Inhibition Attenuates Tissue-Type Plasminogen Activator-Induced Brain Hemorrhage and Improves Microvascular Patency After Embolic Stroke

Genetic and pharmacological inhibition of the PI3Kγ (phosphoinositide 3-kinase-γ) exerts anti-inflammatory and protective effects in a number of inflammatory and autoimmune diseases. SHRs (spontaneously hypertensive rats) subjected to embolic middle cerebral occlusion were treated with AS605240 (30 mg/kg) at 2 or 4 hours, tPA (tissue-type plasminogen activator; 10 mg/kg) at 2 or 6 hours, or AS605240 at 4 hours plus tPA at 6 hours. Infarct volume, brain hemorrhage, neurological function, microvascular thrombosis, and cerebral microvessel patency were examined. We found that treatment with AS605240 alone at 2 hours or the combination treatment with AS605240 at 4 hours and tPA at 6 hours significantly reduced infarct volume and neurological deficits at 3 days after stroke compared with ischemic rats treated with saline, AS605240 alone at 4 hours, and tPA alone at 6 hours. Moreover, the combination treatment effectively prevented the delayed tPA-induced cerebral hemorrhage. These protective effects are associated with reduced disruption of the blood-brain barrier, reduced downstream microvascular thrombosis, and improved microvascular patency by AS605240. Inhibition of the NF-κB (nuclear transcription factor-κB)-dependent MMP (matrix metalloproteinase)-9 and PAI-1 (plasminogen activator inhibitor-1) in the ischemic brain endothelium may underlie the neurovascular protective effect of AS605240. In addition, the combination treatment significantly reduced circulating platelet P-selectin expression and platelet-leukocyte aggregation compared with ischemic rats treated with saline or tPA alone at 6 hours. In conclusion, inhibition of PI3Kγ with AS605240 reduces delayed tPA-induced intracerebral hemorrhage and improves microvascular patency, which likely contributes to neuroprotective effect of the combination treatment.

N-Acetyl-Seryl-Aspartyl-Lysyl-Proline Augments Thrombolysis of tPA (Tissue-Type Plasminogen Activator) in Aged Rats After Stroke

Background and Purpose- Stroke is a leading cause of disability worldwide, mainly affecting the elderly. However, preclinical studies in aged ischemic animals are limited. N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) is a naturally occurring tetrapeptide with vascular-protective properties. The present study investigated the effect of AcSDKP on tPA (tissue-type plasminogen activator)-induced thrombolysis in aged rats after ischemic stroke. Methods- Aged male rats (18 months) were subjected to embolic middle cerebral artery occlusion. Rats subjected to 4 hours of middle cerebral artery occlusion were randomized into the following groups: (1) AcSDKP; (2) tPA; (3) AcSDKP in combination with tPA; and (4) saline. Neurological deficits, cerebral microvascular patency and integrity, and infarction were examined at 1 day and 7 days after middle cerebral artery occlusion. In vitro experiments were performed to examine the effect of AcSDKP on aged cerebral endothelial cell permeability. Results- Compared with saline, AcSDKP, or tPA as monotherapy did not have any therapeutic effects, whereas AcSDKP in combination with tPA significantly reduced cerebral tissue infarction and improved neurological outcome without increasing cerebral hemorrhage. Concurrently, the combination treatment significantly augmented microvascular perfusion and reduced thrombosis and blood-brain barrier leakage. In vitro, compared with cerebral endothelial cells from ischemic adult rats, the endothelial cells from ischemic aged rats exhibited significantly increased leakage. AcSDKP suppressed tPA-induced aged endothelial cell leakage and reduced expression of ICAM-1 (intercellular adhesion molecule 1) and NF (nuclear factor)-κB. Conclusions- The present study provides evidence for the therapeutic efficacy of AcSDKP in combination tPA for the treatment of embolic stroke in aged rats at 4 hours after stroke onset. AcSDKP likely acts on cerebral endothelial cells to enhance the benefits of tPA by increasing tissue perfusion and augmenting the integrity of the blood-brain barrier. Visual Overview- An online visual overview is available for this article.

Is intravenous thrombolysis still necessary in patients who undergo mechanical thrombectomy?

PURPOSE OF REVIEW

To summarize available evidence on the potential utility of pretreatment with intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA) in acute ischemic stroke (AIS) patients with large vessel occlusions (LVO) who are treated with mechanical thrombectomy.

RECENT FINDINGS

Despite theoretical concerns of a higher bleeding risk with IVT pretreatment, there are no data showing increased risk of symptomatic intracerebral hemorrhage (sICH) in patients with LVO receiving bridging therapy (IVT and mechanical thrombectomy) compared with direct mechanical thrombectomy (dMT). Additionally, evidence from observational studies suggest lower rates of infarctions in previously unaffected territories and higher rates of successful reperfusion, with lower number of device passes, in patients receiving bridging therapy. There are substantial discrepancies in studies comparing clinical outcomes between dMT and bridging therapy that are directly related to the inclusion of patients with contraindications to IVT in the dMT group. Ongoing clinical trials will provide definitive answers on the potential additional benefit of IVT in LVO patients receiving mechanical thrombectomy.

SUMMARY

IVT and mechanical thrombectomy are two effective reperfusion therapies that should be used in a swift and noncompeting fashion in AIS patients. AIS patients with LVO and no contraindications for IVT should receive promptly rt-PA bolus followed by immediate initiation of mechanical thrombectomy as indicated by current international recommendations, unless future randomized controlled trials provide evidence to proceed differently.

Exosomes - beyond stem cells for restorative therapy in stroke and neurological injury

Stroke is a leading cause of disability worldwide, and brain injuries devastate patients and their families, but currently no drugs on the market promote neurological recovery. Limited spontaneous recovery of function as a result of brain remodelling after stroke or injury does occur, and cell-based therapies have been used to promote these endogenous processes. Increasing evidence is demonstrating that the positive effects of such cell-based therapy are mediated by exosomes released from the administered cells and that the microRNA cargo in these exosomes is largely responsible for the therapeutic effects. This evidence raises the possibility that isolated exosomes could be used alone as a neurorestorative therapy and that these exosomes could be tailored to maximize clinical benefit. The potential of exosomes as a therapy for brain disorders is therefore being actively investigated. In this Review, we discuss the current knowledge of exosomes and advances in our knowledge of their effects on endogenous neurovascular remodelling events. We also consider the opportunities for exosome-based approaches to therapeutic amplification of brain repair and improvement of recovery after stroke, traumatic brain injury and other diseases in which neurorestoration could be a viable treatment strategy.

Complete clot ingestion with cyclical ADAPT increases first-pass recanalization and reduces distal embolization

BACKGROUND

Evidence is mounting that first-pass complete recanalization during mechanical thrombectomy is associated with better clinical outcomes in patients presenting with an emergent large vessel occlusion. We hypothesize that aspiration achieving complete clot ingestion results in higher first-pass successful recanalization with quantitative reduction in distal emboli.

METHODS

A patient-specific cerebrovascular replica was connected to a flow loop. Occlusion of the middle cerebral artery was achieved with clot analogs. Independent variables were the diameter of the aspiration catheter (0.054-0.088in) and aspiration pattern (static versus cyclical). Outcome measures were the first-pass rates of complete clot ingestion, the extent of recanalization, and the particle-size distribution of distal emboli.

RESULTS

All aspiration catheters were successfully navigated to the occlusion. Complete clot ingestion during aspiration thrombectomy resulted in first-pass complete recanalization in every experiment, only achieved in 21% of experiments with partial ingestion (P<0.0001). Aspiration through the large bore 0.088in device resulted in the highest rates of complete clot ingestion (90%). Cyclical aspiration (18-29 inHg, 0.5 Hz) significantly increased the rate of complete clot ingestion (OR21 [1.6, 266]; P=0.04). In all experiments, complete clot ingestion resulted in fewer and smaller distal emboli.

CONCLUSIONS

Complete clot ingestion results in fewer distal emboli and the highest rates of first-pass complete recanalization. The rate of complete ingestion during aspiration thrombectomy is a function of both the inner diameter of the aspiration catheter and use of cyclical aspiration.