A trial of imaging selection and endovascular treatment for ischemic stroke

What You Always Wanted to Know about Endovascular Therapy in Acute Ischemic Stroke but Never Dared to Ask: A Comprehensive Review

In 2015, mechanical thrombectomy (MT) in combination with intravenous thrombolysis was demonstrated to be superior to best medical treatment alone in patients with anterior circulation stroke. This finding resulted in an unprecedented boost in endovascular stroke therapy, and MT became widely available. MT was initially approved for patients presenting with large vessel occlusion in the anterior circulation (intracranial internal carotid artery or proximal middle cerebral artery) within a 6-hour time window. Eventually, it was shown to be beneficial in a broader group of patients, including those without known symptom-onset, wake-up stroke, or patients with posterior circulation stroke. Technical developments and the implementation of novel thrombectomy devices further facilitated endovascular recanalization for acute ischemic stroke. However, some aspects remain controversial. Is MT suitable for medium or very distal vessel occlusions? Should emergency stenting be performed for symptomatic stenosis or recurrent occlusion? How should patients with large vessel occlusion without disabling symptoms be treated? Do certain patients benefit from MT without intravenous thrombolysis? In the era of personalized decision-making, some of these questions require an individualized approach based on comorbidities, imaging criteria, and the severity or duration of symptoms. Despite its successful development in the past decade, endovascular stroke therapy will remain a challenging and fascinating field in the years to come. This review aims to provide an overview of patient selection, and the indications for and execution of MT in patients with acute ischemic stroke.

Use of evidence in acute stroke decision-making: Implications for evidence-based medicine

RATIONALE, AIMS AND OBJECTIVES

Evidence-Based Medicine proposes a prescriptive model of physician decision-making in which 'best evidence' is used to guide best practice. And yet, proponents of EBM acknowledge that EBM fails to offer a systematic theory of physician decision-making.

METHODS

In this paper, we explore how physicians from the neurology and emergency medicine communities have responded to an evolving body of evidence surrounding the acute treatment of patients with ischemic stroke. Through analysis of this case study, we argue that EBM's vision of evidence-based medical decision-making fails to appreciate a process that we have termed epistemic evaluation.

RESULTS AND CONCLUSIONS

Physicians are required to interpret and apply any knowledge-even what EBM would term 'best evidence'-in light of their own knowledge, background and experience. This is consequential for EBM as understanding what physicians do and why they do it would appear to be essential to achieving optimal practice in accordance with best evidence.

Frictional force analysis of stent retriever devices using a realistic vascular model: Pilot study

Objective

To date, no vascular model to analyze frictional forces between stent retriever devices and vessel walls has been designed to be similar to the real human vasculature. We developed a novel in vitro intracranial cerebrovascular model and analyzed frictional forces of three stent retriever devices.

Methods

A vascular mold was created based on digital subtraction angiography of a patient's cerebral vessels. The vascular model was constructed using polydimethylsiloxane (PDMS, Dow Corning, Inc.) as a silicone elastomer. The vascular model was coated on its inner surface with a lubricating layer to create a low coefficient of friction (~0.037) to closely approximate the intima. A pulsatile blood pump was used to produce blood flow inside the model to approximate real vascular conditions. The frictional forces of Trevo XP, Solitaire 2, and Eric 4 were analyzed for initial and maximal friction retrieval forces using this vascular model. The total pulling energy generated during the 3 cm movement was also obtained.

Results

Results for initial retrieval force were as follows: Trevo, 0.09 ± 0.04 N; Solitaire, 0.25 ± 0.07 N; and Eric, 0.33 ± 0.21 N. Results for maximal retrieval force were as follows: Trevo, 0.36 ± 0.07 N; Solitaire, 0.54 ± 0.06 N; and Eric, 0.80 ± 0.13 N. Total pulling energy (N·cm) was 0.40 ± 0.10 in Trevo, 0.65 ± 0.10 in Solitaire, and 0.87 ± 0.14 in Eric, respectively.

Conclusions

Using a realistic vascular model, different stent retriever devices were shown to have statistically different frictional forces. Future studies using a realistic vascular model are warranted to assess SRT devices.

Reperfusion therapy in acute ischemic stroke

Background: Until mid-2010, intravenous thrombolysis remains the only reperfusion therapy for acute ischemic stroke. In 2015, the five pivotal endovascular recanalization therapy (ERT) trials demonstrated that ERT improved the prognosis of acute ischemic stroke with large artery occlusion within 6 hours after onset. Currently, ERT has been established as a crucial acute ischemic stroke treatment option. The prognosis of acute ischemic stroke is known to be time-dependent. Several studies addressed that ERT expands the time window for reperfusion therapy; thereby, improving prognosis.Current Concepts: Recent randomized clinical trials revealed that ERT improved the outcome in patients even within the late time window of up to 24 hours of stroke onset. The trials enrolled participants who had target mismatch, defined as either clinical-core or perfusion-core mismatch, which prompted an update of the national guidelines in several countries. To select the patients with stroke who were eligible for ERT, advanced imaging tools could be recommended.Discussion and Conclusion: According to the updated ERT guidelines, stroke centers were recommended to establish an appropriate imaging protocol and strategy for patients with acute ischemic stroke who were within the late time window. Additionally, if ERT is further practiced nationally, more manpower and infrastructure for patients with stroke should be supported at the stroke center.

Acute Neurointervention for Ischemic Stroke

Acute ischemic stroke (AIS) is one of the major causes of death worldwide and a leading cause of disability. Until recently treatment of AIS was supportive, and in a minority of patients intravenous thrombolysis was available but with marginal clinical benefit. With the advent of stent retrievers, distal aspiration catheters as well as improved patient selection neurologic outcomes have greatly improved. However, the care of patients with AIS is still challenging and requires the early recognition of stroke symptoms, extensive diagnostic testing, early intervention, and advanced nursing and critical care.

Detection, Diagnosis and Treatment of Acute Ischemic Stroke: Current and Future Perspectives

Stroke is one of the leading causes of disability worldwide. Early diagnosis and treatment of stroke are important for better clinical outcome. Rapid and accurate diagnosis of stroke subtypes is critical. This review discusses the advantages and disadvantages of the current diagnostic and assessment techniques used in clinical practice, particularly for diagnosing acute ischemic stroke. Alternative techniques for rapid detection of stroke utilizing blood based biomarkers and novel portable devices employing imaging methods such as volumetric impedance phase-shift spectroscopy, microwave tomography and Doppler ultrasound are also discussed. Current therapeutic approaches for treating acute ischemic stroke using thrombolytic drugs and endovascular thrombectomy are discussed, with a focus on devices and approaches recently developed to treat large cranial vessel occlusions.

CBX2 shapes chromatin accessibility promoting AML via p38 MAPK signaling pathway

Background

The dynamic epigenome and proteins specialized in the interpretation of epigenetic marks critically contribute to leukemic pathogenesis but also offer alternative therapeutic avenues. Targeting newly discovered chromatin readers involved in leukemogenesis may thus provide new anticancer strategies. Accumulating evidence suggests that the PRC1 complex member CBX2 is overexpressed in solid tumors and promotes cancer cell survival. However, its role in leukemia is still unclear.

Methods

We exploited reverse genetic approaches to investigate the role of CBX2 in human leukemic cell lines and ex vivo samples. We also analyzed phenotypic effects following CBX2 silencing using cellular and molecular assays and related functional mechanisms by ATAC-seq and RNA-seq. We then performed bioinformatic analysis of ChIP-seq data to explore the influence of histone modifications in CBX2-mediated open chromatin sites. Lastly, we used molecular assays to determine the contribution of CBX2-regulated pathways to leukemic phenotype.

Results

We found CBX2 overexpressed in leukemia both in vitro and ex vivo samples compared to CD34⁺ cells. Decreased CBX2 RNA levels prompted a robust reduction in cell proliferation and induction of apoptosis. Similarly, sensitivity to CBX2 silencing was observed in primary acute myeloid leukemia samples. CBX2 suppression increased genome-wide chromatin accessibility followed by alteration of leukemic cell transcriptional programs, resulting in enrichment of cell death pathways and downregulation of survival genes. Intriguingly, CBX2 silencing induced epigenetic reprogramming at p38 MAPK-associated regulatory sites with consequent deregulation of gene expression.

Conclusions

Our results identify CBX2 as a crucial player in leukemia progression and highlight a potential druggable CBX2-p38 MAPK network in AML.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01603-y.

Clot composition characterization using diffuse reflectance spectroscopy in acute ischemic stroke

Acute ischemic stroke caused by large vessel occlusion is treated with endovascular thrombectomy, but treatment failure may occur when clot composition and thrombectomy technique mismatch. In this proof-of-concept study, diffuse reflectance spectroscopy (DRS) is evaluated for identification of clot composition ex vivo. DRS spectra and histology were acquired from 45 clot units retrieved from 29 stroke patients. DRS spectra correlated to clot RBC content, R= 81, p < .001, and could discriminate between RBC-rich and fibrin-rich clots, p < 0.001. Sensitivity and specificity for detection of RBC-rich clots were 0.722 and 0.846 respectively. Applied in an intravascular device, DRS could potentially provide intraprocedural information on clot composition that could increase endovascular thrombectomy efficiency.

The End of Tissue-Type Plasminogen Activator's Reign?

Mechanical thrombectomy is a highly effective treatment for acute ischemic stroke caused by large-vessel occlusion in the anterior cerebral circulation, significantly increasing the likelihood of recovery to functional independence. Until recently, whether intravenous thrombolysis before mechanical thrombectomy provided additional benefits to patients with acute ischemic stroke-large-vessel occlusion remained unclear. Given that reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke-large-vessel occlusion and the efficacy of both intravenous thrombolysis and mechanical thrombectomy is time-dependent, achieving complete reperfusion with a single pass should be the primary angiographic goal. However, it remains undetermined whether extending the procedure with additional endovascular attempts or local lytics administration safely leads to higher reperfusion grades and whether there are significant public health and cost implications. Here, we outline the current state of knowledge and research avenues that remain to be explored regarding the consistent therapeutic benefit of intravenous thrombolysis in anterior circulation strokes and the potential place of adjunctive intra-arterial lytics administration, including alternative thrombolytic agent place.

Practicalities of Impracticability: An Interim Review of Randomized Controlled Trials

Impracticability is an ethical standard for waiver of informed consent in research. We examine how well the criterion of impracticability appears to have been fulfilled in a set of 36 completed randomized controlled trials (RCTs) that secured consent from some subjects or LARs and employed waivers to enroll others. These trials were identified among 155 RCTs using waivers of consent in a convenience sample drawn from 7 systematic reviews. Recruitment data were available for 19 of the 36 trials, revealing an average of 41.6% of subjects (range 0.2-98.7%, 95% CI: 24.8-58.4%) were enrolled without consent. Six trials enrolled less than 10% of subjects without consent and an overlapping set of 9 trials sought consent from all subjects or LARs at some sites while waiving consent at other sites. We question whether these trials were practicable without waivers and identify issues for consideration by investigators and ethics review boards.

Mechanical thrombectomy with retrievable stents and aspiration catheters for acute ischaemic stroke: a meta-analysis of randomised controlled trials

BACKGROUND

Retrievable stents and aspiration catheters have been developed to provide more effective arterial recanalisation in acute ischaemic stroke.

AIMS

The aim of this analysis was to test the effect of mechanical thrombectomy on mortality and long-term neurological outcome in patients presenting with acute large-vessel anterior circulation ischaemic stroke.

METHODS

A structured search identified randomised controlled trials of thrombectomy (using a retrievable stent or aspiration catheter) versus control on a background of medical therapy which included intravenous thrombolysis if appropriate. The primary endpoint was disability at 90-day follow-up as assessed by the modified Rankin scale (mRS). Secondary endpoints included all-cause mortality and symptomatic intracranial haemorrhage. A Bayesian mixed-effects model was used for analysis.

RESULTS

Twelve trials met the inclusion criteria, comprising a total of 1,276 patients randomised to thrombectomy and 1,282 patients to control. Randomisation to thrombectomy significantly reduced disability at 90 days (odds ratio [OR] 0.52, 95% credible interval [CrI] 0.46 to 0.61, probability(control better)<0.0001). Furthermore, thrombectomy reduced the odds of functional dependence at 90 days, indicated by an mRS score >2 (OR 0.44, CrI 0.37 to 0.52, p<0.0001). Thrombectomy reduced all-cause mortality at 90 days (16.1% vs 19.2%, OR 0.81, 95% CrI 0.66 to 0.99, p=0.024). The frequency of symptomatic intracranial haemorrhage was similar between thrombectomy (4.2%) and control (4.0%) (OR 1.12, 95% CrI 0.76 to 1.68, p=0.72).

CONCLUSIONS

In patients with an acute anterior circulation stroke, modern device thrombectomy significantly reduces death and subsequent disability. The magnitude of these effects suggests that universal access to this treatment strategy should be the standard of care.

Outcomes of endovascular treatment for acute ischaemic stroke in Mater Dei Hospital, Malta

INTRODUCTION

The aim of this study was to assess the outcomes of endovascular treatment for acute ischaemic stroke in Mater Dei Hospital, Malta and compare them with international data.

METHODS

A prospective review of all patients who underwent mechanical thrombectomy from 2015 to the end of 2019 was performed. Eligible patients had large vessel occlusion confirmed on computed tomography angiography. Demographical data, the National Institutes of Health stroke scale at presentation, endovascular procedure details and process times were analysed. The thrombolysis in cerebral infarction score was used to assess the degree of reperfusion. A thrombolysis in cerebral infarction score of 2b-3 was considered as successful recanalisation. Functional outcome (modified Rankin scale score) and mortality at 90 days were measured. Functional independence was defined as a modified Rankin scale score of 2 or less.

RESULTS

A total of 132 patients underwent endovascular treatment, one patient was excluded due to incomplete data. The mean age was 71 (range 25-94) years, and the mean National Institutes of Health stroke scale at presentation was 14. Of the 131 patients treated, 69 received intravenous thrombolysis. Successful recanalisation (thrombolysis in cerebral infarction score 2b-3) was achieved in 80% of patients (105/131); 53% of patients (69/131) achieved functional independence at 90 days, with a mortality of 21% at 90 days. Symptomatic intracranial haemorrhage was recorded in 16 patients (12%) There was a statistical difference in the functional independence and mortality rate in favour of the successful recanalisation group.

CONCLUSION

Our data are consistent with a favourable clinical outcome after successful recanalisation. Service in Malta is achieving favourable outcomes for patients treated with mechanical thrombectomy for acute ischaemic stroke.

Clinical Imaging of the Penumbra in Ischemic Stroke: From the Concept to the Era of Mechanical Thrombectomy

The ischemic penumbra is defined as the severely hypoperfused, functionally impaired, at-risk but not yet infarcted tissue that will be progressively recruited into the infarct core. Early reperfusion aims to save the ischemic penumbra by preventing infarct core expansion and is the mainstay of acute ischemic stroke therapy. Intravenous thrombolysis and mechanical thrombectomy for selected patients with large vessel occlusion has been shown to improve functional outcome. Given the varying speed of infarct core progression among individuals, a therapeutic window tailored to each patient has recently been proposed. Recent studies have demonstrated that reperfusion therapies are beneficial in patients with a persistent ischemic penumbra, beyond conventional time windows. As a result, mapping the penumbra has become crucial in emergency settings for guiding personalized therapy. The penumbra was first characterized as an area with a reduced cerebral blood flow, increased oxygen extraction fraction and preserved cerebral metabolic rate of oxygen using positron emission tomography (PET) with radiolabeled O₂. Because this imaging method is not feasible in an acute clinical setting, the magnetic resonance imaging (MRI) mismatch between perfusion-weighted imaging and diffusion-weighted imaging, as well as computed tomography perfusion have been proposed as surrogate markers to identify the penumbra in acute ischemic stroke patients. Transversal studies comparing PET and MRI or using longitudinal assessment of a limited sample of patients have been used to define perfusion thresholds. However, in the era of mechanical thrombectomy, these thresholds are debatable. Using various MRI methods, the original penumbra definition has recently gained a significant interest. The aim of this review is to provide an overview of the evolution of the ischemic penumbra imaging methods, including their respective strengths and limitations, as well as to map the current intellectual structure of the field using bibliometric analysis and explore future directions.

Stentrievers : An engineering review

The advent of endovascular therapy for acute large vessel occlusion has revolutionized stroke treatment. Timely access to endovascular therapy, and the ability to restore intracranial flow in a safe, efficient, and efficacious manner has been critical to the success of the thrombectomy procedure. The stentriever has been a mainstay of endovascular stroke therapy, and current guidelines recommend the usage of stentrievers in the treatment of large vessel occlusion stroke. Despite the success of existing stentrievers, there continues to be significant development in the field, with newer stentrievers attempting to improve on each of the three key aspects of the thrombectomy procedure. Here, we elucidate the technical requirements that a stentriever must fulfill. We then review the basic variables of stent design, including the raw material and its form, fabrication method, geometric configuration, and further additions. Lastly, a selection of stentrievers from successive generations are reviewed using these engineering parameters, and clinical data is presented. Further avenues of stentriever development and testing are also presented.

Endovascular thrombectomy for acute ischemic stroke

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

Thrombectomy for acute large vessel occlusion in posterior and anterior circulation: a single institutional retrospective observational study

PURPOSE

Thrombectomy has been the gold standard therapy for anterior circulation occlusion; however, studies regarding thrombectomy in posterior circulation are lacking. In this study, we compared the efficiency of thrombectomy for acute large vessel occlusion between the posterior and anterior circulation at a single institution.

METHODS

We retrospectively analyzed consecutive patients who underwent thrombectomy for acute large vessel occlusion at our institution between August 2014 and April 2021. Differences in the clinical background, time course, and treatment technique and outcomes were evaluated between anterior and posterior circulation occlusions.

RESULTS

Overall, 353 patients (225 men and 128 women) were included: 314 patients had anterior circulation occlusion and 39 patients had posterior circulation occlusion. Between the patients with anterior and posterior circulation occlusions, the National Institutes of Health Stroke Scale (NIHSS) score (16 [12-21] vs. 29 [19-34], respectively, p < 0.001), door-to-puncture time (65 [45-99] vs. 99 [51-121] min, respectively, p = 0.018), and mortality (22 [7%] vs. 8 [20.5%] patients, respectively, p = 0.010) were significantly different; however, favorable outcome was not significantly different.

CONCLUSION

Higher NIHSS score, delayed treatment, and higher mortality were observed in posterior circulation occlusion than in anterior circulation occlusion; successful reperfusion and favorable outcomes were similar between them. Similar favorable outcomes and reperfusion ratio to the anterior circulation might be achieved also in the posterior circulation; however, delayed treatment and the optimal first-pass strategy might need further improvement.

Identifying clot composition using intravascular diffuse reflectance spectroscopy in a porcine model of endovascular thrombectomy

BACKGROUND

Endovascular thrombectomy has revolutionized the management of acute ischemic stroke and proven superior to stand-alone intravenous thrombolysis for large vessel occlusions. However, failed or delayed revascularization may occur as a result of a mismatch between removal technique and clot composition. Determination of clot composition before thrombectomy provides the possibility to adapt the technique to improve clot removal efficacy. We evaluated the application of diffuse reflectance spectroscopy (DRS) for intravascular determination of clot composition in vivo.

METHODS

Three clot types, enriched in red blood cells or fibrin or with a mixed content, were prepared from porcine blood and injected into the external carotids of a domestic pig. A guidewire-like DRS probe was used to investigate the optical spectra of clots, blood and vessel wall. Measurement positions were confirmed with angiography. Spectra were analyzed by fitting an optical model to derive physiological parameters. To evaluate the method's accuracy, photon scattering and blood and methemoglobin contents were included in a decision tree model and a random forest classification.

RESULTS

DRS could differentiate between the three different clot types, blood and vessel wall in vivo (p<0.0001). The sensitivity and specificity for detection was 73.8% and 98.8% for red blood cell clots, 80.6% and 97.8% for fibrin clots, and 100% and 100% for mixed clots, respectively.

CONCLUSION

Intravascular DRS applied via a custom guidewire can be used for reliable determination of clot composition in vivo. This novel approach has the potential to increase efficacy of thrombectomy procedures in ischemic stroke.

Midline Shift Greater than 3 mm Independently Predicts Outcome After Ischemic Stroke

BACKGROUND

Cerebral edema is associated with worse outcome after acute stroke; however, the minimum clinically relevant threshold remains unknown. This study aimed to identify the minimal degree of midline shift (MLS) that predicts outcome in a cohort encompassing a broad range of patients with acute stroke.

METHODS

Patient-level data from six acute stroke clinical trials were combined with endovascular thrombectomy registries from two academic referral centers, generating a combined cohort of 1977 patients. MLS was extracted from the original trial data or measured on computed tomography or magnetic resonance imaging that was obtained a median of 47.0 h (interquartile range 27.0-75.1 h) after stroke onset. Logistic regression was performed to identify predictors of poor outcome and the minimal clinically relevant MLS threshold.

RESULTS

The presence of MLS was a predictor of poor outcome, independent of baseline clinical and demographic factors (adjusted odds ratio 4.46, 95% confidence interval 3.56-5.59, p < 0.001). Examining the full range of MLS values identified, a value of greater than 3 mm was the critical threshold that significantly predicted poor outcome (adjusted odds ratio 3.20 [1.31-7.82], p = 0.011).

CONCLUSIONS

These results show that the presence of MLS predicts poor outcome and, specifically, MLS value greater than 3 mm is an important threshold across a variety of clinical settings. These findings may have relevance for the design and interpretation of future trials for antiedema therapies.

Cost-Consequence Analysis of Advanced Imaging in Acute Ischemic Stroke Care

Introduction: The purpose of this study was to illustrate the potential costs and health consequences of implementing advanced CT angiography and perfusion (CTAP) as the initial imaging in patients presenting with acute ischemic stroke (AIS) symptoms at a comprehensive stroke center (CSC).

Methods: A decision-simulation model based on the American Heart Association's recommendations for AIS care pathways was developed to assess imaging strategies for a 5-year period from the institutional perspective. The following strategies were compared: (1) advanced CTAP imaging: NCCT + CTA + CT perfusion at the time of presentation; (2) standard-of-care: non-contrast CT (NCCT) at the time of presentation, with CT angiography (CTA) ± CT perfusion only in select patients (initial imaging to exclude hemorrhage and extensive ischemia) for mechanical thrombectomy (MT) evaluation. Model parameters were defined with evidence-based data. Cost-consequence and sensitivity analyses were performed. The modified Rankin Scale (mRS) at 90 days was used as the outcome measure.

Results: The decision-simulation modeling revealed that adoption of the advanced CTAP imaging increased per-patient imaging costs by 1.19% ($9.28/$779.72), increased per-patient treatment costs by 33.25% ($729.96/$2,195.24), and decreased other per-patient acute care costs by 0.7% (–$114.12/$16,285.85). The large increase in treatment costs was caused by higher proportion of patients being treated. However, improved outcomes lowered the other per-patient acute care costs. Over the five-year period, advanced CTAP imaging led to 1.63% (66/4,040) more patients with good outcomes (90-day mRS 0-2), 2.23% (66/2,960) fewer patients with poor outcomes (90-day mRS 3-5), and no change in mortality (90-day mRS 6). Our CT equipment utilization analysis showed that the demand for CT equipment in terms of scanner time (minutes) was 24% lower in the advanced CTAP imaging strategy compared to the standard-of-care strategy. The number of EVT procedures performed at the CSC may increase by 50%.

Conclusions: Our study reveals that adoption of advanced CTAP imaging at presentation increases the demand for treatment of acute ischemic stroke patients as more patients are diagnosed within the treatment time window compared to standard-of-care imaging. Advanced imaging also leads to more patients with good functional outcomes and fewer patients with dependent functional status.

Value of pre-intervention CT perfusion imaging in acute ischemic stroke prognosis

Noninvasive imaging plays an important role in acute stroke towards diagnosis and ongoing management of patients. Systemic thrombolysis and endovascular thrombectomy (EVT) are proven treatments currently used in standards of care in acute stroke settings. The role of computed tomography angiography (CTA) in selecting patients with large vessel occlusion for EVT is well established. However, the value of CT perfusion (CTP) imaging in predicting outcomes after stroke remains ambiguous. This article critically evaluates the value of multimodal CT imaging in early diagnosis and prognosis of acute ischemic stroke with a focus on the role of CTP in delineating tissue characteristics, patient selection, and outcomes after reperfusion therapy. Insights on various technical and clinical considerations relevant to CTP applications in acute ischemic stroke, recommendations for existing workflow, and future areas of research are discussed.

Time-Based Decision Making for Reperfusion in Acute Ischemic Stroke

Decision making in the extended time windows for acute ischemic stroke can be a complex and time-consuming process. The process of making the clinical decision to treat has been compounded by the availability of different imaging modalities. In the setting of acute ischemic stroke, time is of the essence and chances of a good outcome diminish by each passing minute. Navigating the plethora of advanced imaging modalities means that treatment in some cases can be inefficaciously delayed. Time delays and individually based non-programmed decision making can prove challenging for clinicians. Visual aids can assist such decision making aimed at simplifying the use of advanced imaging. Flow charts are one such visual tool that can expedite treatment in this setting. A systematic review of existing literature around imaging modalities based on site of occlusion and time from onset can be used to aid decision making; a more program-based thought process. The use of an acute reperfusion flow chart helping navigate the myriad of imaging modalities can aid the effective treatment of patients.

Perfusion Imaging Predicts Favorable Outcomes after Basilar Artery Thrombectomy

OBJECTIVE

Perfusion imaging identifies anterior circulation stroke patients who respond favorably to endovascular thrombectomy (ET), but its role in basilar artery occlusion (BAO) is unknown. We hypothesized that BAO patients with limited regions of severe hypoperfusion (time to reach maximum concentration in seconds [Tmax] > 10) would have a favorable response to ET compared to patients with more extensive regions involved.

METHODS

We performed a multicenter retrospective cohort study of BAO patients with perfusion imaging prior to ET. We prespecified a Critical Area Perfusion Score (CAPS; 0-6 points), which quantified severe hypoperfusion (Tmax > 10) in cerebellum (1 point/hemisphere), pons (2 points), and midbrain and/or thalamus (2 points). Patients were dichotomized into favorable (CAPS ≤ 3) and unfavorable (CAPS > 3) groups. The primary outcome was a favorable functional outcome 90 days after ET (modified Rankin Scale = 0-3).

RESULTS

One hundred three patients were included. CAPS ≤ 3 patients (87%) had a lower median National Institutes of Health Stroke Scale score (NIHSS; 12.5, interquartile range [IQR] = 7-22) compared to CAPS > 3 patients (13%; 23, IQR = 19-36; p = 0.01). Reperfusion was achieved in 84% of all patients, with no difference between CAPS groups (p = 0.42). Sixty-four percent of reperfused CAPS ≤ 3 patients had a favorable outcome compared to 8% of nonreperfused CAPS ≤ 3 patients (odds ratio [OR] = 21.0, 95% confidence interval [CI] = 2.6-170; p < 0.001). No CAPS > 3 patients had a favorable outcome, regardless of reperfusion. In a multivariate regression analysis, CAPS ≤ 3 was a robust independent predictor of favorable outcome after adjustment for reperfusion, age, and pre-ET NIHSS (OR = 39.25, 95% CI = 1.34->999, p = 0.04).

INTERPRETATION

BAO patients with limited regions of severe hypoperfusion had a favorable response to reperfusion following ET. However, patients with more extensive regions of hypoperfusion in critical brain regions did not benefit from endovascular reperfusion. ANN NEUROL 2021.

Indications for Mechanical Thrombectomy for Acute Ischemic Stroke: Current Guidelines and Beyond

PURPOSE OF THE REVIEW

This article reviews recent breakthroughs in the treatment of acute ischemic stroke, mainly focusing on the evolution of endovascular thrombectomy, its impact on guidelines, and the need for and implications of next-generation randomized controlled trials.

RECENT FINDINGS

Endovascular thrombectomy is a powerful tool to treat large vessel occlusion strokes and multiple trials over the past 5 years have established its safety and efficacy in the treatment of anterior circulation large vessel occlusion strokes up to 24 hours from stroke onset.

SUMMARY

In 2015, multiple landmark trials (MR CLEAN, ESCAPE, SWIFT PRIME, REVASCAT, and EXTEND IA) established the superiority of endovascular thrombectomy over medical management for the treatment of anterior circulation large vessel occlusion strokes. Endovascular thrombectomy has a strong treatment effect with a number needed to treat ranging from 3 to 10. These trials selected patients based on occlusion location (proximal anterior occlusion: internal carotid or middle cerebral artery), time from stroke onset (early window: up to 6-12 hours), and acceptable infarct burden (Alberta Stroke Program Early CT Score [ASPECTS] ≥6 or infarct volume <50 mL). In 2017, the DAWN and DEFUSE-3 trials successfully extended the time window up to 24 hours in appropriately selected patients. Societal and national thrombectomy guidelines have incorporated these findings and offer Class 1A recommendation to a subset of well-selected patients. Thrombectomy ineligible stroke subpopulations are being studied in ongoing randomized controlled trials. These trials, built on encouraging data from pooled analysis of early trials (HERMES collaboration) and emerging retrospective data, are studying large vessel occlusion strokes with mild deficits (National Institutes of Health Stroke Scale <6) and large infarct burden (core volume >70 mL).

Biomarkers of Technical Success After Embolectomy for Acute Stroke

PURPOSE OF THE REVIEW

Stent retrievers and large-bore aspiration catheters have doubled substantial reperfusion rates compared to first-generation devices. This has been accompanied by a 3-fold reduction in procedural time to revascularization. To measure future thrombectomy improvements, new benchmarks for technical efficacy are needed. This review summarizes the recent literature concerning biomarkers of procedural success and harm and highlights future directions.

RECENT FINDINGS

Expanded Treatment in Cerebral Ischemia (eTICI), which incorporates scores for greater levels of reperfusion, improves outcome prediction. Core laboratory-adjudicated studies show that outcomes following eTICI 2c (90%-99% reperfusion) are superior to eTICI 2b50 and nearly equivalent to eTICI 3. Moreover, eTICI 2c improves scale reliability. Studies also confirm the importance of rapid revascularization, whether measured as first pass effect or procedural duration under 30 minutes. Distal embolization is a complication that impedes the extent and speed of revascularization, but few studies have reported its per-pass occurrence. Distal embolization and emboli to new territory should be measured after each thrombectomy maneuver. Collaterals have been shown to be an important modifier of thrombectomy benefit. A drawback of the currently accepted collateral grading scale is that it does not discriminate among the broad spectrum of partial collateralization. Important questions that require investigation include reasons for failed revascularization, the utility of a global Treatment in Cerebral Ischemia scale, and the optimal grading system for vertebrobasilar occlusions.

SUMMARY

Emerging data support a lead technical efficacy endpoint that combines the extent and speed of reperfusion. Efforts are needed to better characterize angiographic measures of treatment harm and of collateralization.

Clinical and Non-Clinical Determinants of the Effect of Mechanical Thrombectomy and Post-Stroke Functional Status of Patients in Short and Long-Term Follow-Up

To date, inconsistent results evaluating the effect of parameters on mechanical thrombectomy (MT) outcomes in stroke-patients have been published. This study aimed to identify the key parameters for functional status after MT in stroke-patients in short and long-term follow-up.

METHOD

The study analysis focused on the relevance of selected clinical and non-clinical parameters to the functional status of the patients after MT.

RESULTS

417 stroke-patients (mean age 67.8 ± 13.2 years) were qualified. Atrial fibrillation, and leukocytosis were significant for the neurological status on the first day of stroke (p = 0.036, and p = 0.0004, respectively). The parameters with the strongest effect on the functional status on day 10 were: age (p = 0.009), NIHSS (p = 0.002), hyperglycemia (p = 0.009), the result in TICI (p = 0.046), and first pass effect (p = 0.043). The parameters with the strongest effect on the functional status on day 365 were: age and NIHSS on the first day of stroke (p = 0.0002 and 0.002, respectively). Leukocytosis and the neurological status at baseline were key parameters associated with ICB after MT (p = 0.007 and p = 0.003, respectively).

CONCLUSIONS

Age and neurological status in the ultra-acute phase of stroke are crucial for the functional status in short and long-term observations of patients treated with mechanical thrombectomy. Atrial fibrillation, hyperglycemia, and inflammatory state are relevant to the short-term post-stroke functional status. First pass effect and the degree of post-interventional reperfusion are important technical parameters to the short-term functional status. Neurological status and white blood count during the acute phase are associated with a high rate of post-procedural intracranial bleeding.

The effectiveness of systemic and endovascular intra-arterial thrombectomy protocol for decreasing door-to-recanalization time duration

Objective

Variable treatment strategies and protocols have been applied to reduce time durations in the process of acute stroke management. The aim of this study is to investigate the effectiveness of our intra-arterial thrombectomy (IAT) protocol for decreasing door-to-recanalization time duration and improve successful recanalization.

Methods

A systemic and endovascular protocol included door-to-image, image-to-puncture and puncture-to-recanalization. We retrospectively analyzed the patients of pre- (Sep 2012–Apr 2014) and post-IAT protocol (May 2014–Jul 2018). Univariate analysis was used for the statistical significance according to variable factors (age, gender, the location of occluded vessel, successful recanalization TICI 2b-3). Independent t-test was used to compare the time duration.

Results

Among all 267 patients with acute stroke of anterior circulation, there were 50 and 217 patients with pre- and post-IAT protocol. Age, gender, and the location of occluded vessel have no statistical significance (p＞0.05). In pre- and post-IAT group, successful recanalization was 39 of 50 (78.0%) and 185/217 (85.3%), respectively (p＜0.05). Post-IAT (48.8%, 106/217) group had a higher tendency of good outcome than pre-IAT group (36.0%, 18/50) (p＞0.05). Pre- and post-IAT group showed 61.7±21.4 vs. 25±16.0 (p＜0.05), 102.0±29.8 vs. 82.7±30.4 (min) (p＜0.05), and 79.1±47.5 vs. 58.4±75.3 (p＜0.05) in three steps, respectively.

Conclusions

We suggest that the application of systemic and endovascular IAT protocols showed a significant time reduction for faster recanalization in patients with LVO. To build-up the well-designed IAT protocol through puncture-to-recanalization can be needed to decrease time duration and improve clinical outcome in recanalization therapy in acute stroke patients.

Adjunctive cytoprotective therapies in acute ischemic stroke: a systematic review

With the introduction of endovascular thrombectomy (EVT), a new era for treatment of acute ischemic stroke (AIS) has arrived. However, despite the much larger recanalization rate as compared to thrombolysis alone, final outcome remains far from ideal. This raises the question if some of the previously tested neuroprotective drugs warrant re-evaluation, since these compounds were all tested in studies where large-vessel recanalization was rarely achieved in the acute phase. This review provides an overview of compounds tested in clinical AIS trials and gives insight into which of these drugs warrant a re-evaluation as an add-on therapy for AIS in the era of EVT. A literature search was performed using the search terms "ischemic stroke brain" in title/abstract, and additional filters. After exclusion of papers using pre-defined selection criteria, a total of 89 trials were eligible for review which reported on 56 unique compounds. Trial compounds were divided into 6 categories based on their perceived mode of action: systemic haemodynamics, excitotoxicity, neuro-inflammation, blood-brain barrier and vasogenic edema, oxidative and nitrosative stress, neurogenesis/-regeneration and -recovery. Main trial outcomes and safety issues are summarized and promising compounds for re-evaluation are highlighted. Looking at group effect, drugs intervening with oxidative and nitrosative stress and neurogenesis/-regeneration and -recovery appear to have a favourable safety profile and show the most promising results regarding efficacy. Finally, possible theories behind individual and group effects are discussed and recommendation for promising treatment strategies are described.

Regional Disparity of Reperfusion Therapy for Acute Ischemic Stroke in Japan: A Retrospective Analysis of Nationwide Claims Data from 2010 to 2015

Background

We aimed to determine whether a regional disparity exists in usage of reperfusion therapy (intravenous recombinant tissue plasminogen activator [IV rt‐PA] and endovascular thrombectomy [EVT]) and post‐reperfusion 30‐day mortality in patients with acute ischemic stroke, and which regional factors are associated with their usage.

Methods and Results

We retrospectively investigated 69 948 patients (mean age±SD, 74.9±12.0 years; women, 41.4%) with acute ischemic stroke treated with reperfusion therapy between April 2010 and March 2016 in Japan using nationwide claims data. Regional disparity was evaluated using Gini coefficients for age‐ and sex‐adjusted usage of reperfusion therapy and 30‐day post‐reperfusion in‐hospital death ratio in 47 administrative regions. The association between regional factors and reperfusion therapy usage was evaluated with fixed‐effects regression models. During the study period, Gini coefficients showed low inequality (0.11–0.15) for use of IV rt‐PA monotherapy and IV rt‐PA and/or EVT and extreme inequality (0.49) for EVT usage in 2010, which became moderate inequality (0.25) by 2015. The densities of stroke centers and endovascular specialists, as well as market concentration, were associated with increased usage of reperfusion therapy whereas the proportion of rural residents and delayed ambulance transport were negatively associated with usage. Inequality in the standardized death ratio after EVT was extreme (0.86) in 2010 but became moderate (0.29) by 2015; inequality was low to moderate (0.17–0.23) for IV rt‐PA monotherapy and IV rt‐PA and/or EVT.

Conclusions

Scrutinizing existing data sources revealed regional disparity in reperfusion therapy for acute ischemic stroke and its associated regional factors in Japan.

Overview of Acute Ischemic Stroke Evaluation and Management

Stroke is a major contributor to death and disability worldwide. Prior to modern therapy, post-stroke mortality was approximately 10% in the acute period, with nearly one-half of the patients developing moderate-to-severe disability. The most fundamental aspect of acute stroke management is "time is brain". In acute ischemic stroke, the primary therapeutic goal of reperfusion therapy, including intravenous recombinant tissue plasminogen activator (IV TPA) and/or endovascular thrombectomy, is the rapid restoration of cerebral blood flow to the salvageable ischemic brain tissue at risk for cerebral infarction. Several landmark endovascular thrombectomy trials were found to be of benefit in select patients with acute stroke caused by occlusion of the proximal anterior circulation, which has led to a paradigm shift in the management of acute ischemic strokes. In this modern era of acute stroke care, more patients will survive with varying degrees of disability post-stroke. A comprehensive stroke rehabilitation program is critical to optimize post-stroke outcomes. Understanding the natural history of stroke recovery, and adapting a multidisciplinary approach, will lead to improved chances for successful rehabilitation. In this article, we provide an overview on the evaluation and the current advances in the management of acute ischemic stroke, starting in the prehospital setting and in the emergency department, followed by post-acute stroke hospital management and rehabilitation.

Endovascular Therapy for Stroke due to Basilar Artery Occlusion: A BASIC Challenge at BEST

Basilar artery occlusion stroke is known to have poor outcome with a high rate of morbidity and mortality despite best medical therapy. Since the original report of intra-arterial therapy for basilar artery occlusion in 1983, two recent randomized trials comparing endovascular therapy versus best medical management were completed on a large scale, BASICS (Basilar Artery International Cooperation Study) and the BEST trial (Basilar Artery Occlusion Endovascular Intervention Versus Standard Medical Treatment), both of which demonstrated equivocal benefit of the two modalities. In this commentary, we comment and highlight important lessons related to basilar occlusion stroke as learned from the BASICS and BEST randomized trials.

Multiple-Factor Analyses of Futile Recanalization in Acute Ischemic Stroke Patients Treated With Mechanical Thrombectomy

Background and Purpose: Acute ischemic stroke (AIS) is a serious threat to the life and health of middle-aged and elderly people. Mechanical thrombectomy offers the advantages of rapid recanalization, but the response of patients to this treatment varies greatly. This study investigated the risk factors for futile recanalization in AIS patients after thrombectomy through multivariate analyses. Methods: A retrospective study was conducted in AIS patients with anterior circulation occlusion from a derivation cohort and a validation cohort who underwent thrombectomy and reperfusion defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score of 2b/3. Using the modified Rankin Scale (mRS) at 90 days after the operation, the patients were divided into two groups, the meaningful recanalization group (mRS ≤ 2), and the futile recanalization group (mRS > 2). Multivariate logistic regression analyses were performed, and the receiver operating characteristic (ROC) curve was used to construct a risk prediction model for futile recanalization. The performance of prediction model was evaluated on the validation cohort. Results: A total of 140 patients in the derivation cohort were enrolled, 46 patients in the meaningful recanalization group and 94 patients in the futile recanalization group. The two groups were significantly different in age, preoperative National Institute of Health Stroke Scale (NIHSS) score, and collateral circulation ASITN/SIR grade (P < 0.05). In multivariate regression analyses, patients' age ≥ 71, NIHSS ≥ 12, and ASITN/SIR ≤ 3 were risk factors for futile recanalization. Hence, an ANA (Age-NIHSS-ASITN/SIR) score scale consisting of age, NIHSS score, and ASITN/SIR grade factors can effectively predict the risk for futile recanalization (area under curve 0.75, 95% CI 0.67-0.83, specificity 67.4%, and sensitivity 73.4%). The proportion of patients with futile recanalization in ANA groups 0, 1, 2, and 3 were 21.05, 56.76, 79.03, and 90.91%, respectively. Furthermore, ANA score scale had also a good performance for predicting futile recanalization on the validation cohort. Conclusions: Old age, high baseline NIHSS, and poor collateral circulation are risk factors for futile recanalization in AIS patients treated with thrombectomy. An ANA score that considers age, NIHSS, and collateral ASITN/SIR can effectively predict the risk for futile recanalization. Further studies with a larger sample size are needed to validate the prognostic value of this combined score for futile recanalization.

Acute Reperfusion Therapies for Acute Ischemic Stroke

The field of acute stroke treatment has made tremendous progress in reducing the overall burden of disability. Understanding the pathophysiology of acute ischemic injury, neuroimaging to quantify the extent of penumbra and infarction, and acute stroke reperfusion therapies have together contributed to these advancements. In this review we highlight advancements in reperfusion therapies for acute ischemic stroke.

MR Perfusion in the Evaluation of Mechanical Thrombectomy Candidacy

ABSTRACT

Stroke is a leading cause of disability and mortality, and the incidence of ischemic stroke is projected to continue to rise in coming decades. These projections emphasize the need for improved imaging techniques for accurate diagnosis allowing effective treatments for ischemic stroke. Ischemic stroke is commonly evaluated with computed tomography (CT) or magnetic resonance imaging (MRI). Noncontrast CT is typically used within 4.5 hours of symptom onset to identify candidates for thrombolysis. Beyond this time window, thrombolytic therapy may lead to poor outcomes if patients are not optimally selected using appropriate imaging. MRI provides an accurate method for the earliest identification of core infarct, and MR perfusion can identify salvageable hypoperfused penumbra. The prognostic value for a better outcome in these patients lies in the ability to distinguish between core infarct and salvageable brain at risk-the ischemic penumbra-which is a function of the degree of ischemia and time. Many centers underutilize MRI for acute evaluation of ischemic stroke. This review will illustrate how perfusion-diffusion mismatch calculated from diffusion-weighted MRI and MR perfusion is a reliable approach for patient selection for stroke therapy and can be performed in timeframes that are comparable to CT-based algorithms while providing potentially superior diagnostic information.

Endovascular Thrombectomy Treatment: Beyond Early Time Windows and Small Core

ABSTRACT

Tremendous advancements in the treatment of acute ischemic stroke in the last 25 years have been based on the principle of reperfusion in early time windows and identification of small core infarct for intravenous thrombolysis and mechanical thrombectomy. Advances in neuroimaging have made possible the safe treatment of patients with acute ischemic stroke in longer time windows and with more specific selection of patients with salvageable brain tissue. In this review, we discuss the history of endovascular stroke thrombectomy trials and highlight the neuroimaging-based trials that validated mechanical thrombectomy techniques in the extended time window with assessment of penumbral tissue. We conclude with a survey of currently open trials that seek to safely expand eligibility for this highly efficacious treatment.

Trends in mechanical thrombectomy and decompressive hemicraniectomy for stroke: A multicenter study

BACKGROUND AND PURPOSE

Acute ischemic stroke has increasingly become a procedural disease following the demonstrated benefit of mechanical thrombectomy (MT) for emergent large vessel occlusion (ELVO) on clinical outcomes and tissue salvage in randomized trials. Given these data and anecdotal experience of decreased numbers of decompressive hemicraniectomies (DHCs) performed for malignant cerebral edema, we sought to correlate the numbers of strokes, thrombectomies, and DHCs performed over the timeline of the 2013 failed thrombolysis/thrombectomy trials, to the 2015 modern randomized MT trials, to post-DAWN and DEFUSE 3.

MATERIALS AND METHODS

This is a multicenter retrospective compilation of patients who presented with ELVO in 11 US high-volume comprehensive stroke centers. Rates of tissue plasminogen activator (tPA), thrombectomy, and DHC were determined by current procedural terminology code, and specificity to acute ischemic stroke confirmed by each institution. Endpoints included the incidence of stroke, thrombectomy, and DHC and rates of change over time.

RESULTS

Between 2013 and 2018, there were 55,247 stroke admissions across 11 participating centers. Of these, 6145 received tPA, 4122 underwent thrombectomy, and 662 patients underwent hemicraniectomy. The trajectories of procedure rates over time were modeled and there was a significant change in MT rate (p = 0.002) without a concomitant change in the total number of stroke admissions, tPA administration rate, or rate of DHC.

CONCLUSIONS

This real-world study confirms an increase in thrombectomy performed for ELVO while demonstrating stable rates of stroke admission, tPA administration and DHC. Unlike prior studies, increasing thrombectomy rates were not associated with decreased utilization of hemicraniectomy.

Trends in Reperfusion Therapy for In-Hospital Ischemic Stroke in the Endovascular Therapy Era

Importance

A significant proportion of acute ischemic strokes occur while patients are hospitalized. Limited contemporary data exist on the utilization rates of intravenous thrombolysis or endovascular therapy for in-hospital stroke.

Objective

To use a national registry to examine temporal trends in the use of intravenous and endovascular reperfusion therapies for treatment of in-hospital stroke.

Design, Setting, and Participants

This retrospective cohort study analyzed data from 267 956 patients who underwent reperfusion therapy for stroke with in-hospital or out-of-hospital onset reported in the Get With the Guidelines-Stroke national registry from January 2008 to September 2018.

Exposures

In-hospital onset vs out-of-hospital onset of stroke symptoms.

Main Outcomes and Measures

Temporal trends in the use of reperfusion therapy, process measures of quality, and the association between functional outcomes and key patient characteristics, comorbidities, and treatments.

Results

Of 67 493 patients with in-hospital stroke onset, this study observed increased rates of vascular risk factors (standardized mean difference >10%) but no significant differences in age or sex in patients undergoing intravenous thrombolysis only (mean [interquartile range {IQR}] age, 72 [80-62] y; 53.2% female) or those undergoing endovascular therapy (mean [IQR] age, 69 [59-79] y; 49.8% female). Of these patients, 10 481 (15.5%) received intravenous thrombolysis and 2494 (3.7%) underwent endovascular therapy. Compared with 2008, in 2018 the proportion of in-hospital stroke among all stroke hospital discharges was higher (3.5% vs 2.7%; P < .001), as was use of intravenous thrombolysis (19.1% vs 9.1%; P < .001) and endovascular therapy (6.4% vs 2.5%; P < .001) in patients with in-hospital stroke, with a significant increase in endovascular therapy in mid-2015 (P < .001). Compared with patients who received intravenous thrombolysis for out-of-hospital stroke onset, those with in-hospital onset were associated with longer median (IQR) times from stroke recognition to cranial imaging (33 [18-60] vs 16 [9-26] minutes; P < .001) and to thrombolysis bolus (81 [52-125] vs 60 [45-84] minutes; P < .001). In adjusted analyses, patients with in-hospital stroke onset who were treated with intravenous thrombolysis were less likely to ambulate independently at discharge (adjusted odds ratio, 0.78; 95% CI, 0.74-0.82; P < .001) and were more likely to die or to be discharged to hospice (adjusted odds ratio, 1.39; 95% CI, 1.29-1.50; P < .001) than patients with out-of-hospital onset who also received intravenous thrombolysis treatment. Comparisons among patients treated with endovascular therapy yielded similar findings.

Conclusions and Relevance

In this cohort study, in-hospital stroke onset was increasingly reported and treated with reperfusion therapy. Compared with out-of-hospital stroke onset, in-hospital onset was associated with longer delays to reperfusion and worse functional outcomes, highlighting opportunities to further care for patients with in-hospital stroke onset.

Endovascular thrombectomy and intra-arterial interventions for acute ischaemic stroke

BACKGROUND

Most disabling strokes are due to a blockage of a large artery in the brain by a blood clot. Prompt removal of the clot with intra-arterial thrombolytic drugs or mechanical devices, or both, can restore blood flow before major brain damage has occurred, leading to improved recovery. However, these so-called endovascular interventions can cause bleeding in the brain. This is a review of randomised controlled trials of endovascular thrombectomy or intra-arterial thrombolysis, or both, for acute ischaemic stroke.

OBJECTIVES

To assess whether endovascular thrombectomy or intra-arterial interventions, or both, plus medical treatment are superior to medical treatment alone in people with acute ischaemic stroke.

SEARCH METHODS

We searched the Trials Registers of the Cochrane Stroke Group and Cochrane Vascular Group (last searched 1 September 2020), CENTRAL (the Cochrane Library, 1 September 2020), MEDLINE (May 2010 to 1 September 2020), and Embase (May 2010 to 1 September 2020). We also searched trials registers, screened reference lists, and contacted researchers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of any endovascular intervention plus medical treatment compared with medical treatment alone in people with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors (MBR and MJ) applied the inclusion criteria, extracted data, and assessed trial quality. Two review authors (MBR and HL) assessed risk of bias, and the certainty of the evidence using GRADE. We obtained both published and unpublished data if available. Our primary outcome was favourable functional outcome at the end of the scheduled follow-up period, defined as a modified Rankin Scale score of 0 to 2. Eighteen trials (i.e. all but one included trial) reported their outcome at 90 days. Secondary outcomes were death from all causes at in the acute phase and by the end of follow-up, symptomatic intracranial haemorrhage in the acute phase and by the end of follow-up, neurological status at the end of follow-up, and degree of recanalisation.

MAIN RESULTS

We included 19 studies with a total of 3793 participants. The majority of participants had large artery occlusion in the anterior circulation, and were treated within six hours of symptom onset with endovascular thrombectomy. Treatment increased the chance of achieving a good functional outcome, defined as a modified Rankin Scale score of 0 to 2: risk ratio (RR) 1.50 (95% confidence interval (CI) 1.37 to 1.63; 3715 participants, 18 RCTs; high-certainty evidence). Treatment also reduced the risk of death at end of follow-up: RR 0.85 (95% CI 0.75 to 0.97; 3793 participants, 19 RCTs; high-certainty evidence) without increasing the risk of symptomatic intracranial haemorrhage in the acute phase: RR 1.46 (95% CI 0.91 to 2.36; 1559 participants, 6 RCTs; high-certainty evidence) or by end of follow-up: RR 1.05 (95% CI 0.72 to 1.52; 1752 participants, 10 RCTs; high-certainty evidence); however, the wide confidence intervals preclude any firm conclusion. Neurological recovery to National Institutes of Health Stroke Scale (NIHSS) score 0 to 1 and degree of recanalisation rates were better in the treatment group: RR 2.03 (95% CI 1.21 to 3.40; 334 participants, 3 RCTs; high-certainty evidence) and RR 3.11 (95% CI 2.18 to 4.42; 268 participants, 3 RCTs; high-certainty evidence), respectively.

AUTHORS' CONCLUSIONS

In individuals with acute ischaemic stroke due to large artery occlusion in the anterior circulation, endovascular thrombectomy can increase the chance of survival with a good functional outcome without increasing the risk of intracerebral haemorrhage or death.

Acute reperfusion therapies for acute ischemic stroke patients with unknown time of symptom onset or in extended time windows: an individualized approach

Recent randomized controlled clinical trials (RCTs) have revolutionized acute ischemic stroke care by extending the use of intravenous thrombolysis and endovascular reperfusion therapies in time windows that have been originally considered futile or even unsafe. Both systemic and endovascular reperfusion therapies have been shown to improve outcome in patients with wake-up strokes or symptom onset beyond 4.5 h for intravenous thrombolysis and beyond 6 h for endovascular treatment; however, they require advanced neuroimaging to select stroke patients safely. Experts have proposed simpler imaging algorithms but high-quality data on safety and efficacy are currently missing. RCTs used diverse imaging and clinical inclusion criteria for patient selection during the dawn of this novel stroke treatment paradigm. After taking into consideration the dismal prognosis of nonrecanalized ischemic stroke patients and the substantial clinical benefit of reperfusion therapies in selected late presenters, we propose rescue reperfusion therapies for acute ischemic stroke patients not fulfilling all clinical and imaging inclusion criteria as an option in a subgroup of patients with clinical and radiological profiles suggesting low risk for complications, notably hemorrhagic transformation as well as local or remote parenchymal hemorrhage. Incorporating new data to treatment algorithms may seem perplexing to stroke physicians, since treatment and imaging capabilities of each stroke center may dictate diverse treatment pathways. This narrative review will summarize current data that will assist clinicians in the selection of those late presenters that will most likely benefit from acute reperfusion therapies. Different treatment algorithms are provided according to available neuroimaging and endovascular treatment capabilities.

Sex Disparities in Enrollment in Recent Randomized Clinical Trials of Acute Stroke: A Meta-analysis

Importance

The underenrollment of women in randomized clinical trials represents a threat to the validity of the evidence supporting clinical guidelines and potential disparities in access to novel treatments.

Objective

To determine whether women were underenrolled in contemporary randomized clinical trials of acute stroke therapies published in 9 major journals after accounting for their representation in underlying stroke populations.

Data Sources

MEDLINE was searched for acute stroke therapeutic trials published between January 1, 2010, and June 11, 2020.

Study Selection

Eligible articles reported the results of a phase 2 or 3 randomized clinical trial that enrolled patients with stroke and/or transient ischemic attack and examined a therapeutic intervention initiated within 1 month of onset.

Data Extraction

Data extraction was performed by 2 independent authors in duplicate. Individual trials were matched to estimates of the proportion of women in underlying stroke populations using the Global Burden of Disease database.

Main Outcomes and Measures

The primary outcome was the enrollment disparity difference (EDD), the absolute difference between the proportion of trial participants who were women and the proportion of strokes in the underlying disease populations that occurred in women. Random-effects meta-analyses of the EDD were performed, and multivariable metaregression was used to explore the associations of trial eligibility criteria with disparity estimates.

Results

The search returned 1529 results, and 115 trials (7.5%) met inclusion criteria. Of 121 105 randomized patients for whom sex was reported, 52 522 (43.4%) were women. The random-effects summary EDD was -0.053 (95% CI, -0.065 to -0.040), indicating that women were underenrolled by 5.3 percentage points. This disparity persisted across virtually all geographic regions, intervention types, and stroke types, apart from subarachnoid hemorrhage (0.117 [95% CI, 0.084 to 0.150]). When subarachnoid hemorrhage trials were excluded, the summary EDD was -0.067 (95% CI, -0.078 to -0.057). In the multivariable metaregression analysis, an upper age limit of 80 years as an eligibility criterion was associated with a 6-percentage point decrease in the enrollment of women.

Conclusions and Relevance

Further research is needed to understand the causes of the underenrollment of women in acute stroke trials. However, to maximize representation, investigators should avoid imposing age limits on enrollment.