Thrombectomy 6-24 hours after stroke in trial ineligible patients

Endovascular thrombectomy for DAWN- and DEFUSE-3 ineligible acute ischemic stroke patients: a systematic review and meta-analysis

BACKGROUND

Endovascular therapy (EVT) has been proven beneficial for treating acute ischemic strokes (AIS) with large vessel occlusion (LVO). Recent trials of DAWN and DEFUSE-3 have extended the treatment window to 6-24 h, sparking investigations into EVT outcomes for patients not eligible for DAWN/DEFUSE-3 criteria.

PURPOSE

To assess the outcomes of endovascular therapy (EVT) for late-window anterior circulation large vessel occlusion (LVO) in acute ischemic stroke patients, comparing DAWN/DEFUSE-3 eligible (DD) and ineligible (NDND) groups.

METHODS

This systematic review and meta-analysis examined EVT outcomes for patients with late-window anterior circulation LVO beyond 6 h. We categorized patients as DAWN/DEFUSE-3 eligible (DD) and ineligible (NDND). Our search covered PubMed, Embase, Web of Science, and Scopus. A total of 464 records were initially identified. After duplicate removal, 298 studies were screened. Nine studies were included and analyzed. Our analysis focused on study characteristics, baseline comparisons, risk of bias, and outcomes.

RESULTS

Baseline characteristics showed comparable age, gender, most comorbidities, NIHSS score, and ASPECTS between DAWN/DEFUSE-3 eligible (DD) and ineligible (NDND) patients. NDND patients' history showed a higher rate of atrial fibrillation and larger infarct volumes on baseline imaging. Successful reperfusion rates (TICI 2b-3) were similar between DD and NDND with 354 out of 469 in the DD group and 364 out of 459 in the NDND group (OR = 0.86; 95% CI 0.40, 1.84; p = 0.689), though with significant heterogeneity (I2 = 73%; P = 0.002). The proportion of patients with distal occlusions was significantly higher in the NDND group as compared to the DD group (137 (39.4%) of 347 patients versus 47 (11%) of 428 patients, respectively), with significant heterogeneity across studies (I2 = 85%, p = 0.023). Functional independence at 90 days (mRS 0-2) showed no significant difference between groups with 259 out of 802 in the DD group and 197 out of 668 in the NDND group (OR = 1.12; 95% CI 0.77, 1.63; p = 0.552) but also exhibited notable heterogeneity (I2 = 46%, p = 0.063). Symptomatic intracranial hemorrhage (sICH) rates were lower in DD with 14 out of 309 in the DD group and 47 out of 400 in NDND group (OR = 0.49; 95% CI 0.25, 0.93; p = 0.029) as compared to the NDND patients, showing no heterogeneity (I2 = 0%, p = 0.552). 90-day mortality was lower in DD with 43 out of 304 in the DD group and 107 out of 399 in the NDND group (OR = 0.55; 95% CI 0.37, 0.82; p = 0.004) as compared to NDND patients, with no significant heterogeneity (I2 = 0%, p = 0.536).

CONCLUSION

This meta-analysis demonstrates equivalent rates of functional independence between DD and NDND patients. However, the high proportion of distal occlusions and higher rates of sICH and mortality in NDND patients suggest caution in offering mechanical thrombectomy to DAWN/DEFUSE-3 ineligible patients. A more flexible approach to EVT eligibility criteria could benefit select patients in real-world practice. Nonetheless, further research is needed to identify which patients would benefit from expanded EVT eligibility criteria.

Mechanical thrombectomy in patients with acute ischemic stroke in the USA before and after time window expansion

BACKGROUND

In 2018, the time window for mechanical thrombectomy eligibility in patients with acute ischemic stroke increased from within 6 hours to within 24 hours of symptom onset. The purpose of this study was to evaluate the effect of window expansion on procedural and hospital volumes and patient outcomes at a national level.

METHODS

We conducted a retrospective cohort study of patients with acute ischemic stroke undergoing mechanical thrombectomy using data from the National Inpatient Sample. We compared the numbers of mechanical thrombectomy procedures and performing hospitals between 2017 and 2019 in the USA, and the proportion of patients discharged home/self-care, those with in-hospital mortality and post-procedural intracranial hemorrhage (2019 vs 2017) after adjustment for potential confounders.

RESULTS

The number of patients with ischemic stroke who underwent mechanical thrombectomy increased from 16 960 in 2017 to 28 120 in 2019. There was an increase in the number of hospitals performing mechanical thrombectomy (501 in 2017, 585 in 2019) and those performing ≥50 procedures/year (97 in 2017, 199 in 2019; P<0.001). The odds of in-hospital mortality decreased (OR 0.79, 95% CI 0.66 to 0.94, P=0.008) and the odds of intracranial hemorrhage increased (OR 1.18, 95% CI 1.06 to 1.31, P=0.003) in 2019 compared with 2017, with no change in odds of discharge to home.

CONCLUSIONS

The window expansion for mechanical thrombectomy for patients with acute ischemic stroke was associated with an increase in the numbers of mechanical thrombectomy procedures and performing hospitals with a reduction of in-hospital mortality in the USA.

Simplified stroke imaging selection modality for endovascular thrombectomy in the extended time window: systematic review and meta-analysis

BACKGROUND

The impact of imaging selection modality on clinical outcomes of endovascular thrombectomy (EVT) in the 6-24-hour time window remains undetermined. We compared the clinical outcomes of a simplified stroke imaging selection modality using non-contrast computed tomography (NCCT)±CT angiography (CTA) with using advanced CT perfusion (CTP).

METHODS

PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception to 1 May 2022 to compare NCCT±CTA and CTP for patient selection for EVT in late-presenting stroke with large vessel occlusions (LVO). The primary outcome was the proportion of patients achieving functional independence (modified Rankin Scale score 0-2) within 180 days. The secondary outcomes included mortality within 90 days, successful recanalization, and any intracranial hemorrhage.

RESULTS

A total of 3419 patients in six articles were included in this meta-analysis. There was no significant difference between NCCT±CTA (no-CTP) and CTP in functional independence either in overall or subgroup analysis. However, the mortality in the no-CTP group was higher than in the CTP group. Furthermore, within the DAWN/DEFUSE 3-like subgroup, there were no significant differences in mortality, successful recanalization, and any intracranial hemorrhage between the two groups.

CONCLUSION

There was no significant difference between the simplified NCCT±CTA modality and the advanced CTP modality. The use of NCCT±CTA may represent a reasonable option for selecting patients for EVT in the extended time window, especially in the absence of CTP and acute phase MRI capabilities.

Advances in mechanical thrombectomy for acute ischaemic stroke

Mechanical thrombectomy is a ground breaking treatment for acute ischaemic stroke caused by occlusion of a large vessel. Its efficacy over intravenous thrombolysis has been proven in multiple trials with a lower number needed to treat than percutaneous coronary intervention for acute myocardial infarction. However, access to this key treatment modality remains limited with a considerable postcode lottery across the UK and many parts of the world. The evidence base for mechanical thrombectomy dates back to 2015. Since then, there have been important advances in establishing and widening the criteria for treatment. This narrative review aims to summarise the current evidence base and latest advances for physicians and academics with an interest in recanalisation treatments for acute ischaemic stroke.

Thrombectomy for Anterior Circulation Stroke in a Witnessed Late Time Window Versus Early Time Window

Introduction

Thrombectomy is the standard treatment for anterior circulation stroke due to large vessel occlusions in a late time window (6 to 24 hours) for patients selected based on perfusion imaging. Most patients treated in late time window studies presented as unwitnessed or wake-up strokes. Whether patients presenting with unwitnessed stroke have an actual time window greater than 6 hours is unclear. The aim of this study was to assess the outcomes of thrombectomy in the treatment of patients presenting with anterior circulation large vessel stroke in an actual late time window of more than 6 hours.

Methods

This single-center registry of thrombectomy in the treatment of stroke caused by anterior circulation large vessel occlusions (LVOs) included 430 patients treated between 2011 and 2019. Patients were divided into 2 groups: an early time window (≤ 6 hours) group and a late time window group (> 6 hours).

Results

Outcomes of the early and the late time window groups, respectively, were recanalization of 86.8% vs 82.7% (P = .29), symptomatic intracranial hemorrhage of 8.2% vs 5.7% (P = .40), good clinical outcome of 45.4% vs 41.3% (P = .46), and mortality of 20.2% vs 25% (P = .30) at 3 months.

Conclusions

Thrombectomy for anterior circulation large vessel occlusions after 6 hours of symptoms onset seems to be as safe and effective as the standard thrombectomy within 6 hours from symptoms onset, even without perfusion analysis. Randomized trials are needed to confirm these findings.

Association between time to treatment and clinical outcomes in endovascular thrombectomy beyond 6 hours without advanced imaging selection

BACKGROUND

The effectiveness and safety of endovascular thrombectomy (EVT) in the late window (6-24 hours) for acute ischemic stroke (AIS) patients selected without advanced imaging is undetermined. We aimed to assess clinical outcomes and the relationship with time-to-EVT treatment beyond 6 hours of stroke onset without advanced neuroimaging.

METHODS

Patients who underwent EVT selected with non-contrast CT/CT angiography (without CT perfusion or MR imaging), between October 2015 and March 2020, were included from a national stroke registry. Functional and safety outcomes were assessed in both early (<6 hours) and late windows with time analyzed as a continuous variable.

RESULTS

Among 3278 patients, 2610 (79.6%) and 668 (20.4%) patients were included in the early and late windows, respectively. In the late window, for every hour delay, there was no significant association with shift towards poorer functional outcome (modified Rankin Scale (mRS)) at discharge (adjusted common OR 0.98, 95% CI 0.94 to 1.01, p=0.27) or change in predicted functional independence (mRS ≤2) (24.5% to 23.3% from 6 to 24 hours; aOR 0.99, 95% CI0.94 to 1.04, p=0.85). In contrast, predicted functional independence was time sensitive in the early window: 5.2% reduction per-hour delay (49.4% to 23.5% from 1 to 6 hours, p=0.0001). There were similar rates of symptomatic intracranial hemorrhage (sICH) (3.4% vs 4.6%, p=0.54) and in-hospital mortality (12.9% vs 14.6%, p=0.33) in the early and late windows, respectively, without a significant association with time.

CONCLUSION

In this real-world study, there was minimal change in functional disability, sICH and in-hospital mortality within and across the late window. While confirmatory randomized trials are needed, these findings suggest that EVT remains feasible and safe when performed in AIS patients selected without advanced neuroimaging between 6-24 hours from stroke onset.

Mechanical Thrombectomy Versus Best Medical Treatment in the Late Time Window in Non-DEFUSE-Non-DAWN Patients: A Multicenter Cohort Study

BACKGROUND

We assessed the efficacy and safety of mechanical thrombectomy (MT) in adult stroke patients with anterior circulation large vessel occlusion presenting in the late time window not fulfilling the DEFUSE-3 (Thrombectomy for Stroke at 6 to 16 Hours With Selection by Perfusion Imaging trial) and DAWN (Thrombectomy 6 to 24 Hours After Stroke With a Mismatch Between Deficit and Infarct trial) inclusion criteria.

METHODS

Cohort study of adults with anterior circulation large vessel occlusion admitted between 6 and 24 hours after last-seen-well at 5 participating Swiss stroke centers between 2014 and 2021. Mismatch was assessed by computer tomography or magnetic resonance imaging perfusion with automated software (RAPID or OLEA). We excluded patients meeting DEFUSE-3 and DAWN inclusion criteria and compared those who underwent MT with those receiving best medical treatment alone by inverse probability of treatment weighting using the propensity score. The primary efficacy end point was a favorable functional outcome at 90 days, defined as a modified Rankin Scale score shift toward lower categories. The primary safety end point was symptomatic intracranial hemorrhage within 7 days of stroke onset; the secondary was all-cause mortality within 90 days.

RESULTS

Among 278 patients with anterior circulation large vessel occlusion presenting in the late time window, 190 (68%) did not meet the DEFUSE-3 and DAWN inclusion criteria and thus were included in the analyses. Of those, 102 (54%) received MT. In the inverse probability of treatment weighting analysis, patients in the MT group had higher odds of favorable outcomes compared with the best medical treatment alone group (modified Rankin Scale shift: acOR, 1.46 [1.02-2.10]; P=0.04) and lower odds of all-cause mortality within 90 days (aOR, 0.59 [0.37-0.93]; P=0.02). There were no significant differences in symptomatic intracranial hemorrhage (MT versus best medical treatment alone: 5% versus 2%, P=0.63).

CONCLUSIONS

Two out of 3 patients with anterior circulation large vessel occlusion presenting in the late time window did not meet the DEFUSE-3 and DAWN inclusion criteria. In these patients, MT was associated with higher odds of favorable functional outcomes without increased rates of symptomatic intracranial hemorrhage. These findings support the enrollment of patients into ongoing randomized trials on MT in the late window with more permissive inclusion criteria.

Neuroimaging of Acute Ischemic Stroke: Multimodal Imaging Approach for Acute Endovascular Therapy

Advances in acute ischemic stroke (AIS) treatment have been contingent on innovations in neuroimaging. Neuroimaging plays a pivotal role in the diagnosis and prognosis of ischemic stroke and large vessel occlusion, enabling triage decisions in the emergent care of the stroke patient. Current imaging protocols for acute stroke are dependent on the available resources and clinicians' preferences and experiences. In addition, differential application of neuroimaging in medical decision-making, and the rapidly growing evidence to support varying paradigms have outpaced guideline-based recommendations for selecting patients to receive intravenous or endovascular treatment. In this review, we aimed to discuss the various imaging modalities and approaches used in the diagnosis and treatment of AIS.

Does MRI add value in selecting patients for thrombectomy beyond the 6 h window? A matched-control analysis

Background

Controversy exists regarding the need of advanced imaging for patient selection in the extended window.

Aims

To analyze the effect of initial imaging modalities on clinical outcomes of patients underwent MT in the extended window.

Methods

This was a retrospective analysis of a prospective registry, the Endovascular Treatment Key Technique and Emergency Workflow Improvement of Acute Ischemic Stroke (ANGEL-ACT) registry which was conducted at 111 hospitals between November 2017 and March 2019 in China. Primary study cohort and Guideline like cohort were identified, in each cohort, two imaging modalities for patient selection in 6 to 24 h window were defined: (1) NCCT ± CTA, (2) MRI. Guideline-like cohort were further screened based on key features of the DAWN and DEFUSE 3 trials. The primary outcome was 90 day mRS. The safety outcomes were sICH, any ICH and 90-day mortality.

Results

After adjusting for covariates, there were no significant differences in 90 day mRS or any safety outcomes between two imaging modalities groups in both cohorts. All outcome measures of mixed-effects logistic regression model were consistent with propensity score matching model.

Conclusion

Our results indicate that patients presented with anterior large vessel occlusion in the extended time window can potentially benefit from MT even in the absence of MRI selection. This conclusion needs to be verified by the prospective randomized clinical trials.

Comparison between collateral status and DEFUSE 3 or DAWN criteria in patient selection for endovascular thrombectomy within 6-24 hours after stroke: a protocol for meta-analysis

INTRODUCTION

Perfusion imaging according to the DEFUSE 3 or DAWN criteria has been applied to select patients with large vascular occlusive stroke undergo endovascular therapy (EVT) in the extended time window. Emerging studies have shown that collateral blood flow-based criteria may be as effective as DEFUSE 3 and DAWN criteria for the evaluation of EVT eligibility beyond 6 hours. We will conduct a meta-analysis to compare collateral status-based criteria with DEFUSE 3 or DAWN criteria.

METHODS AND ANALYSIS

We will conduct a search for the studies comparing collateral blood flow-based imaging with CT perfusion using the DEFUSE 3 or DAWN criteria in selecting patients with acute ischaemic stroke undergo EVT in the Web of Science, PubMed, EMBASE and the Cochrane Library databases between November 2017 and November 2021. We will also search the sources of grey literature, the reference lists of included studies and the newly published studies during the review period. Two investigators will independently screen the eligible studies and extract data. The study quality will be assessed by using the Newcastle-Ottawa Scale or the Cochrane risk bias tool. Stata V.17 will be used to conduct data analysis.

ETHICS AND DISSEMINATION

Patient informed consent and ethics approval are not necessary as this study uses only published studies. The finding of this meta-analysis will be propagated through committee conferences or peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42021281928.

Diagnosis of Ischemic Stroke: As Simple as Possible

The absolute majority of strokes in high-income countries, roughly 91%, are of ischemic origin. This review is focused on acute ischemic stroke (AIS) with large vessel occlusion (LVO) in the anterior circulation, which is considered the most devastating subtype of AIS. Moreover, stroke survivors impose substantial direct and indirect costs of care as well as costs due to productivity loss. We review of diagnostic possibilities of individual imaging methods such as computed tomography and magnetic resonance imaging, and discuss their pros and cons in the imaging of AIS. The goals of non-invasive imaging in AIS are as follows: (a) to rule out intracranial hemorrhage and to quickly exclude hemorrhagic stroke and contraindications for intravenous thrombolysis; (b) to identify potential LVO and its localization and to quickly provide guidance for endovascular treatment; (c) to assess/estimate the volume or size of the ischemic core. We suggest fast diagnostic management, which is able to quickly satisfy the above-mentioned diagnostic goals in AIS with LVO.

Endovascular treatment for wake-up stroke and daytime unwitnessed stroke: A meta-analysis

BACKGROUND

Evidence from sources outside the typical clinical research setting, such as a real-world setting, may complement evidence from randomised controlled trials (RCTs). The aim of the present study was to carry out a meta-analysis of available real-world evidence that focused on the efficacy and safety of endovascular treatment in patients with wake-up stroke (WUS) or daytime unwitnessed stroke (DUS) compared to that in patients treated ≤ 6 h after the onset of an ischemic stroke.

METHODS

Data mining was conducted on 1 May 2021 from PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials Cochrane Library. The study reviewed all published that assessed the effect of endovascular treatment in WUS and DUS compared to that received by patients with ischemic stroke. Relevant data were extracted and the narrative was reviewed and analysed. The results were expressed as odds ratios (ORs) with 95% confidence intervals (CIs).

FINDINGS

The meta-analysis showed no significant differences between the two groups in the rates of functional independence (OR, 0.81; 95% CI, 0.65-1.02; P = 0.07), symptomatic intracerebral haemorrhage (OR, 0.86; 95% CI, 0.57-1.30; P = 0.470), and all-cause mortality (OR, 0.92; 95% CI, 0.73-1.16; P = 0.50). There was also no heterogeneity between the trials.

CONCLUSION

The pooled analysis provided evidence to support the use of endovascular treatment in WUS and DUS with favourable perfusion imaging. The meta-analysis confirmed the main findings of RCTs of endovascular treatment in WUS and DUS in a real-world setting and therefore strengthens the validity of this treatment strategy.

Benefits of Endovascular Treatment in Late Window for Acute Ischemic Stroke Selected without CT Perfusion: A Real-World Study

Objective

This study examined the functional outcomes and safety of endovascular treatment (EVT) in acute ischemic stroke (AIS) patients owing to large vessel occlusion of the anterior circulation, presented during a late-time window (6–24 hours after last seen well (LSW)) in a real-world practice.

Methods

This was a retrospective analysis from a bi-center prospective cohort. According to the stroke treatment, patients with continuous Alberta Stroke Plan Early Aspect score (ASPECTS) ≥6 on non-contrast CT (NCCT) and moderate to good collateral state on CT angiography (CTA) were divided into EVT group and standard medical treatment (SMT) group. The primary outcome was the rate of functional independence (90-day mRS ≤2). Safety outcomes were the occurrence of symptomatic intracranial hemorrhage (sICH) and the 90-day mortality.

Results

Among the 288 enrolled patients (53.5% male, median age 64 years), there were 167 patients in the EVT group and 121 in the SMT group. After multivariable adjustments for potential confounders, EVT was associated with functional independence (adjusted OR: 3.052; 95% confidence interval (CI): 1.553–5.997; p = 0.001). In the PSM cohort, 44.2% (42/95) of patients in the EVT group versus 18.9% (18/95) in the SMT group achieved functional independence (OR: 3.39, 95% CI: 1.763–6.517), and there was a significant difference favoring EVT over the SMT in the overall distribution of mRS (OR: 2.170, 95% CI: 1.302–3.618) at 90 days. The rate of sICH did not differ between the EVT and SMT groups (10.5% vs 8.4%, p = 0.804) nor did 90-day mortality (18.9% vs 22.1%, p = 0.719). No interaction was found in p-values with statistical significance in subgroup analysis.

Conclusion

This real-world experience suggests that EVT for late-presenting stroke patients, based on small core on NCCT and moderate to good collaterals on CTA, is associated with better outcomes than SMT alone, with no increase in sICH and 90-day mortality rates.

Acute stroke imaging selection for mechanical thrombectomy in the extended time window: is it time to go back to basics? A review of current evidence

Treatment with endovascular therapy in the extended time window for acute ischaemic stroke with large vessel occlusion involves stringent selection criteria based on the two landmark studies DAWN and DEFUSE3. Current protocols typically include the requirement of advanced perfusion imaging which may exclude a substantial proportion of patients from receiving a potentially effective therapy. Efforts to offer endovascular reperfusion therapies to all appropriate candidates may be facilitated by the use of simplified imaging selection paradigms with widely available basic imaging techniques, such as non-contrast CT and CT angiography. Currently available evidence from our literature review suggests that patients meeting simplified imaging selection criteria may benefit as much as those patients selected using advanced imaging techniques (CT perfusion or MRI) from endovascular therapy in the extended time window. A comprehensive understanding of the role of imaging in patient selection is critical to optimising access to endovascular therapy in the extended time window and improving outcomes in acute stroke. This article provides an overview on current developments and future directions in this emerging area.

Estimated number of eligible patients for mechanical thrombectomy based on NIHSS and population-based Brest stroke registry

BACKGROUND

Since 2015, mechanical thrombectomy (MT) is indicated as a treatment for patients with large vessel occlusion (LVO) at the acute phase of ischemic stroke. However, the number of stroke patients eligible for MT is poorly known.

OBJECTIVE

The objective of our study was to estimate the number of patients eligible for thrombectomy within the first 24hours of an ischemic stroke, based on the clinical National Institute of Health Stroke Scale (NIHSS).

METHOD

Our study concerned all ischemic strokes which occurred between January 2013 and December 2016 recorded in the population-based Brest Stroke Registry (BSR). Based on positive predictive value and negative predictive value from articles evaluating the performance of a defined NIHSS threshold to identify LVO, we first estimated the frequency of patients with LVO and then the frequency of patients eligible for MT depending on pre-stroke modified Rankin score (mRS). Our results were extrapolated to regions of metropolitan France. Two scenarios were considered: one called "stringent criteria" with mRS ≤1 and one called "real-life" criteria with mRS ≤2.

RESULT

We analyzed data from 2,025 ischemic strokes with symptom onset ≤24hours. No statistical difference between patient characteristics according to the time of hospital admission (≤6H vs. 6-24H) was observed. Based on NIHSS scores, between 23.90% and 44.20% of ischemic strokes admitted within the first six hours had LVO clinical characteristics. Among them, 14.53% to 26.87% met the ``stringent eligibility'' criteria for MT and 16.9 to 31.25% for ``real-life'' criteria. Eligible patients represented 6.32% to 11.70% of all ischemic strokes, irrespective of admission time. In France, 75 to 162 persons per million inhabitants per year were eligible for endovascular therapy, depending on including criteria. Based on activity levels recorded by the French Neuroradiology Society (SFNR) in 2018, the estimated needed increase in MT showed a heterogeneous pattern region-by-region, with the greatest need in Brittany, Pays de la Loire, and Corsica.

CONCLUSION

Based on NIHSS, our study provides coherent information concerning the estimated number of MT procedures to be performed in France: 4,877 to 10,494 ischemic strokes would be eligible each year in metropolitan France compared to the 6,596 thrombectomy procedures actually performed in 2018. Depending on the region, an estimated 10-20% to 90-100% increase in MT activity would be necessary to meet patient needs. These data suggest that there is still room for improvement in thrombectomy activity, particularly in certain regions of France, to allow equal access to MT to the entire French population.

Clinical protocol of the ischemic stroke patients treatment

Today in Ukraine there is no single standardized protocol for the treatment of patients in the acute period of ischemic stroke using modern methods of diagnosis and treatment, which include thrombolytic therapy and endovascular treatment. This protocol was created and implemented in Scientific-practical Center of endovascular neuroradiology, NAMS of Ukraine and is based on the latest recommendations of AHA/ASA and ESO, as well as registers of patients with ischemic stroke. The main purpose of this publication is the creation and implementation of «instructions» for the diagnosis and selection of objective tactics for treating patients in the acute period of ischemic stroke.

Global Epidemiology of Stroke and Access to Acute Ischemic Stroke Interventions

PURPOSE OF THE REVIEW

To provide an up-to-date review of the incidence of stroke and large vessel occlusion (LVO) around the globe, as well as the eligibility and access to IV thrombolysis (IVT) and mechanical thrombectomy (MT) worldwide.

RECENT FINDINGS

Randomized clinical trials have established MT with or without IVT as the usual care for patients with LVO stroke for up to 24 hours from symptom onset. Eligibility for IVT has extended beyond 4.5 hours based on permissible imaging criteria. With these advances in the last 5 years, there has been a notable increase in the population of patients eligible for acute stroke interventions. However, access to acute stroke care and utilization of MT or IVT is lagging in these patients.

SUMMARY

Stroke is the second leading cause of both disability and death worldwide, with the highest burden of the disease shared by low- and middle-income countries. In 2016, there were 13.7 million new incident strokes globally; ≈87% of these were ischemic strokes and by conservative estimation about 10%-20% of these account for LVO. Fewer than 5% of patients with acute ischemic stroke received IVT globally in the eligible therapeutic time window and fewer than 100,000 MTs were performed worldwide in 2016. This highlights the large gap among eligible patients and the low utilization rates of these advances across the globe. Multiple global initiatives are underway to investigate interventions to improve systems of care and bridge this gap.

Prognostic Scores for Large Vessel Occlusion Strokes

PURPOSE OF THE REVIEW

Endovascular thrombectomy (EVT) for large vessel occlusion strokes (LVOS) presents several treatment challenges. We provide a summary of existing tools for patient selection (pre-EVT tools) and for prognostication of long-term outcomes following reperfusion therapy (post-EVT tools).

RECENT FINDINGS

Recently published randomized trials demonstrated superiority of EVT over medical therapy alone for LVOS. Uniform patient selection paradigms based on demographic, clinical, and radiographic variables are not completely standardized, leading to variability in patient selection for EVT for LVOS. Post-EVT, an accurate assessment of long-term prognosis is critical in the decision-making process.

SUMMARY

Prognostic scores can serve as useful adjuncts to facilitate clinical decision-making during early management of patients with ischemic stroke, particularly those with LVOS. The acute management of LVOS comprises rapid clinical assessment, triage, and cerebrovascular imaging, followed by evaluation for candidacy for thrombolysis and EVT. Pre-EVT prognostic tools that accurately predict the likelihood of benefit from EVT may guide reliable, efficient, and cost-effective patient selection. Following EVT, severe stroke deficits and subacute poststroke complications that portend a poor prognosis may warrant invasive therapies. Clinical decisions regarding these treatment options involve careful discussions between providers and patient families, and are also based on prognosis provided by the treating clinician. Reliable post-EVT prognostic tools can facilitate this by providing accurate and objective prognostic information. Several prognostic tools have been developed and validated in the literature, some of which may be applicable in the pre-EVT and post-EVT settings, although clinical utility and application varies. Validation in contemporary datasets as well as implementation and impact studies are needed before these scales can be used to guide clinical decisions for individual patients.

Refined Ischemic Penumbra Imaging with Tissue pH and Diffusion Kurtosis Magnetic Resonance Imaging

Imaging has played a vital role in our mechanistic understanding of acute ischemia and the management of acute stroke patients. The most recent DAWN and DEFUSE-3 trials showed that endovascular therapy could be extended to a selected group of late-presenting stroke patients with the aid of imaging. Although perfusion and diffusion MRI have been commonly used in stroke imaging, the approximation of their mismatch as the penumbra is oversimplified, particularly in the era of endovascular therapy. Briefly, the hypoperfusion lesion includes the benign oligemia that does not proceed to infarction. Also, with prompt and effective reperfusion therapy, a portion of the diffusion lesion is potentially reversible. Therefore, advanced imaging that provides improved ischemic tissue characterization may enable new experimental stroke therapeutics and eventually further individualize stroke treatment upon translation to the clinical setting. Specifically, pH imaging captures tissue of altered metabolic state that demarcates the hypoperfused lesion into ischemic penumbra and benign oligemia, which remains promising to define the ischemic penumbra's outer boundary. On the other hand, diffusion kurtosis imaging (DKI) differentiates the most severely damaged and irreversibly injured diffusion lesion from the portion of diffusion lesion that is potentially reversible, refining the inner boundary of the penumbra. Altogether, the development of advanced imaging has the potential to not only transform the experimental stroke research but also aid clinical translation and patient management.

Non-contrast head CT alone for thrombectomy in acute ischemic stroke: analysis of the ANGEL-ACT registry

BACKGROUD

The goal of this study was to determine if the choice of imaging paradigm performed in the emergency department influences the procedural or clinical outcomes after mechanical thrombectomy (MT).

METHODS

This is a retrospective comparative outcome study which was conducted from the ANGEL-ACT registry. Comparisons were made between baseline characteristics and clinical outcomes of patients with acute ischemic stroke undergoing MT with non-contrast head computed tomography (NCHCT) alone versus patients undergoing NCHCT plus non-invasive vessel imaging (NVI) (including CT angiography (with or without CT perfusion) and magnetic resonance angiography). The primary outcome was the modified Rankin Scale (mRS) score at 90 days. Secondary outcomes included change in mRS score from baseline to 90 days, the proportions of mRS 0-1, 0-2, and 0-3, and dramatic clinical improvement at 24 hours. The safety outcomes were any intracranial hemorrhage (ICH), symptomatic ICH, and mortality within 90 days.

RESULTS

A total of 894 patients met the inclusion criteria; 476 (53%) underwent NCHCT alone and 418 (47%) underwent NCHCT + NVI. In the NCHCT alone group, the door-to-reperfusion time was shorter by 47 min compared with the NCHCT + NVI group (219 vs 266 min, P<0.001). Patients in the NCHCT alone group showed a smaller increase in baseline mRS score at 90 days (median 3 vs 2 points; P=0.004) after adjustment. There were no significant differences between groups in the remaining clinical outcomes.

CONCLUSIONS

In patients selected for MT using NCHCT alone versus NCHCT + NVI, there were improved procedural outcomes and smaller increases in baseline mRS scores at 90 days.

Late Thrombectomy in Clinical Practice : Retrospective Application of DAWN/DEFUSE3 Criteria within the German Stroke Registry

BACKGROUND AND PURPOSE

To provide real-world data on outcome and procedural factors of late thrombectomy patients.

METHODS

We retrospectively analyzed patients from the multicenter German Stroke Registry. The primary endpoint was clinical outcome on the modified Rankin scale (mRS) at 3 months. Trial-eligible patients and the subgroups were compared to the ineligible group. Secondary analyses included multivariate logistic regression to identify predictors of good outcome (mRS ≤ 2).

RESULTS

Of 1917 patients who underwent thrombectomy, 208 (11%) were treated within a time window ≥ 6-24 h and met the baseline trial criteria. Of these, 27 patients (13%) were eligible for DAWN and 39 (19%) for DEFUSE3 and 156 patients were not eligible for DAWN or DEFUSE3 (75%), mainly because there was no perfusion imaging (62%; n = 129). Good outcome was not significantly higher in trial-ineligible (27%) than in trial-eligible (20%) patients (p = 0.343). Patients with large trial-ineligible CT perfusion imaging (CTP) lesions had significantly more hemorrhagic complications (33%) as well as unfavorable outcomes.

CONCLUSION

In clinical practice, the high number of patients with a good clinical outcome after endovascular therapy ≥ 6-24 h as in DAWN/DEFUSE3 could not be achieved. Similar outcomes are seen in patients selected for EVT ≥ 6 h based on factors other than CTP. Patients triaged without CTP showed trends for shorter arrival to reperfusion times and higher rates of independence.

MRI software for diffusion-perfusion mismatch analysis may impact on patients' selection and clinical outcome

Objective

Impact of different MR perfusion software on selection and outcome of patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO) treated by endovascular thrombectomy (EVT) is unclear. We aimed at comparing two commercial MRI software, semi-automated with unadjusted (method A) and adjusted mask (method B), and fully automated (method C) in this setting.

Methods

MRI from 144 consecutive AIS patients with anterior circulation LVO was retrospectively analysed. All diffusion- and perfusion-weighted images (DWI-PWI) were post-processed with the three methods using standard thresholds. Concordance for core and hypoperfusion volumes was assessed with Lin’s test. Clinical outcome was compared between groups in patients who underwent successful EVT in the early and late time window.

Results

Mean core volume was higher and mean hypoperfusion volume was lower in method C than in methods A and B. In the early time window, methods A and B found fewer patients with a mismatch ratio ≤ 1.2 than method C (1/67 [1.5%] vs. 12/67 [17.9%], p = 0.0013). In the late time window, methods A and B found fewer patients with a mismatch ratio < 1.8 than method C (3/46 [6.5%] and 2/46 [4.3%] vs. 18/46 [39.1%], p ≤ 0.0002). More patients with functional independence at 3 months would not have been treated using method C versus methods A and B in the early (p = 0.0063) and late (p ≤ 0.011) time window.

Conclusions

MRI software for DWI-PWI analysis may influence patients’ selection before EVT and clinical outcome.

Key Points

• Method C detects fewer patients with favourable mismatch profile.

• Method C might underselect more patients with functional independence at 3 months.

• Software used before thrombectomy may influence patients’ outcome.

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.

[Border areas of thrombectomy]

Die mechanische Thrombektomie (MT) hat sich als Standardverfahren für die Behandlung akuter ischämischer Schlaganfälle aufgrund eines Verschlusses einer großen, proximalen Hirnarterie der vorderen Zirkulation etabliert. Dennoch sind nach aktuellen Guidelines noch große Patientenkollektive von dieser hocheffektiven Behandlungsmethode ausgeschlossen. Diese Arbeit gibt daher einen Überblick über mögliche Erweiterungen der Behandlungsindikationen für die MT, wie z. B. Patienten im erweiterten Zeitfenster, mit distalen Verschlüssen, mit großem Infarktkern oder auch für sehr alte (> 90 Jahre) und junge (0–17 Jahre) Patienten. Zusätzlich besprechen wir neue Entwicklungen in der interventionellen Behandlung von Schlaganfällen, wie z. B. neue Triage-Konzepte oder die Fragestellung, ob die zusätzliche intravenöse Thrombolyse bei MT-Patienten notwendig ist. Abschließend geben wir für die besprochenen Behandlungsindikationen unsere Einschätzungen basierend auf der aktuellen Literatur und unserer klinischen Erfahrung.

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.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Expanding indications for endovascular thrombectomy-how to leave no patient behind

Endovascular thrombectomy (EVT) has become standard of care for large vessel occlusion strokes but current guidelines exclude a large proportion of patients from this highly effective treatment. This review therefore focuses on expanding indications for EVT in several borderline indications such as patients in the extended time window, patients with extensive signs of infarction on admission imaging, elderly patients and patients with pre-existing deficits. It also discusses the current knowledge on intravenous thrombolysis as an adjunct to EVT and EVT as primary therapy for distal vessel occlusions, for tandem occlusions, for basilar artery occlusions and in pediatric patients. We provide clear recommendations based on current guidelines and further literature.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Endovascular stroke treatment after 6-24 hours only needs non-contrast CT

OBJECTIVES

Imaging selected patients with proximal anterior circulation stroke who demonstrate limited infarct may benefit from endovascular treatment beyond conventional time limits. Our aim was to evaluate the results of the EVT group series arriving between 6 and 24 hours from the onset of symptoms with (ASPECTS) ≥7 to our hospital (with 24/7 interventional neuroradiology) comparing them with those obtained in our prospectively registered series arriving between 0 and 6 hours.

MATERIALS AND METHODS

The inclusion criteria were ≥18 years, an interval between stroke and endovascular treatment of 6-24 hours, prestroke score mRS 0-2, no intracranial haemorrhage, (NIHSS) scale 8-22 and infarct evaluated by CT scan ≥7 in ASPECTS scale. Data, including patient demographics, neuroimaging findings, procedural details, recanalization rates and 90-day mRS, were collected.

RESULTS

Twelve of the 14 (85.71%) endovascular group patients who came to our centre between 6 and 24 hours had good outcomes at 90 days. To confirm our findings, we evaluated patients treated at our centre who met the selection criteria from January 2017 to September 2019. In this period, 382 patients with large vessel occlusion were treated endovascularly. 56 patients met all the criteria for inclusion and exclusion for our study. 31 of these 56 patients (56.36%) obtained a (mRS) scale ≤2 at three months. There was no significant difference (P = 0.063).

CONCLUSION

In circumstances of difficult access to MRI or CT perfusion, a computed tomography of ASPECTS ≥7 is sufficient to indicate endovascular treatment in a stroke of known onset between 6 and 24 hours.

Recanalization Therapy for Acute Ischemic Stroke with Large Vessel Occlusion: Where We Are and What Comes Next?

In the past 5 years, the success of multiple randomized controlled trials of recanalization therapy with endovascular thrombectomy has transformed the treatment of acute ischemic stroke with large vessel occlusion. The evidence from these trials has now established endovascular thrombectomy as standard of care. This review will discuss the chronological evolution of large vessel occlusion treatment from early medical therapy with tissue plasminogen activator to the latest mechanical thrombectomy. Additionally, it will highlight the potential areas in endovascular thrombectomy for acute ischemic stroke open to exploration and further progress in the next decade.

Acute ischemic stroke endovascular therapy

Endovascular therapy (EVT) has become the standard treatment for large-vessel occlusion (LVO) acute ischemic stroke (AIS). EVT is now indicated in patients up to 24h from their last known well, provided that the patient meets specific clinical and imaging criteria. Improvements in thrombectomy devices, techniques, and operator experience have allowed successful EVT of ICA terminus, M1-MCA occlusions as well as proximal M2-MCA, basilar artery occlusions, and revascularization of tandem lesions. Mechanical thrombectomy failures still occur due to several factors, however, highlighting the need for further device and technical improvements. An ongoing debate exists regarding the need for pre-EVT thrombolytic agents, thrombectomy techniques, distal occlusions, anesthesia methods, the role of advanced neuroimaging, the treatment of patients with larger infarct core, and those presenting with milder stroke symptoms. Many of these questions are the subject of current or upcoming clinical trials. This review aims to provide an outline and discussion about the established recommendations and emerging topics regarding EVT for LVO AIS.

Results of Mechanical Thrombectomy 6 Hours after Stroke Onset: Analysis of Multiple Stroke Centers in Fukushima Prefecture

Objective

The purpose of this study was to examine the efficacy and safety of mechanical thrombectomy in patients with acute occlusion of a large cerebral artery in the anterior circulation beyond 6 hours of the time last known to be well using the real-world clinical data collected from non-urban areas of Japan.

Methods

We analyzed a retrospective multicenter database collected at 10 thrombectomy capable primary stroke centers in Fukushima Prefecture. In all, 188 patients were presenting a large cerebral artery occlusion in the anterior circulation, that is, internal carotid and middle cerebral artery (M1 and M2 segment). In all, 158 patients received mechanical thrombectomy within 6 hours from symptom onset (early time window), and 30 patients exceeded 6 hours (late time window). We compared the patient background, outcomes, and safety variables between the two groups. The modified Rankin Scale (mRS) score of 0-2 at 90 days after treatment and the incidence of symptomatic intracranial hemorrhage were compared between groups to evaluate treatment efficacy and safety.

Results

There was no significant difference in the proportion of mRS score 0-2 at 90 days after treatment (51.3 vs. 46.7%: P = 0.644). However, symptomatic intracranial hemorrhage was more frequent in the late time window group (7.0 vs. 16.7%: P = 0.081). Symptomatic intracranial hemorrhage was a significant factor of a poor functional outcome in the late time window group (P = 0.022).

Conclusion

This study reflects the real-world results of mechanical thrombectomy in the non-urban areas of Japan. The treatment efficacy in the late time window patients was equivalent to that in the early time window patients. On the other hand, the incidence of symptomatic intracranial hemorrhage showed a trend to high in patients beyond 6 hours, which was a significant factor related to a poor functional outcome.

Imaging criteria across pivotal randomized controlled trials for late window thrombectomy patient selection

BACKGROUND

The DAWN and DEFUSE-3 trials showed the benefit of endovascular treatment (EVT) in acute ischemic stroke patients presenting beyond 6 hours from last known well (LKW) and selected by perfusion imaging criteria. The ESCAPE NA1-trial selected patients based on non-contrast CT (NCCT) Alberta Stroke Program Early CT Score (ASPECTS) and multiphase CT angiography (CTA) collateral status. This study compares baseline characteristics, workflow, and outcomes in the EVT arms of DAWN and DEFUSE-3 with late-window patients from the EVT-only arm of ESCAPE-NA1.

METHODS

Aggregate data on baseline characteristics, workflow, reperfusion quality, final infarct volume, and clinical outcomes (modified Rankin Score [mRS] at 90 days) in subjects enrolled in the DAWN and DEFUSE-3 EVT arms were compared with similar data from the ESCAPE-NA1 control arm (EVT-only arm) presenting beyond 6 hours from LKW using descriptive statistics.

RESULTS

Baseline characteristics among late-window patients in the ESCAPE NA1 trial were similar to those in the DAWN and DEFUSE-3 EVT arms. Median time from LKW-to-puncture in subjects enrolled in the ESCAPE NA1 trial was 9 hrs (IQR: 7.5-11 hours) when compared with DAWN (n=107; 12.8 hours, IQR: 10.6-16.7 hours) and DEFUSE-3 (n=92; 11.5 hours, IQR: 9.2-12.8 hours). Median post-treatment infarct-volume was largest in the ESCAPE NA1-patients (47 mL [IQR: 19-146] vs median 8 mL [IQR: 0-48] in the DAWN group and 35 mL [IQR: 18-82] in DEFUSE-3), while % mRS 0-2 at 90 days were similar across the three trials (ESCAPE NA1: 50/111 [45%], DAWN: 52/107 [49%], DEFUSE-3: 41/92 [45%]).

CONCLUSION

Patients enrolled beyond 6 hours from LKW in the ESCAPE-NA1 trial based on NCCT-ASPECTS and mCTA had similar clinical outcomes when compared with patients selected by perfusion imaging in the DAWN and DEFUSE-3 trials.

Pathway Design for Acute Stroke Care in the Era of Endovascular Thrombectomy: A Critical Overview of Optimization Efforts

The efficacy of intravenous thrombolysis and endovascular thrombectomy (EVT) for acute ischemic stroke is highly time dependent. Optimal organization of acute stroke care is therefore important to reduce treatment delays but has become more complex after the introduction of EVT as regular treatment for large vessel occlusions. There is no singular optimal organizational model that can be generalized to different geographic regions worldwide. Current dominant organizational models for EVT include the drip-and-ship- and mothership model. Guidelines recommend routing of suspected patients with stroke to the nearest intravenous thrombolysis capable facility; however, the choice of routing to a certain model should depend on regional stroke service organization and individual patient characteristics. In general, design approaches for organizing stroke care are required, in which 2 key strategies could be considered. The first entails the identification of interventions within existing organizational models for optimizing timely delivery of intravenous thrombolysis and/or EVT. This includes adaptive patient routing toward a comprehensive stroke center, which focuses particularly on prehospital triage tools; bringing intravenous thrombolysis or EVT to the location of the patient; and expediting services and processes along the stroke pathway. The second strategy is to develop analytical or simulation model-based approaches enabling the design and evaluation of organizational models before their implementation. Organizational models for acute stroke care need to take regional and patient characteristics into account and can most efficiently be assessed and optimized through the application of model-based approaches.

Performance of Automated Attenuation Measurements at Identifying Large Vessel Occlusion Stroke on CT Angiography

PURPOSE

Computed tomography angiography (CTA) is routinely used to detect large-vessel occlusion (LVO) in patients with suspected acute ischemic stroke; however, visual analysis is time consuming and prone to error. To evaluate solutions to support imaging triage, we tested performance of automated analysis of CTA source images (CTASI) at identifying patients with LVO.

METHODS

Stroke patients with LVO were selected from a prospectively acquired cohort. A control group was selected from consecutive patients with clinically suspected stroke without signs of ischemia on CT perfusion (CTP) or infarct on follow-up. Software-based automated segmentation and Hounsfield unit (HU) measurements were performed on CTASI for all regions of the Alberta Stroke Program Early CT score (ASPECTS). We derived different parameters from raw measurements and analyzed their performance to identify patients with LVO using receiver operating characteristic curve analysis.

RESULTS

The retrospective analysis included 145 patients, 79 patients with LVO stroke and 66 patients without stroke. The parameters hemispheric asymmetry ratio (AR), ratio between highest and lowest regional AR and M2-territory AR produced area under the curve (AUC) values from 0.95-0.97 (all p < 0.001) for detecting presence of LVO in the total population. Resulting sensitivity (sens)/specificity (spec) defined by the Youden index were 0.87/0.97-0.99. Maximum sens/spec defined by the specificity threshold ≥0.70 were 0.91-0.96/0.77-0.83. Performance in a small number of patients with isolated M2 occlusion was lower (AUC: 0.72-0.85).

CONCLUSION

Automated attenuation measurements on CTASI identify proximal LVO stroke patients with high sensitivity and specificity. This technique can aid in accurate and timely patient selection for thrombectomy, especially in primary stroke centers without CTP capacity.

May endovascular thrombectomy without CT perfusion improve clinical outcome?

BACKGROUND

DAWN and DEFUSE-3 trials demonstrated the benefit of endovascular thrombectomy in late-presenting acute ischemic strokes due to anterior circulation large vessel occlusion. The aim of our study is to evaluate results of endovascular thrombectomy in large intracranial vessel occlusion without perfusion CT patient selection.

METHODS

we reviewed our prospectively collected endovascular databases for patients with an acute stroke from March 2016 to October 2018, treated after 6 h from stroke onset, without perfusion CT selection. Baseline characteristics, procedural data, and outcomes were evaluated. A good outcome was defined as a 90-day modified Rankin Scale score of 0-2. The association between clinical and procedural parameters and functional outcome was assessed.

RESULTS

out of 212 patients 55 were treated after 6 h from stroke onset, 49 of which for an anterior circulation occlusion. 18/49 were functional independent at 90 days (mRS 0-2), Successful recanalization (mTICI 2b to 3) was achieved in 38/49 patients (77 %). Multivariate logistic regression indicated that a low baseline NIHSS was associated with favorable outcome (OR 0.66, 95 % CI 0.52-0.83, p-value 0.001).

CONCLUSIONS

in our retrospective analysis, baseline NIHSS is the only parameter that can predict good outcome (90-days mRS 0-2). We confirm data from recent papers assessing that perfusion CT can provide a better patients' selection compared to mCTA for large vessels occlusion treated beyond six hours from symptom onset.

Thrombectomy in DAWN- and DEFUSE-3-Ineligible Patients: A Subgroup Analysis From the BEST Prospective Cohort Study

BACKGROUND

Because of the overwhelming benefit of thrombectomy for highly selected trial patients with large vessel occlusion (LVO), some trial-ineligible patients are being treated in practice.

OBJECTIVE

To determine the safety and efficacy of thrombectomy in DAWN/DEFUSE-3-ineligible patients.

METHODS

Using a multicenter prospective observational study of consecutive patients with anterior circulation LVO who underwent late thrombectomy, we compared symptomatic intracerebral hemorrhage (sICH) and good outcome (90-d mRS 0-2) among DAWN/DEFUSE-3-ineligible patients to trial-eligible patients and to untreated DAWN/DEFUSE-3 controls.

RESULTS

Ninety-eight patients had perfusion imaging and underwent thrombectomy >6 h; 46 (47%) were trial ineligible (41% M2 occlusions, 39% mild deficits, 28% ASPECTS <6). In multivariable regression, the odds of a good outcome (aOR 0.76, 95% CI 0.49-1.19) and sICH (aOR 3.33, 95% CI 0.42-26.12) were not different among trial-ineligible vs eligible patients. Patients with mild deficits were more likely to achieve a good outcome (aOR 3.62, 95% CI 1.48-8.86) and less sICH (0% vs 10%, P = .16), whereas patients with ASPECTS <6 had poorer outcomes (aOR 0.14, 95% CI 0.05-0.44) and more sICH (aOR 24, 95% CI 5.7-103). Compared to untreated DAWN/DEFUSE-3 controls, trial-ineligible patients had more sICH (13%BEST vs 3%DAWN [P = .02] vs 4%DEFUSE [P = .05]), but were more likely to achieve a good outcome at 90 d (36%BEST vs 13%DAWN [P < .01] vs 17%DEFUSE [P = .01]).

CONCLUSION

Thrombectomy is used in practice for some patients ineligible for the DAWN/DEFUSE-3 trials with potentially favorable outcomes. Additional trials are needed to confirm the safety and efficacy of thrombectomy in broader populations, such as large core infarction and M2 occlusions.

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

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

Clinical considerations and assessment of risk factors when choosing endovascular thrombectomy for acute stroke

INTRODUCTION

The advent of endovascular thrombectomy (EVT) has been a game changer for the management of acute ischemic stroke due to large vessel occlusion. However, the selection of suitable candidates for EVT remains a significant challenge.

AREAS COVERED

This review focuses on the clinical, radiological, and procedural considerations for EVT in acute stroke that assist in optimal patient selection.

EXPERT OPINION

All patients presenting with significant clinical deficits with treatable occlusions, who have salvageable brain tissue at presentation might benefit from treatment up to twenty-four hours from symptom onset. Neuroimaging tools form the backbone for this decision making.

Time Intervals for Direct Versus Transfer Cases of Thrombectomy for Stroke in a Primarily Rural System of Care

BACKGROUND

Early treatment is the key to a successful recovery for ischemic stroke patients. From time of onset, a patient's chances of permanent disability only increase until they can receive reperfusion intervention.

OBJECTIVE

We sought to identify potential delays that occur during evaluation and treatment of patients in a rural regional health system.

METHODS

We conducted a single-center retrospective review of all patients that arrived at our comprehensive stroke center (CSC) between July 2011 and March 2017, and received thrombectomy, with or without prior treatment with intravenous recombinant tissue plasminogen activator.

RESULTS

One hundred and fifty-four patients met our criteria for inclusion. Patients were divided into 2 groups: Direct (patients brought to our CSC from scene) and Transfer (patients taken to an outside hospital then transferred to our CSC). The median time to CSC for Direct patients was 82 (range: 15-863) minutes after onset of symptoms, compared to 237 (range: 98-1215) minutes for the Transfer group. The median time for Transfer patients to reach an outside hospital was 74 (range: 5-840) minutes, with an additional average time of 90 minutes in the outside hospital prior to transferred to our CSC.

CONCLUSIONS

Based on our findings, patients brought directly to our CSC saved a significant amount of time, which may improve functional outcomes. Both groups (Direct and Transfer) spent a similar amount of time between last known normal and emergency medical services arrival, highlighting the need for increased awareness among the public to activate the stroke system of care.

Endovascular management of acute large vessel occlusion stroke in pregnancy is safe and feasible

INTRODUCTION

Stroke is a leading cause of adult death and disability. Although acute ischemic stroke (AIS) in pregnancy is rare, it has devastating consequences on the life of the mother and fetus. Pregnancy was an exclusion criterion in endovascular thrombectomy (EVT) trials and so there are no evidence-based treatment recommendations in this subgroup. The objective of this study was to evaluate the safety and feasibility of mechanical thrombectomy in large vessel occlusion (LVO) stroke in pregnancy.

METHODS

Patients with AIS due to LVO treated with EVT during pregnancy between 2000 and 2019 were identified at seven tertiary care centers. After IRB approval, retrospective analysis of prospectively maintained stroke/endovascular databases was performed.

RESULTS

A total of seven subjects were identified. The average age was 33.2 years (range 25-38 years) and the average initial National Institutes of Health Stroke Scale (NIHSS) score at presentation was 15 (range 9-28). Three patients received IV tissue plasminogen activator. Techniques of EVT included stent retriever thrombectomy, stent retriever-assisted continuous aspiration, direct contact aspiration, and multimodal techniques including a rescue balloon mounted coronary stent placement. While one patient was noted to have petechial hemorrhage, no individuals developed parenchymal hematoma. Mean discharge NIHSS score was 1.7 (range 0-5).

CONCLUSION

EVT is a safe and effective treatment for acute stroke secondary to LVO in this series of pregnant patients. While EVT for acute stroke is standard of care in select patient populations, our study suggests that treatment should be considered in the gravid population.

Comparison Between Perfusion- and Collateral-Based Triage for Endovascular Thrombectomy in a Late Time Window

Background and Purpose—

Perfusion-based triage has proven to be effective and safe for selecting patients who are likely to benefit from endovascular thrombectomy (EVT) in a late time window. We investigated collateral-based triage for EVT in patients presenting beyond 6 hours, in terms of interrater reliability and efficacy in predicting clinical outcome, in comparison to perfusion-based triage.

Methods—

One hundred and thirty-two patients who underwent both computed tomographic angiography and computed tomography perfusion for anterior circulation large artery occlusion 6 to 24 hours after last seen well were enrolled. Patients were classified into EVT-eligible and EVT-ineligible groups according to perfusion- and collateral-based triages. We evaluated the interrater reliability of collateral-based triage and differences in good outcome rates of patients who received EVT in the EVT-eligible groups based on perfusion- and collateral-based triages.

Results—

Both computed tomographic angiography and computed tomography perfusion were assessable in 93 patients. Seventy-six patients were eligible for EVT according to perfusion-based triage. Among them, EVT was performed in 58, of whom 32 (55.1%) had good outcome. Sixty-nine patients were eligible for EVT based on collateral-based triage. Among them, EVT was performed in 50 patients, of whom 31 (62.0%) had good outcome. Interrater reliability of collateral-based triage was good (generalized κ=0.73 [95% CI, 0.59–0.84]). Agreement on EVT eligibility between perfusion- and collateral-based triages was moderate (κ=0.41 [95% CI, 0.16–0.61]). There was no difference in good outcome rates of patients who underwent EVT in the EVT-eligible groups based on perfusion- and collateral-based triages (55.1% versus 62.0%; P =0.0675).

Conclusions—

Collateral-based triage showed good interrater reliability and comparable efficacy to that of perfusion-based triage in predicting clinical outcome after EVT in patients presenting beyond 6 hours. Collateral-based triage is a reliable approach for selecting patients for EVT in the extended therapeutic time window.

Eligibility for late endovascular treatment using DAWN, DEFUSE-3, and more liberal selection criteria in a stroke center

Background and purpose

The real-life application of DAWN and DEFUSE-3 trials has been poorly investigated. We aimed to identify the proportion of patients with acute ischemic stroke (AIS) eligible for late endovascular treatment (EVT) in our stroke center based on trial and more liberal selection criteria.

Methods

All consecutive patients in our stroke registry (2003–2017) admitted within 5–23 hours of last proof of good health were selected if they had complete clinical and radiological datasets. We calculated the proportion of patients eligible for late EVT according to trial (DAWN and/or DEFUSE-3) and more liberal clinical/imaging mismatch criteria (including lower admission National Institutes of Health Stroke Scale score and Alberta Stroke Program Early CT Score for core estimation).

Results

Of 1705 patients with AIS admitted to our comprehensive stroke center in the late time window, we identified 925 patients with complete clinical and radiological data. Among them, the proportions of late EVT eligibility were 2.5% (n=23) with DAWN, 5.1% (n=47) with DEFUSE-3, and 11.1% (n=103) with more liberal criteria. Considering late-arriving patients with large vessel occlusion (n=221), the percentages of eligible patients were 10.4%, 21.3%, and 46.6%, respectively. A favorable outcome was observed at comparable rates in treated patients selected by trial or liberal criteria (67% vs 58%, p=0.49).

Conclusions

In a long-term stroke registry, the proportion of late EVT eligibility varied greatly according to selection criteria and referral pattern. Among late-arriving patients referred to our comprehensive stroke center, we found 5.6% eligible according to trial (DAWN/DEFUSE-3) and 11.1% according to liberal criteria. These data indicate that late EVT could be offered to a larger population of patients if more liberal criteria are applied.

Mortality reduction after thrombectomy for acute intracranial large vessel occlusion: meta-analysis of randomized trials

Background

Thrombectomy for patients with emergent large vessel occlusion (ELVO) is currently recognized as the standard of care for appropriately selected patients. As proven in several randomized clinical trials and meta-analyses, treatment with thrombectomy lowers rates of poor functional outcomes after ELVO, compared with standard medical management. However, combined mortality rates of the most recent, high-quality clinical trials have not been collectively assessed.

Objective

The goal of this study was to assess the combined mortality rates of patients with ELVO following thrombectomy using data from the most recent, high-quality clinical trials.

Methods

Meta-analysis was performed in clinical trials comparing thrombectomy and medical management for patients with anterior circulation ELVO. Cumulative rates of mortality (mRS 6) as well as mortality or severe disability (mRS 5-6) were calculated.

Results

Ten clinical trials fit the inclusion criteria, including PISTE, REVASCAT, DAWN, THRACE, SWIFT PRIME, ESCAPE, DEFUSE 3, THERAPY, EXTEND-IA, and MR CLEAN, with 2233 patients assessed for mortality alone and 2229 for mortality or severe disability. There was a significantly reduced risk of death with thrombectomy compared with standard medical care (14.9% vs 18.3%, P=0.03; RR 0.81, 95% CI 0.67 to 0.98), as well as a reduced risk of mortality or severe disability (mRS 5–6) in ELVO patients treated with thrombectomy (21.1% vs 30.5%, P<0.0001; RR 0.69, 95% CI 0.60 to 0.80).

Conclusions

Overall, these results suggest a lower risk of death, as well as death or severe disability, in patients with ELVO treated with thrombectomy compared with medical management alone.