Brief History of Endovascular Acute Ischemic Stroke Treatment

Endovascular Treatment for Complex Vascular Pathologies in the Pediatric Population: Experience from a Center with Dual-Trained Neurosurgeons

OBJECTIVE

Endovascular treatment of complex vascular pathologies in the pediatric population is often performed by nonpediatric subspecialists with adaptation of equipment and techniques developed for adult patients. We aimed to report our center's experience with safety and outcomes of endovascular treatments for pediatric vascular pathologies.

METHODS

We performed a retrospective review of our endovascular database. All patients ≤18 years who underwent endovascular treatment between January 1, 2004 and December 1, 2022 were included.

RESULTS

During the study time frame, 118 cerebral angiograms were performed for interventional purposes in 55 patients. Of these patients, 8(14.5%) had intracranial aneurysms, 21(38.2%) had intracranial arteriovenous malformations, 6(10.9%) had tumors, 5(9.1%) had arterial occlusions (n = 3) or dissections (n = 2), 8(14.5%) had vein of Galen malformations, and 7(12.7%) had other cerebrovascular conditions. Of the total 118 procedures, access-site complications occurred in 2(1.7%), intraprocedural complications occurred in 3(2.5%), and transient neurological deficits were observed after 2(1.7%). Treatment-related mortality occurred in 1(1.8%) patient.

CONCLUSIONS

Neurointervention in pediatric patients was safe and effective in our experience.

Mechanical thrombectomy in medium vessel occlusions using the novel aspiration Q catheters: an international multicenter experience

BACKGROUND

Medium vessel occlusions (MeVOs) comprise a large proportion of all stroke events. We performed a multicenter study of MIVI Q catheters, a novel design that optimizes suction forces without an increase in lumen diameter, for the treatment of MeVOs, aiming to evaluate its efficacy and safety.

METHODS

Databases of two US and two UK centers were retrospectively reviewed for MeVO patients (M2-M3, anterior cerebral artery (ACA), or posterior cerebral artery (PCA)) treated with Q catheters. Outcomes were assessed as successful recanalization (modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2b), first pass effect (FPE), and modified FPE (mFPE) as single pass achieving mTICI ≥2c and mTICI≥2b, respectively, and 90 day modified Rankin Scale (mRS) score.

RESULTS

69 patients were included (median age 71 years, IQR 56-82.5; 52.2% men). Median National Institutes of Health Stroke Scale (NIHSS) score at admission was 14, and Alberta Stroke Program Early CT Score (ASPECTS) was 9. Primary (without large vessel occlusion (LVO)) and secondary (with LVO) MeVOs represented 47.8% and 52.2% of cases, respectively. Q catheters used were Q3 (47.8%), Q4 (33.3%), Q5 (10.1%), and Q6 (8.7%). mTICI≥2b was achieved in 92.8% of patients, with FPE in 47.8%, and mFPE in 68.1%. Two (2.9%) intraprocedural complications (symptomatic intracranial hemorrhage) occurred. 50% (27/54) achieved an mRS score of ≤2 at the 90 day follow-up. The median NIHSS at admission was significantly higher in secondary than in primary MeVOs (19.5 vs 12, P=0.009). The rate of mRS ≤2 at 90 days was significantly higher in primary than in secondary MeVOs (77.3% vs 31.3%, P=0.002).

CONCLUSIONS

Treatment of MeVO patients with Q catheters resulted in optimal angiographic and clinical outcomes. Although angiographic results were similar between primary and secondary MeVOs, the former had less severe presenting NIHSS and better outcomes at 90 days than the latter.

Hypothermia is Associated with Improved Neurological Outcomes After Mechanical Thrombectomy

BACKGROUND

Acute ischemic stroke (AIS) is the second leading cause of death globally. Mechanical thrombectomy (MT) has improved patient prognosis but expedient treatment is still necessary to minimize anoxic injury. Lower intraoperative body temperature decreases cerebral oxygen demand, but the role of hypothermia in treatment of AIS with MT is unclear.

METHODS

We retrospectively reviewed patients undergoing MT for AIS from 2014 to 2020 at our institution. Patient demographics, comorbidities, intraoperative parameters, and outcomes were collected. Maximum body temperature was extracted from minute-by-minute anesthesia readings, and patients with maximal temperature below 36°C were considered hypothermic. Risk factors were assessed by χ2 and multivariate ordinal regression.

RESULTS

Of 68 patients, 27 (40%) were hypothermic. There was no significant association of hypothermia with patient age, comorbidities, time since last known well, number of passes intraoperatively, favorable revascularization, tissue plasminogen activator use, and immediate postoperative complications. Hypothermic patients exhibited better neurologic outcome at 3-month follow-up (P = 0.02). On multivariate ordinal regression, lower maximum intraoperative body temperature was associated with improved 3-month outcomes (P < 0.001), when adjusting for other factors influencing neurological outcomes. Other significant protective factors included younger age (P = 0.03), better revascularization (P = 0.03), and conscious sedation (P = 0.02).

CONCLUSIONS

Lower intraoperative body temperature during MT was independently associated with improved neurological outcome in this single center retrospective series. These results may help guide clinicians in employing therapeutic hypothermia during MT to improve long-term neurologic outcomes from AIS, although larger studies are needed.

Endovascular Thrombectomy for the Treatment of Large Ischemic Stroke: A Systematic Review and Meta-Analysis of Randomized Control Trials

BACKGROUND AND OBJECTIVES

Endovascular thrombectomy has previously been reserved for patients with small to medium acute ischemic strokes. Three recent randomized control trials have demonstrated functional benefit and risk profiles for thrombectomy in large-volume ischemic strokes. The primary objective of the meta-analysis was to determine the combined benefit of endovascular thrombectomy in patients with large-volume ischemic strokes and to determine the risk of adverse events after treatment.

METHODS

We systematically searched Medical Literature Analysis and Retrieval System Online, Excerpta Medica Database, Scopus, the Cochrane Central Register, and Google Scholar for randomized trials published between January 1, 2010, and February 19, 2023. We included trials specifically comparing endovascular thrombectomy with medical therapy in adults with acute ischemic stroke with large-volume infarctions (defined by Alberta Stroke Program Early Computed Tomography Score 3-5 or a calculated infarct volume of >50 mL). Data were extracted based on prespecified variables on study methods and design, participant characteristics, analysis approach, and efficacy/safety outcomes. Results were combined using a restricted maximum-likelihood estimation random-effects model. Studies were assessed for potential bias and quality of evidence. The primary outcome was an overall ordinal shift across modified Rankin scale scores toward a better outcome at 90 days after either treatment arm.

RESULTS

Three thousand forty-four studies were screened, and 29 underwent full-text review. Three randomized trials (N = 1011) were included in the analysis. The pooled random-effects model for the primary outcome favored endovascular thrombectomy over medical management, with a generalized odds ratio of 1.55 (95% CI 1.25-1.91, I 2 = 42.84%). There was a trend toward increased risk of symptomatic intracranial hemorrhage in the thrombectomy group, with a relative risk of 1.85 (95% CI 0.94-3.63, I 2 = 0.00%).

CONCLUSION

In patients with large-volume ischemic strokes, endovascular thrombectomy has a clear functional benefit and does not confer increased risk of significant complications compared with medical management alone.

Differential thrombectomy utilization across hospital classifications in the United States

OBJECTIVES

To determine hospital-level factors associated with thrombectomy uptake.

MATERIALS AND METHODS

The Nationwide Emergency Department Sample was retrospectively queried to determine the total number of thrombectomies performed based on different hospital characteristics. Joint point analysis was used to determine which years were associated with significant increases in the number of high-volume thrombectomy centers (ostensibly defined as >50 thrombectomies/year), thrombectomy-capable centers (>15 thrombectomies/year), and total number of thrombectomies performed. Multivariable logistic regression was used to determine hospital factors associated with having an increased odds of performing thrombectomies, and of being classified as a high-volume thrombectomy or a thrombectomy-capable center.

RESULTS

Between 2007-2020 there was a stepwise increase in the number of thrombectomy-capable and high-volume thrombectomy centers in the United States. In 2020, there were a total of 15,705 thrombectomies performed, with 89 high-volume thrombectomy centers, and 359 thrombectomy-capable centers. The number of thrombectomy-capable centers significantly increased after 2011. After 2013 and 2016 there was a significant change in the growth rate of high-volume thrombectomy centers. There was also a significant increase in the total number of thrombectomies performed after 2016. Hospital characteristics that were associated with an increased likelihood of being classified as thrombectomy-capable or high-volume included trauma level 1 and 2 hospitals.

CONCLUSIONS

Between 2007 and 2020, there was a marked growth in thrombectomy utilization for acute ischemic stroke. This growth outpaced new diagnoses of ischemic stroke, and was driven largely by certain hospital types, with the greatest rises following seminal publications of positive randomized thrombectomy trials.

Rapid increasing burden of diabetes and cardiovascular disease caused by high body mass index in 1.25 million Chinese adults, 2005-2018

BACKGROUND

Temporal trends and geographical variations in disease burden for diabetes mellitus (DM) and cardiovascular disease (CVD) attributable to high body mass index (BMI) in China have not been fully elucidated.

METHODS

We estimated deaths and years of life lost (YLLs) for DM and CVD attributable to high BMI by age, sex, year, and region from 2005 to 2018 based on pooled data of 1.25 million adults.

FINDINGS

Approximately 497,430 (95% uncertainty interval [UI], 470,520-525,720) deaths for DM and CVD were attributable to high BMI in China in 2018, with 453,750 deaths from CVD and 43,700 deaths from DM. Between 2005 and 2018, there was a 17.35% increase in age-standardized mortality rate for DM and CVD attributable to high BMI. The high BMI-related DM and CVD YLL rates increased from 127.46 (95% UI 108.70-148.62) per 100,000 people aged 20-24 years to 5,735.54 (95% UI 4,844.16-6,713.53) per 100,000 people aged ≥80 years, respectively. The highest age-standardized mortality rate for high BMI-related DM and CVD in northeast, northwest, and circum-Bohai Sea regions of China.

CONCLUSION

The disease burden for DM and CVD attributable to high BMI increased substantially between 2005 and 2018. Urgent measures are required at both national and regional levels for resource mobilization to slow the growing burden.

FUNDING

The work was supported by the National Key Research and Development Program of China, China National Science & Technology Pillar Program, and National Health Commission of the People's Republic of China.

History of Neurointervention

In this review article, we aim to provide a summary of the discoveries and developments that were instrumental in the evolution of the Neurointerventional field. We begin with developments in the advent of Diagnostic Cerebral Angiography and progress to cerebral aneurysm treatment, embolization in AVMs and ischemic stroke treatment. In the process we discuss many persons who were key in the development and maturation of the field. A pivotal aspect to rapid growth in the field has been the multidisciplinary involvement of the different neuroscience specialties and therefore we close out our discussion with excitement about ongoing and future developments in the field with a focus on treatments in the non-cerebrovascular disease realm.

Immunocytoprotection after reperfusion with Kv1.3 inhibitors has an extended treatment window for ischemic stroke

Introduction: Mechanical thrombectomy has improved treatment options and outcomes for acute ischemic stroke with large artery occlusion. However, as the time window of endovascular thrombectomy is extended there is an increasing need to develop immunocytoprotective therapies that can reduce inflammation in the penumbra and prevent reperfusion injury. We previously demonstrated, that by reducing neuroinflammation, KV1.3 inhibitors can improve outcomes not only in young male rodents but also in female and aged animals. To further explore the therapeutic potential of KV1.3 inhibitors for stroke therapy, we here directly compared a peptidic and a small molecule KV1.3 blocker and asked whether KV1.3 inhibition would still be beneficial when started at 72 hours after reperfusion. Methods: Transient middle cerebral artery occlusion (tMCAO, 90-min) was induced in male Wistar rats and neurological deficit assessed daily. On day-8 infarction was determined by T2-weighted MRI and inflammatory marker expression in the brain by quantitative PCR. Potential interactions with tissue plasminogen activator (tPA) were evaluated in-vitro with a chromogenic assay. Results: In a direct comparison with administration started at 2 hours after reperfusion, the small molecule PAP-1 significantly improved outcomes on day-8, while the peptide ShK-223 failed to reduce infarction and neurological deficits despite reducing inflammatory marker expression. PAP-1 still provided benefits when started 72 hours after reperfusion. PAP-1 does not reduce the proteolytic activity of tPA. Discussion: Our studies suggest that KV1.3 inhibition for immunocytoprotection after ischemic stroke has a wide therapeutic window for salvaging the inflammatory penumbra and requires brain-penetrant small molecules.

Endovascular thrombectomy for the treatment of large ischemic stroke: a systematic review and meta-analysis of randomized control trials

Importance

Endovascular thrombectomy (ET) has previously been reserved for patients with small to medium acute ischemic strokes. Three recent randomized control trials (RCTs) have demonstrated functional benefit and risk profiles for ET in large volume ischemic strokes.

Objective

The primary objective of the meta-analysis was to determine the combined benefit of ET in adult patients with large volume acute ischemic strokes and to better determine the risk of adverse events following ET.

Data Sources

We systematically searched MEDLINE, EMBASE, SCOPUS, the Cochrane Central Register of Controlled, and Google Scholar for all RCTs published in English language between January 1, 2010, to February 19, 2023.

Study Selection

We included only RCTs specifically comparing ET to medical therapy in patients with acute ischemic stroke with large volume infarctions as defined by Alberta Stroke Program Early Computed Tomography Score (ASPECTS) 3-5 or calculated infarct volume of > 50-70mL. Two independent reviewers screened potential studies for full text review and metaanalysis inclusion with conflicts being resolved by consensus or third reviewer.

Data Extraction and Synthesis

Data was extracted based on pre-specified variables on study methods and design, participant characteristics, analysis approach, as well as efficacy and safety outcomes. Results were combined using a restricted maximum-likelihood estimation random-effects model. Studies were assessed for potential bias and quality of evidence.

Main Outcomes and Measures

The prespecified primary outcome was an overall ordinal shift across the range of modified Rankin scale scores toward a better outcome at 90 days following either ET or medical management for patients with large volume ischemic strokes.

Results

A total of 3044 studies were screened, and 29 underwent full text review. 3 RCTs (1011 patients) were included in the analysis. The pooled random effects model for the primary outcome of mRS improvement favored ET over medical management, generalized odds ratio 1.55 [95% CI 1.25 - 1.91, T ² = 0.01, I ² = 42.84%]. There was a trend toward increased risk of symptomatic ICH in the ET group, relative risk 1.85 [95% CI 0.94 - 3.63, T ² = 0.00, I ² = 0.00%].

Conclusions and Relevance

In patients with large volume ischemic strokes, ET has a clear functional benefit and does not confer increased risk of significant complications compared to medical management alone.

Head and neck angiography in the pediatric population: single-center experience with indications, safety, feasibility, and technical differences among infants, childhood, and adolescents

OBJECTIVE

Pediatric patients are candidates for head and neck endovascular procedures less frequently than adults. Data on utilization, feasibility, safety, and technical details of head and neck angiography in the pediatric population are scarce.

METHODS

The authors performed a retrospective review of their center's endovascular database to identify all patients ≤ 18 years of age who underwent diagnostic or interventional catheter-based angiography of the head and neck. Procedure-related variables for identified patients were compared across infancy (birth to 2 years), childhood (> 2-11 years), and adolescence (> 11-18 years).

RESULTS

One hundred twenty-one pediatric patients who underwent 274 angiogram procedures were included in this study. Of these angiograms, 197 were diagnostic and 118 were interventional (including 41 of the diagnostic angiogram procedures that were performed concurrently with the intervention). The most common indications for diagnostic angiograms were suspected vascular malformations in 52 cases (26.4%) and aneurysms in 23 (11.7%). The rate of positive findings on diagnostic angiograms ranged from 27.3% to 80% according to the indication. Access site-related complications were observed after 2 punctures (0.7%). Procedure-related complications occurred in 3 patients (1.1%). In adolescents, the rates of general anesthesia use and sheathless access were significantly lower (each p < 0.001), and the rates of radial artery access (p < 0.001); 5-French (5F) (p = 0.01), 6F (p < 0.001), and 8F (p = 0.03) access; and closure device usage (p < 0.001) were significantly higher. In infants, the rates of ultrasound guidance, 4F access, and failure of the primary puncture site were significantly higher (each p < 0.001).

CONCLUSIONS

Head and neck angiograms in the pediatric population were feasible and safe in the authors' overall experience. Technical differences were observed across the infant, childhood, and adolescent groups, but safe outcomes were similar throughout these age ranges.

The Mechanism Underlying the Regulation of Long Non-coding RNA MEG3 in Cerebral Ischemic Stroke

Cerebral ischemic stroke is one of the leading causes of morbidity and mortality worldwide, and rapidly increasing annually with no more effective therapeutic measures. Thus, the novel diagnostic and prognostic biomarkers are urgent to be identified for prevention and therapy of ischemic stroke. Recently, long noncoding RNAs (lncRNAs), a major family of noncoding RNAs with more than 200 nucleotides, have been considered as new targets for modulating pathological process of ischemic stroke. In this review, we summarized that the lncRNA-maternally expressed gene 3 (MEG3) played a critical role in promotion of neuronal cell death and inhibition of angiogenesis in response to hypoxia or ischemia condition, and further described the challenge of overcrossing blood-brain barrier (BBB) and determination of optimal carrier for delivering lncRNA' drugs into the specific brain regions. In brief, MEG3 will be a potential diagnostic biomarker and drug target in treatment and therapy of ischemic stroke in the future.

Endovascular Intervention in Acute Ischemic Stroke: History and Evolution

Stroke is a leading cause of serious long-term disability in the US. Endovascular therapy (EVT), in the form of mechanical thrombectomy, is now a standard of care for patients with acute ischemic stroke with a large vessel occlusion. This article reviews the evolution of EVT in the management of acute ischemic stroke and how it has led to the concept of tissue window over the widely publicized time window.

Transient Middle Cerebral Artery Occlusion with an Intraluminal Suture Enables Reproducible Induction of Ischemic Stroke in Mice

Ischemic stroke is a leading cause of mortality and chronic disability worldwide, underscoring the need for reliable and accurate animal models to study this disease's pathology, molecular mechanisms of injury, and treatment approaches. As most clinical strokes occur in regions supplied by the middle cerebral artery (MCA), several experimental models have been developed to simulate an MCA occlusion (MCAO), including transcranial MCAO, micro- or macro-sphere embolism, thromboembolisation, photothrombosis, Endothelin-1 injection, and - the most common method for ischemic stroke induction in murine models - intraluminal MCAO. In the intraluminal MCAO model, the external carotid artery (ECA) is permanently ligated, after which a partially-coated monofilament is inserted and advanced proximally to the common carotid artery (CCA) bifurcation, before being introduced into the internal carotid artery (ICA). The coated tip of the monofilament is then advanced to the origin of the MCA and secured for the duration of occlusion. With respect to other MCAO models, this model offers enhanced reproducibility regarding infarct volume and cognitive/functional deficits, and does not require a craniotomy. Here, we provide a detailed protocol for the surgical induction of unilateral transient ischemic stroke in mice, using the intraluminal MCAO model. Graphic abstract: Overview of the intraluminal monofilament method for transient middle cerebral artery occlusion (MCAO) in mouse.

Temporal trend and attributable risk factors of stroke burden in China, 1990–2019: an analysis for the Global Burden of Disease Study 2019

Background

Understanding the temporal trend of the disease burden of stroke and its attributable risk factors in China, especially at provincial levels, is important for effective prevention strategies and improvement. The aim of this analysis from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) is to investigate the disease burden of stroke and its risk factors at national and provincial levels in China from 1990 to 2019.

Methods

Following the methodology in the GBD 2019, the incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) of stroke cases in the Chinese population were estimated by sex, age, year, stroke subtypes (ischaemic stroke, intracerebral haemorrhage, and subarachnoid haemorrhage), and across 33 provincial administrative units in China from 1990 to 2019. Attributable mortality and DALYs of underlying risk factors were calculated by a comparative risk assessment.

Findings

In 2019, there were 3·94 million (95% uncertainty interval 3·43–4·58) new stroke cases in China. The incidence rate of stroke increased by 86·0% (73·2–99·0) from 1990, reaching 276·7 (241·3–322·0) per 100 000 population in 2019. The age-standardised incidence rate declined by 9·3% (3·3–15·5) from 1990 to 2019. Among 28·76 million (25·60–32·21) prevalent cases of stroke in 2019, 24·18 million (20·80–27·87) were ischaemic stroke, 4·36 million (3·69–5·05) were intracerebral haemorrhage, and 1·58 million (1·32–1·91) were subarachnoid haemorrhage. The prevalence rate increased by 106·0% (93·7–118·8) and age-standardised prevalence rate increased by 13·2% (7·7–19·1) from 1990 to 2019. In 2019, there were 2·19 million (1·89–2·51) deaths and 45·9 million (39·8–52·3) DALYs due to stroke. The mortality rate increased by 32·3% (8·6–59·0) from 1990 to 2019. Over the same period, the age-standardised mortality rate decreased by 39·8% (28·6–50·7) and the DALY rate decreased by 41·6% (30·7–50·9). High systolic blood pressure, ambient particulate matter pollution exposure, smoking, and diet high in sodium were four major risk factors for stroke burden in 2019. Moreover, we found marked differences of stroke burden and attributable risk factors across provinces in China from 1990 to 2019.

Interpretation

The disease burden of stroke is still severe in China, although the age-standardised incidence and mortality rates have decreased since 1990. The stroke burden in China might be reduced through blood pressure management, lifestyle interventions, and air pollution control. Moreover, because substantial heterogeneity of stroke burden existed in different provinces, improved health care is needed in provinces with heavy stroke burden.

Funding

National Key Research and Development Program of China and Taikang Yicai Public Health and Epidemic Control Fund.

Xenon Nanobubbles for the Image-Guided Preemptive Treatment of Acute Ischemic Stroke via Neuroprotection and Microcirculatory Restoration

Early lesion site diagnosis and neuroprotection are crucial to the theranostics of acute ischemic stroke. Xenon (Xe), as a nontoxic gaseous neuroprotectant, holds great promise for ischemic stroke therapy. In this study, Xe-encapsulated lipid nanobubbles (Xe-NBs) have been prepared for the real-time ultrasound image-guided preemptive treatment of the early stroke. The lipids are self-assembled at the interface of free Xe bubbles, and the mean diameter of Xe-NBs is 225 ± 11 nm with a Xe content of 73 ± 2 μL/mL. The in vitro results show that Xe-NBs can protect oxygen/glucose-deprived PC12 cells against apoptosis and oxidative stress. Based on the ischemic stroke mice model, the biodistribution, timely ultrasound imaging, and the therapeutic effects of Xe-NBs for stroke lesions were investigated in vivo. The accumulation of Xe-NBs to the ischemic lesion endows ultrasound contrast imaging with the lesion area. The cerebral blood flow measurement indicates that the administration of Xe-NBs can improve microcirculatory restoration, resulting in reduced acute microvascular injury in the lesion area. Furthermore, local delivery of therapeutic Xe can significantly reduce the volume of cerebral infarction and restore the neurological function with reduced neuron injury against apoptosis. Therefore, Xe-NBs provide a novel nanosystem for the safe and rapid theranostics of acute ischemic stroke, which is promising to translate into the clinical management of stroke.

Clot Composition Analysis as a Diagnostic Tool to Gain Insight into Ischemic Stroke Etiology: A Systematic Review

Mechanical thrombectomy renders the occluding clot available for analysis. Insights into thrombus composition could help establish the stroke cause. We aimed to investigate the value of clot composition analysis as a complementary diagnostic tool in determining the etiology of large vessel occlusion (LVO) ischemic strokes (International Prospective Register of Systematic Reviews [PROSPERO] registration # CRD42020199436). Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we ran searches on Medline (using the PubMed interface) and Web of Science for studies reporting analyses of thrombi retrieved from LVO stroke patients subjected to mechanical thrombectomy (January 1, 2006 to September 21, 2020). The PubMed search was updated weekly up to February 22, 2021. Reference lists of included studies and relevant reviews were hand-searched. From 1,714 identified studies, 134 eligible studies (97 cohort studies, 31 case reports, and six case series) were included in the qualitative synthesis. Physical, histopathological, biological, and microbiological analyses provided information about the gross appearance, mechanical properties, structure, and composition of the thrombi. There were non-unanimous associations of thrombus size, structure, and composition (mainly proportions of fibrin and blood formed elements) with the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiology and underlying pathologies, and similarities between cryptogenic thrombi and those of known TOAST etiology. Individual thrombus analysis contributed to the diagnosis, mainly in atypical cases. Although cohort studies report an abundance of quantitative rates of main thrombus components, a definite clot signature for accurate diagnosis of stroke etiology is still lacking. Nevertheless, the qualitative examination of the embolus remains an invaluable tool for diagnosing individual cases, particularly regarding atypical stroke causes.

Extended Middle Cerebral Artery Occlusion (MCAO) Model to Mirror Stroke Patients Undergoing Thrombectomy

Stroke remains a leading global cause of death and disability. In the last decade, the therapeutic window for mechanical thrombectomy has increased from a maximum of 6 to 24 h and beyond. While endovascular advancements have improved rates of recanalization, no post-stroke pharmacotherapeutics have been effective in enhancing neurorepair and recovery. New experimental models are needed to closer mimic the human patient. Our group has developed a model of transient 5-h occlusion in rats to mimic stroke patients undergoing thrombectomy. Our procedure was designed specifically in aged rats and was optimized based on sex in order to keep mortality and extent of injury consistent between aged male and female rats. This model uses a neurological assessment modeled after the NIH Stroke Scale. Finally, the potential for translation between our rat model of stroke and humans was assessed using comparative gene expression for key inflammatory genes. This model will be useful in the evaluation of therapeutic targets to develop adjuvant treatments for large vessel occlusion during the thrombectomy procedure.

Endovascular Thrombectomy after Large-Vessel Ischemic Stroke: Utilization, Outcomes, and Readmissions across the United States

Background Following publication of trials demonstrating the efficacy of thrombectomy, societal guidelines were revised in 2015 to recommend this procedure for large-vessel stroke. Purpose To evaluate real-world thrombectomy rates, adverse events, outcomes, and readmissions across the United States in the 2 years after large-scale adoption of thrombectomy for acute stroke. Materials and Methods In this retrospective study, the authors queried the National Inpatient Sample and Nationwide Readmissions Database for patients undergoing thrombectomy between 2016 and 2017. Thrombectomy rates were compared by using the χ² test. Adjusted risk ratios (aRRs) were obtained for factors affecting routine discharge, mortality, and readmission by using multivariable Poisson regression with clustering at the hospital level. Results There were 290 460 admissions (mean age, 70.5 years ± 14.2 [standard deviation]; 148 620 women) for internal carotid or middle cerebral artery stroke; 30 835 (10.6%) of these patients underwent thrombectomy. Thrombectomy rates were lower in patients aged 90 years or older (1815 of 24 090 patients, 7.5%), Black patients (4280 of 43 365 patients, 9.9%), patients with the lowest income (8520 of 85 905 patients, 9.9%), and those treated in West South Central division hospitals (2695 of 34 355 patients, 7.8%) (P < .001 for all). The inpatient mortality rate was 12.1% (3740 of 30 835 patients), and 19.1% of patients (5900 of 30 835) were discharged to home. In adjusted analyses, routine discharge was less likely in patients aged 90 years or older (aRR: 0.12; 95% CI: 0.09, 0.16; P < .001) and octogenarians (aRR: 0.37; 95% CI: 0.33, 0.41; P < .001). Patients aged 90 years or older (aRR: 1.78; 95% CI: 1.48, 2.14; P < .001), octogenarians (aRR: 1.76; 95% CI: 1.51, 2.06; P < .001), Asians and/or Pacific Islanders (aRR: 1.21; 95% CI: 1.06, 1.39; P = .005), and those treated in teaching (aRR: 1.20; 95% CI: 1.07, 1.34; P = .001) or West South Central division (aRR: 1.35; 95% CI: 1.14, 1.60; P < .001) hospitals had a higher risk of death. Following discharge, 18.9% of patients (3449 of 18 274) were readmitted within 90 days. Conclusion Rates and outcomes of thrombectomy are affected by demographic, socioeconomic, and hospital-related factors. Fewer than one-fifth of patients are discharged to home, nearly one-fifth are readmitted within 90 days, and mortality and outcomes may be less favorable than in published trials. © RSNA, 2021 Online supplemental material is available for this article.

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.

Biomechanics and hemodynamics of stent-retrievers

In 2015, multiple randomized clinical trials showed an unparalleled treatment benefit of stent-retriever thrombectomy as compared to standard medical therapy for the treatment of a large artery occlusion causing acute ischemic stroke. A short time later, the HERMES collaborators presented the patient-level pooled analysis of five randomized clinical trials, establishing class 1, level of evidence A for stent-retriever thrombectomy, in combination with intravenous thrombolysis when indicated to treat ischemic stroke. In the years following, evidence continues to mount for expanded use of this therapy for a broader category of patients. The enabling technology that changed the tide to support endovascular treatment of acute ischemic stroke is the stent-retriever. This review summarizes the history of intra-arterial treatment of stroke, introduces the biomechanics of embolus extraction with stent-retrievers, describes technical aspects of the intervention, provides a description of hemodynamic implications of stent-retriever embolectomy, and proposes future directions for a more comprehensive, multi-modal endovascular approach for the treatment of acute ischemic stroke.

Blood Pressure Management Following Large Vessel Occlusion Strokes: A Narrative Review

Stroke is one of the leading causes of morbidity and mortality worldwide. Intravenous tissue plasminogen activator and mechanical thrombectomy comprise the two major treatments for acute ischemic stroke. Tissue plasminogen activator has been used for more than two decades and guidelines for hemodynamic management following tissue plasminogen activator administration are well established. However, mechanical thrombectomy is a relatively newer therapy and there is a paucity of evidence regarding hemodynamic management following large vessel occlusion strokes. The important tenets guiding the pathophysiology of large vessel occlusion strokes include understanding of cerebral autoregulation, collateral circulation, and blood pressure variability. In this narrative review, we discuss the current American Heart Association-American Stroke Association guidelines for the early management of acute ischemic stroke during different phases of the illness, encountered at different sections of a hospital including the emergency room, the neuro-interventional suite, and the intensive care unit. There is emerging evidence with regard to post-recanalization blood pressure management following large vessel occlusion strokes. Future research directions will include rea-ltime blood pressure variability assessments, identifying the extent of impaired autoregulation, and providing guidelines related to range and personalized blood pressure trajectories for patients following large vessel occlusion strokes.

Hyperbaric oxygen therapy in acute stroke: is it time for Justitia to open her eyes?

Hypoxia is a critical component of neuronal death in patients with stroke. Therefore increasing oxygenation of brain tissue seems to be a logical therapy against cerebral ischemia. Oxygen therapy exists in two modalities: normobaric hyperoxia therapy and hyperbaric oxygen therapy (HBO). HBO is a therapeutic procedure in which pure (100%) oxygen is administered at greater than atmospheric pressure in HBO therapy chambers. In this review article, we aimed to summarize the current knowledge regarding the therapeutic use of HBO in acute stroke patients. Literature review and electronic search were performed using PubMed, Medscape, and UpToDate with the keywords stroke, acute stroke, hyperbaric oxygen therapy, and hyperoxia. According to the reviewed literature, the use of HBO as routine stroke therapy cannot be justified in acute stage of stroke. More randomized, controlled studies are needed regarding safety and especially effectives of HBO in stroke patients. Also, standardized definitionof HBO should be proposed and used in all future studies.

Smart diagnostic nano-agents for cerebral ischemia

A summary of the latest developments on imaging techniques and smart nano-diagnostics used for ischemic stroke.

Role of Balloon Guide Catheter in Modern Endovascular Thrombectomy

Proximal flow control achieved with a balloon guide catheter (BGC) during endovascular treatment of acute ischemic stroke is reviewed in this article. In clinical practice, BGCs offer a multi-faceted approach for clot retrieval by creating proximal flow arrest, reducing embolic burden, and shortening procedure time. Evaluation of frontline thrombectomy procedures with BGCs revealed advantages of combined use over the conventional guide catheter (CGC), notably in the significant reduction of distal emboli to both the affected and previously unaffected territories. Recently, new measures of early and complete reperfusion at first thrombectomy pass have been identified as independent predictors of improved outcomes, which were consistently demonstrated with use of BGC as a safe and effective option to minimize number of passes during intervention. Prior randomized controlled trials reported the positive correlation between BGC-treated patients and a lower risk of mortality as well as shortened procedure time. While BGC use is more common in stent retriever-mediated mechanical thrombectomy, preliminary data has shown the potential benefit of device application during contact aspiration thrombectomy to achieve successful recanalization. However, the question of which major endovascular strategy reigns superior as a frontline remains to be answered. Along with clinical case assessments, BGC performance during in-vitro simulation was analyzed to further understand mechanisms for optimization of thrombectomy technique.

Global, regional, and national burden of stroke, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND

Stroke is a leading cause of mortality and disability worldwide and the economic costs of treatment and post-stroke care are substantial. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic, comparable method of quantifying health loss by disease, age, sex, year, and location to provide information to health systems and policy makers on more than 300 causes of disease and injury, including stroke. The results presented here are the estimates of burden due to overall stroke and ischaemic and haemorrhagic stroke from GBD 2016.

METHODS

We report estimates and corresponding uncertainty intervals (UIs), from 1990 to 2016, for incidence, prevalence, deaths, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs). DALYs were generated by summing YLLs and YLDs. Cause-specific mortality was estimated using an ensemble modelling process with vital registration and verbal autopsy data as inputs. Non-fatal estimates were generated using Bayesian meta-regression incorporating data from registries, scientific literature, administrative records, and surveys. The Socio-demographic Index (SDI), a summary indicator generated using educational attainment, lagged distributed income, and total fertility rate, was used to group countries into quintiles.

FINDINGS

In 2016, there were 5·5 million (95% UI 5·3 to 5·7) deaths and 116·4 million (111·4 to 121·4) DALYs due to stroke. The global age-standardised mortality rate decreased by 36·2% (-39·3 to -33·6) from 1990 to 2016, with decreases in all SDI quintiles. Over the same period, the global age-standardised DALY rate declined by 34·2% (-37·2 to -31·5), also with decreases in all SDI quintiles. There were 13·7 million (12·7 to 14·7) new stroke cases in 2016. Global age-standardised incidence declined by 8·1% (-10·7 to -5·5) from 1990 to 2016 and decreased in all SDI quintiles except the middle SDI group. There were 80·1 million (74·1 to 86·3) prevalent cases of stroke globally in 2016; 41·1 million (38·0 to 44·3) in women and 39·0 million (36·1 to 42·1) in men.

INTERPRETATION

Although age-standardised mortality rates have decreased sharply from 1990 to 2016, the decrease in age-standardised incidence has been less steep, indicating that the burden of stroke is likely to remain high. Planned updates to future GBD iterations include generating separate estimates for subarachnoid haemorrhage and intracerebral haemorrhage, generating estimates of transient ischaemic attack, and including atrial fibrillation as a risk factor.

FUNDING

Bill & Melinda Gates Foundation.

Endovascular Stroke Therapy

Ischemic stroke is a leading cause of death and disability throughout the world and is both preventable and treatable. This review focuses on the treatment of the most severe form of ischemic stroke, namely large-vessel ischemic stroke, using endovascular techniques. Such therapies were proven effective in 2015. These therapies are among the most beneficial surgical therapies ever subjected to randomized clinical trials. Recent research has explored treating patients up to 24 h following the onset of stroke using advanced imaging techniques to select patients with brain tissue still at risk. These new findings suggest there exists a tissue clock rather than a time clock when selecting patients for therapy. Stroke systems throughout the world are now embracing endovascular stroke therapy. Improving regional stroke systems of care and expanding eligibility for patients are a major focus of current research.

Treatment for ischemic stroke: From thrombolysis to thrombectomy and remaining challenges

Stroke is a leading cause of death and long-term disabilities. Despite decades of extensive efforts in search of brain injury mechanisms and therapeutic interventions, pharmacological treatment is limited to the use of thrombolytic agent tissue plasminogen activator, which has limited therapeutic time window and potential side effect of intracranial hemorrhage. Over the past few years, endovascular thrombectomy with stent-retriever devices combined with advanced imaging modalities has transformed the standard of stroke care, offering an opportunity to improve the outcome in selected patients as late as 24 h after the onset of stroke. This mini-review summarizes the advancement in the treatment of ischemic stroke, from thrombolysis to thrombectomy and remaining challenges in the field.

Intravenous thrombolysis for acute ischemic stroke: a bridge between two centuries

INTRODUCTION

Intravenous tissue-plasminogen activator (tPA) remains the only approved systemic reperfusion therapy suitable for most patients presenting timely with acute ischemic stroke. Accumulating real-word experience for over 20 years regarding tPA safety and effectiveness led to re-appraisal of original contraindications for intravenous thrombolysis (IVT). Areas covered: This narrative review focuses on fast yet appropriate selection of patients for safe administration of tPA per recently expanded indications. Novel strategies for rapid patient assessment will be discussed. The potential for mobile stroke units (MSU) that shorten onset-to-needle time and increase tPA treatment rates is addressed. The use of IVT in the era of non-vitamin K antagonist oral anticoagulants (NOACs) is highlighted. The continuing role of IVT in large vessel occlusion (LVO) patients eligible for mechanical thrombectomy (MT) is discussed with regards to 'drip and ship' vs. 'mothership' treatment paradigms. Promising studies of penumbral imaging to extend IVT beyond the 4.5-hour window and in wake-up strokes are summarized. Expert commentary: This review provides an update on the role of IVT in specific conditions originally considered tPA contraindications. Novel practice challenges including NOAC's, MSU proliferation and bridging therapy (IVT&MT) for LVO patients, and the potential extension of IVT time-window using penumbral imaging are emerging as safe and potentially effective IVT applications.

Recent Trends in Clot Retrieval Devices: A Review

Stroke is the second leading cause of death worldwide and in Europe. Even with gold standard medical management of acute ischemic stroke, which is intravenous (IV) thrombolysis by administration of recombinant tissue plasminogen activator (rt-PA), the mortality rate remains the same. Intra-arterial (IA) thrombolysis therapy also did not achieve significant results and was not approved by the US Food and Drug Administration (FDA) because of limited sample size. This encouraged scientists and engineers to develop endovascular clot retrieval devices for the mechanical recanalization of the occluded arteries in stroke patients. Although the initial designs of clot retrieval devices failed, efforts to improve these devices continue. Recently clot retrieval devices were approved by the FDA as first-line treatment along with IV rt-PA. This article gives an in-depth review of different clot retrieval devices which includes MERCI (the first), the Penumbra Aspiration System, EmboTrap^®II, stent retrievers, and the way forward with the new FDA clearance of the devices as first-line treatment for acute ischemic stroke along with IV rt-PA. The review also includes a comparison of clot retrieval devices to gold standard treatment.

Would a Large tPA Trial for Those 4.5 to 6.0 Hours from Stroke Onset Be Good Value for Information?

OBJECTIVES

To quantify the potential value of new research in patients treated with thrombolytic treatment (tissue-type plasminogen activator [tPA]) in the 4.5- to 6.0-hour time window after stroke onset and to determine the optimal size of a future trial using value of information analysis.

METHODS

Expected value of partial perfect and sample information (EVPPI and EVSI) analyses were conducted using a probabilistic Markov model. Data for modified Rankin Scale (mRS) distributions in patients 4.5 to 6.0 hours since stroke onset for tPA (n = 576) and placebo (n = 543) were obtained from pooled randomized controlled trials. EVSI was quantified with net monetary benefit (assuming willingness to pay for health as $100,000/QALY). We calculated discounted population-level EVSI by multiplying per-person EVSI by the annual number of eligible patients with stroke in the United States and assuming a 10-year time frame of treatment use. Study costs were based on administrative costs and the costs of tPA.

RESULTS

The base-case lifetime cost-effectiveness analysis showed that tPA was dominated by placebo in this patient group. EVPPI for mRS distributions was $1003 per person. On the basis of EVSI, the optimal sample size of a new trial collecting data on tPA efficacy in these patients would be 5600 across study arms with expected population-level societal returns (EVSI minus study costs) of $68.7 million.

CONCLUSIONS

Expanding research attention to the 4.5- to 6.0-hour time window for tPA treatment of patients with acute ischemic stroke is justified because the expected returns are substantial. Even a relatively large trial in which more information on treatment efficacy on the basis of mRS scores is collected would represent good value for information.