Safety and efficacy of mechanical embolectomy in acute ischemic stroke: results of the MERCI trial

The safety and efficacy of NeVa mechanical thrombectomy device in acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Recent favorable cohort studies on endovascular therapy for ischemic stroke have predominantly utilized NeVa thrombectomy (NeVaTM) stent retrievers. We carried out a systematic review and meta-analysis to investigate the efficacy and safety of this second-generation stent retriever in acute ischemic stroke patients.

METHOD

We conducted the study according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The electronic databases of PubMed, Embase, and Scopus were searched until 26 November 2023 and was updated on August 1, 2024.

RESULTS

This meta-analysis systematically investigated 11 studies with a total of 805 patients suffering from ischemic stroke. The mean age of participants across the studies ranged from 65 to 77 years with a male preponderance of 50.16 %. While ten studies reported on the etiology of strokes, some studies reported the risk factors such as hypertension, dyslipidemia, diabetes, history of coronary artery disease, and previous stroke. The results of our study indicate that the all-hemorrhagic complications rate was 0.32 (95 %CI: 0.18-0.45), while the complete arterial recanalization rate was 0.76 [95 %CI: 0.49-1.04]. The overall recanalization rate was found to be 0.97 [95 %CI: 0.94-1.00]. Moreover, the postoperative hemorrhage rate was 0.28 [95 %CI: 0.14-0.41], while the repeated re-thrombosis rate was 0.01 [95 %CI: -0.01-0.03]. Lastly, the vasospasm rate was calculated to be 0.09 [95 %CI: -0.03-0.21].

CONCLUSION

NeVa™ is a safe option capable of achieving a high rate of recanalization and functional independence.

ABBREVIATIONS

PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PROSPERO, International Prospective Register of Systematic Reviews; NeVa™, NeVa Thrombectomy; ICH, Intracranial Hemorrhage; mTICI, modified Thrombolysis in Cerebral Infarction; mRS, modified Rankin Scale; ACA, Anterior Cerebral Artery; MCA, Middle Cerebral Artery; PCA, Posterior Cerebral Artery; ICA, Internal Carotid Artery; NIHSS, National Institutes of Health Stroke Scale.

Multicenter clinical trial evaluating the safety and efficacy of mechanical thrombectomy using the Versi Retriever

BACKGROUND

This study aimed to elucidate the safety and efficacy of mechanical thrombectomy using the Versi Retriever in patients with acute ischemic stroke (AIS).

METHODS

This was a prospective, multicenter, single-arm study conducted at 10 institutes in Japan from December 2018 to March 2021 on mechanical thrombectomy using the Versi Retriever in patients with AIS. The primary efficacy outcome was the modified Rankin scale (mRS) 0-2 at 90 days after the procedure. The primary safety outcome was mortality within 90 days after the procedure.

RESULTS

Fifty-eight patients with a mean age of 72.7 years were enrolled in the study. The primary efficacy outcome of mRS 0-2 at 90 days was 62.0% (95% CI 47.2-75.3%) in patients within 8 hours of stroke onset. The rate of immediate reperfusion of Thrombolysis in Cerebral Infarction (TICI) grade 2b-3 using the Versi Retriever in three passes was 78.0% (64.0-88.5%). The rate of final reperfusion of TICI 2b-3 was 100% (92.9-100%). The primary safety outcome of mortality within 90 days was 8.0% (2.2-19.2%) in patients within 8 hours of AIS onset. The incidence of intracranial hemorrhage within 24 hours was 12.0% (4.5-24.3%) for symptomatic cases and 32.0% (19.5-46.7%) for asymptomatic cases.

CONCLUSION

The Versi Retriever proved to be a safe and effective option for mechanical thrombectomy in patients with AIS.

Endovascular management of acute stroke

Stroke related to large vessel occlusion is a leading cause of disability and death worldwide. Advances in endovascular therapy to reopen occluded arteries have been shown to reduce patient disability and mortality. Expanded indications to treat patients with large vessel occlusion in the late window (>6 h from symptom onset), with basilar artery occlusion, and with large ischaemic core at presentation have enabled treatment of more patients with simplified imaging methods. Ongoing knowledge gaps include an understanding of which patients with large ischaemic infarct are more likely to benefit from endovascular therapy, the role of endovascular therapy in patients who present with low National Institutes of Health Stroke Scale scores or medium or distal vessel occlusion, and optimal management of patients with underlying intracranial atherosclerotic disease. As reperfusion can now be facilitated by intravenous thrombolysis, mechanical thrombectomy, or both, the development of cytoprotective or adjunctive drugs to slow infarct growth, enhance reperfusion, or decrease haemorrhagic risk has gained renewed interest with the hope to improve patient outcomes.

Fabrication of Shape Memory Polymer Endovascular Thrombectomy Device for Treating Ischemic Stroke

Stroke is the second result for death and ischemic stroke constitutes most of all stroke cases. Ischemic stroke takes place when blood clot or embolus blocks cerebral vessel and interrupts blood flow, which often leads to brain damage, permanent disability, or death. There is a 4.5-h (golden hour) treatment window to restore blood flow prior to permanent neurological impairment results. Current stroke treatments consist mechanical system or thrombolytic drug therapy to disrupt or dissolve thrombus. Promising method for stroke treatment is mechanical retrieving of thrombi employing device deployed endovascularly. Advent of smart materials has led to research fabrication of several minimally invasive endovascular devices that take advantage of new materials capabilities. One of these capabilities is shape memory, is capability of material to store temporary form, then activate to primary shape as subjected to stimuli. Shape memory polymers (SMPs) are employed as good materials for thrombectomy device fabrication. Therefore, current review presents thrombectomy device development and fabrication with SMPs. Design, performance, limitations, and in vitro or in vivo clinical results of SMP-based thrombectomy devices are identified. Review also sheds light on SMP's future outlook and recommendations for thrombectomy device application, opening a new era for advanced materials in materials science.

The cerebroprotection and prospects of FNDC5/irisin in stroke

Stroke, the leading cause of disability and cognitive impairment, is also the second leading cause of death worldwide. The drugs with multi-targeted brain cytoprotective effects are increasingly being advocated for the treatment of stroke. Irisin, a newly discovered myokine produced by cleavage of fibronectin type III domain 5, has been shown to regulate glucose metabolism, mitochondrial energy, and fat browning. A large amount of evidence indicated that irisin could exert anti-inflammatory, anti-apoptotic, and antioxidant properties in a variety of diseases such as myocardial infarction, inflammatory bowel disease, lung injury, and kidney or liver disease. Studies have found that irisin is widely distributed in multiple brain regions and also plays an important regulatory role in the central nervous system. The most common cause of a stroke is a sudden blockage of an artery (ischemic stroke), and in some circumstances, a blood vessel rupture can also result in a stroke (hemorrhagic stroke). After a stroke, complicated pathophysiological processes lead to serious brain injury and neurological dysfunction. According to recent investigations, irisin may protect elements of the neurovascular unit by acting on multiple pathological processes in stroke. This review aims to outline the currently recognized effects of irisin on stroke and propose possible directions for future research.

Effect of early vs. delayed extubation on functional outcome among patients with acute ischemic stroke treated with endovascular thrombectomy under general anesthesia: the prospective, randomized controlled EDESTROKE trial study protocol

BACKGROUND

Recent meta-analyses and randomized studies have shown that among patients with acute ischemic stroke undergoing endovascular thrombectomy, general anesthesia with mechanical ventilation is associated with better functional status compared to local anesthesia and sedation, and they recommend its use. But once the procedure is completed, when is the optimal moment for extubation? Currently, there are no guidelines recommending the optimal moment for extubation. Prolonged mechanical ventilation time could potentially be linked to increased complications such as pneumonia or disturbances in cerebral blood flow due to the vasodilatation produced by most anesthetic drugs. However, premature extubation in a patient who has suffered a stroke could led to complications such as agitation, disorientation, abolished reflexes, sudden fluctuations in blood pressure, alterations in cerebral blood flow, respiratory distress, bronchial aspiration, and the need for reintubation. We therefore designed a randomized study hypothesizing that early compared with delayed extubation is associated with a better functional outcome 3 months after endovascular thrombectomy treatment under general anesthesia for acute ischemic stroke.

METHODS

This investigator-initiated, single-center, prospective, parallel, evaluated blinded, superiority, randomized controlled trial will include 178 patients with a proximal occlusion of the anterior circulation treated with successful endovascular thrombectomy (TICI 2b-3) under general anesthesia. Patients will be randomly allocated to receive early (< 6 h) or delayed (6-12 h) extubation after the procedure. The primary outcome measure is functional independence (mRS of 0-2) at 90 days, measured with the modified Rankin Score (mRS), ranging from 0 (no symptoms) to 6 (death).

DISCUSSION

This will be the first trial to compare the effect of mechanical ventilation duration (early vs delayed extubation) after satisfactory endovascular thrombectomy for acute ischemic stroke under general anesthesia.

TRIAL REGISTRATION

The study protocol was approved April 11, 2023, by the by the Santiago-Lugo Research Ethics Committee (CEI-SL), number 2023/127, and was registered into the clinicaltrials.gov clinical trials registry with No. NCT05847309. Informed consent is required. Participant recruitment begins on April 18, 2023. The results will be submitted for publication in a peer-reviewed journal and presented at one or more scientific conferences.

Incidence and clinical outcomes of perforations during mechanical thrombectomy for medium vessel occlusion in acute ischemic stroke: A retrospective, multicenter, and multinational study

BACKGROUND

Mechanical thrombectomy (MT) has revolutionized the treatment of acute ischemic stroke (AIS) due to large vessel occlusion (LVO), but its efficacy and safety in medium vessel occlusion (MeVO) remain less explored. This multicenter, retrospective study aims to investigate the incidence and clinical outcomes of vessel perforations (confirmed by extravasation during an angiographic series) during MT for AIS caused by MeVO.

METHODS

Data were collected from 37 academic centers across North America, Asia, and Europe between September 2017 and July 2021. A total of 1373 AIS patients with MeVO underwent MT. Baseline characteristics, procedural details, and clinical outcomes were analyzed.

RESULTS

The incidence of vessel perforation was 4.8% (66/1373). Notably, our analysis indicates variations in perforation rates across different arterial segments: 8.9% in M3 segments, 4.3% in M2 segments, and 8.3% in A2 segments (p = 0.612). Patients with perforation had significantly worse outcomes, with lower rates of favorable angiographic outcomes (TICI 2c-3: 23% vs 58.9%, p < 0.001; TICI 2b-3: 56.5% vs 88.3%, p < 0.001). Functional outcomes were also worse in the perforation group (mRS 0-1 at 3 months: 22.7% vs 36.6%, p = 0.031; mRS 0-2 at 3 months: 28.8% vs 53.9%, p < 0.001). Mortality was higher in the perforation group (30.3% vs 16.8%, p = 0.008).

CONCLUSION

This study reveals that while the occurrence of vessel perforation in MT for AIS due to MeVO is relatively rare, it is associated with poor functional outcomes and higher mortality. The findings highlight the need for increased caution and specialized training in performing MT for MeVO. Further prospective research is required for risk mitigation strategies.

Neuroprotective effects of anti-TRAIL-ICG nanoagent and its multimodal imaging evaluation in cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury (CIRI) is a major challenge to neuronal survival in acute ischemic stroke (AIS). However, effective neuroprotective agents remain to be developed for the treatment of CIRI. In this work, we have developed an Anti-TRAIL protein-modified and indocyanine green (ICG)-responsive nanoagent (Anti-TRAIL-ICG) to target ischemic areas and then reduce CIRI and rescue the ischemic penumbra. In vitro and in vivo experiments have demonstrated that the carrier-free nanoagent can enhance drug transport across the blood-brain barrier (BBB) in stroke mice, exhibiting high targeting ability and good biocompatibility. Anti-TRAIL-ICG nanoagent played a better neuroprotective role by reducing apoptosis and ferroptosis, and significantly improved ischemia-reperfusion injury. Moreover, the multimodal imaging platform enables the dynamic in vivo examination of multiple morphofunctional information, so that the dynamic molecular events of nanoagent can be detected continuously and in real time for early treatment in transient middle cerebral artery occlusion (tMCAO) models. Furthermore, it has been found that Anti-TRAIL-ICG has great potential in the functional reconstruction of neurovascular networks through optical coherence tomography angiography (OCTA). Taken together, our work effectively alleviates CIRI after stoke by blocking multiple cell death pathways, which offers an innovative strategy for harnessing the apoptosis and ferroptosis against CIRI.

Introducing the Futile Recanalization Prediction Score (FRPS): A Novel Approach to Predict and Mitigate Ineffective Recanalization after Endovascular Treatment of Acute Ischemic Stroke

Objective: This study aims to develop and validate the Futile Recanalization Prediction Score (FRPS), a novel tool designed to predict the severity risk of FR and aid in pre- and post-EVT risk assessments. Methods: The FRPS was developed using a rigorous process involving the selection of predictor variables based on clinical relevance and potential impact. Initial equations were derived from previous meta-analyses and refined using various statistical techniques. We employed machine learning algorithms, specifically random forest regression, to capture nonlinear relationships and enhance model performance. Cross-validation with five folds was used to assess generalizability and model fit. Results: The final FRPS model included variables such as age, sex, atrial fibrillation (AF), hypertension (HTN), diabetes mellitus (DM), hyperlipidemia, cognitive impairment, pre-stroke modified Rankin Scale (mRS), systolic blood pressure (SBP), onset-to-puncture time, sICH, and NIHSS score. The random forest model achieved a mean R-squared value of approximately 0.992. Severity ranges for FRPS scores were defined as mild (FRPS < 66), moderate (FRPS 66-80), and severe (FRPS > 80). Conclusions: The FRPS provides valuable insights for treatment planning and patient management by predicting the severity risk of FR. This tool may improve the identification of candidates most likely to benefit from EVT and enhance prognostic accuracy post-EVT. Further clinical validation in diverse settings is warranted to assess its effectiveness and reliability.

Matched-pair analysis of patients with ischemic stroke undergoing thrombectomy using next-generation balloon guide catheters

BACKGROUND

Balloon guide catheters (BGCs) have not been widely adopted, possibly due to the incompatibility of past-generation BGCs with large-bore intermediate catheters. The next-generation BGC is compatible with large-bore catheters. We compared outcomes of thrombectomy cases using BGCs versus conventional guide catheters.

METHODS

We conducted a retrospective study of 110 thrombectomy cases using BGCs (n=55) and non-BGCs (n=55). Sixty consecutive thrombectomy cases in whom the BOBBY BGC was used at a single institution between February 2021 and March 2022 were identified. Of these, 55 BGC cases were 1:1 matched with non-BGC cases by proceduralists, age, gender, stent retriever + aspiration device versus aspiration-only, and site of occlusion. First-pass effect was defined as Thrombolysis In Cerebral Infarction 2b or higher with a single pass.

RESULTS

The BGC and non-BGC cohorts had similar mean age (67.2 vs 68.9 years), gender distribution (43.6% vs 47.3% women), median initial National Institutes of Health Stroke Scale score (14 vs 15), and median pretreatment ischemic core volumes (12 mL vs 11.5 mL). BGC and non-BGC cases had similar rates of single pass (60.0% vs 54.6%), first-pass effect (58.2% vs 49.1%), and complications (1.8% vs 9.1%). In aspiration-only cases, the BGC cohort had a significantly higher rate of first-pass effect (100% vs 50.0%, p=0.01). BGC was associated with a higher likelihood of achieving a modified Rankin Scale score of 2 at discharge (OR 7.76, p=0.02). No additional procedural time was required for BGC cases (46.7 vs 48.2 min).

CONCLUSION

BGCs may be safely adopted with comparable procedural efficacy, benefits to aspiration-only techniques, and earlier functional improvement compared with conventional guide catheters.

Real-World Impact of Modern Reperfusion Therapy for Acute Ischemic Stroke : A Nationwide Population-Based Data Study in Korea

OBJECTIVE

The treatment paradigm for acute ischemic stroke has undergone several major changes in the past decade, contributing to improved patient prognosis in clinical practice. However, the extent to which these changes have affected patient prognosis in the real-world is yet to be clarified. This study aimed to evaluate the real-world impact of modern reperfusion therapy for acute ischemic stroke using data from the National Health Insurance Service in Korea.

METHODS

This study included patients aged 18-80 years who were admitted via the emergency room with an I63 code between 2011 and 2020. The rates of intravenous thrombolysis use and endovascular treatment according to the year of admission were investigated. Furthermore, the rates of decompressive craniectomy and 3-month mortality were also analyzed. The 10-year observational period was divided into three periods based on the 2015 guideline change as follows : prior, 2011-2014; transitional, 2015-2016; and modern, 2017-2020.

RESULTS

A total of 307117 patients (mean age, 65.7±10.9 years) were included, and most patients were male (59.7%). The rate of endovascular treatment gradually increased during the study period from 0.71% in the prior period to 1.32% in the transitional period and finally to 1.85% in the modern period. Meanwhile, the 3-month mortality rate gradually decreased from 4.78% in the prior period to 4.03% in the transitional period and to 3.71% in the modern period.

CONCLUSION

In Korea, the mortality rate decreased as the rate of modern reperfusion therapy increased in patients with acute ischemic stroke. Overall, technical and scientific advances in reperfusion therapy have improved the outcome of patients with acute ischemic stroke in Korea.

Clinical Grading Scales and Neuroprognostication in Acute Brain Injury

Prediction of neurological clinical outcome after acute brain injury is critical because it helps guide discussions with patients and families and informs treatment plans and allocation of resources. Numerous clinical grading scales have been published that aim to support prognostication after acute brain injury. However, the development and validation of clinical scales lack a standardized approach. This in turn makes it difficult for clinicians to rely on prognostic grading scales and to integrate them into clinical practice. In this review, we discuss quality measures of score development and validation and summarize available scales to prognosticate outcomes after acute brain injury. These include scales developed for patients with coma, cardiac arrest, ischemic stroke, nontraumatic intracerebral hemorrhage, subarachnoid hemorrhage, and traumatic brain injury; for each scale, we discuss available validation studies.

Mechanical Thrombectomy with Intravenous Thrombolysis versus Thrombolysis Alone for the Treatment of Stroke: A Systematic Review of Economic Evaluations

Mechanical thrombectomy has revolutionized the management of stroke by improving the recanalization rates and reducing deleterious consequences. It is now the standard of care despite the high financial cost. A considerable number of studies have evaluated its cost effectiveness. Therefore, this study aimed to identify economic evaluations of mechanical thrombectomy with thrombolysis compared with thrombolysis alone to provide an update of existing evidence, focusing on the period after proof of effectiveness of mechanical thrombectomy. Twenty-one studies were included in the review: 18 were model-based economic evaluations to simulate long-term outcomes and costs, and 19 were conducted in high-income countries. Incremental cost-effectiveness ratios ranged from -$5,670 to $74,216 per quality-adjusted life year. Mechanical thrombectomy is cost-effective in high-income countries and in the populations selected for clinical trials. However, most of the studies used the same data. There is a lack of real-world and long-term data to analyze the cost effectiveness of mechanical thrombectomy in treating the global burden of stroke.

Endovascular Treatment plus Medical Treatment versus Medical Treatment Alone in Ischemic Stroke: A Systematic Review and Meta-Analysis

INTRODUCTION

This study was conducted to assess the hypothesis that endovascular treatment in addition to medical treatment improve stroke mortality and post-stroke disability.

METHODS

In this systematic review and meta-analysis, the studies were included if they were randomized controlled trials in design and compared between endovascular treatment and medical therapy versus medical therapy alone in stroke management.

RESULTS

The search yielded 22 articles that included 5,049 patients. The analysis showed significant association between the intervention and reduction in disability measured by Modified Rankin Scale (mRS) (mRS = 0-2) (odds ratio [OR] = 1.61; 95% confidence intervals [95% CI]: 1.27-2.06) and National Institute of Health Stroke Scale (NIHSS) (NIHSS = 0-15) (OR = 2.13; 95% CI: 1.04-4.34). Also, we found a significant difference in disability scores between the intervention and the medical therapy group (mRS weighted mean difference [WMD] = -0.59; 95% CI: -1.15 to -0.02, NIHSS WMD = -4.52; 95% CI: -6.32 to -2.72). Additionally, there was significant reduction in mortality in the intervention group (OR = 0.79; 95% CI: 0.68-0.92). There was no significant difference in the rate of any serious adverse effects between the two study groups except for asymptomatic intracerebral hemorrhage.

CONCLUSION

Our study provides strong evidence stemmed from randomized clinical trials that endovascular treatment combined with medical therapy is superior to medical therapy alone in the management of stroke.

Milestones in the history of neurocritical care

Over the last century, significant milestones have been achieved in managing critical illness and diagnosing and treating neurological diseases. Building upon these milestones, the field of neurocritical care emerged in the 1980 and 1990 s at the convergence of critical care medicine and acute neurological treatment. This comprehensive review presents a historical account of key developments in neurocritical care in both the United States and Europe, with a special emphasis on German contributions. The scope of the review encompasses: the foundations of neurocritical care, including post-operative units in the 1920s and 30s, respiratory support during the poliomyelitis epidemics in the 40 and 50 s, cardiac and hemodynamic care in the 60 and 70 s, and stroke units in the 80 and 90 s; key innovations including cerebral angiography, computed tomography, and intracranial pressure and multi-modal monitoring; and advances in stroke, traumatic brain injury, cardiac arrest, neuromuscular disorders, meningitis and encephalitis. These advances have revolutionized the management of neurological emergencies, emphasizing interdisciplinary teamwork, evidence-based protocols, and personalized approaches to care.

A review of mechanical thrombectomy techniques for acute ischemic stroke

Mechanical thrombectomy is established as standard of care in the management of acute ischemic stroke due to large vessel occlusion and evidence-based guidelines for mechanical thrombectomy have been defined. As research continues to further expand the eligibility criteria for thrombectomy and the number of thrombectomy procedures increase worldwide, there is also growing focus on innovation of thrombectomy devices, procedural techniques, and related outcomes. Thrombectomy primarily involves use of stent retrievers and distal aspiration techniques, but variations and different combinations of techniques have been reported. As this is a rapidly evolving area in stroke management, there is debate as to which, if any, of these techniques leads to improved clinical outcomes over another and there is a lack of data comparing them. In this review, currently published and distinct techniques of mechanical thrombectomy are described methodically along with illustrations to aid in understanding the subtle differences between the techniques. The perceived benefits of each variation are discussed.

Advances in Acute Ischemic Stroke Treatment: Current Status and Future Directions

The management of acute ischemic stroke has undergone a paradigm shift in the past decade. This has been spearheaded by the emergence of endovascular thrombectomy, along with advances in medical therapy, imaging, and other facets of stroke care. Herein, we present an updated review of the various stroke trials that have impacted and continue to transform stroke management. It is critical for the radiologist to stay abreast of the ongoing developments to provide meaningful input and remain a useful part of the stroke team.

Understanding ASPECTS of stroke: Inter-rater reliability between emergency medicine physician and radiologist in a rural setup

PURPOSE

The purpose is to determine the inter-rater reliability in grading ASPECTS score, between emergency medicine physician at first contact and radiologist among patients with acute ischemic stroke.

MATERIALS AND METHODS

We conducted a prospective analysis of 765 acute ischemic stroke cases referred to the Department of Radiodiagnosis in a rural-based hospital in South India, during January 2017 to October 2021. Non-contrast computed tomography (NCCT) scans of the brain were performed using GE Bright Speed Elite 128 Slice CT Scanner. ASPECTS score was calculated separately by an emergency medicine physician and radiologist. Inter-rater reliability for total and dichotomized ASPECTS (≥6 and <6) scores were assessed using statistical analysis (ICC and Cohen ĸ coefficients) on SPSS software (v17.0).

RESULTS

Inter-rater agreement for total and dichotomized ASPECTS was substantial (ICC 0.79 and Cohen ĸ 0.68) between the emergency physician and the radiologist. Mean difference in ASPECTS between the two readers was only 0.15 with standard deviation of 1.58. No proportionality bias was detected. The Bland-Altman plot was constructed to demonstrate the distribution of ASPECTS differences between the two readers.

CONCLUSION

Substantial inter-rater agreement was noted in grading ASPECTS between emergency medicine physician at first contact and radiologist, thereby confirming its robustness even in a rural setting.

The many roles of urgent catheter interventions: from myocardial infarction to acute stroke and pulmonary embolism

INTRODUCTION

Cardiovascular diseases (CVDs) are the leading cause of cardiovascular mortality and a major contributor to disability worldwide. The prevalence of CVDs is continuously increasing, and from 1990 to 2019, it has doubled. Global cardiovascular mortality has increased from 12.1 million in 1990 to 18.6 million cases in 2019. The development of therapeutic options for these diseases is at the forefront of interest concerning the extensive socio-economic consequences. Modern endovascular transcatheter therapeutic options contribute to the reduction of cardiovascular morbidity and mortality.

AREAS COVERED

The article concentrates on the triad of the most common causes of acute cardiovascular mortality and morbidity - myocardial infarction, ischemic stroke, and pulmonary embolism. Current evidence-based indications, specific interventional techniques, and remaining unsolved issues are reviewed and compared. A personal perspective on the possible implications for the future is provided.

EXPERT OPINION

Primary angioplasty for ST-segment elevation myocardial infarction is a well-established therapeutic option with proven mortality benefits. We suppose that catheter-based interventions for acute stroke will spread quickly from centers of excellence to routine clinical practice. We believe that ongoing research will provide a basis for the expansion of interventional treatment of pulmonary embolism soon.

Tumor Necrosis Factor (TNF)-α-Stimulated Gene 6 (TSG-6): A Promising Immunomodulatory Target in Acute Neurodegenerative Diseases

Tumor necrosis factor (TNF)-α-stimulated gene 6 (TSG-6), the first soluble chemokine-binding protein to be identified in mammals, inhibits chemotaxis and transendothelial migration of neutrophils and attenuates the inflammatory response of dendritic cells, macrophages, monocytes, and T cells. This immunoregulatory protein is a pivotal mediator of the therapeutic efficacy of mesenchymal stem/stromal cells (MSC) in diverse pathological conditions, including neuroinflammation. However, TSG-6 is also constitutively expressed in some tissues, such as the brain and spinal cord, and is generally upregulated in response to inflammation in monocytes/macrophages, dendritic cells, astrocytes, vascular smooth muscle cells and fibroblasts. Due to its ability to modulate sterile inflammation, TSG-6 exerts protective effects in diverse degenerative and inflammatory diseases, including brain disorders. Emerging evidence provides insights into the potential use of TSG-6 as a peripheral diagnostic and/or prognostic biomarker, especially in the context of ischemic stroke, whereby the pathobiological relevance of this protein has also been demonstrated in patients. Thus, in this review, we will discuss the most recent data on the involvement of TSG-6 in neurodegenerative diseases, particularly focusing on relevant anti-inflammatory and immunomodulatory functions. Furthermore, we will examine evidence suggesting novel therapeutic opportunities that can be afforded by modulating TSG-6-related pathways in neuropathological contexts and, most notably, in stroke.

Impact of Decompressive Craniectomy on Hemorrhagic Transformation in Malignant Ischemic Stroke in Mice

BACKGROUND

Endovascular thrombectomy has changed the management of ischemic stroke. The reperfusion can however lead to a hemorrhagic transformation (HT). Decompressive craniectomy (DC) is a surgical procedure used for malignant ischemic stroke. However, its efficacy was demonstrated before the era of endovascular thrombectomy trials. Here, we hypothesized that DC for ischemic stroke after thrombectomy could lead to a higher risk of HT. We thus evaluated this hypothesis in a mouse model of stroke induced by occlusion of the middle cerebral artery (MCAO) with or without mechanical reperfusion.

METHODS

Ninety mice subjected to MCAO were divided into 6 groups: permanent MCAO with or without DC; MCAO followed by a mechanical reperfusion with or without DC and MCAO with a mechanical reperfusion followed by r-tPA (recombinant tissue-type plasminogen activator)-induced reperfusion with or without DC. Mice were evaluated by magnetic resonance imaging 24 hours after the MCAO to assess ischemic lesion volumes, and the rate, type, and volume of HTs.

RESULTS

The ischemic volume was higher in the 2 groups without reperfusion than in the 4 groups with reperfusion independently of r-tPA treatment and DC. The distribution of HT types was different between the 6 groups. The HT volumes and HT scores was smaller in the 2 groups without reperfusion and in the reperfusion group without r-tPA and without DC. In mice having reperfusion, the mean HT score was higher in mice who had DC without r-tPA (HT score 5; P=0.048) or with r-tPA (HT score 8; P=0.02), than in mice without DC (HT score 1).

CONCLUSIONS

DC for a malignant stroke, after reperfusion, corresponding to an endovascular thrombectomy failure, increases the risk of severe hemorrhagic transformations in a model of ischemic stroke in mice. This result support the need of clinical studies to evaluate the added value of DC at the era of endovascular thrombectomy.

Upper-Limb Motor Intervention Elements That Drive Improvement in Biomarkers and Clinical Measures Post-Stroke: A Systematic Review in a Systems Paradigm

Objective

To use a systems paradigm to examine upper limb (UL) motor intervention elements driving biomarker and clinical measure improvement after stroke.

Methods

Databases were searched up to March 2022. Eligibility screening was completed by 2 authors. Studies using biomarkers and clinical measures pre- and post-upper limb intervention were included. Studies of adjunct interventions (eg, brain stimulation) were excluded. Cochrane Risk-of-Bias tools and Template for Intervention Description and Replication were used to rate studies. Studies were synthesized using a systems paradigm: intervention outcome was considered an emergent property of the systemic interactions of 4 intervention elements (demographics, type, quality, and dose) characterized by individual dimensions.

Results

Sixty-four studies (n = 1814 participants) containing 106 intervention groups (66 experimental; 40 control) were included. Combined biomarker and clinical outcomes defined 3 scenarios: restitution, mixed, and unchanged. The restitution scenario included more moderate-to-severely impaired participants in earlier recovery phases (<6 months). Interventions with graded difficulty were more frequently used in the restitution scenario compared with the unchanged scenario. No difference in quality or amount of therapy was identified when examining scenarios that demonstrated restitution compared to those that did not (mixed and unchanged).

Conclusions

A systems paradigm may be one of many approaches to understand UL motor restitution. This review found no single element consistently delivered improvements in biomarkers and clinical measures in the examined intervention groups. Complex patterns formed by multiple interacting intervention elements were observed in participants with and without restitution.

De novo headache in ischemic stroke patients treated with thrombectomy: a prospective study

Background and aim

Headache attributed to intracranial endovascular procedures is described in the ICHD-3. Our aim was to study the frequency and characteristics of headache specifically related to thrombectomy in patients with ischemic stroke.

Methods

Prospective evaluation of clinical features of headache after thrombectomy using an ad hoc questionnaire.

Results

One hundred seventeen patients were included (52.1% females). Most had an anterior circulation artery occlusion (91.5%). 93 (79.5%) received general anaesthesia. 111 (94.9%) required stent retriever, 21 (24.4%) angioplasty and 19 (16.2%) aspiration thrombectomy. 31 (26.5%; 95% CI 18.8–35.5%) had headache related to thrombectomy, and it was associated with a history of primary headache (p = 0.004). No differences about sex, initial NIHSS score, or the type or complexity of the procedure were observed. Headache was usually moderate and oppressive, ipsilateral to the artery occlusion and usually lasted less than 48 hours.

Conclusions

Almost one-third of patients with ischemic stroke who undergo endovascular thrombectomy experience headache in the first 24 hours, occurring more frequently in patients who had a previous history of headaches regardless of the procedure complexity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01455-3.

- About one third of the patients who undergo a thrombectomy for acute stroke experience headache directly related to the procedure.

- Having a previous history of primary headache is associated with the presence of headache after thrombectomy.

- Headache related to thrombectomy usually coincides with the distribution of the affected artery, although it is bilateral in 45% of the cases, mostly oppressive, of an average duration between 1 and 2 days and of a moderate intensity.

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

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

Practicalities of Impracticability: An Interim Review of Randomized Controlled Trials

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

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

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

Stentrievers : An engineering review

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

Oxidative Stress in Ischemia/Reperfusion Injuries following Acute Ischemic Stroke

Recanalization therapy is increasingly used in the treatment of acute ischemic stroke. However, in about one third of these patients, recanalization is followed by ischemia/reperfusion injuries, and clinically to worsening of the neurological status. Much research has focused on unraveling the involved mechanisms in order to prevent or efficiently treat these injuries. What we know so far is that oxidative stress and mitochondrial dysfunction are significantly involved in the pathogenesis of ischemia/reperfusion injury. However, despite promising results obtained in experimental research, clinical studies trying to interfere with the oxidative pathways have mostly failed. The current article discusses the main mechanisms leading to ischemia/reperfusion injuries, such as mitochondrial dysfunction, excitotoxicity, and oxidative stress, and reviews the clinical trials with antioxidant molecules highlighting recent developments and future strategies.

CT-based radiomics for differentiating intracranial contrast extravasation from intraparenchymal haemorrhage after mechanical thrombectomy

OBJECTIVE

To develop a nonenhanced CT-based radiomic signature for the differentiation of iodinated contrast extravasation from intraparenchymal haemorrhage (IPH) following mechanical thrombectomy.

METHODS

Patients diagnosed with acute ischaemic stroke who underwent mechanical thrombectomy in 4 institutions from December 2017 to June 2020 were included in this retrospective study. The study population was divided into a training cohort and a validation cohort. The nonenhanced CT images taken after mechanical thrombectomy were used to extract radiomic features. The maximum relevance minimum redundancy (mRMR) algorithm was used to eliminate confounding variables. Afterwards, least absolute shrinkage and selection operator (LASSO) logistic regression was used to generate the radiomic signature. The diagnostic performance of the radiomic signature was evaluated by the area under the curve (AUC), accuracy, specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

A total of 166 intraparenchymal areas of hyperattenuation from 101 patients were used. The areas of hyperattenuation were randomly allocated to the training and validation cohorts at a ratio of 7:3. The AUC of the radiomic signature was 0.848 (95% confidence interval (CI) 0.780-0.917) in the training cohort and 0.826 (95% CI 0.705-0.948) in the validation cohort. The accuracy of the radiomic signature was 77.6%, with a sensitivity of 76.7%, a specificity of 78.9%, a PPV of 85.2%, and a NPV of 68.2% in the validation cohort.

CONCLUSIONS

The radiomic signature constructed based on initial post-operative nonenhanced CT after mechanical thrombectomy can effectively differentiate IPH from iodinated contrast extravasation.

KEY POINTS

• Radiomic features were extracted from intraparenchymal areas of hyperattenuation on initial post-operative CT scans after mechanical thrombectomy. • The nonenhanced CT-based radiomic signature can differentiate IPH from iodinated contrast extravasation early. • The radiomic signature may help prevent unnecessary rescanning after mechanical thrombectomy, especially in cases where contrast extravasation is highly suggestive.

Cohort study of THRIVE predicting adverse outcomes in acute ischemic stroke of the anterior circulation and posterior circulation after 3 months and 1 year of follow-up

PURPOSE

To evaluate the difference of Totaled Health Risks In Vascular Events (THRIVE) in predicting adverse outcomes in acute ischemic stroke (AIS) of the anterior circulation and posterior circulation at 3-month and 1-year follow-up.

METHODS

A total of 858 patients with AIS were followed up for 3 months and 1 year, and their data prospectively collected. The occurrence of death or moderate to severe disability (modified Rankin Scale ≥ 3 points) was regarded as the endpoint. MedCalc software was used to create the THRIVE receiver operating characteristic curve. The area under the curve (AUC) was calculated to compare the THRIVE scale in predicting adverse outcomes in AIS of the anterior and posterior circulation and compare the differences.

RESULTS

At 3-month follow-up, the AUC of THRIVE was 0.685 (95% CI 0.644-0.724) for AIS of the anterior circulation and 0.709 (95% CI 0.647-0.765) for AIS of the posterior circulation. The area difference between them was 0.0235 (95% CI -0.0728-0.120, P = 0.6330[>0.05]). The AUC of THRIVE for AIS in the anterior circulation at 1 year was 0.701 (95% CI 0.660-0.740), and that for AIS in the posterior circulation at 1 year was 0.747 (95% CI 0.687-0.800). The area difference between them was 0.0458 (95% CI -0.0489-0.140, P = 0.3436 [>0.05]). The difference was not statistically significant.

CONCLUSION

THRIVE can well predict the short-term and long-term adverse prognosis of AIS in the anterior and posterior circulation and has the same predictive effect.

Neuroinflammation in Cerebral Ischemia and Ischemia/Reperfusion Injuries: From Pathophysiology to Therapeutic Strategies

Its increasing incidence has led stroke to be the second leading cause of death worldwide. Despite significant advances in recanalization strategies, patients are still at risk for ischemia/reperfusion injuries in this pathophysiology, in which neuroinflammation is significantly involved. Research has shown that in the acute phase, neuroinflammatory cascades lead to apoptosis, disruption of the blood-brain barrier, cerebral edema, and hemorrhagic transformation, while in later stages, these pathways support tissue repair and functional recovery. The present review discusses the various cell types and the mechanisms through which neuroinflammation contributes to parenchymal injury and tissue repair, as well as therapeutic attempts made in vitro, in animal experiments, and in clinical trials which target neuroinflammation, highlighting future therapeutic perspectives.

Characterization of Subarachnoid Hyperdensities After Thrombectomy for Acute Stroke Using Dual-Energy CT

BACKGROUND AND OBJECTIVES

The presence of post-interventional subarachnoid hyperdensities (SA-HD) is a relatively common finding after mechanical thrombectomy (MT). We aimed to assess the incidence, characteristics, clinical relevance and predictors of SA-HD after MT as categorized through the use of post-interventional Dual Energy-CT (DE-CT).

METHODS

A single-center consecutive series of acute stroke patients treated with MT were retrospectively reviewed. Post-treatment SA-HD were defined as incident extra-axial hyperdensities in a follow-up DE-CT performed within a median of 8 hours after MT. SA-HD were further classified according to their content (isolated contrast extravasation versus blood extravasation) and extension [diffuse (hyperdensities in more than one extraparenchymal compartments) versus non-diffuse]. Adjusted logistic regression models assessed the association of SA-HD with pretreatment and procedural variables and with bad clinical outcome (shift towards worse categories in the ordinal Rankin Scale at 90 days).

RESULTS

SA-HD were observed in 120 (28%) of the 424 included patients (isolated contrast extravasation n=22, blood extravasation n=98). In this group, SA-HD were diffuse in 72 (60%) patients (isolated contrast extravasation n=7, blood extravasation n=65) and non-diffuse in 48 (40%) patients (isolated contrast extravasation n=15, blood extravasation n=33). Diffuse SA-HD were significantly associated with worse clinical outcome in adjusted models (cOR=2.3, 95%CI=1.36-4.00, p=0.002), unlike the specific SA-HD content alone. In contrast with the absence of SA-HD, only the diffuse pattern with blood extravasation was significantly associated with worse clinical outcome (cOR=2.4, 95%CI=1.36-4.15, p=0.002). Diffuse SA-HD patterns were predicted by M2 occlusions, more thrombectomy passes and concurrent parenchymal hematomas.

DISCUSSION

In our cohort of patients imaged within a median of 8 hours after MT, post-interventional SA-HD showed a diffuse pattern in 17% of thrombectomies and were associated with more arduous procedures. Diffuse SA-HD but not local collections of blood or contrast extravasations were associated with an increased risk of poor outcome and death. These findings reinforce the need for improvement in reperfusion strategies.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in individuals with proximal carotid artery territory occlusions treated with mechanical thrombectomy, diffuse post-interventional subarachnoid hyperdensities on imaging 8 hours post-procedure are associated with worse clinical outcomes at 90 days.

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

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

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

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

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

Outcomes of Mechanical Thrombectomy in Patients with Large Diffusion-Weighted Imaging Lesions

Objective

Despite many advancements in endovascular treatment, the benefits of mechanical thrombectomy (MT) in patients with large infarctions remain uncertain due to hemorrhagic complications. Therefore, we aimed to investigate the efficacy and safety of recanalization via MT within 6 hours after stroke in patients with large cerebral infarction volumes (>70 mL).

Methods

We retrospectively reviewed the medical data of 30 patients with large lesions on initial diffusion-weighted imaging (>70 mL) who underwent MT at our institution within 6 hours after stroke onset. Baseline data, recanalization rate, and 3-month clinical outcomes were analyzed. Successful recanalization was defined as a modified treatment in cerebral ischemia score of 2b or 3.

Results

The recanalization rate was 63.3%, and symptomatic intracerebral hemorrhage occurred in six patients (20%). The proportion of patients with modified Rankin Scale (mRS) scores of 0-3 was significantly higher in the recanalization group than in the non-recanalization group (47.4% vs. 9.1%, p=0.049). The mortality rate was higher in the non-recanalization group, this difference was not significant (15.8% vs. 36.4%, p=0.372). In the analysis of 3-month clinical outcomes, only successful recanalization was significantly associated with mRS scores of 0-3 (90% vs. 50%, p=0.049). The odds ratio of recanalization for favorable outcomes (mRS 0-3) was 9.00 (95% confidence interval, 0.95-84.90; p=0.055).

Conclusion

Despite the risk of symptomatic intracerebral hemorrhage, successful recanalization via MT 6 hours after stroke may improve clinical outcomes in patients with large vessel occlusion.

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

PURPOSE OF THE REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Overview of Acute Ischemic Stroke Evaluation and Management

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

Use of quantitative angiographic methods with a data-driven model to evaluate reperfusion status (mTICI) during thrombectomy

PURPOSE

Intra-procedural assessment of reperfusion during mechanical thrombectomy (MT) for emergent large vessel occlusion (LVO) stroke is traditionally based on subjective evaluation of digital subtraction angiography (DSA). However, semi-quantitative diagnostic tools which encode hemodynamic properties in DSAs, such as angiographic parametric imaging (API), exist and may be used for evaluation of reperfusion during MT. The objective of this study was to use data-driven approaches, such as convolutional neural networks (CNNs) with API maps, to automatically assess reperfusion in the neuro-vasculature during MT procedures based on the modified thrombolysis in cerebral infarction (mTICI) scale.

METHODS

DSAs from patients undergoing MTs of anterior circulation LVOs were collected, temporally cropped to isolate late arterial and capillary phases, and quantified using API peak height (PH) maps. PH maps were normalized to reduce injection variability. A CNN was developed, trained, and tested to classify PH maps into 2 outcomes (mTICI 0,1,2a/mTICI 2b,2c,3) or 3 outcomes (mTICI 0,1,2a/mTICI 2b/mTICI 2c,3), respectively. Ensembled networks were used to combine information from multiple views (anteroposterior and lateral).

RESULTS

The study included 383 DSAs. For the 2-outcome classification, average accuracy was 81.0% (95% CI, 79.0-82.9%), and the area under the receiver operating characteristic curve (AUROC) was 0.86 (0.84-0.88). For the 3-outcome classification, average accuracy was 64.0% (62.0-66.0), and AUROC values were 0.85 (0.83-0.87), 0.74 (0.71-0.77), and 0.78 (0.76-0.81) for the mTICI 0,1,2a, mTICI 2b, and mTICI 2c,3 classes, respectively.

CONCLUSION

This study demonstrated the feasibility of using hemodynamic information in API maps with data-driven models to autonomously assess intra-procedural reperfusion during MT.

Development and Testing of Thrombolytics in Stroke

Despite recent advances in recanalization therapy, mechanical thrombectomy will never be a treatment for every ischemic stroke because access to mechanical thrombectomy is still limited in many countries. Moreover, many ischemic strokes are caused by occlusion of cerebral arteries that cannot be reached by intra-arterial catheters. Reperfusion using thrombolytic agents will therefore remain an important therapy for hyperacute ischemic stroke. However, thrombolytic drugs have shown limited efficacy and notable hemorrhagic complication rates, leaving room for improvement. A comprehensive understanding of basic and clinical research pipelines as well as the current status of thrombolytic therapy will help facilitate the development of new thrombolytics. Compared with alteplase, an ideal thrombolytic agent is expected to provide faster reperfusion in more patients; prevent re-occlusions; have higher fibrin specificity for selective activation of clot-bound plasminogen to decrease bleeding complications; be retained in the blood for a longer time to minimize dosage and allow administration as a single bolus; be more resistant to inhibitors; and be less antigenic for repetitive usage. Here, we review the currently available thrombolytics, strategies for the development of new clot-dissolving substances, and the assessment of thrombolytic efficacies in vitro and in vivo.

Alteplase and Adjuvant Therapies for Acute Ischemic Stroke

Acute ischemic stroke (AIS) is a time sensitive medical emergency and a leading cause of morbidity and mortality worldwide. Intravenous (IV) recombinant tissue plasminogen activator (IV alteplase) is currently the only proven effective medication for the treatment of AIS with promising adjuvant medications currently under investigation. Recent advances in endovascular thrombectomy have broadened therapeutic options in specific patient populations, with modern treatment strategies utilizing advanced imaging modalities to extend the window for treatment. In all cases, rapid treatment remains a priority. The future of IV alteplase and the changing standard for treatment of AIS remain unwritten with the increasing evidence for imaging selection for both endovascular thrombectomy and IV alteplase, while novel adjuncts are under investigation. In this article, we review the history of IV alteplase investigations for stroke, evidence for thrombectomy as an adjunct to IV alteplase, and the potential of novel adjuvant therapeutics currently under investigation.

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.

Clinical Trial of the New Stent Retriever Tron FX for both Proximal and Distal Intracranial Large Vessel Occlusions

BACKGROUND

In all of randomized controlled trials of mechanical thrombectomy, the target vessels were proximal. Herein we report a clinical trial of the Tron FX stent retriever, including the smallest size of 2/15 mm for distal intracranial large vessel occlusion (LVO).

OBJECTIVE

Eligible patients presented within 8 h of onset with proximal or distal LVOs, and the Tron FX 4/20 mm or 2/15 mm were used as the first-line device.

METHODS

The primary endpoints were rate of modified Thrombolysis in Cerebral Infarction (mTICI) grade 2a-3 immediately after using Tron FX only, and mortality rate 90 d. We compared the outcomes between sizes 4/20 and 2/15 mm.

RESULTS

The clinical trial was conducted in 50 cases, of which 44% presented with distal LVO and 15 cases were treated using only Tron FX 2/15 mm. The overall rate of mTICI grade 2a-3 was 80.0% (75.8% with Tron FX 4/20 mm, and 86.7% with 2/15 mm), and a 90-day modified Rankin Scale ≤ 2 or improvement of National Institute of Health Stroke Scale after thrombectomy ≥ 10 was achieved in 66.7% of cases (61.3% with Tron FX 4/20 mm, and 80.0% with 2/15 mm). The overall 90-day mortality rate was 8.0%, and symptomatic intracranial hemorrhage within 24 h occurred in 2.0% of cases.

CONCLUSION

In this clinical trial using the Tron FX, which included the size of 2/15 mm for distal LVO, its efficacy was similar and its safety was superior compared with previous studies.