Evolution of endovascular mechanical thrombectomy for acute ischemic stroke

An Evaluation Model for Brain Ischemia Protection in Mice by Low-Intensity Pulsed Ultrasound Stimulation Based on Functional Cortico-Muscular Coupling

(1) Background: Ischemic stroke is a major global public-health concern with complex pathogenesis. Current treatment strategies face challenges. Low-intensity pulsed ultrasound stimulation (LIPUS), a non-invasive neuromodulation technology, shows promise in treating ischemic stroke, yet its underlying mechanisms lack in-depth investigation, especially in quantitative efficacy evaluation. (2) Methods: This study aimed to develop a neuromuscular functional coupling-based dynamic time warping (DTW) model to evaluate LIPUS's neuroprotective effects in a mouse model of ischemic stroke. A bilateral carotid artery occlusion (BCAO) model in mice was established, and LIPUS treatment was given. Time- and frequency-domain analyses of local field potentials (LFPs) and electromyography (EMG) were conducted, and outcomes were quantified using a percentage-based scoring system. (3) Results: The BCAO+LIPUS group scored significantly higher than the BCAO group. (4) Conclusions: This study demonstrated that LIPUS is neuroprotective in BCAO mice and that the DTW-100 assessment evaluation model can quantify the neuroprotective effects of LIPUS.

Neuropsychological outcomes following endovascular clot retrieval and intravenous thrombolysis in ischemic stroke

OBJECTIVES

Cognitive impairment, anxiety, depression, fatigue, and dependence in instrumental activities of daily living (ADL) are common after stroke; however, little is known about how these outcomes may differ following treatment with endovascular clot retrieval (ECR), intravenous tissue plasminogen activator (t-PA), or conservative management.

METHODS

Patients were recruited after acute treatment and invited to participate in an outcome assessment 90-120 days post-stroke. The assessment included a cognitive test battery and several questionnaires. The COVID-19 pandemic led to significant disruptions in recruitment and data collection, and the t-PA and conservative management groups were combined into a standard medical care (SMC) group.

RESULTS

Sixty-two participants were included in the study (ECR = 31, SMC = 31). Mean age was 66.5 (20-86) years, and 35 (56.5%) participants were male. Participants treated with ECR had significantly higher National Institutes of Health Stroke Scale scores at presentation and significantly lower education. After adjusting for stroke severity, premorbid intellectual ability, and age, treatment with ECR was associated with significantly better performances on measures of cognitive screening, visual working memory, and verbal learning and memory. Participants treated with ECR also experienced less fatigue and were more likely to achieve independence in basic and instrumental ADLs. Despite this, cognitive impairment and fatigue were still common among participants treated with ECR and anxiety and depression symptoms were experienced similarly by both groups.

CONCLUSIONS

Cognitive impairment and fatigue were less common but still prevalent following treatment with ECR. This has important practical implications for stroke rehabilitation, and routine assessment of cognition, emotion, and fatigue is recommended for all stroke survivors regardless of stroke treatment and functional outcome.

Dynamic Perviousness Has Predictive Value for Clot Fibrin Content in Acute Ischemic Stroke

Dynamic perviousness is a novel imaging biomarker, with clot density measurements at multiple timepoints to allow longer contrast to thrombus interaction. We investigated the correlations between dynamic perviousness and clot composition in the setting of acute ischemic stroke. Thirty-nine patients with large vessel occlusion (LVO) undergoing mechanical thrombectomy (MT) were analyzed. Patients received a three-phase CT imaging pre-thrombectomy and histopathological analysis of retrieved clots. Clot densities for every phase and change in densities between phases were calculated, leading to four patterns of dynamic perviousness: no contrast uptake, early contrast uptake with and without washout and late uptake. Clots were categorized into three groups based on dominant histologic composition: red blood cell (RBC)-rich, fibrin/platelet-rich and mixed. Clot composition was correlated with dynamic perviousness using the Kruskal-Wallis test and Pearson's correlation analysis. The dynamic perviousness categories showed a significant difference between fibrin-rich clots when compared to RBC-rich plus mixed groups. The uptake without washout category had significantly fewer fibrin clots compared to the uptake with washout (p = 0.036), and nearly significantly fewer fibrin clots when compared to the no uptake category (p = 0.057). Contrast uptake with different patterns of contrast washout showed significant differences of the likelihood for fibrin-rich clots.

Dynamic Perviousness Predicts Revascularization Success in Acute Ischemic Stroke

BACKGROUND

The predictive value of thrombus perviousness in acute ischemic stroke (AIS), as measured by computed tomography (CT), has been intensively studied with conflicting results. In this study, we investigate the predictive potential of the novel concept of dynamic perviousness using three-dimensional (3D) volumetric evaluation of occlusive thrombi.

METHODS

The full thrombus volume in 65 patients with a hyperdense artery sign on non-contrast CT (NCCT), who underwent mechanical thrombectomy (MT), was segmented. Perviousness maps were computed voxel-wise for the entire thrombus volume as thrombus attenuation increase (TAI) between NCCT and CT angiography (CTA) as well as between CTA and late venous phase CT (CTV). Perviousness was analyzed for its association with NIHSS at admission, Thrombolysis In Cerebral Infarction (TICI) score, and number of MT passes.

RESULTS

The mean late-uptake TAI of thrombi with NIHSS scores greater than 21 at admission was approximately 100% higher than for lower scored NIHSS (p between 0.05 and 0.005). Concerning revascularization results, thrombi requiring less than four MT passes had ca. 80% higher group mean late-uptake TAI than clots requiring four or more passes (p = 0.03), and thrombi with TICI score III had ca. 95% higher group mean late-uptake TAI than thrombi with TICI II (p = 0.03). Standard perviousness showed no significant correlation with MT results.

CONCLUSION

Standard thrombus perviousness of 3D clot volume is not associated with revascularization results in AIS. In contrast, dynamic perviousness assessed with a voxel-wise characterization of 3D thrombi volume may be a better predictor of MT outcomes than standard perviousness.

The potential value of histological analysis of thrombi extracted through mechanical thrombectomy during acute ischemic stroke treatment

Studies on thrombus composition in acute stroke or acute myocardial infarction may help elucidate clot etiology and understand reperfusion success or failure. Moreover, such studies may certainly aid in the development of new technologies aimed at retrieving specific subtypes of thrombi; as a matter of fact, thrombus composition is suggested to influence the choice of techniques used during mechanical thrombectomy and plays a role in potential device and thrombus interaction. Over the years, histological analysis on the composition of thrombi causing ischemic stroke has proved to be a powerful tool to set standard prevention and treatment protocols. By isolating clot components, it is possible to provide a more accurate diagnosis and distinguish different stroke subtypes. Studies on histological clot composition support the theory that cryptogenic stroke can have a cardiogenic origin too. Components found in thrombi extracted from stroke patients support the importance of antithrombotic therapy in preventing and treating cerebral ischemia; however, more studies are needed to improve results in all types and subtypes of stroke. Hence, more research is required to further comprehend the role that platelets, fibrin, von Willebrand factor (vWF), and DNA play in relation to mechanical thrombectomy and recombinant tissue plasminogen activator (rtPA) resistance and to overcome certain limitations.

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.

Reperfusion therapy in acute ischemic stroke: dawn of a new era?

Following the success of recent endovascular trials, endovascular therapy has emerged as an exciting addition to the arsenal of clinical management of patients with acute ischemic stroke (AIS). In this paper, we present an extensive overview of intravenous and endovascular reperfusion strategies, recent advances in AIS neurointervention, limitations of various treatment paradigms, and provide insights on imaging-guided reperfusion therapies. A roadmap for imaging guided reperfusion treatment workflow in AIS is also proposed. Both systemic thrombolysis and endovascular treatment have been incorporated into the standard of care in stroke therapy. Further research on advanced imaging-based approaches to select appropriate patients, may widen the time-window for patient selection and would contribute immensely to early thrombolytic strategies, better recanalization rates, and improved clinical outcomes.

Treatment of Acute Ischemic Stroke

Although stroke declined from the third to fifth most common cause of death in the United States, the annual incidence and overall prevalence continue to increase. Since the available US Food and Drug Administration-approved treatment options are time dependent, improving early stroke care may have more of a public health impact than any other phase of care. Timely and efficient stroke treatment should be a priority for emergency department and prehospital providers. This article discusses currently available and emerging treatment options in acute ischemic stroke focusing on the preservation of salvageable brain tissue, minimizing complications, and secondary prevention.

Xingnao Kaiqiao needling method for acute ischemic stroke: a meta-analysis of safety and efficacy

OBJECTIVE:

To evaluate the effectiveness and safety of the Xingnao Kaiqiao needling method for treating acute ischemic stroke.

DATA SOURCES:

We retrieved relevant randomized controlled trials involving Xingnao Kaiqiao acupuncture for treatment of acute ischemic stroke. The China National Knowledge Infrastructure, Weipu Information Resources System, Wanfang Medical Data System, Chinese Biomedical Literature Database, Cochrane Library, and PubMed were searched from June 2006 to March 2016.

DATA SELECTION:

We analyzed randomized and semi-randomized clinical controlled trials that compared Xingnao Kaiqiao acupuncture with various control treatments, such as conventional drugs or other acupuncture therapies, for treatment of acute ischemic stroke. The quality of articles was evaluated according to the Cochrane Handbook for Systematic Reviews of Interventions (Version 5.1), and the study was carried out using Cochrane system assessment methods. RevMan 5.2 was used for the meta-analysis of the included studies.

OUTCOME MEASURES:

The mortality rate, disability rate, activities of daily living (Barthel Index), and clinical efficacy were observed.

RESULTS:

Twelve studies met the inclusion criteria for this review. The meta-analysis showed that between Xingnao Kaiqiao acupuncture and the control treatment, Xingnao Kaiqiao acupuncture reduced the disability rate [risk ratio (RR) = 0.51, 95% confidence interval (CI) = 0.27–0.98, z = 2.03, P < 0.05], elevated the activities of daily living (weighted mean difference = 12.23, 95% CI: 3.66–20.08, z = 2.80, P < 0.005), and had greater clinical efficacy (RR = 1.61, 95% CI: 1.23–2.09, z = 3.53, P < 0.0004). However, there was no significant difference in mortality rate (RR = 0.61, 95% CI: 0.15–2.45, z = 0.70, P > 0.05).

CONCLUSION:

The Xingnao Kaiqiao needling method is effective and safe for acute ischemic stroke. However, there was selective bias in this study, and the likelihood of measurement bias is high. Thus, more high-quality randomized controlled trials are needed to provide reliable evidence of the efficacy and safety of Xingnao Kaiqiao acupuncture in the treatment of acute ischemic stroke.

Manual thromboaspiration technique as a first approach for endovascular stroke treatment: A single-center experience

BACKGROUND

For intracranial large vessel occlusion in acute ischemic stroke (AIS), a high degree of revascularization in the minimal amount of time predicts good outcomes. Recently, different studies have shown that the direct aspiration first pass technique (ADAPT technique) for AIS obtains high recanalization rates, fast interventions and low costs when it works as first attempt. This study retrospectively describes revascularization efficacy, duration of procedure, intra and post-procedural complications, early and after 90-days clinical outcome in a group of patients who underwent ADAPT as the primary endovascular approach, eventually followed by stent retriever thrombectomy, for recanalization of large vessels in the anterior circulation.

MATERIALS AND METHODS

We analyzed clinical and procedural data of patients treated from April 2014 to August 2015. Recanalization was assessed according to the Thrombolysis in Cerebral Infarction score. Clinical outcome was evaluated at discharge and after 3 months (modified Rankin Scale, mRS).

RESULTS

Overall, 71 patients (mean age of 69.7 years) were treated. Sites of occlusion were anterior circulation (including seven tandem extracranial-intracranial occlusions). In 39 patients i.v. rtPA was attempted. Recanalization of the target vessel was obtained in 87.3% of cases whereas direct aspiration alone was successful in 46/71cases (64.8%) with an average puncture-to-revascularization time of 43.1 minutes. Symptomatic intracranial hemorrhage occurred in 7.8% and embolization to new territories in 5.6%. In total, 38 patients (53.5%) had a good outcome at 90 days follow-up.

CONCLUSIONS

In our series, the manual thromboaspiration technique has been shown as fast and safe, with good rates of vessel revascularization in 87.3% of patients and neurological outcome <3 mRS in 53.5% of patients.

(-)-Epigallocatechin Gallate Inhibits Asymmetric Dimethylarginine-Induced Injury in Human Brain Microvascular Endothelial Cells

(-)-Epigallocatechin gallate (EGCG) is the main polyphenol component of green tea (leaves of the Camellia sinensis plant). EGCG has been reported to protect human brain microvascular endothelial cells (HBMECs) against injury in several models. However, the exact mechanism is still unclear. In the current study we found that EGCG protected against asymmetric dimethylarginine (ADMA)-induced HBMEC injury, and inhibited ADMA-induced reactive oxygen species production and malondialdehyde expression. At the same time, we found that pretreatment with EGCG attenuated the upregulation of Bax and the downregulation of Bcl-2, thus confirming the cellular protective properties of EGCG against ADMA-induced apoptosis. Furthermore, we found that EGCG inhibited ADMA-induced phosphorylation of ERK1/2 and p-38, whose inhibitors relieved HBMEC injury. In conclusion, EGCG can protect against ADMA-induced HBMEC injury via the ERK1/2 and p38 MAPK pathways, which are involved in the underlying mechanisms of HBMEC injury in cerebral infarction.

Thromboaspiration technique as first approach for endovascular treatment of acute ischemic stroke: initial experience at nine Italian stroke centers

BACKGROUND AND PURPOSE

Aspiration thrombectomy of large vessel occlusions has made a comeback among recanalization techniques thanks to recent advances in catheter technology resulting in faster recanalization and promising clinical results when used either alone or as an adjunct to stent retriever. This multicenter retrospective study reports angiographic data, complications, and clinical outcome in patients treated with aspiration thrombectomy as the first-line option.

MATERIALS AND METHODS

We analysed the clinical and procedural data of patients treated from January 2014 to March 2015. Recanalization was assessed according to the Thrombolysis in Cerebral Infarction score. Clinical outcome was evaluated at discharge and after 3 months.

RESULTS

Overall, 152 patients (mean age 68 years) were treated. Sites of occlusion were 90.8% anterior circulation (including 16.4% tandem extracranial/intracranial occlusions) and 9.2% basilar artery. In 79 patients administration of intravenous tissue plasminogen activator was attempted. Recanalization of the target vessel was obtained in 115/152 cases (75.6%) whereas direct aspiration alone was successful in 83/152 cases (54.6%) with an average puncture to revascularization time of 44.67 min. Symptomatic intracranial hemorrhage occurred in 7.8% and embolization to new territories in 1.9%. 77 patients (50.6%) had a good outcome at 90-day follow-up: 55/96 in the direct aspiration alone group and 22/56 in the aspiration-stent retriever group.

CONCLUSIONS

Direct aspiration thrombectomy appears a feasible technique with good revascularization results achieved in more than half the patients. In light of the self-reported data, inhomogeneous patient selection, absence of a core imaging laboratory, and a non-standardized approach, the results should be validated in a larger trial.

Thrombus Permeability Is Associated With Improved Functional Outcome and Recanalization in Patients With Ischemic Stroke

BACKGROUND AND PURPOSE

Preclinical studies showed that thrombi can be permeable and may, therefore, allow for residual blood flow in occluded arteries of patients having acute ischemic stroke. This perviousness may increase tissue oxygenation, improve thrombus dissolution, and augment intra-arterial treatment success. We hypothesize that the combination of computed tomographic angiography and noncontrast computed tomography imaging allows measurement of contrast agent penetrating a permeable thrombus, and it is associated with improved outcome.

METHODS

Thrombus and contralateral artery attenuations in noncontrast computed tomography and computed tomographic angiography images were measured in 184 Multicenter Randomized Clinical trial of Endovascular treatment of acute ischemic stroke in the Netherlands (MR CLEAN) patients with thin-slice images. Two quantitative estimators of the thrombus permeability were introduced: computed tomographic angiography attenuation increase (Δ) and thrombus void fraction (ε). Patients were dichotomized as having a pervious or impervious thrombus and associated with outcome, recanalization, and final infarct volume.

RESULTS

Patients with Δ≥10.9 HU (n=81 [44%]) and ε≥6.5% (n=77 [42%]) were classified as having a pervious thrombus. These patients were 3.2 (95% confidence interval, 1.7-6.4) times more likely to have a favorable outcome, and 2.5 (95% confidence interval, 1.3-4.8) times more likely to recanalyze, for Δ based classification, and similarly for ε. These odds ratios were independent from intravenous or intra-arterial treatment. Final infarct volume was negatively correlated with both perviousness estimates (correlation coefficient, -0.39 for Δ and -0.40 for ε).

CONCLUSIONS

This study shows that simultaneous measurement of thrombus attenuation in noncontrast computed tomography and computed tomographic angiography allows for quantification of thrombus perviousness. Thrombus perviousness is strongly associated with improved functional outcome, smaller final infarct volume, and higher recanalization rate.

A Novel Canine Model of Acute Vertebral Artery Occlusion

Background

The extended time window and theoretic reduction in hemorrhage make mechanical strategies an attractive approach for the treatment of patients with ischemic stroke. However, a limited availability of suitable animal models of cerebrovascular thrombosis has hampered the study of novel endovascular interventions. The aim of the present study was to develop a new technique for site-specific placement of a thrombus in a canine model that would allow for the evaluation of mechanical thrombectomy and clot retrieval methods and the visualization of thrombus dislocation or fragmentation during angiographic manipulation.

Methods

Angiography and embolization with a preformed thrombus were performed in 12 canines. Under fluoroscopic guidance, an embolism protection device (EPD) was anchored to the middle segment of the left vertebral artery (VA) via the left femoral arterial sheath. A preformed radiopaque clot was injected through the guide catheter into the left VA, via the contralateral femoral artery, proximal to the EPD. After 15 min of occlusion, the EPD was removed and persistent occlusion of the VA was documented angiographically.

Results

Angiography performed during the observation period confirmed the persistence of VA occlusion in each case, and displacement of the radiopaque clots did not occur during the 3-hour observation period. The technique allowed selective embolization of targeted vessels without thrombus fragmentation.

Conclusion

This study demonstrates, for the first time, a canine model of post-circulation embolism induced by autologous blood clot placement. This model can be rapidly formed and easily operated, and the site of thrombosis can be readily controlled.

Endovascular vs medical management of acute ischemic stroke

OBJECTIVE

To compare the outcomes between endovascular and medical management of acute ischemic stroke in recent randomized controlled trials (RCT).

METHODS

A systematic literature review was performed, and multicenter, prospective RCTs published from January 1, 2013, to May 1, 2015, directly comparing endovascular therapy to medical management for patients with acute ischemic stroke were included. Meta-analyses of modified Rankin Scale (mRS) and mortality at 90 days and symptomatic intracranial hemorrhage (sICH) for endovascular therapy and medical management were performed.

RESULTS

Eight multicenter, prospective RCTs (Interventional Management of Stroke [IMS] III, Local Versus Systemic Thrombolysis for Acute Ischemic Stroke [SYNTHESIS] Expansion, Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy [MR RESCUE], Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands [MR CLEAN], Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness [ESCAPE], Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial [EXTEND-IA], Solitaire With the Intention For Thrombectomy as Primary Endovascular Treatment [SWIFT PRIME], and Endovascular Revascularization With Solitaire Device Versus Best Medical Therapy in Anterior Circulation Stroke Within 8 Hours [REVASCAT]) comprising 2,423 patients were included. Meta-analysis of pooled data demonstrated functional independence (mRS 0-2) at 90 days in favor of endovascular therapy (odds ratio [OR] = 1.71; p = 0.005). Subgroup analysis of the 6 trials with large vessel occlusion (LVO) criteria also demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.23; p < 0.00001). Subgroup analysis of the 5 trials that primarily utilized stent retriever devices (≥70%) in the intervention arm demonstrated functional independence at 90 days in favor of endovascular therapy (OR = 2.39; p < 0.00001). No difference was found for mortality at 90 days and sICH between endovascular therapy and medical management in all analyses and subgroup analyses.

CONCLUSIONS

This meta-analysis provides strong evidence that endovascular intervention combined with medical management, including IV tissue plasminogen activator for eligible patients, improves the outcomes of appropriately selected patients with acute ischemic stroke in the setting of LVO.

Efficacy and Safety of Mechanical Thrombectomy in Treating Acute Ischemic Stroke: A Meta Analysis

OBJECTIVES

Mechanical thrombectomy (MT) is a promising treatment for acute ischemic stroke (AIS). But the results of completed trials were contradictory. Hence, we performed a meta-analysis to evaluate the efficacy and safety of MT in treating AIS.

METHODS

Literatures were searched in the databases including Pubmed, Cochrane Library, Web of Science and Ovid-SP. The bias and quality of publications with randomized controlled trials (RCTs) were assessed with the Cochrane collaboration's tool for assessing risk of bias.

RESULTS

Totally 16 publications matched the inclusion criteria, including seven independent RCTs and 2043 AIS patients. The results showed that the recanalization rate and the modified Rankin score of 0-2 at 90 days after treatment were better in MT combining standard care group, but the mortality had no significant difference, even the incidence of intracerebral hemorrhage during follow-up period was worse, as compared with standard care group.

CONCLUSION

MT combining standard care would be an effective and promising treatment for AIS patients according to the present study.

Residual Thromboembolic Material in Cerebral Arteries after Endovascular Stroke Therapy Can Be Identified by Dual-Energy CT

BACKGROUND AND PURPOSE

Dual-energy CT features the opportunity to differentiate among up to 3 different materials because the absorption of x-rays depends on the applied tube voltage and the atomic number of the material. For example, it is possible to distinguish between blood-brain barrier disruption and an intracerebral hemorrhage following treatment for a stroke. The aim of this study was to evaluate whether dual-energy CT is capable of distinguishing intra-arterial contrast agent from residually clotted vessels immediately after endovascular stroke therapy.

MATERIALS AND METHODS

Sixteen patients (9 women, 7 men; mean age, 63.6 ± 13.09 years) were examined. Measurements were made on the postinterventional dual-energy CT virtual noncontrast, iodine map, and "weighted" brain window (weighted dual-energy) series. Postinterventional conventional angiography was used as the criterion standard method.

RESULTS

A residual clot was found in 10 patients. On the virtual noncontrast series, the Hounsfield attenuation of the clotted arteries was higher than that in the corresponding perfused contralateral arteries (53.72 ± 9.42 HU versus 41.64 ± 7.87 HU; P < .05). The latter had higher absorption values on the weighted dual-energy series than on the virtual noncontrast series (49.37 ± 7.44 HU versus 41.64 ± 7.87 HU; P < .05). The sensitivity for the detection of a residual clot was 90%; the specificity was 83.3%, and the accuracy was 87.5%. Interrater agreement was good (κ = 0.733).

CONCLUSIONS

Dual-energy CT may be valuable in the detection of clot persistence or early re-thrombosis without the necessity of additional contrast administration. However, its relevance for the prediction of outcomes remains to be determined in further studies.

Endovascular Mechanical Thrombectomy for Acute Ischemic Stroke: A New Standard of Care

The treatment of acute ischemic stroke (AIS) in the setting of intracranial large artery occlusion (LAO) with intravenous tissue plasminogen activator (IV-tPA) is associated with low rates of recanalization and high rates of neurological morbidity and functional dependence. Endovascular intervention, particularly mechanical thrombectomy, is a promising therapeutic adjunct to IV-tPA for the treatment of acute LAO. However, until recently, its efficacy has been controversial. In this brief review, we analyze the criticisms of three negative randomized controlled trials (RCT) of endovascular stroke treatment and evaluate the results from seven positive endovascular stroke RCTs that have recently been presented or published. IMS III, MR RESCUE, and SYTHESIS Expansion were three RCTs that failed to show a benefit from endovascular stroke therapy. Major criticisms of these studies included a lack of routine screening for LAO, resulting in the selection of AIS patients without LAO for endovascular intervention, and a low utilization rate of modern endovascular thrombectomy devices, leading to substandard rates of successful recanalization. MR CLEAN was the first phase III RCT to show a significant clinical benefit from endovascular stroke therapy. The dissemination of its findings elicited a cascade of positive results from, to date, six additional endovascular stroke RCTs, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, THERAPY, and THRACE, which were halted prematurely for efficacy. The cumulative evidence from these studies shows an overwhelming benefit from the endovascular treatment of acute LAO, therefore effectively establishing a new standard of care for the management of AIS.