A meta-analysis of observational intra-arterial stroke therapy studies using the Merci device, Penumbra system, and retrievable stents

Biomarkers of Technical Success After Embolectomy for Acute Stroke

PURPOSE OF THE REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Guidelines for the Early Management of Patients With Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

Background and Purpose- The purpose of these guidelines is to provide an up-to-date comprehensive set of recommendations in a single document for clinicians caring for adult patients with acute arterial ischemic stroke. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators. These guidelines supersede the 2013 Acute Ischemic Stroke (AIS) Guidelines and are an update of the 2018 AIS Guidelines. Methods- Members of the writing group were appointed by the American Heart Association (AHA) Stroke Council's Scientific Statements Oversight Committee, representing various areas of medical expertise. Members were not allowed to participate in discussions or to vote on topics relevant to their relations with industry. An update of the 2013 AIS Guidelines was originally published in January 2018. This guideline was approved by the AHA Science Advisory and Coordinating Committee and the AHA Executive Committee. In April 2018, a revision to these guidelines, deleting some recommendations, was published online by the AHA. The writing group was asked review the original document and revise if appropriate. In June 2018, the writing group submitted a document with minor changes and with inclusion of important newly published randomized controlled trials with >100 participants and clinical outcomes at least 90 days after AIS. The document was sent to 14 peer reviewers. The writing group evaluated the peer reviewers' comments and revised when appropriate. The current final document was approved by all members of the writing group except when relationships with industry precluded members from voting and by the governing bodies of the AHA. These guidelines use the American College of Cardiology/AHA 2015 Class of Recommendations and Level of Evidence and the new AHA guidelines format. Results- These guidelines detail prehospital care, urgent and emergency evaluation and treatment with intravenous and intra-arterial therapies, and in-hospital management, including secondary prevention measures that are appropriately instituted within the first 2 weeks. The guidelines support the overarching concept of stroke systems of care in both the prehospital and hospital settings. Conclusions- These guidelines provide general recommendations based on the currently available evidence to guide clinicians caring for adult patients with acute arterial ischemic stroke. In many instances, however, only limited data exist demonstrating the urgent need for continued research on treatment of acute ischemic stroke.

The Effects of Balloon-Guide Catheters on Outcomes after Mechanical Thrombectomy in Acute Ischemic Strokes : A Meta-Analysis

Objective

Mechanical thrombectomies with balloon-guide catheters (BGC) are thought to improve successful recanalization rates and to decrease the incidence of distal emboli compared to thrombectomies without BGC. We aimed to assess the effects of BGC on the outcomes of mechanical thrombectomy in acute ischemic strokes.

Methods

Studies from PubMed, EMBASE, and the Cochrane library database from January 2010 to February 2018 were reviewed. Random effect model for meta-analysis was used. Analyses such as meta-regression and the “trim-and-fill” method were additionally carried out.

Results

A total of seven articles involving 2223 patients were analyzed. Mechanical thrombectomy with BGC was associated with higher rates of successful recanalization (odds ratio [OR], 1.632; 95% confidence interval [CI], 1.293–2.059). BGC did not significantly decrease distal emboli, both before (OR, 0.404; 95% CI, 0.108–1.505) and after correcting for bias (adjusted OR, 1.165; 95% CI, 0.310–4.382). Good outcomes were observed more frequently in the BGC group (OR, 1.886; 95% CI, 1.564–2.273). Symptomatic intracranial hemorrhage and mortality did not differ significantly with BGC use.

Conclusion

Our meta-analysis demonstrates that BGC enhance recanalization rates. However, BGC use did not decrease distal emboli after mechanical thrombectomies. This should be interpreted with caution due to possible publication bias and heterogeneity. Additional meta-analyses based on individual patient data are needed to clarify the role of BGC in mechanical thrombectomies.

Experience of the New FlowGate2 Device as a Balloon Guide Catheter for Ischemic Stroke Intervention

BACKGROUND

We report the experience of the FlowGate² (FG2) as a new balloon guide catheter in endovascular stroke intervention.

METHODS

We evaluated the various outcomes and complications of patients with intracranial large artery occlusion undergoing endovascular stroke intervention with FG2 at our center. Baseline characteristics (failure rate of device application, sex, age, risk factors, arterial occlusion sites, and time intervals) were reviewed. Outcomes were evaluated according to National Institutes of Health Stroke Scale score, modified Rankin Scale (mRS) score, number of stent passages required, and Thrombolysis in Cerebral Infarction score. The incidence of hemorrhage, vessel damage, distal emboli, and mortality rate were evaluated as indicators of complications.

RESULTS

Overall, 70 patients were enrolled, except the 2 patients with application failure of FG2. Seventy patients with a median age of 69 years were treated with FG2. Arterial occlusion involved the M1 (50%) and M2 (14.3%) segments, internal carotid artery (25.7%), and posterior circulation (10%). Median value of mRS at 90 days was 2.8, and 37 patients (52.8%) had a mRS score ≤2. The recanalization rate in patients with a Thrombolysis in Cerebral Infarction score of 2b or 3 was 91.4%. The hemorrhage rate was 5.7%, but none were symptomatic. In terms of complications, distal emboli occurred in 4.3% of cases.

CONCLUSIONS

Endovascular stroke intervention with the FG2 is safe and effective with good accessibility and less occurrence of distal emboli. Its trackability, stability, and luminal size make the FG2 suitable for stroke intervention.

Need for rescue treatment and its implication: stent retriever versus contact aspiration thrombectomy

Backgroud

The need for rescue treatment (RT) may differ depending on first-line modality (stent retriever (SR) or contact aspiration (CA)) in endovascular thrombectomy (EVT). We aimed to investigate whether the type of first-line modality in EVT was associated with the need for RT.

Methods

We identified all patients who underwent EVT for anterior circulation large-vessel occlusion from prospectively maintained registries of 17 stroke centers. Patients were dichotomized into SR-first and CA-first. RT involved switching to the other device, balloon angioplasty, permanent stenting, thrombolytics, glycoprotein IIb/IIIa antagonist, or any combination of these. We compared clinical characteristics, procedural details, and final recanalization rate between the two groups and assessed whether first-line modality type was associated with RT requirement and if this affected clinical outcome.

Results

A total of 955 patients underwent EVT using either SR-first (n=526) or CA-first (n=429). No difference occurred in the final recanalization rate between SR-first (82.1%) and CA-first (80.2%). However, recanalization with the first-line modality alone and first-pass recanalization rates were significantly higher in SR-first than in CA-first. CA-first had more device passes and higher RT rate. The RT group had significantly longer puncture-to-recanalization time (93±48 min versus 53±28 min). After adjustment, CA-first remained associated with RT (OR, 1.367; 95% CI, 1.019 to 1.834). RT was negatively associated with good outcome (OR, 0.597; 95% CI, 0.410 to 0.870).

Conclusion

CA was associated with requiring RT, while recanalization with first-line modality alone and first-pass recanalization rates were higher with SR. RT was negatively associated with good outcome.

Influence of Anesthesia Type on Outcomes after Endovascular Treatment in Acute Ischemic Stroke: Meta-Analysis

PURPOSE

To assess clinical and angiographic outcomes after endovascular treatment (EVT) in ischemic stroke patients according to anesthesia types (general anesthesia vs. conscious sedation).

MATERIALS AND METHODS

A systematic literature review through an online data base between January 1990 and September 2017 was performed. A fixed effect model was used in cases of <50% heterogeneity. The primary outcomes were good clinical outcome at the 3-month follow-up and successful recanalization. A meta-regression analysis was done to estimate primary outcomes of log odds ratio (OR) on onset-to-puncture time (OTP) differences. Publication bias was determined using Begg's funnel plot and additional the Trim and Fill method.

RESULTS

Sixteen articles including 2,662 patients (general anesthesia, n=1,275; conscious sedation, n=1,387) were included. General anesthesia significantly decreased good outcomes than conscious sedation (OR, 0.564; 95% confidence interval [CI], 0.354-0.899). However, outcomes did not differ significantly in randomized controlled trials (RCTs; OR, 1.101; 95% CI, 0.395-3.071). Anesthesia type was not associated with successful recanalization (OR, 0.985; 95% CI, 0.787-1.233). General anesthesia increased the risk of mortality (OR, 1.532; 95% CI, 1.187-1.976) and pneumonia (OR, 1.613; 95% CI, 1.172-2.221), but not symptomatic intracranial hemorrhage (OR, 1.125; 95% CI, 0.767-1.652). The meta-regression analysis showed no linear relationship between OTP differences and log OR of good outcome (coefficient, 0.0004; P=0.95) or successful recanalization (coefficient, 0.0005; P=0.94), respectively.

CONCLUSION

General anesthesia seemed to be associated with adverse clinical outcome after EVT. However, its efficacy was not demonstrated in RCTs. Successful recanalization did not differ according to anesthesia type. Studies using individual patient data based on further RCTs are necessary to elucidate anesthesia effect on procedural and clinical outcomes.

Meta-Analysis of Endovascular Treatment for Acute M2 Occlusion

Objective

Endovascular treatment (EVT) outcomes for acute M2 segment of middle cerebral artery occlusion remains unclear because most results are obtained from patients with large artery occlusion in the anterior circulation. The objective of this study was to assess procedural outcomes for acute M2 occlusion and compare outcomes according to thrombus location (M1 vs. M2).

Methods

A systematic review was performed for online literature published from January 2004 to December 2016. Primary outcome was successful recanalization rate and symptomatic intracranial hemorrhage (S-ICH) after the procedure. A fixed effect model was used if heterogeneity was less than 50%.

Results

Eight articles were included. EVT showed successful recanalization rate of 69.1% (95% confidence interval [CI], 54.9–80.4%) and S-ICH rate of 6.1% (95% CI, 4.5–8.3%). The rates of good clinical outcome at 3 months and mortality were 59.4% (95% CI, 49.9–68.2%) and 14.9% (95% CI, 11.4–19.3%), respectively. According to thrombus location (M1 vs. M2), successful recanalization (odds ratio [OR], 1.539; 95% CI, 0.293–8.092; p=0.610) and S-ICH (OR, 1.313; 95% CI, 0.603–2.861; p=0.493) did not differ significantly. Good clinical outcome was more evident in M2 occlusion after EVT than that in M1 occlusion (OR, 1.639; 95% CI, 1.135–2.368; p=0.008). However, mortality did not differ significantly according to thrombus location (OR, 0.788; 95% CI, 0.486–1.276; p=0.332).

Conclusion

EVT seems to be technically feasible for acute M2 occlusion. Direct comparative studies between EVT and medical treatment are needed further to find specific beneficiary group after EVT in patient with M2 occlusion.

Endovascular Treatment with Intravenous Thrombolysis versus Endovascular Treatment Alone for Acute Anterior Circulation Stroke : A Meta-Analysis of Observational Studies

Objective

The aim of this study was to determine outcome of ischemic stroke patients in the anterior circulation treated with endovascular treatment (EVT) with intravenous thrombolysis (IVT) versus EVT alone group.

Methods

A systemic literature review was performed using online database from January 2004 to January 2017. Primary outcomes were successful recanalization seen on finial angiography and good outcome at three months. Secondary outcomes were mortality and the development of symptomatic intracranial hemorrhage (S-ICH) after the procedure. A fixed effect model was used when heterogeneity was less than 50%. Egger’s regression test was used to assess publication bias.

Results

Five studies were included for final analysis. Between EVT with IVT and EVT alone group, successful recanalization (odds ratio [OR] 1.467, p=0.216), good clinical outcome at three months (OR 1.199, p=0.385), mortality (OR 0.776, p=0.371), and S-ICH (OR 1.820, p=0.280) did not differ significantly. Egger’s regression intercept with 95% confidence interval (CI) was 1.99 (95% CI -2.91 to 6.89) in successful recanalization and -0.27 (95% CI -6.35 to 5.80) in good clinical outcome, respectively.

Conclusion

The two treatment modalities, EVT with IVT and EVT alone, could be comparable in treating acute anterior circulation stroke. Studies to find specific beneficiary group for EVT alone, without primary IVT, are needed further.

2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

The purpose of these guidelines is to provide an up-to-date comprehensive set of recommendations for clinicians caring for adult patients with acute arterial ischemic stroke in a single document. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators. These guidelines supersede the 2013 guidelines and subsequent updates.

METHODS

Members of the writing group were appointed by the American Heart Association Stroke Council's Scientific Statements Oversight Committee, representing various areas of medical expertise. Strict adherence to the American Heart Association conflict of interest policy was maintained. Members were not allowed to participate in discussions or to vote on topics relevant to their relations with industry. The members of the writing group unanimously approved all recommendations except when relations with industry precluded members voting. Prerelease review of the draft guideline was performed by 4 expert peer reviewers and by the members of the Stroke Council's Scientific Statements Oversight Committee and Stroke Council Leadership Committee. These guidelines use the American College of Cardiology/American Heart Association 2015 Class of Recommendations and Levels of Evidence and the new American Heart Association guidelines format.

RESULTS

These guidelines detail prehospital care, urgent and emergency evaluation and treatment with intravenous and intra-arterial therapies, and in-hospital management, including secondary prevention measures that are appropriately instituted within the first 2 weeks. The guidelines support the overarching concept of stroke systems of care in both the prehospital and hospital settings.

CONCLUSIONS

These guidelines are based on the best evidence currently available. In many instances, however, only limited data exist demonstrating the urgent need for continued research on treatment of acute ischemic stroke.

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.

Primary Endovascular Treatment of Acute Ischemic Stroke Using Stent Retrievers: Initial Egyptian Experience

BACKGROUND

Several mechanical thrombectomy (MT) devices have been designed with the goal of improving the recanalization rates of major intracranial artery occlusions.

OBJECTIVE

In this single-center experience, we analyzed the acute ischemic stroke (AIS) treatment with Primary MT; safety and efficacy and clinical results in our patients with large vessel occlusion (LVO).

METHODS

During a five-year period (from September 2011 to July 2016), out of 996 patients who presented to our center with a diagnosis of AIS, 113 (11.4%) patients (55 men and 58 women) underwent primary mechanical recanalization within three hours from onset of signs and symptoms for anterior and 12 hours for posterior circulation (with computer tomography angiography/perfusion ELVO). Successful recanalization (thrombolysis in cerebral infarction 2b-3), good outcome (modified Rankin scale score 0-2) and overall mortality rate, and symptomatic intracranial hemorrhage [sICH: parenchymal hematoma Type 1 or Type 2; National Institutes of Health Stroke Scale (NIHSS) score increment ≥4 points] were prospectively assessed.

RESULTS

The mean age of the patients was 62 ± 11.73 years, with a baseline mean admission NIHSS score of 16.7 ± 3.2. The mean time from onset to puncture (time to treatment) was 208.55 ± 53.49. Successful recanalization was achieved in 104 (92%) cases. Good outcome was observed in 89 (78.8%) patients, and mortality was 11.5% (n = 13). sICH occurred in five (4.4%) patients.

CONCLUSION

MT, within the first 4.5 hours, as primary treatment of acute LVO stroke provides high rate of recanalization and favorable clinical outcomes with low procedural complications.

Clinical and Angiographic Outcomes with the Combined Local Aspiration and Retriever in the North American Solitaire Stent-Retriever Acute Stroke (NASA) Registry

Background

Various techniques are used to enhance the results of mechanical thrombectomy with stent-retrievers, including proximal arrest with balloon guide catheter (BGC), conventional large bore proximal catheter (CGC), or in combination with local aspiration through a large-bore catheter positioned at the clot interface (Aspiration-Retriever Technique for Stroke [ARTS]). We evaluated the impact of ARTS in the North American Solitaire Acute Stroke (NASA) registry.

Summary

Data on the use of the aspiration technique were available for 285 anterior circulation patients, of which 29 underwent ARTS technique, 131 CGC, and 125 BGC. Baseline demographics were comparable, except that ARTS patients are less likely to have hypertension or atrial fibrillation. The ARTS group had more ICA occlusions (41.4 vs. 22% in the BGC, p = 0.04 and 26% in CGC, p = 0.1) and less MCA/M1 occlusions (44.8 vs. 68% in BGC and 62% in CGC). Time from arterial puncture to reperfusion or end of procedure with ARTS was shorter than with CGC (54 vs. 91 min, p = 0.001) and was comparable to the BGC time (54 vs. 67, p = 0.11). Final degree of reperfusion was comparable among the groups (TICI [modified Thrombolysis in Cerebral Infarction] score 2b or higher was 72 vs. 70% for CGC vs. 78% for BGC). Procedural complications, mortality, and good clinical outcome at 90 days were similar between the groups.

Key Messages

The ARTS mechanical thrombectomy in acute ischemic stroke patients appears to yield better results as compared to the use of CGCs with no significant difference when compared to BGC. This early ARTS technique NASA registry data are limited by the earlier generation distal large bore catheters and small sample size. Future studies should focus on the comparison of ARTS and BGC techniques.

Effect of Retrievable Stent Size on Endovascular Treatment of Acute Ischemic Stroke: A Multicenter Study

BACKGROUND AND PURPOSE

In clinical practice, stent diameter is one of the variable properties important for endovascular treatment. A consensus guideline for stent retriever size selection has yet to be established. The aim of this study was to investigate the effects of different diameters of Solitaire retrievers on outcomes.

MATERIALS AND METHODS

Of 628 patients enrolled from the Endovascular Treatment for Acute Anterior Circulation Ischemic Stroke Registry, 256 were treated with the Solitaire 4-mm device and 372, with the 6-mm device. We matched patients treated with the 2 stent sizes using propensity score analysis. The successful outcome was reperfusion as measured by the modified Thrombolysis in Cerebral Infarction score immediately postprocedure and the dichotomized modified Rankin Scale score at 90 days. Symptomatic intracerebral hemorrhage and in-hospital mortality were also recorded.

RESULTS

After propensity score analysis, group outcomes did not differ. In addition, in patients with atherosclerosis-related occlusion, a higher reperfusion rate (P = .021) was observed in the Solitaire 4 group, as well as a shorter time interval (P = .002) and fewer passes (P = .025). Independent predictors of successful reperfusion in patients with atherosclerotic disease on logistic analysis were the small stent (OR, 3.217; 95% CI, 1.129-9.162; P = .029) and the propensity score acting as a covariate (OR, 52.84; 95% CI, 3.468-805.018; P = .004).

CONCLUSIONS

We found no evidence of a differential effect of intra-arterial therapy based on the size of Solitaire retrievers. In patients with atherosclerotic disease, favorable reperfusion was associated with deployment of a small stent.

Intra-arterial mechanical thrombectomy stent retrievers and aspiration devices in the treatment of acute ischaemic stroke: A systematic review and meta-analysis with trial sequential analysis

Purpose

Intra-arterial mechanical thrombectomy combined with appropriate patient selection (image-based selection of acute ischaemic stroke patients with large artery occlusion) yields improved clinical outcomes. We conducted a systematic review and meta-analysis, with trial sequential analysis to understand the benefits, risks and impact of new trials reporting in 2016 on the magnitude/certainty of the estimates for clinical effectiveness and safety of mechanical thrombectomy.

Method

Random effects' models were conducted of randomised clinical trials comparing mechanical thrombectomy (stent retriever or aspiration devices) with/without adjuvant intravenous thrombolysis with intravenous thrombolysis and other forms of best medical/supportive care in the treatment of acute ischaemic stroke. Study inclusion and risk of bias were assessed independently by two reviewers. Functional independence (modified Rankin Scale 0-2) and mortality at 90 days, including symptomatic intracranial haemorrhage rate were extracted. Trial sequential analysis established the strength of the evidence derived from the meta-analyses.

Findings

Eight trials of mechanical thrombectomy with a total sample size of 1841 (916 patients treated with mechanical thrombectomy and 925 treated without mechanical thrombectomy) fulfilled review inclusion criteria. The three most recent trials more precisely defined the effectiveness of mechanical thrombectomy (modified Rankin Scale 0 to 2; OR = 2.07, 95% CI = 1.70 to 2.51 based on data from eight trials versus OR = 2.39, 95% CI = 1.88 to 3.04 based on data from five trials). Meta-analyses showed no effect on mortality (OR = 0.81, 95% CI = 0.61 to 1.07) or symptomatic intracranial haemorrhage (OR = 1.22, 95% CI = 0.80 to 1.85) as found in analysis of first five trials. Trial sequential analysis indicated that the information size requirement was fulfilled to conclude the evidence for mechanical thrombectomy is robust.

Discussion

The impact of three recent trials on effectiveness and safety of mechanical thrombectomy was a more precise pooled effect size for functional independence. Trial sequential analysis demonstrated sufficient evidence for effectiveness and safety of mechanical thrombectomy.

Conclusion

No further trials of mechanical thrombectomy versus no mechanical thrombectomy are indicated to establish clinical effectiveness. Uncertainty remains as to whether mechanical thrombectomy reduces mortality or increases risk of symptomatic intracranial haemorrhage.

Comparison of a Balloon Guide Catheter and a Non-Balloon Guide Catheter for Mechanical Thrombectomy

Purpose To evaluate the effectiveness of mechanical thrombectomy with the use of a stent retriever in acute ischemic stroke, performed by using a balloon guide catheter or non-balloon guide catheter. Materials and Methods In accordance with the institutional review board approval obtained at the two participating institutions, retrospective analysis was performed in 183 consecutive patients treated between 2013 and 2014 for occlusions in the middle cerebral artery or carotid terminus by using a stent retriever with a balloon guide catheter (n = 102) at one center and a non-balloon guide catheter (n = 81) at the other center. Data on procedure duration, number of passes, angiographic findings, type of stent retriever used, and expertise of the operators were collected. Successful recanalization was defined as grade 3 or 2b modified Treatment in Cerebral Ischemia recanalization accomplished in up to three passes. Univariate and multivariate subgroup analyses were conducted to control for the confounding variables of prior thrombolysis, location of occlusion, and operator expertise. Results Successful recanalization with the balloon guide catheter was achieved in 89.2% of thrombectomies (91 of 102) versus 67.9% (55 of 81) achieved with the non-balloon guide catheter (P = .0004). The one-pass thrombectomy rate with the balloon guide catheter was significantly higher than for that with the non-balloon guide catheter (63.7% [65 of 102] vs 35.8% [29 of 81], respectively; P = .001). The procedure duration was significantly shorter by using the balloon guide catheter than the non-balloon guide catheter (median, 20.5 minutes vs 41.0 minutes, respectively; P < .0001). Conclusion The effectiveness of mechanical thrombectomy with stent retrievers in acute ischemic stroke in the anterior circulation in terms of angiographic results and procedure duration was improved when performed in combination with the balloon guide catheter. (©) RSNA, 2016.

Catheter-based interventions for acute ischaemic stroke

Catheter-based interventions for acute ischaemic stroke currently include clot removal (usually from the medial cerebral artery) with modern stent-retrievers and in one of five patients (who have simultaneous or stand-alone internal carotid occlusion) also extracranial carotid intervention. Several recently published randomized trials clearly demonstrated superiority of catheter-based interventions (with or without bridging thrombolysis) over best medical therapy alone. The healthcare systems should adopt the new strategies for acute stroke treatment (including fast track to interventional lab) to offer the benefits to all suitable acute stroke patients.

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.

Functional outcomes and recanalization rates of stent retrievers in acute ischaemic stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Intra-arterial therapy for acute ischaemic stroke has evolved rapidly in the last few years. Stent retrievers have now replaced 'first-generation' devices, which have been the principle devices tested in stroke trials.Our aims were to determine the rates of successful recanalization and functional independence in acute stroke patients treated with stent retrievers. We also sought to assess the safety outcomes of stent retrievers by assessing the rates of mortality and intra-cranial haemorrhage.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis of studies which utilized stent retrievers as sole treatment or as part of a multi-modal approach in acute ischaemic stroke.

RESULTS

We identified 20 eligible studies: 17 on Solitaire (ev3/Covidien, Irvine, California, USA) (n = 762) and three on Trevo (Stryker, Kalamazoo, Michigan, USA) (n = 210). The mean age of participants was 66.8 (range 62.1-73.0) years and the M:F ratio was 1.1:1. The average stroke severity score (National Institutes of Health Stroke Scale (NIHSS)) at presentation was 17.2. The weighted mean symptom onset to arterial puncture and procedural duration were 265.4 minutes and 54.8 minutes, respectively.Successful recanalization was achieved in 84.5% of patients with a weighted mean of 2.0 stent retriever passes. Independent functional outcome was achieved in 51.2% and the mortality rate was 16.8%.

CONCLUSION

Stent retrievers have the potential to achieve a high rate of recanalization and functional independence whilst being relatively safe. They should be assessed in well-designed randomized controlled trials to determine their efficacy and assess whether they compare favourably with 'standard treatment' in stroke.

Lessons learnt from recent endovascular stroke trials: finding a way to move forward

The advent of stentrievers provided momentum for endovascular stroke therapy. Hopes were dampened after three randomized trials showed no clear benefit of endovascular therapy. This review discusses the results of these trials results and shortcomings. A detailed discussion will follow on the design, conduct and analysis of current and future endovascular stroke trials. Steps to improve the workflow of acute stroke cases from the time they enter the emergency department until endovascular reperfusion is achieved can significantly shorten the time from onset to successful reperfusion. These factors in addition to using novel approaches to analyze data and minimize delays caused by the consent process are perceived to be sufficient to demonstrate the efficacy of endovascular stroke therapy.

Future directions for intra-arterial therapy for acute ischaemic stroke: is there life after three negative randomized controlled studies?

Background: The three randomised controlled trials, Interventional Management of Stroke III (IMS3), Mechanical Retrieval and Revascularization of Stroke Clots Using Embolectomy (MR RESCUE) and Synthesis Expanasion: A Randomized Controlled Trial on Intra-Arterial Versus Intravenous Thrombolysis in Acute Ischaemic Stroke (SYNTHESIS EXP) showed no significant difference in clinical outcomes comparing intra-arterial (IA) therapy with intravenous thrombolysis. This article will explore the reasons for failure to show superiority of IA therapy. Summary: There are many reasons for the disappointing results of the three randomised controlled trials. Opposing views on IA therapy exist. Critics argue that only a small percentage of patients will be eligible for IA therapy and that it will never be cost-effective. Additionally, current trials have failed to address superior recanalization rates of new generation devices and lack of patient selection by advanced imaging. Time-to-treatment is longer in these randomised controlled trials and stroke outcomes were worse than anticipated. The current randomised controlled trials also took long periods to complete. There is emerging evidence that general anesthetic negatively influences outcome. Next generation trials will attempt to address these issues. Key Messages: There are disparate explanations for the disappointing results from the three IA therapy randomized controlled studies. Poor recanalisation rates with first generation endovascular devices, lack of advanced neuroimaging to aid in patient selection, lack of data surrounding the use of general anaesthesia, and prolonged time-to-treatment are potential contributors to negative results. The new generation of trials has the potential of addressing these pressing issues.

Endovascular stroke therapy

BACKGROUND

Following the development of intravenous thrombolysis as a successful treatment for ischaemic stroke, advances in neurointerventional radiology have facilitated endovascular approaches to treatment. This article reviews the available endovascular therapeutic options and their evidence-base.

SUMMARY

Initial studies demonstrated that endovascular treatment of ischaemic stroke with intra-arterial thrombolysis and/or the use of clot-retrieval, thrombus aspiration and stent-retriever devices produced early recanalisation and reperfusion and improved neurological outcome. More recent randomised trials, however, have failed to show translation of recanalisation into successful clinical outcome with 'time to treatment' proving crucial. In this rapidly evolving field, combined therapy incorporating intravenous and intra-arterial thrombolysis in combination with endovascular clot-retrieval has been developed and further studies are expected to yield better evidence to guide the optimal treatment of acute cerebral ischaemia.

Impact of age and baseline NIHSS scores on clinical outcomes in the mechanical thrombectomy using solitaire FR in acute ischemic stroke study

BACKGROUND AND PURPOSE

Age and stroke severity are inversely correlated with the odds of favorable outcome after ischemic stroke. A previously proposed score for Stroke Prognostication Using Age and NIHSS Stroke Scale (SPAN) indicated that SPAN-100-positive patients (ie, age + NIHSS score = 100 or more) do not benefit from IV-tPA. If this finding holds true for endovascular therapy, this score can impact patient selection for such interventions. This study investigated whether a score combining age and NIHSS score can improve patients' selection for endovascular stroke therapy.

MATERIALS AND METHODS

The SPAN index was calculated for patients in the prospective Solitaire FR Thrombectomy for Acute Revascularization study: an international single-arm multicenter cohort for anterior circulation stroke treatment by using the Solitaire FR. The proportion with favorable outcome (90-day mRS score ≤2) was compared between SPAN-100-positive versus-negative patients.

RESULTS

Of the 202 patients enrolled, 196 had baseline NIHSS scores. Fifteen (7.7%) patients were SPAN-100-positive. There was no difference in the rate of successful reperfusion (Thrombolysis In Cerebral Infarction 2b or 3) between SPAN-100-positive versus -negative groups (93.3% versus 82.8%, respectively; P = .3). Stroke SPAN-100-positive patients had a significantly lower proportion of favorable clinical outcomes (26.7% versus 60.8% in SPAN-100-negative, P = .01). In a multivariable analysis, SPAN-100-positive status was associated with lower odds of favorable outcome (OR, 0.3; 95% CI, 0.1-0.9; P = .04). A higher baseline Alberta Stroke Program Early CT Score and a short onset to revascularization time also predicted favorable outcome in the multivariable analysis.

CONCLUSIONS

A significantly lower proportion of patients with a positive SPAN-100 achieved favorable outcome in this cohort. SPAN-100 was an independent predictor of favorable outcome after adjusting for time to treatment and the extent of preintervention tissue damage according to the Alberta Stroke Program Early CT Score.

Early experience with stent retrievers and comparison with previous-generation mechanical thrombectomy devices for acute ischemic stroke

Object

There is limited information regarding patient outcomes following interventions for stroke during the window for endovascular therapy. Studies have suggested that recently approved stent retrievers are safer and more effective than earlier-generation thrombectomy devices. The authors compared cases in which the Solitaire-FR device was used to those in which a MERCI or Penumbra device was used.

Methods

This study is a single-center retrospective review of 102 consecutive cases of acute stroke in which patients were treated with mechanical thrombectomy devices between 2007 and 2013. Multivariate models, adjusted for confounding factors, were used to investigate functional independence (modified Rankin Scale [mRS] score ≤ 2, and successful reperfusion (thrombolysis in cerebral infarction [TICI] score ≥ 2b).

Results

Thrombectomy device had a significant impact on functional independence (mRS score ≤ 2) at discharge from the hospital (p = 0.040). Solitaire-FR treatment resulted in significantly more patients being discharged as functionally independent in comparison with MERCI treatment (p = 0.016). A multivariate model found the use of Solitaire-FR to improve the odds of good clinical outcome in comparison with prior-generation devices (OR 6.283, 95% CI 1.785–22.119, p = 0.004). Additionally, the use of Solitaire-FR significantly increased the odds of successful reperfusion (OR 3.247, 95% CI 1.160–9.090, p = 0.025).

Conclusions

The stent retriever Solitaire-FR significantly improved the odds of functional independence and successful revascularization of the arterial tree. New interventional technology for stroke continues to mature, but randomized trials are needed to establish the actual benefit to specific patient populations.

Treatment of acute cerebral artery occlusion using the Penumbra system: our early experience

Intravenous recombinant tissue-type plasminogen activator (rt-PA) therapy is highly recommended to patients who are diagnosed with ischemic stroke within 4.5 hours after the onset while mechanical clot retrieval can be attempted in patients who are not indicated for or cannot effectively receive intravenous rt-PA therapy. In this article, we report early treatment outcomes and discuss the usefulness of mechanical clot retrieval using the Penumbra system (Penumbra Inc., Alameda, California, USA), especially in terms of technical cautions during the procedure and adaptability to elderly and high National Institutes of Health Stroke Scale (NIHSS) patients. We included 7 patients with thromboembolic occlusion. Pre-treatment NIHSS score ranged from 11 to 36 (mean: 24.9). All patients achieved good recanalization [thrombolysis in cerebral infarction (TICI) grade 2a or greater] without complications. The NIHSS score at 30 days after the treatment ranged between 0 and 28 (mean: 12.4), and improved more than 10 points in 4 of the 7 patients (57.1%). To obtain good recanalization without complications, selection of suitable reperfusion catheter and careful manipulation of separator prefiguring the occluded distal vessels are essential. The improved NIHSS score at 30 days after the treatment may have led to favorable results, such as an increased participation in available rehabilitation programs and the alleviation of the burden of care. Our findings suggest that the Penumbra system might be effective for treatment in elderly patients or patients with high NIHSS score wherein rt-PA therapy is inadvisable or ineffective in ischemic stroke secondary to large vessel occlusion. Recanalization can improve their quality of life on condition that the procedure is performed successfully without serious complications.

Inter- and intraobserver agreement in scoring angiographic results of intra-arterial stroke therapy

BACKGROUND AND PURPOSE

Angiographic results are commonly used as surrogate markers of the success of intra-arterial therapies for acute stroke. Inter- and intraobserver agreement in judging angiographic results remain poorly characterized. Our goal was to assess 2 commonly used revascularization scales.

MATERIALS AND METHODS

A portfolio of 148 pre- and post treatment images of 37 cases of proximal anterior circulation occlusions was electronically sent to 12 expert observers who were asked to grade treatment outcomes according to recanalization (of arterial occlusive lesion) or reperfusion (TICI) scales. Three expert observers had to score treatment outcomes by using a similar portfolio of 32 patients or when they had full access to all angiographic data, twice for each method 3-12 months apart. Results were analyzed by using κ statistics.

RESULTS

Agreement among 9 responding observers was moderate for both the TICI (κ = 0.45 ± 0.01) and arterial occlusive lesion (κ = 0.39 ± 0.16) scales. Agreement was similar (moderate) when 3 observers had access to a portfolio (κ = 0.59 ± 0.06 and 0.49 ± 0.07, respectively) or to the full angiographic data (κ = 0.54 ± 0.06 and 0.59 ± 0.07, respectively). Intraobserver agreement was "fair to moderate" for both methods. Interobserver agreement became "substantial" (>0.6) when outcomes were dichotomized into "success" (TICI 2b, 3; arterial occlusive lesion II, III or "failure"; the results were judged more favorably when the arterial occlusive lesion rather than the TICI scale was used.

CONCLUSIONS

There is an important variability in the assessment of angiographic outcomes of endovascular treatments, invalidating comparisons among publications. A simple dichotomous judgment can be used as a surrogate outcome when treatments are assessed by the same observers in randomized trials.

Evaluation of interval times from onset to reperfusion in patients undergoing endovascular therapy in the Interventional Management of Stroke III trial

BACKGROUND

Meaningful delays occurred in the Interventional Management of Stroke (IMS) III trial. Analysis of the work flow will identify factors contributing to the in-hospital delays.

METHODS AND RESULTS

In the endovascular arm of the IMS III trial, the following time intervals were calculated: stroke onset to emergency department arrival; emergency department to computed tomography (CT); CT to intravenous tissue plasminogen activator start; intravenous tissue plasminogen activator start to randomization; randomization to groin puncture; groin puncture to thrombus identification; thrombus identification to start of endovascular therapy; and start of endovascular therapy to reperfusion. The effects of enrollment time, CT angiography use, interhospital transfers, and intubation on work flow were evaluated. Delays occurred notably in the time intervals from intravenous tissue plasminogen activator initiation to groin puncture (median 84 minutes) and start of endovascular therapy to reperfusion (median 85 minutes). The CT to groin puncture time was significantly shorter during working hours than after. Times from emergency department to reperfusion and groin puncture to reperfusion decreased over the trial period. Patients with CT angiography had shorter emergency department to reperfusion and onset to reperfusion times. Transfer of patients resulted in a longer onset to reperfusion time compared with those treated in the same center. Age, sex, National Institutes of Health Stroke Scale score, and intubation did not affect delays.

CONCLUSIONS

Important delays were identified before reperfusion in the IMS III trial. Delays decreased as the trial progressed. Use of CT angiography and endovascular treatment in the same center were associated with time savings. These data may help in optimizing work flow in current and future endovascular trials.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00359424.

Reperfusion therapy of acute ischaemic stroke and acute myocardial infarction: similarities and differences

The evolution of reperfusion therapy in acute myocardial infarction and acute ischaemic stroke has many similarities: thrombolysis is superior to placebo, intra-arterial thrombolysis is not superior to intravenous (i.v.), facilitated intervention is of questionable value, and direct mechanical recanalization without thrombolysis is proven (myocardial infarction) or promising (stroke) to be superior to thrombolysis-but only when started with no or minimal delay. However, there are also substantial differences. Direct catheter-based thrombectomy in acute ischaemic stroke is more difficult than primary angioplasty (in ST-elevation myocardial infarction [STEMI]) in many ways: complex pre-intervention diagnostic workup, shorter time window for clinically effective reperfusion, need for an emergent multidisciplinary approach from the first medical contact, vessel tortuosity, vessel fragility, no evidence available about dosage and combination of peri-procedural antithrombotic drugs, risk of intracranial bleeding, unclear respective roles of thrombolysis and mechanical intervention, lower number of suitable patients, and thus longer learning curves of the staff. Thus, starting acute stroke interventional programme requires a lot of learning, discipline, and humility. Randomized trials comparing different reperfusion strategies provided similar results in acute ischaemic stroke as in STEMI. Thus, it might be expected that also a future randomized trial comparing direct (primary) catheter-based thrombectomy vs. i.v. thrombolysis could show superiority of the mechanical intervention if it would be initiated without delay. Such randomized trial is needed to define the role of mechanical intervention alone in acute stroke treatment.