Thrombectomy within 8 hours after symptom onset in ischemic stroke

A systematic review and meta-analysis of randomized controlled trials of endovascular thrombectomy compared with best medical treatment for acute ischemic stroke

BACKGROUND

Acute ischemic strokes involving occlusion of large vessels usually recanalize poorly following treatment with intravenous thrombolysis. Recent studies have shown higher recanalization and higher good outcome rates with endovascular therapy compared with best medical management alone. A systematic review and meta-analysis investigating the benefits of all randomized controlled trials of endovascular thrombectomy where at least 25% of patients were treated with a thrombectomy device for the treatment of acute ischemic stroke compared with best medical treatment have yet to be performed.

AIM

To perform a systematic review and a meta-analysis evaluating the effectiveness of endovascular thrombectomy compared with best medical care for treatment of acute ischemic stroke.

SUMMARY OF REVIEW

Our search identified 437 publications, from which eight studies (totaling 2423 patients) matched the inclusion criteria. Overall, endovascular thrombectomy was associated with improved functional outcomes (modified Rankin Scale 0-2) [odds ratio 1·56 (1·32-1·85), P < 0·00001]. There was a tendency toward decreased mortality [odds ratio 0·84 (0·67-1·05), P = 0·12], and symptomatic intracerebral hemorrhage was not increased [odds ratio 1·03 (0·71-1·49), P = 0·88] compared with best medical management alone. The odds ratio for a favorable functional outcome increased to 2·23 (1·77-2·81, P < 0·00001) when newer generation thrombectomy devices were used in greater than 50% of the cases in each trial.

CONCLUSIONS

There is clear evidence for improvement in functional independence with endovascular thrombectomy compared with standard medical care, suggesting that endovascular thrombectomy should be considered the standard effective treatment alongside thombolysis in eligible patients.

Time-Resolved C-Arm Computed Tomographic Angiography Derived From Computed Tomographic Perfusion Acquisition

Background and Purpose—

Multimodal imaging using cone beam C-arm computed tomography (CT) may shorten the delay from ictus to revascularization for acute ischemic stroke patients with a large vessel occlusion. Largely because of limited temporal resolution, reconstruction of time-resolved CT angiography (CTA) from these systems has not yielded satisfactory results. We evaluated the image quality and diagnostic value of time-resolved C-arm CTA reconstructed using novel image processing algorithms.

Methods—

Studies were done under an Institutional Review Board approved protocol. Postprocessing of data from 21 C-arm CT dynamic perfusion acquisitions from 17 patients with acute ischemic stroke were done to derive time-resolved C-arm CTA images. Two observers independently evaluated image quality and diagnostic content for each case. ICC and receiver-operating characteristic analysis were performed to evaluate interobserver agreement and diagnostic value of this novel imaging modality.

Results—

Time-resolved C-arm CTA images were successfully generated from 20 data sets (95.2%, 20/21). Two observers agreed well that the image quality for large cerebral arteries was good but was more limited for small cerebral arteries (distal to M1, A1, and P1). receiver-operating characteristic curves demonstrated excellent diagnostic value for detecting large vessel occlusions (area under the curve=0.987–1).

Conclusions—

Time-resolved CTAs derived from C-arm CT perfusion acquisitions provide high quality images that allowed accurate diagnosis of large vessel occlusions. Although image quality of smaller arteries in this study was not optimal ongoing modifications of the postprocessing algorithm will likely remove this limitation. Adding time-resolved C-arm CTAs to the capabilities of the angiography suite further enhances its suitability as a one-stop shop for care for patients with acute ischemic stroke.

Impact of Collateral Status Evaluated by Dynamic Computed Tomographic Angiography on Clinical Outcome in Patients With Ischemic Stroke

Background and Purpose—

Status of collateral circulation is a strong predictor of outcome after acute ischemic stroke. Our aim was to compare the predictive value of strategies for collateral blood flow assessment with dynamic computed tomographic angiography (CTA) and conventional single-phase CT angiography.

Methods—

Patients with a proximal middle cerebral artery occlusion underwent noncontrast CT, single-phase CTA and whole brain CT perfusion/dynamic CTA within 9 hours after stroke onset. We defined poor outcome as a score on the modified Rankin Scale score of ≥3. The association between collateral score and clinical outcome at 3 months was analyzed with Poisson regression. The prognostic value of collateral scoring with dynamic CTA and single-phase CTA in addition to age, stroke severity, and noncontrast CT was assessed with logistic regression and summarized with the area under the curve.

Results—

Seventy patients were included, with a mean age of 68 years. We observed an increased risk of poor outcome in patients with poor collaterals on single-phase CTA (risk ratio, 1.8; 95% confidence interval, 1.0–3.1) and on dynamic CTA (risk ratio, 2.0; 95% confidence interval, 1.5–2.7). The prediction of poor clinical outcome by means of collateral adjustment was better with dynamic CTA (area under the curve, 0.84; likelihood ratio test P <0.01) than by single-phase CTA (area under the curve, 0.80; likelihood ratio test P =0.33).

Conclusions—

Collateral assessment with dynamic CTA better predicts clinical outcome at 3 months than single-phase conventional CTA.

Clinical Trial Registration—

URL: http://www.trialregister.nl/trialreg . Unique identifier: NTR1804. URL: http://www.clinicaltrials.gov . Unique identifier: NCT00880113.

Phone and Video-Based Modalities of Central Blinded Adjudication of Modified Rankin Scores in an Endovascular Stroke Trial

Background and Purpose—

The standard outcome measure in stroke research is modified Rankin scale (mRS) evaluated by local blinded investigators. We aimed to assess feasibility and reliability of 2 central adjudication methods of mRS in the setting of a randomized endovascular stroke trial.

Methods—

This is a secondary analysis derived from the Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset (REVASCAT) trial cohort. Primary outcome was distribution of mRS at 90 days. Local evaluation was done by certified investigators masked to treatment assignment using structured face-to-face interviews. In addition, central assessment was performed by 2 independent raters via structured phone interview (n=120) and via video recordings of the face-to-face interviews with local investigators (n=106). Interrater agreement was evaluated using kappa and discordance statistics. Sensitivity analyses for the primary end point using different adjudication approaches were performed. Correlation between mRS obtained with each modality and 24-hour follow-up infarct volumes was studied.

Results—

Using local evaluation as the reference, higher agreement rates were noted with central video than with central phone evaluations ( k w 0.92 [0.88–0.96] versus 0.77 [0.72–0.83]). Discrepancies in mRS scoring between local and central raters (phone- and video-based) were similar in both treatment allocation arms. Sensitivity analyses showed benefit of endovascular treatment irrespective of adjudication method, but higher odds ratios were observed with local evaluations. Final infarct volume was similarly correlated with mRS across all 3 evaluation modalities.

Conclusions—

Central adjudication of mRS is feasible, reducing interrater variability and avoiding potential problems related to lack of blinding. Our findings may have implications in the planning of future randomized acute stroke trials, especially in those including nonpharmacological interventions.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01692379.

Mechanical Thrombectomy in and Outside the REVASCAT Trial: Insights From a Concurrent Population-Based Stroke Registry

BACKGROUND AND PURPOSE

Recent trials have shown the superiority of endovascular thrombectomy (EVT) over medical therapy alone in certain stroke patients with proximal arterial occlusion. Using data from the Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke due to Anterior Circulation Large Vessel Occlusion Presenting Within 8-Hours of Symptom Onset (REVASCAT) and a parallel reperfusion treatment registry, we sought to assess the utilization of EVT in a defined patient population, comparing the outcomes of patients treated in and outside the REVASCAT trial.

METHODS

SONIIA [Sistema Online d'Informació de l'Ictus Agut], a population-based, government-mandated, prospective registry of reperfusion therapies for stroke encompassing the entire population of Catalonia, was used as data source. The registry documents 5 key inclusion criteria of the REVASCAT trial: age, stroke severity, time to treatment, baseline functional status, and occlusion site. We compared procedural, safety, and functional outcomes in patients treated inside and outside the trial.

RESULTS

From November 2012 to December 2014, out of 17596 ischemic stroke patients in Catalonia (population 7.5 million), 2576 patients received reperfusion therapies (17/100000 inhabitants-year), mainly intravenous thrombolysis only (2036). From the remaining 540 treated with EVT, 103 patients (out of 206 randomized) were treated within REVASCAT and 437 outside the trial. Of these, 399 did not fulfill some of the study criteria, and 38 were trial candidates (8 treated at REVASCAT centers and 30 at 2 non-REVASCAT centers). The majority of procedural, safety, and functional outcomes were similar in patients treated with EVT within and outside REVASCAT.

CONCLUSIONS

REVASCAT enrolled nearly all eligible patients representing one third of all patients treated with EVT. Patients treated with EVT within and outside REVASCAT had similar outcomes, reinforcing the therapeutic value of EVT.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01692379.

Endovascular Therapy Is Effective and Safe for Patients With Severe Ischemic Stroke: Pooled Analysis of Interventional Management of Stroke III and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands Data

BACKGROUND AND PURPOSE

We assessed the effect of endovascular treatment in acute ischemic stroke patients with severe neurological deficit (National Institutes of Health Stroke Scale score, ≥20) after a prespecified analysis plan.

METHODS

The pooled analysis of the Interventional Management of Stroke III (IMS III) and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands (MR CLEAN) trials included participants with an National Institutes of Health Stroke Scale score of ≥20 before intravenous tissue-type plasminogen activator (tPA) treatment (IMS III) or randomization (MR CLEAN) who were treated with intravenous tPA ≤3 hours of stroke onset. Our hypothesis was that participants with severe stroke randomized to endovascular therapy after intravenous tPA would have improved 90-day outcome (distribution of modified Rankin Scale scores), when compared with those who received intravenous tPA alone.

RESULTS

Among 342 participants in the pooled analysis (194 from IMS III and 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared with the intravenous tPA group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.66). In the logistic regression model of the dichotomous outcome (modified Rankin Scale score, 0-2, or functional independence), the endovascular group had superior outcomes (adjusted odds ratio, 1.97; 95% confidence interval, 1.09-3.56). Functional independence (modified Rankin Scale score, ≤2) at 90 days was 25% in the endovascular group when compared with 14% in the intravenous tPA group.

CONCLUSIONS

Endovascular therapy after intravenous tPA within 3 hours of symptom onset improves functional outcome at 90 days after severe ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424 (IMS III) and ISRCTN10888758 (MR CLEAN).

Endovascular Treatment for Acute Ischemic Stroke: Updates and Future Implications

Stroke constitutes the primary cause of acquired disability in adults and is a second leading cause of death worldwide. The low recanalization rate after intravenous thrombolysis calls for an alternate therapy for acute ischemic stroke. The methodology for endovascular treatment has evolved greatly over the past two decades. The past 6 months have seen great progress in this area, with several randomized clinical trials all proving the efficacy and safety of endovascular treatment. Three key factors are important for good functional outcome after endovascular treatment: fast imaging to prove proximal occlusion and to exclude large infarct core, using mainly the stent retriever thrombectomy devices and establishing an efficient workflow to achieve fast reperfusion. Although positive results of RCTs are encouraging and bring what is urgently needed in the field, transforming these positive results into clinical practice will be both a challenge and opportunity of the next 5 years. It will need hard work, leadership and cooperation of all members involved in the chain of treating a stroke patient. In the wake of these positive trials, hospitals and professional organizations are working together to save every minute when fighting against this devastating disease.

Outcome and periprocedural time management in referred versus directly admitted stroke patients treated with thrombectomy

BACKGROUND

After thrombectomy has shown to be effective in acute stroke patients with large vessel occlusion, the potential benefit of secondary referral for such an intervention needs to be validated.

AIMS

We aimed to compare consecutive stoke patients directly admitted and treated with thrombectomy at a neurointerventional centre with patients secondarily referred for such a procedure from hospitals with a stroke unit.

METHODS

Periprocedure times and mortality in 300 patients primarily treated in eight neurointerventional centres were compared with 343 patients referred from nine other hospitals in a prospective multicentre study of a German neurovascular network. Data on functional outcome at 3 months was available in 430 (76.4%) patients.

RESULTS

In-hospital mortality (14.8% versus 11.7%, p = 0.26) and 3 months mortality (21.9% versus 24.1%, p = 0.53) were not statistically different in both patient groups despite a significant shorter symptom to groin puncture time in directly admitted patients, which was mainly caused by a longer interfacility transfer time. We found a nonsignificant trend for better functional outcome at 3 months in directly admitted patients (modified Rankin Scale 0-2, 44.0% versus 35.7%, p = 0.08).

CONCLUSIONS

Our results show that a drip-and-ship thrombectomy concept can be effectively organized in a metropolitan stroke network. Every effort should be made to speed up the emergency interfacility transfer to a neurointerventional centre in stroke patients eligible for thrombectomy after initial brain imaging.

Endovascular thrombectomy for the treatment of acute ischemic stroke

ABSTRACT Few patients benefit from the current standard treatment for acute ischemic stroke (AIS), encouraging the development of new treatments. Objective To systematically review the literature on the efficacy and/or safety of endovascular thrombectomy in AIS compared to standard treatment and to identify ongoing randomized controlled trials (RCTs). Method Searches for RCTs were performed in Medline/Embase, and for ongoing trials: International Clinical Trial Registry Platform, Clinicaltrials.gov and ISRCTN registry (to June 15th, 2015). Results From the eight published RCTs, five showed the superiority of treatment that includes thrombectomy compared to standard care alone. From the 13 ongoing RCTs, 3 have been halted, one has not started, one has unknown status and eight will end between 2016 - 2020. Conclusion Evidence favours a combination of the standard therapy with endovascular thrombectomy. The selection criteria however limit the number of people who can benefit. Further studies are needed to prove its cost-effectiveness.

Brain Imaging Using Mobile CT: Current Status and Future Prospects

Computed tomography (CT) is an invaluable tool in the diagnosis of many clinical conditions. Several advancements in biomedical engineering have achieved increase in speed, improvements in low-contrast detectability and image quality, and lower radiation. Portable or mobile CT constituted one such important advancement. It is especially useful in evaluating critically ill, intensive care unit patients by scanning them at bedside. A paradigm shift in utilization of mobile CT was its installation in ambulances for the management of acute stroke. Given the time sensitive nature of acute ischemic stroke, Mobile stroke units (MSU) were developed in Germany consisting of an ambulance equipped with a CT scanner, point of care laboratory system, along with teleradiological support. In a radical reconfiguration of stroke care, the MSU would bring the CT scanner to the stroke patient, without waiting for the patient at the emergency room. Two separate MSU projects in Saarland and Berlin demonstrated the safety and feasibility of this concept for prehospital stroke care, showing increased rate of intravenous thrombolysis and significant reduction in time to treatment compared to conventional care. MSU also improved the triage of patients to appropriate and specialized hospitals. Although multiple issues remain yet unanswered with the MSU concept including clinical outcome and cost-effectiveness, the MSU venture is visionary and enables delivery of life-saving and enhancing treatment for ischemic and hemorrhagic stroke. In this review, we discuss the development of mobile CT and its applications, with specific focus on its use in MSUs along with our institution's MSU experience.

Inadvertent Stent Retriever Detachment: A Multicenter Case Series and Review of Device Experience FDA Reports

Mechanical thrombectomy using retrievable stents or stent retriever devices has become the mainstay of intra-arterial therapy for acute ischemic stroke. The recent publication of a series of positive trials supporting intra-arterial therapy as standard of care for the treatment of large vessel occlusion will likely further increase stent retriever use. Rarely, premature stent detachment during thrombectomy may be encountered. In our multicenter case series, we found a rate of detachment of less than 1% (n = 7/1,067), and all were first-generation Solitaire FR devices. A review of the US Food and Drug Administration database of device experience yielded 90 individual adverse reports of detachment. There were 82, 1 and 7 detachments of Solitaire FR (first generation), Solitaire FR2 (second generation) and Trevo devices, respectively. We conclude with a brief overview of the technical and procedural considerations which may be helpful in avoiding this rare complication.

Impact of Collateral Status on Successful Revascularization in Endovascular Treatment: A Systematic Review and Meta-Analysis

BACKGROUND

Pre-treatment collateral status may be associated with the rates of successful revascularization in acute ischemic stroke patients receiving endovascular treatment (EVT). We conducted a systematic review and meta-analysis to synthesize relevant evidence currently available.

METHODS

Relevant full-text articles published in English since January 1, 2000, reporting associations between collateral status and successful reperfusion and/or recanalization in acute ischemic stroke patients receiving EVT in cohort or case-control studies, or randomized clinical trials, were retrieved through search of PubMed. Study selection, data extraction and study quality assessment were carried out by 2 investigators. Risk ratios (RR) were pooled for good vs. poor collaterals for the outcomes of successful reperfusion and recanalization, based on random-effects models. Subgroup analyses were conducted to explore for potential factors that might interfere with the effects of pre-treatment collateral status on reperfusion by EVT.

RESULTS

In total, 27 studies (2,366 subjects) were included in qualitative analysis, among which 24 studies (2,239 subjects) were quantitatively analyzed. Overall, good pre-treatment collaterals significantly increased the rate of both successful reperfusion (RR 1.28, 95% CI 1.17-1.40; p < 0.001) and recanalization (RR 1.23, 95% CI 1.06-1.42; p = 0.006), as compared with poor collaterals. Subgroup analyses revealed that the effects of collateral status on successful reperfusion by EVT might be different between populations with different ethnicities.

CONCLUSIONS

Good pre-treatment collaterals may enhance the rates of successful reperfusion and recanalization in EVT for acute ischemic stroke. This may partly explain the favorable effects of good pre-treatment collaterals on clinical outcomes of stroke patients receiving EVT. Thus, it would be valuable to assess the collateral status prior to EVT in acute ischemic stroke. But studies are needed to further verify if the positive effects of good collaterals on revascularization by EVT are restricted to certain subgroups of patients.

Emergent mechanical thrombectomy for acute stroke using the Mindframe Capture LP system: initial single-center experience

Background

Mechanical thrombectomy using stentrievers is the standard of care for emergent large vessel occlusion stroke. Data on the use of stentrievers in smaller caliber vessels are sparse.

Objective

To present our initial experience with the Mindframe Capture LP device, which was designed for mechanical thrombectomy in small cerebral arteries.

Methods

A retrospective chart review was conducted of patients who underwent Mindframe device assisted emergent thrombectomy. Clinical, imaging, procedural and early follow-up data were obtained.

Results

Nine patients met inclusion criteria (5 men, median age 62 years). Median National Institute of Health Stroke Scale (NIHSS) score was 18 (IQR 9–22), and 6 patients received intravenous tissue plasminogen activator. Six patients had M2 segment occlusions, and 2 patients had distal M1 segment occlusions of the middle cerebral artery. One had distal basilar artery occlusion. Median vessel diameter at the thrombus was 1.7 mm (IQR 1.5–2.5). In all 9 patients the Mindframe device was used together with manual aspiration, with median groin puncture to recanalization time of 35 min (IQR 27–54), and median procedural time of 67 min (IQR 51–91). Final Thrombolysis in Cerebral Infarction score was 3 and 2b in 4 patients each (89% total), and 2a in 1 patient. No patient had any postprocedural complications or symptomatic intracerebral hemorrhage. Median postprocedure and discharge NIHSS were 4 and 1, respectively.

Conclusions

Our data suggest that the Mindframe device is safe and effective for rapid treatment of acute strokes involving small caliber intracranial vessels. Further study in a larger cohort is warranted.

Mechanical Thrombectomy for Isolated M2 Occlusions: A Post Hoc Analysis of the STAR, SWIFT, and SWIFT PRIME Studies

BACKGROUND AND PURPOSE

Mechanical thrombectomy is beneficial for patients with acute ischemic stroke and a proximal anterior occlusion, but it is unclear if these results can be extrapolated to patients with an M2 occlusion. The purpose of this study was to examine the technical aspects, safety, and outcomes of mechanical thrombectomy with a stent retriever in patients with an isolated M2 occlusion who were included in 3 large multicenter prospective studies.

MATERIALS AND METHODS

We included patients from the Solitaire Flow Restoration Thrombectomy for Acute Revascularization (STAR), Solitaire With the Intention For Thrombectomy (SWIFT), and Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME) studies, 3 large multicenter prospective studies on thrombectomy for ischemic stroke. We compared outcomes and technical details of patients with an M2 with those with an M1 occlusion. All patients were treated with a stent retriever. Imaging data and outcomes were scored by an independent core laboratory. Successful reperfusion was defined as modified Thrombolysis in Cerebral Infarction score of 2b/3.

RESULTS

We included 50 patients with an M2 and 249 patients with an M1 occlusion. Patients with an M2 occlusion were older (mean age, 71 versus 67 years; P = .04) and had a lower NIHSS score (median, 13 versus 17; P < .001) compared with those with an M1 occlusion. Procedural time was nonsignificantly shorter in patients with an M2 occlusion (median, 29 versus 35 minutes; P = .41). The average number of passes with a stent retriever was also nonsignificantly lower in patients with an M2 occlusion (mean, 1.4 versus 1.7; P = .07). There were no significant differences in successful reperfusion (85% versus 82%, P = .82), symptomatic intracerebral hemorrhages (2% versus 2%, P = 1.0), device-related serious adverse events (6% versus 4%, P = .46), or modified Rankin Scale score 0-2 at follow-up (60% versus 56%, P = .64).

CONCLUSIONS

Endovascular reperfusion therapy appears to be feasible in selected patients with ischemic stroke and an M2 occlusion.

The emerging age of endovascular treatment of acute ischaemic stroke and the role of CT angiography in patient work-up: a guide for the radiologist

Recent trial evidence suggests that for patients suffering large-vessel occlusive stroke, endovascular therapy based on the stent-retriever technique is associated with superior clinical outcomes when compared to intravenous thrombolysis alone. The challenge now is how this service is to be delivered. This may involve both centralisation of services around large cities and development of robust networks to receive patients from district general hospitals situated further afield. Both diagnostic and interventional neuroradiology will need to expand. Furthermore, we suggest that it would be advantageous for radiology departments in those hospitals receiving hyperacute stroke patients to perform computed tomography (CT) angiography in addition to non-contrast CT, which also has implications for service delivery in these units. This could swiftly aid identification of patients who might benefit from thrombectomy and improve decision-making through demonstration of occlusive thrombus and of collateral status.

Development and Assessment of a Computer Algorithm for Stroke Vascular Localization Using Components of the National Institutes of Health Stroke Scale

BACKGROUND

The National Institutes of Health Stroke Scale (NIHSS) was not intended to be used to determine the stroke's vascular distribution. The aim of this study was to develop, assess the reliability, and validate a computer algorithm based on the NIHSS for this purpose.

METHODS

Two cohorts of patients with ischemic stroke having similar distributions of Oxfordshire localizations (total anterior, partial anterior, lacunar, and posterior circulation) based on neuroimaging were identified. The first cohort (n = 40) was used to develop a computer algorithm for vascular localization using a modified version of the NIHSS (NIHSS-Localization [NIHSS-Loc]) that included the laterality of selected deficits; the second (n = 20) was used to assess the reliability of algorithm-based localizations compared to those of 2 vascular neurologists. The validity of the algorithm-based localizations was assessed in comparison to neuroimaging. Agreement was assessed using the unweighted kappa (κ) statistic.

RESULTS

Agreement between the 2 raters using the standard NIHSS was slight to moderate (κ = .36, 95% confidence interval [CI] .10-.61). Inter-rater agreement significantly improved to the substantial to almost perfect range using the NIHSS-Loc (κ = .88, 95% CI .73-1.00). Agreement was perfect when the 2 raters entered the data into the NIHSS-Loc computer algorithm (κ = 1.00, 95% CI 1.00-1.00). Agreement between the algorithm localization and neuroimaging results was fair to moderate (κ = .59, 95% CI .35-.84) and not significantly different from the localizations of either rater using the NIHSS-Loc.

CONCLUSION

A computerized, modified version of the standard NIHSS can be used to reliably and validly assign the vascular distribution of an acute ischemic stroke.

Distance to Thrombus in Acute Middle Cerebral Artery Occlusion Predicts Target Mismatch and Ischemic Penumbra

BACKGROUND AND PURPOSE

In patients with occlusion of the middle cerebral artery (MCA) treated by intravenous thrombolysis (IVT), the distance to thrombus (DT) has been proposed as a predictor of outcome. The purpose of the present study was to investigate how DT relates to dynamic susceptibility contrast perfusion metrics.

METHODS

Retrospective analysis was undertaken of patients who were diagnosed with acute MCA occlusion by magnetic resonance imaging and treated with IVT. Volumes of time-to-maximum (Tmax) perfusion deficits and diffusion-weighted imaging (DWI) lesions, diffusion-perfusion mismatch volumes, and the presence of target mismatch were determined. Correlations between the above stoke measures and DT were then calculated.

RESULTS

Fifty-five patients were included. DT showed significant inverse correlations with Tmax greater than 4, 6, 8, and 10 seconds, respectively, and mismatch volumes. Using the DT group median (14 mm) as a separator, significant intergroup differences were observed for Tmax greater than 4, 6, and 8 seconds, respectively, and for mismatch volumes. Grouping DT into quartiles showed significant intergroup differences regarding mismatch volumes and Tmax values greater than 4 and 6 seconds. Binary logistic regression identified DT (odds ratio [OR] = .89; 95% confidence interval [CI], .81-.99) and DWI lesion volumes (OR = .92; 95% CI, .86-.97) as independent predictors of target mismatch. A low DT predicted target mismatch with an area under the curve of .69.

CONCLUSIONS

DT correlates inversely with Tmax perfusion deficits and mismatch volumes and acts as an independent predictor of target mismatch.

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.

Favorable Bridging Therapy Based on DWI-FLAIR Mismatch in Patients with Unclear-Onset Stroke

BACKGROUND AND PURPOSE

Standard selection criteria for revascularization therapy usually exclude patients with unclear-onset stroke. Our aim was to evaluate the efficacy and safety of revascularization therapy in patients with unclear-onset stroke in the anterior circulation and to identify the predictive factors for favorable clinical outcome.

MATERIALS AND METHODS

We retrospectively analyzed 41 consecutive patients presenting with acute stroke with unknown time of onset treated by intravenous thrombolysis and/or mechanical thrombectomy. Only patients without well-developed fluid-attenuated inversion recovery changes of acute diffusion lesions on MR imaging were enrolled. Twenty-one patients were treated by intravenous thrombolysis; 19 received, simultaneously, intravenous thrombolysis and mechanical thrombectomy (as a bridging therapy); and 1 patient, endovascular therapy alone. Clinical outcome was evaluated at 90 days by using the mRS. Mortality and symptomatic intracranial hemorrhage were also reported.

RESULTS

Median patient age was 72 years (range, 17-89 years). Mean initial NIHSS score was 14.5 ± 5.7. Successful recanalization (TICI 2b-3) was assessed in 61% of patients presenting with an arterial occlusion, symptomatic intracranial hemorrhage occurred in 2 patients (4.9%), and 3 (7.3%) patients died. After 90 days, favorable outcome (mRS 0-2) was observed in 25 (61%) patients. Following multivariate analysis, initial NIHSS score (OR, 1.43; 95% CI, 1.13-1.82; P = .003) and bridging therapy (OR, 37.92; 95% CI, 2.43-591.35; P = .009) were independently associated with a favorable outcome at 3 months.

CONCLUSIONS

The study demonstrates the safety and good clinical outcome of acute recanalization therapy in patients with acute stroke in the anterior circulation and an unknown time of onset and a DWI/FLAIR mismatch on imaging. Moreover, bridging therapy versus intravenous thrombolysis alone was independently associated with favorable outcome at 3 months.

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.

Characteristics of Misclassified CT Perfusion Ischemic Core in Patients with Acute Ischemic Stroke

BACKGROUND

CT perfusion (CTP) is used to estimate the extent of ischemic core and penumbra in patients with acute ischemic stroke. CTP reliability, however, is limited. This study aims to identify regions misclassified as ischemic core on CTP, using infarct on follow-up noncontrast CT. We aim to assess differences in volumetric and perfusion characteristics in these regions compared to areas that ended up as infarct on follow-up.

MATERIALS AND METHODS

This study included 35 patients with >100 mm brain coverage CTP. CTP processing was performed using Philips software (IntelliSpace 7.0). Final infarct was automatically segmented on follow-up noncontrast CT and used as reference. CTP and follow-up noncontrast CT image data were registered. This allowed classification of ischemic lesion agreement (core on CTP: rMTT≥145%, aCBV<2.0 ml/100g and infarct on follow-up noncontrast CT) and misclassified ischemic core (core on CTP, not identified on follow-up noncontrast CT) regions. False discovery ratio (FDR), defined as misclassified ischemic core volume divided by total CTP ischemic core volume, was calculated. Absolute and relative CTP parameters (CBV, CBF, and MTT) were calculated for both misclassified CTP ischemic core and ischemic lesion agreement regions and compared using paired rank-sum tests.

RESULTS

Median total CTP ischemic core volume was 49.7ml (IQR:29.9ml-132ml); median misclassified ischemic core volume was 30.4ml (IQR:20.9ml-77.0ml). Median FDR between patients was 62% (IQR:49%-80%). Median relative mean transit time was 243% (IQR:198%-289%) and 342% (IQR:249%-432%) for misclassified and ischemic lesion agreement regions, respectively. Median absolute cerebral blood volume was 1.59 (IQR:1.43-1.79) ml/100g (P<0.01) and 1.38 (IQR:1.15-1.49) ml/100g (P<0.01) for misclassified ischemic core and ischemic lesion agreement, respectively. All CTP parameter values differed significantly.

CONCLUSION

For all patients a considerable region of the CTP ischemic core is misclassified. CTP parameters significantly differed between ischemic lesion agreement and misclassified CTP ischemic core, suggesting that CTP analysis may benefit from revisions.

Quantifying the Benefit of Prehospital Rapid Treatment in Acute Stroke

Background and Purpose—

In acute ischemic stroke, time from onset to tissue-type plasminogen activator treatment (OTT) is a major determinant of outcome. To reduce OTT, clinical trials have been undertaken evaluating prehospital cerebral imaging with mobile computed tomographic scanners. Furthermore, blood biomarkers may allow rapid differentiation between ischemic stroke and intracerebral hemorrhage before hospital admission. How such treatment strategies translate into clinical benefit has not been specifically evaluated.

Methods—

We constructed decision models to estimate the net clinical benefit yielded by shorter OTT. In different scenarios, we estimated the proportion of patients with favorable outcome and the average quality of life.

Results—

An OTT reduction of 60 minutes increases the probability of favorable outcome by 6.6% in a mixed stroke population. For comparison, the average effect of tissue-type plasminogen activator itself is 7.0%. Prehospital mobile computed tomography gaining 25 to 40 minutes increases the probability of favorable outcome by 3.0% to 4.6%. The additional benefit of prehospital computed tomography to deliver patients with large vessel occlusion directly to endovascular treatment centers increases the probability of favorable outcome by another 0.2% to 1.0%. A blood test discriminating ischemic stroke and intracerebral hemorrhage may beneficially substitute brain scan before tissue-type plasminogen activator if >32 to 40 minutes are gained and if sensitivity for intracerebral hemorrhage is >75% to 80%.

Conclusions—

Reducing the OTT has robust beneficial effects for acute stroke patients. Prehospital tissue-type plasminogen activator treatment without brain imaging may become conceivable under several preconditions, including a point-of-care test with >75% to 80% sensitivity to detect intracerebral hemorrhage and a time gain of >32 to 40 minutes. Ethical implications remain to be addressed.

An in vitro porcine model evaluating a novel stent retriever for thrombectomy of the common carotid artery

OBJECTIVES

This study aimed to test the safety and efficiency of a novel stent retriever, RECO, in a swine model.

BACKGROUND

The stent retrievers show great benefit for patients with acute ischemic stroke.

METHODS

The framework of the stent was optimized. The proximal stent was closed; mechanical connection replaced the electrolysis connection and the push wire located on the longitudinal axis. After tests in vitro, the safety and thrombectomy efficiency of RECO device were evaluated by angiography and histological analysis in a swine model with placement of experimental soft or hard thrombi.

RESULTS

No device-related thrombi were observed on the perioperative term or 1 month later. The endothelial cells were intact and the smooth muscle cells did not migrate or proliferate. Device-related vasospasm was detected in 9% vessels undergoing the procedure and was alleviated after delivery of a dose of nitroglycerin. The RECO device demonstrated a high recanalization rate in the target vessels with a mean of 1.3 runs. No residual thrombi were observed under the DSA or microscope.

CONCLUSIONS

Our data indicated that RECO device was a novel, safe and effective stent based clot retriever. A phase IIa clinical trial, RESTORE, is undergoing (NCT01983644).

Neuroinflammatory biomarkers: From stroke diagnosis and prognosis to therapy

Stroke is the third leading cause of death in industrialized countries and one of the largest causes of permanent disability worldwide. Therapeutic options to fight stroke are still limited and the only approved drug is tissue-plasminogen activator (tPA) and/or mechanical thrombectomy. Post-stroke inflammation is well known to contribute to the expansion of the ischemic lesion, whereas its resolution stimulates tissue repair and neuroregeneration processes. As inflammation highly influences susceptibility of stroke patients to overcome the disease, there is an increasing need to develop new diagnostic, prognostic and therapeutic strategies for post-stroke inflammation. This review provides a brief overview of the contribution of the inflammatory mechanisms to the pathophysiology of stroke. It specially focuses on the role of inflammatory biomarkers to help predicting stroke patients' outcome since some of those biomarkers might turn out to be targets to be therapeutically altered overcoming the urgent need for the identification of potent drugs to modulate stroke-associated inflammation. This article is part of a Special Issue entitled: Neuro Inflammation edited by Helga E. de Vries and Markus Schwaninger.

Histological examination of vascular damage caused by stent retriever thrombectomy devices

Background and objectives

Although the recently marketed stent retriever thrombectomy devices have demonstrated a high recanalization rate and favorable clinical outcomes, there is a concern about the risks of intimal injuries when pulling out the stent in the unfolded position. In this study, the Solitaire Flow Restoration System and the Trevo retriever were used in a histopathological comparison of vascular injuries caused by stent retriever thrombectomy devices.

Methods

Rabbit carotid arteries were used in the experiments with stent retriever thrombectomy devices. Carotid artery samples were harvested either 1 or 2 weeks postoperatively for histological examination.

Results

Histological changes caused by the use of stent retriever thrombectomy devices were observed from the intimal to medial layers. With the Solitaire FR 4 mm, intimal and medial thickening was observed 1 week postoperatively, and progression of intimal thickening was observed 2 weeks postoperatively. The extent of intimal thickening tended to be greater with the Solitaire FR 6 mm than with the Solitaire FR 4 mm, but this difference was not significant. Compared with the Solitaire FR 4 mm, the Trevo had a significantly smaller area of intimal thickening.

Conclusions

Although there are some differences among devices, results from this study indicate that stent retriever thrombectomy devices induce vascular damage that extends to the medial layer.

Benefits of Stroke Treatment Using a Mobile Stroke Unit Compared With Standard Management: The BEST-MSU Study Run-In Phase

BACKGROUND AND PURPOSE

Faster treatment with intravenous tissue-type plasminogen activator (tPA) is likely to improve outcomes. Optimizing prehospital triage by mobile stroke units (MSUs) may speed treatment times. The Benefits of Stroke Treatment Delivered Using a Mobile Stroke Unit (BEST-MSU) study was launched in May 2014 using the first MSU in the United States to compare stroke management using an MSU versus standard management (SM). Herein, we describe the results of the prespecified, nonrandomized run-in phase designed to obtain preliminary data on study logistics.

METHODS

The run-in phase consisted of 8 MSU weeks when all-patient care occurred on the MSU and 2 SM weeks when the MSU nurse met personnel on scene or at the emergency department to ensure comparability with MSU patients. Telemedicine was independently performed in 9 MSU cases.

RESULTS

Of 130 alerts, 24 MSU and 2 SM patients were enrolled. Twelve of 24 MSU patients received tPA on board; 4 were treated within 60 minutes of last seen normal, and 4 went on to endovascular treatment. There were no hemorrhagic complications. Four had primary intracerebral hemorrhage. Agreement on tPA eligibility between the onsite and telemedicine physician was 90%.

CONCLUSIONS

The run-in phase provided a tPA treatment rate of 1.5 patients per week, assured us that treatment within 60 minutes of onset is possible, and enabled enrollment of patients on SM weeks. We also recognized the opportunity to assess the effect of the MSU on endovascular treatment and intracerebral hemorrhage. Challenges include the need to control biased patient selection on MSU versus SM weeks and establish inter-rater agreement for tPA treatment using telemedicine.

Stent-based thrombectomy versus intravenous tissue plasminogen activator in acute ischaemic stroke: A systematic review and meta-analysis

PURPOSE

To date only a few studies have compared the effectiveness and functional outcomes of stent retrievers versus intravenous thrombolysis in acute ischaemic stoke. Our aim was to identify and collate all the available data and to assess for statistical differences in patient outcomes between the two treatments.

MATERIALS AND METHODS

We performed a systematic review and meta-analysis of studies with a randomised controlled design which utilised stentrievers and intravenous thrombolysis in acute ischaemic stroke.

RESULTS

Five randomised controlled studies published in 2015 were identified. Second-generation thrombectomy devices constituted at least 80% of thrombectomy devices in the included studies, namely MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME and REVASCAT. No significant heterogeneity was seen in the included studies and the five trials were therefore included in the meta-analysis.A total of 46.10% of patients treated with stentrievers achieved an independent functional outcome (mRS < 2) at 90 days compared with 26.46% of those treated with intravenous thrombolysis with an odds ratio of 2.40 (p < 0.001). The weighted recanalisation mean in the thrombectomy arms was 76.02%.A lower mortality rate was observed with stentrievers compared to intravenous thrombolysis (15.33% vs 18.74%; OR 0.81, p = 0.15). Stentrievers were also associated with a lower risk of symptomatic intracranial haemorrhage (7.86% vs 8.64%; OR 1.02, p = 0.93). The differences in the secondary/safety outcomes were not statistically significant.

CONCLUSION

Stentrievers can achieve a high rate of recanalisation and functional independence in acute ischaemic stroke and have a relatively good safety profile. Our meta-analysis demonstrates a clear benefit of an intra-arterial mechanical approach vs standard treatment.

Mechanical thrombectomy in patients with acute basilar occlusion using stent retrievers

BACKGROUND

Early arterial recanalisation with stent retrievers (SR) has been recently demonstrated to improve clinical outcome of patients with large-vessel occlusion of the anterior circulation. However, the benefit of SR thrombectomy in the setting of acute basilar artery occlusion (BAO) has not been proven yet. This study evaluated a series of consecutive patients with BAO treated with SR, focusing on the efficacy, safety and clinical results.

METHODS

We analysed 24 consecutive patients with acute BAO who were treated with SR mechanical thrombectomy. Good clinical outcome at three months was defined as mRS ≤ 2. Data from patients with good outcome were compared to that from patients with poor outcome.

RESULTS

Sufficient recanalisation (TICI 2 b or 3) was achieved in 63% (15/24) of patients. At three months, 33% (8/24) of patients had died; good clinical outcome was obtained in 21% (5/24). Age (46 vs. 60 years old, p = 0.05) and time from symptoms onset to recanalisation (370 vs. 521 minutes, p = 0.048) was significantly lower in patients with good outcome as compared to patients with poor outcome. There were three cases (12.5%) of periprocedural complications, all of them related to arterial wall dissection/perforation.

CONCLUSIONS

SR thrombectomy might be an efficient and safe treatment for patients with acute BAO occlusion and might help improve outcome.

Intravenous tissue plasminogen activator before endovascular treatment increases symptomatic intracranial hemorrhage in patients with occlusion of the middle cerebral artery second division: subanalysis of the RESCUE-Japan Registry

INTRODUCTION

No previous study has investigated the relationship between intravenous tissue plasminogen activator (IV t-PA) and intracranial hemorrhage (ICH) according to the location of vessel occlusion. The aim of the present study was to investigate the relationship between preprocedural IV t-PA and endovascular treatment (EVT) and ICH according to the location of occlusion using data from the nationwide prospective registry of acute cerebral large vessel occlusion (LVO), the RESCUE-Japan Registry.

METHODS

Among 1442 patients with acute LVO enrolled in the registry, we examined 410 patients who received EVT. Patients were divided into the following four groups according to the location of occlusion: the internal carotid artery (ICA), middle cerebral artery first division (M1), middle cerebral artery second division (M2), and vertebral artery (VA)/basilar artery (BA) groups.

RESULTS

A total of 399 patients in whom the occlusion was located in these vessels were finally included. Any ICH (aICH) was identified in 127 (30.9%) patients, and symptomatic ICH (sICH) was identified in 20 (4.9%). Preprocedural IV t-PA did not increase the incidence of aICH in any group and tended to increase the incidence of sICH in only the M2 group. In multivariate analysis of the M2 group, IV t-PA was an independent risk factor for sICH.

CONCLUSION

Preprocedural IV t-PA did not increase the incidence of ICH in total, but could increase the incidence of sICH in those with M2 occlusion. IV t-PA before EVT may be an independent risk factor for sICH in patients with M2 occlusion.

Primary stent retrieval for acute intracranial large artery occlusion due to atherosclerotic disease

BACKGROUND AND PURPOSE

The goal of stent retriever-based thrombectomy is removal of embolic clots in patients with intracranial large artery occlusion. However, outcomes of stent retrieval may differ between acute arterial occlusions due to intracranial atherosclerotic disease (IAD) and those due to embolism. This case series describes the outcomes of stent retriever-based thrombectomy and rescue treatments in 9 patients with IAD-related occlusion.

METHODS

Among patients who underwent endovascular treatment for acute intracranial large artery occlusion, those in whom stent retrieval was attempted as first-line treatment were included in this review. IAD was defined as significant fixed focal stenosis at the occlusion site, which was evident on final angiographic assessment or observed during endovascular treatment.

RESULTS

Median number of stent retriever passes was 2 (range, 1-3), and temporary bypass was seen in all patients. Immediate partial recanalization (arterial occlusive lesion grade 2-3) was observed in 7 patients. Immediate modified thrombolysis in cerebral infarction grade 2b-3 was seen in 6 patients, but the lesions often required rescue treatment due to reocclusion or flow insufficiency. In terms of rescue treatments, angioplasty and intra-arterial tirofiban infusion seemed to be effective.

CONCLUSIONS

Our findings suggest that stent retrieval can effectively remove thrombi from stenotic lesions and achieve partial recanalization despite the tendency toward reocclusion in most patients with IAD-related occlusion. Further research into the use of rescue treatments, such as tirofiban infusion and angioplasty, is warranted.

Sex Differences in Long-Term Survival after a First Stroke with Intravenous Thrombolysis: Ebrictus Study

Background

A number of large trials have confirmed the benefits of thrombolysis in acute stroke, but there are gender differences. We sought to examine the relationship between sex and outcome after thrombolysis.

Methods

This was a prospective cohort study including 1,272 incident ischemic strokes (597 in women) from April 1, 2006 to December 31, 2014. Statistical approaches were used for analyzing survival outcomes and their relationship with thrombolysis therapy.

Results

The death rates were lower (p = 0.003) in the thrombolysis therapy group with an incidence ratio of 0.57 (95% CI 0.39-0.83). 113 (8.8%) patients (53 women) received thrombolysis. They were significantly younger (69.2 ± 12.7 vs. 73.9 ± 12.5 years; p < 0.001), had higher NIHSS score (12.7 ± 6.3 vs. 7.3 ± 7.0; p < 0.001), spent more days in hospital (10.4 ± 8.3 vs. 8.3 ± 7.9; p < 0.001), and had a higher average Barthel score at discharge (85.5 ± 24.4 vs. 79.2 ± 28.6; p = 0.023). The male/female incidence ratio showed a significant decrease (p = 0.01) in the incidence of mortality in women and a better Barthel score. The thrombolysis improved the survival in the overall group with thrombolysis versus without thrombolysis (p = 0.028), in women versus in men with thrombolysis (p = 0.023), and in women with thrombolysis versus in those without thrombolysis (p < 0.001) but not in men with thrombolysis versus in those without thrombolysis (p = 0.743). The protective factors as regards mortality were thrombolysis therapy (95% CI 0.37-0.80; p = 0.002), Barthel score ≥60 (95% CI 0.81-0.94; p = 0.002), and cardiovascular secondary prevention 1 year after stroke (0.13, 95% CI 0.06-0.28).

Conclusions

The stroke death rates were lower in women after thrombolysis treatment and suggest significant benefit for women in this setting. The overall benefit on survival of the patients treated with thrombolysis might be explained by the beneficial effect of the thrombolysis on the women.

Early Loss of Immediate Reperfusion While Stent Retriever in Place Predicts Successful Final Reperfusion in Acute Ischemic Stroke Patients

BACKGROUND AND PURPOSE

Degree of stent retriever engagement with target thrombi may be reflected by (1) immediate reperfusion (IR) on first deployment, indicating displacement of clot toward the vessel wall, and (2) by early loss of IR (ELOIR), indicating penetration of retriever struts through the thrombus. The relation of these early findings to final reperfusion and clinical outcomes has not been well delineated.

METHODS

We investigated IR and ELOIR in patients undergoing stent retriever mechanical thrombectomy at an academic medical center between March 2012 and June 2014.

RESULTS

Among 56 patients, IR itself was not associated with final successful reperfusion, which occurred in 66.7% of IR patients and 71.4% of non-IR patients (P=0.999). However, ELOIR was associated with a higher rate of final successful reperfusion (92% versus 44%; P=0.046). Patients with ELOIR had a higher nominal rate of final favorable outcome (42% versus 22%; P=0.64).

CONCLUSIONS

ELOIR during the embedding period after deployment of stent retrievers is associated with successful final reperfusion, likely because of greater thrombus engagement with the stent retriever. ELOIR may be a useful finding to guide duration of embedding time in clinical practice and design of novel stent retrievers.

[Mechanical thrombectomy for acute ischemic stroke : current evidence and open questions]

OBJECTIVE

To determine the importance of mechanical thrombectomy (MT) in the treatment of ischemic stroke.

MATERIAL AND METHODS

Analysis and comparison of randomized controlled trials (RCT) of MT versus i.v. thrombolysis (IVT) considering pathophysiological and logistic aspects.

RESULTS

The use of MT is more effective than IVT for internal carotid artery terminus (ICAT), M1 segment and tandem occlusions, i.e. proximal internal carotid artery (ICA) occlusion or stenosis, even in patients older than 75-80 years of age. Due to the small sample sizes this question cannot be answered for patients with M2 occlusions. It is still uncertain whether MT is needed in patients with a low National Institutes of Health stroke scale (NIHSS) score, whether IVT is needed before MT and what type of imaging should be performed. Approximately one third of eligible patients currently undergo MT in Germany. Results from RCTs with stent retrievers for patients with vertebrobasilar artery occlusions are lacking.

CONCLUSION

After becoming established as a first-line therapy for patients with ICAT, M1 segment and tandem occlusions, the effectiveness of MT with stent retrievers has to proven in patients with more distal occlusions, low NIHSS scores and even vertebrobasilar artery occlusions.