Younger Stroke Patients With Large Pretreatment Diffusion-Weighted Imaging Lesions May Benefit From Endovascular Treatment

Outcome After Reperfusion Therapies in Patients With Large Baseline Diffusion-Weighted Imaging Stroke Lesions

Background and Purpose—

Stroke patients with large diffusion-weighted imaging (DWI) volumes are often excluded from reperfusion because of reckoned futility. In those with DWI volume >70 mL, included in the THRACE trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke), we report the associations between baseline parameters and outcome.

Methods—

We examined 304 patients with anterior circulation stroke and pretreatment magnetic resonance imaging. Variables were extracted from the THRACE database, and DWI volumes were measured semiautomatically.

Results—

Among 53 patients with DWI volume >70 mL, 12 had favorable outcome (modified Rankin Scale score, ≤2) at 3 months; they had less coronary disease (0/12 versus 12/38; P =0.046) and less history of smoking (1/10 versus 12/31; P =0.013) than patients with modified Rankin Scale score >2. None of the 8 patients >75 years of age reached modified Rankin Scale score ≤2. Favorable outcome occurred in 12 of 37 M1-occluded patients but in 0 of 16 internal carotid-T/L–occluded patients ( P =0.010). Favorable outcome was more frequent (6/13) when DWI lesion was limited to the superficial middle cerebral artery territory than when it extended to the deep middle cerebral artery territory (6/40; P =0.050).

Conclusions—

Stroke patients with DWI lesion >70 mL may benefit from reperfusion therapy, especially those with isolated M1 occlusion or ischemia restricted to the superficial middle cerebral artery territory. The benefit of treatment seems questionable for patients with carotid occlusion or lesion extending to the deep middle cerebral artery territory.

Mechanical Thrombectomy in Anterior Circulation Occlusion Could Be More Effective than Medical Management Even in Low DWI-ASPECTS Patients

The purpose of this study was to investigate whether patients with low preoperative Diffusion-weighted Imaging Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) could benefit from mechanical thrombectomy for acute anterior circulation occlusion. This was a retrospective, non-blinded, cohort study. From September 2012 to August 2016, 83 consecutive patients of acute anterior circulation occlusion were treated with thrombectomy using second-generation devices or medical management. The DWI-ASPECTS was scored after the first MRI. Patient characteristics and clinical outcomes were compared between the treatment groups. Significant dependence was defined as a modified Rankin scale score ≥3 at 90 days. As a result, 33 patients underwent mechanical thrombectomy and 50 received medical management. In the mechanical thrombectomy group, the variable of lower DWI-ASPECTS (5, 4–6 vs. 8, 7–8, P < 0.001), especially ≤6, was significantly associated with poor prognosis. However, compared with patients of DWI-ASPECTS ≤ 6 who received medical management, there were significantly fewer patients with poor outcomes in thrombectomy (dependent in 11 of 15 vs. 23 of 23, respectively; P = 0.019). Although patients with lower pretreatment DWI-ASPECTS could benefit less from thrombectomy, their outcomes were still better than medical management. Therefore, mechanical thrombectomy could be considered in some patients with low pretreatment DWI-ASPECTS.

Fibrin Clot Architecture in Acute Ischemic Stroke Treated With Mechanical Thrombectomy With Stent-Retrievers - Cohort Study

BACKGROUND

The composition of intra-arterial clots might influence the efficacy of mechanical thrombectomy (MT) in ischemic stroke (IS) due to the acute occlusions within large cerebral arteries. The aims were to assess the factors associated with blood clot structure and the impact of thromboembolus structure on MT using stent-retrievers in patients with acute large artery IS in the anterior circulation.Methods and Results:In an observational cohort study, we studied the components of intra-arterial clots retrieved from large cerebral arteries in 80 patients with acute IS treated with MT with or without i.v. thrombolysis (IVT). Histology of the clots was carried out without knowledge of the clinical findings, including the treatment methods. The components of the clots, their age, origin and semi-quantitative graded changes in the architecture of the fibrin components (e.g., "thinning") were compared via neuro-interventional, clinical and laboratory data. The most prominent changes in the architecture of the fibrin components in the thromboemboli were associated with IVT (applied in 44 patients; OR, 3.50; 95% CI: 1.21-10.10, P=0.02) and platelet count (OR, 2.94; 95% CI: 1.06-8.12, P=0.04).

CONCLUSIONS

In patients with large artery IS treated with the MT using stent-retrievers, bridging therapy with IVT preceding MT and higher platelet count were associated with significant changes of the histological structure of blood clots.

Clinical Imaging Factors Associated With Infarct Progression in Patients With Ischemic Stroke During Transfer for Mechanical Thrombectomy

Importance

When transferred from a referring hospital (RH) to a thrombectomy-capable stroke center (TCSC), patients with initially favorable imaging profiles (Alberta Stroke Program Early CT Score [ASPECTS] ≥6) often demonstrate infarct progression significant enough to make them ineligible for mechanical thrombectomy at arrival. In rapidly evolving stroke care networks, the question of the need for vascular imaging at the RHs remains unsolved, resulting in an important amount of futile transfers for thrombectomy.

Objective

To examine the clinical imaging factors associated with unfavorable imaging profile evolution for thrombectomy in patients with ischemic stroke initially transferred to non-TCSCs.

Design, Setting, and Participants

Data from patients transferred from 1 of 30 RHs in our regional stroke network and presenting at our TCSC from January 1, 2010, to January 1, 2016, were retrospectively analyzed. Consecutive patients with acute ischemic stroke initially admitted to a non-thrombectomy-capable RH and transferred to our center for which a RH computed tomography (CT) and a CT angiography (CTA) at arrival were available for review.

Main Outcomes and Measures

ASPECTS were evaluated. The adequacy of leptomeningeal collateral blood flow was rated as no or poor, decreased, adequate, or augmented per the adapted Maas scale. The main outcome was an ASPECTS decay, defined as an initial ASPECTS of 6 or higher worsening between RH and TCSC CTs to a score of less than 6 (making the patient less likely to derive clinical benefit from thrombectomy at arrival).

Results

A total of 316 patients were included in the analysis (mean [SD] age, 70.3 [14.2] years; 137 [43.4%] female). In multivariable models, higher National Institutes of Health Stroke Score, lower baseline ASPECTSs, and no or poor collateral blood vessel status were associated with ASPECTS decay, with collateral blood vessel status demonstrating the highest adjusted odds ratio of 5.14 (95% CI, 2.20-12.70; P < .001). Similar results were found after stratification by vessel occlusion level.

Conclusions and Relevance

In patients with ischemic stroke transferred for thrombectomy, poor collateral blood flow and stroke clinical severity are the main determinants of ASPECTS decay. Our findings suggest that in certain subgroups vascular imaging, including collateral assessment, can play a crucial role in determining the benefits of transfer for thrombectomy.

Improving Regional Stroke Systems of Care

PURPOSE OF REVIEW

Acute ischemic stroke (AIS) care is rapidly evolving. This review discusses current diagnostic, therapeutic, and process models that can expedite stroke treatment to achieve best outcomes.

RECENT FINDINGS

Use of stent retrievers after selection via advanced imaging is safe and effective, and is an important option for AIS patients with large vessel occlusion (LVO). Significant time delays occur before and during patient transfers, and upon comprehensive stroke center (CSC) arrival, and have deleterious effects on functional outcome. Removing obstacles, enhancing inter-facility communication, and creating acute stroke management processes and protocols are paramount strategies to enhance network efficiency. Inter-departmental CSC collaboration can significantly reduce door-to-treatment times. Streamlined stroke systems of care may result in higher treatment rates and better functional outcomes for AIS patients, simultaneously conserving healthcare dollars. Stroke systems of care should be structured regionally to minimize time to treatment. A proactive approach must be employed; a management plan incorporating stroke team prenotification and parallel processes between departments can save valuable time, maximize brain salvage, and reduce disability from stroke.

Endovascular Treatment of Spontaneous Intracranial Internal Carotid Dissection in a Young Patient Affected by Systemic Lupus Erythematosus: A Case Report

Systemic lupus erythematosus (SLE) increases the risk of cerebrovascular events due to vascular changes, resulting in the weakening of the vessel walls. Moreover, patients with SLE have more incidence of arterial lesions such as dissections. Internal carotid dissection (ICA) is an infrequent cause of ischemic stroke, representing 2% of all ischemic events. We present a case of ischemic stroke, caused by a spontaneous dissection of intracranial ICA, treated with endovascular stent implantation, in a 22-year-old woman affected by SLE, newly diagnosed. ICA dissection with consequent ischemic stroke is an unusual first presentation of SLE disease. Our case highlights how, despite an infrequent occurrence, ICA dissection should be considered for young adults presenting with ischemic stroke, especially in those affected by SLE. This paper also shows the good technical result in the use of stenting in case of intracranial ICA dissection.

Focal T2 and FLAIR hyperintensities within the infarcted area: A suitable marker for patient selection for treatment?

Background and purpose

Some authors use FLAIR imaging to select patients for stroke treatment. However, the effect of hyperintensity on FLAIR images on outcome and bleeding has been addressed in only few studies with conflicting results.

Methods

466 patients with anterior circulation strokes were included in this study. They all were examined with MRI before intravenous or endovascular treatment. Baseline data and 3 months outcome were recorded prospectively. Focal T2 and FLAIR hyperintensities within the ischemic lesion were evaluated by two raters, and the PROACT II classification was applied to assess bleeding complications on follow up imaging. Logistic regression analysis was used to determine predictors of bleeding complications and outcome and to analyze the influence of T2 or FLAIR hyperintensity on outcome.

Results

Focal hyperintensities were found in 142 of 307 (46.3%) patients with T2 weighted imaging and in 89 of 159 (56%) patients with FLAIR imaging. Hyperintensity in the basal ganglia, especially in the lentiform nucleus, on T2 weighted imaging was the only independent predictor of any bleeding after reperfusion treatment (33.8% in patients with vs. 18.2% in those without; p = 0.003) and there was a non-significant trend for more bleedings in patients with FLAIR hyperintensity within the basal ganglia (p = 0.069). However, there was no association of hyperintensity on T2 weighted or FLAIR images and symptomatic bleeding or worse outcome.

Conclusion

Our results question the assumption that T2 or FLAIR hyperintensities within the ischemic lesion should be used to exclude patients from reperfusion therapy, especially not from endovascular treatment.

Blood Pressure and Penumbral Sustenance in Stroke from Large Vessel Occlusion

The global burden of stroke remains high, and of the various subtypes of stroke, large vessel occlusions (LVOs) account for the largest proportion of stroke-related death and disability. Several randomized controlled trials in 2015 changed the landscape of stroke care worldwide, with endovascular thrombectomy (ET) now the standard of care for all eligible patients. With the proven success of this therapy, there is a renewed focus on penumbral sustenance. In this review, we describe the ischemic penumbra, collateral circulation, autoregulation, and imaging assessment of the penumbra. Blood pressure goals in acute stroke remain controversial, and we review the current data and suggest an approach for induced hypertension in the acute treatment of patients with LVOs. Finally, in addition to reperfusion and enhanced perfusion, efforts focused on developing therapeutic targets that afford neuroprotection and augment neural repair will gain increasing importance. ET has revolutionized stroke care, and future emphasis will be placed on promoting penumbral sustenance, which will increase patient eligibility for this highly effective therapy and reduce overall stroke-related death and disability.

Successful Reperfusion With Mechanical Thrombectomy Is Associated With Reduced Disability and Mortality in Patients With Pretreatment Diffusion-Weighted Imaging–Alberta Stroke Program Early Computed Tomography Score ≤6

Background and Purpose—

In acute ischemic stroke patients, diffusion-weighted imaging (DWI)–Alberta Stroke Program Early Computed Tomography Score (ASPECTS) is correlated with infarct volume and is an independent factor of functional outcome. Patients with pretreatment DWI-ASPECTS ≤6 were excluded or under-represented in the recent randomized mechanical thrombectomy trials. Our aim was to assess the impact of reperfusion in pretreatment DWI-ASPECTS ≤6 patients treated with mechanical thrombectomy.

Methods—

We analyzed data collected between January 2012 and August 2015 in a bicentric prospective clinical registry of consecutive acute ischemic stroke patients treated with mechanical thrombectomy. Every patient with a documented internal carotid artery or middle cerebral artery occlusion with pretreatment DWI-ASPECTS ≤6 was eligible for this study. The primary end point was a favorable outcome defined by a modified Rankin Scale score ≤2 at 90 days.

Results—

Two hundred and eighteen patients with a DWI-ASPECTS ≤6 were included. Among them, 145 (66%) patients had successful reperfusion at the end of mechanical thrombectomy. Reperfused patients had an increased rate of favorable outcome (38.7% versus 17.4%; P =0.002) and a decreased rate of mortality at 3 months (22.5% versus 39.1%; P =0.013) compared with nonreperfused patients. The symptomatic intracranial hemorrhage rate was not different between the 2 groups (13.0% versus 14.1%; P =0.83). However, in patients with DWI-ASPECTS <5, favorable outcome was low (13.0% versus 9.5%; P =0.68) with a high mortality rate (45.7% versus 57.1%; P =0.38) with or without successful reperfusion.

Conclusions—

Successful reperfusion is associated with reduced mortality and disability in patients with a pretreatment DWI-ASPECTS ≤6. Further data from randomized studies are needed, particularly in patients with DWI-ASPECTS <5.

Diffusion and Perfusion MR Imaging in Acute Stroke: Clinical Utility and Potential Limitations for Treatment Selection

Magnetic resonance (MR) diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) offer unique insight into acute ischemic stroke pathophysiology. These techniques may offer the ability to apply pathophysiology to accurately individualize acute stroke reperfusion treatment, including extending the opportunity of reperfusion treatment to well beyond the current time-based treatment windows.This review examines the use of DWI and PWI in the major stroke trials, their current clinical utility, and potential limitations for reperfusion treatment selection. DWI and PWI continue to be investigated in ongoing randomized controlled trials, and continued research into these techniques will help achieve the goal of tissue-based decision making and individualized acute stroke treatment.

Outcome of patients with proximal vessel occlusion of the anterior circulation and DWI-PWI mismatch is time-dependent

BACKGROUND AND PURPOSE

Patients with ischemic stroke and large vessel occlusion are assumed to benefit from endovascular therapy (ET) independent of the symptom onset-to-treatment time (OTT) if they present with a mismatch of diffusion- and perfusion-weighted imaging (DWI-PWI mismatch). We aimed at studying the influence of OTT on clinical outcome in these patients.

METHODS

Retrospective database review in a tertiary care university hospital. All patients presented with proximal vessel occlusion of the anterior circulation and DWI-PWI mismatch. Primary outcome was the influence of OTT on modified Rankin scale (mRS) score three months after treatment, dichotomized in favourable (0-2) and unfavourable outcome (3-6). Secondary outcome was the effect of OTT on the shift of the mRS score. Patients treated within an early time window (<340min) and a late time window (≥340min) were compared.

RESULTS

139 patients were included. The rate of favourable outcome was significantly higher in patients who were treated in an early compared to those treated in a late time window (31 [49%] vs. 20 patients [27%], p=0.005). Adjusted multivariate logistic regression revealed that late treatment was an independent negative predictor of favourable outcome (odds ratio 0.39, confidence interval [0.18-0.84]; p=0.016). A shift towards higher mRS scores for late treatment was evident (p=0.015). In sensitivity analysis, OTT remained an independent predictor when evaluated as continuous variable. These findings were confirmed in patients with a comparable DWI-PWI mismatch according to the definitions from large trials (DEFUSE 2, DEFUSE 3, SWIFT-PRIME, EXTEND-IA).

CONCLUSION

Outcome of patients with comparable DWI-PWI mismatch is time-dependent.

Impact of Initial Diffusion-Weighted Imaging Lesion Growth Rate on the Success of Endovascular Reperfusion Therapy

Background and Purpose—

Initial diffusion-weighted imaging lesion growth rate (IGR) assessed by diffusion-weighted imaging lesion volume divided by the delay from onset to magnetic resonance imaging offers an estimate of early brain infarction progression. We investigated the impact of IGR on the rate of favorable outcome according to the occurrence of a successful endovascular revascularization within 6 hours after onset in patients experiencing an acute brain infarction complicating internal carotid artery terminus/middle cerebral artery M1 occlusion.

Methods—

The primary study end point was a favorable outcome defined by a modified Rankin Scale score of ≤2, 90 days after onset. A Thrombolysis in Cerebral Infarction score 2b/3 defined a successful recanalization.

Results—

A total of 166 patients were included. Median IGR was 7 mL/h (interquartile range, 2–26). Sixty-eight patients (41%) experienced a favorable outcome. After adjustment on age, systolic blood pressure, vessel site occlusion, National Institutes of Health Stroke Scale, and antithrombotic medication, increase in IGR was associated with a decreased occurrence of favorable outcome with an odds ratio per SD increase of 0.60 (95% confidence interval, 0.38–0.94; P =0.03). A successful recanalization was achieved among 56% of the patients after a median delay of 251 minutes (interquartile range, 211–291 minutes). Increasing IGR was associated with a decreased favorable outcome only when a successful recanalization was not achieved (adjusted odds ratio, 0.32; 95% confidence interval, 0.12–0.85; P =0.02).

Conclusions—

Proximal internal carotid artery/M1 occlusion did result into a wide range of IGR within 6 hours after onset. Increasing IGR was associated with a lower rate of favorable outcome after endovascular treatment overall and when a successful recanalization was not achieved.

Third European Stroke Science Workshop

Lake Eibsee, Garmisch-Partenkirchen, November 19 to 21, 2015: The European Stroke Organization convened >120 stroke experts from 27 countries to discuss latest results and hot topics in clinical, translational, and basic stroke research. Since its inception in 2011, the European Stroke Science Workshop has become a cornerstone of European Stroke Organization's academic activities and major highlight for researchers in the field. Participants include stroke researchers at all career stages who convene for plenary lectures and discussions, thus facilitating crosstalk among researchers from different fields. As in previous years, the workshop was organized into 7 scientific sessions each focusing on a major research topic. All sessions started with a keynote lecture that provided an overview on current developments and set the scene for the following presentations. The latter were short focused talks on a timely topic and included the most recent findings, including unpublished data. A new element at this year's meeting was a hot topic session in which speakers had to present a provocative concept or update sharply within 5 minutes. In the following, we summarize the key contents of the meeting. The program is provided in the online-only Data Supplement.

The Evolution of Mechanical Thrombectomy for Acute Stroke

OPINION STATEMENT

The natural history of an acute ischemic stroke from a large vessel occlusion (LVO) is poor and has long challenged stroke therapy. Recently, endovascular therapy has demonstrated superiority to medical management in appropriately selected patients. This advance has revolutionized acute care for LVO and mandates a reevaluation of the entire chain of stroke care delivery, including patient selection, intervention, and post-procedural care. Since endovascular therapy is a therapy specifically targeting LVO, its application should be restricted to those patients only. Clinical and radiologic parameters need to be considered in patient selection. Data supports that all patients over the age of 18 years presenting with a National Institutes of Health Stroke Scale (NIHSS) of 6 or greater within 6 hours of symptom onset should be considered for emergent endovascular therapy. Radiologically, those with a LVO of the internal carotid artery (ICA) or middle cerebral artery (MCA) M1 portion, intermediate or good collaterals and without large established infarct should be considered endovascular candidates. Selection beyond these parameters remains an open question and is being actively evaluated. In all cases, revascularization should be attempted with a new generation device (stentriever or direct aspiration), as these techniques are most likely to deliver adequate reperfusion. Post-revascularization, patients are closely monitored in an intensive care setting followed by discharge to rehabilitation, if required, or directly home. Patients should be evaluated in delayed fashion to assess recovery (typically at 3 months post-treatment). Ultimately, the poor natural history of ischemic stroke from LVO and the potential significant benefit from endovascular therapy over medical management alone necessitate a national response to ensure we identify and treat all eligible patients as rapidly and effectively as possible.

Safety and Efficacy of Solitaire Stent Thrombectomy: Individual Patient Data Meta-Analysis of Randomized Trials

BACKGROUND AND PURPOSE

Recent positive randomized trials of endovascular therapy for ischemic stroke used predominantly stent retrievers. We pooled data to investigate the efficacy and safety of stent thrombectomy using the Solitaire device in anterior circulation ischemic stroke.

METHODS

Patient-level data were pooled from trials in which the Solitaire was the only or the predominant device used in a prespecified meta-analysis (SEER Collaboration): Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME), Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE), Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial (EXTEND-IA), and 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). The primary outcome was ordinal analysis of modified Rankin Score at 90 days. The primary analysis included all patients in the 4 trials with 2 sensitivity analyses: (1) excluding patients in whom Solitaire was not the first device used and (2) including the 3 Solitaire-only trials (excluding ESCAPE). Secondary outcomes included functional independence (modified Rankin Score 0-2), symptomatic intracerebral hemorrhage, and mortality.

RESULTS

The primary analysis included 787 patients: 401 randomized to endovascular thrombectomy and 386 to standard care, and 82.6% received intravenous thrombolysis. The common odds ratio for modified Rankin Score improvement was 2.7 (2.0-3.5) with no heterogeneity in effect by age, sex, baseline stroke severity, extent of computed tomography changes, site of occlusion, or pretreatment with alteplase. The number needed to treat to reduce disability was 2.5 and for an extra patient to achieve independent outcome was 4.25 (3.29-5.99). Successful revascularization occurred in 77% treated with Solitaire device. The rate of symptomatic intracerebral hemorrhage and overall mortality did not differ between treatment groups.

CONCLUSIONS

Solitaire thrombectomy for large vessel ischemic stroke was safe and highly effective with substantially reduced disability. Benefits were consistent in all prespecified subgroups.

Endovascular thrombectomy for stroke: current best practice and future goals

Endovascular thrombectomy for large vessel ischaemic stroke substantially reduces disability, with recent positive randomised trials leading to guideline changes worldwide. This review discusses in detail the evidence provided by recent randomised trials and meta-analyses, the remaining areas of uncertainty and the future directions for research. The data from existing trials have demonstrated the robust benefit of endovascular thrombectomy for internal carotid and proximal middle cerebral artery occlusions. Uncertainty remains for more distal occlusions where the efficacy of alteplase is greater, less tissue is at risk and the safety of endovascular procedures is less established. Basilar artery occlusion was excluded from the trials, but with a dire natural history and proof of principle that rapid reperfusion is effective, it seems reasonable to continue treating these patients pending ongoing trial results. There has been no evidence of heterogeneity in treatment effect in clinically defined subgroups by age, indeed, those aged >80 years have at least as great an overall reduction in disability and reduced mortality. Similarly there was no heterogeneity across the range of baseline stroke severities included in the trials. Evidence that routine use of general anaesthesia reduces the benefit of endovascular thrombectomy is increasing and conscious sedation is generally preferred unless severe agitation or airway compromise is present. The impact of time delays has become clearer with description of onset to imaging and imaging to reperfusion epochs. Delays in the onset to imaging reduce the proportion of patients with salvageable brain tissue. However, in the presence of favourable imaging, rapid treatment appears beneficial regardless of the onset to imaging time elapsed. Imaging to reperfusion delays lead to decay in the clinical benefit achieved, particularly in those with less robust collateral flow. The brain imaging options to assess prognosis have various advantages and disadvantages, but whatever strategy is employed must be fast. Ongoing trials are investigating extended time windows, using advanced brain imaging selection. There is also a need for further technical advances to maximise rates of complete reperfusion in the minimum time.