A trial of imaging selection and endovascular treatment for ischemic stroke

Optimal Workflow and Process-Based Performance Measures for Endovascular Therapy in Acute Ischemic Stroke

Background and Purpose—

We report on workflow and process-based performance measures and their effect on clinical outcome in Solitaire FR Thrombectomy for Acute Revascularization (STAR), a multicenter, prospective, single-arm study of Solitaire FR thrombectomy in large vessel anterior circulation stroke patients.

Methods—

Two hundred two patients were enrolled across 14 centers in Europe, Canada, and Australia. The following time intervals were measured: stroke onset to hospital arrival, hospital arrival to baseline imaging, baseline imaging to groin puncture, groin puncture to first stent deployment, and first stent deployment to reperfusion. Effects of time of day, general anesthesia use, and multimodal imaging on workflow were evaluated. Patient characteristics and workflow processes associated with prolonged interval times and good clinical outcome (90-day modified Rankin score, 0–2) were analyzed.

Results—

Median times were onset of stroke to hospital arrival, 123 minutes (interquartile range, 163 minutes); hospital arrival to thrombolysis in cerebral infarction (TICI) 2b/3 or final digital subtraction angiography, 133 minutes (interquartile range, 99 minutes); and baseline imaging to groin puncture, 86 minutes (interquartile range, 24 minutes). Time from baseline imaging to puncture was prolonged in patients receiving intravenous tissue-type plasminogen activator (32-minute mean delay) and when magnetic resonance–based imaging at baseline was used (18-minute mean delay). Extracranial carotid disease delayed puncture to first stent deployment time on average by 25 minutes. For each 1-hour increase in stroke onset to final digital subtraction angiography (or TICI 2b/3) time, odds of good clinical outcome decreased by 38%.

Conclusions—

Interval times in the STAR study reflect current intra-arterial therapy for patients with acute ischemic stroke. Improving workflow metrics can further improve clinical outcome.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01327989.

Evolving role of endovascular treatment of acute ischemic stroke

The perceived advantages of endovascular treatment for acute ischemic stroke in terms of recanalization, the multimodal and targeted approaches, and perhaps the more permissive rules on devices than on medications for their licensing favored the assumption that endovascular treatment is superior to intravenous thrombolysis for acute treatment of ischemic stroke, and its adoption in more advanced stroke centers. However, this assumption has been questioned by recent clinical trial experience showing that endovascular treatment is not superior to intravenous thrombolysis. The new evidence has changed the perception and the importance of conducting randomized trials in this area. This summary examines the background and outcomes of the latest experience with endovascular techniques in acute stroke treatment based on historical data. The new challenge is how to study the latest generation of devices called stent retrievers, which are faster in recanalizing and easier to use, in selected patients with acute ischemic stroke. In the meantime, the available evidence does not provide support for the use of endovascular treatment of acute ischemic stroke in clinical practice.

[New aspects of stroke medicine]

Systemic thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) remains the only effective and approved medical treatment of acute ischemic stroke. Several studies have demonstrated the importance of rapid recanalization. The efficacy of thrombectomy has so far not been sufficiently shown in randomized clinical trials; therefore, inclusion of suitable patients in one of the currently ongoing randomized trials is of great importance. The early treatment with magnesium after acute ischemic stroke during the pre-hospital phase did not prove to be neuroprotective. Intermittent pneumatic compression of the lower extremities in immobilized stroke patients effectively prevents deep venous thrombosis and pulmonary embolism. In patients with lacunar stroke the combination of aspirin and clopidogrel is not superior to aspirin alone and causes more bleeding complications. The novel oral anticoagulants are superior to warfarin in secondary prevention and carry a lower risk of intracranial and systemic bleeding complications. New studies will investigate whether dabigatran or rivaroxaban are superior to aspirin in secondary prevention after cryptogenic stroke.

Intra-arterial Stroke Management

Acute ischemic stroke is a leading cause of death and the leading cause of disability in the United States. Cerebral neuronal death begins within minutes after threshold values of blood oxygen saturation are crossed. Prompt restoration of oxygenated blood flow into ischemic tissue remains the common goal of reperfusion strategies. This article provides a brief overview of acute ischemic stroke, a summary of the major intra-arterial stroke therapy trials, and comments on current training requirements for the performance of intra-arterial therapies.

Endovascular treatment of acute ischemic stroke

Early recanalization of the occluded artery leads to better clinical outcomes in patients with acute ischemic stroke (AIS) through protection of the time-sensitive penumbra. Intravenous administration of pharmacologic thrombolytic agents has been a standard treatment for AIS. To get better rates of recanalization, enhance the time window, and diminish the possibility of intracranial hemorrhage, endovascular thrombectomy was launched, with first authorization of the Merci clot retriever, a corkscrew-like apparatus, followed by approval of the Penumbra thromboaspiration system. Both devices lead to a high rate of recanalization. On the other hand, time to recanalization was on an average of 45 minutes, with most of the patients attaining only partial recanalization. More lately, retrievable stents have shown promise in decreasing the time to recanalization, and attaining a superior rate of complete clot resolution. The retrievable stent can be released within the clot to engage it within the struts of the stent, and afterwards it is taken back by pulling it under flow arrest. Neurointerventional techniques have a persistently ever-increasing and stimulating role in the management of AIS, as indicated by the advent of several important techniques. Stent retrievers have the capability to be ascertained as the most important approach to endovascular stroke treatment.

Posttreatment variables improve outcome prediction after intra-arterial therapy for acute ischemic stroke

BACKGROUND

There are multiple clinical and radiographic factors that influence outcomes after endovascular reperfusion therapy (ERT) in acute ischemic stroke (AIS). We sought to derive and validate an outcome prediction score for AIS patients undergoing ERT based on readily available pretreatment and posttreatment factors.

METHODS

The derivation cohort included 511 patients with anterior circulation AIS treated with ERT at 10 centers between September 2009 and July 2011. The prospective validation cohort included 223 patients with anterior circulation AIS treated in the North American Solitaire Acute Stroke registry. Multivariable logistic regression identified predictors of good outcome (modified Rankin score ≤2 at 3 months) in the derivation cohort; model β coefficients were used to assign points and calculate a risk score. Discrimination was tested using C statistics with 95% confidence intervals (CIs) in the derivation and validation cohorts. Calibration was assessed using the Hosmer-Lemeshow test and plots of observed to expected outcomes. We assessed the net reclassification improvement for the derived score compared to the Totaled Health Risks in Vascular Events (THRIVE) score. Subgroup analysis in patients with pretreatment Alberta Stroke Program Early CT Score (ASPECTS) and posttreatment final infarct volume measurements was also performed to identify whether these radiographic predictors improved the model compared to simpler models.

RESULTS

Good outcome was noted in 186 (36.4%) and 100 patients (44.8%) in the derivation and validation cohorts, respectively. Combining readily available pretreatment and posttreatment variables, we created a score (acronym: SNARL) based on the following parameters: symptomatic hemorrhage [2 points: none, hemorrhagic infarction (HI)1-2 or parenchymal hematoma (PH) type 1; 0 points: PH2], baseline National Institutes of Health Stroke Scale score (3 points: 0-10; 1 point: 11-20; 0 points: >20), age (2 points: <60 years; 1 point: 60-79 years; 0 points: >79 years), reperfusion (3 points: Thrombolysis In Cerebral Ischemia score 2b or 3) and location of clot (1 point: M2; 0 points: M1 or internal carotid artery). The SNARL score demonstrated good discrimination in the derivation (C statistic 0.79, 95% CI 0.75-0.83) and validation cohorts (C statistic 0.74, 95% CI 0.68-0.81) and was superior to the THRIVE score (derivation cohort: C statistic 0.65, 95% CI 0.60-0.70; validation cohort: C-statistic 0.59, 95% CI 0.52-0.67; p < 0.01 in both cohorts) but was inferior to a score that included age, ASPECTS, reperfusion status and final infarct volume (C statistic 0.86, 95% CI 0.82-0.91; p = 0.04). Compared with the THRIVE score, the SNARL score resulted in a net reclassification improvement of 34.8%.

CONCLUSIONS

Among AIS patients treated with ERT, pretreatment scores such as the THRIVE score provide only fair prognostic information. Inclusion of posttreatment variables such as reperfusion and symptomatic hemorrhage greatly influences outcome and results in improved outcome prediction.

Imaging of acute stroke prior to treatment: current practice and evolving techniques

Standard imaging in acute stroke is undertaken with the aim of diagnosing the underlying cause and excluding stroke mimics. In the presence of ischaemic stroke, imaging is also needed to assess patient suitability for treatment with intravenous thrombolysis. Non-contrast CT is predominantly used, but MRI can also exclude any contraindications to thrombolysis treatment. Advanced stroke imaging such as CT and MR angiography and perfusion imaging are increasingly used in an acute setting. In this review, we discuss the evidence for the application of these advanced techniques in the imaging of acute stroke.

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.

Outcome prediction in acute stroke patients considered for endovascular treatment: a novel tool

Functional outcome following emergent intra-arterial thrombectomy is variable and likely reflects the heterogeneous characteristics of acute stroke patients. The aims of our study were (1) to study which pre-treatment variables correlate with functional outcome and (2) to devise a tool which would reliably predict outcome. Prospective data of patients treated with intra-arterial mechanical thrombectomy in our institution between 2010 and 2012 were collected. A preliminary univariate analysis of baseline variables was performed and data outliers were identified by constructing scatter and box plots. Systematic bivariate analysis was then carried out using a linear regression model and the individual contributing weights of the variables to outcome calculated. The B and constant values from the regression were used to construct a predictive formula. Fifty-seven patients, 35 males (61.4%) and 22 females (38.6%) with a mean age of 62.3 years (range 26-87) were included in the cohort. Statistical correlations of baseline variables and functional outcome showed that age, National Institutes of Health Stroke Scale at presentation and CT leptomeningeal collaterals were strongly correlated (p<0.01), and were later included in the linear regression model. A tool was devised from the regression formula combining weighted inputs of the three variables. Regression statistics and residual analysis were then performed to assess the accuracy and reliability of the proposed tool. The proposed tool is easy to use and reliably predicts functional outcome prior to endovascular therapy. It may help clinical decision-making in the acute setting and offers 'tailor-made' outcome expectations.

Age dependency of safety and outcome of endovascular therapy for acute stroke

Elderly patients generally experience less favorable outcomes and higher mortality after acute stroke than younger patients. The aim of this study was to analyze the influence of age on outcome and safety after endovascular therapy in a large cohort of patients aged between 20 and 90 years. We prospectively acquired data of 1,000 stroke patients treated with endovascular therapy at a single center. Logistic regression analysis was performed to determine predictors of outcome and linear regression analysis to evaluate the association of age and outcome after 3 months. Younger age was an independent predictor of favorable outcome (OR 0.954, p < 0.001) and survival (OR 0.947, p < 0.001) in multivariate regression analysis. There was a linear relationship between age and outcome. Ever increase in 26 years of age was associated with an increase in the modified Rankin Scale of 1 point (p < 0.001). However, increasing age was not a risk factor for symptomatic (p = 0.086) or asymptomatic (p = 0.674) intracerebral hemorrhage and did not influence recanalization success (p = 0.674). Advancing age was associated with a decline of favorable outcomes and survival after endovascular therapy. This decline was linear from age 20 to 90 years, but was not related to lower recanalization rates or higher bleeding risk in the elderly. The efficacy of endovascular stroke therapy seems to be preserved also in the elderly and other factors than efficacy of endovascular therapy such as decreased plasticity are likely to explain the worse outcome with advancing age.

Length of occlusion predicts recanalization and outcome after intravenous thrombolysis in middle cerebral artery stroke

BACKGROUND AND PURPOSE

The length of large vessel occlusion is considered a major factor for therapy in patients with ischemic stroke. We used 4D-CT angiography evaluation of middle cerebral artery occlusion in prediction of recanalization and favorable clinical outcome and after intravenous thrombolysis (IV-tPA).

METHODS

In 80 patients treated with IV-tPA for acute complete middle cerebral artery/M1 occlusion determined using CT angiography and temporal maximum intensity projection, calculated from 4D-CT angiography, the length of middle cerebral artery proximal stump, occlusion in M1 or M1 and M2 segment were measured. Univariate and multivariate analyses were performed to define independent predictors of successful recanalization after 24 hours and favorable outcome after 3 months.

RESULTS

The length of occlusion was measureable in all patients using temporal maximum intensity projection. Recanalization thrombolysis in myocardial infarction 2 to 3 was achieved in 37 individuals (46%). The extension to M2 segment as a category (odds ratio, 4.58; 95% confidence interval, 1.39-15.05; P=0.012) and the length of M1 segment occlusion (odds ratio, 0.82; 95% confidence interval, 0.73-0.92; P=0.0007) with an optimal cutoff value of 12 mm (sensitivity 0.67; specificity 0.71) were significant independent predictors of recanalization. Favorable outcome (modified Rankin scale 0-2) was achieved in 25 patients (31%), baseline National Institutes of Health Stroke Scale (odds ratio, 0.82; 95% confidence interval, 0.72-0.93; P=0.003) and the length of occlusion M1 in segment (odds ratio, 0.79; 95% confidence interval, 0.69-0.91; P=0.0008) with an optimal cutoff value of 11 mm (sensitivity 0.74; specificity 0.76) were significant independent predictors of favorable outcome.

CONCLUSIONS

The length of middle cerebral artery occlusion is an independent predictor of successful IV-tPA treatment.

To do or not to do; dilemma of intra-arterial revascularization in acute ischemic stroke

Background

There has still been lack of evidence for definite imaging criteria of intra-arterial revascularization (IAR). Therefore, IAR selection is left largely to individual clinicians. In this study, we sought to investigate the overall agreement of IAR selection among different stroke clinicians and factors associated with good agreement of IAR selection.

Methods

From the prospectively registered data base of a tertiary hospital, we identified consecutive patients with acute ischemic stroke. IAR selection based on the provided magnetic resonance imaging (MRI) results and clinical information were independently performed by 5 independent stroke physicians currently working at 4 different university hospitals. MRI results were also reviewed by 2 independent experienced neurologists blinded to clinical data and physicians' IAR selection. The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) was calculated on initial DWI and MTT. We arbitrarily used ASPECTS differences between DWI and MTT (D-M ASPECTS) to quantitatively evaluate mismatch.

Results

The overall interobserver agreement of IAR selection was fair (kappa = 0.398). In patients with DWI-ASPECTS >6, interobserver agreement was moderate to substantial (0.398–0.620). In patients with D-M ASPECTS >4, interobserver agreement was moderate to almost perfect (0.532–1.000). Patients with higher DWI or D-M ASPECTS had better agreement of IAR selection.

Conclusion

Our study showed that DWI-ASPSECTS >6 and D-M ASPECTS >4 had moderate to substantial agreement of IAR selection among different stroke physicians. However, there is still poor agreement as to whether IAR should not be performed in patients with lower DWI and D-M ASPECTS.

Management of acute stroke in patients taking novel oral anticoagulants

Each year, 1·0–2·0% of individuals with atrial fibrillation and 0·1–0·2% of those with venous thromboembolism who are receiving one of the novel oral anticoagulants (dabigatran, rivaroxaban, or apixaban) can be expected to experience an acute ischemic stroke. Additionally, 0·2–0·5% of individuals with atrial fibrillation who are receiving one of the novel oral anticoagulants can be expected to experience an intracranial hemorrhage. This opinion piece addresses the current literature and offers practical approaches to the management of patients receiving novel oral anticoagulants who present with an ischemic or hemorrhagic stroke. Specifically, we discuss the role of thrombolysis in anticoagulated patients with acute ischemic stroke and factors to consider concerning restarting anticoagulation after acute ischemic and hemorrhagic stroke.

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.

MRI before intraarterial therapy in ischemic stroke: feasibility, impact, and safety

Intraarterial therapy (IAT) in acute ischemic stroke is effective for opening occlusions of major extracranial or intracranial vessels. Clinical efficacy data are lacking pointing to a need for proper patient selection. We examined feasibility, clinical impact, and safety profile of magnetic resonance imaging (MRI) for patient selection before IAT. In this single-center study, we collected epidemiologic, imaging, and outcome data on all intraarterial-treated patients presenting with anterior circulation occlusions at our center from 2004 to 2011. Magnetic resonance imaging was the first imaging choice. Computer tomography (CT) was performed in the presence of a contraindication. We treated 138 patients. Mean age was 64 years and median National Institutes of Health Stroke Scale (NIHSS) was 17. Major reperfusion (thrombolysis in cerebral infarction (TICI) 2b+3) was achieved in 52% and good outcome defined as modified Rankin Scale (mRS) score 0 to 2 at 90 days was achieved in 41%. Mortality at 90 days was 10%. There was only one symptomatic hemorrhage. Recanalization, age, and stroke severity were associated with outcome. Preprocedure MRI was obtained in 83%. Good outcome was significantly associated with smaller diffusion-weighted imaging (DWI) lesion size at presentation and not with the size of the perfusion lesion. It is feasible to triage patients for IAT using MRI with acceptable rates of poor outcome and symptomatic hemorrhage.

The THRIVE score strongly predicts outcomes in patients treated with the Solitaire device in the SWIFT and STAR trials

BACKGROUND

The Totaled Health Risks in Vascular Events (THRIVE) score strongly predicts clinical outcome, mortality, and risk of thrombolytic haemorrhage in ischemic stroke patients, and performs similarly well in patients receiving intravenous tissue plasminogen activator, endovascular stroke treatment, or no acute treatment. It is not known if the THRIVE score predicts outcomes with the Solitaire endovascular stroke treatment device.

AIMS

To validate the relationship between the THRIVE score and outcomes after treatment with the Solitaire endovascular stroke treatment device.

METHODS

The study conducted a retrospective analysis of the prospective SWIFT and STAR trials to examine the relationship between THRIVE and outcomes after treatment with the Solitaire device. We examined the relationship between THRIVE and clinical outcomes (good outcome or death at 90 days) among patients in SWIFT and STAR. Receiver-operator characteristics curve analysis was used to compare THRIVE score performance with other stroke prediction scores. Multivariable modeling was used to confirm the independence of the THRIVE score from procedure-specific predictors (successful recanalization or device used) and other predictors of functional outcome.

RESULTS

The THRIVE score strongly predicts good outcome and death among patients treated with the Solitaire device in SWIFT and STAR (Mantel-Haenszel chi-square test for trend P < 0·001 for good outcome, P = 0·01 for death). In receiver-operator characteristics (ROC) curve comparisons, totaled health risks in vascular events score is superior to Stroke Prognostication using Age and NIH Stroke Scale score-100 (P < 0·001) and performed similarly to Houston Intra-Arterial Therapy score (HIAT) (P = 0·98) and HIAT-2 (P = 0·54). In multivariable models, THRIVE's prediction of good outcome is not altered after controlling for recanalization or after controlling for device used. The THRIVE score remains a strong independent predictor after controlling for the above predictors together with time to procedure, rate of symptomatic haemorrhage, and use of general anesthesia. Of note, use of general anesthesia was not an independent predictor of outcome in SWIFT + STAR after controlling for totaled health risks in vascular events and other factors.

CONCLUSIONS

The THRIVE score strongly predicts clinical outcome and mortality in patients treated with the Solitaire device in the SWIFT and STAR trials. The lack of interaction between THRIVE and procedure-specific elements such as vessel recanalization or device choice makes the THRIVE score a reasonable candidate for use as a patient selection criterion in stroke clinical trials.

M2 occlusions as targets for endovascular therapy: comprehensive analysis of diffusion/perfusion MRI, angiography, and clinical outcomes

BACKGROUND

The ideal population of patients for endovascular therapy (ET) in acute ischemic stroke remains undefined. Recent ET trials have moved towards selecting patients with proximal middle cerebral artery (MCA) or internal carotid artery occlusions, which will likely leave a gap in our understanding of the treatment outcomes of M2 occlusions.

OBJECTIVE AND METHODS

To examine the presentation, treatment, and outcomes of M2 compared with M1 MCA occlusions in patients undergoing ET by assessing comprehensive MRI, angiography, and clinical data.

RESULTS

We found that M2 occlusions can lead to massive strokes defined by hypoperfused and infarcted volumes as well as death or moderate to severe disability in nearly 50% of patients at discharge. Compared with M1 occlusions, M2 occlusions achieved similar Thrombolysis in Cerebral Infarction (TICI) 2b/3 recanalization rates, with significantly less hemorrhage. M2 occlusions presented with smaller infarct and hypoperfused volumes and had smaller final infarct volumes regardless of recanalization. TICI 2b/3 recanalization of M2 occlusions was associated with smaller infarct volumes compared with TICI 0-2a recanalization, as well as less infarct expansion, in patients who received IV tissue plasminogen activator as well as those that did not. Successful reperfusion of M2 occlusions was associated with improved discharge modified Rankin scale.

CONCLUSIONS

If suitable as targets of ET, M2 occlusions should be given the same consideration as M1 occlusions.

Trapped cerebral thrombectomy device: A case report of a rare complication

Intravenous thrombolysis with recombinant tissue plasminogen activator is currently the standard therapy for acute ischaemic stroke when started within 4.5 h of symptom onset. Systemic thrombolytic therapy can, however, lead to potentially lethal bleeding complications and is contra-indicated in several circumstances. Intra-arterial thrombolysis and/or intra-arterial thrombectomy can overcome these drawbacks and even increase the rate of recanalization. While intravenous thrombolysis is a relatively non-complex treatment, intra-arterial therapy in acute ischaemic stroke patients requires a dedicated intervention team which has to be available at all times. In this case report, we describe the multidisciplinary approach of a rare complication of a trapped mechanical thrombectomy device.

Endovascular treatment for acute ischemic stroke patients: implications and interpretation of IMS III, MR RESCUE, and SYNTHESIS EXPANSION trials: A report from the Working Group of International Congress of Interventional Neurology

OBJECTIVE

The results of Interventional Management of Stroke (IMS) III, Magnetic Resonance and REcanalization of Stroke Clots Using Embolectomy (MR RESCUE), and SYNTHESIS EXPANSION trials are expected to affect the practice of endovascular treatment for acute ischemic stroke. The purpose of this report is to review the components of the designs and methods of these trials and to describe the influence of those components on the interpretation of trial results.

METHODS

A critical review of trial design and conduct of IMS III, MR RESCUE, and SYNTHESIS EXPANSION is performed with emphasis on patient selection, shortcomings in procedural aspects, and methodology of data ascertainment and analysis. The influence of each component is estimated based on published literature including multicenter clinical trials reporting on endovascular treatment for acute ischemic stroke and myocardial infarction.

RESULTS

We critically examined the time interval between symptom onset and treatment and rates of angiographic recanalization to differentiate between "endovascular treatment" and "parameter optimized endovascular treatment" as it relates to the IMS III, MR RESCUE, and SYNTHESIS EXPANSION trials. All the three trials failed to effectively test "parameter optimized endovascular treatment" due to the delay between symptom onset and treatment and less than optimal rates of recanalization. In all the three trials, the magnitude of benefit with endovascular treatment required to reject the null hypothesis was larger than could be expected based on previous studies. The IMS III and SYNTHESIS EXPANSION trials demonstrated that rates of symptomatic intracerebral hemorrhages subsequent to treatment are similar between IV thrombolytics and endovascular treatment in matched acute ischemic stroke patients. The trials also indirectly validated the superiority/equivalence of IV thrombolytics (compared with endovascular treatment) in patients with minor neurological deficits and those without large vessel occlusion on computed tomographic/magnetic resonance angiography.

CONCLUSIONS

The results do not support a large magnitude benefit of endovascular treatment in subjects randomized in all the three trials. The possibility that benefits of a smaller magnitude exist in certain patient populations cannot be excluded. Large magnitude benefits can be expected with implementation of "parameter optimized endovascular treatment" in patients with ischemic stroke who are candidates for IV thrombolytics.

Clinical Outcome after Intra-Arterial Stroke Therapy in the Very Elderly: Why is it so Heterogeneous?

Very elderly patients (i.e., ≥80 years) are disproportionally affected by acute ischemic stroke. They account for a third of hospital stroke admissions, but two-thirds of overall stroke-related morbidity and mortality. There is some evidence of clinical benefit in treating selected very elderly patients with intravenous thrombolysis (IVT). For very elderly patients ineligible or non-responsive to IVT, intra-arterial therapy (IAT) may have promise in improving clinical outcome. However, its unequivocal efficacy in the general population remains to be proven in randomized trials. Small cohort studies reveal that the rate of good clinical outcome for very elderly patients after IAT is highly variable, ranging from 0 to 28%. In addition, they experience higher rates of futile reperfusion than younger patients. Thus, it is imperative to understand the factors that impact on clinical outcome in very elderly patients after IAT. The aim of this review is to examine the factors that may be responsible for the heterogeneous clinical response of the very elderly to IAT. This will allow the reader to integrate the current available evidence to individualize intra-arterial stroke therapy in very elderly patients. Placing emphasis on pre-stroke independent living, smaller infarct core size, short procedure times, and avoiding general anesthesia where feasible, will help improve rates of good clinical outcome.

Time to angiographic reperfusion and clinical outcome after acute ischaemic stroke: an analysis of data from the Interventional Management of Stroke (IMS III) phase 3 trial

BACKGROUND

The IMS III trial did not show a clinical benefit of endovascular treatment compared with intravenous alteplase (recombinant tissue plasminogen activator) alone for moderate or severe ischaemic strokes. Late reperfusion of tissue that was no longer salvageable could be one explanation, as suggested by previous exploratory studies that showed an association between time to reperfusion and good clinical outcome. We sought to validate this association in a preplanned analysis of data from the IMS III trial.

METHODS

We used data for patients with complete proximal arterial occlusions in the anterior circulation who received endovascular treatment and achieved angiographic reperfusion (score on Thrombolysis in Cerebral Infarction scale of grade 2-3) during the endovascular procedure (within 7 h of symptom onset). We used logistic regression to model good clinical outcome (defined as a modified Rankin Scale score of 0-2 at 3 months) as a function of the time to reperfusion. We prespecified variables to be considered for adjustment, including age, baseline National Institutes of Health Stroke Scale score, sex, and baseline blood glucose concentration.

FINDINGS

Of 240 patients who were otherwise eligible for inclusion in our analysis, 182 (76%) achieved angiographic reperfusion. Mean time from symptom onset to reperfusion (ie, procedure end) was 325 min (SD 52). Increased time to reperfusion was associated with a decreased likelihood of good clinical outcome (unadjusted relative risk for every 30-min delay 0·85 [95% CI 0·77-0·94]; adjusted relative risk 0·88 [0·80-0·98]).

INTERPRETATION

Delays in time to angiographic reperfusion lead to a decreased likelihood of good clinical outcome in patients after moderate to severe stroke. Rapid reperfusion could be crucial for the success of future acute endovascular trials.

FUNDING

US National Institutes of Health and National Institute of Neurological Disorders and Stroke.

Acute combined revascularization in acute ischemic stroke with intracranial arterial occlusion: self-expanding solitaire stent during intravenous thrombolysis

PURPOSE

To investigate the safety and efficacy of the self-expanding Solitaire stent used during intravenous thrombolysis (IVT) for intracranial arterial occlusion (IAO) in acute ischemic stroke (AIS).

MATERIALS AND METHODS

Consecutive nonselected patients with AIS with IAO documented on computed tomographic angiography or magnetic resonance angiography and treated with IVT were included in this prospective study. Stent intervention was initiated and performed during administration of IVT without waiting for any clinical or radiologic signs of potential recanalization. Stroke severity was assessed by National Institutes of Health Stroke Scale (NIHSS), and 90-day clinical outcome was assessed by modified Rankin scale (mRS), with a good outcome defined as an mRS score of 0-2. Recanalization was rated by thrombolysis in cerebral infarction (TICI) scale.

RESULTS

Fifty patients (mean age, 66.8 y ± 14.6) had a baseline median NIHSS score of 18.0. Overall recanalization was achieved in 94% of patients, and complete recanalization (ie, TICI 3 flow) was achieved in 72% of patients. The mean time from stroke onset to maximal recanalization was 244.2 minutes ± 87.9, with a median of 232.5 minutes. The average number of device passes was 1.5, with a mean procedure time to maximal recanalization of 49.5 minutes ± 13.0. Symptomatic intracerebral hemorrhage occurred in 6% of patients. The median mRS score at 90 days was 1, and 60% of patients had a good outcome (ie, mRS score 0-2). The overall 3-month mortality rate was 14%.

CONCLUSIONS

Combined revascularization with the Solitaire stent during IVT appears to be safe and effective in the treatment of acute IAO.

Endovascular procedures versus intravenous thrombolysis in stroke with tandem occlusion of the anterior circulation

PURPOSE

Stroke with tandem occlusion within the anterior circulation presents a lower probability of recanalization and good clinical outcome after intravenous (IV) thrombolysis than stroke with single occlusion. The present study describes the impact of endovascular procedures (EPs) compared with IV thrombolysis alone on recanalization and clinical outcome.

MATERIALS AND METHODS

Thirty patients with symptom onset less than 4.5 hours and tandem occlusion within the anterior circulation were analyzed retrospectively. Recanalization was assessed per Thrombolysis In Cerebral Infarction (TICI) classification on computed tomography, magnetic resonance imaging, or digital subtraction angiography within 24 hours. Infarct size was detected on follow-up imaging as a dichotomized variable, ie, more than one third of the territory of the middle cerebral artery. Clinical outcomes were major neurologic improvement, independent outcome (90-d modified Rankin Scale [mRS] score), symptomatic intracerebral hemorrhage (sICH; per European Cooperative Acute Stroke Study criteria), and death within 7 days.

RESULTS

Patients treated with EPs (n = 14) were significantly younger and had a history of arterial hypertension more frequently than patients treated with IV thrombolysis alone (n = 16). Recanalization (ie, TICI score 2b/3; EP, 64%; IV, 19%; P = .01), major neurologic improvement (EP, 64%; IV, 19%; P = .01), and independent outcome (mRS score ≤ 2; EP, 54% IV, 13%; P = .02) occurred more often in the EP group, whereas infarct sizes greater than one third of the MCA territory (EP, 43%; IV, 81%; P = .03) were observed less often. Rates of sICH (P = .12) and death within 7 days (P = .74) did not differ significantly.

CONCLUSIONS

Higher recanalization rate, smaller infarct volume, and better clinical outcome in the EP group should encourage researchers to include this subgroup of patients in prospective randomized trials comparing IV thrombolysis versus EP in stroke.

Thrombolysis in acute ischemic stroke: Experience from a tertiary care centre in India

The management of acute ischemic stroke has undergone a sea of change with the introduction of intravenous thrombolysis (IVT). Current guidelines state that the window period for IVT using rTPA is 4.5 hours. The MERCI, Multi Merci, and Penumbra trials in which patients with acute ischemic stroke were treated using endovascular treatment demonstrated better recanalisation in patients having a large vessel occlusion. However, recently published data from the three large trials IMS 3, Synthesis Expansion, and MR rescue, which compared endovascular treatment with intravenous therapy, failed to demonstrate superiority of endovascular treatment over IVT. In these trials, stent retrievers were used in very few patients. We present our results from a tertiary care center in India where patients are treated using intravenous as well as endovascular modalities. Among the 53 patients with acute ischemic stroke treated between 2010 and 2012, 23 were treated with IVT and 30 with endovascular methods. Stent retriever was used in majority of the endovascular cases.

The effects of citicoline on acute ischemic stroke: a review

Early reopening of the occluded artery is, thus, important in ischemic stroke, and it has been calculated that 2 million neurons die every minute in an ischemic stroke if no effective therapy is given; therefore, "Time is Brain." In massive hemispheric infarction and edema, surgical decompression lowers the risk of death or severe disability defined as a modified Rankin Scale score greater than 4 in selected patients. The majority, around 80%-85% of all ischemic stroke victims, does not fulfill the criteria for revascularization therapy, and also for these patients, there is no effective acute therapy. Also there is no established effective acute treatment of spontaneous intracerebral bleeding. Therefore, an effective therapy applicable to all stroke victims is needed. The neuroprotective drug citicoline has been extensively studied in clinical trials with volunteers and more than 11,000 patients with various neurologic disorders, including acute ischemic stroke (AIS). The conclusion is that citicoline is safe to use and may have a beneficial effect in AIS patients and most beneficial in less severe stroke in older patients not treated with recombinant tissue plasminogen activator. No other neuroprotective agent had any beneficial effect in confirmative clinical trials or had any positive effect in the subgroup analysis. Citicoline is the only drug that in a number of different clinical stroke trials continuously had some neuroprotective benefit.

Revascularization-outcome paradox: not only time and collaterals status, but also complete recanalization contribute to good neurological outcome

The rate of successful recanalization in endovascular trials has not always mirrored the rate of good clinical outcomes, creating a revascularization-outcome paradox. In early experience with the new generation of stent-based thrombectomy devices, 45-77% of patients have achieved good 90-day outcomes despite treatment up to eight-hours after symptom onset. These rates of good functional outcome are clearly higher than those previously reported with other endovascular strategies. We propose that among the factors influencing this difference is the far higher complete recanalization rate and the high ratio of Thrombolysis in Myocardial Infarction 3/Thrombolysis in Myocardial Infarction 2 recanalization obtained with stent retrievers in comparison with previous generation mechanical thrombectomy devices. Recently, we achieved Thrombolysis in Myocardial Infarction 3 in 94% of patients and Thrombolysis in Myocardial Infarction 2 in 6% in a series of patients with acute middle cerebral artery occlusions who were managed with stent-thrombectomy within eight-hours of symptom onset. Good outcomes were achieved in 77%. Extent of recanalization appears to interact with time and collateral supply in determining clinical outcomes.

Setting priorities for stroke care and research

Recent publications describing the sobering global increase in stroke mortality and global life years lost due to stroke despite improvements in developed countries have drawn focus on the severe impact of stroke in the developing world. At the same time, three recent interventional trials that failed to demonstrate an important role for catheter-based therapies in acute stroke have called into question this expensive use of technology. Coupling all of this new data leads to the natural conclusion that a focus on stroke prevention for the developing world, and for the poor in developed countries, should be where we set our priorities for the foreseeable future.

Ischemic posterior circulation stroke: a review of anatomy, clinical presentations, diagnosis, and current management

Posterior circulation strokes represent approximately 20% of all ischemic strokes (1, 2). In contrast to the anterior circulation, several differences in presenting symptoms, clinical evaluation, diagnostic testing, and management strategy exist presenting a challenge to the treating physician. This review will discuss the anatomical, etiological, and clinical classification of PC strokes, identify diagnostic pitfalls, and overview current therapeutic regimens.

Comparison of magnetic resonance imaging mismatch criteria to select patients for endovascular stroke therapy

BACKGROUND AND PURPOSE

The Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 2 (DEFUSE 2) study has shown that clinical response to endovascular reperfusion differs between patients with and without perfusion-diffusion (perfusion-weighted imaging-diffusion-weighted imaging, PWI-DWI) mismatch: patients with mismatch have a favorable clinical response to reperfusion, whereas patients without mismatch do not. This study examined whether alternative mismatch criteria can also differentiate patients according to their response to reperfusion.

METHODS

Patients from the DEFUSE 2 study were categorized according to vessel occlusion on magnetic resonance angiography (MRA) and DWI lesion volume criteria (MRA-DWI mismatch) and symptom severity and DWI criteria (clinical-DWI mismatch). Favorable clinical response was defined as an improvement of ≥8 points on the National Institutes of Health Stroke Scale (NIHSS) by day 30 or an NIHSS score of ≤1 at day 30. We assessed, for each set of criteria, whether the association between reperfusion and favorable clinical response differed according to mismatch status.

RESULTS

A differential response to reperfusion was observed between patients with and without MRA-DWI mismatch defined as an internal carotid artery or M1 occlusion and a DWI lesion<50 mL. Reperfusion was associated with good functional outcome in patients who met these MRA-DWI mismatch criteria (odds ratio [OR], 8.5; 95% confidence interval [CI], 2.3-31.3), whereas no association was observed in patients who did not meet these criteria (OR, 0.5; 95% CI, 0.08-3.1; P for difference between the odds, 0.01). No differential response to reperfusion was observed with other variations of the MRA-DWI or clinical-DWI mismatch criteria.

CONCLUSIONS

The MRA-DWI mismatch is a promising alternative to DEFUSE 2's PWI-DWI mismatch for patient selection in endovascular stroke trials.

Evaluation and management of acute ischemic stroke

PURPOSE OF REVIEW

This review provides an overview of emergent evaluation of the stroke patient with an emphasis on practical issues regarding ischemic stroke treatment.

RECENT FINDINGS

The IV recombinant tissue-type plasminogen activator (rtPA) treatment window has been expanded from 3 to 4.5 hours from symptom onset. The evidence for better outcomes with more rapid initiation of reperfusion therapies is very strong. Adjunctive endovascular therapy has not been shown to benefit all patients with moderate or severe strokes, and investigations are underway to identify subgroups that may benefit from this approach. Endovascular therapy should be considered for patients who are ineligible for IV rtPA and can begin treatment within 6 hours of stroke onset.

SUMMARY

Effective emergent evaluation of a stroke patient requires well-organized systems that maximize speed of assessment and administration of appropriate therapies, including IV rtPA and endovascular therapies.

Increasing Use of Computed Tomographic Perfusion and Computed Tomographic Angiograms in Acute Ischemic Stroke From 2006 to 2010

Background and Purpose—

Our objective was to study nationwide utilization trends of computed tomographic (CT) angiogram (CTA) and CT perfusion (CTP) in acute ischemic stroke and particularly in the context of use of reperfusion therapies.

Methods—

We reviewed the Premier Perspective Database for ischemic stroke–related hospitalizations of adult patients during a 5-year period, 2006 to 2010. Use of multimodal CT-based imaging and reperfusion therapies was determined through the procedure and billing codes. Logistic regression was used to identify predictors of utilization of imaging studies and reperfusion treatments.

Results—

An increasing proportion of ischemic strokes received CTA each year: 3.8% in 2006, 5.6% in 2007, 6.5% in 2008, 7.5% in 2009, and 9.1% in 2010 ( P <0.0001). The proportion of acute strokes that were imaged with CTP imaging also increased each year: 0.05% in 2006, 0.05% in 2007, 0.9% in 2008, 2.2% in 2009, and 2.9% in 2010 ( P <0.0001). Reperfusion treatment was more common among those who were imaged with CTA (13.0%) and CTP (17.6%) compared with those with CT head alone (4.0%; P <0.0001). Specifically, higher rates of recombinant tissue-type plasminogen activator were observed in CTA (10.2%) and CTP (11.4%) compared with those with CT head alone (3.8%; P <0.0001). Similarly, higher rates of mechanical embolectomy were observed in CTA (2.8%) and CTP (6.3%) compared with those with CT head alone (0.2%; P <0.0001).

Conclusions—

There was a marked increase in the rate of CTA and CTP studies in setting of acute ischemic stroke from 2006 to 2010, and both modalities were associated with increased reperfusion therapy use.

Modern medical management of acute ischemic stroke

The modern management of patients with ischemic stroke begins by having a system in place that organizes the provision of preventive, acute treatment, and rehabilitative services. In the acute setting, initial evaluation is aimed at rapidly establishing a diagnosis by excluding stroke mimics, distinguishing between ischemic and hemorrhagic strokes, and determining if the patient is a candidate for treatment with intravenous tissue plasminogen activator (IV-tPA, alteplase). In some centers, select patients who do not qualify for administration of IV-tPA may be considered for endovascular intervention. General measures include the use of platelet antiaggregants, treatment of fever, blood pressure management, and continuation of statins if the patient has already been taking them. Post-acute evaluation and management is aimed at secondary prevention and optimizing recovery, including recognition and treatment of post-stroke depression.

Non-pharmaceutical therapies for stroke: mechanisms and clinical implications

Stroke is deemed a worldwide leading cause of neurological disability and death, however, there is currently no promising pharmacotherapy for acute ischemic stroke aside from intravenous or intra-arterial thrombolysis. Yet because of the narrow therapeutic time window involved, thrombolytic application is very restricted in clinical settings. Accumulating data suggest that non-pharmaceutical therapies for stroke might provide new opportunities for stroke treatment. Here we review recent research progress in the mechanisms and clinical implications of non-pharmaceutical therapies, mainly including neuroprotective approaches such as hypothermia, ischemic/hypoxic conditioning, acupuncture, medical gases and transcranial laser therapy. In addition, we briefly summarize mechanical endovascular recanalization devices and recovery devices for the treatment of the chronic phase of stroke and discuss the relative merits of these devices.