Equipoise among recanalization strategies

New Perspectives in Neuroprotection for Ischemic Stroke

The constant failure of new neuroprotective therapies for ischemic stroke has partially halted the search for new therapies in recent years, mainly because of the high investment risk required to develop a new treatment for a complex pathology, such as stroke, with a narrow intervention window and associated comorbidities. However, owing to recent progress in understanding the stroke pathophysiology, improvement in patient care in stroke units, development of new imaging techniques, search for new biomarkers for early diagnosis, and increasingly widespread use of mechanical recanalization therapies, new opportunities have opened for the study of neuroprotection. This review summarizes the main protective agents currently in use, some of which are already in the clinical evaluation phase. It also includes an analysis of how recanalization therapies, new imaging techniques, and biomarkers have improved their efficacy.

Endovascular Treatment plus Medical Treatment versus Medical Treatment Alone in Ischemic Stroke: A Systematic Review and Meta-Analysis

INTRODUCTION

This study was conducted to assess the hypothesis that endovascular treatment in addition to medical treatment improve stroke mortality and post-stroke disability.

METHODS

In this systematic review and meta-analysis, the studies were included if they were randomized controlled trials in design and compared between endovascular treatment and medical therapy versus medical therapy alone in stroke management.

RESULTS

The search yielded 22 articles that included 5,049 patients. The analysis showed significant association between the intervention and reduction in disability measured by Modified Rankin Scale (mRS) (mRS = 0-2) (odds ratio [OR] = 1.61; 95% confidence intervals [95% CI]: 1.27-2.06) and National Institute of Health Stroke Scale (NIHSS) (NIHSS = 0-15) (OR = 2.13; 95% CI: 1.04-4.34). Also, we found a significant difference in disability scores between the intervention and the medical therapy group (mRS weighted mean difference [WMD] = -0.59; 95% CI: -1.15 to -0.02, NIHSS WMD = -4.52; 95% CI: -6.32 to -2.72). Additionally, there was significant reduction in mortality in the intervention group (OR = 0.79; 95% CI: 0.68-0.92). There was no significant difference in the rate of any serious adverse effects between the two study groups except for asymptomatic intracerebral hemorrhage.

CONCLUSION

Our study provides strong evidence stemmed from randomized clinical trials that endovascular treatment combined with medical therapy is superior to medical therapy alone in the management of stroke.

Adapting to Evolving Technologies and Treatment Guidelines in a Procedural Trial: A Qualitative Review of the CREST-2 Experience

Multiple challenges confront procedural trials, including slow enrollment, lack of equipoise among patients and physicians, and failure to achieve adequate masking. Nonetheless, randomized clinical trials provide the best evidence of efficacy. The evolution of technology, techniques, and standards of care during the conduct of procedural trials challenges external validity. In this study, we review how a multicenter trial of revascularization of asymptomatic carotid arteries for stroke prevention has managed changes in treating carotid stenosis and medical management of atherothrombotic disease. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov number: NCT02089217.

Novel approaches for the delivery of therapeutics in ischemic stroke

Here, we review novel approaches to deliver neuroprotective drugs to salvageable penumbral brain areas of stroke injury with the goals of offsetting ischemic brain injury and enhancing recovery.

Posterior Circulation Occlusions May Be Associated with Distal Emboli During Thrombectomy : Factors for Distal Embolization and a Review of the Literature

Background

Distal embolization or movement of the thrombus to previously uninvolved vasculature are feared complications during stroke thrombectomy. We looked at associated factors in a consecutive series of patients who underwent thrombectomy with the same endovascular device.

Methods

We included all patients with acute ischemic stroke in the anterior or posterior circulation, who underwent thrombectomy with the same thrombectomy device for acute stroke from 2013 to 2016. Distal embolization was defined as any movement of the thrombus into a previously uninvolved portion of the cerebral vasculature or the presence of thrombotic material further downstream in the affected vessel, which occurred after the initial angiogram. We studied patient-related as well as technical factors to determine their association with distal emboli.

Results

In this study 167 consecutive acute stroke patients treated with the emboTrap® device (Cerenovus, Irvine, CA, USA) were included with a median National Institutes of Health Stroke Scale (NIHSS) of 15 (range 2–30) and mean age of 67 years (SD 13.1 years). Of the patients in our cohort 20 (11.9%) experienced distal emboli, with 2.3% into a new territory and 9.6% into a territory distal to the primary occlusion. On univariate analysis, age, intravenous tissue plasminogen activator (tPA), posterior circulation occlusions, and general anesthesia were associated with distal emboli. On multivariate analysis, only posterior circulation occlusions (odds ratio OR 4.506 95% confidence interval CI 1.483–13.692, p = 0.008) were significantly associated with distal emboli. Distal embolization was not significantly associated with worse functional outcomes at 3 months, increased mortality or increased bleeding risk.

Conclusion

Posterior circulation occlusions were significantly associated with distal emboli during thrombectomy, possibly due to the lack of flow arrest during such procedures. New techniques and devices should be developed to protect against embolic complications during posterior circulation stroke thrombectomy.

Effective use of balloon guide catheters in reducing incidence of mechanical thrombectomy related distal embolization

BACKGROUND AND PURPOSE

The clinical benefit of endovascular stroke therapy has been demonstrated in several prospective randomized trials. However, in a relevant percentage of patients, mechanical thrombectomy bears the risk of causing new infarction in initially unaffected vascular territories through thrombus fragmentation and migration of clot debris. The goal of this study was to evaluate the use of the balloon guide catheter (BGC) to effectively achieve flow arrest and thrombus aspiration during the intervention to avoid distal embolization.

METHODS

A retrospective study was performed in 139 patients between October 2010 and May 2016 to analyze occlusions in the middle cerebral artery (MCA) or internal carotid artery (ICA) by using a stent retriever with a BGC (n = 73) or a non-BGC (n = 66). The following data were collected: patient age and gender, along with history of diabetes mellitus, hypertension, atrial fibrillation, smoking, obesity, dyslipidemia, and previous ischemic stroke. Data on procedure time, number of passes, and angiographic findings were also collected. The final reperfusion score was rated based on the Thrombolysis in Cerebral Infarction (TICI) grading scale. Successful recanalization was defined as TICI 3 or 2b.

RESULTS

A total of 139 patients underwent mechanical thrombectomy with the stent retriever. Of the 139 patients, 73 (52.5%) underwent placement of a BGC. The mean age was 65.8 ± 13.5 years, and the median National Institutes of Health Stroke Scale (NIHSS) score was 11. The average initial NIHSS score was lower in the BGC group compared with the non-BGC group (mean, 11.2 ± 5.6 vs. 13.2 ± 5.6; P = 0.03). Patients with BGC had fewer incidences of previous ischemic stroke (12.3% vs. 28.8%; P = 0.01). The numbers of passes were similar between the two groups. The procedure time (99 ± 49.4 min vs. 124 ± 72.2 min; P = 0.02) and the time from onset of symptoms to procedure end (302 ± 102 min vs. 357.2 ± 136.1 min; P = 0.009) were shorter in the BGC group. TICI 3 or 2b recanalization scores were higher in the BGC group compared to the non-BGC group [63/73, 86.3% vs. 48/66, 72.7%; odds ratio (OR), 0.6; 95% confidence interval (CI), 0.2-1.4; P = 0.04]. Importantly, distal embolization was less frequent in the BGC group (5/73, 6.8% vs. 21/66, 31.8%; OR, 6.3; 95% CI, 2.2-18.0; P < 0.001).

CONCLUSIONS

The risk of distal embolization was significantly decreased with the use of a BGC.

Endovascular Therapy of M2 Occlusion in IMS III: Role of M2 Segment Definition and Location on Clinical and Revascularization Outcomes

BACKGROUND AND PURPOSE

Uncertainty persists regarding the safety and efficacy of endovascular therapy of M2 occlusions following IV tPA. We reviewed the impact of revascularization on clinical outcomes in 83 patients with M2 occlusions in the Interventional Management of Stroke III trial according to specific M1-M2 segment anatomic features.

MATERIALS AND METHODS

Perfusion of any M2 branch distinguished M2-versus-M1 occlusion. Prespecified modified TICI and arterial occlusive lesion revascularization and clinical mRS 0-2 end points at 90 days for endovascular therapy-treated M2 occlusions were analyzed. Post hoc analyses of the relationship of outcomes to multiple baseline angiographic M2 and M1 subgroup characteristics were performed.

RESULTS

Of 83 participants with M2 occlusion who underwent endovascular therapy, 41.0% achieved mRS 0-2 at 90 days, including 46.6% with modified TICI 2-3 reperfusion compared with 26.1% with modified TICI 0-1 reperfusion (risk difference, 20.6%; 95% CI, -1.4%-42.5%). mRS 0-2 outcome was associated with reperfusion for M2 trunk (n = 9) or M2 division (n = 42) occlusions, but not for M2 branch occlusions (n = 28). Of participants with trunk and division occlusions, 63.2% with modified TICI 2a and 42.9% with modified TICI 2b reperfusion achieved mRS 0-2 outcomes; mRS 0-2 outcomes for M2 trunk occlusions (33%) did not differ from distal (38.2%) and proximal (26.9%) M1 occlusions.

CONCLUSIONS

mRS 0-2 at 90 days was dependent on reperfusion for M2 trunk but not for M2 branch occlusions. For M2 division occlusions, good outcome with modified TICI 2b reperfusion did not differ from that in modified TICI 2a. M2 segment definition and occlusion location may contribute to differences in revascularization and good outcome between Interventional Management of Stroke III and other endovascular therapy studies.

Randomized controlled trials - a matter of design

Randomized controlled trials (RCTs) are the hallmark of evidence-based medicine and form the basis for translating research data into clinical practice. This review summarizes commonly applied designs and quality indicators of RCTs to provide guidance in interpreting and critically evaluating clinical research data. It further reflects on the principle of equipoise and its practical applicability to clinical science with an emphasis on critical care and neurological research. We performed a review of educational material, review articles, methodological studies, and published clinical trials using the databases MEDLINE, PubMed, and ClinicalTrials.gov. The most relevant recommendations regarding design, conduction, and reporting of RCTs may include the following: 1) clinically relevant end points should be defined a priori, and an unbiased analysis and report of the study results should be warranted, 2) both significant and nonsignificant results should be objectively reported and published, 3) structured study design and performance as indicated in the Consolidated Standards of Reporting Trials statement should be employed as well as registration in a public trial database, 4) potential conflicts of interest and funding sources should be disclaimed in study report or publication, and 5) in the comparison of experimental treatment with standard care, preplanned interim analyses during an ongoing RCT can aid in maintaining clinical equipoise by assessing benefit, harm, or futility, thus allowing decision on continuation or termination of the trial.

What is the Role for Intra-Arterial Therapy in Acute Stroke Intervention?

Intravenous recombinant tissue plasminogen activator continues to be first-line therapy for patients with acute ischemic stroke presenting within the appropriate time window, but one potential limitation is the low rate of recanalization in the setting of large artery occlusions. Intra-arterial (IA) treatment is effective for emergency revascularization of proximal intracranial arterial occlusions, but proof of benefit has been lacking until recently. Our goal is to outline the history of endovascular therapy and review both IA thrombolysis and mechanical interventions. In addition, we will discuss the impact of important trials such as the Third Interventional Management of Stroke (IMS3) trial, and the more recent trials Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN), Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke (ESCAPE), Extending the Time for Thrombolysis in Emergency Neurological Deficits-Intra-Arterial (EXTEND-IA), and Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME) on acute stroke management and the implications for the practicing neurohospitalist.

Preliminary experience with air transfer of patients for rescue endovascular therapy after failure of intravenous tissue plasminogen activator

The present report describes our experience with air transfer of patients with acute ischemic stroke in whom intravenous tissue plasminogen activator (IV t-PA) failed for rescue endovascular therapy (EVT). Twenty-three consecutive patients in whom IV t-PA failed were transferred to our hospital for rescue EVT between February 2011 and April 2013. The amount of time required for transfer, distance, clinical outcomes, and complications were compared between patients transferred by ground (TG group; n = 17) and by air (TA group; n = 6). Computed tomography imaging on arrival revealed hemorrhagic transformation in 1 (5.9%) patient in the TG group, whereas none of the patients in the TA group developed any type of complication. The remaining 22 patients received rescue EVT. The elapsed time from the request call to arrival at our hospital did not significantly differ between the TG and TA groups (45.8 ± 4.9 min vs. 41.6 ± 2.3 min). However, the distance from the primary hospital to our institution was significantly longer for the TA group than for the TG group (38.8 ± 10.4 km vs. 13.5 ± 1.2 km, p = 0.001). The frequency of favorable outcomes (modified Rankin Scale 0-1 at 90 days after onset) in the TG and TA groups were 25.0% and 50.0%, respectively (p = 0.267). Air transfer for patients after IV t-PA failure allowed for more rapid delivery of patients over longer distances than ground transfer.

State-of-the-art endovascular treatment of acute ischemic stroke

Stroke is the third leading cause of death in the USA. An estimated 795,000 new or recurrent stroke events occur annually, mostly ischemic in nature. Arterial recanalization and subsequent reperfusion performed shortly after symptom onset can help to restore brain function in acute ischemic stroke (AIS). The only treatment currently approved by the United States Food and Drug Administration is intravenous tissue plasminogen activator, administered within 4.5 h of symptom onset. However, this short window often precludes effective intervention. Mechanical neurothrombectomy devices offer many potential advantages over pharmacologic thrombolysis, including more rapid achievement of recanalization, enhanced efficacy in treating large-vessel occlusions, and a potentially lower risk of hemorrhagic events. The goal of this chapter is to describe the state-of-the-art neurothrombectomy devices and stenting techniques for endovascular treatment of acute ischemic stroke, as well as to highlight recent advances in reperfusion therapies. Ongoing clinical trials, some with randomized, controlled designs, are included.

Risk of distal embolization with stent retriever thrombectomy and ADAPT

Background

There is a discrepancy in clinical outcomes and the achieved recanalization rates with stent retrievers in the endovascular treatment of ischemic stroke. It is our hypothesis that procedural release of embolic particulate may be one contributor to poor outcomes and is a modifiable risk. The goal of this study is to assess various treatment strategies that reduce the risk of distal emboli.

Methods

Mechanical thrombectomy was simulated in a vascular phantom with collateral circulation. Hard fragment-prone clots (HFC) and soft elastic clots (SECs) were used to generate middle cerebral artery (MCA) occlusions that were retrieved by the Solitaire FR devices through (1) an 8 Fr balloon guide catheter (BGC), (2) a 5 Fr distal access catheter at the proximal aspect of the clot in the MCA (Solumbra), or (3) a 6 Fr guide catheter with the tip at the cervical internal carotid artery (guide catheter, GC). Results from mechanical thrombectomy were compared with those from direct aspiration using the Penumbra 5MAX catheter. The primary endpoint was the size distribution of emboli to the distribution of the middle and anterior cerebral arteries.

Results

Solumbra was the most efficient method for reducing HFC fragments (p<0.05) while BGC was the best method for preventing SEC fragmentation (p<0.05). The risk of forming HFC distal emboli (>1000 µm) was significantly increased using GC. A non-statistically significant benefit of direct aspiration was observed in several subgroups of emboli with size 50–1000 µm. However, compared with the stent-retriever mechanical thrombectomy techniques, direct aspiration significantly increased the risk of SEC fragmentation (<50 µm) by at least twofold.

Conclusions

The risk of distal embolization is affected by the catheterization technique and clot mechanics.

Endovascular revascularization results in IMS III: intracranial ICA and M1 occlusions

BACKGROUND

Interventional Management of Stroke III did not show that combining IV recombinant tissue plasminogen activator (rt-PA) with endovascular therapies (EVTs) is better than IV rt-PA alone.

OBJECTIVE

To report efficacy and safety results for EVT of intracranial internal carotid artery (ICA) and middle cerebral artery trunk (M1) occlusion.

METHODS

Five revascularization methods for persistent occlusions after IV rt-PA treatment were evaluated for prespecified primary and secondary endpoints, after accounting for differences in key baselines variables using propensity scores. Revascularization was scored using the arterial occlusive lesion (AOL) and the modified Thrombolysis in Cerebral Ischemia (mTICI) scores.

RESULTS

EVT of 200 subjects with intracranial ICA or M1 occlusion resulted in 81.5% AOL 2-3 recanalization, in addition to 76% mTICI 2-3 and 42.5% mTICI 2b-3 reperfusion. Adverse events included symptomatic intracranial hemorrhage (SICH) (8.0%), vessel perforations (1.5%), and new emboli (14.9%). EVT techniques used were standard microcatheter n=51; EKOS n=14; Merci n=77; Penumbra n=39; Solitaire n=4; multiple n=15. Good clinical outcome was associated with both TICI 2-3 and TICI 2b-3 reperfusion. Neither modified Rankin scale (mRS) 0-2 (28.5%), nor 90-day mortality (28.5%), nor asymptomatic ICH (36.0%) differed among revascularization methods after propensity score adjustment for subjects with intracranial ICA or M1 occlusion.

CONCLUSIONS

Good clinical outcome was associated with good reperfusion for ICA and M1 occlusion. No significant differences in efficacy or safety among revascularization methods were demonstrated after adjustment. Lack of high-quality reperfusion, adverse events, and prolonged time to treatment contributed to lower-than-expected mRS 0-2 outcomes and study futility compared with IV rt-PA.

TRIAL REGISTRATION NUMBER

NCT00359424.

Determinants of early outcomes in patients with acute ischemic stroke and proximal artery occlusion

BACKGROUND

Proximal artery occlusions (PAO) recanalize in only a small percentage of acute ischemic stroke (AIS) patients treated with intravenous tissue plasminogen activator (IV tPA) alone, yet the benefits of adjunctive or substitutive intra-arterial therapy (IAT) in this patient subgroup are not well established. We evaluated early poststroke outcomes in a cohort of AIS patients with PAO categorized as "likely to benefit" (LTB) from IAT using prespecified criteria.

METHODS

Using a prespecified protocol, 193 patients from our institutional stroke database admitted between January 1, 2007, and December 31, 2011, were prospectively deemed LTB from IAT. Logistic regression was used to determine independent predictors of favorable (discharge to home or acute rehabilitation) versus unfavorable (discharge to skilled nursing facility, hospice, or in-hospital mortality) outcome.

RESULTS

Of the patients included, 29.5% received IV tPA only, 11.4% underwent IAT only, and 37.8% had both. Overall in-hospital mortality was 19.2%. In a univariate analysis, age (odds ratio [OR], .95; 95% confidence interval [CI], .93-.98), IV tPA (OR, 2.3; 95% CI, 1.2-4.3), and history of atrial fibrillation (OR, .5; 95% CI, .28-.97) were associated with outcome. Effect of IAT was not statistically significant (OR, 1.3; 95% CI, .7-2.3; P = .4). In multivariate analysis, the only independent predictor of favorable outcome was IV tPA administration (OR, 2.4; 95% CI, 1.2-5.0). The odds of favorable poststroke outcome were significantly lowered (OR, .3; 95% CI, .1-.6; P = .0006) in those receiving neither IV tPA nor IAT.

CONCLUSIONS

In AIS patients with PAO thought most likely to benefit from IAT, IV tPA independently predicted favorable outcomes. These data reinforce the recommendation to provide early IV tPA to all eligible patients.

Effect of thrombus size on recanalization by bridging intravenous thrombolysis

BACKGROUND AND PURPOSE

Thrombus length has been reported as an important predictor of successful recanalization by intravenous thrombolysis but its influence on bridging thrombolysis has not been investigated yet. The effect of thrombus length on recanalization rates evaluated by catheter angiography early after intravenous bridging thrombolysis was analyzed.

METHODS

Ninety-six consecutive patients with acute cerebral artery occlusion were included. Occlusion site and thrombus length on initial computed tomography angiography or magnetic resonance angiography were related to recanalization after intravenous bridging thrombolysis on the initial series of catheter angiography.

RESULTS

Eleven of 96 patients (11.5%) showed successful recanalization (TICI 2a, 2b or 3) after intravenous bridging thrombolysis. Mean thrombus length in these patients was 10.8 mm as opposed to 15.6 mm in patients without successful recanalization. No thrombus longer than 16 mm showed complete recanalization. Binary logistic regression demonstrated a significant influence of thrombus length on probability of recanalization (odds ratio 0.78, 95% confidence interval 0.65-0.95; P = 0.014).

CONCLUSIONS

Thrombus length is a significant predictor of recanalization rates after bridging thrombolysis. Overall recanalization rate within the time frame until interventional treatment is started was 11.5% after bridging thrombolysis.

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.

The impact of arterial collateralization on outcome after intra-arterial therapy for acute ischemic stroke

BACKGROUND AND PURPOSE

Although intra-arterial therapy for acute ischemic stroke is associated with superior recanalization rates, improved clinical outcomes are inconsistently observed following successful recanalization. There is emerging concern that unfavorable arterial collateralization, though unproven, predetermines poor outcome. We hypothesized that poor leptomeningeal collateralization, assessed by preprocedural CTA, is associated with poor outcome in patients with acute ischemic stroke undergoing intra-arterial therapy.

MATERIALS AND METHODS

We retrospectively analyzed patients with acute ischemic stroke with intracranial ICA and/or MCA occlusions who received intra-arterial therapy. The collaterals were graded on CTA. Univariate and multivariate analyses were used to investigate the association between the dichotomized leptomeningeal collateral score and functional outcomes at 3-months mRS ≤2, mortality, and intracranial hemorrhages.

RESULTS

Eighty-seven patients were included. The median age was 66 years (interquartile range, 54-76 years) and the median NIHSS score at admission was 18 (interquartile range, 14-20). The leptomeningeal collateral score 3 was found to have significant association with the good functional outcome at 3 months: OR = 3.13; 95% CI, 1.25-7.825; P = .016. This association remained significant when adjusted for the use of IV tissue plasminogen activator: alone, OR = 2.998; 95% CI, 1.154-7.786; P = .024; and for IV tissue plasminogen activator and other confounders (age, baseline NIHSS score, and Thrombolysis in Cerebral Infarction grades), OR = 2.985; 95% CI, 1.027-8.673; P = .045.

CONCLUSIONS

We found that poor arterial collateralization, defined as a collateral score of <3, was associated with poor outcome, after adjustment for recanalization success. We recommend that future studies include collateral scores as one of the predictors of functional outcome.

Modern interventional management of stroke

Acute ischemic stroke continues to be one of the leading causes of disability and death and is a financial burden to an already taxed health care system. Much research and investigation has been carried out over the past decade on various recanalization devices aimed at restoring cerebral blood flow. Despite the rapidly improving technical abilities of these devices, it has been difficult to demonstrate corresponding improved clinical outcomes. This article will describe the application of the most recent generation of these devices and briefly discuss the ongoing discrepancy between these technical achievements and stroke outcomes.

Human recombinant glutamate oxaloacetate transaminase 1 (GOT1) supplemented with oxaloacetate induces a protective effect after cerebral ischemia

Blood glutamate scavenging is a novel and attractive protecting strategy to reduce the excitotoxic effect of extracellular glutamate released during ischemic brain injury. Glutamate oxaloacetate transaminase 1 (GOT1) activation by means of oxaloacetate administration has been used to reduce the glutamate concentration in the blood. However, the protective effect of the administration of the recombinant GOT1 (rGOT1) enzyme has not been yet addressed in cerebral ischemia. The aim of this study was to analyze the protective effect of an effective dose of oxaloacetate and the human rGOT1 alone and in combination with a non-effective dose of oxaloacetate in an animal model of ischemic stroke. Sixty rats were subjected to a transient middle cerebral artery occlusion (MCAO). Infarct volumes were assessed by magnetic resonance imaging (MRI) before treatment administration, and 24 h and 7 days after MCAO. Brain glutamate levels were determined by in vivo MR spectroscopy (MRS) during artery occlusion (80 min) and reperfusion (180 min). GOT activity and serum glutamate concentration were analyzed during the occlusion and reperfusion period. Somatosensory test was performed at baseline and 7 days after MCAO. The three treatments tested induced a reduction in serum and brain glutamate levels, resulting in a reduction in infarct volume and sensorimotor deficit. Protective effect of rGOT1 supplemented with oxaloacetate at 7 days persists even when treatment was delayed until at least 2 h after onset of ischemia. In conclusion, our findings indicate that the combination of human rGOT1 with low doses of oxaloacetate seems to be a successful approach for stroke treatment

Hyperthermia in human ischemic and hemorrhagic stroke: similar outcome, different mechanisms

Hyperthermia is a predictor of poor outcome in ischemic (IS) and intracerebral hemorrhagic (ICH) stroke. Our aim was to study the plausible mechanisms involved in the poor outcome associated to hyperthermia in stroke. We conducted a case-control study including patients with IS (n = 100) and ICH (n = 100) within the first 12 hours from symptom onset. Specifically, IS and ICH patients were consecutively included into 2 subgroups, according to the highest body temperature within the first 24 hours: Tmax <37.5°C and Tmax ≥37.5°C, up to reach 50 patients per subgroup of temperature for both IS and ICH patients. Body temperature was determined at admission and every 4 hours during the first 48 hours. Main outcome variable was poor functional outcome (modified Rankin scale score >2) at 3 months. Serum levels of glutamate and active MMP-9 were measured at admission. Our results showed that Tmax ≥37.5°C within the first 24 hours was independently associated with poor outcome in both IS (OR, 12.43; 95% CI, 3.73-41.48; p<0.0001) and ICH (OR, 4.29; 95% CI, 1.32-13.91; p = 0.015) after adjusting for variables with a proven biological relevance for outcome. However, when molecular markers levels were included in the logistic regression model, we observed that glutamate (OR, 1.01; 95% CI, 1.00-1.02; p = 0.001) and infarct volume (OR, 1.06; 95% CI, 1.01-1.10; p = 0.015) were the only variables independently associated to poor outcome in IS, and active MMP-9 (OR, 1.04; 95% CI, 1.00-1.08; p = 0.002) and National Institute of Health Stroke Scale (NIHSS) at admission (OR, 1.29; 95% CI, 1.13-1.49; p<0.0001) in ICH. In conclusion, these results suggest that although the outcome associated to hyperthermia is similar in human IS and ICH, the underlying mechanisms may be different.

The usefulness of the ivy sign on fluid-attenuated intensity recovery images in improved brain hemodynamic changes after superficial temporal artery-middle cerebral artery anastomosis in adult patients with moyamoya disease

Objective

MR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images.

Methods

We enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery.

Results

Ivy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis.

Conclusion

After STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients.

Neurothrombectomy in the treatment of acute ischaemic stroke

Major ischaemic stroke is a leading cause of morbidity and mortality in industrialized countries. For patients with acute stroke, fast and effective vessel recanalization is important for successful treatment. Neurothrombectomy--that is, angiographically performed mechanical thrombus removal from intracranial arteries--results in higher recanalization rates than with pharmaceutical thrombolysis alone, but the value of this treatment in terms of clinical outcome remains to be established. This article summarizes the history of intra-arterial stroke treatment, outlines the recent developments and the different techniques used, and discusses the results of current studies on neurothrombectomy. Owing to the high morphological and clinical variability of stroke, careful patient selection in future randomized controlled trials will be crucial for assessment of the true potential of neurothrombectomy.

Early and continuous neurologic improvements after intravenous thrombolysis are strong predictors of favorable long-term outcomes in acute ischemic stroke

BACKGROUND

Intravenously administered tissue plasminogen activator (IV tPA) remains the only approved therapeutic agent for arterial recanalization in acute ischemic stroke (AIS). Considerable proportion of AIS patients demonstrate changes in their neurologic status within the first 24 hours of intravenous thrombolysis with IV tPA. However, there are little available data on the course of clinical recovery in subacute 2- to 24-hour window and its impact. We evaluated whether neurologic improvement at 2 and 24 hours after IV tPA bolus can predict functional outcomes in AIS patients at 3 months.

METHODS

Data for consecutive AIS patients treated with IV tPA within 4.5 hours of symptom onset during 2007-2011 were prospectively entered in our thrombolyzed registry. National Institutes of Health Stroke Scale (NIHSS) scores were recorded before IV tPA bolus, at 2 and 24 hours. Early neurologic improvement (ENI) at 2 hours was defined as a reduction in NIHSS score by 10 or more points from baseline or an absolute score of 4 or less points at 2 hours. Continuous neurologic improvement (CNI) was defined as a reduction of NIHSS score by 8 or more points between 2 and 24 hours or an absolute score of 4 or less points at 24 hours. Favorable functional outcomes at 3 months were determined by modified Rankin Scale (mRS) score of 0-1.

RESULTS

Of 2460 AIS patients admitted during the study period, 263 (10.7%) received IV tPA within the time window; median age was 64 years (range 19-92), with 63.9% being men, a median NIHSS score of 17 points (range 5-35), and a median onset-to-treatment time of 145 minutes (range 57-270). Overall, 130 (49.4%) thrombolyzed patients achieved an mRS score of 0-1 at 3 months. The female gender, age, and baseline NIHSS score were found to be significantly associated with CNI on univariate analysis. On multivariate analysis, NIHSS score at onset and female gender (odds ratio [OR]: 2.218, 95% confidence interval [CI]: 1.140-4.285; P=.024) were found to be independent predictors of CNI. Factors associated with favorable outcomes at 3 months on univariate analysis were younger age, female gender, hypertension, NIHSS score at onset, recanalization on transcranial Doppler (TCD) monitoring or repeat computed tomography (CT) angiography, ENI at 2 hours, and CNI. On multivariate analysis, NIHSS score at onset (OR per 1-point increase: .835, 95% CI: .751-.929, P<.001), 2-hour TCD recanalization (OR: 3.048, 95% CI: 1.537-6.046; P=.001), 24-hour CT angiographic recanalization (OR: 4.329, 95% CI: 2.382-9.974; P=.001), ENI at 2 hours (OR: 2.536, 95% CI: 1.321-5.102; P=.004), and CNI (OR: 7.253, 95% CI: 3.682-15.115; P<.001) were independent predictors of favorable outcomes at 3 months.

CONCLUSIONS

Women are twice as likely to have CNI from the 2- to 24-hour period after IV tPA. ENI and CNI within the first 24 hours are strong predictors of favorable functional outcomes in thrombolyzed AIS patients.

Developments on the horizon in the treatment of neurovascular problems

The field of Interventional Neuroradiology and Endovascular Neurosurgery has seen much technical advancement in the past two decades, which has brought the specialty from its infancy as an alternative therapy to the current standing as near standard of care for many complex neurovascular pathologies. This past year is no exception with flow diverting stents and stent retriever devices aiming to make their mark on advanced treatments for intracranial aneurysms and ischemic stroke, respectively. This review article will focus on the development of these technologies, current data supporting their advantages and limitations, and a brief expert opinion on where these technologies may take the field in the next few years.

Endovascular therapy after intravenous t-PA versus t-PA alone for stroke

BACKGROUND

Endovascular therapy is increasingly used after the administration of intravenous tissue plasminogen activator (t-PA) for patients with moderate-to-severe acute ischemic stroke, but whether a combined approach is more effective than intravenous t-PA alone is uncertain.

METHODS

We randomly assigned eligible patients who had received intravenous t-PA within 3 hours after symptom onset to receive additional endovascular therapy or intravenous t-PA alone, in a 2:1 ratio. The primary outcome measure was a modified Rankin scale score of 2 or less (indicating functional independence) at 90 days (scores range from 0 to 6, with higher scores indicating greater disability).

RESULTS

The study was stopped early because of futility after 656 participants had undergone randomization (434 patients to endovascular therapy and 222 to intravenous t-PA alone). The proportion of participants with a modified Rankin score of 2 or less at 90 days did not differ significantly according to treatment (40.8% with endovascular therapy and 38.7% with intravenous t-PA; absolute adjusted difference, 1.5 percentage points; 95% confidence interval [CI], -6.1 to 9.1, with adjustment for the National Institutes of Health Stroke Scale [NIHSS] score [8-19, indicating moderately severe stroke, or ≥20, indicating severe stroke]), nor were there significant differences for the predefined subgroups of patients with an NIHSS score of 20 or higher (6.8 percentage points; 95% CI, -4.4 to 18.1) and those with a score of 19 or lower (-1.0 percentage point; 95% CI, -10.8 to 8.8). Findings in the endovascular-therapy and intravenous t-PA groups were similar for mortality at 90 days (19.1% and 21.6%, respectively; P=0.52) and the proportion of patients with symptomatic intracerebral hemorrhage within 30 hours after initiation of t-PA (6.2% and 5.9%, respectively; P=0.83).

CONCLUSIONS

The trial showed similar safety outcomes and no significant difference in functional independence with endovascular therapy after intravenous t-PA, as compared with intravenous t-PA alone. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00359424.).

The 2010 British Association of Stroke Physicians Survey of interventional treatments for stroke in the United Kingdom

INTRODUCTION

The UK National Stroke Strategy (Department of Health 2007) states that patients should have access to a stroke service with neurointerventional capacity. This survey was conducted by the Clinical Standards Committee of the British Association of Stroke Physicians to get a snapshot of the availability of interventional treatments for stroke in the United Kingdom.

METHODS

Questionnaires covering availability of endovascular treatments for stroke, e.g. intra-arterial thrombolysis and mechanical thrombectomy, were emailed to all British Association of Stroke Physicians members in October 2010. Where more than one response was received from the same hospital, the data were only entered once. If there was a discrepancy between different respondents for the same hospital, details were cross-checked with the respondents to ensure accuracy.

RESULTS

Responses were received from 58 hospitals in England, Scotland, Wales, and Northern Ireland. Intra-arterial thrombolysis and/or mechanical thrombectomy were available in 23 hospitals. Of these, three had not performed any procedures in 2010. Twenty centres had conducted a mean (range) of eight (2-20) procedures during the 10-month period. Thirty-five hospitals were not offering endovascular treatments. Sixteen of these were not referring patients to centres which could provide interventional treatments. Hospitals offering endovascular treatments had a mean (range) of 5.2 (2-12) stroke physicians, 2.3 (0-4) interventional neuroradiologists, and 3.6 (0-9) noninterventional neuroradiologists. Only two hospitals providing interventions had four or more interventional neuroradiologists.

CONCLUSIONS

Only a small number of hospitals in the United Kingdom provide interventional treatments for stroke. Almost 50% of hospitals not providing interventions had no processes in place for referral to providers.

Fingolimod reduces hemorrhagic transformation associated with delayed tissue plasminogen activator treatment in a mouse thromboembolic model

BACKGROUND AND PURPOSE

The sphingosine 1-phosphate receptor agonist fingolimod reduces infarct size in rodent models of stroke and enhances blood-brain barrier integrity. Based on these observations, we hypothesized that combination of fingolimod with tissue plasminogen activator (tPA) would reduce the risk of hemorrhagic transformation associated with delayed administration of tPA.

METHODS

We evaluated the effects of fingolimod in a mouse model of thromboembolic stroke, in which both the beneficial effect of reperfusion associated with early tPA treatment and hemorrhagic transformation associated with delayed administration mimic clinical observations in humans.

RESULTS

Our results demonstrate that fingolimod treatment attenuates the neurological deficit and reduces infarct volume after in situ thromboembolic occlusion of the middle cerebral artery. Combination of fingolimod and tPA improves the neurological outcome of the thrombolytic therapy and reduces the risk of hemorrhagic transformation associated with delayed administration of tPA.

CONCLUSIONS

This study confirms the protective efficacy of fingolimod as a treatment against ischemic stroke in another rodent model of stroke (thromboembolic occlusion), and suggests that fingolimod could potentially be used in combination with tPA to reduce the risk of brain hemorrhage.

Clinical trial design for endovascular ischemic stroke intervention

BACKGROUND

Randomized, double-blinded, placebo-controlled trials have significant impact on clinical practice. The ultimate goal of a clinical trial of therapy for acute ischemic stroke (AIS) is to compare 2 interventions. Challenges may include interventional therapy standardization, enrollment rate, patient selection, biases, data and safety monitoring, reporting, and financial and logistical support.

METHOD

Selected randomized and single-arm prospective AIS trial designs. Clinical trial elements and their challenges are reviewed. Innovative designs and proposed recommendations to overcome some of the specific challenges and limitations are discussed.

RESULTS

AIS therapy trials have specific challenges related to ethical issues, enrollment rate, outcome measures, limited time to treatment, efficacy, safety, and limited or variable operator experience with complex technology in a delicate end organ. Proposed suggestions for improving trial design include the following: incorporation of a lead-in phase; careful patient and outcome measure selection; historical, concurrent, or hybrid controls; open data access; and a Bayesian approach. An open data paradigm may facilitate creation of computerized prediction models for future trials (minimizing cost by decreasing sample size or providing futility analyses and directing resources to other trials). Collaborative, consortium, and network infrastructures may allow more effective and efficient study completion. Self-learning, self-correcting trials with intrinsic flexibility to adapt may help future clinical trial design in AIS.

CONCLUSION

The randomized clinical trial design in AIS endovascular therapy is challenging. Lead-in phases, careful patient selection, use of innovative outcome measures, control groups, and newer clinical trial design may enhance conduct of future trials, their validity, and their results.

Is intra-arterial thrombolysis beneficial for M2 occlusions? Subgroup analysis of the PROACT-II trial

BACKGROUND AND PURPOSE

The role of endovascular therapy for acute M2 trunk occlusions is debatable. Through a subgroup analysis of Prolyse in Acute Cerebral Thromboembolism-II, we compared outcomes of M2 occlusions in treatment and control arms.

METHODS

Solitary M2 occlusions were identified from the Prolyse in Acute Cerebral Thromboembolism-II database. Primary endpoints were successful angiographic reperfusion (TICI 2-3) at 120 minutes and functional independence (mRS 0-2) at 90 days.

RESULTS

Forty-four patients with solitary M2 occlusions, 30 in the treatment arm and 14 in the control arm, were identified. Successful reperfusion (TICI 2-3) was achieved in 53.6% and 16.7% of patients in the treatment and control arms, respectively (P=0.04). A favorable clinical outcome (mRS 0-2) was observed in 53.3% and 28.6%, respectively (P=0.19). Baseline characteristics were similar between the 2 groups.

CONCLUSIONS

Intra-arterial thrombolysis may lead to a 3-fold increase in the rate of early reperfusion of solitary M2 occlusions and could potentially double the chance of a favorable functional outcome at 90 days. Clinical Trial Registration- This trial was not registered because enrollment began before July 1, 2005.

Antegrade flow across incomplete vessel occlusions can be distinguished from retrograde collateral flow using 4-dimensional computed tomographic angiography

BACKGROUND AND PURPOSE

In acute stroke patients with intracranial vessel occlusion, angiographic demonstration of antegrade contrast opacification distal to the occlusion site (termed the "clot outline sign") has been associated with higher rates of vessel recanalization. We sought to determine whether antegrade flow can be demonstrated on time-resolved 4-dimensional computed tomographic angiography (4-dimensional CTA), whether it can be distinguished from retrograde collateral flow, and if it can be used to predict early recanalization.

METHODS

Fifty-seven acute stroke patients with intracranial anterior circulation vessel occlusion were retrospectively identified. All patients had received a multimodal computed tomography examination including thin-section 4-dimensional CTA and subsequent digital subtraction angiography as part of an endovascular procedure. Pretreatment 4-dimensional CTA and single-phase CTA were assessed for presence of antegrade contrast opacification distal to the occlusion site. Digital subtraction angiograms were reviewed for preintervention Thrombolysis in Cerebral Infarction grade, presence of the clot outline sign, as well as postintervention Thrombolysis in Cerebral Infarction grade.

RESULTS

On 4-dimensional CTA, evidence of antegrade flow was present in 11 of 57 cases (19.3%). Compared with angiography, 4-dimensional CTA predicted antegrade flow with 100% sensitivity and 97.9% specificity. Single-phase CTA offered 40% sensitivity and 87.2% specificity. Early recanalization occurred in 3 patients (6.5%) after intravenous thrombolysis (n=46); all demonstrated antegrade flow on 4-dimensional CTA.

CONCLUSIONS

Using 4-dimensional CTA, it is possible to noninvasively distinguish antegrade flow across a cerebral artery occlusion from retrograde collateral flow. Presence of antegrade flow on 4-dimensional CTA is associated with an increased chance of early vessel recanalization.

Glutamate excitoxicity is the key molecular mechanism which is influenced by body temperature during the acute phase of brain stroke

Glutamate excitotoxicity, metabolic rate and inflammatory response have been associated to the deleterious effects of temperature during the acute phase of stroke. So far, the association of temperature with these mechanisms has been studied individually. However, the simultaneous study of the influence of temperature on these mechanisms is necessary to clarify their contributions to temperature-mediated ischemic damage. We used non-invasive Magnetic Resonance Spectroscopy to simultaneously measure temperature, glutamate excitotoxicity and metabolic rate in the brain in animal models of ischemia. The immune response to ischemia was measured through molecular serum markers in peripheral blood. We submitted groups of animals to different experimental conditions (hypothermia at 33°C, normothermia at 37°C and hyperthermia at 39°C), and combined these conditions with pharmacological modulation of glutamate levels in the brain through systemic injections of glutamate and oxaloacetate. We show that pharmacological modulation of glutamate levels can neutralize the deleterious effects of hyperthermia and the beneficial effects of hypothermia, however the analysis of the inflammatory response and metabolic rate, demonstrated that their effects on ischemic damage are less critical than glutamate excitotoxity. We conclude that glutamate excitotoxicity is the key molecular mechanism which is influenced by body temperature during the acute phase of brain stroke.

Systematic review of outcome after ischemic stroke due to anterior circulation occlusion treated with intravenous, intra-arterial, or combined intravenous+intra-arterial thrombolysis

BACKGROUND AND PURPOSE

The optimal approach to recanalization in acute ischemic stroke is unknown. We performed a literature review and meta-analysis comparing the relative efficacy of 6 reperfusion strategies: (1) 0.9 mg/kg intravenous tissue-type plasminogen activator; (2) intra-arterial chemical thrombolysis; (3) intra-arterial mechanical thrombolysis; (4) intra-arterial combined chemical/mechanical thrombolysis; (5) 0.6 mg/kg intravenous tissue-type plasminogen activator and intra-arterial thrombolysis; and (6) 0.9 mg/kg intravenous tissue-type plasminogen activator and intra-arterial thrombolysis.

METHODS

A literature search in Medline, Embase, and the Cochrane database identified case series, observational studies, and treatment arms of randomized trials of anterior circulation arterial occlusion treated with thrombolytic therapy. Included studies had ≥10 subjects, mean time to treatment <6 hours, and treatment specific reporting of disability, death, and intracerebral hemorrhage. Multivariable metaregression evaluated the effects of treatment group on outcome at the same time as accounting for differences in baseline covariates.

RESULTS

A total of 2986 abstracts were identified from which 54 studies (5019 subjects) were included. There were significant differences across groups in age (P=0.0008), baseline National Institutes of Health Stroke Scale (P=0.0002), and time to treatment initiation (P<0.0001). There were also differences in mean modified Rankin Scale (P<0.0001), mortality (P=0.0024), and symptomatic intracerebral hemorrhage (P=0.0305). Differences in modified Rankin Scale were not significant in the metaregression and likely attributable to differences in baseline covariates between studies.

CONCLUSIONS

This study found no evidence that one reperfusion strategy is superior with respect to efficacy or safety, supporting clinical equipoise between reperfusion strategies. Intravenous tissue-type plasminogen activator remains the standard of care for acute ischemic stroke. Randomized clinical trials are necessary to determine the efficacy of alternative reperfusion strategies. Participation in such trials is strongly recommended.

Outcome of MRI-based intravenous thrombolysis in carotid-T occlusion

Low recanalization rates and poor clinical outcome have been reported after intravenous thrombolysis (IV-tPA) in carotid-T occlusion (CTO). We studied clinical outcome and imaging findings of MRI-based intravenous thrombolysis in CTO. Data of patients with acute ischemic stroke and CTO treated with IV-tPA within 6 h of symptom onset based on MRI criteria were retrospectively analyzed. Vessel occlusion was defined based on MR angiography. Acute diffusion and perfusion lesion volumes and final infarct volumes after 3-7 days were delineated. The National Institutes of Health Stroke Scale (NIHSS) was used to assess the neurological deficit on admission. Recanalization was evaluated after 24 h. Clinical outcome was assessed using the modified Rankin Scale (mRS) after 90 days. Clinical and imaging data were compared to patients with middle cerebral artery main stem occlusion (MCAO). A total of 20 patients with CTO and 51 patients with MCAO were studied. Onset to treatment time, NIHSS on admission, initial diffusion and perfusion lesion volumes, and recanalization rates after 24 h were similar between groups. Final infarct volume was larger for CTO (82 vs. 30 ml, p = 0.006). Although overall outcome was not significantly different between groups (p = 0.251), independent outcome (mRS 0-2) tended to be less frequent in CTO (17 vs. 39 %), while poor outcome (mRS 4-6) appeared more common (72 vs. 43 %). The proportion of patients with good clinical outcome after intravenous thrombolysis in CTO is small. Moreover, final infarct volume is larger and clinical outcome appears to be worse compared to MCAO.

Neuroprotection or increased brain damage mediated by temperature in stroke is time dependent

The control of temperature during the acute phase of stroke may be a new therapeutic target that can be applied in all stroke patients, however therapeutic window or timecourse of the temperature effect is not well established. Our aim is to study the association between changes in body temperature in the first 72 hours and outcome in patients with ischemic (IS) and hemorrhagic (ICH) stroke. We prospectively studied 2931 consecutive patients (2468 with IS and 463 with ICH). Temperature was obtained at admission, and at 24, 48 and 72 hours after admission. Temperature was categorized as low (<36°C), normal (36–37°C) and high (>37°C). As the main variable, we studied functional outcome at 3 months determined by modified Rankin Scale.

Temperature in stroke patients is higher than in controls, and increases gradually in the first 72 hours after stroke. A positive correlation between temperature and stroke severity determined by NIHSS was found at 24 and 48 hours, but not at admission or 72 hours. In a logistic regression model, high temperature was associated with poor outcome at 24 hours (OR 2.05, 95% CI 1.59–2.64, p<0.0001) and 48 hours (OR 1.93, 95% CI 1.08–2.34, p = 0.007), but not at admission or 72 hours.

Temperature increases in patients with stroke in the first 72 hours, with the harmful effect of high temperature occurring in the first 48 hours. The neuroprotective effect of low temperature occurs within the first 24 hours from stroke onset.

Acute ischemic stroke in the setting of cervical carotid occlusion: a proposed management strategy

BACKGROUND

Occlusion of the extracranial internal carotid artery, whether a result of atherothrombosis or dissection, is a challenging cause of ischemic stroke, characterized by a dismal natural history and a poor response to systemic thrombolysis.

METHODS

Review of the literature and proposal of a management strategy.

RESULTS

In most patients, symptoms are caused by a coexistent intracranial occlusion, and treatment of the latter dictates the final outcome. However, a smaller subset of patients present with acute cerebral hemodynamic insufficiency requiring recanalization of the extracranial vessel. Careful analysis of the initial angiograms, particularly the extent and pattern of collateral flow, will usually give the clue as to the mechanism of stroke. The distal lesion can often be accessed by advancing a microcatheter, either through collateral channels or through the proximal occlusion itself.

CONCLUSIONS

In all cases, the importance of prompt and timely recanalization through aggressive intra-arterial therapy cannot be overemphasized.

Two-hour improvement of patients in the National Institute of Neurological Disorders and Stroke trials and prediction of final outcome

BACKGROUND AND PURPOSE

Ongoing clinical trials are using early response to intravenous tissue-type plasminogen activator (tPA) to stratify patients into endovascular therapies. Little is known about the likelihood of early recovery and its correlation with final stroke outcome.

METHODS

We analyzed the National Institute of Neurological Disorders and Stroke tPA dataset for patients with early improvement (EI), a change of ≥4, or score 0 on the 2-hour National Institutes of Health Stroke Scale (NIHSS) to predict good 90-day outcome. We adjusted for multiple confounders and divided the patients by baseline NIHSS score 0 to 10, 11 to 20, >20, and stroke type to analyze if EI predicted good outcome across stroke severities and types. We analyzed different EI thresholds to identify the best level of NIHSS change to predict good 90-day outcome using a receiver-operator characteristic curve.

RESULTS

In total, 183 of 624 (29.3%) patients had EI, 112 of 312 (35.9%) in the tPA group had EI, and 71 of 312 (22.7%) in the placebo group had EI (P<0.0001). Smokers (P=0.012) and patients treated in <90 minutes (P=0.008) were more likely to have EI; diabetic patients (P=0.023) were less likely to show EI. The baseline NIHSS (mean±SD) of patients with EI was 16.1±6.5 versus 14.3±7.4 (P=0.001). A 90-day modified Rankin Scale score of 0 to 1 was achieved in 68 of 112 (60.7%) tPA-treated patient with EI and 65 of 200 (32.5%) without (placebo groups 30 of 71 [42.3%] versus 53/241 [22.0%]). The adjusted odds ratio for good outcome was 1.71 (95% confidence interval [CI], 1.1-2.6; P=0.011) for tPA treatment and 7.69 (95% CI, 4.63-12.76; P<0.0001) for early improvement. EI predicted good outcome in patients with cardioembolic (13.6; 95% CI, 3.6-51.5) and small vessel (6.98; 95% CI, 2.86-17.03), but not large vessel stroke (1.82; 95% CI, 0.38-8.59). The receiver-operator characteristic curve showed that a threshold of 4 on the NIHSS for prediction of good outcome had a sensitivity of 84% and 36% specificity.

CONCLUSIONS

Early improvement was more common in tPA-treated patients and was associated with good 90-day outcome. Whereas 32.5% of nonresponders after tPA had a good 90-day outcome, the use of EI to predict stroke outcome shows value.

Partial Aortic Occlusion for Cerebral Perfusion Augmentation

Background and Purpose—

Fewer than 5% of patients with acute ischemic stroke are currently treated, and there is need for additional treatment options. A novel catheter treatment (NeuroFlo) that increases cerebral blood flow was tested to 14 hours.

Methods—

The Safety and Efficacy of NeuroFlo in Acute Ischemic Stroke trial is a randomized trial of the safety and efficacy of NeuroFlo treatment in improving neurological outcome versus standard medical management. The primary safety end point was the incidence of serious adverse events through 90 days. The primary efficacy end point on a modified intent-to-treat population was a global disability end point at 90 days. Secondary end points included mortality, intracranial hemorrhage, modified Rankin scale score outcome of 0 to 2, and modified Rankin scale shift analysis.

Results—

Between October 2005 and January 2010, 515 patients were enrolled at 68 centers in 9 countries. The primary efficacy end point did not reach statistical significance (OR, 1.17; CI, 0.81–1.67; P =0.407). The primary safety end point did not show a difference in serious adverse events ( P =0.923). Ninety-day mortality was 11.3% (26/230) in treatment and 16.3% (42/257) in control ( P =0.087). Post hoc analyses showed that patients presenting within 5 hours (OR, 3.33; CI, 1.31–8.48), with NIHSS score 8 to 14 (OR, 1.80; CI, 0.99–3.30), or older than age 70 years (OR, 2.02; CI, 1.02–4.03) had better modified Rankin scale score outcomes of 0 to 2; additionally, there were fewer stroke-related deaths in treatment compared to control groups (7.4%=17/230; 14.4%=37/257).

Conclusions—

The trial met its primary safety end point but not its primary efficacy end point. Signals of treatment effect were suggested on all-cause mortality, in patients presenting early, older than age 70 years, or with moderate strokes, but these require confirmation.

Clinical Trial Registration Information—

URL: http://clinicaltrials.gov . Unique identifier: NCT00119717.

Recanalization and reperfusion in acute ischemic stroke

Revascularization remains the most intuitive strategy to reverse ischemic injury associated with arterial occlusion in acute stroke. Revascularization may lead to opening of an occluded artery, or recanalization, yet restoration of downstream flow, or reperfusion, may not ensue. Revascularization strategies and novel devices continue to broaden options for the treatment of acute stroke, but it is increasingly apparent that selection criteria to identify ideal cases are needed to refine triage and minimize adverse events. The results of recent work on reperfusion may rapidly alter routine clinical practice for evolving ischemia in the brain.

Low rates of acute recanalization with intravenous recombinant tissue plasminogen activator in ischemic stroke: real-world experience and a call for action

BACKGROUND AND PURPOSE

Acute rates of recanalization after intravenous (IV) recombinant tissue plasminogen activator (rt-PA) in proximal vessel occlusion have been estimated sparingly, typically using transcranial Doppler (TCD). We aimed to study acute recanalization rates of IV rt-PA in CT angiogram-proven proximal (internal carotid artery [ICA], M1 middle cerebral artery [MCA], M2-MCA, and basilar artery) occlusions and their effects on outcome.

MATERIALS AND METHODS

The CT angiogram database of the Calgary stroke program was reviewed for the period 2002 to 2009. All patients with proximal vessel occlusions receiving IV rt-PA who were assessed for recanalization by TCD or angiogram (for acute endovascular treatment) were included for analysis. Rates of acute recanalization as observed on TCD/first run of angiogram and postendovascular therapy recanalization rates were noted. Modified Rankin Scale score ≤2 at 3 months was used as a good outcome.

RESULTS

Among 1341 patients in the CT angiogram database, 388 patients with proximal occlusion were identified. Of these, 216 patients had received IV rt-PA; 127 patients underwent further imaging to assess recanalization. Among the patients undergoing TCD (n=46) and cerebral angiogram (n=103), only 27 (21.25%) patients had acute recanalization. By occlusion subtype, the rates of recanalization were: distal ICA (with or without ICA neck occlusion or stenotic disease) 1 of 24 (4.4%); M1-MCA (with or without ICA neck occlusion or stenotic disease) 21 of 65 (32.3%); M2-MCA 4 of 13 (30.8%); and basilar artery 1 of 25 (4%). Onset to rt-PA time was comparable in patients with and without recanalization. Recanalization (P<0.0001; risk ratio, 2.7; 95% confidence interval, 1.5-4.6) was the strongest predictor of outcome (adjusted for age and National Institutes of Health Stroke Scale score).

CONCLUSIONS

A low rate of acute recanalization was observed with IV rt-PA in proximal vessel occlusions identified by baseline CT angiogram. Recanalization was the strongest predictor of good outcome.