Urgent therapy for stroke. Part I. Pilot study of tissue plasminogen activator administered within 90 minutes

Stroke outcomes are worse with larger leukoaraiosis volumes

Leukoaraiosis or white matter hyperintensities are frequently observed on magnetic resonance imaging of stroke patients. We investigated how white matter hyperintensity volumes affect stroke outcomes, generally and by subtype. In total, 5035 acute ischaemic stroke patients were enrolled. Strokes were classified as large artery atherosclerosis, small vessel occlusion, or cardioembolism. White matter hyperintensity volumes were stratified into quintiles. Mean age (± standard deviation) was 66.3 ± 12.8, 59.6% male. Median (interquartile range) modified Rankin Scale score was 2 (1-3) at discharge and 1 (0-3) at 3 months; 16.5% experienced early neurological deterioration, and 3.3% recurrent stroke. The Cochran-Mantel-Haenszel test with adjustment for age, stroke severity, sex, and thrombolysis status showed that the distributions of 3-month modified Rankin Scale scores differed across white matter hyperintensity quintiles (P < 0.001). Multiple ordinal logistic regression analysis showed that higher white matter hyperintensity quintiles were independently associated with worse 3-month modified Rankin Scale scores; adjusted odds ratios (95% confidence interval) for the second to fifth quintiles versus the first quintile were 1.29 (1.10-1.52), 1.40 (1.18-1.66), 1.69 (1.42-2.02) and 2.03 (1.69-2.43), respectively. For large artery atherosclerosis (39.0%), outcomes varied by white matter hyperintensity volume (P = 0.01, Cochran-Mantel-Haenszel test), and the upper three white matter hyperintensity quintiles (versus the first quintile) had worse 3-month modified Rankin Scale scores; adjusted odds ratios were 1.45 (1.10-1.90), 1.86 (1.41-2.47), and 1.89 (1.41-2.54), respectively. Patients with large artery atherosclerosis were vulnerable to early neurological deterioration (19.4%), and the top two white matter hyperintensity quintiles were more vulnerable still: 23.5% and 22.3%. Moreover, higher white matter hyperintensities were associated with poor modified Rankin Scale improvement: adjusted odds ratios for the upper two quintiles versus the first quintile were 0.66 (0.47-0.94) and 0.62 (0.43-0.89), respectively. For small vessel occlusion (17.8%), outcomes tended to vary by white matter hyperintensitiy volume (P = 0.10, Cochran-Mantel-Haenszel test), and the highest quintile was associated with worse 3-month modified Rankin Scale scores: adjusted odds ratio for the fifth quintile versus first quintile, 1.98 (1.23-3.18). In this subtype, worse white matter hyperintensities were associated with worse National Institute of Health Stroke Scale scores at presentation. For cardioembolism (20.6%), outcomes did not vary significantly by white matter hyperintensity volume (P = 0.19, Cochran-Mantel-Haenszel test); however, the adjusted odds ratio for the highest versus lowest quintiles was 1.62 (1.09-2.40). Regardless of stroke subtype, white matter hyperintensities were not associated with stroke recurrence within 3 months of follow-up. In conclusion, white matter hyperintensity volume independently correlates with stroke outcomes in acute ischaemic stroke. There are some suggestions that stroke outcomes may be affected by leukoaraiosis differentially depending on stroke subtypes, to be confirmed in future investigations.

Obesity and stroke: Can we translate from rodents to patients?

Obesity is a risk factor for stroke and is consequently one of the most common co-morbidities found in patients. There is therefore an identified need to model co-morbidities preclinically to allow better translation from bench to bedside. In preclinical studies, both diet-induced and genetically obese rodents have worse stroke outcome, characterised by increased ischaemic damage and an altered inflammatory response. However, clinical studies have reported an 'obesity paradox' in stroke, characterised by reduced mortality and morbidity in obese patients. We discuss the potential reasons why the preclinical and clinical studies may not agree, and review the mechanisms identified in preclinical studies through which obesity may affects stroke outcome. We suggest inflammation plays a central role in this relationship, as obesity features increases in inflammatory mediators such as C-reactive protein and interleukin-6, and chronic inflammation has been linked to worse stroke risk and outcome.

Low-dose intravenous tissue plasminogen activator for acute ischaemic stroke: an alternative or a new standard?

BACKGROUND

With the recent publication of a large clinical trial on the use of a lower dose of intravenous (IV) tissue plasminogen activator (tPA) for acute ischaemic stroke (AIS), the concept of using a different dose has been debated. We intend to review the literature on using a lower dose of IV tPA and gain a better understanding of the impact of different IV doses on the treatment of patients with AIS.

METHODS

A comprehensive literature search of the related topics in PubMed, EMBASE, Web of Science and MEDLINE was carried out. Key words used include low dose IV tPA, thrombolysis, Alteplace and tPA for AIS. Findings were tabulated according to the size of the cohort studied, outcome, adverse event and level of evidence. The results of all studies using lower doses were analysed for efficacy and adverse events.

RESULTS

From 1992 to 2016, there were 23 trials that included 10 950 patients published on the use of lower doses of IV tPA for AIS. Doses ranged from 0.5, 0.6, 0.75 to 0.85 mg/kg. Most were observational, retrospective and registry studies. One was a prospective open-label randomised controlled trial. 13 trials combined lower doses of IV tPA with a glycoprotein IIb/IIIa inhibitor or thrombectomy. Patients treated with lower doses of IV tPA showed a trend of lower rate of symptomatic intracranial haemorrhage and mortality at 3 months but slightly more disability.

CONCLUSIONS

Lower doses of IV tPA showed less haemorrhagic events but were not more effective compared with the standard dose. The optimal low dose of IV tPA remains unclear. Patients with AIS with a high risk of developing sypmtomatic intracranial haemorrhage might benefit from lower dose IV tPA, such as 0.6 mg/kg.

Circulating cell-free DNA is a predictor of short-term neurological outcome in stroke patients treated with intravenous thrombolysis

Circulating cell-free DNA (cfDNA) has been described as a prognostic marker for several diseases. Its prognostic value for short-term outcome in stroke patients treated with intravenous thrombolysis remains unexplored. cfDNA was measured on admission in 54 tissue plasminogen activator (tPA)-treated patients and 15 healthy controls using a real-time quantitative polymerase chain reaction assay. Neurological outcome was assessed at 48 h. Predictors of neurological improvement were evaluated by logistic regression analysis, and the additional predictive value of cfDNA over clinical variables was determined by integrated discrimination improvement (IDI). Stroke patients presented higher baseline cfDNA than healthy controls (408.5 (179-700.5) vs. 153.5 (66.9-700.5) kilogenome-equivalents/L, p = 0.123). A trend towards lower cfDNA levels was found in patients who neurologically improved at 48 h (269.5 (143.3-680) vs. 504 (345.9-792.3) kilogenome-equivalents/L, p = 0.130). In logistic regression analysis, recanalization at 1 h and cfDNA < 302.75 kilogenome-equivalents/L was independently associated with neurological improvement after adjustment by age, gender and baseline National Institutes of Health Stroke Scale score. The addition of cfDNA to the clinical predictive model improved its discrimination (IDI = 21.2% (9.2-33.3%), p = 0.009). These data suggest that cfDNA could be a surrogate marker for monitoring tPA efficacy by the prediction of short-term neurological outcome.

History, Evolution, and Importance of Emergency Endovascular Treatment of Acute Ischemic Stroke

More than 800,000 people in North America suffer a stroke each year, with ischemic stroke making up the majority of these cases. The outcomes of ischemic stroke range from complete functional and cognitive recovery to severe disability and death; outcome is strongly associated with timely reperfusion treatment. Historically, ischemic stroke has been treated with intravenous thrombolytic agents with moderate success. However, five recently published positive trials have established the efficacy of endovascular treatment in acute ischemic stroke. In this review, we will discuss the history of stroke treatments moving from various intravenous thrombolytic drugs to intra-arterial thrombolysis, early mechanical thrombectomy devices, and finally modern endovascular devices. Early endovascular therapy failures, recent successes, and implications for current ischemic stroke management and future research directions are discussed.

Early neurological stability predicts adverse outcome after acute ischemic stroke

Background Deterioration in the National Institutes of Health Stroke Scale (NIHSS) in the early days after stroke is associated with progressive infarction, brain edema, and/or hemorrhage, leading to worse outcome. Aims We sought to determine whether a stable NIHSS score represents an adverse or favorable course. Methods Brain magnetic resonance images from a research cohort of acute ischemic stroke patients were analyzed. Using NIHSS scores at baseline and follow-up (day 3-5), patients were categorized into early neurological deterioration (ΔNIHSS ≥ 4), early neurological recovery (ΔNIHSS ≤ -4) or early neurological stability (ΔNIHSS between -3 and 3). The association between these categories and volume of infarct growth, volume of swelling, parenchymal hemorrhage, and 3-month modified Rankin Scale score were evaluated. Results Patients with early neurological deterioration or early neurological stability were less likely to be independent (modified Rankin Scale = 0-2) at 3 months compared to those with early neurological recovery ( P < 0.001). Patients with early neurological deterioration or early neurological stability were observed to have significantly greater infarct growth and swelling volumes than those with early neurological recovery ( P = 0.03; P < 0.001, respectively). Brain edema was more common than the other imaging markers investigated and was independently associated with a stable or worsening NIHSS score after adjustment for age, baseline stroke volume, infarct growth volume, presence of parenchymal hemorrhage, and reperfusion ( P < 0.0001). Conclusions Stable NIHSS score in the subacute period after ischemic stroke may not be benign and is associated with tissue injury, including infarct growth and brain edema. Early improvement is considerably more likely to occur in the absence of these factors.

Review : Neuroprotection in Brain Ischemia: An Update (Part II

Ischemic brain injury produced by stroke or cardiac arrest is a major cause of human neurological disability. Steady advances in the neurosciences have elucidated the pathophysiological mechanisms of brain ischemia and have suggested many therapeutic approaches to achieve neuroprotection of the acutely ischemic brain that are directed at specific injury mechanisms. In the second portion of this two-part review, the following potential therapeutic approaches to acute ischemic injury are considered: 1) modulation of nonglutamatergic neurotransmission, including monoaminergic systems (dopamine, norepinephrine, serotonin), γ-aminobutyric acid, and adenosine; 2) mild-to-moderate therapeutic hypothermia; 3) calcium channel antagonism; 4) an tagonism of oxygen free radicals; 5) modulation of the nitric oxide system; 6) antagonism of cytoskeletal proteolysis; 7) growth factor administration; 8) therapy directed at cellular mediators of injury; and 9) the rationale for combination pharmacotherapy. The Neuroscientist 1:164-175, 1995

Ultrasound Enhanced Thrombolysis for Stroke

In the pivotal clinical trials of intravenous tissue plasminogen activator (TPA) therapy, a low rate of early arterial recanalization was suspected because only a few stroke patients may have had early dramatic clinical improvement. Tissue plasminogen activator activity can be enhanced with ultrasound, including 2 MHz transcranial Doppler (TCD). Transcranial Doppler identifies residual blood flow signals around thrombi, and, by delivering mechanical pressure waves, exposes more thrombus surface to circulating TPA. For the first time in clinical medicine, the international multicenter CLOTBUST trial showed that ultrasound enhances the thrombolytic activity of a drug in humans, thereby confirming multidisciplinary experimental research conducted worldwide for the past 30 years. In the CLOTBUST trial, the dramatic clinical recovery from stroke coupled with complete recanalization within 2 h after TPA bolus occurred in 25% of patients treated with TPA+TCD compared with 8% who received TPA alone ( P = 0·02). Complete clearance of a thrombus and dramatic recovery of brain functions during treatment are feasible goals for ultrasound-enhanced thrombolysis that can lead to sustained recovery. An early boost in brain perfusion seen in the target CLOTBUST group resulted in a trend of 13% more patients achieving favorable outcome at 3 months. To further enhance the ability of TPA to break up thrombi, current ongoing clinical trials include phase II studies of 2 MHz TCD with ultrasound contrast agents or (microbubbles): TCD+TPA+Levovist; TCD+TPA+MRX nano-platform (C3F8). Intra-arterial TPA delivery can be enhanced with 1·7–2·1 MHz pulsed wave ultrasound (EKOS catheter, IMS trial). Dose escalation studies of microbubbles, ultrasound exposure, and the development of an operator-independent ultrasound device are underway.

Tenecteplase versus alteplase in stroke thrombolysis: An individual patient data meta-analysis of randomized controlled trials

Background

Tenecteplase, a modified plasminogen activator with higher fibrin specificity and longer half-life, may have advantages over alteplase in acute ischemic stroke thrombolysis.

Aims

We undertook an individual patient data meta-analysis of randomized controlled trials that compared alteplase with tenecteplase in acute stroke.

Methods

Eligible studies were identified by a MEDLINE search, and individual patient data were acquired. We compared clinical outcomes including modified Rankin Scale at three months, early neurological improvement at 24 h, intracerebral hemorrhage, symptomatic intracerebral hemorrhage, and mortality at three months between all dose tiers of tenecteplase and alteplase.

Results

Three relevant studies (Haley et al., Parsons et al., and ATTEST) included 291 patients and investigated three doses of tenecteplase (0.1, 0.25, 0.4 mg/kg). There were no differences between any dose of tenecteplase and alteplase for either efficacy or safety end points. Tenecteplase 0.25 mg/kg had the greatest odds to achieve early neurological improvement (OR [95%CI] 3.3 [1.5, 7.2], p = 0.093), excellent functional outcome (modified Rankin Scale 0–1) at three months (OR [95%CI] 1.9 [0.8, 4.4], p = 0.28), with reduced odds of intracerebral hemorrhage (OR [95%CI] 0.6 [0.2, 1.8], P = 0.43) compared with alteplase. Only 19 patients were treated with tenecteplase 0.4 mg/kg, which showed increased odds of symptomatic intracerebral hemorrhage compared with alteplase (OR [95% CI] 6.2 [0.7, 56.3]).

Conclusions

While no significant differences between tenecteplase and alteplase were found, point estimates suggest potentially greater efficacy of 0.25 and 0.1 mg/kg doses with no difference in symptomatic intracerebral hemorrhage, and potentially higher symptomatic intracerebral hemorrhage risk with the 0.4 mg/kg dose. Further investigation of 0.25 mg/kg tenecteplase is warranted.

Ischemic stroke outcome: A review of the influence of post-stroke complications within the different scenarios of stroke care

Stroke remains one of the main causes of death and disability worldwide. The challenge of predicting stroke outcome has been traditionally assessed from a general point of view, where baseline non-modifiable factors such as age or stroke severity are considered the most relevant factors. However, after stroke occurrence, some specific complications such as hemorrhagic transformations or post stroke infections, which lead to a poor outcome, could be developed. An early prediction or identification of these circumstances, based on predictive models including clinical information, could be useful for physicians to individualize and improve stroke care. Furthermore, the addition of biological information such as blood biomarkers or genetic polymorphisms over these predictive models could improve their prognostic value. In this review, we focus on describing the different post-stroke complications that have an impact in short and long-term outcome across different time points in its natural history and on the clinical-biological information that might be useful in their prediction.

Telestroke-the promise and the challenge. Part one: growth and current practice

Acute ischemic stroke remains a major public health concern, with low national treatment rates for the condition, demonstrating a disconnection between the evidence of treatment benefit and delivery of this treatment. Intravenous thrombolysis and endovascular thrombectomy are both strongly evidence supported and exquisitely time sensitive therapies. The mismatch between the distribution and incidence of stroke presentations and the availability of specialist care significantly affects access to care. Telestroke, the use of telemedicine for stroke, aims to surmount this hurdle by distributing stroke expertise more effectively, through video consultation with and examination of patients in locations removed from specialist care. This is the first of a detailed two part review, and explores the growth and current practice of telestroke, including the specific role it plays in the assessment and management of patients after emergent large vessel occlusion.

Acute Ischemic Stroke with Very Early Clinical Improvement: A National Institute of Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator Stroke Trials Exploratory Analysis

BACKGROUND

A high proportion of patients excluded from recombinant tissue plasminogen activator (rt-PA) treatment because of rapid improvement occurring before treatment decision had incomplete recovery. The National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Trials dataset allows for systematic analyses of very early postrandomization improvement (VEPRIM) in stroke severity as a National Institutes of Health Stroke Scale (NIHSS) score was available for all subjects enrolled in the study at baseline (NIHSSB) and at 2 hours after randomization (NIHSS2H). We explored various definitions of VEPRIM to characterize predictive values for clinical outcomes.

METHODS

Post hoc analyses of the NINDS rt-PA Stroke Trials were conducted. VEPRIM was defined as the difference between the NIHSSB and the NIHSS2H scores using 3 approaches: raw, percent, and normalized change. We assessed the association between VEPRIM and 3-month favorable outcome (mRS score of 0-1), symptomatic intracerebral hemorrhage (sICH), and death.

RESULTS

In the 624 subjects, every VEPRIM definition was independently associated with an increased probability of favorable outcome: for each unit of change within the VEPRIM definitions, there were 2%-24% (all P < .05) relative increased probability of favorable outcome, 2%-15% (all P < .05) decreased likelihood of death, and 2%-13% (all P < .05) decreased likelihood of sICH. Adjusting for NIHSSB and prestroke mRS scores, there was a significant rt-PA treatment effect for improvement seen for all 3 VEPRIM definitions.

CONCLUSIONS

VEPRIM predicted favorable outcomes independent of definition and treatment arm. Patients with VEPRIM by any definition, while doing better than patients without VEPRIM, also derived increased clinical benefit when treated with rt-PA compared to placebo. Even with VEPRIM, a substantial percentage of patients had unfavorable outcomes.

Low-Dose Versus Standard-Dose Tissue Plasminogen Activator in Acute Ischemic Stroke in Asian Populations: A Meta-Analysis

Recent studies have investigated the most efficacious dose of intravenous tissue plasminogen activator (IV-tPA) for acute ischemic stroke (AIS) patients. There remains no definitive consensus concerning the superior efficacious IV-tPA dose (standard- vs. low-dose), prompting us to perform a meta-analysis comparing the efficacy and safety profile of standard- versus low-dose IV-tPA.We identified relevant studies pertaining to the specific aim of our meta-analysis by searching PubMed and EMBASE (January 1990-September 2015) Either a fixed- or random-effects model was employed (dependent upon data heterogeneity) to analyze the efficacy and safety outcome.Ten cohort studies involving 4389 sum patients were included in the meta-analysis. By using the random-effects model, the meta-analysis indicated no statistically significant difference in favorable functional outcome (modified Rankin scale 0-1) at 3 months (heterogeneity: χ = 17.45, P = 0.04, I = 48%; OR: 0.88 [95% CI: 0.71-1.11]; P = 0.28) and incidence of symptomatic intracranial hemorrhage (SICH) (heterogeneity: χ = 14.41, P = 0.11, I = 38%; OR: 1.19 [95% CI: 0.76 to 1.87]; P = 0.45) between the standard- and low-dose groups. The fixed-effects model demonstrated no significant difference in mortality within 3 months (heterogeneity: χ = 6.73, P = 0.57, I = 0%; OR: 0.91 [95% CI: 0.73-1.12]; P = 0.37) between the standard- and low-dose groups.Low-dose IV-tPA is comparable to standard-dose IV-tPA in both efficacy (favorable functional outcome) and safety (SICH and mortality). Confirmation of these findings through randomized trials is warranted.

Intravenous Thrombolysis for Acute Ischemic Stroke Within 3 Hours Versus Between 3 and 4.5 Hours of Symptom Onset

Data from randomized clinical trials have supported the safety and efficacy of intravenous tissue-type plasminogen activator (IV tPA) for acute ischemic stroke when administered within 3 hours of symptom onset, and regulatory approvals for this indication have been in place for almost 20 years. However, recent clinical trials have provided evidence that IV tPA may be safe and effective in selected patients up to 4.5 hours after symptom onset, thereby increasing the proportion of patients that may be eligible for treatment. Although professional organizations in the United States and many regulatory agencies internationally have supported this expanded time window for IV tPA, the US Food and Drug Administration has declined to approve this expanded indication and so this use of IV tPA has remained off-label in the United States. Here we review the current evidence for IV tPA in the standard and the expanded time windows and the data on current clinical practice in the United States as it relates to IV tPA treatment for acute stroke within 3 to 4.5 hours of symptom onset.

Statistical analysis plan for evaluating low- vs. standard-dose alteplase in the ENhanced Control of Hypertension and Thrombolysis strokE stuDy (ENCHANTED)

Background

The ENhanced Control of Hypertension And Thrombolysis strokE stuDy trial is a 2 × 2 quasi‐factorial active‐comparison, prospective, randomized, open, blinded endpoint clinical trial that is evaluating in thrombolysis‐eligible acute ischemic stroke patients whether: (1) low‐dose (0·6 mg/kg body weight) intravenous alteplase has noninferior efficacy and lower risk of symptomatic intracerebral hemorrhage compared with standard‐dose (0·9 mg/kg body weight) intravenous alteplase; and (2) early intensive blood pressure lowering (systolic target 130–140 mmHg) has superior efficacy and lower risk of any intracerebral hemorrhage compared with guideline‐recommended blood pressure control (systolic target <180 mmHg).

Objective

To outline in detail the predetermined statistical analysis plan for the ‘alteplase dose arm’ of the study.

Methods

All data collected by participating researchers will be reviewed and formally assessed. Information pertaining to the baseline characteristics of patients, their process of care, and the delivery of treatments will be classified, and for each item, appropriate descriptive statistical analyses are planned with appropriate comparisons made between randomized groups. For the trial outcomes, the most appropriate statistical comparisons to be made between groups are planned and described.

Results

A statistical analysis plan was developed for the results of the alteplase dose arm of the study that is transparent, available to the public, verifiable, and predetermined before completion of data collection.

Conclusions

We have developed a predetermined statistical analysis plan for the ENhanced Control of Hypertension And Thrombolysis strokE stuDy alteplase dose arm which is to be followed to avoid analysis bias arising from prior knowledge of the study findings.

Treatment of acute ischemic stroke: from fibrinolysis to neurointervention

Thrombolytic therapy with intravenous recombinant tissue plasminogen activator is well established as a beneficial treatment for patients presenting with acute ischemic stroke (AIS). The odds of a favorable clinical outcome (living independently) increase as the time between stroke onset and treatment with IV thrombolysis decreases. However, many patients present with a large clot burden that seldom responds to systemic fibrinolysis. Alternative options include new and emerging endovascular therapies that have recently proven effectiveness at restoring cerebral blood flow to the ischemic brain parenchyma. This review article will briefly outline some of the key evidence for intravenous thrombolysis as well as endovascular therapy for AIS.

Rationale, Design, and Progress of the ENhanced Control of Hypertension ANd Thrombolysis Stroke Study (ENCHANTED) Trial: An International Multicenter 2 × 2 Quasi-Factorial Randomized Controlled Trial of Low- vs. Standard-Dose rt-PA and Early Intensive vs. Guideline-Recommended Blood Pressure Lowering in Patients with Acute Ischaemic Stroke Eligible for Thrombolysis Treatment

Rationale

Controversy exists over the optimal dose of intravenous (iv) recombinant tissue plasminogen activator (rt-PA) and degree of blood pressure (BP) control in acute ischaemic stroke (AIS). Asian studies suggest low-dose (0·6 mg/kg) is more efficacious than standard-dose (0·9 mg/kg) iv rt-PA, and guidelines recommend reducing systolic BP to <185 mmHg before and <180 mmHg after use of iv rt-PA, despite observational studies indicating better outcomes at much lower (<140 mmHg) systolic BP levels in this patient group.

Aims

The study aims to assess in thrombolysis-eligible AIS patients whether: (i) low-dose (0·6 mg/kg body weight; maximum 60 mg) iv rt-PA has non-inferior efficacy and lower risk of symptomatic intracerebral haemorrhage (sICH) compared to standard-dose (0·9 mg/kg body weight; maximum 90 mg) iv rt-PA; and (ii) early intensive BP lowering (systolic target 130–140 mmHg) has superior efficacy and lower risk of any ICH compared to guideline-recommended BP control (systolic target < 180 mmHg).

Design

The ENhanced Control of Hypertension And Thrombolysis strokE stuDy (ENCHANTED) trial is an independent, 2 × 2 quasi-factorial, active-comparison, prospective, randomized, open blinded endpoint (PROBE), clinical trial that is evaluating Arm [A] ‘rt-PA dose’ and/or Arm [B] ‘BP control’, using central Internet randomization and data collection in patients fulfilling local criteria for thrombolysis and clinician uncertainty over the study treatments. The treatment arms will be analyzed separately.

Study outcomes

The primary study outcome in both trial Arms is death or disability according to the modified Rankin scale (mRS, scores 2–6) assessed at 90 days. Secondary outcomes include sICH, any ICH, a shift (‘improvement’) in function across mRS scores, separately on death and disability, early neurological deterioration, recurrent major vascular events, health-related quality of life, length of hospital stay, need for permanent residential care, and health care costs.

Results

Following launch of the trial in February 2012, the study has recruited more than 2500 patients across a global network of approximately 100 sites in 15 countries. The required sample sizes are 3300 for Arm [A] and 2300 for Arm [B], which will provide >90% power to detect non-inferiority of low-dose iv rt-PA and superiority of intensive BP lowering on the primary clinical outcome, respectively.

Conclusions

Low-dose iv rt-PA and early intensive BP lowering could provide more affordable and safer use of thrombolysis treatment for patients with AIS worldwide.

Seven-Year Trends in Stroke Rehabilitation: Patient Characteristics, Medical Complications, and Functional Outcomes

Studies of stroke trends have focused primarily on incidence, mortality, and hospitalization rates. There has been little evaluation of changes over time in the common patient characteristics, medical comorbidities, and functional outcomes of patients. The present study evaluated changes during a 7-year period. We found that while demographic variables, stroke severity, and most stroke characteristics remained relatively stable, disability levels at admission and discharge decreased and frequencies of both medical tube usage and many secondary medical complications increased over time. These changes have important implications for the clinical management of stroke patients in rehabilitation and for the organization and financing of stroke rehabilitation programs.

Incidence, causes and predictors of neurological deterioration occurring within 24 h following acute ischaemic stroke: a systematic review with pathophysiological implications

Early neurological deterioration (END) following ischaemic stroke is a serious event with manageable causes in only a fraction of patients. The incidence, causes and predictors of END occurring within 24 h of acute ischaemic stroke (END24) have not been systematically reviewed. We systematically reviewed Medline and Embase from January 1990 to April 2013 for all studies on END24 following acute ischaemic stroke (<8 h from onset). We recorded the incidence and presumed causes of and factors associated with END24. Thirty-six studies were included. Depending on the definition used, the incidence of END24 markedly varied among studies. Using the most widely used change in National Institutes of Health Stroke Scale ≥4 definition, the pooled incidence was 13.8% following thrombolysis, ascribed to intracranial haemorrhage and malignant oedema each in ∼20% of these. As other mechanisms were rarely reported, in the majority no clear cause was identified. Few data on END24 occurring in non-thrombolysed patients were available. Across thrombolysed and non-thrombolysed samples, the strongest and most consistent admission predictors were hyperglycaemia, no prior aspirin use, prior transient ischaemic attacks, proximal arterial occlusion and presence of early CT changes, and the most consistent 24 h follow-up associated factors were no recanalisation/reocclusion, large infarcts and intracranial haemorrhage. Finally, END24 was strongly predictive of poor outcome. The above findings are discussed with emphasis on END without a clear mechanism. Data on incidence and predictors of the latter subtype is scarce, and future studies using systematic imaging protocols should address its underlying pathophysiology. This may in turn lead to rational preventative and therapeutic measures for this ominous event.

Alteplase in acute ischemic stroke: putting the guidelines into practice

Intravenous recombinant tissue plasminogen activator (rt-PA or alteplase) is the only approved medical intervention for treatment of acute ischemic stroke within the first hours of symptom onset. In this article, we review the preliminary studies of rt-PA in acute ischemic stroke that led to US FDA approval of its use within 3 h of symptom onset. The studies on rt-PA for use beyond 3 h of symptom onset and future reperfusion therapies are discussed. Overviews of the clinical presentation and treatment of acute ischemic stroke and stroke systems of care are described.

Acute ischemic stroke: comparison of low-dose and standard-dose regimes of tissue plasminogen activator

Intravenous tissue plasminogen activator (IV-TPA), administered within 4.5 h of symptom onset, is the only therapeutic agent approved for achieving arterial recanalization in acute ischemic stroke. Current major guidelines recommend the use of a standard dose (0.9 mg/kg bodyweight; maximum 90 mg) of IV-TPA. However, comparable efficacy of IV-TPA was demonstrated in the observational studies from Japan when a lower dose (0.6 mg/kg bodyweight; maximum 60 mg) was used and later approved by the regulatory authorities. Although limited in numbers, considerable variations in the dose of IV-TPA are noted in recent publications from Asia, with variable results and optimal dose of TPA in Asia remains controversial. The authors present a systemic review of the existing literature and compare the efficacy and safety of standard-versus the low-dose IV-TPA therapy in acute ischemic stroke.

Current perspectives on the use of intravenous recombinant tissue plasminogen activator (tPA) for treatment of acute ischemic stroke

In 1995, the NINDS (National Institute of Neurological Disorders and Stroke) tPA (tissue plasminogen activator) Stroke Study Group published the results of a large multicenter clinical trial demonstrating efficacy of intravenous tPA by revealing a 30% relative risk reduction (absolute risk reduction 11%-15%) compared with placebo at 90 days in the likelihood of having minimal or no disability. Since approval in 1996, tPA remains the only drug treatment for acute ischemic stroke approved by the US Food and Drug Administration. Over the years, an abundance of research and clinical data has supported the safe and efficacious use of intravenous tPA in all eligible patients. Despite such supporting data, it remains substantially underutilized. Challenges to the utilization of tPA include narrow eligibility and treatment windows, risk of symptomatic intracerebral hemorrhage, perceived lack of efficacy in certain high-risk subgroups, and a limited pool of neurological and stroke expertise in the community. With recent US census data suggesting annual stroke incidence will more than double by 2050, better education and consensus among both the medical and lay public are necessary to optimize the use of tPA for all eligible stroke patients. Ongoing and future research should continue to improve upon the efficacy of tPA through more rapid stroke diagnosis and treatment, refinement of advanced neuroimaging and stroke biomarkers, and successful demonstration of alternative means of reperfusion.

Alteplase for acute ischemic stroke

Alteplase, an intravenously administered form of recombinant tissue plasminogen activator (rt-PA), remains the only US FDA-approved thrombolytic treatment for acute ischemic stroke within 3 h of symptom onset. Patients treated with intravenous rt-PA are at least 30% more likely to have minimal or no disability at 3 months compared with placebo. Despite an increased risk of symptomatic intracranial hemorrhage, rt-PA does not increase mortality. The benefit achieved with rt-PA is cost effective and sustained 1 year after treatment. Despite its clear benefit, rt-PA remains underutilized. Although the future of acute ischemic stroke treatment will most likely involve a multi-faceted treatment approach, the primary objective remains to establish recanalization of the involved vessel. For patients with acute ischemic stroke within the first 3 h of symptom onset, rt-PA remains the first step in accomplishing this goal.

Onset of Orolingual Angioedema After Treatment of Acute Brain Ischemia with Alteplase Depends on the Site of Brain Ischemia: A Meta-analysis

Background:

Alteplase is used to treat acute ischemic stroke. However, it has several documented adverse effects, including the development of orolingual angioedema (OA). Although, OA is a rare side-effect, it is thought to be life-threatening and is difficult to treat. Until date, little is known about this condition and a better understanding of OA may contribute to improve the morbidity and mortality amongst patients that develop this condition.

Materials and Methods:

Using the PubMed and Medknow databases, we searched for peer reviewed published articles on OA after alteplase administration in 1950-2012. We gathered demographic data and investigated the relationship between the location of OA, neurological symptoms and the site of cerebral ischemia. In addition, we studied the effects of hypertensive premedication on OA development. We identified 19 published manuscripts that fulfilled our search criteria. These manuscripts reported 41 cases of OA after alteplase administration.

Results:

We found that this condition is associated with cerebral ischemia (P < 0.012) and that 65.9% (n = 27) of patients who developed OA had a hypertensive drug as a premedication.

Conclusions:

Although OA is a rare side-effect of alteplase, it can occur depending upon the localization of acute cerebral ischemia.

Prognostic Value of Plasma Chitotriosidase Activity in Acute Stroke Patients

Background and aims

Chitotriosidase, a component of innate immunity, constitutes a sensitive parameter of macrophage activation and its elevated plasma activity reflects an inflammatory response. Given the deleterious effects of inflammation in brain ischemia, we aimed to assess the prognostic value of chitotriosidase activity in acute stroke patients.

Methods

The study comprised 159 acute stroke patients and 51 age-matched controls. Plasma chitotriosidase activity was serially determined by fluorometric assay. Short-term neurological outcome was determined at 48 h and functional outcome at three-months. Predictors of neurological and functional outcome were determined via multivariate analysis, and the additional predictive value of chitotriosidase was tested with the Integrated Discrimination Index and the Net Reclassification Improvement.

Results

Stroke patients showed increased levels of baseline chitotriosidase activity compared to controls [114·2 (74·65–182·95) nmol/ml/h vs. 54·4 (32·7–76·4); P < 0·0001]. Chitotriosidase activity (<118·75) was found to be an independent predictor of neurological improvement at 48 h (odds ratio: 3·25; 95% confidence interval: 1·54–6·85; P = 0·002), and the addition of plasma chitotriosidase activity showed a better prediction of improvement at 48 h (Integrated Discrimination Index = 5·7%, Net Reclassification Improvement = 11·6%, P < 0·05) over the predictive model constituted only with clinical information. Although patients disabled at three-months showed higher baseline chitotriosidase levels, it was not an independent predictor of long-term disability.

Conclusions

Baseline chitotriosidase activity in acute stroke patients treated with tissue plasminogen activator (tPA) may constitute a prognostic predictor of short-term outcome, adding a moderate additional predictive value. Our results underline the deleterious role of inflammation in acute stroke patients.

Low-dose tissue plasminogen activator and standard-dose tissue plasminogen activator in acute ischemic stroke in Asian populations: a review

BACKGROUND

The burden of stroke is becoming an important issue in Asian countries, where half of the world's population lives. In Western populations, standard-dose intravenous tissue plasminogen activator (tPA) at a dose of 0.9 mg/kg administered up to 4.5 h following acute ischaemic stroke has been shown to improve clinical outcomes. However, the dosage of tPA in Asian populations varies, partly influenced by treatment costs in developing countries and the perceived racial differences in treatment response. Furthermore, no randomized controlled trial of intravenous tPA thrombolysis has been carried out in Asia with the exceptions of observational and multicentre registries in Japan. SUMMARY OF THE REVIEW: This review aims to examine the current use of low-dose tPA in Asian populations with particular emphasis on its clinical benefits. Historically, the findings of 2-chain tPA (duteplase) trials in the early 1990s were the basis of low-dose tPA in Japan, and standard-dose tPA was chosen taking into account a pilot dose escalation study. Most of the trials incorporating low-dose tPA suggested that low-dose tPA has clinical efficacy comparable with the standard dose and that it is associated with a lower incidence of symptomatic haemorrhage. It follows that consensus regarding the dosage of tPA is wanting.

CONCLUSIONS

Standard-dose tPA would be a reasonable choice in Asian populations until the results are available from randomized controlled studies comparing low-dose with standard-dose tPA.

Levine SR, Khatri P, Broderick JP, Grotta JC, Kasner SE, Kim D, Meyer BC, Panagos P, Romano J, Scott P. Review, historical context, and clarifications of the NINDS rt-PA stroke trials exclusion criteria: Part 1: rapidly improving stroke symptoms

BACKGROUND AND PURPOSE

Since Food and Drug Administration approval of intravenous tissue-type plasminogen activator (tPA) for treatment of acute ischemic stroke in 1996, it has become clear that several criteria used for exclusion from therapy were not based on actual data or operationally defined for use in clinical practice. All eligibility criteria from the National Institute of Neurological Disorders and Stroke (NINDS) recombinant tPA Stroke Study were adopted within the alteplase package insert as contraindications/warnings. Many clinicians have expressed the need for clarification and better definition of these treatment criteria.

METHODS

A group of investigators who also practice as stroke physicians convened a collaborative endeavor to work toward developing more clinically meaningful and consensus-driven exclusion criteria for intravenous tPA. The first of these exclusion criteria chosen was rapidly improving stroke symptoms (RISS). We reviewed and clarified the historical context and intention with the original investigators, held e-mail discussions, convened an in-person RISS Summit, and obtained the understanding of experienced stroke physicians broadly.

RESULTS

Historically, the intent of this exclusion criterion within the NINDS recombinant tPA Stroke Trial was to avoid treatment of transient ischemic attacks-who would have recovered completely without treatment. There was unanimous consensus that, in the absence of other contraindications, patients who experience improvement of any degree, but have a persisting neurological deficit that is potentially disabling, should be treated with intravenous tPA. This statement is supported from the methods established for the original NINDS trial, on the basis of detailed discussions and interviews with the former NINDS trialists. It was agreed that improvement should only be monitored for the extent of time needed to prepare and administer the intravenous tPA bolus/infusion. An explicit operational definition of RISS was developed by consensus to guide future decision making in acute stroke. There was unanimous agreement that all neurological deficits present at the time of the treatment decision should be considered in the context of individual risk and benefit, as well as the patient's baseline functional status.

CONCLUSIONS

A structured framework and quantitative approach toward defining RISS emerged through expert opinion and consensus. The term, RISS, should be reserved for those who improve to a mild deficit, specifically one which is perceived to be nondisabling. This is recommended to guide decision making on intravenous tPA eligibility going forward, including the design of future studies. An additional study of patients with rapid improvement to nonmild deficits is not justified because these patients should be treated.

Review of stroke thrombolytics

The cornerstone of acute ischemic stroke treatment relies on rapid clearance of an offending thrombus in the cerebrovascular system. There are various drugs and different methods of assessment to select patients more likely to respond to treatment. Current clinical guidelines recommend the administration of intravenous alteplase (following a brain noncontract CT to exclude hemorrhage) within 4.5 hours of stroke onset. Because of the short therapeutic time window, the risk of hemorrhage, and relatively limited efficacy of alteplase for large clot burden, research is ongoing to find more effective and safer reperfusion therapy, as well as focussing on refinement of patient selection for acute reperfusion treatment. Studies using advanced imaging (incorporating perfusion CT or diffusion/perfusion MRI) may allow us to use thrombolytics, or possibly endovascular therapy, in an extended time window. Recent clinical trials have suggested that Tenecteplase, used in conjunction with advanced imaging selection, resulted in more effective reperfusion than alteplase, which translated into increased clinical benefit. Studies using Desmoteplase have suggested its potential benefit in a sub-group of patients with large artery occlusion and salveageable tissue, in an extended time window. Other ways to improve acute reperfusion approaches are being actively explored, including endovascular therapy, and the enhancement of thrombolysis by ultrasound insonation of the clot (sono-thrombolysis).

Unanswered questions in thrombolytic therapy for acute ischemic stroke

This article reviews some of the current literature in support or against extension of the intravenous tissue plasminogen activator window, use of intra-arterial therapy or devices, as well alternative pharmacologic therapies that may extend the window for treatment of patients with acute ischemic stroke, with consideration of the relative risk of thrombolytic complications, factors for worse outcomes, and unclear stroke onset, as seen in patients with wake-up stroke. The issue of newer concomitant antithrombotic therapies as they affect the decision for acute ischemic stroke thrombolytic therapy is also explored.

Genes involved in hemorrhagic transformations that follow recombinant t-PA treatment in stroke patients

Aim: Despite the benefits of recombinant t-PA (rt-PA) for stroke patients some of them suffer from adverse hemorrhagic transformations (HTs) following treatment. Our objective is to study the transcriptomics of HTs patients. Methods: We studied by microarrays 11 blood samples from patients with stroke that had received rt-PA of whom six of them had suffered a HT. For replication step RNA was collected from 14 new subjects (seven with HT, seven without) and then analyzed by real-time PCR. Four proteins were measured by ELISA in 72 new subjects to analyze their role as potential protein biomarkers. Results: The microarray analysis revealed that 14 genes were altered among the HT patients. The replication study confirmed these results for six genes. Two of them (BCL2 and OLFM4) are associated with apoptosis, whereas the other four (LTF, LCN2 [also known as NGAL], CEACAM8 and CRISP3) are involved in the regulation of neutrophil processes. Conclusion: Our data revealed that genes related to apoptosis and neutrophil regulation pathways could be associated with HTs after rt-PA.

Original submitted 7 September 2012; Revision submitted 23 January 2013

Hyperacute direct thrombus imaging using computed tomography and gold nanoparticles

OBJECTIVE

Advancing the understanding and management of thromboembolic stroke requires simple and robust new methods that would be useful for the in vivo assessment of thrombus burden/distribution and for characterizing its evolution in a prompt and quantitative manner.

METHODS

Animals (n=127) with experimental models of thrombosis were imaged with microcomputed tomography 5 minutes (and/or ~3 weeks) after intravenous injection of glycol chitosan (GC) gold nanoparticles (AuNPs).

RESULTS

Nanoparticles accumulated in the thrombus, allowing computed tomography visualization of both the presence and extent of primary and recurrent thrombi in mouse carotid arteries without a single failure of detection. Nanoparticle thrombus imaging was also effective in monitoring the therapeutic efficacy of thrombolysis (n=118 tissue plasminogen activator [tPA] therapies). Thrombus evolution (either spontaneous or post-tPA) could be mapped at high resolution in both space and time. Due to a long circulating half-life, GC-AuNPs remain available for entrapment into fibrin matrix for an extended period of time (up to 3 weeks), allowing repetition or ongoing monitoring of thrombogenesis and thrombolysis.

INTERPRETATION

This is the first report on a hyperacute direct thrombus imaging technique using thrombus-seeking AuNPs and computed tomography. When translated into stroke practice, the thrombus imaging may allow us to advance to personalized thrombolytic therapy by demonstrating thrombus burden, distribution, and character in a prompt and quantitative manner. Further study into this area is indicated.

CT angiography in an acute stroke protocol: correlation between occlusion site and outcome of intravenous thrombolysis

Thrombolysis with intravenous rt-PA is the current therapy for acute ischemic stroke. Unlike other outcome factors, relatively little is known about the prognostic value of the occlusion site on treatment outcome. We compared the effectiveness and safety of intravenous thrombolysis in patients with different levels of occlusion identified by CT angiography (CTA) in anterior circulation stroke, and analyzed the influence of the occlusion site on treatment outcome in relation to other outcome factors. We selected 71 patients from a stroke database collected between June 2007 and December 2011 at our hospital. All of the studied patients had anterior circulation stroke with intracranial occlusion detected by CTA and were treated with intravenous rt-PA. They were divided into two groups according to the site of occlusion along the middle cerebral artery course: proximal (carotid "T", complete M1 and mild M1 occlusions) and distal (M2/M3 occlusions). Treatment effectiveness was assessed by modified Rankin Scale (mRS) at three months, considering a positive outcome a mRS value ≤ 2. Treatment safety was assessed by evaluating the rate of hemorrhagic complications seen on unenhanced CT at 24 hours. Binary logistic regression was performed to evaluate the interaction between occlusion site and other variables such as sex, age, ASPECT score on admission and baseline NIHSS value in determining treatment outcome. The degree of effectiveness and safety differed when considering patients with proximal and distal occlusions. The percentage of successfully treated cases was 28.6% in the first group compared to 72% in the second, and the rate of hemorrhagic complications was 28.6% and 6% respectively. After adjustment for sex, age, ASPECT score on admission and baseline NIHSS value, occlusion site was the only variable significantly influencing treatment safety and, together with baseline NIHSS value, the only valid predictor of treatment effectiveness. We demonstrated a correlation between the site of arterial occlusion and outcome of intravenous thrombolysis. By helping the choice of the best therapeutic strategy depending on the identified occlusion site, CTA could be usefully added to the examinations included in the Stroke Protocol for the baseline evaluation of patients with suspected acute stroke.

Thrombolysis in the developing world: is there a role for streptokinase?

Intravenous thrombolysis with tissue plasminogen activator is the only proven acute therapy for ischemic stroke. This therapy has not been translated into clinical practice in the developing world primarily due to economic constraints. Streptokinase, a lower cost alternative thrombolytic agent, is widely available in developing countries where it is utilized to treat patients with acute coronary syndromes. Although this drug has previously been found to be ineffective in ischemic stroke, the lack of benefit may have been related to a number of factors related to trial design rather than the drug itself. Specific features of prior trial designs that may have adversely affected outcomes include a prolonged treatment window, inclusion of patients with established infarction on computed tomography scan, failure to treat excessive arterial pressures, a fixed dose of streptokinase, and concomitant use of antithrombotic medications. Given the lack of therapeutic alternatives in developing countries, a new trial of streptokinase in acute stroke, utilizing stricter inclusion criteria similar to those in more recent thrombolytic studies, appears warranted.

Influence of hematoma location on acute mortality after intracerebral hemorrhage

BACKGROUND AND PURPOSE

This study aimed to identify predictors of acute mortality after intracerebral hemorrhage (ICH), including voxel-wise analysis of hematoma location.

METHODS

In 282 consecutive patients with acute ICH, clinical and radiological predictors of acute mortality were identified. Voxel-based lesion-symptom mapping examined spatial correlates of acute mortality, contrasting results in basal ganglia ICH and lobar ICH.

RESULTS

Acute mortality was 47.9%. In bivariate analyses, one clinical (serum glucose) and two radiological (hematoma volume and intraventricular extension) measures significantly predicted mortality. The relationship was strongest for hematoma volume. Multivariable modeling identified four significant predictors of mortality (ICH volume, intraventricular extension, serum glucose, and serum hemoglobin), although this model only minimally improved the predictive value provided by ICH volume alone. Voxel-wise analysis found that for patients with lobar ICH, brain regions where acute hematoma was significantly associated with higher acute mortality included inferior parietal lobule and posterior insula; for patients with basal ganglia ICH, a large region extending from cortex to brainstem.

CONCLUSIONS

For patients with lobar ICH, acute mortality is related to both hematoma size and location, with findings potentially useful for therapeutic decision making. The current findings also underscore differences between the syndromes of acute deep and lobar ICH.