Elevated Calcium after Acute Ischemic Stroke Predicts Severity and Prognosis

The aim of this study is to investigate whether there is a correlation between serum calcium levels and clinical severity or functional outcome at discharge in Chinese patients with acute ischemic stroke. Data from 339 patients admitted to our hospital between July 2020 and July 2021 were analyzed. Baseline demographic and clinical information was collected within 24 h of admission, including serum calcium levels, stroke severity (measured by the National Institutes of Health Stroke Scale [NIHSS] score), and lesion volumes. The modified Rankin Scale [mRS] assessed functional outcomes at discharge. Our analysis showed that the median age of patients included in the study was 65 years (interquartile range [IQR], 60-70), and 60.8% were men. We found a positive correlation between serum calcium levels and stroke severity (r[spearman] = 0.266, P < 0.001), with calcium levels increasing as stroke severity increased. In a subgroup of 188 patients with available MRI data, serum calcium concentrations positively correlated with infarct size. Furthermore, in multivariate analysis, a calcium serum level in the highest quartile was associated with a higher risk of unfavorable outcome (odds ratios [OR] = 3.27; 95% confidence intervals [CI] = 1.91-5.59; P < 0.001). In conclusion, our study indicates that higher calcium serum levels are associated with stroke severity and early neurologic outcome after acute ischemic stroke, indicating that calcium may serve as a prognostic biomarker for stroke in Chinese patients.

Adjunctive cytoprotective therapies in acute ischemic stroke: a systematic review

With the introduction of endovascular thrombectomy (EVT), a new era for treatment of acute ischemic stroke (AIS) has arrived. However, despite the much larger recanalization rate as compared to thrombolysis alone, final outcome remains far from ideal. This raises the question if some of the previously tested neuroprotective drugs warrant re-evaluation, since these compounds were all tested in studies where large-vessel recanalization was rarely achieved in the acute phase. This review provides an overview of compounds tested in clinical AIS trials and gives insight into which of these drugs warrant a re-evaluation as an add-on therapy for AIS in the era of EVT. A literature search was performed using the search terms “ischemic stroke brain” in title/abstract, and additional filters. After exclusion of papers using pre-defined selection criteria, a total of 89 trials were eligible for review which reported on 56 unique compounds. Trial compounds were divided into 6 categories based on their perceived mode of action: systemic haemodynamics, excitotoxicity, neuro-inflammation, blood–brain barrier and vasogenic edema, oxidative and nitrosative stress, neurogenesis/-regeneration and -recovery. Main trial outcomes and safety issues are summarized and promising compounds for re-evaluation are highlighted. Looking at group effect, drugs intervening with oxidative and nitrosative stress and neurogenesis/-regeneration and -recovery appear to have a favourable safety profile and show the most promising results regarding efficacy. Finally, possible theories behind individual and group effects are discussed and recommendation for promising treatment strategies are described.

Calcium antagonists for acute ischemic stroke

BACKGROUND

The sudden loss of blood supply in ischemic stroke is associated with an increase of calcium ions within neurons. Inhibiting this increase could protect neurons and might reduce neurological impairment, disability, and handicap after stroke.

OBJECTIVES

To assess the effects of calcium antagonists for reducing the risk of death or dependency after acute ischemic stroke. We investigated the influence of different drugs, dosages, routes of administration, time intervals after stroke, and trial design on the outcomes.

SEARCH METHODS

The evidence is current to 6 February 2018. We searched the Cochrane Stroke Group Trials Register (6 February 2018), Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 2), MEDLINE Ovid (1950 to 6 February 2018), Embase Ovid (1980 to 6 February 2018), and four Chinese databases (6 February 2018): Chinese Biological Medicine Database (CBM-disc), China National Knowledge Infrastructure (CNKI), Chinese Scientific Periodical Database of VIP information, and Wanfang Data. We also searched the following trials registers: ClinicalTrials.gov, EU Clinical Trials Register, Stroke Trials Registry, ISRCTN registry, WHO International Clinical Trials Registry Platform, and Chinese Clinical Trial Registry, and we contacted trialists and researchers.

SELECTION CRITERIA

Randomized controlled trials comparing a calcium antagonist versus control in people with acute ischemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, extracted data, assessed risk of bias, and applied the GRADE approach to assess the quality of the evidence. We used death or dependency at the end of long-term follow-up (at least three months) in activities of daily living as the primary outcome. We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 34 trials involving 7731 participants. All the participants were in the acute stage of ischemic stroke, and their age ranged from 18 to 85 years, with the average age ranging from 52.3 to 74.6 years across different trials. There were more men than women in most trials. Twenty-six trials tested nimodipine, and three trials assessed flunarizine. One trial each used isradipine, nicardipine, PY108-608, fasudil, and lifarizine. More than half of these trials followed participants for at least three months. Calcium antagonists showed no effects on the primary outcome (risk ratio (RR) 1.05; 95% confidence interval (CI) 0.98 to 1.13; 22 trials; 22 studies; 6684 participants; moderate-quality evidence) or on death at the end of follow-up (RR 1.07, 95% CI 0.98 to 1.17; 31 trials; 7483 participants; moderate-quality evidence). Thirteen trials reported adverse events, finding no significant differences between groups. Most trials did not report the allocation process or how they managed missing data, so we considered these at high risk of selection and attrition bias. Most trials reported double-blind methods but did not state who was blinded, and none of the trial protocols were available.

AUTHORS' CONCLUSIONS

We found no evidence to support the use of calcium antagonists in people with acute ischemic stroke.

Neuroprotective strategies and the underlying molecular basis of cerebrovascular stroke

Stroke is a leading cause of disability in the US. Although there has been significant progress in the area of medical and surgical thrombolytic technologies, neuroprotective agents to prevent secondary cerebral injury and to minimize disability remain limited. Only limited success has been reported in preclinical and clinical trials evaluating a variety of compounds. In this review, the authors discuss the most up-to-date information regarding the underlying molecular biology of stroke as well as strategies that aim to mitigate this complex signaling cascade. Results of historical research trials involving N-methyl-d-aspartate and α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor antagonists, clomethiazole, antioxidants, citicoline, nitric oxide, and immune regulators have laid the groundwork for current progress. In addition, more recent studies involving therapeutic hypothermia, magnesium, albumin, glyburide, uric acid, and a variety of other treatments have provided more options. The use of neuroprotective agents in combination or with existing thrombolytic treatments may be one of many exciting areas of further development. Although past trials of neuroprotective agents in ischemic stroke have been limited, significant insights into mechanisms of stroke, animal models, and trial design have incrementally improved approaches for future therapies.

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

Elevated calcium after acute ischemic stroke: association with a poor short-term outcome and long-term mortality

BACKGROUND AND PURPOSE

An elevated intracellular calcium level is known to be a major initiator and activator of ischemic cell death pathway; however, in recent studies, elevated serum calcium levels have been associated with better clinical outcomes and smaller cerebral infarct volumes. The pathophysiological role played by calcium in ischemic stroke is largely unknown.

METHODS

Acute stroke patients from a prospective stroke registry, consecutively admitted during October 2002-September 2008, were included. Significant associations between the modified Rankin scale distribution at discharge and serum calcium or albumin-corrected calcium were identified using ordinal logistic regression analysis. Cox proportional hazard models were used for survival analysis.

RESULTS

Mean serum calcium and albumin-corrected calcium levels of the 1,915 participants on admission were 8.97±0.58 mg/dL and 9.07±0.49 mg/dL, respectively. Second [adjusted odds ratio 1.32 (95% confidence interval 1.07-1.61)] and third [1.24 (1.01-1.53)] tertiles of serum calcium level and the third [1.24 (1.01-1.53)] tertile of albumin-corrected calcium level were found to be independent risk factors for a poor discharge outcome. Significant relationships were observed with serum calcium [1.19 (1.03-1.38)] and albumin-corrected calcium [1.21(1.01-1.44)] as linear variables. However, only albumin-corrected calcium was associated with long-term mortality, third tertile [adjusted hazard ratio 1.40 (1.07-1.83)], and increase by 1 mg/dL [1.46 (1.16-1.84)].

CONCLUSIONS

Elevated albumin-corrected serum calcium levels are associated with a poorer short-term outcome and greater risk of long-term mortality after acute ischemic stroke.

The NIHSS supplementary motor scale: a valid tool for multidisciplinary recovery trials

BACKGROUND

There is a growing interest in therapies that may augment motor recovery that could be initiated in the acute stroke unit and maintained through the rehabilitation period. Homogenization of the currently fragmented stroke clinicometrics is necessary before such multidisciplinary trials can be conducted. The supplementary motor scale of the NIH Stroke Scale (SMS-NIHSS) is a simple and reliable scale for assessing proximal and distal motor function in the upper and lower extremities. We hypothesized that the currently underutilized SMS-NIHSS is a valid tool for assessing motor recovery with prognosticative value.

METHODS

We performed an analysis of SMS-NIHSS scores recorded in 1,281 patients enrolled in the Trial of ORG 10172 in Acute Stroke Treatment (TOAST). We plotted the probability of a favorable outcome (FO) and very favorable outcome (VFO) at 3 months based on the baseline SMS-NIHSS scores. In order to better study the relationship between SMS-NIHSS and 3-month functional outcome, we performed multivariate logistic regression analyses using both FO and VFO as outcome measures. Analyses were adjusted for potential confounders such as age, sex, side of the lesion, time from symptom onset to emergency room arrival, temperature, systolic blood pressure, blood glucose level and treatment group assignment (ORG 10172 vs. placebo). We also calculated the Spearman correlation coefficient between the SMS-NIHSS, Barthel Index (BI) and Glasgow Outcome Score (GOS) obtained at the 3-month visit.

RESULTS

The mean SMS-NIHSS scores were 8.18 at baseline and 4.68 at 3 months. The SMS-NIHSS scores showed a gradual improvement during the first 3 months after stroke. There was a linear relationship between the baseline SMS-NIHSS scores and the probability of an FO or VFO at 3 months. The SMS-NIHSS baseline score was an independent predictor of FO (OR = 0.86; 95% CI 0.84-0.87; p < 0.0001) and VFO (OR = 0.85; 95% CI 0.84-0.87; p < 0.0001) at 3 months after adjusting for confounders. The degree of improvement in the SMS-NIHSS scores from baseline to 3 months was also independently associated with FO and VFO (p < 0.0001). At 3 months, SMS-NIHSS scores showed a strong correlation with the BI (r = -0.70; p < 0.0001) and GOS (r = 0.73; p < 0.0001).

CONCLUSIONS

The SMS-NIHSS is a valid scale for assessing motor recovery with prognosticative value, and may be sensitive to changes during recovery. Given that the SMS-NIHSS is an extension of the widely accepted NIHSS, it could be easily implemented in trials conducted in a variety of clinical research settings, including acute stroke hospitals and rehabilitation units.

Effect of natural borneol on the pharmacokinetics and distribution of nimodipine in mice

The purpose of this study was to investigate the effect of natural borneol (NB) on the pharmacokinetics and distribution of nimodipine in mice. A single dose of nimodipine was administered intravenously (2 mg/kg) to mice pretreated with NB (250 mg/kg) or vehicle. Blood as well as brain, liver, and kidney tissue samples were collected at 5, 10, 20, 40, and 60 min post-dose nimodipine. The concentrations of nimodipine in plasma and tissues were determined by ultra performance liquid chromatography (UPLC) coupled with UV detection, and the pharmacokinetic parameters were calculated based on non-compartmental analysis. NB increased the plasma AUC5-60 min by 26 % compared to the vehicle. In addition, brain concentrations of nimodipine in NB-treated mice were significantly higher than those in control mice with the increased AUC5-60 min by 30 %. In liver and kidney, NB also caused 26 and 47 % increase in AUC5-60 min, respectively. These results implicated that NB may inhibit the metabolism or elimination of nimodipine and enhance its distribution in brain and kidney tissue.

Unsolved issues in the management of high blood pressure in acute ischemic stroke

High blood pressure is common in acute stroke patients. Very high as well as very low blood pressure is associated with poor outcome. Spontaneous fall of blood pressure within the first few days after stroke was associated both with neurological improvement and impairment. Several randomized trials investigated the pharmacological reduction of blood pressure versus control. Most trials showed no significant difference in their primary outcome apart from the INWEST trial which found an increase of poor outcome when giving intravenous nimodipine. Nevertheless, useful information can be extracted from the published data to help guide the clinician's decision. Blood pressure should only be lowered when it is clearly elevated, and early after onset, reduction should be moderate but may be achieved rapidly. No clear recommendations can be given on the substances to use; however, care should be taken with intravenous calcium channel blockers and angiotensin receptor antagonists. Two ongoing randomized trials will help to solve the questions on blood pressure management in acute stroke.

Calcium antagonists for acute ischemic stroke

BACKGROUND

The sudden loss of blood supply in ischemic stroke is associated with the increase of calcium ions within neurons. Inhibiting this increase could protect neurons and hence might reduce neurological impairment, disability and handicap after stroke.

OBJECTIVES

To determine whether calcium antagonists reduce the risk of death or dependency after acute ischemic stroke. To investigate the influence of different drugs, dosages, routes of administration, time intervals after stroke and trial design on the risk of a primary outcome.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (January 2012), MEDLINE (1950 to December 2011), EMBASE (1980 to December 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2011 issue 4) and four Chinese databases (December 2011): Chinese Biological Medicine Database (CBM-disc), China National Knowledge Infrastructure (CNKI), Chinese scientific periodical database of VIP information and Wanfang Data. We also contacted trialists and researchers.

SELECTION CRITERIA

All truly randomized trials comparing a calcium antagonist with control in patients with acute ischemic stroke.

DATA COLLECTION AND ANALYSIS

Two authors assessed all trials and extracted the data. We used death or dependency at the end of long-term follow-up (at least three months) in activities of daily living as the primary outcome. Analyses were, if possible, intention-to-treat.

MAIN RESULTS

We included 34 trials including 7731 patients. There was no effect of calcium antagonists on the primary outcome (risk ratio (RR) 1.05; 95% confidence interval (CI) 0.98 to 1.13), or on death at the end of follow-up (RR 1.07, 95% CI 0.98 to 1.17). Comparisons of different doses of nimodipine suggested that the highest doses were associated with poorer outcome.

AUTHORS' CONCLUSIONS

No evidence is available using calcium antagonists in patients with acute ischemic stroke is effective.

Guidelines for the treatment of acute ischaemic stroke

INTRODUCTION

Update of Acute Ischaemic Stroke Treatment Guidelines of the Spanish Neurological Society based on a critical review of the literature. Recommendations are made based on levels of evidence from published data and studies.

DEVELOPMENT

Organized systems of care should be implemented to ensure access to the optimal management of all acute stroke patients in stroke units. Standard of care should include treatment of blood pressure (should only be treated if values are over 185/105 mmHg), treatment of hyperglycaemia over 155 mg/dl, and treatment of body temperature with antipyretic drugs if it rises above 37.5 °C. Neurological and systemic complications must be prevented and promptly treated. Decompressive hemicraniectomy should be considered in cases of malignant cerebral oedema. Intravenous thrombolysis with rtPA should be administered within 4.5 hours from symptom onset, except when there are contraindications. Intra-arterial pharmacological thrombolysis can be considered within 6 hours, and mechanical thrombectomy within 8 hours from onset, for anterior circulation strokes, while a wider window of opportunity up to 12-24 hours is feasible for posterior strokes. There is not enough evidence to recommend routine use of the so called neuroprotective drugs. Anticoagulation should be administered to patients with cerebral vein thrombosis. Rehabilitation should be started as early as possible.

CONCLUSION

Treatment of acute ischaemic stroke includes management of patients in stroke units. Systemic thrombolysis should be considered within 4.5 hours from symptom onset. Intra-arterial approaches with a wider window of opportunity can be an option in certain cases. Protective and restorative therapies are being investigated.

Postischemic PKC activation rescues retrograde and anterograde long-term memory

Therapeutics for cerebral ischemia/hypoxia, which often results in ischemic stroke in humans, are a global unmet medical need. Here, we report that bryostatin-1, a highly potent protein kinase C (PKC) activator, interrupts pathophysiological molecular cascades and apoptosis triggered by cerebral ischemia/hypoxia, enhances neurotrophic activity, and induces synaptogenesis in rats. This postischemic therapeutic approach is further shown to preserve learning and memory capacity even 4 months later as well as long-term memory induced before the ischemic event. Our results of electromicroscopic and immunohistochemical analyses of neuronal and synaptic ultra-structure are consistent with a PKC-mediated synaptic remodeling and repair process that confers long-lasting preservation of spatial learning and memory before and after the cerebral ischemic/hypoxic event, suggesting a previously undescribed therapeutic modality for cerebral ischemia/hypoxia and ischemic stroke.

In-vivo and in-vitro studies on the effect of Huang-Lian-Jie-Du-Tang on nimodipine transport across rat blood-brain barrier

Huang-Lian-Jie-Du-Tang (HLJDT), an aqueous extract of Rhizoma Coptidis, Radix Scutellariae, Cortex Phellodendri and Fructus Gardeniae (3:2:2:3) is an important multi-herb remedy in traditional Chinese medicine (TCM). The aim of this study was to evaluate the effect of HLJDT on nimodipine transport across rat blood-brain barrier (BBB). It was found that in-vivo the brain concentrations of nimodipine significantly increased when rats were pretreated with HLJDT. In-vitro, the serum of HLJDT-treated rats increased the accumulation of nimodipine in primary cultured rat brain microvessel endothelial cells (rBMECs) and decreased the expression of P-glycoprotein (P-gp) on rBMECs. Our previous study showed that the peak concentration of baicalin and berberine in rats after administration of HLJDT was 5 mug mL(-1) and 10 ng mL(-1), respectively. This study showed that 5 mug mL(-1) baicalin significantly increased the accumulation of nimodipine in rBMECs, while 10 ng mL(-1) berberine had no effect on the accumulation of nimodipine in rBMECs. Both the in-vivo and in-vitro experimental findings indicated that HLJDT pretreatment may alter the transport of nimodipine across rat BBB.

Nimodipine semi-solid capsules containing solid dispersion for improving dissolution

The aim of this study was to improve the dissolution and, therefore, bioavailability of the poorly water-soluble and highly permeable drug nimodipine (NMD). Present research involved the preparation of a solid dispersion (SD) consisting of NMD, Eudragit-E100 and Plasdone-S630 by hot-melt extrusion (HME). Compared with pure drug and physical mixture, the dissolution of NMD was enhanced dramatically (about 80% within 30min). Adding the nimodipine solid dispersion (NMD-SD) powder to a mixture of Plasdone-S630 and PEG400, and then transferring it to hard HPMC capsules, resulted in nimodipine semi-solid capsules (NMD-SSC). The dissolution from NMD-SSC was increased further (about 95% in 20min). In addition, the relative bioavailability of the NMD-SSC (test) and Nimotop (reference) was determined in beagle dogs after a single dose (120mg NMD) in a randomized crossover, own-control study. The results suggested that there was no significant difference in the areas under the plasma concentration-time curve and the mean peak concentration between NMD-SSC (AUC(0-infinity)=2488+/-433nghmL(-1), Cmax=321+/-78ngml(-1)) and Nimotop (AUC0-infinity=2272+/-398nghmL(-1), Cmax=293+/-73ngmL(-1)) (P>0.05). However, the apparent rate of absorption of NMD from NMD-SSC (tmax=1.3h) was markedly faster than that from Nimotop (tmax=3.1h) (P<0.05), which indicates that as a fast release preparation, NMD-SSC is well absorbed.

Neuroprotection for ischemic stroke: past, present and future

Neuroprotection for ischemic stroke refers to strategies, applied singly or in combination, that antagonize the injurious biochemical and molecular events that eventuate in irreversible ischemic injury. There has been a recent explosion of interest in this field, with over 1000 experimental papers and over 400 clinical articles appearing within the past 6 years. These studies, in turn, are the outgrowth of three decades of investigative work to define the multiple mechanisms and mediators of ischemic brain injury, which constitute potential targets of neuroprotection. Rigorously conducted experimental studies in animal models of brain ischemia provide incontrovertible proof-of-principle that high-grade protection of the ischemic brain is an achievable goal. Nonetheless, many agents have been brought to clinical trial without a sufficiently compelling evidence-based pre-clinical foundation. At this writing, around 160 clinical trials of neuroprotection for ischemic stroke have been initiated. Of the approximately 120 completed trials, two-thirds were smaller early-phase safety-feasibility studies. The remaining one-third were typically larger (>200 subjects) phase II or III trials, but, disappointingly, only fewer than one-half of these administered neuroprotective therapy within the 4-6h therapeutic window within which efficacious neuroprotection is considered to be achievable. This fact alone helps to account for the abundance of "failed" trials. This review presents a close survey of the most extensively evaluated neuroprotective agents and classes and considers both the strengths and weakness of the pre-clinical evidence as well as the results and shortcomings of the clinical trials themselves. Among the agent-classes considered are calcium channel blockers; glutamate antagonists; GABA agonists; antioxidants/radical scavengers; phospholipid precursor; nitric oxide signal-transduction down-regulator; leukocyte inhibitors; hemodilution; and a miscellany of other agents. Among promising ongoing efforts, therapeutic hypothermia, high-dose human albumin therapy, and hyperacute magnesium therapy are considered in detail. The potential of combination therapies is highlighted. Issues of clinical-trial funding, the need for improved translational strategies and clinical-trial design, and "thinking outside the box" are emphasized.

Neuroprotection: where to now?

Neuroprotection is an attractive potential therapy for acute ischemic stroke and is based on the concept of the ischemic cascade. However, therapeutic use of neuroprotectants in human stroke has proved more difficult than initially realized. The turning point was the finding that an apparently ideal neuroprotectant, NXY-059, was not neuroprotective in human stroke following a number of well-conducted clinical trials. In spite of these difficulties, research in neuroprotection should continue but in a greatly modified form. A number of important issues need to be addressed, ranging from the quality of experimental studies through to the demonstration of compounds reaching the target ischemic penumbra. An incremental approach to neuroprotection research is outlined, including the demonstration of efficacy in human cell cultures and tissues.

Management of blood pressure after acute ischemic stroke: An evidence-based guide for the hospitalist

Hospitalists are frequently called upon to manage blood pressure after acute ischemic stroke. A review of both post infarction cerebral perfusion physiology and the data from randomized trials of antihypertensive therapy is necessary to explain why consensus guidelines for blood pressure management after stroke differ from those of other hypertensive emergencies. The peri-infarct penumbra is the central concept in understanding post ischemic cerebral perfusion. This area of impaired cerebral blood flow is dependent on mean arterial blood pressure and acute reduction of blood pressure may expand the area of infarction. Review of clinical trials fails to show benefit from reduction of blood pressure after ischemic stroke and current guidelines suggest antihypertensive therapy be employed if the systemic blood pressure is greater than 180/105 mmHg after tPA is employed, or 220/120 mmHg when tPA is not used. Induced hypertension remains a promising but unproven therapy in the acute setting, but the evidence for long term control of blood pressure to less than 140/80 mmHG for secondary prevention of stroke is strong. Adherence to guidelines is poor but it is recognized that current evidence is limited by a lack of trials in which blood pressure is titrated to a pre-specified goal, as is common in clinical practice.

Guidelines for the Early Management of Adults With Ischemic Stroke

Purpose— Our goal is to provide an overview of the current evidence about components of the evaluation and treatment of adults with acute ischemic stroke. The intended audience is physicians and other emergency healthcare providers who treat patients within the first 48 hours after stroke. In addition, information for healthcare policy makers is included.

Methods— Members of the panel were appointed by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee and represented different areas of expertise. The panel reviewed the relevant literature with an emphasis on reports published since 2003 and used the American Heart Association Stroke Council’s Levels of Evidence grading algorithm to rate the evidence and to make recommendations. After approval of the statement by the panel, it underwent peer review and approval by the American Heart Association Science Advisory and Coordinating Committee. It is intended that this guideline be fully updated in 3 years.

Results— Management of patients with acute ischemic stroke remains multifaceted and includes several aspects of care that have not been tested in clinical trials. This statement includes recommendations for management from the first contact by emergency medical services personnel through initial admission to the hospital. Intravenous administration of recombinant tissue plasminogen activator remains the most beneficial proven intervention for emergency treatment of stroke. Several interventions, including intra-arterial administration of thrombolytic agents and mechanical interventions, show promise. Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke is needed.

Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists

PURPOSE

Our goal is to provide an overview of the current evidence about components of the evaluation and treatment of adults with acute ischemic stroke. The intended audience is physicians and other emergency healthcare providers who treat patients within the first 48 hours after stroke. In addition, information for healthcare policy makers is included.

METHODS

Members of the panel were appointed by the American Heart Association Stroke Council's Scientific Statement Oversight Committee and represented different areas of expertise. The panel reviewed the relevant literature with an emphasis on reports published since 2003 and used the American Heart Association Stroke Council's Levels of Evidence grading algorithm to rate the evidence and to make recommendations. After approval of the statement by the panel, it underwent peer review and approval by the American Heart Association Science Advisory and Coordinating Committee. It is intended that this guideline be fully updated in 3 years.

RESULTS

Management of patients with acute ischemic stroke remains multifaceted and includes several aspects of care that have not been tested in clinical trials. This statement includes recommendations for management from the first contact by emergency medical services personnel through initial admission to the hospital. Intravenous administration of recombinant tissue plasminogen activator remains the most beneficial proven intervention for emergency treatment of stroke. Several interventions, including intra-arterial administration of thrombolytic agents and mechanical interventions, show promise. Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke is needed.

Experimental treatments for acute ischaemic stroke

Treatments for acute ischaemic stroke continue to evolve. Experimental approaches to restore cerebral perfusion include techniques to augment recanalising therapies, including combination of antiplatelet agents with intravenous thrombolysis, bridging therapy of combining intravenous with intra-arterial thrombolysis, and trials of new thrombolytic agents. Trials with MRI selection criteria are underway to expand the window of opportunity for thrombolysis. Sonothrombolysis and novel endovascular mechanical devices to retrieve or dissolve acute cerebral occlusions are being tested. Approaches to improve cerebral perfusion with other devices and induced hypertension are also being considered. Although numerous neuroprotective agents have not shown benefit, trials of hypothermia, magnesium, caffeinol, high doses of statins, and albumin are continuing. The findings of these randomised trials are anticipated to allow improved treatment of patients with acute stroke.

Perspectives on neuroprotective stroke therapy

After years of setbacks, the perspective of neuroprotective stroke therapy has revived in light of recent study results. We outline in this review how a neuroprotective candidate drug should be developed, beginning with a thorough preclinical evaluation according to the STAIR (Stroke Therapy Academic Industry Roundtable) criteria. Assessing the safety of the candidate drug in the relatively straightforward Phase IIA would be the first step into clinical development. While advancing into Phase IIB, the implementation of a responder analysis, the use of a surrogate biomarker as well as the use of Bayesian methodology should be considered to increase the likelihood of seeing any therapeutic sign. Clinical development in Phase III should consider that previously used dichotomized endpoints appropriate for evaluation of thrombolytic drugs are likely to be insufficient for assessing efficacy of neuroprotective drugs. Detection of a clinically relevant shift in the outcome measure appears to be a more relevant approach for the type of drug that achieves a reduction and not a reverse of the ischaemic lesion.

Evolving therapeutic approaches to treating acute ischemic stroke

Stroke contributes significantly to death, disability, and healthcare costs; however, recombinant tissue plasminogen activator (rt-PA) is the only approved thrombolytic therapy for acute ischemic stroke. One area of development for new ischemic stroke treatment options is focused on neuroprotection of viable tissue in the ischemic vascular bed. The ischemic penumbra is recognizable on MRI by decreased perfusion, in contrast to the core area of ischemia, which includes diffusion and perfusion abnormalities. Understanding the mechanisms of neuronal death, including the role of excitotoxic neurotransmitters, free radical production, and apoptotic pathways, is important in developing new therapies for stroke. This article reviews these causes and results of stroke, as well as current and future neuroprotective treatment options. Several compounds have shown neuroprotective effects in animal studies, but have failed to be effective in human clinical trials. Several promising therapeutic areas include targeting of free radicals, modulation of glutamatergic transmission, and membrane stabilization via ion channels.

New Goals in Ischemic Stroke Therapy: The Experimental Approach – Harmonizing Science with Practice

Undeniable advances have been made in clinical and experimental investigation into the pathophysiology, diagnosis, and treatment of cerebral ischemia. However, with the exception of intravenous thrombolysis and some neuroprotectors, such as citicoline, the majority of the drugs successfully tested in experimental studies have failed in clinical trials. Valuable lessons for the improvement of research methodology and appropriate coordination of experimental and clinical research can be learnt from the analysis of discrepancies between the laboratory and clinic, which will allow us to increase the power and cost-effectiveness of the studies. In addition, this progress has opened the way for the investigation of very promising new therapeutic strategies, such as combined pharmacological and mechanical thrombolysis, thrombolysis and neuroprotection, or the combination of various neuroprotectors, antiapoptotic therapies, and neurorestoration therapies, such as stem cell transplants.

Neuroprotection for ischemic stroke: two decades of success and failure

Alteplase (rt-PA) is the first therapy successfully developed for acute stroke therapy. The success of rt-PA spurred development of new avenues for acute stroke management. For the last two decades, a great deal of attention has been paid to neuroprotective therapies. Initial preclinical studies demonstrated numerous drugs are effective for treating acute stroke in animal models; however, subsequent clinical trials have been frustrating, and none of the agents has proven effective. The various outcomes of preclinical and clinical trials have been the subject of much discussion. In this article, we review some key neuroprotective trials and the possible reasons for their failures. By identifying the discrepancies between preclinical studies and clinical trials, we may be able to set guidelines for future effective trials.

Ion channels involved in stroke

Ion channels are membrane proteins that flicker open and shut to regulate the flow of ions down their electrochemical gradient across the membrane and consequently regulate cellular excitability. Every living cell expresses ion channels, as they are critical life-sustaining proteins. Ion channels are generally either activated by voltage or by ligand interaction. For each group of ion channels the channels' molecular biology and biophysics will be introduced and the pharmacology of that group of channels will be reviewed. The in vitro and in vivo literature will be reviewed and, for ion channel groups in which clinical trials have been conducted, the efficacy and therapeutic potential of the neuroprotective compounds will be reviewed. A large part of this article will deal with glutamate receptors, focusing specifically on N-methyl-D-aspartate (NMDA) receptors. Although the outcome of clinical trials for NMDA receptor antagonists as therapeutics for acute stroke is disappointing, the culmination of these failed trials was preceded by a decade of efforts to develop these agents. Sodium and calcium channel antagonists will be reviewed and the newly emerging efforts to develop therapeutics targeting potassium channels will be discussed. The future development of stroke therapeutics targeting ion channels will be discussed in the context of the failures of the last decade in hopes that this decade will yield successful stroke therapeutics.

Treatments for stroke

Stroke is the third leading cause of death and the leading cause of disability in developed countries, yet remains a poorly treated condition. Treatments for stroke can be aimed at acutely improving blood flow or protecting brain tissue against ischaemia, enhancing stroke recovery or reducing the risk of stroke recurrence. This paper reviews each of these approaches, particularly focusing on mechanisms for which there are agents in clinical trials. There are a number of appealing neuroprotective agents in Phase II and III clinical trials. However, the majority of acute treatments are likely to suffer from a narrow therapeutic time window and hence limited patient access. Combinations of acute approaches are likely to offer the greatest benefit, but present challenges in development. Promotion of recovery following stroke offers enormous potential for successful therapeutic intervention. Excitingly, new developments in preclinical research have identified possible ways in which this may be achieved.

Determination of nimodipine in human plasma by a sensitive and selective liquid chromatography–tandem mass spectrometry method

A sensitive and highly selective liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to determine nimodipine in human plasma. The analyte and internal standard nitrendipine were extracted from plasma samples by n-hexane-dichloromethane-isopropanol (300:150:4, v/v/v), and chromatographed on a C(18) column. The mobile phase consisted of methanol-water-formic acid (80:20:1, v/v/v). Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI) source. The method has a limit of quantification of 0.24 ng/ml. The linear calibration curves were obtained in the concentration range of 0.24-80 ng/ml. The intra- and inter-day precisions were lower than 4.4% in terms of relative standard deviation (R.S.D.), and the accuracy ranged from 0.0 to 5.8% in terms of relative error (RE). This validated method was successfully applied for the evaluation of pharmacokinetic profiles of nimodipine tablets administered to 18 healthy volunteers.

Clinical trials for cytoprotection in stroke

To date, many cytoprotective drugs have reached the stage of pivotal phase 3 efficacy trials in acute stroke patients. (Table 1) Unfortunately, throughout the neuroprotective literature, the phrase "failure to demonstrate efficacy" prevails as a common thread among the many neutral or negative trials, despite the largely encouraging results encountered in preclinical studies. The reasons for this discrepancy are multiple, and have been discussed by Dr. Zivin in his review. Many of the recent trials have addressed deficiencies of the previous ones with more rigorous trial design, including more specific patient selection criteria (ensure homogeneity of stroke location and severity), stratified randomization algorithms (time-to-treat), narrowed therapeutic time-window and pharmacokinetic monitoring. Current trials have also incorporated biologic surrogate markers of toxicity and outcome such as drug levels and neuroimaging. Lastly, multi-modal therapies and coupled cytoprotection/reperfusion strategies are being investigated to optimize tissue salvage. This review will focus on individual therapeutic strategies and we will emphasize what we have learned from these trials both in terms of trial design and the biologic effect (or lack thereof) of these agents.

Combined nimodipine and citicoline reduce infarct size, attenuate apoptosis and increase bcl-2 expression after focal cerebral ischemia

Cerebral ischemia triggers a multitude of pathophysiological and biochemical events that separately affect the evolution of focal ischemia and, therefore, stroke treatment should logically employ all known neuroprotective agents. We hypothesized that a treatment combining nimodipine and citicoline might have a potential neuroprotective effect. To assess this idea, Sprague-Dawley rats underwent transient bilateral common carotid artery ligation with simultaneous middle cerebral artery occlusion for 60 min. Four treatment groups were established. Animals received either: a) saline (control group); b) intracarotid nimodipine infusion during 30 min in the ischemia-reperfusion (nimodipine group); c) i.p. postischemic citicoline injections once daily for 7 days (citicoline group); or d) intracarotid nimodipine bolus during ischemia-reperfusion plus i.p. postichemic citicoline injections (combination group). They were killed after either 7 or 3 days after reperfusion. In the first case, the volume of the infarcted tissue was studied by a stereological procedure and in the second case, in situ end-labeling of nuclear DNA fragmentation (TUNEL) and Bcl-2 expression were employed to determine the level of apoptosis. The infarct volume was significantly reduced in both the nimodipine and the citicoline treatment groups after 7 days of reperfusion; combination of both drugs produced an additive effect. After 3 days of reperfusion, the number of Bcl-2-positive neurons was significantly increased while that of TUNEL-positive cells significantly decreased at the infarct border in the combined-treatment animals. Our findings demonstrate a neuroprotective effect from an acute single dose of nimodipine during ischemia-reperfusion and prolonged post-ischemic treatment with citicoline in a model of focal cerebral ischemia. These results suggest that a possible mechanism of neuroprotective action would be mediated by increased Bcl-2 expression and decreased apoptosis within the boundary zone of the infarct together with neutralization of the ischemia-reperfusion injury.

Calcium entry through L-type calcium channels causes mitochondrial disruption and chromaffin cell death

Sustained, mild K+ depolarization caused bovine chromaffin cell death through a Ca(2+)-dependent mechanism. During depolarization, Ca(2+) entered preferentially through L-channels to induce necrotic or apoptotic cell death, depending on the duration of the cytosolic Ca(2+) concentration ([Ca(2+)](c)) signal, as proven by the following. (i) The L-type Ca(2+) channel activators Bay K 8644 and FPL64176, more than doubled the cytotoxic effects of 30 mm K+; (ii) the L-type Ca(2+) channel blocker nimodipine suppressed the cytotoxic effects of K+ alone or K+ plus FPL64176; (iii) the potentiation by FPL64176 of the K+ -evoked [Ca(2+)](c) elevation was totally suppressed by nimodipine. Cell exposure to K+ plus the L-type calcium channel agonist FPL64176 caused an initial peak rise followed by a sustained elevation of the [Ca(2+)](c) that, in turn, increased [Ca(2+)](m) and caused mitochondrial membrane depolarization. Cyclosporin A, a blocker of the mitochondrial transition pore, and superoxide dismutase prevented the apoptotic cell death induced by Ca(2+) overload through L-channels. These results suggest that Ca(2+) entry through L-channels causes both calcium overload and mitochondrial disruption that will lead to the release of mediators responsible for the activation of the apoptotic cascade and cell death. This predominant role of L-type Ca(2+) channels is not shared by other subtypes of high threshold voltage-dependent neuronal Ca(2+) channels (i.e. N, P/Q) expressed by bovine chromaffin cells.

Nimodipine in animal model experiments of focal cerebral ischemia: a systematic review

BACKGROUND AND PURPOSE

Based on the results of animal experiments, clinical trials were performed with nimodipine, which did not demonstrate a beneficial effect on outcome after stroke. The aim of this study was to determine whether the evidence from animal experiments with nimodipine supported the use of nimodipine in clinical trials.

METHODS

- We performed a systematic review of animal experiments with nimodipine in focal cerebral ischemia. Studies were identified by searching Medline and Embase. We assessed whether these studies showed a beneficial effect of active treatment. In-depth analyses were performed on infarct size and amount of edema, and subgroup analyses were performed on the length of the time window to the initiation of treatment and the methodological quality of the studies.

RESULTS

- Of 225 identified articles, 20 studies were included. The methodological quality of the studies was poor. Of the included studies, 50% were in favor of nimodipine. In-depth analyses showed statistically significant effects in favor of treatment (10 studies). No influence of the length of time to the initiation of treatment or of the methodological quality on the results was found.

CONCLUSIONS

- We conclude that the results of this review did not show convincing evidence to substantiate the decision to perform trials with nimodipine in large numbers of patients. There were no differences between the results of the animal experiments and clinical studies. Surprisingly, we found that animal experiments and clinical studies ran simultaneously.

Very Early Nimodipine Use in Stroke (VENUS): a randomized, double-blind, placebo-controlled trial

BACKGROUND AND PURPOSE

The Very Early Nimodipine Use in Stroke (VENUS) trial was designed to test the hypothesis that early treatment with nimodipine has a positive effect on survival and functional outcome after stroke. This was suggested in a previous meta-analysis on the use of nimodipine in stroke. However, in a recent Cochrane review we were unable to reproduce these positive results. This led to the early termination of VENUS after an interim analysis.

METHODS

In this randomized, double-blind, placebo-controlled trial, treatment was started by general practitioners or neurologists within 6 hours after stroke onset (oral nimodipine 30 mg QID or identical placebo, for 10 days). Main analyses included comparisons of the primary end point (poor outcome, defined as death or dependency after 3 months) and secondary end points (neurological status and blood pressure 24 hours after inclusion, mortality after 10 days, and adverse events) between treatment groups. Subgroup analyses (on final diagnosis and based on the per-protocol data set) were performed.

RESULTS

At trial termination, after inclusion of 454 patients (225 nimodipine, 229 placebo), no effect of nimodipine was found. After 3 months of follow-up, 32% (n=71) of patients in the nimodipine group had a poor outcome compared with 27% (n=62) in the placebo group (relative risk, 1.2; 95% CI, 0.9 to 1.6). A treatment effect was not found for secondary outcomes and in the subgroup analyses.

CONCLUSIONS

The results of VENUS do not support the hypothesis of a beneficial effect of early nimodipine in stroke patients.

Calcium antagonists for ischemic stroke: a systematic review

BACKGROUND AND PURPOSE

Stroke is a common disease, and many trials with calcium antagonists as possible neuroprotective agents have been conducted. The aim of this review is to determine whether calcium antagonists reduce the risk of death or dependency after acute ischemic stroke.

METHODS

Acute stroke trials were identified with help of the Cochrane Collaboration Stroke Group and personal contacts. All randomized trials (published and unpublished) investigating a calcium antagonist (acting on voltage-sensitive calcium channels) were included. Poor outcome, defined as death or dependency in activities of daily living, was used as main outcome. Analyses were, if possible, "intention-to-treat"; pooled relative risks with 95% CIs were calculated.

RESULTS

Forty-seven trials were identified, of which 29 were included (7665 patients). No effect of calcium antagonists on poor outcome at the end of follow-up (relative risk, 1.04; 95% CI, 0.98 to 1.09) or on death at end of follow-up (relative risk, 1.07; 95% CI, 0.98 to 1.17) was found. Sensitivity analyses on route of administration and time interval between stroke and start of treatment showed no effect on outcome. In subgroups of unpublished and methodologically sound trials, a statistically significant negative effect for calcium antagonists was found. This contrasts with results of published trials and trials of moderate or poor methodological quality.

CONCLUSIONS

The presented evidence rules out a clinically important effect of calcium antagonists after ischemic stroke. The large amount of data leads to narrow CIs with no significant heterogeneity, and the overall results are therefore likely to be statistically robust.

Recent advances in the diagnosis and treatment of stroke

Stroke is defined as an abnormality in brain function resulting from disruption of cerebral circulation. It is the third leading cause of death in the United States and the primary cause of long-term disability. The economic burden of stroke will only increase as the population ages, making prevention and treatment of stroke one of the most important public health issues of the upcoming millennium. New therapies for the treatment of acute stroke, especially thrombolysis, have turned what was once considered an inevitable deficit into a potentially treatable illness. It is increasingly important for all physicians to be able to identify symptoms of cerebral ischemia. Neurons have a very limited tolerance for ischemia, making the rapid evaluation and diagnosis of stroke critical. This is particularly relevant for the ophthalmologist, who may be the first physician to see individuals presenting with visual deficits. Trials are underway to look specifically at central retinal artery and basilar artery ischemia and their response to thrombolytic therapy. This review will focus on description of recent advances in treatment and diagnosis of stroke, including thrombolytic trials and the expanding role of neuroimaging.

Stroke: management and rehabilitation. Part III of III

The aim of this review is to present the current knowledge regarding stroke. It appears in three parts (in part I the epidemiology, clinical picture, and risk factors were discussed, while part II dealt with the pathogenesis, investigations, and prognosis). In this part (III) the management is presented. In an acute stroke the role of the following is discussed in detail: Thrombolysis, anticoagulant agents, and prophylactic neuroprotection with pharmacologic agents. For the prevention of stroke apart from the risk factors, which were presented in part I, the current knowledge with pharmacologic agents is discussed. Also the role of carotid endarterectomy, extracranial-intracranial bypass surgery, carotid artery angioplasty and stenting, and the treatment of cerebral hemorrhage are described. Finally the means and possibilities of rehabilitation are discussed.

Ischemic penumbra: evidence from functional imaging in man

The ischemic penumbra is defined as tissue with flow within the thresholds for maintenance of function and of morphologic integrity. Penumbra tissue has the potential for recovery and therefore is the target for interventional therapy in acute ischemic stroke. The identification of the penumbra necessitates measuring flow reduced less than the functional threshold and differentiating between morphologic integrity and damage. This can be achieved by multitracer positron emission tomography (PET) and perfusion-weighted (PW) and diffusion-weighted magnetic resonance imaging (DW-MRI) in experimental models, in which the recovery of critically perfused tissue or its conversion to infarction was documented in repeat studies. Neuroimaging modalities applied in patients with acute ischemic stroke--multitracer PET, PW- and DW-MRI, single photon emission computed tomography (SPECT), perfusion, and Xe-enhanced computed tomography (CT)-- often cannot reliably identify penumbra tissue: multitracer studies for the assessment of flow and irreversible metabolic damage usually cannot be performed in the clinical setting; CT and MRI do not reliably detect irreversible damage in the first hours after stroke, and even DW-MRI may be misleading in some cases: determinations of perfusion alone yield a poor estimate of the state of the tissue as long as the time course of changes is not known in individual cases. Therefore, the range of flow values in ischemic tissue found later, either within or outside the infarct, was rather broad. New tracers--for example, receptor ligands or hypoxia markers--might improve the identification of penumbra tissue in the future. Despite these methodologic limitations, the validity of the concept of the penumbra was proven in several therapeutic studies in which thrombolytic treatment reversed critical ischemia and decreased the volume of final infarcts. Such neuroimaging findings might serve as surrogate targets in the selection of other therapeutic strategies for large clinical trials.

Effect of intravenous nimodipine on blood pressure and outcome after acute stroke

BACKGROUND AND PURPOSE

The Intravenous Nimodipine West European Stroke Trial (INWEST) found a correlation between nimodipine-induced reduction in blood pressure (BP) and an unfavorable outcome in acute stroke. We sought to confirm this correlation with and without adjustment for prognostic variables and to investigate outcome in subgroups with increasing levels of BP reduction.

METHODS

Patients with a clinical diagnosis of ischemic stroke (within 24 hours) were consecutively allocated to receive placebo (n=100), 1 mg/h (low-dose) nimodipine (n=101), or 2 mg/h (high-dose) nimodipine (n=94). The correlation between average BP change during the first 2 days and the outcome at day 21 was analyzed.

RESULTS

Two hundred sixty-five patients were included in this analysis (n=92, 93, and 80 for placebo, low dose, and high dose, respectively). Nimodipine treatment resulted in a statistically significant reduction in systolic BP (SBP) and diastolic BP (DBP) from baseline compared with placebo during the first few days. In multivariate analysis, a significant correlation between DBP reduction and worsening of the neurological score was found for the high-dose group (beta=0.49, P=0. 048). Patients with a DBP reduction of > or =20% in the high-dose group had a significantly increased adjusted OR for the compound outcome variable death or dependency (Barthel Index <60) (n/N=25/26, OR 10. 16, 95% CI 1.02 to 101.74) and death alone (n/N=9/26, OR 4.336, 95% CI 1.131 16.619) compared with all placebo patients (n/N=62/92 and 14/92, respectively). There was no correlation between SBP change and outcome.

CONCLUSIONS

DBP, but not SBP, reduction was associated with neurological worsening after the intravenous administration of high-dose nimodipine after acute stroke. For low-dose nimodipine, the results were not conclusive. These results do not confirm or exclude a neuroprotective property of nimodipine.