Haemodilution for acute ischaemic stroke

Clinical Outcomes and Medical Costs of Hydration Therapy with Hydroxyethyl Starch (130/0.4) or Acute Single Infarction

OBJECTIVES

To investigate the effects of hydration with or without Hydroxyethyl Starch (HES) 130/0.4 on neurological outcomes and medical costs during hospitalisation in patients with a single infarction (SI) in the posterior lenticulostriate artery (LSA) territory.

MATERIALS AND METHODS

In this retrospective, single-centre, non-blinded cohort study, SI in the posterior LSA was defined as an ischaemic lesion with a high-signal intensity area ≥20 mm. All patients received basic stroke care within 48 h of symptom onset between April 2015 and January 2019. Patients were divided into the following two groups by clinician's preference: 1) those administered HES 130/0.4 and 2) those receiving other infusion fluid. The relationships between hospital costs and hydration therapy type were examined.

RESULTS

Eighteen (31%) of 58 patients received HES 130/0.4. The HES group had a significantly lower total cost than the control group (3.6 vs. 6.4 million yen, p=0.006). Moreover, the HES group had a significantly shorter hospital stay duration (79.5 vs. 141.0 days) and lower National Institutes of Health Stroke Scale score on day 7. Multivariate analysis found that HES 130/0.4 administration was an independent factor associated with high costs.

CONCLUSIONS

Hydration therapy with HES 130/0.4 significantly decreased the total costs and hospitalisation duration of patients with SI in the posterior LSA territory.

Blood Pressure and Penumbral Sustenance in Stroke from Large Vessel Occlusion

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

European Stroke Organisation (ESO) guidelines for prophylaxis for venous thromboembolism in immobile patients with acute ischaemic stroke

Background

Venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism is a frequent complication in immobile patients with acute ischemic stroke. This guideline document presents the European Stroke Organisation guidelines for the prophylaxis of VTE in immobile patients with acute ischaemic stroke. Guidelines for haemorrhagic stroke have already been published.

Methods

A multidisciplinary group identified related questions and developed its recommendations based on evidence from randomised controlled trials using the Grading of Recommendations Assessment, Development, and Evaluation approach. This guideline document was reviewed within the European Stroke Organisation and externally and was approved by the European Stroke Organisation Guidelines Committee and the European Stroke Organisation Executive Committee.

Results

We found mainly moderate quality evidence comprising randomised controlled trials and systematic reviews evaluating graduated compression stockings (GCS), intermittent pneumatic compression (IPC) and prophylactic anticoagulation with unfractionated (UFH) and low molecular weight heparins (LMWH) and heparinoids, but no randomised trials evaluating neuromuscular electrical stimulation (NES). We recommend that clinicians should use IPC in immobile patients, but that they should not use GCS. Prophylactic anticoagulation with UFH (5000U ×2, or ×3 daily) or LMWH or heparinoid should be considered in immobile patients with ischaemic stroke in whom the benefits of reducing the risk of VTE is high enough to offset the increased risks of intracranial and extracranial bleeding associated with their use. Where a judgement has been made that prophylactic anticoagulation is indicated LMWH or heparinoid should be considered instead of UFH because of its greater reduction in risk of DVT, the greater convenience, reduced staff costs and patient comfort associated single vs. multiple daily injections but these advantages should be weighed against the higher risk of extracranial bleeding, higher drug costs and risks in elderly patients with poor renal function associated with LMWH and heparinoids.

Conclusions

IPC, UFH or LMWH and heparinoids can reduce the risk of VTE in immobile patients with acute ischaemic stroke but further research is required to test whether NES is effective. The strongest evidence is for IPC. Better methods are needed to help stratify patients in the first few weeks after stroke onset, by their risk of VTE and their risk of bleeding on anticoagulants.

Blood Products

Perioperative hemorrhage, anemia, thrombocytopenia, and coagulopathy are common in the surgical intensive care unit. As a result, blood product transfusion occurs frequently. While red blood cell, plasma, and platelet transfusions have a lifesaving role in the resuscitation of patients with trauma and hemorrhagic shock, their application in other settings is under scrutiny. Current data would suggest a conservative approach be taken, thus avoiding unnecessary transfusion and associated potential adverse events. New and developmental products such as prothrombin complex concentrates offer appealing alternatives to traditional transfusion practice—potentially with fewer risks—however, further investigation into their safety and efficacy is required before practice change can take place.

Fluid Intake Related to Brain Edema in Acute Middle Cerebral Artery Infarction

Evidence of the appropriate amount of fluid intake during the first few days after acute stroke was scarce. Concerns were raised in patients with acute malignant middle cerebral infarction, who tended to have malignant brain edema later. The purpose of the study was to evaluate the effect of fluid intake on the occurrence of malignant brain edema in patients with acute middle cerebral artery infarction. Patients with acute middle cerebral artery infarction who had National Institute of Health Stroke Scale (NIHSS) score of at least 15 were included. Baseline characteristics and amount of fluid intake during the first few days were compared in patients with and without malignant brain edema. One hundred ninety-three patients were studied. Mean NIHSS score was 20. Malignant brain edema occurred in 69 patients (36%). Higher amount of fluid intake (>1650 ml or >28 ml/kg/day or >93% of daily maintenance fluid) showed a significant association with malignant brain edema (OR = 13.86, 95% CI 5.11-37.60, p value <0.001). Decompressive surgery was performed in 35 patients (18%). With mean follow-up of 12 months, 49 patients (49/184, 27%) had favorable outcomes (modified Rankin scale (mRS) 0-2) at final follow-up. Seventy-nine patients (79/184, 43%) died. In the subgroup of patients with malignant brain edema, 39 patients (39/65, 60%) died and only 11% (7/65 patients) had favorable outcome. High amount of fluid intake in the first few days of acute middle cerebral infarction was related to the occurrence of malignant brain edema.

A survey to establish current methods of venous thromboembolism prophylaxis in stroke patients practiced by Polish neurologists

INTRODUCTION

Venous thromboembolism (VTE) is associated with considerable morbidity and mortality in stroke patients. The purpose of our survey was to establish the current methods of VTE prophylaxis practiced by Polish neurologists. We also aimed to determine whether there is enough variation in practice to justify the development of an evidence-based guideline for VTE prevention.

MATERIAL AND METHODS

Postal self-administered questionnaires about VTE prophylactic methods practiced by Polish neurologists were sent to 218 neurological wards where stroke is treated. If no response was received, the questionnaire was faxed and finally we attempted to obtain information by telephone.

RESULTS

One hundred and seventy-six (80.7%) stroke centers of 218 responded. The majority (137/176; 77.8%) of centers had a stroke unit. The median admission rate of surveyed wards was estimated to be 320 patients/year (range from 20 to 1000 patients/year). The most common method of VTE prophylaxis reported was low molecular weight heparin (LMWH) (98.9%), and the least common was intermittent pneumatic compression (IPC) (6.8%). Centers admitting ≥ 200 patients/year (70.7% vs. 45%; p = 0.039), and those with stroke units (95 vs. 20; p = 0.031) were more willing to join a randomized trial evaluating any of the methods. All the centers participating in the survey reported a need for a detailed VTE prophylaxis guidelines.

CONCLUSIONS

The LMWH is the predominant VTE prophylaxis strategy for stroke patients practiced by Polish neurologists. Due to the variation of methods used in VTE prophylaxis it might be reasonable to further specify this section of stroke treatment guidelines.

Venous thromboembolism prophylactic methods in acute stroke patients - current state of knowledge

Deep venous thrombosis (DVT) and its sequel, pulmo-nary em-bolism (PE), are serious complications of stroke. There are pharmacological and physical methods to prevent these complications. The authors review the lite-rature and present the current state of knowledge re-garding the effectiveness of each of the DVT and PE prevention methods in stroke patients and cite current Polish, European and American recommendations re-garding this issue. Heparins are the method of choice for the prevention of venous thromboembolism in both ischaemic and haemorrhagic stroke patients.

Acute embolic cerebral ischemia as an initial presentation of polycythemia vera: a case report

Introduction

Patients with polycythemia vera are at high risk for vaso-occlusive events including cerebral ischemia. Although unusual, acute ischemic stroke may be an initial presentation of polycythemia vera. It had been previously assumed that cerebral ischemic events were due to increased blood viscosity and platelet activation within the central nervous system arterial vessels. However, there are now a few isolated case reports of probable micro-embolic events originating from outside of the brain. This suggests unique management issues for these patients.

Case presentation

We present the case of a 57-year-old right-handed Caucasian male in excellent health who presented to the Emergency Department with acute right-handed clumsiness. Hematologic investigations revealed a hyperviscous state and magnetic resonance imaging was consistent with cerebral emboli. Symptoms rapidly improved with phlebotomy and hydration.

Conclusion

The etiology of stroke in polycythemic patients is likely to be multifactorial. While hemodilution has been generally discredited for general stroke management, it is potentially beneficial for patients with polycythemia vera and euvolemic hemodilution should be considered for the polycythemic patient with acute cerebral ischemia.

Sex differences and hemoglobin levels in relation to stroke outcomes

OBJECTIVE

Women have worse outcomes after stroke compared to men. Since women have lower hemoglobin values, we examined whether hemoglobin levels may associate with worse stroke outcomes in women.

METHODS

We retrospectively studied 274 patients enrolled in a prospective multicenter study. We explored the relationship of hemoglobin with clinical outcome at 6 months, as measured by the modified Rankin Scale (mRS). Ordinal logistic regression was used to evaluate the independent effect of hemoglobin on clinical outcome, and to explore the influence of sex on that association.

RESULTS

Women had a lower mean hemoglobin level (11.7 ± 1.8 g/dL) compared to men (13.3 ± 1.7 g/dL). Low hemoglobin was associated with worse 6-month mRS outcomes in univariate analysis (p < 0.001). Lower hemoglobin remained independently associated with poor outcome after adjustment for comorbid disease, stroke severity, age, and sex. The inclusion of hemoglobin in the model attenuated the independent effect of sex on outcome.

CONCLUSIONS

Sex differences in stroke outcome are linked to lower hemoglobin level, which is more prevalent in women. Further examination of this potentially modifiable predictor is warranted.

Hydroxyethyl starch 130/0.4 and sodium chloride injection as adjunctive therapy in patients with cerebral hypoperfusion

BACKGROUND

Both severe stenosis and completed occlusion in internal carotid artery or its distal branches have been considered the main reasons of cerebral hypoperfusion, which contributes to the washout disturbances of embolism in low perfusion territories distal to stenosis. An aggravated hypoperfusion state in certain brain region may induce ischemic stroke and further cognitive decline. However, the effective medication for cerebral hypoperfusion is largely unsettled.

METHODS/DESIGN

By using computed tomography perfusion (CTP) imaging, the trial will evaluate the effectiveness, safety and tolerability of hydroxyethyl starch (HES) 130/0.4 for patients with extra-/intra-cranial artery stenosis and cerebral hypoperfusion. From 5 neurological inpatient wards, 300 patients will be randomly recruited for administered routine medications plus intravascular volume therapies using the equal volume of HES 130/0.4 or 0.9% sodium chloride solution. Cerebral hypoperfusion state after 7-day intervention is the primary outcome measure. The secondary outcome measures includes, impaired renal function, abnormal heart function, hematological changes, neurological dysfunctions and cerebrovascular events in peri-intervention period and/or 3-month follow-up. The sample size will allow the detection of a two-sided 5% significance level between groups in the endpoint with a power of 80%.

DISCUSSION

The trial would provide important efficacy and safety data on the intravascular administration of HES 130/0.4 in patients with unilateral cerebral hypoperfusion. The effects on kidney function, heart function, coagulation, neurological function and cerebralvascular events will be assessed.

TRIAL REGISTRATION

ClinicalTrials.gov (Identifier: NCT01192581).

Systematic analysis of hydroxyethyl starch (HES) reviews: proliferation of low-quality reviews overwhelms the results of well-performed meta-analyses

PURPOSE

Hydroxyethyl starch (HES) is a synthetic colloid used widely for resuscitation despite the availability of safer, less costly fluids. Numerous HES reviews have been published that may have influenced clinicians' practice. We have therefore examined the relationship between the methodological quality of published HES reviews, authors' potential conflicts of interest (pCOI) and the recommendations made.

METHODS

Systematic analysis of reviews on HES use.

RESULTS

Between 1975 and 2010, 165 reviews were published containing recommendations for or against HES use. From the 1990s onwards, favorable reviews increased from two to eight per year and HES's share of the artificial colloid market tripled from 20 to 60 %. Only 7 % (12/165) of these reviews of HES use contained meta-analyses; these 7 % had higher Overview Quality Assessment Questionnaire (OQAQ) scores [median (range) 6.5 (3-7)] than reviews without meta-analysis [2 (1-4); p < 0.001]. The rates of recommending against HES use are 83 % (10/12) in meta-analyses and 20 % (31/153) in reviews without meta-analysis (p < 0.0001). Fourteen authors published the majority (70/124) of positive reviews, and ten of these 14 had or have since developed a pCOI with various manufacturers of HES.

CONCLUSIONS

Low-quality HES reviews reached different conclusions than high-quality meta-analyses from independent entities, such as Cochrane Reviews. The majority of these low-quality positive HES reviews were written by a small group of authors, most of whom had or have since established ties to industry. The proliferation of positive HES reviews has been associated with increased utilization of an expensive therapy despite the lack of evidence for meaningful clinical benefit and increased risks. Clinicians need to be more informed that marketing efforts are potentially influencing scientific literature.

Red blood cell transfusion in the neurological ICU

Red blood cell transfusion (RBCT) is a common therapy used in the intensive care unit to treat anemia. However, due to deleterious side effects and questionable efficacy, the clinical benefit of RBCT in patients who are not actively bleeding is unclear. The results of randomized controlled trials suggest there is no benefit to a liberal transfusion practice in general critical care populations. Whether the results of these trials are applicable to brain injured patients is unknown, as patients with primary neurological injury were excluded. This article reviews the efficacy and complications of RBCT, as well as the relationship between RBCT and its outcome in both the general intensive care unit and neurologically critically ill populations.

Treatment of subarachnoid hemorrhage with human albumin: ALISAH study. Rationale and design

The primary objective of this prospective dose-finding pilot study is to demonstrate the tolerability and safety of four dosages of 25% human albumin in patients with subarachnoid hemorrhage (SAH). For each dosage group, the study will enroll 20 patients who meet the eligibility criteria. The enrolled patients will undergo follow-up for 90 days post-treatment. The primary tolerability hypothesis is that intravenous 25% human albumin can be given without precipitating treatment related serious adverse events beyond expectations. The study will determine the maximum tolerated dosage of 25% human albumin therapy based on the rate of treatment related serious adverse events during treatment: severe or life-threatening heart failure. The secondary objectives are to obtain preliminary estimates of the albumin treatment effect using the incidence of neurological deterioration within 15 days after symptom onset. In addition, the incidence of rebleeding, hydrocephalus, seizures, delayed cerebral ischemia and the incidence of vasospasm (both symptomatic and by transcranial Doppler ultrasound criteria) within 15 days after symptom onset will be evaluated. Furthermore, the serum osmolality and serum albumin concentrations, serum magnesium concentration, blood pressure and heart rate within 15 days of symptom onset will also be observed. The Glasgow Outcome Scale, Barthel Index, modified Rankin Scale, NIH Stroke Scale, and Stroke Impact Scale will be performed 3 months after the onset of symptoms to assess residual neurological deficits.

Potential role of PMD-TCD monitoring in the management of hemodynamically unstable intracranial stenosis

A 54-year-old woman started to loose vision 2 days prior to admission and also experienced left-sided headache, nausea, emesis, and disorientation. Magnetic resonance imaging (MRI) revealed bilateral posterior cerebral artery and cerebellar infarctions. Transcranial power motion Doppler (PMD-TCD) showed blunted flow signal in the proximal basilar artery (BA) suggestive for a high-grade stenosis also seen on magnetic resonance angiography (MRA). Dual antiplatelet therapy with aspirin and clopidogrel was started. Catheter angiography confirmed the proximal high-grade BA stenosis. After angiography, the patient experienced hypertensive crisis with severe headache. Blood pressure was lowered and headache resolved. One hour later she developed fluctuating level of consciousness and motor symptoms. PMD-TCD findings were suggestive for an intraluminal thrombus that moved from the proximal to the distal basilar artery, presumably further contributing to brain stem hypoperfusion and neurological deterioration. To achieve a compromise between lower blood pressure and maintenance of brain perfusion, hypervolemic hemodilution with intravenous dextran-40 was initiated. Patient's symptoms resolved to baseline and MRI showed no new parenchymal lesions.

Comparison of the post-embolization effects of tissue-plasminogen activator and simvastatin on neurological outcome in a clinically relevant rat model of acute ischemic stroke

Data has emerged, largely from non-thromboembolic animal models of stroke, that suggests that statins, which have efficacy in preventing strokes when given pre-ischemically, may have a positive effect on stroke even when given post-ischemically, possibly through pleitropic cerebrovascular effects. The goal of this study was to characterize the effects of IV tPA in a clinically relevant model of stroke utilizing a vascular occlusion with a freshly formed clot, and evaluate the effects of post-ischemic administration of simvastatin on stroke outcome in this model. Neurological deficit, clot burden, and lesion volume were assessed after treatment with tPA in one experiment, and after treatment with simvastatin in another. In the tPA experiment, treatment with 10mg/kg of tPA IV (with 20% given as an initial bolus, and 80% given as an infusion over the remaining 30 min), starting within an hour after stroke, resulted in significant reductions, compared with control animals, in neurological deficit (mean+/-SD neuroscores of 21.5+/-21.1 and 30+/-29.3, respectively, p=0.005), clot burden (p=0.010) and lesion volume (p=0.049) at 24h. In the simvastatin experiment on the other hand, treatment with a 20mg/kg of simvastatin as a single intraperitoneal dose within an hour after stroke resulted in no salutary effects on neurological deficit, clot burden or lesion volume compared with controls at 24h. These results suggest that more research needs to be done to fully ascertain the therapeutic potential and optimal dosing paradigm of a post-ischemic treatment with a statin.

Cerebrolysin for acute ischaemic stroke

BACKGROUND

Cerebrolysin is a mixture of low-molecular-weight peptides and amino acids derived from pigs' brain tissue which has proposed neuroprotective and neurotrophic properties. It is widely used in the treatment of acute ischaemic stroke in Russia and China.

OBJECTIVES

To assess the benefits and risks of cerebrolysin for treating acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (February 2009), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2009), MEDLINE (1966 to February 2009), EMBASE (1974 to February 2009), LILACS (1982 to February 2009), Science Citation Index (1940 to February 2009), SIGLE Archive (1980 to March 2005), and a number of relevant Russian Databases (1988 to February 2009). We also searched reference lists, ongoing trials registers and conference proceedings.

SELECTION CRITERIA

Randomised controlled trials comparing cerebrolysin with placebo or no treatment in patients with acute ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Three review authors independently applied the inclusion criteria, assessed trial quality and extracted the data.

MAIN RESULTS

We included one trial involving 146 participants. There was no difference in death (6/78 in the cerebrolysin group versus 6/68 in the placebo group; risk ratio (RR) 0.87, 95% confidence interval (CI) 0.29 to 2.58) or in the total number of adverse events (16.4% versus 10.3%; RR 1.62, 95% CI 0.69 to 3.82) between the treatment and control groups.

AUTHORS' CONCLUSIONS

There is not enough evidence to evaluate the effect of cerebrolysin on survival and dependency in people with acute ischaemic stroke. High-quality and large-scale randomised controlled trials may help to gain a better understanding of the potential value of cerebrolysin in acute ischaemic stroke.

Anemia status, hemoglobin concentration and outcome after acute stroke: a cohort study

BACKGROUND

In the setting of an acute stroke, anemia has the potential to worsen brain ischemia, however, the relationship between the entire range of hemoglobin to long-term outcome is not well understood.

METHODS

We examined the association between World Health Organization-defined admission anemia status (hemoglobin<13 in males, <12 g/dl in women) and hemoglobin concentration and 1-year outcome among 859 consecutive patients with acute stroke (ischemic or intracerebral hemorrhage).

RESULTS

The mean baseline hemoglobin concentration was 13.8 +/- 1.7 g/dl (range 8.1 - 18.7). WHO-defined anemia was present in 19% of patients among both women and men. After adjustment for differences in baseline characteristics, patients with admission anemia had an adjusted OR for all-cause death at 1-month of 1.90 (95% CI, 1.05 to 3.43) and at 1-year of 1.72 (95% CI, 1.00 to 2.93) and for the combined end-point of disability, nursing facility care or death of 2.09 (95% CI, 1.13 to 3.84) and 1.83 (95% CI, 1.02 to 3.27) respectively. The relationship between hemoglobin quartiles and all-cause death revealed a non-linear association with increased risk at extremes of both low and high concentrations. In logistic regression models developed to estimate the linear and quadratic relation between hemoglobin and outcomes of interest, each unit increment in hemoglobin squared was associated with increased adjusted odds of all-cause death [at 1-month 1.06 (1.01 to 1.12; p = 0.03); at 1-year 1.09 (1.04 to 1.15; p < 0.01)], confirming that extremes of both low and high levels of hemoglobin were associated with increased mortality.

CONCLUSIONS

WHO-defined anemia was common in both men and women among patients with acute stroke and predicted poor outcome. Moreover, the association between admission hemoglobin and mortality was not linear; risk for death increased at both extremes of hemoglobin.

Anemia and red blood cell transfusion in neurocritical care

INTRODUCTION

Anemia is one of the most common medical complications to be encountered in critically ill patients. Based on the results of clinical trials, transfusion practices across the world have generally become more restrictive. However, because reduced oxygen delivery contributes to 'secondary' cerebral injury, anemia may not be as well tolerated among neurocritical care patients.

METHODS

The first portion of this paper is a narrative review of the physiologic implications of anemia, hemodilution, and transfusion in the setting of brain-injury and stroke. The second portion is a systematic review to identify studies assessing the association between anemia or the use of red blood cell transfusions and relevant clinical outcomes in various neurocritical care populations.

RESULTS

There have been no randomized controlled trials that have adequately assessed optimal transfusion thresholds specifically among brain-injured patients. The importance of ischemia and the implications of anemia are not necessarily the same for all neurocritical care conditions. Nevertheless, there exists an extensive body of experimental work, as well as human observational and physiologic studies, which have advanced knowledge in this area and provide some guidance to clinicians. Lower hemoglobin concentrations are consistently associated with worse physiologic parameters and clinical outcomes; however, this relationship may not be altered by more aggressive use of red blood cell transfusions.

CONCLUSIONS

Although hemoglobin concentrations as low as 7 g/dl are well tolerated in most critical care patients, such a severe degree of anemia could be harmful in brain-injured patients. Randomized controlled trials of different transfusion thresholds, specifically in neurocritical care settings, are required. The impact of the duration of blood storage on the neurologic implications of transfusion also requires further investigation.

Volume and electrolyte management

Osmolality is the primary determinant of water movement across the intact blood-brain barrier (BBB), and we can predict that reducing serum osmolality would increase cerebral oedema and intracranial pressure. Brain injury affects the integrity of the BBB to varying degrees. With a complete breakdown of the BBB, there will be no osmotic/oncotic gradient, and water accumulates (brain oedema) consequentially to the pathological process. In regions with very moderate BBB injury, the oncotic gradient may be effective. Finally, osmotherapy is effective in brain areas with normal BBB; hypertonic solutions (mannitol, hypertonic saline) dehydrate normal brain tissue, with a decrease in cerebral volume and intracranial pressure. In patients with brain pathology, volume depletion and/or hypotension greatly increase morbidity and mortality. In addition to management of intravascular volume, fluid therapy must often be modified for water and electrolyte (mainly sodium) disturbances. These are common in patients with neurological disease and need to be adequately treated.

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.

Pressor Therapy in Acute Ischemic Stroke

Background and Purpose— Systolic blood pressure (SBP) levels below 140 mm Hg after acute stroke occur in 18% to 25% of patients, and may be associated with adverse outcome, in terms of death and disability. It has thus been proposed that BP elevation in acute ischemic stroke may be beneficial by increasing perfusion to the peri-infarct penumbra, though not only in those with low BP levels.

Methods— All articles studying BP elevation in the context of acute stroke were identified using a structured search strategy.

Results— Two reviewers independently searched the databases, and 12 relevant publications were identified. All identified publications related to acute ischemic stroke and no articles on pressor therapy in primary hemorrhagic stroke were found. The review included 319 subjects (age: 42 to 88 years, 46% male), with phenylephrine being the most commonly used pressor agent, though 8 studies incorporated volume expansion. Because of small numbers, and varying entry/outcome criteria, no meta-analysis of outcome measures was possible. Overall, in these few studies undertaken, pressor therapy in acute stroke appears feasible and well-tolerated. The benefit and risks in terms of clinical outcomes remains unknown, but intensive monitoring is advised if such therapy is undertaken.

Conclusions— Theoretical arguments exist for inducing BP elevation in acute ischemic stroke to increase blood flow to the ischemic penumbra across patients with a broad BP range. To date, there have only been a few small trials with inconclusive results. Many questions are still unanswered about the safety and potential benefits of pressor therapy in acute stroke. Hopefully, ongoing trials will answer some of these important questions.