Dichotomized efficacy end points and global end-point analysis applied to the ECASS intention-to-treat data set: post hoc analysis of ECASS I

Controversies in cerebrovascular disease: high or low doses of recombinant tissue plasminogen activator to treat acute stroke? A literature review

INTRODUCTION

The use of low doses of recombinant tissue plasminogen activator (rt-PA) was initially proposed in Asian countries in response to racial peculiarities related to the functionality of fibrinogen and coagulation factors that potentially increased the risk of intracerebral haemorrhage, and with a view to saving costs. In view of the controversy over the use of rt-PA below the standard dose, we conducted a literature review of studies promoting the use of low doses or comparing different doses of rt-PA.

DEVELOPMENT

We reviewed 198 abstracts related to the search terms and the full texts of 52 studies published in the last 30 years. We finally included 13 randomised clinical trials aiming to determine the efficacy and safety of the use of rt-PA at different doses in acute stroke, 14 observational cohort studies, 5 meta-analyses, and 3 systematic reviews.

CONCLUSIONS

There is insufficient evidence to classify low doses of rt-PA as superior or at least not inferior to the standard treatment in the management of acute stroke in western populations. More clinical trials are required to determine whether the use of low doses is beneficial in patients with relative contraindications for thrombolytic therapy or other particular circumstances that may increase the risk of intracerebral haemorrhage.

Controversies in cerebrovascular disease: High or low doses of recombinant tissue plasminogen activator to treat acute stroke? A literature review

INTRODUCTION

The use of low doses of recombinant tissue plasminogen activator (rt-PA) was initially proposed in Asian countries in response to racial peculiarities related to the functionality of fibrinogen and coagulation factors that potentially increased the risk of intracerebral haemorrhage, and with a view to saving costs. In view of the controversy over the use of rt-PA below the standard dose, we conducted a literature review of studies promoting the use of low doses or comparing different doses of rt-PA.

DEVELOPMENT

We reviewed 198 abstracts related to the search terms and the full texts of 52 studies published in the last 30 years. We finally included 13 randomised clinical trials aiming to determine the efficacy and safety of the use of rt-PA at different doses in acute stroke, 14 observational cohort studies, 5 meta-analyses, and 3 systematic reviews.

CONCLUSIONS

There is insufficient evidence to classify low doses of rt-PA as superior or at least not inferior to the standard treatment in the management of acute stroke in western populations. More clinical trials are required to determine whether the use of low doses is beneficial in patients with relative contraindications for thrombolytic therapy or other particular circumstances that may increase the risk of intracerebral haemorrhage.

Acute revascularization in ischemic stroke: Updated Swiss guidelines

In acute ischemic stroke, intravenous thrombolysis (IVT) and acute endovascular therapy (EVT) have been shown to reduce long-term disability in randomized trials. International guidelines are partially not up to date and may not address situations for which there is limited scientific evidence. The goals of the present guidelines are to summarize the current scientific data for acute revascularization treatments to make sure that all Swiss Centers apply a similar, evidence, or consensus-based treatment standard. A multidisciplinary working group of the Swiss Stroke Society (SSS) searched and reviewed the literature on new randomized controlled trials (RCTs), large case series, meta-analyses, and other guidelines since the previous recommendations in 2009 to elaborate the consensus guidelines. The new RCTs have confirmed the effectiveness of IVT in various populations up to 4.5 h and proven the benefit of acute EVT up to approximately 8 h. For patients with unknown onset (including wake-up stroke), IVT and EVT can be effective up to 24 h after last proof of good health if patients are selected with advanced neuroimaging. Multiple case series and meta-analyses allow narrowing down the indications and relative and absolute contraindications to optimize the benefit–risk ratio of acute revascularization.

Who may benefit from lower dosages of intravenous tissue plasminogen activator? Results from a cluster data analysis

Background

The risk of symptomatic intracranial haemorrhage (sICH) after thrombolysis is low but severe. Lower dose of alteplase may reduce the risk of sICH. We aim to identify subsets of patients who could benefit from lower dose of alteplase compared with standard dose.

Methods

Data from two observational registries were pooled together. A total of 3479 patients who had acute ischaemic stroke were entered into the interaction tree model. The response variable was the rate of sICH per the definition of the National Institute of Neurological Disorders and Stroke Study. Clinical improvement was measured by the National Institutes of Health Stroke Scale (NIHSS) and defined as NIHSS 0 or 1 or an improvement of more than 4 points (within 7 days or at discharge). Rare event logistic regression was performed to analyse the OR of safety outcome.

Results

To optimise the interaction effect between tissue plasminogen activator (tPA) dosage (standard/lower) and patient subgroups, three subgroups based on the severity of stroke were identified: (1) NIHSS ≤4, (2) NIHSS between 5 and 14, and (3) NIHSS ≥15. The estimated difference of OR of having sICH was 2.71 (95% CI 0.80 to 7.69, p=0.10) for mild, 0.13 (95% CI 0.02 to 0.68, p=0.01) for moderate, and 0.65 (95% CI 0.19 to 2.55, p=0.52) for severe, respectively. In addition, patients who had moderate stroke treated with lower dose had comparable efficacy outcome (OR 1.23, 95% CI 0.71 to 2.13, p=0.45).

Conclusion

Our analysis demonstrated that in patients who had moderate stroke, lower doses of alteplase are associated with significant sICH reduction and non-inferior performance in efficacy, compared with those in the standard dose group.

Trial registration number

The TIMS-China was a national prospective stroke registry on thrombolytic therapy using intravenous tPA in patients who had acute ischaemic stroke. The results were initially published in 2012 without a clinical trial registration number. The Shanghai Stroke Service System was registered at www.clinicaltrial.gov (NCT02735226).

The Impact of Tumor Necrosis Factor-α and Interleukin-1β Levels and Polymorphisms on Long-Term Stroke Outcomes

Background: The accuracy of predictions regarding disability that sets in after stroke could be improved by using blood biomarker measurements. This study aimed to investigate the roles of serum tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β concentrations and polymorphisms in stroke outcomes. Methods: In total, 286 patients were evaluated at the time of admission and at 2 weeks after stroke, and 222 of these patients (78%) were followed up for 1 year to evaluate the consequences of stroke during both the acute and chronic stages. Stroke outcomes were dichotomized into good and poor using the modified Rankin Scale. Results: The association of TNF-α and IL-1β concentrations and their corresponding genotypes with stroke outcomes was investigated using multivariate logistic regression. Higher TNF-α levels were associated with poor outcomes 1 year after stroke in the presence of the –850T and –308A alleles, and IL-1β levels were associated with poor 1-year stroke outcomes in the presence of the –511T and +3953T alleles. No such associations were found at 2 weeks after stroke. Conclusions: These data provide evidence that serum TNF-α and IL-1β concentrations are related to poor long-term outcomes after stroke in the presence of particular alleles.

The golden hour of acute ischemic stroke

Background

Acute Ischemic Stroke (AIS) treatment has been revolutionised in the last two decades with the increasing use of Intravenous Thrombolysis (IVT) and with the advent of Endovascular therapy (EVT). AIS treatment and outcome are time dependant and time saving measures are being implemented at every step of the treatment chain. These changes have resulted in lower treatment times in-hospital, but it is unclear if this translates into more patients being treated within 60 min of symptom onset – the Golden Hour. The clinical outcome of IVT therapy in this patient group was our secondary outcome.

Methods

From 2009 onwards, systematic changes were made to the AIS treatment chain leading to a dramatic decrease in Door-to-Needle (DTN) time. Analyses were performed on the number of these treatments year on year and their clinical outcomes within the Golden Hour at Stavanger University Hospital (SUS).

Results

Six-hundred and thirteen patients were included; seventy-three were treated within the Golden Hour. The percentage of total IVT treatments occurring in the Golden Hour rose from 2.2% in 2009 to 14.5% in 2015 (p = 0.006) with a high of 18.3% in 2012 (p < 0.001). All of these patients had a Median NIHSS of 0 at discharge, irrespective of age and pre-existing comorbidity. There was no incidence of any ICH and in-hospital mortality was only 2.7% in this group.

Discussion

The time from AIS symptom onset to treatment is filled with delays. Despite the inherence of some delays,significant efforts on the part of the pre- and in- hospital treatment chain have made IVT therapy within 60 min a possibility. The allocation and use of resources in the setting of rapid AIS treatment is warrantedand yields unprecedented results.

Conclusions

Our study shows that improved treatment routines led to an increase in the number of patients treated within the Golden Hour. Treatment in the Golden Hour leads to excellent outcomes in all patients, irrespective of age and pre-existing comorbidity.

Intra-Arterial vs Intra-Venous Thrombolysis for Anterior Cerebral Occlusion

Background:

The safety and effectiveness of intra-arterial thrombolysis (IAT) in comparison to intravenous thrombolysis (IVT) for the treatment of ischemic stroke is uncertain. Our study aims to assess and compare IAT to IVT for clinically relevant outcomes in patients with occlusion of the anterior cerebral circulation.

Methods:

Patients with acute ischemic stroke were enrolled for either treatment; those whose symptoms occurred within 4.5 hrs after stroke were treated with IVT, whereas those who presented <4.5 hrs but had contraindications to IVT or presented between 4.5 and 6 hrs were treated with IAT. Evaluated endpoints included: disability at 90 days as measured by the modified Rankin Scale (mRS), incidence of mortality, and incidence of symptomatic intracranial haemorrhage.

Results:

78 patients with anterior cerebral circulation occlusion were included in the study (55 in IVT, 23 in IAT). After 90 days, 82.6% patients treated with IAT reached independence in comparison to 56.4% in the IVT group (P=0.028, RR=2.66, 95% CI: 1.10-7.04). The incidence of all intracranial haemorrhages in the IAT and IVT groups respectively were 30.4% and 12.7% (P=0.103, RR=2.391, 95% CI: 0.946-6.047); symptomatic intracranial haemorrhage occurred in 8.7% and 9.1% of patients (P=1.00, RR= 0.957, 95% CI: 0.200-4.579), and mortality in 8.7% and 16.4% (P=0.492, RR=1.882, 95% CI: 0.440-8.045).

Conclusion:

Results suggest that IAT is more effective than IVT in allowing patients to achieve independence. While inconclusive, the safety of IAT within 6 hrs is comparable to IVT within 4.5 hrs.

Thrombolysis for acute ischaemic stroke

BACKGROUND

Most strokes are due to blockage of an artery in the brain by a blood clot. Prompt treatment with thrombolytic drugs can restore blood flow before major brain damage has occurred and improve recovery after stroke in some people. Thrombolytic drugs, however, can also cause serious bleeding in the brain, which can be fatal. One drug, recombinant tissue plasminogen activator (rt-PA), is licensed for use in selected patients within 4.5 hours of stroke in Europe and within three hours in the USA. There is an upper age limit of 80 years in some countries, and a limitation to mainly non-severe stroke in others. Forty per cent more data are available since this review was last updated in 2009.

OBJECTIVES

To determine whether, and in what circumstances, thrombolytic therapy might be an effective and safe treatment for acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched November 2013), MEDLINE (1966 to November 2013) and EMBASE (1980 to November 2013). We also handsearched conference proceedings and journals, searched reference lists and contacted pharmaceutical companies and trialists.

SELECTION CRITERIA

Randomised trials of any thrombolytic agent compared with control in people with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria, extracted data and assessed trial quality. We verified the extracted data with investigators of all major trials, obtaining additional unpublished data if available.

MAIN RESULTS

We included 27 trials, involving 10,187 participants, testing urokinase, streptokinase, rt-PA, recombinant pro-urokinase or desmoteplase. Four trials used intra-arterial administration, while the rest used the intravenous route. Most data come from trials that started treatment up to six hours after stroke. About 44% of the trials (about 70% of the participants) were testing intravenous rt-PA. In earlier studies very few of the participants (0.5%) were aged over 80 years; in this update, 16% of participants are over 80 years of age due to the inclusion of IST-3 (53% of participants in this trial were aged over 80 years). Trials published more recently utilised computerised randomisation, so there are less likely to be baseline imbalances than in previous versions of the review. More than 50% of trials fulfilled criteria for high-grade concealment; there were few losses to follow-up for the main outcomes.Thrombolytic therapy, mostly administered up to six hours after ischaemic stroke, significantly reduced the proportion of participants who were dead or dependent (modified Rankin 3 to 6) at three to six months after stroke (odds ratio (OR) 0.85, 95% confidence interval (CI) 0.78 to 0.93). Thrombolytic therapy increased the risk of symptomatic intracranial haemorrhage (OR 3.75, 95% CI 3.11 to 4.51), early death (OR 1.69, 95% CI 1.44 to 1.98; 13 trials, 7458 participants) and death by three to six months after stroke (OR 1.18, 95% CI 1.06 to 1.30). Early death after thrombolysis was mostly attributable to intracranial haemorrhage. Treatment within three hours of stroke was more effective in reducing death or dependency (OR 0.66, 95% CI 0.56 to 0.79) without any increase in death (OR 0.99, 95% CI 0.82 to 1.21; 11 trials, 2187 participants). There was heterogeneity between the trials. Contemporaneous antithrombotic drugs increased the risk of death. Trials testing rt-PA showed a significant reduction in death or dependency with treatment up to six hours (OR 0.84, 95% CI 0.77 to 0.93, P = 0.0006; 8 trials, 6729 participants) with significant heterogeneity; treatment within three hours was more beneficial (OR 0.65, 95% CI 0.54 to 0.80, P < 0.0001; 6 trials, 1779 participants) without heterogeneity. Participants aged over 80 years benefited equally to those aged under 80 years, particularly if treated within three hours of stroke.

AUTHORS' CONCLUSIONS

Thrombolytic therapy given up to six hours after stroke reduces the proportion of dead or dependent people. Those treated within the first three hours derive substantially more benefit than with later treatment. This overall benefit was apparent despite an increase in symptomatic intracranial haemorrhage, deaths at seven to 10 days, and deaths at final follow-up (except for trials testing rt-PA, which had no effect on death at final follow-up). Further trials are needed to identify the latest time window, whether people with mild stroke benefit from thrombolysis, to find ways of reducing symptomatic intracranial haemorrhage and deaths, and to identify the environment in which thrombolysis may best be given in routine practice.

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

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

Pharmacological therapies in post stroke recovery: recommendations for future clinical trials

Stroke is a leading cause of serious long-term disability in adults and is the second leading cause of death worldwide. Early reperfusion and neuroprotection techniques have been the focus of much effort with the aim of very acute treatment of the stroke. Targeting different mechanisms, pharmacological therapies have the potential to reduce disability in a large fraction of patients who survive the acute stroke. The brain's capacity to reorganize after stroke through plasticity mechanisms can be modulated by pharmacological agents. A number of therapeutic interventions are under study, including small molecules, growth factors, and monoclonal antibodies. Recently it has been shown that the SSRI fluoxetine improved motor deficit in patients with ischaemic stroke and hemiplegia which appeared to be independent of the presence of depression. In this context, it is of major importance to support innovative research in order to promote the emergence of new pharmacological treatments targeting neurological recovery after stroke, as opposed to acute de-occlusion and neuroprotection. This paper is the work of a group of 14 scientists with aim of (1) addressing key areas of the basic and clinical aspects of human brain plasticity after stroke and potential pharmacological targets for recovery, (2) asking questions about the most appropriate characteristics of clinical trials testing drugs in post stroke recovery and (3) proposing recommendations for future clinical trials.

Elderly patients and intra-arterial stroke therapy

Ischemic stroke disproportionately affects the elderly, particularly those over the age of 80 years. Rates of stroke are expected to increase over the next several decades due to increasing numbers of elderly individuals, making understanding stroke treatment in this population an imperative. The only proven acute stroke therapy is early reperfusion, accomplished through intravenous or intra-arterial means. Intra-arterial stroke therapy (IAT) offers higher recanalization rates than intravenous tissue plasminogen activator, but has yet to show clear superiority over intravenous tissue plasminogen activator alone. Existing data suggest that elderly stroke patients suffer worse outcomes following IAT, despite similar rates of recanalization and symptomatic intracranial hemorrhage. This article reviews the application of IAT in the elderly population and summarizes the available studies that investigate the response of elderly patients to IAT.

A very early neurological improvement after intravenous thrombolysis for acute cerebral ischaemia does not necessarily predict a favourable outcome

In patients treated by intravenous (i.v.) thrombolytic therapy for cerebral ischaemia, a very early neurological improvement (VENI) [National Institutes of Health Stroke Scale score (NIHSSS) 0, or early improvement ≥5 points], predicts a favourable outcome. VENI patients are usually excluded from trials testing complementary strategies, but a few of them have bad outcomes. To determine why VENI patients may have bad outcomes, we analysed the reasons for bad outcomes [modified Rankin Scale (mRS) score 2-6 at 3 months] in consecutive VENI patients. Of 365 consecutive patients with a pre-stroke mRS 0-1 (185 men, median age 69 years, median NIHSSS 12, median onset-to-needle time 147 min), 71 (19.5 %) had VENI. They were more likely to have had recent transient ischaemic attacks (OR 3.64, 95 % CI 1.08-12.27), higher baseline NIHSSS (median 14 vs. 11, p = 0.003) and shorter onset-to-needle times (median 135 min vs. 151, p = 0.01), and they were less likely to develop pneumonia (OR 0.27, 95 % CI 0.09-0.76) or malignant infarction (p = 0.045). In the 21 VENI patients (29.6 %) with a mRS 2-6 at 3-months, bad outcomes were due to the residual deficit in 14, secondary worsening of ischaemia in 4, intracranial haemorrhage in 2, and death from cancer in 1. One-third of VENI patients have bad outcomes, due to the residual neurological deficit in most of them. This finding suggests that VENI patients who still have a significant neurological deficit 1 h after thrombolysis should not be excluded from trials testing complementary strategies.

The iScore predicts efficacy and risk of bleeding in the National Institute of Neurological disorders and Stroke Tissue Plasminogen Activator Stroke Trial

The iScore is a validated tool to estimate outcomes after an acute ischemic stroke. A previous study showed the iScore can predict clinical response and risk of intracerebral hemorrhage (ICH) after administration of tissue plasminogen activator (tPA). We applied the iScore (www.sorcan.ca/iscore) to participants in the National Institute of Neurological Disorders and Stroke tPA stroke trials to evaluate its ability to estimate clinical response and risk of ICH after thrombolysis. Based on results from our previous study, patients were stratified a priori into iScore <200 and iScore ≥ 200. The main outcome measure was ICH. Secondary outcomes included favorable composite outcome (defined as a modified Rankin Scale score of 0 or 1, National Institutes of Health Stroke Scale score ≤ 1, Barthel Index ≥ 95, or Glasgow Outcome Scale <1 at 3 months) and functional outcomes. The iScore was calculated in all 624 patients enrolled in the trial. The cohort comprised 507 patients (81%) with an iScore <200 and 117 (19%) with an iScore ≥ 200. An iScore ≥ 200 was associated with greater risk of symptomatic ICH in the tPA group compared with the placebo group (15.4% v 3.9%; P = .04). Similar findings were found for ICH of any type (30.8% v 11.5%; P = .014), with higher ICH mortality (69.2% v 23.8%; P < .001). Despite the higher favorable composite outcome of tPA therapy in patients with an iScore <200 (58.7% v 41.9%; P < .001), this therapy had no benefit in patients with an iScore ≥ 200 (15.4% v 13.4%; P = .77). In patients receiving tPA in the National Institute of Neurological Disorders and Stroke trial, the iScore estimated the clinical response and risk of hemorrhagic complications. Further prospective studies are needed before a change in practice can be recommended.

Statistical analysis of the primary outcome in acute stroke trials

Common outcome scales in acute stroke trials are ordered categorical or pseudocontinuous in structure but most have been analyzed as binary measures. The use of fixed dichotomous analysis of ordered categorical outcomes after stroke (such as the modified Rankin Scale) is rarely the most statistically efficient approach and usually requires a larger sample size to demonstrate efficacy than other approaches. Preferred statistical approaches include sliding dichotomous, ordinal, or continuous analyses. Because there is no best approach that will work for all acute stroke trials, it is vital that studies are designed with a full understanding of the type of patients to be enrolled (in particular their case mix, which will be critically dependent on their age and severity), the potential mechanism by which the intervention works (ie, will it tend to move all patients somewhat, or some patients a lot, and is a common hazard present), a realistic assessment of the likely effect size, and therefore the necessary sample size, and an understanding of what the intervention will cost if implemented in clinical practice. If these approaches are followed, then the risk of missing useful treatment effects for acute stroke will diminish.

Medical therapy for ischemic stroke: review of intravenous and intra-arterial treatment options

BACKGROUND

Thrombolytic therapy is of proven and substantial benefit for select patients with acute cerebral ischemia. Diagnostic options and medical treatment options for acute stroke ischemia have undergone enormous changes in the past decades. Whereas initially stroke treatment was reduced to prevention, management of symptoms, and rehabilitation, nowadays a multitude of different fibrinolytic drugs are available. The wide availability of computed tomography in the late 1980s made thrombolysis a real therapeutic option because it allowed a fast and accurate differentiation between ischemic and hemorrhagic stroke.

METHODS

This study reviews these developments and how they have shaped our current use and understanding of thrombolytics in the treatment of acute ischemic stroke.

RESULTS

Patient selection remains a central aspect of thrombolytic treatment, and to date, the use of different fibrinolytics has been studied in over 20 large randomized trials for different clinical settings, time windows, and routes of administration. These studies included over 7000 patients, and led to our current understanding of the use of thrombolysis in acute stroke.

CONCLUSIONS

Intravenous fibrinolytic therapy within the first 3 hours of ischemic stroke onset offers substantial benefits for virtually all patients with potentially disabling deficits. In the 3- to 4.5-hour treatment window, intravenous fibrinolytic therapy has been shown to offer moderate net benefits when applied to all patients with potentially disabling deficits. Intra-arterial fibrinolytic therapy in the 3- to 6-hour window offers moderate net benefits when applied to all patients with potentially disabling deficits and large-artery cerebral thrombotic occlusions.

Impact of a combined intravenous/intra-arterial approach in octogenarians

BACKGROUND

Intravenous (IV) alteplase is not currently recommended in octogenarian patients, and the benefit/risk ratio of endovascular (intra-arterial, IA) therapy remains to be determined. The aim of this study was to determine the impact of a combined IV-IA approach in octogenarians.

METHODS

From a single-centre interventional study, we report age-specific outcomes of patients treated by a combined IV-IA thrombolytic approach. Patients ≥80 years with documented arterial occlusion treated by conventional IV thrombolysis constituted the control group.

RESULTS

Among 84 patients treated by the IV-IA approach, those ≥80 years (n = 25) had a similar rate of early neurological improvement to that of patients <80 years, whereas the 90-day favourable outcome rate was lower in octogenarians (adjusted odds ratio, OR, 0.21; 95% confidence interval, CI, 0.06-0.75). No difference in symptomatic intracranial haemorrhage was observed whereas a higher rate of 90-day mortality (adjusted OR, 3.27; 95% CI, 0.76-14.14) and asymptomatic intracranial haemorrhage (adjusted OR, 6.39; 95% CI, 1.54-26.63) were found in patients ≥80 years old. Among octogenarians, and compared to IV-thrombolysis-treated patients (n = 24), patients treated by the IV-IA approach had a higher rate of recanalization (76 vs. 33%, p = 0.003) associated with increased early neurological improvement (32 vs. 8%, p = 0.07). Although there was a higher rate of asymptomatic intracranial haemorrhage (44 vs. 8%, p = 0.005) observed in the IV-IA group, no difference existed in symptomatic intracranial haemorrhage rates and 90-day favourable outcome.

CONCLUSION

The IV-IA approach in octogenarians was associated with lower efficacy at 3 months and higher mortality and asymptomatic haemorrhagic complications than in patients <80 years old. Definite recommendations cannot be given, but an endovascular approach may cause more harm than positive effects in patients over 80 years and should not be considered outside an approved protocol.

Thrombolysis for acute ischaemic stroke

BACKGROUND

The majority of strokes are due to blockage of an artery in the brain by a blood clot. Prompt treatment with thrombolytic drugs can restore blood flow before major brain damage has occurred and could improve recovery after stroke. Thrombolytic drugs, however, can also cause serious bleeding in the brain, which can be fatal. One drug, recombinant tissue plasminogen activator (rt-PA), is licensed for use in highly selected patients within three hours of stroke.

OBJECTIVES

To assess the safety and efficacy of thrombolytic agents in patients with acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched October 2008), MEDLINE (1966 to October 2008) and EMBASE (1980 to October 2008). We contacted researchers and pharmaceutical companies, attended relevant conferences and handsearched pertinent journals.

SELECTION CRITERIA

Randomised trials of any thrombolytic agent compared with control in patients with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria and extracted data. We assessed trial quality. We verified the extracted data with the principal investigators of all major trials. We obtained both published and unpublished data if available.

MAIN RESULTS

We included 26 trials involving 7152 patients. Not all trials contributed data to each outcome. The trials tested urokinase, streptokinase, recombinant tissue plasminogen activator, recombinant pro-urokinase or desmoteplase. Four trials used intra-arterial administration, the rest used the intravenous route. Most data come from trials that started treatment up to six hours after stroke; three trials started treatment up to nine hours and one small trial up to 24 hours after stroke. About 55% of the data (patients and trials) come from trials testing intravenous tissue plasminogen activator. Very few of the patients (0.5%) were aged over 80 years. Many trials had some imbalances in key prognostic variables. Several trials did not have complete blinding of outcome assessment. Thrombolytic therapy, mostly administered up to six hours after ischaemic stroke, significantly reduced the proportion of patients who were dead or dependent (modified Rankin 3 to 6) at three to six months after stroke (odds ratio (OR) 0.81, 95% confidence interval (CI) 0.73 to 0.90). Thrombolytic therapy increased the risk of symptomatic intracranial haemorrhage (OR 3.49, 95% CI 2.81 to 4.33) and death by three to six months after stroke (OR 1.31, 95% CI 1.14 to 1.50). Treatment within three hours of stroke appeared more effective in reducing death or dependency (OR 0.71, 95% CI 0.52 to 0.96) with no statistically significant adverse effect on death (OR 1.13, 95% CI 0.86 to 1.48). There was heterogeneity between the trials in part attributable to concomitant antithrombotic drug use (P = 0.02), stroke severity and time to treatment. Antithrombotic drugs given soon after thrombolysis may increase the risk of death.

AUTHORS' CONCLUSIONS

Overall, thrombolytic therapy appears to result in a significant net reduction in the proportion of patients dead or dependent in activities of daily living. This overall benefit was apparent despite an increase both in deaths (evident at seven to 10 days and at final follow up) and in symptomatic intracranial haemorrhages. Further trials are needed to identify which patients are most likely to benefit from treatment and the environment in which thrombolysis may best be given in routine practice.

Evaluation of a sequential global test of improved recovery following stroke as applied to the ICTUS trial of citicoline

The International Citicoline Trial in acUte Stroke is a sequential phase III study of the use of the drug citicoline in the treatment of acute ischaemic stroke, which was initiated in 2006 in 56 treatment centres. The primary objective of the trial is to demonstrate improved recovery of patients randomized to citicoline relative to those randomized to placebo after 12 weeks of follow-up. The primary analysis will take the form of a global test combining the dichotomized results of assessments on three well-established scales: the Barthel Index, the modified Rankin scale and the National Institutes of Health Stroke Scale. This approach was previously used in the analysis of the influential National Institute of Neurological Disorders and Stroke trial of recombinant tissue plasminogen activator in stroke.The purpose of this paper is to describe how this trial was designed, and in particular how the simultaneous objectives of taking into account three assessment scales, performing a series of interim analyses and conducting treatment allocation and adjusting the analyses to account for prognostic factors, including more than 50 treatment centres, were addressed.

Relationship of neurovascular elements to neuron injury during ischemia

Occlusion of flow to the brain regions identifies regions of vulnerability within the vascular territory at risk, which coalesce to become the mature ischemic lesion. A large number of unsuccessful clinical trials have focused on neuron and extravascular targets in humans that have shown apparent salvage in preclinical models. However, the observation that microvessel and neuron responses to ischemia occur simultaneously in these regions suggest that the responses could be coordinated. This presentation examines evidence in support of the conceptual 'neurovascular unit' and its application to the setting of acute intervention trials in ischemic stroke. There are no uniform reasons for which nonvascular interventions, as a class, have not been successful in clinical trials, but both the clinical observations and the hypothesis imply the need to understand interactions with the neurovascular unit as a prelude to further neuron protectant trials.

[Intravenous thrombolysis with rt-PA in stroke: experience of the Nice stroke unit]

INTRODUCTION

Intravenous thrombolysis with rt-Pa in stroke has been approved in France since 2002. We report an evaluation of our practice. We have tried to identify predictive factors of dependence and death, and to compare our results with the data of the literature.

PATIENTS AND METHOD

All patients treated with intravenous rt-PA within the first 270min after the stroke onset were included. Univariate, then multivariate analyses were performed to determine the variables influencing the functional outcome at 3 months follow-up, according to a dichotomy established from the modified Rankin scale.

RESULTS

One hundred and forty-two patients were included in this study (mean initial National Institute of Health Stroke Scale [NIHSS]: 15). Fifty percent had a Rankin score higher than 2 at 3 months follow-up. NIHSS above 12, glycemia of at least 120mg/l, and systolic blood pressure above 160mmHg at admission were identified as independent predictive factors of poor functional outcome. Less than 4 points decrease of NIHSS proved to be a simple and early predictor of poor functional outcome at 3 months follow-up.

CONCLUSIONS

In terms of safety and efficacy the data issuing from the daily activity of our stroke unit are comparable with those of clinical trials.

Tissue plasminogen activator use: evaluation and initial management of ischemic stroke from an Iowa hospital perspective

Despite its efficacy for acute ischemic stroke, tissue plasminogen activator (rt-PA) is reported as used in less than 5% of patients with stroke. This study assessed the rate of intravenous rt-PA use in a community hospital and identified factors influencing rt-PA use. A retrospective chart review revealed a total of 464 patients presenting to the emergency department with a primary diagnosis of stroke from January 2000 through June 2002. Records were sorted into 3 groups: those presenting to the emergency department within 3 hours, 3 to 6 hours, and 6 hours or more of symptom onset. Each record was reviewed using National Institute of Neurologic Disorders and Stroke thrombolytic therapy criteria. Primary measures were rate of intravenous rt-PA use and reasons for not receiving rt-PA. Of the 464 patients with stroke who presented to the emergency department during the 30-month period, 99 arrived in less than 3 hours, 22 between 3 and 6 hours, and 343 greater than 6 hours. A total of 13 (2.8% of all patients with stroke or 13% of those presenting within 3 hours) received rt-PA. All patients meeting criteria received rt-PA. Rapidly improving or minor symptoms and difficult to control or elevated blood pressure were the most common reasons for not using rt-PA. Of the patients arriving within the 3-hour window, 14 were excluded by time factors. We conclude from this study that rt-PA can be effectively used in community hospitals and that use likely exceeds previously quoted national rates when based on a more appropriate measure of eligibility criteria as opposed to total presenting patients with stroke.

What should be defined as good outcome in stroke trials; a modified Rankin score of 0-1 or 0-2?

BACKGROUND AND PURPOSE

Good outcome in stroke trials has been defined as a modified Rankin scale (mRs) score of 0-1 or 0-2. The aim of this study was to investigate the clinical meaning of these two dichotomies.

METHODS

We studied 152 patients six months post stroke using the mRs and a new disability measure the AMC Linear Disability Scale (ALDS) item bank. Descriptive statistics were used to show the ALDS scores by the levels of the mRs. To investigate the clinical meaning of the different definitions of good outcome, the mean probability to perform activities of daily life (ADL) of all mRs grades and these two dichotomies was calculated.

RESULTS

The ability to perform difficult ALDS items declined gradually with increasing mRs grade. When favourable outcome is defined as mRs 0-1, 15 % of the cohort has a good outcome; of these patients 84 % were likely to perform outdoor activities. If good outcome is defined as mRs 0-2, the percentage of patients with good outcome increased to 37 %, whereas 66 % of these patients were likely to perform outdoor activities.

CONCLUSION

If good outcome is defined as the ability to perform outdoor activities mRs 0-1 should be chosen. If complex ADL are considered as good outcome mRs 0-2 is the outcome measure of choice. Independent of which outcome measure is chosen, the treatment effect in clinical trials must be large before good outcome is achieved. Therefore, it is likely that clinically important treatment effects can be missed in clinical trials with both these mRs endpoints.

Utilisation du rt-PA intraveineux dans l’ischémie cérébrale en Centre Hospitalier Général : l’expérience de l’Hôpital Saint-Jean de Perpignan

INTRODUCTION

Intravenous recombinant tissue plasminogen activator (rt-PA) has approval for use despite of its authorization for treatment of ischemic stroke within the 3-hour time window in 2003, is rarely used in community hospital (CH). It therefore remains questionable if the positive results of the key studies conducted in specialized centers may be extended to community hospitals less specialized in the management of stroke.

METHODS

We report the results of an observational cohort study including 39 patients treated with intravenous rt-Pa (according to the NINDS rt-PA stroke trail treatment protocol) at St Jean Hospital (Perpignan, France) between March 1, 2002 and August 31, 2005. Results are compared to those of the treated arm of the NINDS study.

RESULTS

1.2p.cent of ischemic stroke were treated with intravenous rt-Pa. Results are similar to those of the NINDS study: The outcome was favorable (modified Rankin score (mRS) with 0 or 1) for 44p.cent of the patients (as compared to 39p.cent in the NINDS study (X2 = 0.34; p = 0.5)) and there was no significant difference in term of death or outcome as assessed by mRS at 3 months (X2 = 0.09; p = 0.75 and X2 = 0.77; p = 0.75, respectively). No symptomatic hemmorrhagic transformation related to the use of rt-Pa was observed.

CONCLUSION

Our results indicate that rt-PA therapy for ischemic stroke may be as safe and effective in the setting of a community hospital as it is in specialized centers.

Thrombolytic therapy for acute ischemic stroke: 3 h and beyond

The current status of thrombolytic therapy approved by the US Food and Drug Administration is intravenous recombinant plasminogen activator given within 3 h of the onset of ischemic stroke. Intra-arterial therapy is possible for up to 6 h but is not Food and Drug Administration-approved for this purpose. Based on current radiologic methods (i.e., magnetic resonance imaging and perfusion computed tomography scans), it is being increasingly realized that the time window for effective thrombolytic therapy is variable, and salvageable tissue in the form of the ischemic penumbra may exist for longer periods of time and could therefore offer a greater time window based on these imaging studies. Development of an effective neuroprotective drug would greatly enhance the stability of the penumbra and offer further opportunities for extending the time window for reperfusion.

Critical Appraisal and Review of the Rankin Scale and Its Derivatives

BACKGROUND AND PURPOSE

Efforts to reduce stroke burden require accurate assessment of outcomes in order to compare treatments. The Rankin Scale and its derivatives, the Modified Rankin Scale and the Oxford Handicap Scale, taken together, are among the most common outcome measures that have been used in stroke research. The aim of this study was to perform a critical appraisal of the clinimetric properties of these scales. It was also planned to review the use of these scales in a selection of articles to illustrate concerns raised by the critical appraisal.

SUMMARY OF REVIEW

A literature search was performed using electronic databases to locate relevant articles about the reviewed scales. The scales were appraised using a structured format regarding the following properties: purpose, development, presentation, language, method of administration, content validity, face validity, feasibility, construct validity, reliability, responsiveness, and generalizability. There are concerns in each of the appraised areas regarding the clinimetric properties of these scales.

CONCLUSION

Further work is needed to improve the clinimetric properties of the reviewed scales to ensure that they are more useful tools in determining the outcome of stroke. Alternatively, a newer global outcome scale with improved clinimetric properties may be a better option for future stroke research.

Outcome measures for clinical research in sepsis: a report of the 2nd Cambridge Colloquium of the International Sepsis Forum

BACKGROUND AND OBJECTIVES

Sepsis is the leading cause of morbidity and mortality for patients admitted to an intensive care unit. The evaluation of new therapies has been hampered by the underdevelopment of outcome measures used to detect biological activity and patient-centered benefit in a complex and highly heterogeneous patient population. We sought to evaluate existing approaches and to draw on insights from other disciplines to propose a comprehensive approach to outcome evaluation in sepsis clinical trials.

METHODS

An expert colloquium organized by the International Sepsis Forum brought together sepsis researchers, clinical epidemiologists, and experts in the development and implementation of outcome measures in rheumatology, neurology, and oncology.

RESULTS

The translation of an evolving understanding of the biology of sepsis into effective new therapies for critically ill patients requires a reevaluation of the end points used to determine response to intervention. These represent a continuum that measures biological activity against the target at one end and sustained improvement in survival or quality of life at the other. Early phase research should determine whether an intervention works in vivo, using measures that are responsive and informative to provide proof of principle, to aid in selecting optimal patient populations for study, and to gain insights into optimal dose and duration of therapy. After in vivo biology has been demonstrated and the possibility of efficacy inferred by plausible improvements in surrogate physiologic measures, definitive studies should seek robust evidence of benefit using end points that measure important, patient-centered benefit, including intermediate and longer term survival and health-related quality of life. Nonmortal measures of benefit assume particular importance for populations, such as children, whose mortality risk is low, or who have significant rates of comorbidities that independently limit survival. Composite measures that integrate morbidity and mortality effects may provide the most meaningful information about therapeutic efficacy.

CONCLUSIONS

The development of explicit, hypothesis-driven, and iterative approaches to outcome measure development, patterned on approaches used in the fields of rheumatology and oncology, may improve the conduct of clinical studies in the critically ill.

Intravenous Thrombolysis for Acute Ischemic Stroke

Intravenous recombinant tissue-type plasminogen activator (rtPA, alteplase) is the only drug approved for the treatment of acute ischemic stroke. It should be administered within 3 hours of stroke. There is additional evidence, however, that administration at later times, by means of other methods, is effective. Herein, is a broad review of the knowledge gained and insights created from studies in which thrombolytic treatment was used in patients with stroke.

Thrombolysis for acute ischaemic stroke

BACKGROUND

The majority of strokes are due to blockage of an artery in the brain by a blood clot. Prompt treatment with thrombolytic drugs can restore blood flow before major brain damage has occurred. Successful treatment could mean that the patient is more likely to make a good recovery from their stroke. Thrombolytic drugs however, can also cause serious bleeding in the brain which can be fatal. Thrombolytic therapy has now been evaluated in several randomised trials in acute ischaemic stroke.

OBJECTIVES

The objective of this review was to assess the safety and efficacy of thrombolytic agents in patients with acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched January 2003), MEDLINE (1966- January 2003) and EMBASE (1980-January 2003). In addition we contacted researchers and pharmaceutical companies, attended relevant conferences and handsearched four Japanese journals.

SELECTION CRITERIA

Randomised trials of any thrombolytic agent compared with control in patients with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed. The extracted data were verified by the principal investigators of all major trials. Thus published and unpublished data were obtained where available.

MAIN RESULTS

Eighteen trials including 5727 patients were included, but not all trials contributed data to each outcome examined in this review. Sixteen trials were double-blind. The trials tested urokinase, streptokinase, recombinant tissue plasminogen activator or recombinant pro-urokinase. Two trials used intra-arterial administration but the rest used the intravenous route. About 50% of the data (patients and trials) come from trials testing intravenous tissue plasminogen activator. There are few data from patients aged over 80 years. Much of the data comes from trials conducted in the first half of the 1990s when, in an effort to reduce delays to trial drug administration, on site randomisation methods were used that, in consequence, limited the ability to stratify randomisation on key prognostic variables. Several trials, because of the biological effects of thrombolysis combined with the follow-up methods used, did not have complete blinding of outcome assessment. Thrombolytic therapy, administered up to six hours after ischaemic stroke, significantly reduced the proportion of patients who were dead or dependent (modified Rankin 3 to 6) at the end of follow-up at three to six months (OR 0.84, 95% CI 0.75 to 0.95). This was in spite of a significant increase in : the odds of death within the first ten days (odds ratio [OR] 1.81, 95% confidence interval [CI] 1.46 to 2.24), the main cause of which was fatal intracranial haemorrhage (OR 4.34, 95% CI 3.14 to 5.99). Symptomatic intracranial haemorrhage was increased following thrombolysis (OR 3.37, 95% CI 2.68 to 4.22). Thrombolytic therapy also increased the odds of death at the end of follow-up at three to six months (OR 1.33, 95% CI 1.15 to 1.53). For patients treated within three hours of stroke, thrombolytic therapy appeared more effective in reducing death or dependency (OR 0.66, 95% CI 0.53 to 0.83) with no statistically significant adverse effect on death (OR 1.13, 95% CI 0.86 to 1.48). There was heterogeneity between the trials that could have been due to many trial features including : thrombolytic drug used, variation in the use of aspirin and heparin, severity of the stroke (both between trials and between treatment groups within trials), and time to treatment. Trials testing intravenous recombinant tissue plasminogen activator suggested that it may be associated with slightly less hazard and more benefit than other drugs when given up to six hours after stroke but these are non-random comparisons - death within the first ten days OR 1.24, 95% CI 0.85 to 1.81, death at the end of follow-up OR 1.17, 95% CI 0.95 to 1.45, dead or dependent at the end of follow-up OR 0.80, 95% CI 0.69 to 0.93. However, no trial has directly comparedup OR 0.80, 95% CI 0.69 to 0.93. However, no trial has directly compared rt-PA with any other thrombolytic agent. There is some evidence that antithrombotic drugs given soon after thrombolysis may increase the risk of death.

REVIEWER'S CONCLUSIONS

Overall, thrombolytic therapy appears to result in a significant net reduction in the proportion of patients dead or dependent in activities of daily living. However, this appears to be net of an increase in deaths within the first seven to ten days, symptomatic intracranial haemorrhage, and deaths at follow-up at three to six months. The data from trials using intravenous recombinant tissue plasminogen activator, from which there are the most evidence on thrombolytic therapy so far, suggest that it may be associated with less hazard and more benefit. There was heterogeneity between the trials for some outcomes and the optimum criteria to identify the patients most likely to benefit and least likely to be harmed, the latest time window, the agent, dose, and route of administration, are not clear. The data are promising and may justify the use of thrombolytic therapy with intravenous recombinant tissue plasminogen activator in experienced centres in highly selected patients where a licence exists. However, the data do not support the widespread use of thrombolytic therapy in routine clinical practice at this time, but suggest that further trials are needed to identify which patients are most likely to benefit from treatment and the environment in which it may best be given. To avoid the problem of data missing from some trials for some key outcomes encountered in this review to date, and to assist future metaanalyses, future trialists should try to collect data in such a way as to be compatible with the basic outcome assessments reviewed here (eg early death, fatal intracranial haemorrhage, poor functional outcome).

Development of thrombolytic therapy for stroke: a perspective

Thrombolysis with tissue plasminogen activator (alteplase, Activase trade mark, rtPA; Genentech Inc) has proven beneficial for acute stroke management, even though only 1 - 2% of stroke patients in the US are treated with the drug [1]. Part of the reason for the under utilisation of alteplase may be the narrow therapeutic window and frequent occurrence of serious side effects, such as increased haemorrhage incidence [2,3]. It is because of these shortcomings, that recent efforts have attempted to identify new thrombolytics that might improve the benefit/risk ratio in treating stroke. Second generation derivatives of alteplase have attempted to counteract the side effects of the drug by increasing fibrin specificity (tenecteplase, TNK-tPA; Genentech Inc) or half-life (lanoteplase, SUN-9216; Genetics Institute Inc.). New recombinant DNA methodology has led to the revival of plasmin or a truncated form of plasmin (microplasmin; ThromboGenics Ltd), a direct-acting thrombolytic with non-thrombolytic related neuroprotective activities, as a therapeutic. Other promising approaches for the treatment of stroke include the development of novel plasminogen activators, such as recombinant desmodus rotundus salivary plasminogen activator (rDSPA) alpha-1 (Schering/Teijin Pharmaceuticals) and a mutant fibrin-activated human plasminogen (BB10153; British Biotech Inc.). These important areas of drug discovery and development will be reviewed.

Thrombolysis in stroke

The ability to use an effective treatment constitutes a main concern in the management of acute ischemic stroke. Randomized trials have so far failed to demonstrate any beneficial effect of neuroprotective agents on neurologic outcome after an acute stroke. Thrombolytic agents can achieve early recanalization of an occluded intracerebral artery. The benefit of their use in ischemic stroke has been assessed in several randomized trials involving more than 5,000 patients. Among them, a single randomized trial, the National Institute of Neurological Diseases and Stroke Trial, showed a beneficial effect of thrombolysis on outcome after an acute ischemic stroke with a significant increase in the number of patients with no or minimal disability at 3 months in the group receiving intravenous recombinant tissue plasminogen activator (rt-PA) compared with placebo. However, there was no reduction in mortality and there was, as in all other trials, a significant increase in the risk of symptomatic intracerebral hemorrhage (ICH).

Optimal timing of thrombolytic therapy in acute ischaemic stroke

The clinical benefit of thrombolytic therapy for patients experiencing acute cerebral ischaemia has been demonstrated by both clinical trials and phase IV studies. However, such treatments must be initiated in a rapid manner, with treating physicians adhering to strict protocols designed to minimise delays and maximise safety. The efficacy of intravenous drug administration has been established with alteplase (recombinant tissue plasminogen activator; tPA) and ancrod, but only if these drugs can be administered within 3 hours of symptom onset. The use of alteplase beyond this timeframe, or outside of established protocols, may be hazardous. The use of alternative intravenous thrombolytic agents, such as streptokinase, also appears hazardous. Intra-arterial delivery of thrombolytic drugs such as pro-urokinase may extend clinical benefit to the 6-hour time frame.

Expression of P-selectin and intercellular adhesion molecule-1 in human brain after focal infarction or cardiac arrest

Data from experimental studies indicate that acute inflammation contributes to ischaemic brain damage. Tethering of neutrophils to brain endothelium is mediated by selectins, and subsequent adhesion and migration by endothelial intercellular adhesion molecule-1 (ICAM-1) and neutrophil CD18. In experimental studies of ischaemia-reperfusion injury, brain damage has been ameliorated by administration of antibodies to these adhesion molecules. We studied the expression of P-selectin and ICAM-1 in sections of brain from patients who had experienced cardiac arrest or focal brain infarction, and who died 3.5 h to 9 days later. Endothelial immunopositivity for both adhesion molecules was maximal at about 2-3 days then declined. Between 1 day and 3 days, P-selectin was also detected on platelets in blood vessels within infarcted tissue. Within infarcts, but not sections of brain from cardiac arrest patients, P-selectin and ICAM-1 were again detectable at 1 week, when hyperplastic endothelial cells were labelled in capillaries in and immediately adjacent to the infarcted tissue. The finding that P-selectin and ICAM-1 are upregulated within focally infarcted brain tissue supports the concept that blocking neutrophil adhesion may be of benefit in treating atherothrombotic strokes in man.

Can differences in management processes explain different outcomes between stroke unit and stroke-team care?

BACKGROUND

Stroke units reduce mortality and dependence, but the reasons are unclear. We have compared differences in management and complications of patients with acute stroke who were admitted to a stroke unit or to a general ward as part of a previously reported randomised trial.

METHODS

304 patients had been randomly assigned to stroke units (n=152) or to general wards supported by a specialist stroke team (152). We used a structured format to gather prospective data on the frequency of prespecified interventions in each of the major aspects of stroke care. Observations were undertaken daily for the first week and every week for the next 3 months by independent observers. The effect of differences in management on outcome at 3 months was assessed with the modified Rankin score, dichotomised to good (0-3) and poor (4-6) outcome.

FINDINGS

Patients in the stroke unit were monitored more frequently (odds ratio 2.1 [1.3-3.4]) and more patients received oxygen (2.0 [1.3-3.2]), antipyretics (6.4 [1.5-27.5]), measures to reduce aspiration (6.0 [2.3-15.5]), and early nutrition (14.4 [5.1-40.9]) than those in general wards. Complications were less frequent in patients in the stroke unit than those in general wards (0.6 [0.2-0.7]), with fewer patients having progression of stroke, chest infection, or dehydration. Measures to prevent aspiration, early feeding, stroke unit management, and frequency of complications independently affected outcome.

INTERPRETATION

Differences in management and complications between the stroke unit and general wards differ substantially, even when specialist support is provided. Such differences could be responsible for the more favourable outcome seen in patients on stroke units than those on general wards.

Alteplase: descendancy in myocardial infarction, ascendancy in stroke

Tissue type plasminogen activator is available, through recombinant technology, for thrombolytic use as alteplase. Alteplase is relatively clot specific and should cause less bleeding side effects than the non-specific agents such as streptokinase. Alteplase has been used successfully in evolving myocardial infarction (MI) to reopen occluded coronary arteries. It is probably equally effective or superior to streptokinase in opening arteries and reducing mortality in MI. Alteplase is most effective when given early in MI and is probably ineffective when given 12 h after the onset of symptoms. The effectiveness of alteplase in MI can be increased by front loading with a bolus of 15 mg, followed by an infusion of 50 mg over 30 min and 35 mg over 60 min. Percutaneous transluminal coronary angioplasty or stenting is associated with a greater patency and lower rates of serious bleeding, recurrent ischaemia and death than alteplase in MI and is likely to take over from alteplase as the standard MI treatment. A reduced dose of alteplase to increase coronary artery patency prior to angioplasty may be useful in MI. An exciting new indication for the use of alteplase is in stroke, where it has become the first beneficial intervention. Alteplase is used to reopen occluded cerebral vessels but is associated with an increased risk of intracerebral haemorrhage. Alteplase is beneficial if given within 3 h of the onset of stroke but not after this time period. Therefore, the next challenge is to increase the percentage of people being diagnosed and treated within this period. Clinical trials have not established a role for alteplase in the treatment of acute coronary syndromes or deep vein thrombosis. However, alteplase is useful in treating pulmonary thromboembolism and peripheral vascular disease.

Controversies about tissue plasminogen activator: extending the window of therapy

The management of stroke has undergone significant development over the past 15 years. Perhaps the single most important landmark has been the approval by the Food and Drug Administration of intravenous (IV) tissue plasminogen activator (t-PA) for the treatment of ischemic stroke. However, the approval of this drug has not met with unanimous support by the medical community and, at present, only a minority of stroke patients receive t-PA. Although this is partly due to the fact that many patients do not meet criteria for treatment with IV t-PA, others simply do not arrive at medical facilities sufficiently early to be safely managed using thrombolysis. The appropriate use of IV t-PA in the treatment of ischemic stroke requires proper selection of patients and strict adherence to clinical protocols of treatment. The ideal stroke patient for treatment with IV t-PA is one who suffers occlusion of a small artery that leads to a disabling deficit.

Understanding and managing ischemic stroke

Transient or permanent focal brain injury following acute thromboembolic occlusion develops from a complex cascade of pathophysiological events. The processes of excitotoxicity, peri-infarct depolarisation, inflammation, and apoptosis within the ischemic penumbra are proposed. While the translation of therapeutic agents from the animal models to human clinical trials have been disappointing, there remains an atmosphere of optimism as a result of the development of new diagnostic and therapeutic approaches, which include physiological, as opposed to pharmacological, intervention. This article provides an insight into the understanding of cerebral ischemia, together with current and future treatment strategies.Key words: cerebral ischemia, stroke, pathophysiology.