European Cooperative Acute Stroke Study (ECASS): (rt-PA-Thrombolysis in acute stroke) study design and progress report

Ischemic Stroke in the Cardiac Surgery Intensive Care Unit: A Quality Improvement Study

OBJECTIVE

To investigate the frequency of stroke and code stroke activation and the factors influencing code stroke management in postoperative cardiac surgical patients.

DESIGN

A retrospective quality improvement study was conducted between January 1, 2016, and December 31, 2021.

SETTING

The Cardiac Surgery Recovery Unit (CSRU) at London Health Sciences Centre in London, Ontario, Canada.

PARTICIPANTS

Postcardiac surgery patients aged 18 years or older who developed ischemic stroke during their admission to the CSRU.

INTERVENTIONS

No specific interventions were administered as part of this study. Code stroke activation mobilizes a specialized team. The objectives include assessment by a physician within 10 minutes, obtaining neuroimaging and interpretation within 45 minutes, and beginning treatment within 60 minutes.

MEASUREMENTS AND MAIN RESULTS

The incidence rate of stroke in the CSRU was 1.3%, and 34% of these patients had code stroke activated. The time since the last known well status was 11 ± 8 hours. The most common reasons for not activating code stroke were not meeting both timing and clinical criteria. The average time for computed tomography (CT) scan was 36 ± 22 minutes. Among patients who had code stroke activated, 24% had large- vessel occlusion (LVO), and 67% of those with LVO had an established stroke on their initial CT.

CONCLUSION

Code stroke was activated in only one-third of patients who experienced a stroke following cardiac surgery. Additionally, out of those who had code stroke activated, only one-fourth were diagnosed with LVO. Among those with LVO, two-thirds were found to have a well-established stroke on noncontrast CT scans and were deemed ineligible for intervention.

Ion Dyshomeostasis in the Early Hyperacute Phase after a Temporary Large-Vessel Occlusion Stroke

Element dysregulation is a pathophysiologic hallmark of ischemic stroke. Prior characterization of post-stroke element dysregulation in the photothrombotic model demonstrated significant element changes for ions that are essential for the function of the neurovascular unit. To characterize the dynamic changes during the early hyperacute phase (<6 h), we employed a temporary large-vessel occlusion stroke model. The middle cerebral artery was temporarily occluded for 30 min in male C57BL/6 mice, and coronal brain sections were prepared for histology and X-ray fluorescence microscopy from 5 to 120 min post-reperfusion. Ion dysregulation was already apparent by 5 min post-reperfusion, evidenced by reduced total potassium in the lesion. Later time points showed further dysregulation of phosphorus, calcium, copper, and zinc. By 60 min post-reperfusion, the central portion of the lesion showed pronounced element dysregulation and could be differentiated from a surrounding region of moderate dysregulation. Despite reperfusion, the lesion continued to expand dynamically with increasing severity of element dysregulation throughout the time course. Given that the earliest time point investigated already demonstrated signs of ion disruption, we anticipate such changes may be detectable even earlier. The profound ion dysregulation at the tissue level after reperfusion may contribute to hindering treatments aimed at functional recovery of the neurovascular unit.

Posterior circulation cerebral infarction: A review of clinical, imaging features, management, and outcomes

Objective

This narrative review discusses posterior circulation cerebral infarcts (PCCI) and provides an update given recent randomized trials in the management of basilar artery occlusion (BAO). We examine clinical characteristics, imaging protocols, management updates, and outcomes of PCCI.

Methods

The following databases were searched: MEDLINE, Scopus, Google Scholar, and Web of Science for articles on PCCI. We included randomized trials and observational studies in humans. We also reviewed relevant references from the literature identified.

Results

PCCI and BAO is associated with high morbidity and mortality. Early assessment and accurate diagnosis of PCCI remains a clinical challenge. Neuroimaging advances have improved early detection, but barriers remain due to costs and availability. Recent randomized trials provide new insights for BAO patients and support the efficacy of endovascular thrombectomy.

Discussion

PCCI requires specific diagnostic and management that is distinct from anterior circulation stroke. While further studies are needed in varied populations and in the subset of BAO patients presenting with milder deficits, growing randomized data support the treatment of BAO patients with endovascular thrombectomy.

Tenecteplase, 0.4 mg/kg, in Moderate and Severe Acute Ischemic Stroke: A Pooled Analysis of NOR-TEST and NOR-TEST 2A

Background The optimal dose of tenecteplase in acute ischemic stroke remains to be defined. We present a pooled analysis of the 2 NOR-TESTs (Norwegian Tenecteplase Stroke Trials) exploring the efficacy and safety of tenecteplase, 0.4 mg/kg. Methods and Results We retrospectively reviewed 2 PROBE (Prospective Randomized Open, Blinded End-point) trials, NOR-TEST and NOR-TEST 2A. Patients were randomized to either tenecteplase, 0.4 mg/kg, or alteplase, 0.9 mg/kg. The primary end point was favorable functional outcome at 3 months (modified Rankin Scale score, 0-1) or return to baseline if prestroke modified Rankin Scale score was 2. Secondary end points included favorable functional and clinical outcome and safety data. The pooled analysis includes patients with National Institutes of Health Stroke Scale score ≥6 from both trials and an additional post hoc analysis of patients with National Institutes of Health Stroke Scale score ≤5 from NOR-TEST. The per-protocol analysis contains 483 patients, of whom 235 were assigned to tenecteplase and 248 were assigned to alteplase. In per-protocol analysis, functional outcome was better in the alteplase arm with cutoff modified Rankin Scale score of 2 (odds ratio [OR], 0.52 [95% CI, 0.33-0.80]; P=0.003) and expressed by ordinal shift analysis (OR, 1.64 [95% CI, 1.17-2.28]; P=0.004). Mortality at 3 months was higher in the tenecteplase arm (OR, 2.48 [95% CI, 1.20-5.10]; P=0.01). Mortality and intracranial hemorrhage rates were higher in the severe stroke group randomized to tenecteplase, whereas these rates were similar for alteplase and tenecteplase in moderate and mild stroke. Conclusions Tenecteplase, 0.4 mg/kg, is unsafe in moderate and severe stroke, and the risk of death and intracranial hemorrhage probably increases with stroke severity. A lower tenecteplase dose should be tested in future trials. Registration URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01949948, NCT03854500.

Predictors of 30-day mortality among patients with stroke admitted at a tertiary teaching hospital in Northwestern Tanzania: A prospective cohort study

Background

Stroke is the second leading cause of death worldwide, with the highest mortality rates in low- to middle-income countries, particularly in sub-Saharan Africa. We aimed to investigate the predictors of 30-day mortality among patients with stroke admitted at a tertiary teaching hospital in Northwestern Tanzania.

Methods

This cohort study recruited patients with the World Health Organization's clinical definition of stroke. Data were collected on baseline characteristics, the degree of neurological impairment at admission (measured using the National Institutes of Health Stroke Scale), imaging and electrocardiogram (ECG) findings, and post-stroke complications. The modified Rankin scale (mRS) was used to assess stroke outcomes. Kaplan-Meier analysis was used to describe survival, and the Cox proportional hazards model was used to examine predictors of mortality.

Results

A total of 135 patients were enrolled, with a mean age of 64.5 years. Hypertension was observed in 76%, and 20% were on regular anti-hypertensive medications. The overall 30-day mortality rate was 37%. Comparing patients with hemorrhagic and ischemic stroke, 25% had died by day 5 [25th percentile survival time (in days): 5 (95% CI: 2-14)] versus day 23 [25th percentile survival time (in days): 23 (95% CI: 11-30) (log-rank p < 0.001)], respectively. Aspiration pneumonia was the most common medical complication, occurring in 41.3% of patients. ECG abnormalities were observed in 54.6 and 46.9% of patients with hemorrhagic and ischemic stroke, respectively. The most common patterns were as follows: ST changes 29.6 vs. 30.9%, T-wave inversion 34.1 vs. 38.3%, and U-waves 18.2 vs. 1.2% in hemorrhagic and ischemic stroke, respectively. Independent predictors for case mortality were as follows: mRS score at presentation (4-5) [aHR 5.50 (95% CI: 2.02-15.04)], aspiration pneumonia [aHR 3.69 (95% CI: 1.71-13.69)], ECG abnormalities [aHR 2.28 (95% CI: 1.86-5.86)], and baseline stroke severity [aHR 1.09 (95% CI: 1.02-1.17)].

Conclusion

Stroke is associated with a high 30-day mortality rate in Northwestern Tanzania. Concerted efforts are warranted in managing patients with stroke, with particular attention to individuals with severe strokes, ECG abnormalities, and swallowing difficulties to reduce early morbidity and mortality.

Ischemic Stroke at a Tertiary Academic Hospital in Tanzania: A Prospective Cohort Study With a Focus on Presumed Large Vessel Occlusion

Background

Large vessel ischemic strokes account for more than one-third of all strokes associated with substantial morbidity and mortality without early intervention. The incidence of large vessel occlusion (LVO) is not known in sub-Saharan Africa (SSA). Definitive vessel imaging is not routinely available in resource-limited settings.

Aims

We aimed to investigate the burden and outcomes of presumed LVO among patients with ischemic stroke admitted to a large tertiary academic hospital in Tanzania.

Methods

This cohort study recruited all consenting first-ever ischemic stroke participants admitted at a tertiary hospital in Tanzania. Demographic data were recorded, and participants were followed up to 1 year using the modified Rankin Scale (mRS). A diagnosis of presumed LVO was made by a diagnostic neuroradiologist and interventional neurologist based on contiguous ischemic changes in a pattern consistent with proximal LVO on a non-contrast computed tomography head. We examined factors associated with presumed LVO using logistic regression analysis. Inter-observer Kappa was calculated.

Results

We enrolled 158 first-ever ischemic strokes over 8 months with a mean age of 59.7 years. Presumed LVO accounted for 39.2% [95% confidence interval (CI) 31.6–47.3%] and an overall meantime from the onset of stroke symptoms to hospital arrival was 1.74 days. Participants with presumed LVO were more likely to involve the middle cerebral artery (MCA) territory (70.9%), p < 0.0001. Independent factors on multivariate analysis associated with presumed LVO were hypertension [adjusted odds ratio (aOR) 5.74 (95% CI: 1.74–18.9)] and increased waist-hip ratio [aOR 7.20 (95% CI: 1.83–28.2)]. One-year mortality in presumed LVO was 80% when compared with 73.1% in participants without presumed LVO. The Cohen's Kappa inter-observer reliability between the diagnostic neuroradiologist and interventional neurologist was 0.847.

Conclusion

There is a high burden of presumed LVO associated with high rates of 1-year morbidity and mortality at a tertiary academic hospital in Tanzania. Efforts are needed to confirm these findings with definitive vessel imaging, promoting cost-effective preventive strategies to reduce the burden of non-communicable diseases (NCDs), and a call for adopting endovascular therapies to reduce morbidity and mortality.

Tenecteplase in Ischemic Stroke: Challenge and Opportunity

PURPOSE OF REVIEW

Intravenous thrombolysis is the first-line therapy for ischemic stroke, and alteplase has been used as an intravenous thrombolysis drug for over 20 years. However, considering its low rate of recanalization and risk of intracerebral hemorrhage, alteplase may not be the optimal thrombolytic drug of choice for ischemic stroke. Tenecteplase (TNK) is a genetically engineered, mutant, tissue plasminogen activator that is a potential substitute to alteplase in ischemic stroke. The pharmacokinetic advantages of TNK include greater fibrin selectivity than alteplase and prolonged half-life time. In this review, we have summarized the clinical trials of TNK in ischemic stroke.

RECENT FINDINGS

Clinical trials showed a higher recanalization rate of TNK over alteplase without increasing the rate of intracerebral hemorrhage. However, not all clinical trials showed superiority of TNK over alteplase in functional outcomes and early neurological improvement. TNK was superior to alteplase in terms of recanalization in patients who fulfilled the imaging mismatch criteria and in those planning to undergo mechanical thrombectomy.

SUMMARY

TNK has the potential to substitute alteplase for ischemic stroke therapy. Future TNK clinical trials that target functional outcomes are warranted.

Controversies in Imaging of Patients with Acute Ischemic Stroke: AJR Expert Panel Narrative Review

The development of reperfusion therapies has profoundly impacted stroke care, initially with the advent of IV thrombolytic (IVT) treatment and, more recently, with the development and refinement of endovascular treatment (EVT). Progress in neuroimaging has supported the paradigm shift of stroke care, and advanced neuroimaging now has a fundamental role in triaging patients for both IVT and EVT. As the standard of care for acute ischemic stroke (AIS) evolves, controversies remain in certain clinical scenarios. This article explores the use of multimodality imaging for treatment selection of AIS in the context of recent guidelines, highlighting controversial topics and providing guidance for clinical practice. Results of major randomized trials supporting EVT are reviewed. Advantages and disadvantages of CT, CTA, MRI, and MRA in stroke diagnosis are summarized, with attention to level 1 evidence supporting the role of vascular imaging and perfusion imaging. Patient selection is compared between approaches based on time thresholds and physiologic approaches based on infarct core measurement using imaging. Moreover, various imaging approaches to core measurement are described. As ongoing studies push treatment boundaries, advanced imaging is expected to help identify a widening range of patients who may benefit from therapy.

Endovascular reperfusion outcomes in patients with a stroke and low ASPECTS is highly dependent on baseline infarct volumes

BACKGROUND

Patients with large vessel occlusion stroke (LVOS) and a low Alberta Stroke Program Early CT Score (ASPECTS) are often not offered endovascular therapy (ET) as they are thought to have a poor prognosis.

OBJECTIVE

To compare the outcomes of patients with low and high ASPECTS undergoing ET based on baseline infarct volumes.

METHODS

Review of a prospectively collected endovascular database at a tertiary care center between September 2010 and March 2020. All patients with anterior circulation LVOS and interpretable baseline CT perfusion (CTP) were included. Subjects were divided into groups with low ASPECTS (0-5) and high ASPECTS (6-10) and subsequently into limited and large CTP-core volumes (cerebral blood flow 30% >70 cc). The primary outcome measure was the difference in rates of 90-day good outcome as defined by a modified Rankin Scale (mRS) score of 0 to 2 across groups.

RESULTS

1248 patients fit the inclusion criteria. 125 patients had low ASPECTS, of whom 16 (12.8%) had a large core (LC), whereas 1123 patients presented with high ASPECTS, including 29 (2.6%) patients with a LC. In the category with a low ASPECTS, there was a trend towards lower rates of functional independence (90-day modified Rankin Scale (mRS) score 0-2) in the LC group (18.8% vs 38.9%, p=0.12), which became significant after adjusting for potential confounders in multivariable analysis (aOR=0.12, 95% CI 0.016 to 0.912, p=0.04). Likewise, LC was associated with significantly lower rates of functional independence (31% vs 51.9%, p=0.03; aOR=0.293, 95% CI 0.095 to 0.909, p=0.04) among patients with high ASPECTS.

CONCLUSIONS

Outcomes may vary significantly in the same ASPECTS category depending on infarct volume. Patients with ASPECTS ≤5 but baseline infarct volumes ≤70 cc may achieve independence in nearly 40% of the cases and thus should not be excluded from treatment.

Impact of recanalisation by mechanical thrombectomy in mild acute ischemic stroke with large anterior vessel occlusion

BACKGROUND

The net clinical benefit of mechanical thrombectomy (MT) in patients presenting acute anterior circulation ischemic stroke with large-vessel occlusion (AIS-LVO) and mild neurological deficit is uncertain.

AIMS

To investigate efficacy and safety of MT in patients with acute AIS-LVO and mild neurological deficit by evaluating i) the influence of recanalisation on three-month outcome and ii) mortality, symptomatic intracerebral hemorrhage (sICH) and procedural complications.

METHODS

We included consecutive patients with acute AIS-LVO and National Institute of Stroke Scale (NIHSS) score<8, treated by MT at Lille University Hospital. Recanalisation was graded according to modified thrombolysis in cerebral infarction (mTICI) score, mTICI 2b/2c/3 being considered successful. We recorded procedural complications and classified intra-cerebral hemorrhages (ICH) and sICH according with European Cooperative Acute Stroke Study (ECASS) and ECASS2 criteria. Three-month outcome was evaluated by modified Rankin scale (mRS). Excellent and favourable outcomes were respectively defined as mRS 0-1 and 0-2 (or similar to pre-stroke).

RESULTS

We included 95 patients. At three months, 56 patients (59. 0%) achieved an excellent outcome and 69 (72, 6%) a favourable outcome, both being more frequent in patients with successful recanalisation than in patients without (excellent outcome 71, 1% versus 10, 5%, P<0.001 and favourable outcome 82.9% versus 31.6%, P<0.001). The difference remained unchanged after adjustment for age and pre-MT infarct volume. Similar results were observed in patients with pre-MT NIHSS ≤5. Death occurred in five patients (5.3%), procedural complications in 12 (12.6%), any ICH in 38 (40.0%), including 3 (3.2%) sICH.

CONCLUSIONS

Achieving successful recanalisation appears beneficial and safe in acute AIS-LVO patients with NIHSS<8 before MT.

Revealing the Penumbra through Imaging Elemental Markers of Cellular Metabolism in an Ischemic Stroke Model

Stroke exacts a heavy financial and economic burden, is a leading cause of death, and is the leading cause of long-term disability in those who survive. The penumbra surrounds the ischemic core of the stroke lesion and is composed of cells that are stressed and vulnerable to death, which is due to an altered metabolic, oxidative, and ionic environment within the penumbra. Without therapeutic intervention, many cells within the penumbra will die and become part of the growing infarct, however, there is hope that appropriate therapies may allow potential recovery of cells within this tissue region, or at least slow the rate of cell death, therefore, slowing the spread of the ischemic infarct and minimizing the extent of tissue damage. As such, preserving the penumbra to promote functional brain recovery is a central goal in stroke research. While identification of the ischemic infarct, and the infarct/penumbra boundary is relatively trivial using classical histology and microscopy techniques, accurately assessing the penetration of the penumbra zone into undamaged brain tissue, and evaluating the magnitude of chemical alterations in the penumbra, has long been a major challenge to the stroke research field. In this study, we have used synchrotron-based X-ray fluorescence imaging to visualize the elemental changes in undamaged, penumbra, and infarct brain tissue, following ischemic stroke. We have employed a Gaussian mixture model to cluster tissue areas based on their elemental characteristics. The method separates the core of the infarct from healthy tissue, and also demarcates discrete regions encircling the infarct. These regions of interest can be combined with elemental and metabolic data, as well as with conventional histology. The cell populations defined by clustering provide a reproducible means of visualizing the size and extent of the penumbra at the level of the single cell and provide a critically needed tool to track changes in elemental status and penumbra size.

The Accuracy of Serum Matrix Metalloproteinase-9 for Predicting Hemorrhagic Transformation After Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

Hemorrhagic transformation is a serious complication of acute ischemic stroke, which may cause detrimental outcomes and the delayed use of anticoagulation therapy. Early predicting and identifying the patients at high risk of hemorrhagic transformation before clinical deterioration occurrence become a research priority.

OBJECTIVE

To study the value of plasma matrix metalloproteinase-9 predicting hemorrhagic transformation after ischemic stroke.

METHODS

We searched PubMed, Ovid, Cochrane Library, and other 2 Chinese databases to identify literatures published up to September 2017 and performed meta-analysis by STATA (version 12.0, StataCorp LP, College Station, TX).

RESULTS

Twelve studies incorporating 1492 participants were included and 7 studies were included in the quantitative statistical analysis. The pooled sensitivity was 85% (95% confidence interval [CI]: 75%, 91%) and the pooled specificity was 79% (95% CI: 67%, 87%). The area under the receiver operating characteristic curve was .89 (95% CI .86, .91). Significant heterogeneity for all estimates value existed (all the P value < .05 and I² > 50%). There is no threshold effect with P value greater than .05 of the correlation coefficient. Meta-regression and subgroup analysis showed cut-off value and hemorrhagic subtype contributed to heterogeneity. Deeks' funnel plot indicated no significant publication bias for 7 quantitative analysis studies.

CONCLUSIONS

Matrix metalloproteinase-9 has high predictive value for hemorrhagic transformation after acute ischemic stroke. It may be useful to test matrix metalloproteinase-9 to exclude patients at low risk of hemorrhage for precise treatment in the future clinical work.

Therapeutic Fibrinolysis: How Efficacy and Safety Can Be Improved

Therapeutic fibrinolysis has been dominated by the experience with tissue-type plasminogen activator (t-PA), which proved little better than streptokinase in acute myocardial infarction. In contrast, endogenous fibrinolysis, using one-thousandth of the t-PA concentration, is regularly lysing fibrin and induced Thrombolysis In Myocardial Infarction flow grade 3 patency in 15% of patients with acute myocardial infarction. This efficacy is due to the effects of t-PA and urokinase plasminogen activator (uPA). They are complementary in fibrinolysis so that in combination, their effect is synergistic. Lysis of intact fibrin is initiated by t-PA, and uPA activates the remaining plasminogens. Knockout of the uPA gene, but not the t-PA gene, inhibited fibrinolysis. In the clinic, a minibolus of t-PA followed by an infusion of uPA was administered to 101 patients with acute myocardial infarction; superior infarct artery patency, no reocclusions, and 1% mortality resulted. Endogenous fibrinolysis may provide a paradigm that is relevant for therapeutic fibrinolysis.

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.

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.

Long-Term Outcome as Function of Blood Pressure in Acute Ischemic Stroke and Effects of Thrombolysis

BACKGROUND

While baseline blood pressure (BP) is a known predictor of 90-day residual deficit after acute ischemic stroke, the effect of thrombolysis on this relationship has not been described. To study the interaction and to find intervals of prognostic significance, the functional forms of this predictive relationship should be found and compared for recombinant tissue plasminogen activator (rt-PA)- and placebo-treated patients of the first European Cooperative Acute Stroke Study.

METHODS

We studied the 615 patients with acute ischemic hemispheric stroke randomized and treated in the first European Cooperative Acute Stroke Study. Endpoints were fatal outcome within and favorable outcome (no or negligible long-term handicap on the modified Rankin Scale scores 0 or 1) after 90 +/- 14 days. Functional relationships with baseline BP were estimated fully nonparametrically as moving averages of occurrences of either outcome among placebo- and rt-PA-treated patients, separately. Visual findings were corroborated by conventionally stratified logistic regression.

RESULTS

For favorable outcome, an S-shaped functional relationship with baseline systolic BP (SBP) was found with an averaged incremental rate around 10% per 1 mm Hg increase in baseline SBP between 140 and 160 mm Hg, among rt-PA and placebo patients. Similar results were obtained for diastolic BP (DBP) between 80 and 90 mm Hg. Odds ratios in favor of rt-PA were 1.96 (95% CI: 1.02-3.78) and 2.87 (95% CI: 1.36-6.04) for SBP and DBP in these intervals, respectively. For mortality, visible markedly lower risks in the placebo group between 120 and 140 and between 160 and 180 mm Hg SBP were confirmed with adjusted OR of 2.47 (95% CI: 1.09-5.64) and 9.73 (95% CI: 2.02-46.82), respectively.

CONCLUSIONS

Patients benefited from rt-PA in terms of no or negligible handicap after 90 days, without excess risk of death, with baseline SBP between 140 and 160 mm Hg or baseline DBP between 80 and 90 mm Hg.

Characteristics of Blood Pressure Profiles as Predictors of Long-Term Outcome After Acute Ischemic Stroke

Background and Purpose— Most patients have elevated blood pressure (BP) in the early phase after an acute ischemic stroke. Mechanism and effects of this BP elevation are not well understood. The benefits of intervention by lowering the initial BP or waiting for spontaneous return to normal values remain debated. We studied the hypothesis that increased BP level and profile variability will adversely affect long-term outcome after stroke with and without thrombolytic treatment.

Methods— We studied the 615 patients with acute ischemic hemispheric stroke in the first European Cooperative Acute Stroke Study (ECASS). BP was measured at 2-hour intervals during the first 20 hours after randomization, and then every 4 hours, up to 72 hours after admission. Studied features of individual 0- to 72-hour BP profiles were: baseline BP, maximum and minimum BP, mean level, and successive variation in the BP profile. The end point was good functional recovery (modified Rankin Scale [mRS] score of 0 to 1) at 90 days. Logistic regression was used to adjust for known prognostic factors, demographic, initial stroke severity, disease and medication histories, and computed tomography signs.

Results— Higher systolic BP or diastolic BP at baseline were associated with favorable outcome assessed on modified mRS at 90 days (adjusted odds ratio [OR], 1.22; 95% CI, 1.01 to 1.49; and OR, 1.22; 95% CI, 1.01 to 1.49 per 10 mm Hg), lower within-patient 0- to 72-hour average systolic BP (SBP), or DBP implied favorable outcome (OR, 0.74; 95% CI, 0.61 to 0.90; and OR, 0.61; 95% CI, 0.41 to 0.90 per 10 mm Hg). Reduced variability of 0- to 72-hour DBP profile was an independent predictor of favorable outcome (OR, 0.58; 95% CI, 0.39 to 0.85 per 5 mm Hg).

Conclusions— Higher baseline SBP or DBP was associated with favorable outcome after stroke. Other characteristics of first 72-hour BP profiles: lower mean level of SBP or DBP and reduced successive variability of DBP profile were independent predictors of favorable outcome at 90 days.

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).

Neurological deterioration in acute ischemic stroke: potential predictors and associated factors in the European cooperative acute stroke study (ECASS) I

BACKGROUND AND PURPOSE

The present study was undertaken to identify potential predictors of and factors associated with early and late progression in acute stroke. We performed secondary analysis of the clinical, biochemical, and radiological data recorded in the acute phase of stroke patients enrolled in the European Cooperative Acute Stroke Study (ECASS) I.

METHODS

Early progressing stroke (EPS) was diagnosed when there was a decrease of > or = 2 points in consciousness or motor power or a decrease of > or = 3 points in speech scores in the Scandinavian Neurological Stroke Scale from baseline to the 24-hour evaluation, and late progressing stroke (LPS) was diagnosed when 1 of these decreases occurred between the 24-hour evaluation and the evaluation at day 7. Using logistic regression analyses, we looked for baseline variables that predicted EPS and LPS and for factors measured after the early or late acute phase and associated with the 2 clinical courses.

RESULTS

Of the 615 patients studied, 231 (37.5%) worsened during the first 24 hours after inclusion. The overall incidence of EPS was 37% in the placebo group and 38% in the recombinant tissue plasminogen activator group (P=0.68, Fisher's Exact Test). Focal hypodensity (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.3 to 2.9) and hyperdensity of the middle cerebral artery sign (OR, 1.8; 95% CI, 1.1 to 3.1) on baseline computed tomography, longer delay until treatment (OR, 1.2; 95% CI, 1.1 to 1. 4) and history of coronary heart disease (OR, 1.7; 95% CI, 1.1 to 2. 8) and diabetes (OR, 1.8; 95% CI, 1.0 to 3.1) were independent prognostic factors for EPS. Extent of hypodensity >33% in the middle cerebral artery territory (OR, 2.5; 95% CI, 1.6 to 4.0) and brain swelling (OR, 1.8; 95% CI, 1.1 to 3.2) on CT at 24 hours but not hemorrhagic transformation of cerebral infarct nor decrease in systolic blood pressure within the first 24 hours after treatment were associated with EPS in multivariate analyses. LPS was observed in 20.3% of patients. Older age, a low neurological score, and brain swelling at admission independently predicted late worsening.

CONCLUSION

In the setting of a multicenter trial, EPS and LPS are mainly related to computed tomographic signs of cerebral edema. Treatment with recombinant tissue plasminogen activator, hemorrhagic transformation, and moderate changes in systolic blood pressure did not influence the early clinical course.

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

BACKGROUND AND PURPOSE

It is not yet known which end points are the most suitable for evaluation of the effects of acute stroke intervention. The European Cooperative Acute Stroke Study (ECASS) I study used 2 primary end points. The study was powered to detect a 15% improvement of the median of each primary end point. The study failed to show this effect and was negative in the intention-to-treat analysis. The National Institute of Neurological Disorders and Stroke (NINDS) study used 4 dichotomized end points and applied a global end-point analysis. This study was positive and led to FDA approval of thrombolytic therapy for acute ischemic stroke. This study was undertaken to answer the question of whether a different statistical design may have shown a positive results of the ECASS I trial.

METHODS

We performed a retrospective analysis of the ECASS I intention-to-treat data set (615 randomized and treated patients, rtPA treatment versus placebo) and post hoc application of the NINDS trial statistical methodology (global end-point analysis). The scores of the modified Rankin Scale (mRS), Barthel Index (BI), and the National Institutes of Health Stroke Scale (NIHSS) were dichotomized according to the criteria used in the NINDS trial. Favorable outcome was defined as a score of 0 or 1 on mRS, a score of 95 or 100 on BI, and a score of 0 or 1 on NIHSS.

RESULTS

The number of patients reaching favorable outcome were higher in all 3 end points in the rtPA-treated group. The effect sizes were 8% for mRS, 6% for BI, and 14% for NIHSS, respectively. The differences are statistically significant for the mRS (P=0.044; odds ratio [OR], 1. 4; 95% confidence interval [CI], 1.0 to 2.0) and the NIHSS (P=0.001; OR, 1.9; 95% CI, 1.4 to 2.8), while for the BI significance was missed (P=0.102; OR, 1.3; 95% CI, 0.9 to 1.8). The global end-point statistics, however, shows a significant increase (P=0.008; OR, 1.5; 95% CI, 1.1 to 2.0) of favorable outcome in the rtPA-treated patient group.

CONCLUSIONS

Using the global end-point analysis, ECASS is positive in the intention-to-treat analysis. This may indicate that the time window for thrombolysis may be as long as 6 hours. Looking at the 3 dichotomized end points, the effect sizes for 2 end points, mRS and BI, are smaller in the ECASS 6-hour intention-to-treat population compared with the NINDS trial, whereas the effect size for the NIHSS is larger. While in the NINDS trial all 3 end points reveal statistically significant results, in ECASS only 2 of the 3 corresponding end points, mRS and NIHSS, were statistically significant. This finding underlines an important difference of a global end-point approach: it may show a positive overall result although one of the end points is not positive.

Hemorrhagic transformation in acute ischemic stroke. Potential contributing factors in the European Cooperative Acute Stroke Study

BACKGROUND AND PURPOSE

Recent studies suggest that thrombolytic therapy may be of benefit to patients with acute ischemic stroke. However, the treatment also carries a significant risk of hemorrhagic transformation (HT). The purpose of this study was to select potential contributors to HT.

METHODS

We provide an explanatory analysis of the European Cooperative Acute Stroke Study (ECASS) data. ECASS was a multicenter, placebo-controlled, randomized trial of recombinant tissue plasminogen activator in ischemic stroke, within 6 hours of symptom onset, which enrolled 620 patients. HTs were classified into either hemorrhagic infarction or parenchymal hemorrhage according to their CT scan appearance. We used logistic regression analysis to select potential contributing factors to each type of HT.

RESULTS

The severity of initial clinical deficit (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.6 to 4.0) and the presence of early ischemic changes on CT scan (OR, 3.5; 95% CI, 2.3 to 5.3) were associated with increased risk of hemorrhagic infarction. Increasing age (in decades; OR, 1.3; 95% CI, 1.0 to 1.7) and treatment with recombinant tissue plasminogen activator (OR, 3.6; 95% CI, 2.1 to 6.1) were related to the risk of parenchymal hemorrhage.

CONCLUSIONS

Since all potential contributing factors are readily discernible upon hospital admission, they should be used to improve selection of patients into future studies.