A multicentre, double-blind, randomized study to compare the safety and efficacy of once-daily ORG 10172 and twice-daily low-dose heparin in preventing deep-vein thrombosis in patients with acute ischaemic stroke

Anticoagulants for thrombosis prophylaxis in acutely ill patients admitted to hospital: systematic review and network meta-analysis

OBJECTIVE

To assess the benefits and harms of different types and doses of anticoagulant drugs for the prevention of venous thromboembolism in patients who are acutely ill and admitted to hospital.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

Cochrane CENTRAL, PubMed/Medline, Embase, Web of Science, clinical trial registries, and national health authority databases. The search was last updated on 16 November 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Published and unpublished randomised controlled trials that evaluated low or intermediate dose low-molecular-weight heparin, low or intermediate dose unfractionated heparin, direct oral anticoagulants, pentasaccharides, placebo, or no intervention for the prevention of venous thromboembolism in acutely ill adult patients in hospital.

MAIN OUTCOME MEASURES

Random effects, bayesian network meta-analyses used four co-primary outcomes: all cause mortality, symptomatic venous thromboembolism, major bleeding, and serious adverse events at or closest timing to 90 days. Risk of bias was also assessed using the Cochrane risk-of-bias 2.0 tool. The quality of evidence was graded using the Confidence in Network Meta-Analysis framework.

RESULTS

44 randomised controlled trials that randomly assigned 90 095 participants were included in the main analysis. Evidence of low to moderate quality suggested none of the interventions reduced all cause mortality compared with placebo. Pentasaccharides (odds ratio 0.32, 95% credible interval 0.08 to 1.07), intermediate dose low-molecular-weight heparin (0.66, 0.46 to 0.93), direct oral anticoagulants (0.68, 0.33 to 1.34), and intermediate dose unfractionated heparin (0.71, 0.43 to 1.19) were most likely to reduce symptomatic venous thromboembolism (very low to low quality evidence). Intermediate dose unfractionated heparin (2.63, 1.00 to 6.21) and direct oral anticoagulants (2.31, 0.82 to 6.47) were most likely to increase major bleeding (low to moderate quality evidence). No conclusive differences were noted between interventions regarding serious adverse events (very low to low quality evidence). When compared with no intervention instead of placebo, all active interventions did more favourably with regard to risk of venous thromboembolism and mortality, and less favourably with regard to risk of major bleeding. The results were robust in prespecified sensitivity and subgroup analyses.

CONCLUSIONS

Low-molecular-weight heparin in an intermediate dose appears to confer the best balance of benefits and harms for prevention of venous thromboembolism. Unfractionated heparin, in particular the intermediate dose, and direct oral anticoagulants had the least favourable profile. A systematic discrepancy was noted in intervention effects that depended on whether placebo or no intervention was the reference treatment. Main limitations of this study include the quality of the evidence, which was generally low to moderate due to imprecision and within-study bias, and statistical inconsistency, which was addressed post hoc.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020173088.

Anticoagulants for acute ischaemic stroke

BACKGROUND

Stroke is the third leading cause of early death worldwide. Most ischaemic strokes are caused by a blood clot blocking an artery in the brain. Patient outcomes might be improved if they are offered anticoagulants that reduce their risk of developing new blood clots and do not increase the risk of bleeding. This is an update of a Cochrane Review first published in 1995, with updates in 2004, 2008, and 2015.

OBJECTIVES

To assess the effectiveness and safety of early anticoagulation (within the first 14 days of onset) for people with acute presumed or confirmed ischaemic stroke. Our hypotheses were that, compared with a policy of avoiding their use, early anticoagulation would be associated with: • reduced risk of death or dependence in activities of daily living a few months after stroke onset; • reduced risk of early recurrent ischaemic stroke; • increased risk of symptomatic intracranial and extracranial haemorrhage; and • reduced risk of deep vein thrombosis and pulmonary embolism.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (August 2021); the Cochrane Database of Systematic Reviews (CDSR); the Cochrane Central Register of Controlled Trials (CENTRAL; 2021, Issue 7), in the Cochrane Library (searched 5 August 2021); MEDLINE (2014 to 5 August 2021); and Embase (2014 to 5 August 2021). In addition, we searched ongoing trials registries and reference lists of relevant papers. For previous versions of this review, we searched the register of the Antithrombotic Trialists' (ATT) Collaboration, consulted MedStrategy (1995), and contacted relevant drug companies.

SELECTION CRITERIA

Randomised trials comparing early anticoagulant therapy (started within two weeks of stroke onset) with control in people with acute presumed or confirmed ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data. We assessed the overall certainty of the evidence for each outcome using RoB1 and GRADE methods.

MAIN RESULTS

We included 28 trials involving 24,025 participants. Quality of the trials varied considerably. We considered some studies to be at unclear or high risk of selection, performance, detection, attrition, or reporting bias. Anticoagulants tested were standard unfractionated heparin, low-molecular-weight heparins, heparinoids, oral anticoagulants, and thrombin inhibitors. Over 90% of the evidence is related to effects of anticoagulant therapy initiated within the first 48 hours of onset. No evidence suggests that early anticoagulation reduced the odds of death or dependence at the end of follow-up (odds ratio (OR) 0.98, 95% confidence interval (CI) 0.92 to 1.03; 12 RCTs, 22,428 participants; high-certainty evidence). Similarly, we found no evidence suggesting that anticoagulant therapy started within the first 14 days of stroke onset reduced the odds of death from all causes (OR 0.99, 95% CI 0.90 to 1.09; 22 RCTs, 22,602 participants; low-certainty evidence) during the treatment period. Although early anticoagulant therapy was associated with fewer recurrent ischaemic strokes (OR 0.75, 95% CI 0.65 to 0.88; 12 RCTs, 21,665 participants; moderate-certainty evidence), it was also associated with an increase in symptomatic intracranial haemorrhage (OR 2.47; 95% CI 1.90 to 3.21; 20 RCTs, 23,221 participants; moderate-certainty evidence). Similarly, early anticoagulation reduced the frequency of symptomatic pulmonary emboli (OR 0.60, 95% CI 0.44 to 0.81; 14 RCTs, 22,544 participants; high-certainty evidence), but this benefit was offset by an increase in extracranial haemorrhage (OR 2.99, 95% CI 2.24 to 3.99; 18 RCTs, 22,255 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Since the last version of this review, four new relevant studies have been published, and conclusions remain consistent. People who have early anticoagulant therapy after acute ischaemic stroke do not demonstrate any net short- or long-term benefit. Treatment with anticoagulants reduced recurrent stroke, deep vein thrombosis, and pulmonary embolism but increased bleeding risk. Data do not support the routine use of any of the currently available anticoagulants for acute ischaemic stroke.

Short-Term and Long-Term Safety and Efficacy of Treatment of Acute Ischemic Stroke with Low-Molecular-Weight Heparin: Meta-Analysis of 19 Randomized Controlled Trials

OBJECTIVE

Currently, it remains controversial about guidelines for the application of low-molecular-weight heparin (LMWH) in patients with acute ischemic stroke (AIS). Therefore this meta-analysis was carried out, aiming to systematically investigate the short-term and long-term safety and efficacy of LMWH in AIS patients.

METHODS

Three electronic databases-PubMed, Embase database, and Cochrane library-were comprehensively retrieved by 2 investigators independently. Finally, a total of 19 randomized controlled trials were enrolled for analysis. The safety endpoints in this study included all-cause mortality and the risk of bleeding (major, minor, or cerebral hemorrhage). The efficacy endpoints were the prevention of deep vein thrombosis (DVT) and recurrent stroke.

RESULTS

The application of LMWH led to a decreased risk of DVT, and there was no significant association in all-cause mortality or recurrent stroke. According to age-stratified analyses, the risk of all-cause mortality increased by 39% (risk ratio 1.39, 1.03-1.88; I² 0%) in AIS patients aged older than 70 years who used LMWH for 14 days, and there was no significant effect on preventing DVT (risk ratio 0.69, 0.14-3.52; I² 26.4%) in patients aged younger than 70 years old within 3 months. Moreover, enoxaparin and danaparoid were more effective at preventing DVT, regardless of age.

CONCLUSIONS

To sum up, on the basis of limited studies available currently, the early use of LMWH in AIS patients aged older than 70 years should be cautious because it may increase the risk of all-cause mortality. For patients younger than 70 years old, the early use of LMWH significantly reduces the short-term risk of DVT, but there is no significant relationship in the long term. In terms of DVT prevention, enoxaparin and danaparoid are probably more effective. Nonetheless, more future randomized controlled trials are warranted to verify and support this conclusion.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: prophylaxis for hospitalized and nonhospitalized medical patients

BACKGROUND

Venous thromboembolism (VTE) is the third most common vascular disease. Medical inpatients, long-term care residents, persons with minor injuries, and long-distance travelers are at increased risk.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support patients, clinicians, and others in decisions about preventing VTE in these groups.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and adult patients. The Grading of Recommendations Assessment, Development and Evaluation approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 19 recommendations for acutely ill and critically ill medical inpatients, people in long-term care facilities, outpatients with minor injuries, and long-distance travelers.

CONCLUSIONS

Strong recommendations included provision of pharmacological VTE prophylaxis in acutely or critically ill inpatients at acceptable bleeding risk, use of mechanical prophylaxis when bleeding risk is unacceptable, against the use of direct oral anticoagulants during hospitalization, and against extending pharmacological prophylaxis after hospital discharge. Conditional recommendations included not to use VTE prophylaxis routinely in long-term care patients or outpatients with minor VTE risk factors. The panel conditionally recommended use of graduated compression stockings or low-molecular-weight heparin in long-distance travelers only if they are at high risk for VTE.

Deep Vein Thrombosis in Acute Stroke - A Systemic Review of the Literature

We present a systemic review of available literature on the complications of deep venous thrombosis that develops in patients presenting with acute stroke. There are several pharmacological and physical treatment options available and used. We aim to summarize the management plans currently used at different centers. In conclusion, low-dose anticoagulant therapy for ischemic stroke is recommended. In the case of intracerebral hemorrhage, pneumatic sequential compression devices should be placed initially, followed by the administration of ultra-fractioned heparin on the next day, and then oral anticoagulant therapy to replace the heparin after a week in high-risk patients. Similar prophylactic treatment recommendations are used for subarachnoid hemorrhage.

Low-molecular-weight heparins or heparinoids versus standard unfractionated heparin for acute ischaemic stroke

BACKGROUND

Low-molecular-weight heparins (LMWHs) and heparinoids are anticoagulants that may have more powerful antithrombotic effects than standard unfractionated heparin (UFH) but a lower risk of bleeding complications. This is an update of the original Cochrane Review of these agents, first published in 2001 and last updated in 2008.

OBJECTIVES

To determine whether antithrombotic therapy with LMWHs or heparinoids is associated with a reduction in the proportion of people who are dead or dependent for activities in daily living compared with UFH.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched February 2017), the Cochrane Central Register of Controlled Trials (CENTRAL: the Cochrane Library Issue 1, 2017), MEDLINE (1966 to February 2017), and Embase (1980 to February 2017). We also searched trials registers to February 2017: ClinicalTrials.gov, EU Clinical Trials Register, Stroke Trials Registry, ISRCTN Registry and the World Health Organization (WHO) International Clinical Trials Registry Platform.

SELECTION CRITERIA

Unconfounded randomised trials comparing LMWH or heparinoids with standard UFH in people with acute ischaemic stroke, in which participants were recruited within 14 days of stroke onset.

DATA COLLECTION AND ANALYSIS

Two review authors independently chose studies for inclusion, assessed risk of bias and trial quality, extracted and analysed the data. Differences were resolved by discussion.

MAIN RESULTS

We included nine trials involving 3137 participants. We did not identify any new trials for inclusion in this updated review. None of the studies reported data on the primary outcome in sufficient detail to enable analysis for the review. Overall, there was a moderate risk of bias in the included studies. Compared with UFH, there was no evidence of an effect of LMWH or heparinoids on death from all causes during the treatment period (96/1616 allocated LMWH/heparinoid versus 78/1486 allocated UFH; odds ratio (OR) 1.06, 95% CI 0.78 to 1.47; 8 trials, 3102 participants, low quality evidence). LMWH or heparinoid were associated with a significant reduction in deep vein thrombosis (DVT) compared with UFH (OR 0.55, 95% CI 0.44 to 0.70, 7 trials, 2585 participants, low quality evidence). However, the number of the major clinical events such as pulmonary embolism (PE) and intracranial haemorrhage was too small to provide a reliable estimate of the effects.

AUTHORS' CONCLUSIONS

Treatment with a LMWH or heparinoid after acute ischaemic stroke appears to decrease the occurrence of DVT compared with standard UFH, but there are too few data to provide reliable information on their effects on other important outcomes, including functional outcome, death and intracranial haemorrhage.

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

Background

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

Methods

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

Results

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

Conclusions

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

Heparin and related drugs for venous thromboembolism prophylaxis: subcutaneous or intravenous continuous infusion?

In this article, the most evidenced approaches of unfractionated heparin administration for prevention of venous thromboembolism in medical and surgical hospitalized patients will be reviewed. Present data were collected by searching Scopus, PubMed, MEDLINE, Science direct, Clinical trials and Cochrane database systematic reviews. Subcutaneous low doses of unfractionated heparin (10000–15000 IU) in two or three divided doses per day are commonly administrated for venous thromboembolism prevention in different medical and surgical populations. In some populations such as obese surgical and critically ill patients, due to altered pharmacokinetics behavior of unfractionated heparin, continuous intravenous infusion of the low doses of unfractionated heparin has been proposed.

Prevention of Venous Thromboembolism After Stroke

Venous thromboembolism (VTE) is a common complication following acute ischemic and hemorrhagic stroke. Pulmonary embolism (PE), the most serious consequence of deep vein thrombosis (DVT), can result in significant morbidity and death. Patients with stroke are at particular risk because of limb paralysis, prolonged bed rest, and increased prothrombotic activity. Preventive measures should be taken at all levels of care and can include mechanical calf compression, antiplatelet agents, and the use of anticoagulants such as heparin and low molecular weight heparin. Prevention of VTE should be incorporated into all stroke care pathways.

Trends in Hospital Admission for Stroke in Calgary

Background:

Stroke incidence has fallen since 1950. Recent trends suggest that stroke incidence may be stabilizing or increasing. We investigated time trends in stroke occurrence and in-hospital morbidity and mortality in the Calgary Health Region.

Methods:

All patients admitted to hospitals in the Calgary Health Region between 1994 and 2002 with a primary discharge diagnosis code (ICD-9 or ICD-10) of stroke were included. In-hospital strokes were also included. Stroke type, date of admission, age, gender, discharge disposition (died, discharged) and in-hospital complications (pneumonia, pulmonary embolism, deep venous thrombosis) were recorded. Poisson and simple linear regression was used to model time trends of occurrence by stroke type and age-group and to extrapolate future time trends.

Results:

From 1994 to 2002, 11642 stroke events were observed. Of these, 9879 patients (84.8%) were discharged from hospital, 1763 (15.1%) died in hospital, and 591 (5.1%) developed in-hospital complications from pneumonia, pulmonary embolism or deep venous thrombosis. Both in-hospital mortality and complication rates were highest for hemorrhages. Over the period of study, the rate of stroke admission has remained stable. However, total numbers of stroke admission to hospital have faced a significant increase (p=0.012) due to the combination of increases in intracerebral hemorrhage (p=0.021) and ischemic stroke admissions (p=0.011). Sub-arachnoid hemorrhage rates have declined. In-hospital stroke mortality has experienced an overall decline due to a decrease in deaths from ischemic stroke, intracerebral hemorrhage and sub-arachnoid hemorrhage.

Conclusion:

Although age-adjusted stroke occurrence rates were stable from 1994 to 2002, this is associated with both a sharp increase in the absolute number of stroke admissions and decline in proportional in-hospital mortality. Further research is needed into changes in stroke severity over time to understand the causes of declining in-hospital stroke mortality rates.

Thrombo-prophylaxis in acutely ill medical and critically ill patients

Thrombo-prophylaxis has been shown to reduce the incidence of pulmonary embolism (PE) and mortality in surgical patients. The purpose of this review is to find out the evidence-based clinical practice criteria of deep vein thrombosis (DVT) prophylaxis in acutely ill medical and critically ill patients. English-language randomized controlled trials, systematic reviews, and meta-analysis were included if they provided clinical outcomes and evaluated therapy with low-dose heparin or related agents compared with placebo, no treatment, or other active prophylaxis in the critically ill and medically ill population. For the same, we searched MEDLINE, PUBMED, Cochrane Library, and Google Scholar. In acutely ill medical patients on the basis of meta-analysis by Lederle et al. (40 trials) and LIFENOX study, heparin prophylaxis had no significant effect on mortality. The prophylaxis may have reduced PE in acutely ill medical patients, but led to more bleeding events, thus resulting in no net benefit. In critically ill patients, results of meta-analysis by Alhazzani et al. and PROTECT Trial indicate that any heparin prophylaxis compared with placebo reduces the rate of DVT and PE, but not symptomatic DVT. Major bleeding risk and mortality rates were similar. On the basis of MAGELLAN trial and EINSTEIN program, rivaroxaban offers a single-drug approach to the short-term and continued treatment of venous thrombosis. Aspirin has been used as antiplatelet agent, but when the data from two trials the ASPIRE and WARFASA study were pooled, there was a 32% reduction in the rate of recurrence of venous thrombo-embolism and a 34% reduction in the rate of major vascular events.

Prevention of Deep Vein Thrombosis and Pulmonary Embolism in Patients With Stroke

Venous thromboembolism (VTE), encompassing deep venous thrombosis and pulmonary embolism, is a potentially fatal but preventable complication of stroke. Reported rates of VTE after stroke have decreased over the last four decades, possibly due to the implementation of stroke units, early mobilization and hydration, and increased early use of antiplatelets. Additional means of thromboprophylaxis in stroke include mechanical methods (ie, compression stockings) to prevent venous stasis and medical therapy including antiplatelets, heparins, and heparinoids. Risk of VTE must be balanced by potential risk of hemorrhagic complications from pharmacotherapy. Unfractionated heparin, low-molecular-weight heparin (LMWH), and danaparoid are acceptable options for chemoprophylaxis though none have shown superior efficacy for VTE prevention without an associated increase in major hemorrhage. The efficacy and timing of pharmacological thromboprophylaxis in hemorrhagic stroke are not well defined. Graduated compression stockings are associated with an increased rate of adverse events and are not recommended and intermittent pneumatic compression stockings require further investigation.

Low-molecular-weight heparins or heparinoids versus standard unfractionated heparin for acute ischaemic stroke

BACKGROUND

Low-molecular-weight heparins and heparinoids are anticoagulants that may be associated with lower risks of haemorrhage and more powerful antithrombotic effects than standard unfractionated heparin. This is an updated version of the original Cochrane review first published in Issue 1, 1995 and previously updated in Issue 2, 2005.

OBJECTIVES

To compare the effects of low-molecular-weight heparins or heparinoids with those of unfractionated heparin in people with acute, confirmed or presumed, ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched June 2007). In addition we searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2007), MEDLINE (1966 to June 2007) and EMBASE (1980 to June 2007). For previous versions of this review we searched MedStrategy (1995) and also contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing heparinoids or low-molecular-weight heparins with standard unfractionated heparin in people with acute ischaemic stroke. We only included trials where treatment was started within 14 days of stroke onset.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Nine trials involving 3137 people were included. Four trials compared a heparinoid (danaparoid), four trials compared low-molecular-weight heparin (enoxaparin or certoparin), and one trial compared an unspecified low-molecular-weight heparin with standard unfractionated heparin. Allocation to low-molecular-weight heparin or heparinoid was associated with a significant reduction in the odds of deep vein thrombosis compared with standard unfractionated heparin (odds ratio (OR) 0.55, 95% confidence interval (CI) 0.44 to 0.70). However, the number of more major events (pulmonary embolism, death, intracranial or extracranial haemorrhage) was too small to provide a reliable estimate of the benefits and risks of low-molecular-weight heparins or heparinoids compared with standard unfractionated heparin for these, arguably more important, outcomes. Insufficient information was available to assess effects on recurrent stroke or functional outcome.

AUTHORS' CONCLUSIONS

Since the last version of this review none of the three new relevant studies with 2397 participants have provided additional information to change the conclusions. Treatment with a low-molecular-weight heparin or heparinoid after acute ischaemic stroke appears to decrease the occurrence of deep vein thrombosis compared with standard unfractionated heparin, but there are too few data to provide reliable information on their effects on other important outcomes, including death and intracranial haemorrhage.

Prevention of deep venous thrombosis and pulmonary embolism following stroke: a systematic review of published articles

We performed a systematic review of the literature on venous thromboembolism (VTE) prophylaxis following cerebral infarct (CI) and haemorrhagic stroke. MEDLINE, Cochrane, LILACS and SciELO databases were scanned, and the Abstracts from Brazilian, American and European Neurology and Stroke Congresses were scrutinized for clinical trials. Moreover, the reference lists of articles and reviews were searched. A pooled analysis of two large studies with aspirin was made. Both unfractionated heparin and low molecular weight heparins/heparinoids (LMWH) are partially effective for VTE prophylaxis after CI, and should be routinely used in patients with motor deficit and reduced mobility and no contraindications. Reduction of deep venous thrombosis is better established than the effect over pulmonary embolism or mortality. Some evidence points to a greater efficacy of LMWH. The available evidence does not support the use of mechanical methods or dextran. Aspirin may have a mild protective effect. Low-dose Warfarin might be useful in the rehabilitation setting. Strict recommendations cannot be made in patients with haemorrhagic stroke but intermittent pneumatic compression merits further study. There are important limitations of current VTE preventive strategies following stroke. Additional studies on the combination of methods after CI and of low doses of anticoagulants following cerebral haemorrhage are urgently needed.

Efficacy and Safety of Anticoagulant Treatment in Acute Cardioembolic Stroke

Background and Purpose— The role of anticoagulant treatment for acute cardioembolic stroke is uncertain. We performed an updated meta-analysis of all randomized trials to obtain the best estimates of the efficacy and safety of anticoagulants for the initial treatment of acute cardioembolic stroke.

Methods— Using electronic and manual searches of the literature, we identified randomized trials comparing anticoagulants (unfractionated heparin or low-molecular-weight heparin or heparinoids), started within 48 hours, with other treatments (aspirin or placebo) in patients with acute ischemic cardioembolic stroke. Two reviewers independently selected studies and extracted data on study design, quality, and clinical outcomes, including death or disability, all strokes, recurrent ischemic stroke, and cerebral symptomatic bleeding. Odds ratios for individual outcomes were calculated for each trial and data from all the trials were pooled using the Mantel-Haenszel method.

Results— Seven trials, involving 4624 patients with acute cardioembolic stroke, met the criteria for inclusion. Compared with other treatments, anticoagulants were associated with a nonsignificant reduction in recurrent ischemic stroke within 7 to 14 days (3.0% versus 4.9%, odds ratio 0.68, 95% CI: 0.44 to 1.06, P =0.09, number needed to treat=53), a significant increase in symptomatic intracranial bleeding (2.5% versus 0.7%, odds ratio 2.89; 95% CI: 1.19 to 7.01, P =0.02, number needed to harm=55), and a similar rate of death or disability at final follow up (73.5% versus 73.8%, odds ratio 1.01; 95% CI: 0.82 to 1.24, P =0.9).

Conclusions— Our findings indicate that in patients with acute cardioembolic stroke, early anticoagulation is associated with a nonsignificant reduction in recurrence of ischemic stroke, no substantial reduction in death and disability, and an increased intracranial bleeding.

Established treatments for acute ischaemic stroke

This article reviews the recommended management of patients presenting to accident and emergency departments with acute ischaemic stroke, and focuses on thrombolysis. The review includes initial management, recommended clinical, laboratory, and radiographic examinations. Appropriate general medical care, consisting of monitoring of oxygenation, fever, blood pressure, and blood glucose concentrations are examined. Criteria for thrombolysis with intravenous recombinant tissue plasminogen activator (rt-PA) are discussed. Complications of rt-PA therapy, such as haemorrhagic transformation and angio-oedema, are reviewed. An approach to management of rt-PA complications is outlined. Only a small percentage of acute ischaemic stroke patients meet criteria for rt-PA; therefore, alternative acute treatment strategies are also discussed. Acute medical and neurological complications in stroke patients are analysed, along with recommendations for treatment.

Prevention of Venous Thromboembolism, Recurrent Stroke, and Other Vascular Events After Acute Ischemic Stroke: The Role of Low-Molecular-Weight Heparin and Antiplatelet Therapy

Patients with stroke or transient ischemic attacks (TIAs) are at increased risk of vascular events, such as recurrent stroke or venous thromboembolism (VTE), and thus the secondary prevention of such events is an important element of managing these patients. Current guidelines recommend that patients with acute stroke, restricted mobility, and no contraindications to anticoagulants receive thromboprophylactic therapy with low-dose unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), or heparinoids to prevent VTE. This recommendation is based on clinical trial evidence that UFH is effective in reducing the incidence of deep vein thrombosis (DVT) after stroke. LMWHs have been shown to be at least as effective as UFH in preventing VTE, and offer advantages in terms of a more predictable anticoagulant effect, lower risk of bleeding, and ease of administration. However, adequately powered trials are needed to confirm their relative benefits and risks; the Prevention of VTE after Acute Ischemic Stroke with LMWH (PREVAIL) study with enoxaparin, currently in progress, should provide valuable information in this context. Antiplatelet therapy has been shown to be effective in preventing recurrent vascular events, as evidenced by the results of studies such as the Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events (CAPRIE) trial. In contrast, evidence for the efficacy of LMWH in this situation is contradictory. Given the potential benefits of LMWH in preventing VTE in stroke patients, a potential rationale exists for combination therapy with antiplatelet agents and LMWHs. Clinical trials with such combinations are warranted.

Emerging Strategies in the Prevention of Venous Thromboembolism in Hospitalized Medical Patients

Venous thromboembolism (VTE) remains a significant cause of morbidity and mortality in hospitalized patients with acute medical illness. The high prevalence of VTE in this patient population, its clinically silent nature, and associated morbidity and mortality indicate that prophylactic therapy is appropriate in those determined to be at increased risk. Unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) have been shown to reduce the incidence of VTE and are the primary therapies used for prophylaxis in these patients. Although both UFH and LMWH have received grade 1A recommendations for the prevention of VTE in at-risk medical patients in the 2004 American College of Chest Physicians consensus conference statements, LMWH has advantages over UFH in its once-daily dosing scheme, reduced incidence of major and minor bleeding events, and reduced incidence of heparin-induced thrombocytopenia. Fondaparinux is a novel antithrombotic agent characterized by specificity for factor Xa and a lack of platelet interaction. A recent clinical trial in hospitalized patients with acute medical illness found that fondaparinux significantly reduced the incidence of both VTE and fatal pulmonary embolism compared with placebo, without increased major bleeding. Despite the availability of effective thromboprophylactic therapies, VTE prophylaxis continues to be underutilized in hospitalized medical patients.

Prevention of venous thromboembolism after acute ischemic stroke

Venous thromboembolism (VTE) is a common complication after acute ischemic stroke. When screened by 125I fibrinogen scanning or venography, the incidence of deep-vein thrombosis (DVT) in stroke patients is comparable with that seen in patients undergoing hip or knee replacement. Most stroke patients have multiple risk factors for VTE, like advanced age, low Barthel Index severity score or hemiplegia. As pulmonary embolism is a major cause of death after acute stroke, the prevention of this complication is of crucial importance. Prospective trials have shown that both unfractionated heparin (UFH) and low molecular weight heparin (LMWH) are effective in reducing DVT and pulmonary embolism in stroke patients. Current guidelines recommend the use of these agents in stroke patients with risk factors for VTE. Some clinicians are concerned that the rate of intracranial bleeding associated with thromboprophylaxis may outweigh the benefit of prevention of VTE. Low-dose LMWH and UFH seem, however, safe in stroke patients. Higher doses clearly increase the risk of cerebral bleeding and should be avoided for prophylactic use. Both aspirin and mechanical prophylaxis are suboptimal to prevent VTE. Graduated compression stockings should be reserved to patients with a clear contraindication to antithrombotic agents.

Enoxaparin Versus Unfractionated Heparin in the Prevention of Venous Thromboembolism After Acute Ischemic Stroke: Rationale, Design, and Methods of an Open-Label, Randomized, Parallel-Group Multicenter Trial

BACKGROUND

Small sample size and methodologic limitations make it difficult to interpret and compare trials of low molecular-weight heparin (for example, enoxaparin) versus unfractionated heparin as prophylactic treatment for venous thromboembolism (VTE), that is, deep vein thrombosis and/or pulmonary embolism, in patients with acute ischemic stroke. This prospective, open-label, randomized, parallel-group, multicenter trial is designed to evaluate the efficacy and safety of enoxaparin versus unfractionated heparin for the prevention of VTE after acute ischemic stroke.

METHODS

Approximately 1760 patients with the diagnosis of acute ischemic stroke accompanied by leg paralysis will be randomly assigned (1:1) within 48 hours of stroke symptoms to receive enoxaparin (40 mg subcutaneously) once daily or unfractionated heparin (5000 U subcutaneously) every 12 hours for 10 +/- 4 days. Contrast venography will be used to evaluate asymptomatic patients after treatment for deep vein thrombosis. In addition, diagnostic algorithms will be used to objectively confirm or rule out VTE events for patients in whom upper- or lower-extremity deep vein thrombosis/pulmonary embolism is suggested.

RESULTS

The primary efficacy end point measure will be the cumulative occurrence of documented VTE during the initial treatment period. Secondary end points are VTE incidence; neurologic outcome at days 30, 60, and 90; safety; and health care resource use during initial hospitalization and during the 30- and 90-day follow-up periods.

CONCLUSIONS

This study will provide clinical and health economic data regarding the use of enoxaparin as primary prophylactic treatment of VTE in patients who have had an acute ischemic stroke.

Low-molecular-weight heparins or heparinoids versus standard unfractionated heparin for acute ischaemic stroke

BACKGROUND

Low-molecular-weight heparins and heparinoids are anticoagulants that may be associated with lower risks of haemorrhage and more powerful antithrombotic (anti-clotting) effects than standard unfractionated heparin.

OBJECTIVES

The objective of this review was to compare the effects of low-molecular-weight heparins or heparinoids with those of unfractionated heparin in people with acute, confirmed or presumed, ischaemic stroke (sudden blockage of an artery carrying blood to the brain).

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (last searched November 2003). In addition we searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2003), MEDLINE (1966 to October 2003) and EMBASE (1980 to October 2003). For previous versions of this review we searched MedStrategy (1995) and also contacted pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing heparinoids or low-molecular-weight heparins with standard unfractionated heparin in people with acute ischaemic stroke. Only trials where treatment was started within 14 days of stroke onset were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected studies for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Six trials involving 740 people were included. Four trials compared a heparinoid (danaparoid), one trial compared a low-molecular-weight heparin (enoxaparin), and one trial compared an unspecified low-molecular-weight heparin with standard unfractionated heparin. Allocation a to low-molecular-weight heparin or heparinoid was associated with a significant reduction in the odds of deep vein thrombosis (Peto odds ratio 0.52, 95% confidence interval 0.56 to 0.79). However, the number of more major events (pulmonary embolism, death, intra-cranial or extra-cranial haemorrhage) was too small to provide a reliable estimate of more important benefits and risks. No information was reported for recurrent stroke or functional outcome.

AUTHORS' CONCLUSIONS

Treatment with a low-molecular-weight heparin or heparinoid after acute ischaemic stroke appears to decrease the occurrence of deep vein thrombosis compared to standard unfractionated heparin, but there are too few data to provide reliable information on their effects on other important outcomes, including death and intracranial haemorrhage.

Frequency and risk factors for spontaneous hemorrhagic transformation of cerebral infarction

OBJECTIVE

Hemorrhagic transformation of cerebral infarction (HTI) occurs spontaneously but its frequency and risk factors are uncertain with mixed results in previous studies. We aimed to determine the overall frequency of and risk factors for HTI.

METHODS

We performed a systematic review according to Cochrane Collaboration methods of published reports of HTI with reliable, systematic follow-up with computed tomography or magnetic resonance imaging.

RESULTS

In all, 28 observational studies and 19 randomized controlled trials in stroke were identified that included follow-up imaging data. Problems with inconsistent definitions or small and biased patient populations limited detailed interpretation. The overall frequency of any HTI in untreated patients was 8.5% (95% confidence interval 7%-10%). Severe HTI (i.e., HTI accompanied by neurologic deterioration or parenchymal hematoma formation) occurred in 1.5% (95% confidence interval 0.8%-2.2%). The frequency of HTI increased markedly with increasing use of antithrombotic or thrombolytic drugs. Magnetic resonance imaging detected more HTI than did computed tomography. The published data were generally inadequate to undertake more detailed analysis of risk factors. However, in the 8 studies that did provide the information, HTI was associated with large infarcts, mass effect, hypodensity observed early after the stroke, and age older than 70 years, but not hypertension or cardioembolic stroke.

CONCLUSIONS

Severe HTI is uncommon in patients not receiving antithrombotic or thrombolytic agents. The methods used to assess the frequency of and risk factors for HTI, particularly a standard of definitions in future prospective studies, could be improved.

The effectiveness of anticoagulant and antiplatelet agents in preventing venous thromboembolism during stroke rehabilitation: a historical cohort study

OBJECTIVE

To determine the effectiveness of anticoagulant and antiplatelet agents in preventing venous thromboembolism (VTE) during stroke rehabilitation.

DESIGN

Historical cohort study.

SETTING

Acute inpatient rehabilitation hospital.

PARTICIPANTS

Consecutive patients (N=1506) with ischemic and hemorrhagic stroke admitted for rehabilitation.

INTERVENTIONS

Documented use of anticoagulants (warfarin or anticoagulant doses of heparin), heparin in prophylactic doses, and antiplatelet agents.

MAIN OUTCOME MEASURE

Occurrence of deep vein thrombosis detected by ultrasound or venography or pulmonary embolism detected by ventilation perfusion scan, spiral computed tomography, or pulmonary angiography.

RESULTS

Fifty-eight VTE events occurred (3.9% incidence or 1.36 events per 1000 patient days), with higher risk in patients with severe stroke. Only therapeutic anticoagulation had a statistically significant protective effect for VTE risk in univariate analysis (odds ratio [OR]=.44; 95% confidence interval [CI],.20-.98). After adjusting for multiple medication use and other factors, including age, stroke onset to admission interval, length of rehabilitation stay, cause of stroke, and admission National Institutes of Health Stroke Scale score, therapeutic anticoagulation gave strong protection against VTE (OR=.37; 95% CI,.15-.88), followed by heparin (OR=.48; 95% CI,.23-.98) but not by antiplatelet agents (OR=.79; 95% CI,.40-1.57). No medications were associated with significant bleeding complications.

CONCLUSIONS

Use of therapeutic anticoagulants or prophylactic heparin prevented VTE in stroke patients during inpatient rehabilitation.

Quality of the stroke rehabilitation research

The Stroke Rehabilitation Evidence-Based Review revealed a wide range of quality scores across primary studies. The aim of this section is to determine what differences there are across studies and to provide a detailed examination of methodological issues in the stroke rehabilitation literature. Methodology of each article was assessed using the Physiotherapy Evidence Database (PEDro) quality scale. Mean PEDro scores and percentage of studies meeting individual PEDro criteria were determined for all studies, for therapy-based studies only, and for drug-based studies only. It was noted that the stroke rehabilitation literature lacked rigor in the area of concealed allocation, blinding of the assessor, and intention-to-treat analysis. Investigation of the methodological quality of stroke rehabilitation literature emphasizes the need for improved treatment protocols, taking into account previous deficits, during research.

An evidence-based review of stroke rehabilitation

A comprehensive evidence-based review of stroke rehabilitation was created to be an up-to-date review of the current evidence in stroke rehabilitation and to provide specific conclusions based on evidence that could be used to help direct stroke care at the bedside and at home. A literature search using multiple data-bases was used to identify all trials from 1968 to 2001. Methodological quality of the individual randomized controlled trials was assessed using the Physiotherapy Evidence Database (PEDro) quality assessment scale. A five-stage level-of-evidence approach was used to determine the best practice in stroke rehabilitation. Over 403 treatment-based articles investigating of various areas of stroke rehabilitation were identified. This included 272 randomized controlled trials.

Prophylactic Anticoagulation for Venous Thromboembolic Disease in Geriatric Patients

Venous thromboembolic disease (VTED) occurs commonly in geriatric medical patients, causing significant morbidity and mortality. Although VTED is preventable, prophylactic anticoagulation is underused. Awareness of the clinical risk factors that contribute to VTED in the elderly is essential for identifying candidates for prophylaxis. Iatrogenic risk factors include venous catheterization, transvenous pacemaker placement, hormone replacement therapy, and immobilization or prolonged bed rest. Medical conditions associated with increased risk include a previous episode of VTED, myocardial infarction, heart failure, severe lung disease, cancer, and neurological conditions associated with paresis. Obstacles to the widespread usage of VTED prophylaxis in geriatric medical patients include the clinically silent nature of VTED, underestimation of the risk and clinical effect of VTED in this population, and concerns about the cost and safety of anticoagulant therapy in this population. Clinical practice guidelines devised specifically for geriatric medical patients facilitate rational use of thromboprophylaxis in this population. The safety, efficacy, cost-effectiveness, and convenience of low-molecular-weight heparins for thromboprophylaxis are reflected in their increasing prominence in clinical practice guidelines and clinical use.

Low-molecular-weight heparins and heparinoids in acute ischemic stroke : a meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

Low-molecular-weight heparins and heparinoids (LMWHs) are superior to unfractionated heparin in the prevention and treatment of venous thromboembolism and acute coronary syndromes. We performed a systematic review of randomized controlled trials (RCTs) to examine the safety and efficacy of LMWH in acute ischemic stroke.

METHODS

Randomized, controlled, and nonconfounded trials of LMWH in acute ischemic stroke were identified from the Cochrane Library (version 2, 1999), previous systematic reviews, and a review of publication quality relating to acute stroke trials. The authors each independently extracted data by treatment group and assessed trial quality using Cochrane Collaboration criteria.

RESULTS

Eleven completed RCTs involving 3048 patients were identified; data were available from 10 of these. Four trials explicitly excluded patients with presumed cardioembolic stroke. Treatment with LMWH was associated with significant reductions in prospectively identified deep vein thrombosis (OR 0.27, 95% CI 0.08 to 0.96) and symptomatic pulmonary embolism (OR 0.34, 95% CI 0.17 to 0.69) and with increased major extracranial hemorrhage (OR 2.17, 95% 1.10 to 4.28). Nonsignificant increases in end-of-treatment (OR 1.20, 95% CI 0.86 to 1.69) and end-of-trial (OR 1.05, 95% CI 0.83 to 1.32) case fatality and symptomatic intracranial hemorrhage (OR 1.77, 95% CI 0. 95 to 3.31) were observed. End-of-trial death and disability was nonsignificantly reduced (OR 0.87, 95% CI 0.72 to 1.06).

CONCLUSIONS

++LMWHs reduce venous thromboembolic events in patients with acute ischemic stroke and increase the risk of extracranial bleeding. A nonsignificant reduction in combined death and disability and nonsignificant increases in case fatality and symptomatic intracranial hemorrhage were also observed. On the basis of the current evidence, LMWH should not be used in the routine management of patients with ischemic stroke.

Prevention of venous thromboembolism

Venous thromboembolism is the most common cause of preventable death among hospitalised patients. Systematic prophylaxis with antithrombotic agents in patients at risk for venous thromboembolism is the most effective approach to reduce morbidity and mortality. Despite this evidence, antithrombotic prophylaxis is still underused, due to the underestimation of incidence of venous thromboembolism and to the unjustified fear of bleeding complications. Both the characteristics of the individual patient and the clinical setting contribute to the definition of the risk for venous thromboembolism. Patient-related risk factors include clinical and molecular abnormalities. The grade of risk for venous thromboembolism is defined better by the clinical setting than by the patient characteristics. Prophylactic studies have been extensively carried out in surgical patients and, only more recently, in medical patients. Prophylactic methods include pharmacological agents, such as heparin, low molecular weight heparins, warfarin, and hirudin, as well as mechanical methods such as compression stockings and intermittent pneumatic compression.

Current status of neuroprotection trials for traumatic brain injury: lessons from animal models and clinical studies

Laboratory studies have identified numerous potential therapeutic interventions that might have clinical application for the treatment of human traumatic brain injury. Many of these therapies have progressed into human clinical trials in severe traumatic brain injury. Numerous trials have been completed, and many others have been prematurely terminated or are currently in various phases of testing. The results of the completed Phase III trials have been generally disappointing, compared with the expectations produced by the successes of these interventions in animal laboratory studies. In this review, we summarize the current status of human traumatic brain injury clinical trials, as well as the animal laboratory studies that led to some of these trials. We summarize criteria for conducting clinical trials in severe traumatic brain injury, with suggestions for future improvements. We also attempt to identify factors that might contribute to the discrepancies between animal and human trials, and we propose recommendations that could help investigators avoid certain pitfalls in future clinical trials in traumatic brain injury.