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Biomedical subjects

C Counsell

Publications and source records attributed to C Counsell.

At least 19 recordsLinked to original sources
PubMed2005

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.

Anticoagulants↗
PubMed2004

Anticoagulants for acute ischaemic stroke.

BACKGROUND: Most ischaemic strokes are caused by blood clots blocking an artery in the brain. Clot prevention with anticoagulant therapy could have a significant impact on patient survival, disability and stroke recurrence. OBJECTIVES: The objective of this review was to assess the effect of anticoagulant therapy versus control in the early treatment of patients with acute ischaemic stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register (last searched 30 October 2003). For previous updates 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 patients with acute presumed or confirmed ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Twenty-two trials involving 23,547 patients were included. The quality of the trials varied considerably. The anticoagulants tested were standard unfractionated heparin, low-molecular-weight heparins, heparinoids, oral anticoagulants, and thrombin inhibitors. Based on nine trials (22,570 patients) there was no evidence that anticoagulant therapy reduced the odds of death from all causes (odds ratio (OR) = 1.05, 95% confidence interval (CI) 0.98 to 1.12) at the end of follow-up. Similarly, based on six trials (21,966 patients), there was no evidence that anticoagulants reduced the odds of being dead or dependent at the end of follow-up (OR = 0.99; 95% CI 0.93 to 1.04). Although anticoagulant therapy was associated with about 9 fewer recurrent ischaemic strokes per 1000 patients treated (OR = 0.76; 95% CI 0.65 to 0.88), it was also associated with a similar sized 9 per 1000 increase in symptomatic intracranial haemorrhages (OR = 2.52; 95% CI 1.92 to 3.30). Similarly, anticoagulants avoided about 4 pulmonary emboli per 1000 (OR = 0.60, 95% CI 0.44 to 0.81), but this benefit was offset by an extra 9 major extracranial haemorrhages per 1000 (OR = 2.99; 95% CI 2.24 to 3.99). Sensitivity analyses did not identify a particular type of anticoagulant regimen or patient characteristic associated with net benefit. REVIEWERS' CONCLUSIONS: Immediate anticoagulant therapy in patients with acute ischaemic stroke is not associated with net short- or long-term benefit. The data from this review do not support the routine use of any type of anticoagulant in acute ischaemic stroke. People treated with anticoagulants had less chance of developing deep vein thrombosis (DVT) and pulmonary embolism (PE) following their stroke, but these sorts of blood clots are not very common, and may be prevented in other ways.

Anticoagulants↗
PubMed2004

Predicting functional outcome in acute stroke: comparison of a simple six variable model with other predictive systems and informal clinical prediction.

BACKGROUND: Statistical models that predict functional outcome after stroke using six simple variables (SSV) have recently been developed and validated. OBJECTIVE: To compare the accuracy of these models with other simple ways of predicting outcome soon after stroke. METHODS: The SSV model for being alive and independent (modified Rankin score < or =2) six months or one year after stroke was compared with predictions based on a model that included only age and Oxford community stroke project classification, with predictions based on conscious level and urinary continence, and with informal clinical predictions made by clinicians interested in stroke. Predictions were compared in an independent hospital based cohort of stroke patients using receiver operator characteristic (ROC) curves. RESULTS: The SSV model at six months had a significantly greater area under the curve (0.84) than the model with only age and stroke classification (0.75). Predictions based on conscious level and urinary continence were no better than those of the SSV model and were unable to predict subjects with a high probability of good outcome. The sensitivity and specificity for informal clinical predictions at one year lay on or below the SSV model curve, implying that the SSV model was at least as good as clinical predictions. CONCLUSIONS: The SSV models performed as well as or better than other simple predictive systems. These models will be useful in epidemiological studies but should not be used to guide clinical management until their impact on patient care and outcome has been evaluated.

Activities of Daily Living↗
PubMed2001

Systematic review of prognostic models in patients with acute stroke.

Prognostic models in stroke may be useful in clinical practice and research. We systematically reviewed the methodology and results of studies that have identified independent predictors of survival, independence in activities of daily living, and getting home in patients with acute stroke. Eligible studies (published in full in English) included at least 100 patients in whom at least 3 predictor variables were assessed within 30 days of stroke onset and who were followed up for at least 30 days. We recorded 25 indicators of the validity and practicality of each model and identified variables that were consistent independent predictors of each outcome. Eighty-three separate prognostic models were found but most had potentially serious deficiencies in internal and statistical validity, many had limited generalisability, and none had been adequately validated. Only 4 studies met 8 simple quality criteria. Over 150 different predictor variables have been analysed but most were assessed in only 1 or 2 models. None of the existing prognostic models have been sufficiently well developed and validated to be useful in either clinical practice or research. Better quality models must be produced to enable, for example, adequate case-mix correction when comparing outcome among different groups of stroke patients.

Humans↗
PubMed2001

Uterine artery malformation as a hidden cause of severe uterine bleeding. A case report.

BACKGROUND: Uterine artery malformations are rare, life-threatening conditions. Clinical suspicion is essential for a prompt diagnosis and treatment. CASE: A 29-year-old woman was evaluated for severe uterine bleeding that started abruptly two weeks after elective termination of pregnancy. She underwent dilatation and curettage of the uterine cavity for retained products of conception. The patient presented to the emergency room two weeks later with abrupt onset of profuse vaginal bleeding that would spontaneously subside. Magnetic resonance angiography revealed a left uterine artery malformation that was successfully embolized. CONCLUSION: Uterine artery malformations should be suspected when heavy vaginal bleeding occurs in spite of medical or surgical treatment.

Abortion, Induced↗
PubMed2000

Anticoagulants for acute ischaemic stroke.

BACKGROUND: Most ischaemic strokes are caused by blood clots blocking an artery in the brain. Clot prevention with anticoagulant therapy could have a significant impact on patient survival, disability and recurrence of stroke. OBJECTIVES: The objective of this review was to assess the effect of anticoagulant therapy in the early treatment of patients with acute ischaemic stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register (most recent search: March 1999) and consulted MedStrategy (1995). We also contacted drug companies. SELECTION CRITERIA: Randomised trials comparing early anticoagulant therapy (started within two weeks of stroke onset) with control in patients with acute presumed or confirmed ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Twenty-one trials involving 23,427 patients were included. The quality of the trials varied considerably. The anticoagulants tested were standard unfractionated heparin, low-molecular-weight heparins, heparinoids, oral anticoagulants, and thrombin inhibitors. Based on eight trials (22,450 patients) there was no evidence that anticoagulant therapy reduced the odds of death from all causes (odds ratio 1.05, 95% confidence intervals 0.98-1.12). Similarly, based on five trials (21, 846 patients), there was no evidence that anticoagulants reduced the odds of being dead or dependent at the end of follow-up (odds ratio 0.99, 95% confidence intervals 0.94-1.05). Although anticoagulant therapy was associated with about 9 fewer recurrent ischaemic strokes per 1000 patients treated, it was also associated with a similar sized 9 per 1000 increase in symptomatic intracranial haemorrhages. Similarly, anticoagulants avoided about 4 pulmonary emboli per 1000, but this benefit was offset by an extra 9 major extracranial haemorrhages per 1000. Sensitivity analyses did not identify a particular type of anticoagulant regimen or patient characteristic associated with net benefit. REVIEWER'S CONCLUSIONS: Immediate anticoagulant therapy in patients with acute ischaemic stroke is not associated with net short- or long-term benefit. The data from this review do not support the routine use of any type of anticoagulant in acute ischaemic stroke.

Anticoagulants↗
PubMed2000

Antiplatelet therapy for acute ischaemic stroke.

BACKGROUND: In patients with acute ischaemic stroke, platelets become activated. Antiplatelet therapy might reduce the volume of brain damaged by ischaemia and reduce the risk of early recurrent ischaemic stroke. This might reduce the risk of early death and improve long-term outcome in survivors. However, antiplatelet therapy might also increase the risk of fatal or disabling intracranial haemorrhage. OBJECTIVES: The aim of this review is to assess the net result of antiplatelet therapy in acute ischaemic stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register (most recent date of search March 1999), the register of trials held by the Antiplatelet Trialists' Collaboration, and MedStrategy (1995). We also contacted relevant pharmaceutical companies. SELECTION CRITERIA: Randomised trials comparing antiplatelet therapy started within 14 days of the stroke with control in patients with definite or presumed ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied the inclusion criteria and assessed trial quality, and for the included trials, extracted and cross-checked the data. MAIN RESULTS: Eight trials involving 41,325 patients were included. Two trials testing aspirin 160 to 300 mg once daily started within 48 hours of onset contributed 98% of the data. The maximum follow-up was six months. With treatment, there was a significant decrease in death or dependency at the end of follow-up (OR = 0.94; 95% CI 0.91 - 0.98). In absolute terms, 13 more patients were alive and independent at the end of follow-up for every 1000 patients treated. Furthermore, treatment increased the odds of making a complete recovery from the stroke (OR = 1.06; 95% CI 1.01 - 1.11). In absolute terms, 10 patients made a complete recovery for every 1000 patients treated. Antiplatelet therapy was associated with a small but definite excess of 2 symptomatic intracranial haemorrhages for every 1000 patients treated, but this was more than offset by a reduction of 7 recurrent ischaemic strokes for every 1000 patients treated. REVIEWER'S CONCLUSIONS: Antiplatelet therapy with aspirin 160 to 300 mg daily, given orally (or per rectum in patients who cannot swallow), and started within 48 hours of onset of presumed ischaemic stroke reduces the risk of early recurrent ischaemic stroke without a major risk of early haemorrhagic complications and improves long-term outcome.

Brain Ischemia↗
PubMed2000

Patches of different types for carotid patch angioplasty.

BACKGROUND: Some surgeons who use carotid patching favour using the saphenous vein, whilst others favour synthetic materials. OBJECTIVES: The objective of this review was to assess the effect of different materials for carotid patch angioplasty. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register, Medline (1966 to 1995), Embase (1980 to 1995) and Index to scientific and technical proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular and Endovascular Surgery (1987 to 1995) and World Journal of Surgery (1978 to 1995). SELECTION CRITERIA: Randomised trials comparing one type of carotid patch with another for carotid endarterectomy. DATA COLLECTION AND ANALYSIS: One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed. MAIN RESULTS: Three trials involving 326 operations were included. The trials compared saphenous vein patches with synthetic polytetrafluroethylene patches. Allocation was not adequately concealed in two trials, and only one followed-up patients until hospital discharge. Intention-to-treat analysis was only possible for the latter trial. In all trials a patient could be randomised twice and have each carotid artery randomised to different treatment groups. One trial was excluded from the analyses of death and any stroke because it was not possible to clarify how many patients, rather than arteries, were allocated to each treatment. There were too few events to determine whether there was any difference between the patch materials for perioperative stroke, death and arterial complications. During longterm follow-up for more than one year, no difference was shown between the two types of patch for the risk of stroke, death, or arterial restenosis. However, the number of events was small. Based on 236 patients in two trials, there were significantly fewer pseudoaneurysms associated with synthetic patches (odds ratio 0.15, 95% confidence interval 0.05 to 0.44). REVIEWER'S CONCLUSIONS: There is not enough evidence to differentiate between venous and synthetic patches in carotid endarterectomy.

Blood Vessel Prosthesis↗
PubMed2000

Fibrinogen depleting agents for acute ischaemic stroke.

BACKGROUND: Fibrinogen depleting agents reduce fibrinogen in blood plasma, reduce blood viscosity and hence increase blood flow. This may help remove the blood clot blocking the artery and re-establish blood flow to the affected area of the brain after an ischaemic stroke. The risk of haemorrhage may be less than with thrombolytic agents. OBJECTIVES: The objective of this review was to assess the effect of fibrinogen depleting agents in people with acute ischaemic stroke. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register, Embase (to January 1996) and the Index of scientific and technical proceedings (1982 to 1996). We handsearched 10 Chinese journals and the proceedings of the 4th Chinese Stroke Conference (1995). We contacted Chinese and Japanese researchers, and drug companies. SELECTION CRITERIA: Randomised and quasi-randomised trials of fibrinogen depleting agents started within 14 days of stroke onset, compared with control in patients with definite or possible ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied the inclusion criteria, assessed trial quality and extracted the data. MAIN RESULTS: Three trials involving 182 patients were included. All trials tested ancrod. Allocation concealment was adequate in two trials. Fibrinolytic therapy appeared to reduce the number of deaths during the scheduled treatment period (odds ratio 0.33, 95% confidence interval 0.13 to 0.85). There was no difference in death from all causes at the end of follow-up (odds ratio 0.57, 95% confidence interval 0.27 to 1.23). The risk of haemorrhage appeared to be small, but there were too few data to be conclusive. One trial in 132 people showed a statistically non-significant decrease in the odds of being dead or disabled at the end of follow-up (odds ratio 0.52, 95% confidence interval 0.26 to 1.03). REVIEWER'S CONCLUSIONS: Although ancrod appears to be promising, it is not possible to draw reliable conclusions from the available data.

Ancrod↗
PubMed2000

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

BACKGROUND: Low molecular weight heparins and heparinoids may be associated with lower risks of haemorrhage and more powerful antithrombotic 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. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register and MedStrategy (1995). We also contacted pharmaceutical companies. Date of most recent search: April 1999. 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: Five trials involving 705 people were included. Four trials compared a heparinoid (danaparoid), and one compared a low molecular weight heparin (enoxaparin), with standard unfractionated heparin. Overall, 55/414 (13%) of the patients allocated danaparoid or enoxaparin had deep vein thrombosis compared with 65/291 (22%) of those allocated unfractionated heparin. This reduction was significant (odds ratio 0.52, 95% confidence interval 0.56 - 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 in survivors. REVIEWER'S CONCLUSIONS: Low molecular weight heparin or heparinoid appear 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 effect on other important outcomes, including death and intracranial haemorrhage.

Anticoagulants↗
PubMed2000

Local versus general anaesthesia for carotid endarterectomy.

BACKGROUND: Carotid endarterectomy reduces the risk of stroke in people with recently symptomatic, severe carotid artery stenosis. However, there are significant perioperative risks which may be lessened by performing the operation under local rather than general anaesthetic. OBJECTIVES: The objective of this review was to assess the effect of endarterectomy under local compared with general anaesthetic. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register, Medline (1966 to 1995), Embase (1980 to 1995), and Index to Scientific and Technical Proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular Surgery (1988 to 1995) and World Journal of Surgery (1978 to 1995). Reference lists of articles were searched. SELECTION CRITERIA: Randomised trials and non-randomised studies comparing carotid endarterectomy under local versus general anaesthetic. DATA COLLECTION AND ANALYSIS: One reviewer selected studies for inclusion and another independently checked the decisions. Two reviewers assessed trial quality and independently extracted the data. MAIN RESULTS: Three randomised trials involving 143 patients, and 17 non-randomised studies involving about 5970 patients were included. The methodological quality of the randomised trials was questionable. Two of the non-randomised studies were prospective and 12 reported on a consecutive series of patients. In nine non-randomised studies the number of patients, as opposed to the number of arteries, was unclear. There were insufficient data to enable conclusions to be drawn from the randomised trials. In 15 non-randomised studies, no significant difference was shown between local and general anaesthetic in deaths within 30 days of operation (odds ratio 0.61, 95% confidence interval 0.32 to 1.16). Non-randomised studies showed that local anaesthetic was associated with a significant reduction in the odds of stroke (15 studies), stroke or death (14 studies), myocardial infarction (12 studies), and pulmonary complications (five studies), within 30 days of the operation. Patient and surgeon satisfaction were not reported in any study. REVIEWER'S CONCLUSIONS: There is not enough evidence from randomised trials comparing carotid endarterectomy performed under local as opposed to general anaesthetic. Non-randomised studies suggest potential benefits with local anaesthetic. However these studies are likely to be significantly biased.

Anesthesia, General↗
PubMed2000

Patch angioplasty versus primary closure for carotid endarterectomy.

BACKGROUND: Carotid patch angioplasty (with either a venous or a synthetic patch) may reduce the risk of carotid artery restenosis and subsequent ischaemic stroke. OBJECTIVES: The objective of this review was to assess the effect of routine or selective carotid patch angioplasty compared to carotid endarterectomy with primary closure. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register, Medline (1966 to 1995), Embase (1980 to 1995) and Index to Scientific and Technical Proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular and Endovascular Surgery (1987 to 1995) and World Journal of Surgery (1978 to 1995). SELECTION CRITERIA: Randomised trials comparing carotid patch angioplasty with primary closure in any patients undergoing carotid endarterectomy. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed eligibility, trial quality and extracted the data. MAIN RESULTS: Six trials involving 794 patients and 882 operations were included. The quality of trials was generally poor. Follow-up varied from hospital discharge to five years. Carotid patch angioplasty showed a reduction in the risk of stroke of any type, ipsilateral stroke, and stroke or death, during the perioperative period and longterm follow-up. However, data were not available from all trials, the number of events was small and there was significant loss to follow-up. Patching appeared to reduce the risk of perioperative arterial occlusion (six trials, odds ratio 0.17, 95% confidence interval 0.06 to 0.46). Patching was also associated with decreased restenosis during longterm follow-up in five trials, (odds ratio 0.32, 95% confidence interval 0.19 to 0.53). However, these results are uncertain because of loss to follow-up and the small number of events. Very few arterial complications, including haemorrhage, infection, cranial nerve palsies and pseudo-aneurysm formation were recorded with either patch or primary closure. REVIEWER'S CONCLUSIONS: Limited evidence suggests that carotid patch angioplasty may lower the risk of perioperative arterial occlusion and restenosis. It is unclear whether this reduces the risk of death or stroke.

Blood Vessel Prosthesis↗
PubMed2000

Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting).

BACKGROUND: Temporary interruption of blood flow during carotid endarterectomy can be avoided by using a shunt across the clamped section of the carotid artery. This may improve outcome. OBJECTIVES: The objective of this review was to assess the effect of routine versus selective shunting during carotid endarterectomy, and to assess the best method for selecting patients for shunting. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register, Medline (1966 to 1994), Embase (1980 to 1995) and Index to Scientific and Technical Proceedings (1980 to 1994). We handsearched Annals of Surgery (1981 to 1995), British Journal of Surgery (1985 to 1995), European Journal of Vascular Surgery (1988 to 1995) and World Journal of Surgery (1978 to 1995). SELECTION CRITERIA: Randomised and quasi-randomised trials of routine shunting compared with no shunting, and trials that compared different shunting policies in patients undergoing carotid endarterectomy. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied the inclusion criteria. The data were extracted by one reviewer and double-checked. Trial quality was assessed. MAIN RESULTS: Three trials were included. Two trials involving 590 patients compared routine shunting with no shunting. The other trial involving 131 patients compared shunting with a combination of electroencephalographic and carotid pressure measurement, with shunting by carotid pressure measurement alone. Allocation was adequately concealed in one trial, and one trial was quasi-randomised. Analysis was by intention-to-treat where possible. For routine versus no shunting, there was no significant difference in the rate of all stroke, ipsilateral stroke or death up to 30 days after surgery, although data were limited. There was no significant difference between the risk of ipsilateral stroke in patients selected for shunting with the combination of electroencephalographic and carotid pressure assessment compared to pressure assessment alone, although again the data were limited. REVIEWER'S CONCLUSIONS: The data presently available are too limited to either support or refute the use of routine or selective shunting in carotid endarterectomy. Large scale randomized trials using no shunting as the control group are required. No one method of monitoring in selective shunting has been shown to produce better outcomes.

Arteriovenous Shunt, Surgical↗
PubMed2000

Anticoagulants for preventing recurrence following ischaemic stroke or transient ischaemic attack.

BACKGROUND: After a first stroke, further vascular events (especially myocardial infarction and recurrent stroke) are common and often fatal. OBJECTIVES: The objective of this review was to assess the effect of prolonged anticoagulant therapy following presumed non-embolic ischaemic stroke or transient ischaemic attack. SEARCH STRATEGY: We searched the Cochrane Stroke Group trials register. We contacted companies marketing anticoagulant agents. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing anticoagulant therapy, for at least one month, with control in people with previous non-embolic presumed ischaemic stroke or transient ischaemic attack. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Nine trials involving 1214 patients were included. The quality of all trials was poor. All pre-dated routine computerised tomography scanning and use of the International Normalised Ratio to monitor anticoagulation. Anticoagulant therapy did not significantly reduce the odds of death or dependency (two trials, odds ratio 0.83, 95% confidence interval 0.52 to 1.34). Death from any cause (odds ratio 0.95, 95% confidence interval 0.72 to 1.23), and death from vascular causes (odds ratio 0.86, 95% confidence interval 0.66 to 1.13) were not significantly different between treatment and control across all nine trials. Anticoagulant therapy did not reduce the risk of recurrent stroke (odds ratio 0.79, 95% confidence interval 0.56 to 1.13). However, fatal intracranial haemorrhage increased (odds ratio 2.54, 95% confidence interval 1.19 to 5.45), as did major extracranial haemorrhage (odds ratio 4.87, 95% confidence interval 2.50 to 9.49). This means anticoagulant therapy caused 11 additional fatal intracranial haemorrhages and 25 additional major extracranial haemorrhages per year for every 1000 patients given anticoagulant therapy. REVIEWER'S CONCLUSIONS: There appears to be no clear benefit from long-term anticoagulant therapy in people with non-embolic presumed ischaemic stroke or transient ischaemic attack. There appears to be a significant bleeding risk associated with anticoagulant therapy.

Anticoagulants↗
PubMed2000

Indications for early aspirin use in acute ischemic stroke : A combined analysis of 40 000 randomized patients from the chinese acute stroke trial and the international stroke trial. On behalf of the CAST and IST collaborative groups.

BACKGROUND AND PURPOSE: Long-term daily aspirin is of benefit in the years after ischemic stroke, and 2 large randomized trials (the Chinese Acute Stroke Trial [CAST] and the International Stroke Trial [IST]), with 20 000 patients in each, have shown that starting daily aspirin promptly in patients with suspected acute ischemic stroke also reduces the immediate risk of further stroke or death in hospital and the overall risk of death or dependency. However, some uncertainty remains about the effects of early aspirin in particular categories of patient with acute stroke. METHODS: To assess the balance of benefits and risks of aspirin in particular categories of patient with acute stroke (eg, the elderly, those without a CT scan, or those with atrial fibrillation), a prospectively planned meta-analysis is presented of the data from 40 000 individual patients from both trials on events that occurred in the hospital during the scheduled treatment period (4 weeks in CAST, 2 weeks in IST), with 10 characteristics used to define 28 subgroups. This represents 99% of the worldwide evidence from randomized trials. RESULTS: There was a highly significant reduction of 7 per 1000 (SD 1) in recurrent ischemic stroke (320 [1.6%] aspirin versus 457 [2. 3%] control, 2P<0.000001) and a less clearly significant reduction of 4 (SD 2) per 1000 in death without further stroke (5.0% versus 5. 4%, 2P=0.05). Against these benefits, there was an increase of 2 (SD 1) per 1000 in hemorrhagic stroke or hemorrhagic transformation of the original infarct (1.0% versus 0.8%, 2P=0.07) and no apparent effect on further stroke of unknown cause (0.9% versus 0.9%). In total, therefore, there was a net decrease of 9 (SD 3) per 1000 in the overall risk of further stroke or death in hospital (8.2% versus 9.1%, 2P=0.001). For the reduction of one third in recurrent ischemic stroke, subgroup-specific analyses found no significant heterogeneity of the proportional benefit of aspirin (chi(2)(18)=20. 9, NS), even though the overall treatment effect (chi(2)(1)=24.8, 2P<0.000001) was sufficiently large for such subgroup analyses to be statistically informative. The absolute risk among control patients was similar in all 28 subgroups, so the absolute reduction of approximately 7 per 1000 in recurrent ischemic stroke does not differ substantially with respect to age, sex, level of consciousness, atrial fibrillation, CT findings, blood pressure, stroke subtype, or concomitant heparin use. There was no good evidence that the apparent decrease of approximately 4 per 1000 in death without further stroke was reversed in any subgroup or that in any subgroup the increase in hemorrhagic stroke was much larger than the overall average of approximately 2 per 1000. Finally, there was no significant heterogeneity between the reductions in the composite outcome of any further stroke or death (chi(2)(18)=16.5, NS). Among the 9000 patients (22%) randomized without a prior CT scan, aspirin appeared to be of net benefit with no unusual excess of hemorrhagic stroke; moreover, even among the 800 (2%) who had inadvertently been randomized after a hemorrhagic stroke, there was no evidence of net hazard (further stroke or death, 63 aspirin versus 67 control). CONCLUSIONS: Early aspirin is of benefit for a wide range of patients, and its prompt use should be routinely considered for all patients with suspected acute ischemic stroke, mainly to reduce the risk of early recurrence.

Acute Disease↗
PubMed1999

Barriers to participation in randomised controlled trials: a systematic review.

METHOD: A systematic review of three bibliographic databases from 1986 to 1996 identified 78 papers reporting barriers to recruitment of clinicians and patients to randomised controlled trials. RESULTS: Clinician barriers included: time constraints, lack of staff and training, worry about the impact on the doctor-patient relationship, concern for patients, loss of professional autonomy, difficulty with the consent procedure, lack of rewards and recognition, and an insufficiently interesting question. Patient barriers included: additional demands of the trial, patient preferences, worry caused by uncertainty, and concerns about information and consent. CONCLUSIONS: To overcome barriers to clinician recruitment, the trial should address an important research question and the protocol and data collection should be as straightforward as possible. The demands on clinicians and patients should be kept to a minimum. Dedicated research staff may be required to support clinical staff and patients. The recruitment aspects of a randomised controlled trial should be carefully planned and piloted. Further work is needed to quantify the extent of problems associated with clinician and patient participation, and proper evaluation is required of strategies to overcome barriers.

Data Collection↗