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Biomedical subjects

P Sandercock

Publications and source records attributed to P Sandercock.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Antithrombotic treatment in acute ischemia stroke].

Antithrombotic drugs (especially heparin and aspirin) are widely used to treat patients during the acute phase of ischemic stroke, yet there is no evidence of any beneficial effect on the course of the disease. Although these drugs can reduce the risk of such complications as deep venous thrombosis and, possibly, the number of recurrences of stroke, they can also give rise to systemic or cerebral hemorrhage. Given the uncertainty about the efficacy and safety of antithrombotic drugs, and specifically about the risk/benefit ratio, large clinical trials are needed to determine the indications for their use in the management of acute ischemic stroke. We stress the importance, because of its magnitude, of the International Stroke Trial (IST), the results of which will be available in 1996.

Acute Disease↗
PubMed1994

Long-term risk of recurrent stroke after a first-ever stroke. The Oxfordshire Community Stroke Project.

BACKGROUND AND PURPOSE: There have been few community-based studies of long-term prognosis after acute stroke. This study aims to provide precise estimates of the absolute and relative risks of stroke recurrence in an unselected cohort of patients with a first-ever stroke. METHODS: Six hundred seventy-five patients were registered in a community-based stroke register (the Oxfordshire Community Stroke Project) and prospectively followed for up to 6.5 years. Their relative risk of recurrent stroke was calculated using age- and sex-specific incidence rates for first stroke in Oxfordshire. RESULTS: One hundred eighty recurrent episodes of stroke were identified, of which 135 were first recurrences. Given survival, the actuarial risk of suffering a recurrence was 30% (95% confidence interval, 20% to 39%) by 5 years, about nine times the risk of stroke in the general population. The risk was highest early after the first stroke: 13% (95% confidence interval, 10% to 16%) by 1 year, 15 times the risk in the general population. After the first year the average annual risk was about 4%. The risk of stroke recurrence did not appear to be related to age or pathological type of stroke. CONCLUSIONS: The absolute and relative risks of recurrent stroke are highest early after the first stroke but remain elevated for several years thereafter. Efforts at secondary prevention should be initiated as soon as possible and continued for several years to gain greatest benefit.

Actuarial Analysis↗
PubMed1994

Depressive disorders in long-term survivors of stroke. Associations with demographic and social factors, functional status, and brain lesion volume.

Sixty surviving patients from a community-based stroke register who had computerised tomography (CT) scan evidence of a single brain lesion were interviewed three to five years after their first ever stroke. Depression (DSM-III-R major depression, partially resolved major depression, and dysthymia) was present in 11 (18%) of the patients and was associated with impaired physical and cognitive functioning, greater age, residence in an institution, absence of a close personal relationship, and larger original brain lesion. Of these variables, only functional dependence (odds ratio 16.4; confidence interval 1.6-170), larger lesion volume (6.6; 1-50), and female sex (8; 1.1-56) remained significantly associated with depression after controlling for all other variables. We conclude that depression in long-term survivors of stroke has many of the same associations as depression in non-stroke elderly populations. Depression in long-term stroke survivors may also be associated with larger original brain lesions, although this requires confirmation in a prospective study.

Age Factors↗
PubMed1993

Collaborative worldwide overviews of randomized trials.

Formal overviews (or meta-analyses) are now widely accepted as the most reliable way to evaluate the evidence from several randomized controlled trials that have all assessed a particular form of therapy. If a limited amount of trial data has accumulated, overviews can be undertaken at a relatively simple level, assembling just summary data extracted from published reports. Such overviews are likely to be incomplete and biased and may (because of the restricted number of analyses that are possible) not answer all the clinically important questions that might be addressed. Where a particularly large body of data from randomized trials has accumulated, more thorough and detailed overview analyses are needed. Such detailed reviews are greatly facilitated if a collaborative group of all the trialists is formed. Such groups have sought to collate individual patient data (a very few key items for every patient randomized). A central statistical secretariat then coordinates the process of data collection, checking, and analysis. Analyses are presented to the whole group for discussion and final reports are published in the name of the whole group. Experience from two very large groups that have followed this model, the Antiplatelet Trialists' Collaboration and the Early Breast Cancer Trialists' Collaborative Group, has shown that detailed collaborative overviews have many benefits: the results are particularly clear and therefore have substantial public health impact; the areas of statistical and medical agreement on the evidence can be defined; the areas of uncertainty (and hence future research priorities) are clarified; and the group can disseminate the results particularly widely and rapidly.

Bias↗
PubMed1993

Antiplatelet and anticoagulant therapy.

Antiplatelet therapy is clearly indicated for long-term secondary prevention after transient ischemic attack and ischemic stroke. In stroke-free patients with atrial fibrillation, oral anticoagulants reduce the risk of stroke, and antiplatelet agents may be a lower risk alternative. For the early treatment of the acute phase of ischemic stroke, the role of antiplatelet and anticoagulant therapy is unclear, but is being evaluated in large clinical trials.

Aspirin↗
PubMed1992

Atrial fibrillation and stroke: prevalence in different types of stroke and influence on early and long term prognosis (Oxfordshire community stroke project)

OBJECTIVE: To determine in patients with first ever stroke whether atrial fibrillation influences clinical features, the need to perform computed tomography, and prognosis. DESIGN: Observational cohort study with maximum follow up of 6.5 years. SETTING: Primary care, based on 10 general practices in urban and rural Oxfordshire. SUBJECTS: Consecutive series of 675 patients with first ever stroke registered in the Oxfordshire community stroke project. MAIN OUTCOME MEASURES: Prevalence of atrial fibrillation by type of stroke; effect of atrial fibrillation on case fatality rate and risk of recurrent stroke, vascular death, and death from all causes. RESULTS: Prevalence of atrial fibrillation was 17% (95% confidence interval 14% to 20%) for all stroke types (115/675), 18% (15% to 21%) for cerebral infarction (97/545), 11% (4% to 11%) for primary intercerebral haemorrhage (7/66), and 0% (0 to 11%) for subarachnoid haemorrhage (0/33). For patients with cerebral infarction the 30 day case fatality rate was significantly higher with atrial fibrillation (23%) than with sinus rhythm (8%); the risk of early recurrent stroke (within 30 days) was 1% with atrial fibrillation and 4% with sinus rhythm. In patients who survived at least 30 days the average annual risk of recurrent stroke was 8.2% (5.9% to 10.9%) with sinus rhythm and 11% (6.0% to 17.3%) with atrial fibrillation. CONCLUSIONS: After a first stroke atrial fibrillation was not associated with a definite excess risk of recurrent stroke, either within 30 days or within the first few years. Survivors with and without atrial fibrillation had a clinically important absolute risk of further serious vascular events.

Aged↗
PubMed1992

Diurnal variation in incidence of stroke: Oxfordshire community stroke project.

OBJECTIVE: To determine whether diurnal variation occurs in the onset of stroke. DESIGN: Community based study over four years. SETTING: Oxfordshire, United Kingdom. SUBJECTS: 105,000 people, of whom 675 had a first ever stroke. 545 had a cerebral infarction, 66 had primary intracerebral haemorrhage, 33 had subarachnoid haemorrhage, and in 31 the type of stroke was not known. MAIN OUTCOME MEASURES: Time of stroke and degree of activity at onset. RESULTS: In the 578 patients for whom it was known whether onset occurred while asleep or awake, the proportion with onset during sleep was 25% (135/545) for cerebral infarction, 17% (11/66) for primary intracerebral haemorrhage, and 0% (0/33) for subarachnoid haemorrhage. This difference persisted if patients in whom it was not known whether they were asleep or awake at onset were classed as asleep. For all stroke types together there was a significant (chi 2 = 218.7, p less than 0.001) diurnal variation with a morning peak between 0800 and 1000, which persisted even after allowing for strokes first noted on waking by redistributing the hour of onset through the preceding eight hours (chi 2 = 47, p less than 0.001). A significant diurnal variation was also found in the onset of cerebral infarction (peak 0800-1000, chi 2 = 208.4, p less than 0.001). Fewer patients had other forms of stroke and the diurnal variations for primary intracerebral haemorrhage (peak 1000-1200) and subarachnoid haemorrhage (peaks 0800-1000 and 1800-2000) were not significant. There seemed to be a second smaller peak for all types of stroke. CONCLUSIONS: All types of stroke are most likely to occur after waking in the morning. The cause of the circadian variation requires further study.

Cerebral Hemorrhage↗
PubMed1991

Classification and natural history of clinically identifiable subtypes of cerebral infarction.

We describe the incidence and natural history of four clinically identifiable subgroups of cerebral infarction in a community-based study of 675 patients with first-ever stroke. Of 543 patients with a cerebral infarct, 92 (17%) had large anterior circulation infarcts with both cortical and subcortical involvement (total anterior circulation infarcts, TACI); 185 (34%) had more restricted and predominantly cortical infarcts (partial anterior circulation infarcts, PACI); 129 (24%) had infarcts clearly associated with the vertebrobasilar arterial territory (posterior circulation infarcts, POCI); and 137 (25%) had infarcts confined to the territory of the deep perforating arteries (lacunar infarcts, LACI). There were striking differences in natural history between the groups. The TACI group had a negligible chance of good functional outcome and mortality was high. More than twice as many deaths were due to the complications of immobility than to direct neurological sequelae of the infarct. Patients in the PACI group were much more likely to have an early recurrent stroke than were patients in other groups. Those in the POCI group were at greater risk of a recurrent stroke later in the first year after the index event but had the best chance of a good functional outcome. Despite the small anatomical size of the infarcts in the LACI group, many patients remained substantially handicapped. The findings have important implications for the planning of stroke treatment trials and suggest that various therapies could be directed specifically at the subgroups.

Age Factors↗
PubMed1991

Recent developments in the diagnosis and management of patients with transient ischaemic attacks and minor ischaemic strokes.

Appropriate management of the patient with transient focal neurological symptoms must start with accurate clinical diagnosis. Wider use of clear diagnostic criteria and symptom checklists, and better knowledge of the clinical features of the 'funny turns' which are not related to transient focal cerebral ischaemia could reduce the present variability in clinical diagnosis of transient ischaemic attacks. More accurate clinical diagnosis contributes to better selection of the most appropriate investigation strategy for each patient. A basic minimum standard of investigation is outlined and perhaps provides a suitable template for audit. Patients with transient ischaemic attacks which are definitely in the carotid distribution may be eligible for entry in trials of carotid endarterectomy. Prudent use of duplex ultrasound studies of the carotid arteries in patients with appropriate symptoms is an effective way to reduce the costs of investigations and their complications (i.e. the number of strokes associated with cerebral angiography). Digital venous subtraction angiography has, by comparison, many disadvantages as a screening tool. Advances in management include: recent statistical overviews which have emphasized the need to consider blood pressure and plasma cholesterol reduction in a large proportion of patients, and the value of long term anti-platelet therapy in reducing the risks of stroke, myocardial infarction and vascular death in both males and females. The value of anticoagulants in patients with atrial fibrillation and transient ischaemic attacks or minor stroke is being tested in current trials.

Cerebral Angiography↗
PubMed1990

Computed tomography in patients with transient ischaemic attacks: when is a transient ischaemic attack not a transient ischaemic attack but a stroke?

In a prospective community-based study, 184 patients with transient ischaemic attacks (TIAs) were identified from a study population of about 105,000 between 1981 and 1986. Computed tomography (CT) was attempted in all those with cerebral ischaemic attacks (n = 152, 83%); patients with amaurosis fugax only (n = 32, 27%) were not scanned routinely. Scans were obtained in 120 (79%) of those with cerebral attacks and 12 (38%) of those with amaurosis fugax. The scans were reported by a neuroradiologist who was blinded to the patients' clinical features. Of 120 (27%:95% confidence interval 19-35) scans in patients with cerebral attacks, 32 showed a focal area of hypodensity or cortical loss, but in only 14 (12%:95% confidence interval 6-18) was this in an area of the brain appropriate to the patients' symptoms. There were no significant differences in the clinical features, the duration of attacks or the prognosis (i.e., risk of death, stroke or myocardial infarction) of patients with and without ischaemic lesions on CT. It is concluded that patients with clinically definite TIAs who have a presumed ischaemic and appropriately sited lesion on CT should not be re-classified as having had a stroke.

Aged↗
PubMed1990

Mood disorders in long-term survivors of stroke: associations with brain lesion location and volume.

Sixty surviving patients from a community-based stroke register who had CT scan evidence of a single brain lesion and neurological signs appropriate to it were interviewed three to five years following their first-ever stroke. Mood disorder (anxiety and depression), physical disability, and intellectual impairment were assessed using standardized measures. The position and volume of the brain lesion was determined from CT scans performed soon after the stroke. The prevalence of depressive disorder was lower in this sample than that reported in previous studies (DSM-IIIR major depression 8.3%; all DSM-IIIR depressive disorders 18.3%). Reports by other workers for an association of depressive disorder either with left-sided brain lesions, or with anteriorly placed lesions in the left cerebral hemisphere, were not supported. Neither was there evidence of a correlation between symptom score and proximity of the lesion to the anterior pole of the left cerebral hemisphere. Psychiatric symptom scores were however greater with larger volume brain lesions. Anxiety disorders, especially agoraphobia, were relatively common (20% if diagnosed in the presence of depressive disorder), but were not related to lesion location or volume.

Activities of Daily Living↗