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Biomedical subjects

P A Sandercock

Publications and source records attributed to P A Sandercock.

At least 19 recordsLinked to original sources
PubMed2001

Surgery for cervical radiculomyelopathy.

BACKGROUND: Cervical spondylosis causes pain and disability by compressing the spinal cord or roots. Surgery to relieve the compression may reduce the pain and disability, but is associated with a small but definite risk. We sought to assess the balance of risk and benefit from surgery. OBJECTIVES: To determine whether: 1) surgical treatment of cervical radiculopathy or myelopathy is associated with improved outcome, compared with conservative management and 2) timing of surgery (immediate or delayed upon persistence/progression of relevant symptoms and signs) has an impact on outcome. SEARCH STRATEGY: We searched Medline (between 1966 and 1998), Embase (between 1980 and 1998) and the Cochrane Controlled Trials Register. Authors of the identified randomised controlled trials were contacted to detect any additional published or unpublished data. SELECTION CRITERIA: All unconfounded truly or quasi-randomised controlled trials allocating patients with cervical radiculopathy or myelopathy to 1) "best medical management" or "decompressive surgery (with or without some form of fusion) plus best medical management" 2) "early decompressive surgery" or "delayed decompressive surgery". DATA COLLECTION AND ANALYSIS: Two reviewers independently selected trials for inclusion, assessed trial quality and extracted the data. MAIN RESULTS: Two trials involving a total of 130 patients were included. One trial with 81 patients compared surgical decompression with either physiotherapy or cervical collar immobilization in patients with cervical radiculopathy. The short-term effects of surgery, in terms of pain, weakness or sensory loss were superior, however, at one year no significant differences between groups were present. One trial with 49 patients compared the effects of surgery with those of conservative treatment in patients with mild functional deficit associated with cervical myelopathy. No significant differences were observed between groups, up to two years following treatment.

Cervical Vertebrae↗
PubMed2001

Imaging appearance of the symptomatic perforating artery in patients with lacunar infarction: occlusion or other vascular pathology?

Lacunar infarction is associated with distinct clinical features. It is thought to result from occlusion of a deep perforating artery in the basal ganglia, centrum semiovale, or brain stem. However, occluded perforating arteries have only rarely been observed at postmortem in patients with lacunar stroke and have not been noted previously on imaging despite the increasing sophistication of the techniques. We observed nine patients with lacunar stroke imaged with computed tomography and magnetic resonance imaging in whom we observed a linear structure with density or signal features consistent with an occluded (or at least abnormal) perforating artery associated with the relevant lacunar infarct. The appearance might also have been caused by a leak of blood and fluid into the perivascular space around the artery, as in several patients the width of the tubular vessel-like structure (>1 mm in diameter) was greater than the expected width of a perforating artery (<0.8 mm in diameter). This interpretation is supported by the fact that the area of infarction was usually around the abnormal vessel, not at the end of it. We describe the patients' clinical and imaging features, and discuss alternative explanations for the imaging appearance and the implications for gaining insights into the cause of lacunar infarction.

Aged↗
PubMed2001

Variations between countries in outcome after stroke in the International Stroke Trial (IST).

BACKGROUND AND PURPOSE: This study describes the large variations in outcome after stroke between countries that participated in the International Stroke Trial and seeks to define whether they could be explained by variations in case mix or by other factors. METHODS: We analyzed data from the 15 116 patients recruited in Argentina, Australia, Italy, the Netherlands, Norway, Poland, Sweden, Switzerland, and the United Kingdom: We compared crude case fatality and the proportion of patients dead or dependent at 6 months; we used logistic regression to adjust for age, sex, atrial fibrillation, systolic blood pressure, level of consciousness, and number of neurological deficits. We used the frequency of prerandomization head CT scan and prescription of aspirin at discharge to indicate quality of care. RESULTS: The differences in outcome (all treatment groups combined) between the "best" and "worst" countries were very large for death (171 cases per 1000 patients) and for death or dependency (375 cases per 1000 patients). The differences were somewhat smaller after adjustment for case mix (160 and 311 cases per 1000 patients, respectively). Process of care may have accounted for some but not all of the residual variation in outcome. CONCLUSIONS: Adjustment for case mix explained only some of the variation in outcome between countries. The residual differences in outcome were too large to be explained by variations in care and most likely reflect differences in unmeasured baseline factors. These findings demonstrate the need to achieve balance of treatment and control within each country in multinational randomized controlled stroke trials and the need for caution in the interpretation of nonrandomized comparisons of outcome after stroke between countries.

Aged↗
PubMed2001

Risk of early death and recurrent stroke and effect of heparin in 3169 patients with acute ischemic stroke and atrial fibrillation in the International Stroke Trial.

BACKGROUND AND PURPOSE: We sought to investigate the apparently high risk of early death after an ischemic stroke among patients with atrial fibrillation (AF), identify the main factors associated with early death, and assess the effect of treatment with different doses of subcutaneous unfractionated heparin (UFH) given within 48 hours. METHODS: We studied the occurrence of major clinical events within 14 days among 18 451 patients from the International Stroke Trial, first for all treatment groups combined. Then, among patients with AF, we examined the effects of treatment with subcutaneous UFH started within 48 hours and continued until 14 days after stroke onset. RESULTS: A total of 3169 patients (17%) had AF. Seven hundred eighty-four patients were allocated to UFH 12 500 IU SC BID, 773 to UFH 5000 IU SC BID, and 1612 to no heparin. Within each of these groups, half of the patients were randomly assigned to aspirin 300 mg once daily. Compared with patients without AF, patients with AF were more likely to be female (56% versus 45%), to be old (mean age, 78 versus 71 years), to have an infarct on prerandomization CT (57% versus 47%), and to have impaired consciousness (37% versus 20%). The initial ischemic stroke type was more often a large-artery infarct (36% versus 21%). A lacunar stroke syndrome was less common (13% versus 26%). Death within 14 days was more common in patients with AF (17% versus 8%) and more often attributed to neurological damage from the initial stroke (10% versus 4%). The frequency of recurrent ischemic or undefined stroke was not significantly different (3.9% versus 3.3%). The proportion of AF patients with further events within 14 days allocated to UFH 12 500 IU (n=784), UFH 5000 IU (n=773), and to no-heparin (n=1612) groups were as follows: ischemic stroke, 2.3%, 3.4%, 4.9% (P=0.001); hemorrhagic stroke, 2.8%, 1.3%, 0.4% (P<0.0001); and any stroke or death, 18.8%, 19.4% and 20.7% (P=0.3), respectively. No effect of heparin on the proportion of patients dead or dependent at 6 months was apparent. CONCLUSIONS: Acute ischemic stroke patients with AF have a higher risk of early death, which can be explained by older age and larger infarcts but not by a higher risk of early recurrent ischemic stroke, although slightly more patients with AF died from a fatal recurrent stroke of ischemic or unknown type (1.3% versus 0.9%). In patients with AF the absolute risk of early recurrent stroke is low, and there is no net advantage to treatment with heparin. These data do not support the widespread use of intensive heparin regimens in the acute phase of ischemic stroke associated with AF.

Acute Disease↗
PubMed2000

Trials of thrombolysis in acute ischemic stroke: does the choice of primary outcome measure really matter?

BACKGROUND AND PURPOSE: Controversy regarding the risks and benefits of thrombolysis has not been helped by the perception that some trials were "positive" and others "negative" on their primary outcome measure of either "good" or "poor" functional outcome. We wondered whether the definition of good or poor functional outcome might have contributed to this perception, and what effect altering the definition might have on the individual trials and on the systematic review of all the trials combined. METHODS: We analyzed data on functional outcome, extracted from the randomized trials of thrombolysis in acute ischemic stroke, according to good (modified Rankin scale scores of 0 to 1 versus 2 to 6) and poor (modified Rankin 0 to 2 versus 3 to 6) functional outcome, to determine the effects of thrombolysis. RESULTS: Twelve trials (4342 patients, treated up to 6 hours after stroke) contributed to this analysis. Overall, there was no difference in the estimate of treatment effect between the 2 definitions (modified Rankin 0 to 2 versus 3 to 6, and 0 to 1 versus 2 to 6 [ORs 0.83 and 0.79, respectively]). However, the apparent "success" of several individual trials did alter. CONCLUSIONS: We should not place undue emphasis on the results of individual trials, when a change of a single point on the Rankin scale can make the difference between "success" and "failure." Overall, by either analysis, there was a significant benefit in patients treated with thrombolysis up to 6 hours after stroke.

Acute Disease↗
PubMed1999

Can stroke physicians and neuroradiologists identify signs of early cerebral infarction on CT?

Doctors managing acute stroke are expected to recognise signs of early infarction on CT before choosing thrombolytic treatment, according to recent trials and guidelines. The ability of 13 physicians and two neuroradiologists to recognise early infarct signs and decide whether patients should be randomised in a hypothetical stroke treatment trial was tested. Only 65% of the CT scans from 14 stroke patients were correctly identified as normal or abnormal (95% CI 60-69%). Neither observer experience nor knowledge of symptoms significantly improved recognition of abnormality, although experience did significantly improve the observers' ability to reproduce their results. Parenchymal hypodensity was the least well recognised sign. Only 45% (95% CI 40%-50%) of patients were identified correctly for the hypothetical acute stroke treatment trial. Early infarction on CT is not well recognised even by experienced doctors. Part of the problem may be in understanding the definitions of the extent of infarction. These difficulties should be considered in the design of acute stroke treatment trials and in the introduction of any new acute stroke treatments.

Cerebral Infarction↗
PubMed1999

Why do Italian stroke patients receive CT scans earlier than UK patients? International Stroke Trial Collaborators in Italy and the UK.

Computed tomography (CT) scanning is important prior to acute stroke treatment. We wished to identify factors associated with being able to obtain a CT scan quickly, from a recent large stroke treatment trial. A questionnaire survey on the organisation of CT scanning services for stroke was sent to 179 UK and Italian hospitals who had randomised patients into the International Stroke Trial and performed at least one pre-randomisation CT scan. Data from the questionnaire were analysed in conjunction with other patient data. Italian doctors expected the CT scans to be done more quickly than UK doctors, their hospitals were more likely to have a CT scanner operating all the time, and a porter was used less frequently to take the patient to the CT scanner. A few simple changes in the way CT scanning is organised for stroke patients in the UK could speed access to CT considerably.

Cerebrovascular Disorders↗
PubMed1999

Recently occluded intracranial and extracranial carotid arteries. Relevance of the unstable atherosclerotic plaque.

BACKGROUND AND PURPOSE: It is now widely accepted that thrombotic coronary artery occlusion usually follows rupture of an unstable atherosclerotic plaque. The significance of such instability in arteries supplying the brain is less well appreciated. We therefore describe the clinical and pathological features of recent, symptomatic internal carotid artery occlusion to examine the pathogenetic role of plaque instability at both extracranial and intracranial sites. METHODS: Cases were selected from a consecutive series of 188 adult neuropathology autopsies. In 90 of these, the principal neuropathological abnormality was cerebral infarction, in 14 cases due to recent occlusion of 1 or more segments of the internal carotid artery. In each case, a full systemic, cardiovascular, and neuropathological autopsy was performed. Plaque instability was assessed by the presence or absence of a large, necrotic, lipid core; a thin, fibrous cap; and superficial inflammation. RESULTS: Of the 14 cases, 3 showed extracranial (carotid sinus), 7 intracranial, and 4 both extracranial and intracranial carotid artery occlusion. In 6 of the 7 occluded carotid sinuses, thrombus overlay an ulcerated, unstable, atherosclerotic plaque. In 1 extracranial and all 11 intracranial occlusions, there was either no atheroma or a mildly stenotic, stable, fibrous plaque, and in these cases, the cause of occlusion was embolism (8 cases), giant-cell arteritis (1 case), and unknown (3 cases). CONCLUSIONS: Coronary-type rupture of an unstable atherosclerotic plaque is the usual cause of fatal occlusion of the carotid sinus, but other causes usually underlie intracranial carotid occlusion. The nature and consequences of intracranial atherosclerosis require further study.

Adult↗
PubMed1999

Aspirin and heparin in acute ischaemic stroke in older patients.

Over four-fifths of all strokes are due to thrombotic or embolic occlusion of cerebral arteries. There is a strong rationale for considering antithrombotic therapy for the treatment of patients with acute ischaemic stroke. Antiplatelet therapy with 150 to 300 mg of aspirin (acetylsalicylic acid) started within the first 48 hours of an ischaemic stroke improves patient outcome in the short and long term, with a low risk of adverse effects. Anticoagulants such as heparin may reduce the risk of developing deep venous thrombosis and pulmonary embolism in patients with stroke, but randomised controlled trials have demonstrated a significant and dose-dependent risk of intracranial haemorrhage. The routine use of parenteral anticoagulants, including unfractionated heparin, low-molecular-weight heparins and heparinoids in the acute phase of ischaemic stroke is not associated with any net short or long term benefit. Aspirin is, therefore, the antithrombotic drug of choice in the treatment of acute ischaemic stroke.

Acute Disease↗
PubMed1996

Observer variation in the interpretation of intra-arterial angiograms and the risk of inappropriate decisions about carotid endarterectomy.

OBJECTIVE: To determine how often observer variation in the interpretation of intra-arterial angiograms might alter the decision whether or not to refer patients for carotid surgery. METHODS: A prospective study was carried out in a consecutive series of 99 patients with transient ischaemic attacks and minor strokes. Interpretable angiographic films were available for 179 carotid artery bifurcations. Stenosis of the internal carotid artery was measured using mm scales, independently by three different radiologists (A, B, and C), using the European Carotid Surgery Trial method. RESULTS: An analysis of the grouped data showed good to moderate agreement by kappa statistics for radiologists A v B, B v C, and A v C of 0.68, 0.60, and 0.70 respectively. The mean absolute difference in the estimate of stenosis by each of the different radiologists (interobserver variation) was 9.5% and for each radiologist on two separate occasions (intraobserver variation) 8.4%. The degree of observer error was smallest among severely stenosed arteries. Although the absolute differences were small, "clinically important" differences which could change the treatment recommended from surgery to no surgery (or vice versa) occurred between radiologists A and B, B and C, and A and C in: seven (3.9%), six (3.4%), and 11 (6.1%) vessels respectively. CONCLUSIONS: Because observer variation affects all of the imaging methods (Doppler, duplex, contrast arteriography, and MR angiography) used to select patients with transient ischaemic attack and stroke, these findings are likely to be widely relevant. Any centre assessing patients with cerebrovascular disease will need to implement strict quality control measures in the interpretation of angiograms (and other vascular imaging procedures) to minimise observer error and thereby reduce the number of inappropriate decisions made to refer for carotid artery surgery or not.

Carotid Artery Diseases↗
PubMed1996

Considerations in the design of clinical trials of neuroprotective therapy in acute stroke.

Any therapeutic trial of a new treatment for stroke must provide sufficient reliable evidence to convince clinicians and healthcare purchasers of its merits. Clinicians are most likely to be convinced by large independent studies that provide clear evidence of benefit. If the trial is really to alter healthcare delivery, it should also confirm that the treatment is cost-effective enough to satisfy the increasingly critical demands of the healthcare purchasers. Although some of the current trials will be able to detect large benefits, reliable detection of the moderate benefits that seem more plausible with neuroprotection will need to wait until completion of trials that are perhaps an order of magnitude larger. If tens of thousands of patients are to be recruited into trials of neuroprotective therapy, it is essential that the trials have simple practicable designs that allow participation not only by interested university hospitals but also busy general hospitals with few research resources.

Acute Disease↗
PubMed1995

Hospital services for patients with acute stroke in the United Kingdom: the Stroke Association Survey of consultant opinion.

A national postal survey of all UK hospital consultant geriatricians, general physicians and neurologists was performed in 1992/3 in order to describe the provision of hospital stroke services in the United Kingdom and to assess whether the recommendations of the King's Fund consensus conference on stroke had been widely implemented. Of 3478 survey forms, 2923 (84%) were returned and, of these 1953 (67%) consultants indicated that they routinely cared for patients with acute stroke. On their stated estimates, the survey respondents had admitted approximately 107,000 patients with acute stroke in the previous year, 40% of whom were cared for by geriatricians. Sixty-three per cent (1239/1953) worked in District General Hospitals. Few (5%) had access to an acute stroke unit, and a majority (51%) of consultants were uncertain of the benefits of such units. Less than half (44%) had access to a specialized stroke rehabilitation unit, but a majority (68%) were certain of the benefits of stroke rehabilitation units. Although a majority of consultants had on-site CT scanning, about a third of all UK stroke patients were admitted to a hospital without on-site CT facilities. Most (90%) consultants would want a CT scan themselves if they had a stroke. Only about a third of consultants were aware of a recent audit of stroke care in their hospital, or had a hospital policy for the implementation of minimum standards of stroke care, and less than half routinely provided written information for patients or carers. This survey illustrated that five years after the publication of the King's Fund consensus statement on the treatment of patients with acute stroke UK hospital stroke services are still poorly organized. Access to CT scanning for stroke patients is improving, but is still insufficient.

Acute Disease↗
PubMed1994

Prevalence of impaired cerebrovascular reserve in patients with symptomatic carotid artery disease.

Cerebrovascular reserve (CVR) was studied in 104 consecutive patients with symptomatic carotid territory disease and ipsilateral internal carotid artery stenosis. Overall, 30 of 104 patients (29 per cent) had impaired CVR. The frequency of CVR impairment increased with the severity of internal carotid artery stenosis: impairment was present in none of 11 patients with stenosis of less than 50 per cent, four of 24 with stenosis of 50-69 per cent, 14 of 41 with stenosis of 70-89 per cent and 12 of 28 with stenosis of 90-99 per cent. Patients presenting with a stroke were significantly more likely to have impaired CVR than those with transient ischaemic attacks and/or amaurosis fugax (odds ratio 3.7 (95 per cent confidence interval (c.i.) 1.5-9.0)), as were those with a residual neurological deficit (odds ratio 4.3 (95 per cent c.i. 1.6-11.5)) and evidence of infarction from computed tomography (odds ratio 3.8 (95 per cent c.i. 1.6-9.4)).

Adult↗