PubMed Health⌕ Search

Biomedical subjects

J Wardlaw

Publications and source records attributed to J Wardlaw.

26 records · Page 2Linked to original sources
PubMed1997

The drug trials that have influenced our clinical practice in acute ischaemic stroke.

With the possible exception of aspirin, there are still no drug treatments which have been found to be so effective in randomised controlled trials, and meta-analyses of such trials, that they should be used routinely in acute ischaemic stroke. The evidence on thrombolysis is tantalising but with only about 3500 randomised patients in all the trials put together it is too early to say how, and for whom, this promising treatment should be used, particularly bearing in mind the risk of intracranial haemorrhage; the evidence so far is enough to persuade us to enter our patients into further large trials of thrombolysis but it is not enough to justify this treatment in our routine clinical practice.

Fibrinolytic Agents↗
PubMed1996

Reproducibility of metabolite peak areas in 1H MRS of brain.

We studied the reproducibility of metabolite signals (from N-acetyl aspartate [NAA], choline, and creatine) measured with a standard single-voxel proton magnetic resonance spectroscopy technique (PRESS, TE = 135 ms, 8 ml VOI) in vitro and in two groups of normal volunteers. Spectral peak areas were quantified both by integration and by curve-fitting. In the in vitro study, the "between-days" variability (coefficient of variation [CV]) of measurements ranged from 0.9% to 2.3%. In the first group of volunteers (n = 12), single voxel spectroscopic measurements (8 ml VOI, 256 acquisitions [ACQs]) were made from mirror-image parts of the right and left hemispheres on 2 separate days. The "between-days" CV of measurements ranged from 9% to 18% for metabolite areas, and from 10% to 26% for metabolite area ratios. There were no significant differences between quantification method or hemisphere. After checking and optimising the MR scanner performance (in fact, it was virtually optimal), the second group (n = 4) each had six sequential single voxel spectroscopic measurements (each of 64 ACQs) from the right hemisphere (without moving the voxel) on each of 4 separate days. Even when the metabolites were measured from the same place in the same hemisphere sequentially six times in a 20-min period, the "within-run" CVs ranged from 4.4% to 17.2% for metabolite areas and from 9.7% to 17.0% for metabolite area ratios. The between-days CVs for the subjects ranged from 7.7% to 25.8% (metabolite areas) and from 10.1% to 22.6% (metabolite area ratios). The variability is due to a combination of random noise, subject motion, baseline artefacts in the spectra, and uncertainties in repositioning the VOIs. It is likely to represent the best reproducibility possible with 8-ml VOIs in cooperative, healthy volunteers carefully positioned on each occasion in a standard clinical scanner. Changes in metabolite levels in individuals must therefore be of the order of 20-40% before we can be reasonably confident of measuring them. Reproducibility in patients, who may be less cooperative, will probably be no better, and this must be taken into account in the interpretation of MRS studies in patients with brain pathology; for example, stroke, head injury, and tumours.

Adult↗
PubMedDate not supplied

Thrombo-embolic stroke, moya-moya phenomenon and primary oxalosis.

We present the clinical, radiological and autopsy findings in a 32-year-old woman with primary oxalosis, who suffered recurrent bilateral carotid territory infarcts. The overall features were those of moya-moya syndrome, with bilateral, ultimately thrombotic, occlusion of the distal internal carotid arteries. Vessel pathology suggests an underlying intimal vasculopathy, the possible relation of which to the patient's metabolic abnormality is discussed.

Adult↗
PubMedDate not supplied

Families of trials: the answers to all our questions?

Many of the important clinical decisions we make on a daily basis in stroke medicine are not supported by adequate evidence. This leads to variations in practice. If practice influences outcome, this must be regarded as unacceptable since it implies that many patients are receiving sub-optimal treatment. Where the advantages of certain treatment policies over others are only moderate, large randomised clinical trials provide the most reliable evidence of effectiveness. However, only a tiny proportion of patients with stroke are randomised in trials. Instead, the majority are exposed to treatments allocated haphazardly, rather than randomly, which serves only to delay the emergence of evidence concerning the relative merits of alternative treatment approaches. We suggest that we might increase the proportion of patients who contribute to advancing our knowledge by developing 'families' of trials. A 'family' would comprise a series of randomised trials into which patients with stroke may be enrolled either simultaneously or sequentially into one or more of the trials which would share common systems for randomisation and follow-up. Such a system would facilitate large, simple, randomised trials, reduce research costs, increase the generalisability of trial results and allow clinicians and patients to contribute to advancing our knowledge whenever they are uncertain about the best treatment. In this article, we discuss the advantages of this approach, some of the problems and their potential solutions.

Bias↗
PubMedDate not supplied

Antiplatelet, anticoagulant and fibrinolytic agents in acute ischaemic stroke and TIA.

In acute ischaemic stroke and transient ischaemic attacks both platelets and coagulation factors are activated. This is the rationale for the use of antiplatelet and anticoagulant agents in the prevention of acute ischaemic stroke. Evidence also suggests that antiplatelet agents anticoagulants and dissolution of a thrombus occluding a major cerebral vessel (by means of fibrinolytic agents) may be beneficial as therapy for the acute phase of ischaemic stroke.

Anticoagulants↗