Stroke; a journal of cerebral circulation
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In selected patients with cerebrovascular insufficiency, an extracranial-intracranial bypass is indicated to increase cerebral blood flow. To assess the effect of this operation upon routine non-invasive testing, 15 patients had oculoplethysmography, carotid phonoangiography and Doppler testing. None of those with a preoperative abnormality were changed after surgery, despite angiographically proven anastomotic patency. Whereas non-invasive tests may correctly identify severe internal carotid stenosis, use of these modalities in their routine form does not predict extracranial-intracranial bypass patency.
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The retinal arterial diameter and its response to changes in perfusion pressure were measured by means of a fundus camera in 65 normal subjects. A reduction of effective MABP was induced by a postural change from a recumbent to an erect position. ⋯ No significant correlations were observed between the retinal arterial reactivity, magnitude of the retinal arterial diameter (range: 60-140 mu), and systemic blood pressure (range of MABP: 75-110 mmHg). These results indicate that the retinal artery has an autoregulatory mechanism which is influenced by aging.
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A population-based stroke incidence study was carried out in Melbourne, Australia, between March 1978 and September 1979. Age-sex specific incidence rates were calculated and shown to be similar to those reported from the United States. At 18 months after the onset of stroke 55% of patients were alive and the probability of survival was shown to be related to the level of consciousness at time of maximum impairment. Seasonal variability of stroke incidence was demonstrated, as was an association between incidence rates and country of birth.