Relationships between perfusion pressure and regional cerebral blood flow in patients with intracranial mass lesions.
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Biomedical subjects
Publications and source records attributed to G Boysen.
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As an offshoot of a larger prospective cardiovascular population study, the present study aimed to determine the 12 months frequency of focal cerebral transient ischemic attacks (TIAs) in persons randomly selected after age stratification from the Copenhagen city population register. A questionnaire of 5 questions pertaining to cerebrovascular attacks sustained within the last 12 months was distributed to 2,357 persons. The TIA-questionnaire was returned by 88%, of whom 22% responded affirmatively to one or more questions. The positive responders were interviewed by phone, and when suspected of having TIAs they were examined by a neurologist. A total of 11 persons proved to have had TIAs, which for the age group of 60 years and over gives o 12 months frequency of 8/1000. Dizziness, ophthalmologic problems and migraine were the most frequent causes of a "false" positive response.
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Platelet aggregation and bleeding time was measured in 43 cerebrovascular patients participating in a controlled double-blind study of low-dose acetylsalicylic acid. In 19 patients with satisfactory inhibition of the platelet aggregation obtained by 50 to 70 mg acetylsalicylic acid per day the bleeding time averaged 11.2 minutes in contrast to 7.0 minutes in the placebo group, p less than 0.001. This study confirms our previous findings of platelet inhibition by low-dose acetylsalicylic acid in patients with cerebrovascular disease. The prolongation of the bleeding time demonstrates that we are dealing not merely with an in vitro phenomenon but with a significant in vivo effect. The study provides the rationale for clinical evaluations of low-dose acetylsalicylic acid in stroke prophylaxis.
The long-term clinical and CT-outcome of 53 conservatively treated patients with spontaneous intracerebral hematomas (ICH) was studied in relation to the acute findings. The acute mortality of ICH was 27%. Determinant for the immediate prognosis was the level of consciousness and the volume of the hematoma. The crucial size was 50 ml with a mortality of 90% for hematomas larger and 10% for hematomas smaller than that. Intraventricular hemorrhage was a bad prognostic sign only in the ganglionic-thalamic hematomas. At follow-up at a median of 4 1/2 years after ICH, 30% of the total series had a completely normal neurological examination and 28% had resumed work. Thirteen per cent had minor neurological deficits and 17% had debilitating sequelae. During the follow-up period 7 patients had died, which indicates an excess mortality for ICH survivors. The CT findings at follow-up consisted of low density areas smaller than the original hematomas, focal atrophy, calcifications and porencephalic cysts. In 10% the CT scan revealed no trace of the previous hematoma.
Cerebral blood flow (CBF) was studied by 133Xenon inhalation tomography in 22 patients with symptoms of ischemic cerebrovascular disease before and after establishment of an extracranial-intracranial bypass shunt. Selection of patients for shunting was based on angiographically demonstrated arterial occlusions and on the finding of focal low flow areas corresponding to the clinical symptoms, that consisted mainly of minor stroke with good remission and with or without subsequent TIAs. It was required that the area of low flow should clearly exceed the CT lesion present in practically all cases. Following surgery, the permanent neurologic deficits remained unchanged, while the TIAs stopped in all but one case. Two patients showed a definite increase of CBF in the low flow area while another two showed a questionable increase. All the other cases, 18 of the 22, showed an unchanged tomographic flow map with no trend towards diminution in extension or severity of the focal hypoperfused area. A persistent low flow in areas with no corresponding CT lesion following alleviation of a possible flow impediment is interpreted to represent an incomplete infarction or diaschisis.
Atrial fibrillation (AF) is associated with an increased risk of stroke. In AF patients with acute stroke, cerebral computed tomography (CT) often reveals old asymptomatic infarcts. To investigate the frequency of such lesions, 29 AF patients and 29 controls in sinus rhythm without history of cerebrovascular disease were CT scanned. Fourteen patients with AF (48%) had abnormal CT scans with areas of low density with sharp demarcation from surrounding tissue compared with 8 patients in sinus rhythm (28%) (p greater than 0.10). However, the number of abnormal areas with apparent tissue loss was significantly higher in the AF group (39 lesions) compared with the control group (16 lesions) (p = 0.033). The lesions were mainly located in the cortex with no significant difference in lesion size between AF patients and controls. The abnormal areas probably reflected small, clinically silent infarcts. We conclude that these lesions are present in AF patients without history of cerebrovascular events and occur more frequently than in controls without atrial fibrillation.
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