ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

This report summarizes the study design and organization of a multicenter, randomized trial of carotid endarterectomy for the treatment of asymptomatic carotid stenosis. The Asymptomatic Carotid Atherosclerosis Study will determine whether the addition of carotid endarterectomy to aspirin plus risk factor modifications affects the incidence of ipsilateral transient ischemic attack, amaurosis fugax, and retinal and cerebral infarction in patients with asymptomatic hemodynamically significant carotid stenosis in at least one artery. Power calculations are based on assumptions of α = 0.05 (two-sided test) with annual event rate 3% transient ischemic attack and 1% cerebral infarction per year. The study has 90% power for detection of a 25% difference in events in a 5-year study. Two continuous validation programs are in use: a Doppler/angiogram correlation study for each Doppler instrument used in screening potential candidates and a transient ischemic attack/stroke questionnaire/validation study for verification of end points. Quality assurance is a major component in study design.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

It is common to find computed tomography scan evidence of prior stroke without a history of such an event. The frequency, risk factors for, and relevance of silent strokes are unknown. The Framingham cohort of 5,184 men and women aged 30–62 years and free of stroke at entry to the study have been followed with periodic examinations since 1950. We studied the silent strokes found on computed tomography scan of all initial strokes that occurred between January 1, 1979, and July 31, 1987. During these 8V2years, 164 initial strokes occurred; 124 had computed tomography scans performed. There were 13 (10%) with silent stroke, 71 had abnormalities related to their presenting acute stroke, and 40 had normal computed tomography scans. There were 15 silent lesions; eight were lacunar infarcts in the basal ganglia-internal capsule area, seven were small cortical infarcts. Glucose intolerance was the sole risk factor that occurred significantly more frequently (11 of 13) in the group with silent lesions (p< 0.04) than in the group with computed tomography evidence of acute stroke. Silent stroke is not rare; it was present in at least 10% of acute initial stroke patients arising in a general population. The relation of these silent lesions to the development of “vascular” dementia and poststroke disability deserves further study.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The SEPIVAC study (Italian initials for “epidemiologic study of incidence of acute cerebrovascular disease”) is a community-based epidemiologic survey of incidence and outcome of cerebrovascular disease in the territory of the 6th Local Health Unit, Umbria, Italy, where 49,101 people live. All cases were registered with the study either by notification from general practitioners or by check of hospital admission within the study area and in the two hospitals of Perugia. Death certificates were looked at as well. Patients were registered with the study when the clinical picture fulfilled the definition of stroke and transient ischemic attack (TLA) adopted for this study. Patients were followed up at approximately 30 days and 6 months. During the Arst year of the study (September 1, 1986 to August 31, 1987), 189 cases were registered: 108 suffered a “first ever in a lifetime” stroke, 30 a recurrent stroke, and 51 a “first ever in a lifetime” transient ischemic attack. Sixty-one percent of patients (71% of first strokes) had a computed tomography scan. For our study, the crude annual incidence rate of first stroke was 2.2 per 1,000 (confidence intervals 1.81–2.66); the standardized rate to the European population was 1.36 (confidence intervals 1.06–1.74). At least 83% of first strokes were due to cerebral ischemia; in 26 cases a clinical diagnosis of lacunar ischemia was made. The 30-day case fatality rate was 21%; 25% of our patients had recovered completely or almost completely after 1 month.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We investigated the prevalence of stroke in Taiwan in an epidemiologic study of stroke, diabetes, and cardiovascular disease that used a two-phase survey design. The study population was drawn by cluster sampling and consisted of both urban and rural communities from four regions of Taiwan. There were 8,705 people 36 years of age or older interviewed during the period of October 1 to December 31, 1986, and 143 cases of completed stroke were later identified by a neurologist. The point prevalence rate for people aged 36 or older in our study was 1,642/100,000 population (95% confidence interval 1,389–1,942/100,000). Prevalence rates differed significantly among the four study regions and between urban and rural communities; prevalence was greater in northern Taiwan and in urban communities. Percentages of the major types of stroke in 143 stroke survivors were as follows: cerebral infarction 67.1% (96 cases), cerebral hemorrhage 14.0% (20 cases), subarachnoid hemorrhage 4.2% (six cases), and unclassified 14.7% (21 cases). Of the stroke survivors, 67.1% were independent in activities of daily living, and 75.5% were independent in ambulation. Hypertension, heart disease, diabetes mellitus, and a family history of stroke were significantly more common in stroke survivors than in strokefree individuals.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We designed a 15-item neurologic examination stroke scale for use in acute stroke therapy trials. In a study of 24 stroke patients, interrater reliability for the scale was found to be high (mean K = 0.69), and test-retest reliability was also high (mean K = 0.66–0.77). Test-retest reliability did not differ significantly among a neurologist, a neurology house officer, a neurology nurse, or an emergency department nurse. The stroke scale validity was assessed by comparing the scale scores obtained prospectively on 65 acute stroke patients to the patients' infarction size as measured by computed tomography scan at 1 week and to the patients' clinical outcome as determined at 3 months. These correlations (scale-lesion sizer= 0.68, scale-outcomer= 0.79) suggested acceptable examination and scale validity. Of the 15 test items, the most interrater reliable item (pupillary response) had low validity. Less reliable items such as upper or lower extremity motor function were more valid. We discuss methods for improving the reliability and validity of brief examination scales to be used in stroke therapy trials.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

As part of a prospective therapy study of 65 patients with acute, nonhemorrhagic, cerebral infarction, computed tomographic scans of the head were obtained at admission, 7–10 days, and 3 months. The scans were analyzed for the presence, site, size, and volume measurement of the infarction. At 7–10 days, the mean infarction volume as measured by computed tomography was 55 cm3or about 4 × 4 × 3.5 cm (range = 0–507 cm3). At 3 months, the mean infarction volume decreased by 25% to 41 cm3. For the 26 scans showing infarction at the time of admission, the mean lesion volume was 33 cm3at admission, 51 cm3at 7–10 days, and 49 cm3at 3 months. With lesion size at 7–10 days expressed as percentage of total brain volume, the mean infarction size was only 5%. Of the 49 patients with lesions revealed by computed tomography at 7–10 days, 20 had an infarction of 1% or less of total brain volume, while only six had an infarction of 20% or more of total brain volume. The lesion volumes as measured by the 7–10-day computed tomography correlated with the neurologic examination scores on admission (Spearman's rank-order correlation = 0.78) and with the scores at 1 week (Spearman's rank-order correlation = 0.79).

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We examined the brains of 14 patients (four men and 10 women, mean age 68.9 years) who died from brain herniation after cardioembolic stroke with persistent occlusion of the internal carotid-middle cerebral arterial axis. Our examination showed hemorrhagic infarct in seven patients and pale infarct in the other seven, contradicting the commonly proposed pathophysiologic mechanism for the development of hemorrhagic infarct that the opening of previously occluded vessels makes an infarct hemorrhagic. Analysis of blood pressure after stroke revealed one or more surges of arterial hypertension or rapid rise of blood pressure in patients with hemorrhagic infarct without a reopening of the occluded artery. Such arterial hypertension was not always present in patients with pale infarct. Hemorrhage into an infarct with persisting occlusion of the proximal artery is assumed to occur when the involved blood vessels are exposed to the force of arterial blood pressure from the leptomeningeal collaterals. This occurs when arterial blood pressure rises after stroke in the presence of efficient leptomeningeal collaterals and before occlusion of these collaterals by a swollen cerebral hemisphere containing a large infarct.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We measured cerebral blood flow in 10 consecutive, but selected, patients with acute ischemic stroke (< 48 hours after onset) before and after hemodilution. Cerebral blood flow was measured by xenon-133 inhalation and emission tomography, and only patients with focal hypoperfusion in clinically relevant areas were included. Hemodilution was done according to the hematocrit level: for a hematocrit >42%, 500 ml whole blood was drawn and replaced by the same volume of dextran 40; for a hematocrit between 37% and 42%, only 250 ml whole blood was drawn and replaced by 500 cc of dextran 40. Mean hematocrit was reduced by 16%, from 46±5% (SD) to 39±5% (SD) (p< 0.001). Cerebral blood flow increased in both hemispheres by an average of 20.9% (p< 0.001). Regional cerebral blood flow increased in the ischemic areas in all cases, on an average of 21.4±12.0% (SD) (p< 0.001). In three patients, a significant redistribution of flow in favor of the hypoperfused areas was observed, and in six patients, the fractional cerebral blood flow increase in the hypoperfused areas was of the same magnitude as in the remainder of the brain. In the last patient, cerebral blood flow increased relatively less in the ischemic areas. Our findings show that cerebral blood flow increases in the ischemic areas after hemodilution therapy in stroke patients. The marked regional cerebral blood flow increase seen in some patients could imply an improved oxygen delivery to the ischemic tissue.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Seventeen patients with an intracranial arteriovenous malformation were studied with positron emission tomography. Cerebral blood flow, cerebral blood volume, oxygen extraction fraction, and glucose and oxygen metabolism were evaluated in both hemispheres, excluding the area of the malformation itself. Patients were divided into three groups according to the size of their malformation, and results obtained were compared with studies in healthy volunteers. The glucose metabolism was significantly (p< 0.0l) decreased in the ipsilateral hemisphere in all patients. The cerebral blood volume was significantly increased (/? < 0.001) ipsilaterally in the three groups, and contralaterally in patients with medium- and large-sized arteriovenous malformations. The cerebral blood volume to cerebral blood flow ratio, an index of vascular mean transit time, was significantly increased (p< 0.005) ipsilaterally in patients with mediumand large-sized malformations and contralaterally in patients with large ones. Cerebral blood flow, oxygen extraction fraction, and oxygen metabolism were within the normal range bilaterally in all three groups, but oxygen extraction fraction tended to be higher in patients with larger lesions. The lack of significant change in oxygen metabolism suggests that oxygen metabolism in cortical areas remote from the arteriovenous malformation has been maintained by compensatory hemodynamic mechanisms. These data reveal widespread metabolic and hemodynamic consequences of arteriovenous malformations and suggest that they are associated with impairment of glucose metabolism, both in ipsilateral regions remote from the lesion and in the contralateral hemisphere in patients with large lesions.

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID