ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The pilot study of the Systolic Hypertension in the Elderly Program was a randomized, double‐blind, placebo‐controlled trial of drug therapy for isolated systolic hypertension. It followed 551 elderly participants with untreated blood pressures of >160/< 90 mm Hg for an average of 34 months. Mean age of the participants was 72 years; 63% were women, and 82% were white. Pretreatment blood pressures averaged 172/75 mm Hg. Participants were randomly assigned to treatment with chlorthalidone or placebo as Step I medication. Blood pressures at annual visits averaged 141/68 and 157/73 mm Hg for the drug‐treated and placebo‐treated groups, respectively, with 60% and 33% of the survivors on blinded medication having systolic blood pressures of < 160 nun Hg at their last annual visit. All‐cause mortality rates for the drug‐treated and placebo‐treated groups were 25.4 and 22.7 deaths per 1,000 participant‐years of risk, and rates for definite “first stroke” were 8.3 and 12.8 per 1,000 years of risk. Differences between groups were significant for systolic and diastolic blood pressure but not for death or stroke rates. A full‐scale study has begun to determine the effects of drug therapy for isolated systolic hypertension on stroke and mortality rates. (Stroke1989;20:4–13)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Stroke mortality has been falling rapidly in this country since 1973. To investigate age‐race‐sex effects on stroke mortality, we studied US vital statistics during 1950–1972 and 1973–1981 in 55–64‐, 65–74‐, and 75–84‐year‐old race‐sex groups. The accelerated rate of decline in stroke mortality since 1973 has had a substantial public health impact, with >200,000 fewer stroke deaths than would otherwise have occurred. For all groups, stroke mortality declined at a greater rate (/? < 0.05) in 1973–1981 than during 1950–1972. The rates of decline during 1973‐ 1981 were greater with increasing age (/? < 0.05) and were more substantial for younger blacks. There were no consistent differences in the rate of decline by sex. The greater rate of decline hi absolute stroke mortality in the older age groups and blacks was explained by higher baseline mortality in these groups. Overall, stroke mortality decreased by approximately 2%/yr in 1950‐ 1972 and by approximately 7%/yr after 1973. Rank order of average annual percent decline after 1973 by age‐race‐sex groups did not correspond to rates of change in treatment or control of hypertension obtained from three national surveys. The accelerated rate of decline after 1973 may have resulted from improved antihypertensive therapy, but our findings fail to confirm this hypothesis and suggest that treatment of hypertension may not be the principal reason for the decline in stroke mortality. (Stroke1989;20:14–21)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We reviewed demographic data on patients having 2,256 carotid endarterectomies in eight large hospitals in North Carolina to determine the frequency of blacks among these patients. Blacks comprised only 4.6% of the patients having carotid endarterectomy even though they comprised 26% of all patients discharged and 22% of the general population of the state. Data from the National Inpatient Profile of the Commission on Professional and Hospital Activities, which represents patients discharged from short‐term, nonfederal hospitals throughout the United States, show that nationwide, blacks comprise only 2.7% of the patients having carotid endarterectomy, whereas they comprise 12.0% of all patients discharged, 12.1% of the general population, and 10.7% of patients discharged following Class I surgical procedures. Blacks have only 67 carotid endarterectomies per 100,000 patients discharged; this rate is five or more times higher in whites. Among black patients having carotid endarterectomy, women predominate, whereas men predominate among white patients having carotid endarterectomy (/⩾0.006). The underrepresentation of blacks among patients having carotid endarterectomy lends support to the concept that carotid vascular disease in blacks is distributed intracranially rather than extracranially as opposed to the extracranial rather than intracranial distribution in whites. (Stroke1989;20:22–26)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We evaluated platelet accumulation in carotid arteries by means of a dual‐radiotracer method, using indium‐Ill‐labeled platelets and technetium‐99m‐4abeled human serum albumin, in 123 patients (92 men, 31 women; median age 60 years). Sixty patients had symptoms of transient ischemic carotid artery disease, and 63 patients with peripheral arterial occlusive disease served as controls. Antiplatelet treatment with acetylsalicylic acid was taken by 53 of the 123 patients. In 36 of the 60 symptomatic patients, platelet scintigraphy was repeated 3–4 days after carotid endarterectomy. Comparison of different scintigraphic parameters (platelet accumulation index and percent of the injected dose of labeled platelets at the carotid bifurcation) showed no significant differences between symptomatic and asymptomatic patients, and the severity of stenosis and the presence of plaque ulceration also had no influence on the parameters. There was no difference between patients with a short ( < 4 weeks) or long (>4 weeks) interval from the last transient ischemic attack to scintigraphy and no difference between patients with or without antiplatelet treatment. Classifying the patients according to plaque morphology judged by high‐resolution real‐time ultrasonography also demonstrated no differences. No significant correlation was found between any scintigraphic parameter and other platelet function parameters such as platelet survival time, platelet turnover rate, and concentration of platelet‐specific proteins. Quantification of platelet deposition after carotid endarterectomy in 36 patients demonstrated a significant increase of the median platelet accumulation index and the percent injected dose index. There were no significant differences between patients receiving high‐dose (1.0 g/day) or low‐dose (0.1 g/day) acetylsalicylic acid in scintigraphic results. The presence and amount of scintigraphically detectable platelet deposition after carotid endarterectomy was of no prognostic value concerning the risk of a postoperative neurologic deficit or of developing severe restenosis within the first few months. We conclude that platelet scintigraphy with the dual‐radiotracer method has no value in the clinical investigation of carotid artery disease. (Stroke1989;20:27–33)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

A number of clinical trials suggest that the antithrombotic effect of aspirin is limited to men. To test the possibility that this is due to a sex difference in the inhibitory effect of aspirin on platelet behavior, we studied whole‐blood platelet aggregation in men and women and in male patients with carcinoma of the prostate receiving hormone therapy. The in vitro inhibitory effect of aspirin on so‐called spontaneous platelet aggregation induced by stirring whole blood and monitored by the decrease in the number of singleton platelets was greater in men (mean±SD inhibitory ratio 1.54±0.30 in men, 1.23+0.22 in women;p< 0.001). The inhibitory effect of aspirin was reduced in orchiectomized male patients and was restored by the addition of testosterone to blood samples. Estradiol had no detectable influence on the inhibitory effect of aspirin. Testosterone thus seems to influence platelet aggregation and its inhibition by aspirin as assessed by whole‐blood hi vitro aggregometry. Possible mechanisms for this effect of testosterone and its relevance to the choice of antithrombotic therapy are discussed. (Stroke1989;20:34–37)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We studied platelet function in whole blood, a situation that better reflects the in vivo state, from 85 patients with acute ischemic stroke and from 19 healthy controls. Patients receiving no antithrombotic drugs demonstrated increased platelet dense body secretion without an associated increase in platelet aggregation, thus raising the possibility that dense body secretion may be of separate importance in cerebral infarction. Our results also suggest that dense body secretion may occur independently of aggregation. Heparin and heparin plus warfarin were ineffective in reducing the high level of dense body secretion seen in acute cerebral infarction, whereas treatment with aspirin plus dipyridamole inhibited both dense body secretion and platelet aggregation. It seems worthwhile to investigate the usefulness of antiplatelet drugs in the treatment of acute ischemic stroke wherein clinical outcome is correlated with the extent of suppression of platelet dense body secretion. (Stroke1989;20:38–44)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We studied the response of cerebral blood flow to acute step decreases in arterial blood pressure noninvasively and nonpharmacologically in 10 normal volunteers during normocapnia, hypocapnia, and hypercapnia. The step (approximately 20 mm Hg) was induced by rapidly deflating thigh blood pressure cuffs following a 2‐minute inflation above systolic blood pressure. Instantaneous arterial blood pressure was measured by a new servo‐cuff method, and cerebral blood flow changes were assessed by transcranial Doppler recording of middle cerebral artery blood flow velocity. In hypocapnia, full restoration of blood flow to the pretest level was seen as early as 4.1 seconds after the step decrease in blood pressure, while the response was slower in normocapnia and hypercapnia. The time course of cerebrovascular resistance was calculated from blood pressure and blood flow recordings, and rate of regulation was determined as the normalized change in cerebrovascular resistance per second during 2.5 seconds just after the step decrease in blood pressure. The reference for normalization was the calculated change in cerebrovascular resistance that would have nullified the effects of the step decrease in arterial blood pressure on cerebral blood flow. The rate of regulation was 0.38, 0.20, and 0.11/sec in hypocapnia, normocapnia, and hypercapnia, respectively. There was a highly significant inverse relation between rate of regulation and PacOj (p< 0.001), indicating that the response rate of cerebral autoregulation in awake normal humans is profoundly dependent on vascular tone. (Stroke1989;20:45–52)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Blood flow velocity in the middle cerebral artery, determined by transcranial Doppler ultrasonography, was monitored during 31 carotid endarterectomies. Electroencephalogram (EEG) was also monitored, and regional cerebral blood flow (rCBF) was measured. The relation between rCBF and mean velocity was dependent on the rCBF level; the correlation was strong if rCBF was less than 20 ml/100 g/min but weak if rCBF was greater than that level. Ipsilateral EEG suppression was related to a rCBF threshold of 9 ml/100 g/min and to a mean velocity threshold of 15 cm/sec; the rCBF threshold was more specific for EEG change. Postischemic hyperemia was evident in measurements of mean velocity but not of rCBF. These disparities between mean velocity and rCBF seemed to be due to three factors: 1) disproportionately high mean velocity in patients with stenosis of the middle cerebral artery, 2) a nonlinear relation between mean velocity and rCBF, and 3) the anatomically different regions of the brain in which mean velocity and rCBF are measured. The velocity measurement appeared to be relatively more sensitive than rCBF to hemodynamic events in the corpus striatum and internal capsule. (Stroke1989;20:53–58)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We determined the angiographic presence of extracerebral and intracerebral arterial disease in 122 patients with minor stroke within the carotid territory; we excluded patients with a recognized cardiac source of emboli. Based on clinical features and computed tomographic findings, patients were classified as having lacunar infarcts (n= 61), nonlacunar infarcts (n= 53), and infarcts of indeterminate type (n= 8). Severe carotid bifurcation disease (>50% stenosis or occlusion) was significantly more common in nonlacunar than in lacunar infarcts, on both the ipsilateral (p< 0.001) and the contralateral (p< 0.01) sides; 79% of the patients with nonlacunar infarcts had severe carotid bifurcation and/or middle cerebral artery disease on the ipsilateral side compared with 3.3% of the patients with lacunar infarcts. Our data underscore the need for classification of patients by the underlying mechanisms in future studies of treatment of ischemic stroke. (Stroke1989;20:59–64)

ISSN:0039-2499    

出版商:OVID    

年代:1989

数据来源: OVID