ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundMany pathologic conditions are characterized by a blunted nocturnal decline in blood pressure.ObjectiveTo review the evidence that African Americans display a similar pattern and examine factors associated with the pattern.MethodWe reviewed published racial comparisons of patterns of ambulatory blood pressure in adults and youths.ResultsAuthors of 15 studies reported finding blunted nocturnal declines in African Americans and authors of two studies did not. Authors of studies of Africans in Africa and of 'blacks' from other countries reported normal nocturnal declines. Both intake of sodium and indexes of body size have been related to nocturnal blood pressure in African-American youths. This pattern is related to greater than normal target-organ changes.ConclusionWe conclude that the race of a patient should be considered when evaluating a 24 h pattern of blood pressure in an adolescent; and the blunted nocturnal decline displayed by many African-American adolescents is the result of a gene-environment interaction and therefore is susceptible to modification through changes in diet, level of activity, and other environmental factors.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundThe determination of hypertension in a given population depends on the knowledge of population norms for blood pressure. This is true for both casual blood pressure (CBP) measurements and the newest and most promising technology of ambulatory blood pressure monitoring (ABPM).ObjectiveTo design an ambitious multinational co-operative study to determine normal blood pressure data in Brazilian children.MethodsThe study was designed to determine normative data for CBP, using the Task Force technical recommendations for age-, sex- and height-percentile-specific blood pressure values. The proposed procedure is as follows. ABPM will be studied in a random subgroup of individuals, to develop similar normative data. These data will be correlated to CBP measurements and to echocardiographic findings as a measure of end-organ damage. All patients who are diagnosed by CBP measurement to be hypertensive will also be studied by ABPM, and studies of target-organ damage will be performed. Family and medical histories will be evaluated by questionnaire and first-degree relatives will be evaluated for CBP measurement. Hypertensive patients will form a cohort for long-term follow-up. These data will be the foundation for studies of hypertension in Brazilian children.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo examine the extent to which ambulatory blood pressure was predicted by blood pressure levels exhibited during talking segments of a laboratory protocol and by resting blood pressures in male and female adolescents from three ethnic groups: African, European and Hispanic Americans.DesignThis was a laboratory-field study incorporating an experimental study of reactivity of blood pressure during a laboratory protocol and an observational study of 24 h ambulatory blood pressure (ABP) monitoring.MethodsResting blood pressure, reactivity of blood pressure, 24 h ABP, and activity, height, and maturation of a multi-ethnic sample of 373 male and female adolescents aged 11–16 years were measured. A mixed-effects model for repeated measures was the statistical approach, with systolic and diastolic blood pressures as separate, dependent variables.ResultsPercentiles of ABP by sex, ethnic group, and height are presented. High and mixed blood pressure reactors in the laboratory had higher levels of 24 h ABP and higher levels of blood pressure load during the daytime. African Americans had higher ABP than did European and Hispanic Americans.ConclusionsBlood pressure measured during laboratory tasks that require talking might be useful as a screening device to identify adolescents with high blood pressures. Further study will be necessary in order to quantify the sensitivity of the laboratory protocol as an indicator of high blood pressure compared with casual measurement of blood pressures. If laboratory patterns of blood pressure could be used to predict which individuals have high levels of blood pressure during the course of daily activities, the laboratory protocol would be a useful screening tool, identifying high-risk individuals.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundAmbulatory blood pressure (ABP) monitoring is used increasingly to evaluate the blood pressure of children and adolescents. Reference values based on a sufficiently high number of healthy children are necessary to estimate the limits of the 'normal' range.ObjectiveTo begin to define the normal range of values for pediatric ABP.DesignIn this multicenter trial, we pooled ABP records of 1141 healthy children and adolescents with body heights between 115 and 185 cm. The study was carried out at seven centers, according to a common procedure. Only oscillometric devices (SpaceLab 90207 and Meditech) were included in the evaluation.ResultsThe 50th percentile for 24 h systolic ABP increased moderately with height, from 103mmHg to 113mmHg in girls and from 105mmHg to 120mmHg in boys. The 50th percentile for diastolic 24 h means was 66± 1 mmHg, irrespective of height or sex. Diastolic daytime means were 73±1 mmHg, which is remarkably high compared with reference values for casual blood pressure. The mean nocturnal systolic and diastolic ABP values (0000–0600 h) were 13±6% and 23±9% less than the daytime means (0800–2000 h), respectively.DiscussionThis multicenter study is, to date, the largest descriptive estimation of the normal range of values for pediatric ABP monitoring. Further investigation is needed, to evaluate the influences of genetic and environmental background, and that of the monitoring device, on pediatric ABP measurements. The optimal range for ABP in children as defined by cardiovascular prognosis or end-organ damage remains to be established.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In clinical medicine, blood pressure is usually measured by conventional sphygmomanometry. Although it seems simple at first sight, this procedure is fraught with potential sources of error, which may arise from the subject, the observer, the sphygmomanometer or the overall application of the technique. Automated techniques of blood pressure measurement such as ambulatory monitoring and self-measurement, reduce the limitations of conventional sphygmomanometry. However, the diagnostic thresholds applicable for conventional sphygmomanometry cannot be extrapolated to automated measurements. During the past 10 years criteria for normality have gradually been developed for ambulatory blood pressure (ABP) monitoring of adults. First, the distribution of the ABP in normotensive subjects and untreated hypertensive patients who had initially been recruited and classified on the basis of their conventional blood pressure was studied. Second, authors of various epidemiological studies investigated the distributions of the conventional blood pressure and the ABP in the population at large. Third, authors of several reports attempted to validate the preliminary thresholds for ambulatory monitoring by correlating the ABP to left ventricular hypertrophy, other intermediary signs of target-organ damage or the incidence of cardiovascular morbidity or mortality. Finally, clinical trials should be mounted to prove that it is beneficial to patients as well as cost-effective to diagnose and treat hypertension on the basis of ambulatory monitoring rather than solely under the guidance of conventional sphygmomanometry. For measurements of systolic/diastolic ABP in adults, the proposed upper limits of normotension are 130/80 mmHg for the 24 h blood pressure and 135/85 and 120/70 mmHg for the daytime and night-time blood pressures, respectively; for the self-measured blood pressure 135/85 mmHg might be the upper limit of normality. With regard to ABP monitoring, a large database already supports the proposed diagnostic thresholds in terms of their associations with left ventricular hypertrophy and with the incidence of cardiovascular complications; the evidence to validate the thresholds for the self-recorded blood pressure, to a large extent, must still be collected. In conclusion, the newer techniques of blood pressure measurement are now well established in the diagnosis and management of adult subjects with hypertension.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundThe development of automatic instrumentation for ambulatory blood pressure monitoring makes it possible to follow the time-course of blood pressure variation over 24 h or more in large groups of individuals. Whenever samples from a reference group of individuals are available, one may construct a prediction interval that is expected to include any single future observation from the reference population, with a specified confidence. Alternatively, the reference interval may consist of a tolerance interval that will include at least a specified proportion of the population with a stated confidence.ObjectiveTo examine prospectively whether a new, combined tolerance–hyperbaric test approach of establishing tolerance intervals for the circadian variability of blood pressure as a function of gestational age and then computing the hyperbaric index as a measure of blood pressure excess provides high sensitivity and specificity in the early identification of pregnant women who subsequently will develop gestational hypertension or preeclampsia.MethodsWe used data sampled for 48 h from 148 normotensive men and women to compute and compare time-specified tolerance and prediction intervals for blood pressure. Once the threshold, given by the upper limit of the tolerance interval, was available, the hyperbaric index, as a measure of blood pressure excess, could be calculated by numerical integration as the total area of any given patient's blood pressure above the threshold. The hyperbaric index, in addition to the duration of excess, could then be used as nonparametric endpoints for assessing hypertension. This combined approach, the tolerance–hyperbaric test, was examined prospectively in the early identification of pregnant women who subsequently will develop gestational hypertension or preeclampsia. We analysed 1494 blood pressure series sampled for 48 h in 124 women with uncomplicated pregnancies and 78 women who developed gestational hypertension or preeclampsia.ResultsSensitivity of the tolerance–hyperbaric test was 93% for women sampled during the first trimester of gestation, and increased up to 99% in the third trimester. Results further indicated lower sensitivity and specificity from other parameters also computed from data sampled by ambulatory monitoring, including the blood pressure load and average values of blood pressure.DiscussionThe results suggested the use of tolerance intervals as the appropriate threshold for the circadian variability of blood pressure, primarily because the practical use of prediction limits was restricted by the need for assumptions of normality and symmetry; also, the prediction intervals could not be considered generally applicable when constructed on the basis of a small sample.ConclusionsDespite the limitations of ambulatory blood pressure monitoring, the tolerance-hyperbaric test represents a reproducible, noninvasive, and highly sensitive test for diagnosing hypertension that has also been validated prospectively for the very early identification of subsequent gestational hypertension and preeclampsia.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundProlonged hypertension in adults has been associated with end-organ damage, in addition to increased morbidity and mortality. Accurate measurement of blood pressure in pediatric and adult patients is imperative for the appropriate diagnosis of hypertension, so that measures may be instituted to prevent these adverse sequelae. Although intermittent office measurement of blood pressure is practiced in most parts of the world, the technique is fraught with problems. Errors during the actual measurement and difficulties in interpretation of the data are well-studied challenges associated with intermittent blood pressure measurements that have been well studied. Ambulatory blood pressure monitoring offers several advantages over intermittent measurement: blood pressure measurements are available over a prolonged period of time (including the sleep period), measurements are not as dependent on observer biases as are intermittent measurements, and in adults the data appear to correlate well to measures of end-organ damage. In children, the ambulatory blood pressure monitor is well tolerated and accurate. This new technology may offer pediatric specialists the opportunity to identify more accurately the child with increased blood pressure, so that preventive measures can be instituted to reduce the well-known morbidity and mortality associated with hypertension.ObjectiveTo review the technical aspects of blood pressure measurement in children, with special attention to the emerging field of ambulatory blood pressure monitoring and its potential use in children.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In contrast to the large number of studies relating high blood pressure to morbidity and mortality in adulthood, relatively few studies evaluating outcomes of children with hypertension have been conducted. Results of recent studies evaluating hypertensive target-organ injury in childhood suggest that early abnormalities, including left ventricular hypertrophy, glomerular hyperfiltration, and rettnopathy, occur more commonly than had formerly been believed, and in children with mild elevations of blood pressure. Ambulatory blood pressure monitoring may be an important tool for use in evaluating hypertensive target organ damage in children and adolescents.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID