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:

Ambulatory blood pressure (ABP) has only rarely been employed in population studies because of the difficulty posed by the greater complexity of this technique. The cross-sectional studies that have been published, however, have allowed a number of conclusions to be drawn. One, 24 h average blood pressure of populations is significantly but not closely related to office blood pressure, which thus can not predict accurately daily-life values of blood pressure. Two, 24 h average blood pressure is usually less than office blood pressure, the discrepancy increasing with the increase in office values and being of magnitude several mmHg at the office blood pressure of 140/90 mmHg (systolic/diastolic) Three, ABP in women is somewhat less than that in men and ABP for both sexes increases less with aging than does office blood pressure. Four, a circadian profile of blood pressure consisting in values that are much lower at night than are those during daytime characterizes both sexes and all ages with the possible exception of individuals aged 75 years and more, in whom the nocturnal hypotension appears to be attenuated. A similar attenuation has been found for blacks in comparison with whites. The upper limit of normality of ABP has not yet been defined conclusively, although 24 h average values ≤ 125/80 mmHg are almost invariably regarded as normal. Normality of ABP should be defined, however, by longitudinal population studies in which ambulatory values are related to prognosis. One of these studies has already been published and others will be completed in the near future.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo reach a consensus on ambulatory blood pressure (ABP) as a predictor of target-organ damage (TOD), morbidity and mortality.MethodThe members of task force III wrote this article in preparation for the Seventh International Consensus Conference (23–25 September 1999). This article was amended after the meeting to reflect the consensus reached at the conference.Points of consensusIn most studies, TOD in essential hypertension was more closely associated with ABP than it was with clinic blood pressure, the mean weighted correlation coefficients for the relationship of left ventricular mass with blood pressure being 0.50/0.44 (24 h systolic/diastolic blood pressure) and 0.35/0.32 (clinic systolic/diastolic blood pressure), respectively. The above correlation coefficients vary among studies, possibly because of different standardizations of clinic blood pressure measurements and ways of selecting subjects, among other reasons. The closeness of the association between clinic blood pressure and left ventricular mass increases with the numbers of clinic measurements of blood pressure and visits to a clinic. Thus, the variance of left ventricular mass explained by ABP in addition to that explained by clinic blood pressure diminishes with the number of clinic blood pressure readings. The proportion of variability of left ventricular mass that is directly accounted for by the day-night difference in blood pressure is 15% at the most. Thus, the advantage of ABP over clinic blood pressure appears to be, at least in part, a result of the greater number of measurements over the 24 h. It might also depend, however, on the information offered by ambulatory blood pressure monitoring (ABPM) on daily-life variations in blood pressure. TOD appears to be more closely associated with ABP than it is with clinic blood pressure for the subjects with reproducible ABP tracings, but not for those with poorly reproducible tracings. The probability of developing sustained clinic hypertension at follow-up seems to be better predicted by clinic blood pressure on several occasions over a 6-month period than it is by ABP at baseline, although, when also ABPM is repeatedly performed at follow-up, its ability to predict clinical outcomes of hypertensive patients remains superior to that of repeated clinic blood pressure measurements. ABPM of the elderly appears feasible and is tolerated well. A blunted day-night fall in blood pressure ('non-dipping') seems to be harmful, while evidence regarding the potentially harmful effect of extreme dipping is still limited. Authors of the Syst-Eur study recently demonstrated the prognostic value of ambulatory systolic blood pressure and in particular, of night-time blood pressure, in assessing old subjects with isolated systolic hypertension. The assessment of variability of blood pressure has been shown to provide a further prediction of cardiovascular risk and the potentially prognostic value of beat-to-beat variability assessed non-invasively (using a Finapres or Portapres device) needs further study. In the published event-based studies, the prognostic value of ABP recorded during a single session was superior to that of clinic blood pressure. Since the authors of published event-based prognostic studies compared ABP with only a few clinic measurements of blood pressure, it is not known how many visits or measurements of blood pressure (and at what cost) would equate to a single session of ABPM in terms of prediction of cardiovascular events. ABPM might allow one to identify a subset with 'normal' ABP (white-coat or isolated clinic hypertension). Daytime ABP levels < 135 mmHg systolic and 85 mmHg diastolic can be defined as normal and values < 130/80 mmHg could be defined as optimal. Cardiovascular risk for subjects with normal ABP seems to be lower than that for those with abnormally high ABP. Long-term observational and intervention studies concerning subjects with white-coat hypertension are needed. Among subjects with abnormally high ABP, cardiovascular risk seems to be inversely associated with the day-night difference in blood pressure and directly associated with ambulatory pulse pressure. The potential additional prognostic value of self-measured blood pressure needs further investigation.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

ObjectiveTo reach a consensus on the clinical use of ambulatory blood pressure monitoring (ABPM).MethodsA task force on the clinical use of ABPM wrote this overview in preparation for the Seventh International Consensus Conference (23–25 September 1999, Leuven, Belgium). This article was amended to account for opinions aired at the conference and to reflect the common ground reached in the discussions.Points of consensusThe Riva Rocci/Korotkoff technique, although it is prone to error, is easy and cheap to perform and remains worldwide the standard procedure for measuring blood pressure. ABPM should be performed only with properly validated devices as an accessory to conventional measurement of blood pressure. Ambulatory recording of blood pressure requires considerable investment in equipment and training and its use for screening purposes cannot be recommended. ABPM is most useful for identifying patients with white-coat hypertension (WCH), also known as isolated clinic hypertension, which is arbitrarily defined as a clinic blood pressure of more than 140 mmHg systolic or 90 mmHg diastolic in a patient with daytime ambulatory blood pressure below 135 mmHg systolic and 85 mmHg diastolic. Some experts consider a daytime blood pressure below 130 mmHg systolic and 80 mmHg diastolic optimal. Whether WCH predisposes subjects to sustained hypertension remains debated. However, outcome is better correlated to the ambulatory blood pressure than it is to the conventional blood pressure. Antihypertensive drugs lower the clinic blood pressure in patients with WCH but not the ambulatory blood pressure, and also do not improve prognosis. Nevertheless, WCH should not be left unattended. If no previous cardiovascular complications are present, treatment could be limited to follow-up and hygienic measures, which should also account for risk factors other than hypertension. ABPM is superior to conventional measurement of blood pressure not only for selecting patients for antihypertensive drug treatment but also for assessing the effects both of non-pharmacological and of pharmacological therapy. The ambulatory blood pressure should be reduced by treatment to below the thresholds applied for diagnosing sustained hypertension. ABPM makes the diagnosis and treatment of nocturnal hypertension possible and is especially indicated for patients with borderline hypertension, the elderly, pregnant women, patients with treatment-resistant hypertension and patients with symptoms suggestive of hypotension. In centres with sufficient financial resources, ABPM could become part of the routine assessment of patients with clinic hypertension. For patients with WCH, it should be repeated at annual or 6-monthly intervals. Variation of blood pressure throughout the day can be monitored only by ABPM, but several advantages of the latter technique can also be obtained by self-measurement of blood pressure, a less expensive method that is probably better suited to primary practice and use in developing countries.ConclusionsABPM or equivalent methods for tracing the white-coat effect should become part of the routine diagnostic and therapeutic procedures applied to treated and untreated patients with elevated clinic blood pressures. Results of long-term outcome trials should better establish the advantage of further integrating ABPM as an accessory to conventional sphygmomanometry into the routine care of hypertensive patients and should provide more definite information on the long-term cost-effectiveness. Because such trials are not likely to be funded by the pharmaceutical industry, governments and health insurance companies should take responsibility in this regard.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

TerminologyTwo terms are in current use to describe patients whose blood pressures are high only in a medical setting (white-coat hypertension and isolated office or clinic hypertension). The term white-coat effect is also commonly used to describe the pressor response to the clinic setting.DefinitionsWhite-coat hypertension is generally defined as a persistently elevated clinic blood pressure in combination with a normal ambulatory blood pressure (ABP). There is disagreement regarding the optimal cutoff point for ABP. The white-coat effect is operationally defined as the difference between the clinic blood pressure and daytime ABP.Prevalence of white-coat hypertensionThis varies according to the definition of white-coat hypertension and the population studied, but is approximately 20% among mild hypertensives, and increases with age.Metabolic and biochemical aspectsAuthors of some studies have suggested that white-coat hypertension is associated with metabolic abnormalities such as hyperlipidemia that lead to an increase in cardiovascular risk, but most have not found this.Target-organ damageSeveral measures of target-organ damage have been compared among normotensives, white-coat hypertensives, and sustained hypertensives; these include left ventricular mass, microalbuminuria, and carotid atherosclerosis. In general, target-organ damage in white-coat hypertension is less than that in sustained hypertension, but in some studies it has been found to be more prevalent than in normotensives.Morbidity and mortalityAuthors of a relatively small number of prospective studies have concluded that white-coat hypertensives have a lower risk of morbidity than do sustained hypertensives, but a larger number have drawn the more general conclusion that, when there is a discrepancy between the clinic blood pressure and ABP, the prognosis is more closely related to the ABP.ManagementWhen white-coat hypertensives are prescribed antihypertensive medication there is usually a decrease in clinic blood pressure, but little or no change in ABP. Thus drug treatment is not necessarily indicated. Another issue is the follow-up of white-coat hypertensives; there is general agreement that blood pressure outside the office should be monitored indefinitely. Some patient may have been wrongly classified as white-coat hypertensives, and others may progress to develop sustained hypertension.

ISSN:1359-5237    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundSelf-monitoring of the blood pressure by patients at home or in other nonclinical settings has become increasingly common in recent years. This phenomenon has been fueled in part by the increase in availability of automatic sphygmomanometers, which are now both affordable and easy for patients to use.Benefits of self-monitoringSelf-monitoring of the blood pressure can be an important adjunct to management of hypertension. The technique allows patients to participate more in their care. Self-measured values of blood pressure are more likely to be representative of the average daily blood pressure than is a clinic measurement and may be better related to hypertensive involvement of target organs and cardiovascular morbidity than is the clinic blood pressure. Finally, the self-monitoring of blood pressure has the potential to reduce the costs of hypertension-related care.Limitations of self-monitoringThere are several issues that prevent the more widespread use of self-monitoring of the blood pressure in clinical practice. First, devices marketed for use by patients have advanced technically during the 1990s, but many have not been subjected to rigorous clinical validation for precision and reliability (e.g. in terms of Association for the Advancement of Medical Instrumentation and British Hypertension Society guidelines). It is recommended that devices for measuring blood pressure used by patients at home be subjected to the same validation processes as those that are applied to ambulatory recordings. Second, although the upper limits of normal for self-monitored blood pressure of a general population can be defined statistically (it is approximately 135/85 mmHg), it is not yet possible to determine the normal self-monitored blood pressure because these values must be linked to classical clinical cardiovascular endpoints or outcomes. Third, the relationships among self-monitored, clinic, and ambulatory blood pressures are defined for some populations but their behaviors according to age, sex, ethnicity, and treatment status require further study. Fourth, several different schedules for self-monitoring of the blood pressure by patients have been used in clinical research and practice. It will be necessary to determine the optimal schedule and number of recordings required when patients perform self-monitoring of the blood pressure. Fifth, self-monitoring of the blood pressure in clinical trials of antihypertensive therapies is certainly feasible but has typically not been included in their design, either by investigators or by the pharmaceutical sponsors. Sixth, there have been data suggesting that self-monitoring of the blood pressure reduces the comprehensive costs associated with hypertension care on an annual basis. However, since most work on the economic impact of self-monitoring of the blood pressure has been performed in managed-care environments in the USA, it is not known whether this reduction in healthcare costs would be applicable to other types of practice environments on a worldwide basis.ConclusionsSelf-monitoring of the blood pressure is at present useful as an adjunct measurement for the management of hypertensive patients and might provide benefits in clinical trials of antihypertensive therapy. Nevertheless, the available data on self-monitoring of the blood pressure are inadequate as grounds for clinicians to make primary diagnostic or therapeutic decisions and should not override the blood pressure obtained by clinical measurement or via ambulatory monitoring.

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

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