Prognostic significance of ambulatory blood pressure.

Measurements of ambulatory blood pressure as an adjunct to casual/clinic blood pressure measurements are currently widely used for the diagnosis and treatment of hypertension. There have been many recent reports on the clinical significance of ambulatory blood pressure. The relationship between ambulatory blood pressure level and target-organ damage uniformly demonstrated on a cross-sectional basis that average ambulatory blood pressure is correlated to target-organ damage. The main limitation of cross-sectional studies, however, is the difficulty of drawing inferences about causality from them. We have been monitoring the prognosis of the Ohasama population and reported that ambulatory blood pressure is superior to casual blood pressure for the prediction of mortality. We also observed that the daytime ambulatory blood pressure is a better predictor for cardiovascular mortality in the general population than is the night-time ambulatory blood pressure. It is widely recognized that casual/clinic blood pressure is less representative of the true blood pressure level than is average ambulatory blood pressure. One reason that clinic blood pressure is a poor predictor of prognosis is that clinic blood pressure includes several biases, including the white-coat effect. For determining white-coat hypertension, measurement of blood pressure in a non-medical setting such as ambulatory blood pressure monitoring is indispensable. We examined the prognostic significance for mortality of white-coat hypertension and reversed white-coat hypertension (clinic blood pressure 相似文献   

Task force IV: Clinical use of ambulatory blood pressure monitoring. Participants of the 1999 Consensus Conference on Ambulatory Blood Pressure Monitoring

OBJECTIVE: To reach a consensus on the clinical use of ambulatory blood pressure monitoring (ABPM). METHODS: A 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 CONSENSUS: The 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. CONCLUSIONS: ABPM 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.     

White-coat hypertension in adults and children.

The measurement of blood pressure in the clinic triggers an altering reaction and a rise in blood pressure in the patient. Such a reaction is usually defined as a 'white-coat effect' or 'white-coat phenomenon', while the coexistence of persistently high office blood pressure with normal blood pressure outside the medical setting is referred to as 'white-coat' or 'office' hypertension. The white-coat effect can be estimated on a beat-to-beat basis using invasive (intra-arterial) or non-invasive methods, or, more commonly, by measuring the difference between office blood pressure and average daytime ambulatory blood pressure. The white-coat effect has little clinical importance because it is not associated with the target-organ damage and prognosis. We found that cardiovascular morbidities of healthy normotensive controls and subjects with white-coat hypertension did not differ. Results of a prospective study with intra-arterial blood pressure monitoring and preliminary prospective data from another group confirm our findings. A recent analysis of our database suggests that we should use a restrictive definition of white-coat hypertension (for example, average daytime blood pressure <130/80 mmHg) in order to identify the minority of subjects with low probabilities of developing a major cardiovascular event in the subsequent years. Also a recent document by the American Society of Hypertension suggests that one should use restrictive upper normal limits of ambulatory blood pressure (i.e., average daytime blood pressure <135 mmHg systolic and 85 mmHg diastolic). We have found that, over a follow-up period of 0.5-6.5 years, 37% of subjects with white-coat hypertension spontaneously evolve into ambulatory hypertension, with accompanying increase in left ventricular mass. The probability of developing ambulatory hypertension increased with the baseline values of ambulatory blood pressure, not of clinic blood pressure. A final answer on the clinical significance of white-coat hypertension will come from very large surveys of the natural history of this condition in the long term. Authors of these longitudinal studies should also compare the response to drug treatment of these subjects with that to life-style-modification measures.     

Role of Ambulatory Blood Pressure Monitoring in Resistant Hypertension

Ambulatory blood pressure monitoring has gained growing popularity in the diagnosis and treatment of essential hypertension for several reasons, such as the lack of the so-called white-coat effect, the greater reproducibility as compared with clinic blood pressure, the ability to provide information on blood pressure phenomena of prognostic value and the closer relationship with the risk of cardiovascular morbidity and mortality. All the above-mentioned main features of ambulatory blood pressure monitoring are also true for resistant hypertension. In addition, however, in resistant hypertension, blood pressure monitoring allows one to precisely define the diagnosis of this clinical condition, by excluding the presence of white-coat hypertension, which is responsible for a consistent number of “false” resistant hypertensive cases. The approach also allows one to define the patterns of blood pressure variability in this clinical condition, as well as its relationships with target organ damage. Finally, it allows one to assess the effects of therapeutic interventions, such as renal nerves ablation, aimed at improving blood pressure control in this hypertensive state. The present paper will critically review the main features of ambulatory blood pressure monitoring in resistant hypertension, with particular emphasis on the diagnosis and treatment of this high-risk hypertensive state.     

Self-measured versus ambulatory blood pressure in the diagnosis of hypertension

OBJECTIVE: We examined to what extent self-measurement of blood pressure at home (HBP) can be an alternative to ambulatory monitoring (ABP) to diagnose white-coat hypertension. METHODS: In 247 untreated patients, we compared the white-coat effects obtained by HBP and ABP. The thresholds to diagnose hypertension were > or = 140/> or = 90 mmHg for conventional blood pressure (CBP) and > or = 135/> or = 85 mmHg for daytime ABP and HBP. RESULTS: Mean systolic/diastolic CBP, HBP and ABP were 155.4/100.0, 143.1/91.5 and 148.1/95.0 mmHg, respectively. The white-coat effect was 5.0/3.5 mmHg larger on HBP compared with ABP (12.3/8.6 versus 7.2/5.0 mmHg; P < 0.001). The correlation coefficients between the white-coat effects based on HBP and ABP were 0.74 systolic and 0.60 diastolic (P < 0.001). With ABP as a reference, the specificity of HBP to detect white-coat hypertension was 88.6%, and the sensitivity was 68.4%. CONCLUSION: Our findings are in line with the recommendations of the ASH Ad Hoc Panel that recommends HBP for screening while ABP has a better prognostic accuracy.     

Significance of white-coat hypertension in older persons with isolated systolic hypertension: a meta-analysis using the International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes population

The significance of white-coat hypertension in older persons with isolated systolic hypertension remains poorly understood. We analyzed subjects from the population-based 11-country International Database on Ambulatory Blood Pressure Monitoring in Relation to Cardiovascular Outcomes database who had daytime ambulatory blood pressure (BP; ABP) and conventional BP (CBP) measurements. After excluding persons with diastolic hypertension by CBP (≥90 mm Hg) or by daytime ABP (≥85 mm Hg), a history of cardiovascular disease, and persons <18 years of age, the present analysis totaled 7295 persons, of whom 1593 had isolated systolic hypertension. During a median follow-up of 10.6 years, there was a total of 655 fatal and nonfatal cardiovascular events. The analyses were stratified by treatment status. In untreated subjects, those with white-coat hypertension (CBP ≥140/<90 mm Hg and ABP <135/<85 mm Hg) and subjects with normal BP (CBP <140/<90 mm Hg and ABP <135/<85 mm Hg) were at similar risk (adjusted hazard rate: 1.17 [95% CI: 0.87-1.57]; P=0.29). Furthermore, in treated subjects with isolated systolic hypertension, the cardiovascular risk was similar in elevated conventional and normal daytime systolic BP as compared with those with normal conventional and normal daytime BPs (adjusted hazard rate: 1.10 [95% CI: 0.79-1.53]; P=0.57). However, both treated isolated systolic hypertension subjects with white-coat hypertension (adjusted hazard rate: 2.00; [95% CI: 1.43-2.79]; P<0.0001) and treated subjects with normal BP (adjusted hazard rate: 1.98 [95% CI: 1.49-2.62]; P<0.0001) were at higher risk as compared with untreated normotensive subjects. In conclusion, subjects with sustained hypertension who have their ABP normalized on antihypertensive therapy but with residual white-coat effect by CBP measurement have an entity that we have termed, "treated normalized hypertension." Therefore, one should be cautious in applying the term "white-coat hypertension" to persons receiving antihypertensive treatment.     

Significance of blood pressure self-measurement as compared with office blood pressure measurement and ambulatory 24-hour blood pressure measurement in pharmacological studies

With the increasing use of blood pressure self-measurement in pharmacological studies, the question arises as to whether this method can replace office blood pressure measurement or ambulatory 24-h blood pressure measurement for testing and comparing the efficacy of antihypertensives. Ambulatory 24-h blood pressure measurement or self-measurement available for analysis can be obtained in 70 to 90% of patients. Self-measurement shows a better correlation with the prognostically relevant ambulatory 24-h blood pressure measurement than office blood pressure measurement for appraising the antihypertensive effect. Although similar antihypertensive effects were found for ambulatory 24-h blood pressure measurement and self-measurement in the group comparison, substantial discrepancies can be observed in the individual patient owing to the different nature of these two methods of measurement. Both ambulatory 24-h blood pressure measurement and self-measurement are superior to office blood pressure measurement in terms of their reproducibility. This increases the sensitivity of clinical studies and reduces the number of cases required. Owing to the white-coat effect, variable compliance and drug holidays and their effects on the efficacy of antihypertensive medication are not detected by office blood pressure measurement and ambulatory 24-h blood pressure measurement. Self-measurement detects drug holidays, which are reflected in an increase of the blood pressure measurement values, and per se promotes compliance. Self-measurements and ambulatory 24-h measurements in pharmacological studies must be regarded as complementary, so that it is appropriate to use both methods whenever possible. Data management, data analysis and monitoring in pharmacological studies are facilitated by instruments with automatic data storage which allows telemonitoring.     

Development of diagnostic thresholds for automated self-measurement of blood pressure in adults. First International Consensus Conference on Blood Pressure Self-Measurement

Blood pressure is usually measured by conventional sphygmomanometry, a procedure fraught with many potential sources of error. Automated techniques of 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 monitoring. First, the distributions of the ambulatory blood pressure in normotensive subjects and in untreated hypertensive patients who had initially been classified on the basis of their conventional blood pressure were studied. Second, epidemiological studies were performed to investigate the distribution of the conventional and ambulatory blood pressures in the population at large. Third, authors of several studies have now validated the preliminary thresholds for ambulatory monitoring against left ventricular hypertrophy, other signs of target-organ damage and the incidence of cardiovascular complications. Finally, authors of clinical trials investigated whether it is beneficial to patients and cost-effective to diagnose and treat hypertension on the basis of ambulatory monitoring rather than under the sole guidance of conventional sphygmomanometry. For systolic/diastolic measurements, the upper limits of normotension include 130/80, 135/85 and 120/70 mmHg for the 24 h, daytime and night-time blood pressures, respectively. Whereas for ambulatory monitoring a large body of evidence currently supports the proposed diagnostic thresholds, for the self-recorded blood pressure, to a large extent, this evidence must still be collected. In pursuing this goal, the methods applied for ambulatory monitoring may serve as a template. On the basis of a meta-analysis of summary statistics of published articles and a meta-analysis of data from individual subjects, 135/85 mmHg is likely to be the upper limit of normality for the self-measured blood pressure. Obviously, this threshold is preliminary and must be further validated in prognostic studies. However, the present proposal could guide clinicians who wish to use self-measurement to refine the diagnosis and the management of hypertension based on conventional sphygmomanometry.     

Determinants of white-coat syndrome assessed by ambulatory blood pressure or self-measured home blood pressure

BACKGROUND: Gender, age, smoking, race, and body mass index have been reported to determine the ambulatory white-coat effect (WCE) and white-coat hypertension (WCH). METHODS: Baseline conventional, day-time ambulatory and self-measured home blood pressure measurements from the THOP trial were used to study the effect of gender, age, body mass index, smoking habits and treatment status on the white-coat syndrome as assessed by ambulatory monitoring or self-measurement. RESULTS: The mean systolic/diastolic WCE was 9.1/6.7 mmHg if based on ambulatory blood pressure and 12.2/8.7 mmHg if based on self-measured blood pressure. The ambulatory WCE was significantly higher in women, in older subjects (65+), in obese subjects, in non-smokers and in patients on antihypertensive drug treatment. The self-measured WCE was significantly higher in women and in non-smokers. Ambulatory WCH was present in 6.6% of the untreated patients and 14.2% had self-measured WCH. The proportion of ambulatory WCH was significantly higher in obese subjects; the proportion of self-measured WCH did not differ by gender, age, body mass index, or smoking habits. CONCLUSIONS: The ambulatory white-coat syndrome was determined by gender, age, body mass index, smoking habits, and treatment status. The self-measured white-coat syndrome was greater than the ambulatory white-coat syndrome but depended less on the determinants under study.     

Cardiovascular risk in white-coat and sustained hypertensive patients

We compared cardiovascular outcome between patients with white-coat and sustained hypertension who had previously participated in the Ambulatory Blood Pressure Monitoring and Treatment of Hypertension (APTH) trial. Baseline characteristics, including office and ambulatory blood pressure (BP), were measured during the 2-month run-in period of the APTH trial. During follow-up, information on the occurrence of major cardiovascular events (death, myocardial infarction, stroke and heart failure), achieved office BP and treatment status was obtained. At entry, 326 patients had sustained hypertension (daytime ambulatory BP ≥140 mmHg systolic and/or ≥90 mmHg diastolic) and 93 had daytime ambulatory BP below these limits and were classified as white-coat hypertensives. During 2088 patientyears of follow-up (median follow-up 5.3 years), all major cardiovascular events ( n = 22) occurred in the patients with sustained hypertension (rate 12.7 per 1000 patient-years, p = 0.02 for between-group difference). Furthermore, multiple Cox regression confirmed that after adjustment for important covariables, daytime ambulatory BP - but not office BP at entry - significantly and independently predicted cardiovascular outcome. After additional adjustment for office BP, daytime ambulatory BP still predicted the occurrence of major cardiovascular events. Although white-coat hypertension was less frequently associated with antihypertensive drug treatment during follow-up, it carried a significantly better prognosis than sustained hypertension.     

White-coat hypertension: not guilty when correctly defined

The coexistence of persistently high office blood pressure with normal blood pressujre outside the medical setting is often referred to as 'white-coat', 'office' or 'isolated clinic' hypertension. The definition of normal blood pressure outside the medical setting is controversial. In our experience, not only the prevalence of white-coat hypertension, but also left ventricular mass measured echocardiographically and the prevalence of left ventricular hypertrophy in this condition markedly vary on going from more restrictive (lower) to more liberal (higher) limits of ambulatory blood pressure normalcy over quite a narrow range. In a prospective study, cardiovascular morbidities of healthy normotensive controls and subjects with white-coat hypertension did not differ. A more recent analysis of our database supports the use of qujite a restrictive definition of white-coat hypertension (average daytime blood pressure < 130/80 mmHg) in order to identify the minority of subjects who have a low risk of cardiovascular morbid events during the subsequent years. A recent document published by the American Society of Hypertension suggests that slightly higher upper limits of ambulatory blood pressure normalcy (i.e. average daytime blood pressure < 135 mmHg systolic and 85 mmHg diastolic) should be used. In a follow-up study by our group, 37% of subjects with white-coat hypertension spontaneously evolved into cases of ambulatory hypertension, with accompanying increases in left ventricular mass. In that study, the probability of a subject developing ambulatory hypertension increased with the baseline values of ambulatory blood pressure and it was quite low (20%) for those with daytime blood pressures below 130/80 mmHg. In two recent controlled studies, the rate of development of ambulatory hypertension over time for untreated subjects did not differ between the normotensive control group and the group with white-coat hypertension. A final answer regarding the clinical significance of white-coat hypertension will come from very large surveys of the natural history of this condition in the long term. For now, we suggest a verdict of innocence for white-coat hypertension when low values of daytime ambulatory blood pressure (i.e. < 130/80 mmHg) and absence of organ lesions and other risk factors coexist.     

Ambulatory measurement of the QKD interval normalized to heart rate and systolic blood pressure to assess arterial distensibility--value of QKD(100-60).

BACKGROUND: Reduced distensibility of large arteries plays an important role in cardiovascular risk. Determination of the QKD interval during the ambulatory measurement of blood pressure enables calculation of an index of arterial distensibility. This index, the QKD(100-60), is the theoretical value of QKD at systolic blood pressure of 100mmHg and heart rate of 60bpm obtained from the linear bivariate relationship linking QKD, systolic blood pressure and heart rate on a hundred successive values measured over 24h. This study was designed to examine the relationship between QKD and QKD(100-60) on heart rate and systolic function of the left ventricle, the two parameters governing the pre-ejection time which is part of the QKD interval. METHODS AND RESULTS: In a population of 203 untreated hypertensive patients having benefited from an ambulatory measurement of blood pressure over 24h with QKD monitoring and an M-mode echocardiographic recording of the left ventricle, we found that although mean QKD was linked to heart rate and systolic function of the left ventricle, QKD(100-60) was not. It fell significantly with age, and to a greater extent in the sustained hypertensives than in white-coat hypertensives. CONCLUSION: QKD(100-60) constitutes an index of arterial distensibility independent of the pre-ejection time. As an adjunct to the ambulatory measurement of blood pressure, its determination is simple and completely automatic, thus eliminating observer bias.     

White-Coat Resistant Hypertension

The aim of this study was to evaluate whether sustained hypertensives with high clinic blood pressure, despite multiple drug treatment, show a true resistant hypertension or a “white-coat effect,” and whether the pretreatment white-coat effect is maintained despite pharmacological therapy. The occurrence of resistant hypertension was determined in 250 consecutive essential hypertensives who had had an ambulatory blood pressure monitoring before treatment assignment. Twenty-seven of 250 hypertensives with persistently high clinic blood pressure despite 3 months of adequate pharmacological therapy underwent further ambulatory blood pressure monitoring. Using our internal standards, seven patients had a true resistant hypertension whereas 20 subjects showed a large white-coat effect (white-coat resistant hypertension), ie, high clinic blood pressure (>140/90) but “normal” ambulatory daytime (<139/90 mm Hg) and 24 h (135/85 mm Hg) blood pressure. Using other cutoff points for ambulatory blood pressure, 134/90 and 135/85 mm Hg for daytime blood pressure, 10 and 13 patients, respectively, were reclassified as true resistant hypertensives and 17 and 14, respectively, were white-coat resistant hypertensives. Interestingly, in white-coat resistant hypertensives the large differences between clinic and ambulatory daytime blood pressure (white-coat effect), recorded before treatment assignment, were not affected by drugs and remained constant over time. Left ventricular mass index in white-coat resistant hypertensives was significantly lower than in truly resistant hypertensives, suggesting that prognosis could differ between these groups. In this study, using either our internal standards or some other cutoffs reported in the literature, the white-coat phenomenon was an important cause of resistant hypertension. The use of ambulatory blood pressure monitoring in these patients may avoid misdiagnosis of resistant hypertension, unnecessary overtreatment, and expensive procedures to look for possible secondary hypertension.     

Components of arterial stiffness in a population of 65-year-old subjects: PROOF study

OBJECTIVES: Arterial stiffness increases with age, diabetes and hypertension, and is linked to the occurrence of cardiovascular complications, independently of traditional risk factors. The important influence of age and blood pressure on arterial stiffness and cardiovascular risk complicates analysis of factors involved in increased arterial stiffness. Study of the PROOF cohort supplied further information by analysis of subjects of identical age using a method that eliminates the immediate influence of blood pressure on pulse wave velocity. METHODS: The PROOF cohort comprised 1011 subjects, aged 65 years, from the city of Saint-Etienne (France). All benefited from 24-h ambulatory blood pressure monitoring coupled with measurement of QKD interval. Ambulatory Arterial Stiffness Index and QKD(100-60), were calculated for each recording. Measurements were performed again 2 years later. RESULTS: Height-predicted QKD(100-60) was correlated with pulse pressure and the presence of diabetes. We found no significant influence of sex, current smoking or total serum cholesterol. Ambulatory Arterial Stiffness Index, whether it was height predicted or not, only had a significant relationship with blood pressure. Two years later, although the QKD(100-60) remained stable for the overall population, it was reduced in the normotensive subjects. Over the whole population, there was a correlation between the changes in 24-h systolic blood pressure and QKD(100-60). CONCLUSION: QKD(100-60), an isobaric index of arterial stiffness, is significantly linked to blood pressure and blood sugar levels in a population of 65-year-old subjects. Two years later, the arterial stiffness increased significantly in the normotensive subjects, whereas it remained stable in the hypertensive subjects.     

Risk of cardiovascular disease in relation to achieved office and ambulatory blood pressure control in treated hypertensive subjects

OBJECTIVE: We investigated the prognostic impact of 24-h blood pressure control in treated hypertensive subjects. BACKGROUND: There is growing evidence that ambulatory blood pressure improves risk stratification in untreated subjects with essential hypertension. Surprisingly, little is known on the prognostic value of this procedure in treated subjects. METHODS: Diagnostic procedures including 24-h noninvasive ambulatory blood pressure monitoring were undertaken in 790 subjects with essential hypertension (mean age 48 years) before therapy and after an average follow-up of 3.7 years (2,891 patient-years). RESULTS: At the follow-up visit, 26.6% of subjects achieved adequate office blood pressure control (<140/90 mm Hg), and 37.3% of subjects achieved adequate ambulatory blood pressure control (daytime blood pressure <135/85 mm Hg). Months or years after the follow-up visit, 58 patients suffered a first cardiovascular event. Event rate was lower (0.71 events/100 person-years) among the subjects with adequate ambulatory blood pressure control than among those with higher blood pressure levels (1.87 events/100 person-years) (p = 0.0026). Ambulatory blood pressure control predicted a lesser risk for subsequent cardiovascular disease independently of other individual risk factors (RR 0.36; 95% confidence intervals: 0.18 to 0.70; p = 0.003), including age, diabetes and left ventricular hypertrophy. Office blood pressure control was associated with a nonsignificant lesser risk of subsequent events (RR 0.63; 95% confidence intervals: 0.31 to 1.31; p = NS). In-treatment ambulatory blood pressure was more potent than pre-treatment blood pressure for prediction of subsequent cardiovascular disease. CONCLUSIONS: Ambulatory blood pressure control is superior to office blood pressure control for prediction of individual cardiovascular risk in treated hypertensive subjects.     

Hypertensive Pregnancy Disorders and Future Renal Disease

Ambulatory blood pressure (BP) monitoring provides valuable information on a person’s BP phenotype. Abnormal ambulatory BP phenotypes include white-coat hypertension, masked hypertension, nocturnal nondipping, nocturnal hypertension, and high BP variability. Compared to people with sustained normotension (normal BP in the clinic and on ambulatory BP monitoring), the limited research available suggests that the risk of developing sustained hypertension (abnormal BP in the clinic and on ambulatory BP monitoring) over 5 to 10 years is approximately two to three times greater for people with white-coat or masked hypertension. More limited data suggest that nondipping might predate hypertension, and no studies, to our knowledge, have examined whether nocturnal hypertension or high ambulatory BP variability predict hypertension. Ambulatory BP monitoring may be useful in identifying people at increased risk of developing sustained hypertension, but the clinical utility for such use would need to be further examined.     

Ambulatory blood pressure monitoring: technique and application in the study of cardiac dysfunction and congestive heart failure

Ambulatory blood pressure monitoring has become a widely used method of blood pressure and heart rate evaluation in the free-living subject. Recently, ambulatory monitoring has become covered by Medicare for the evaluation of "white-coat" hypertension. Although the technique provides only intermittent readings throughout the 24-hour period, average blood pressures obtained in this way correlate well with a variety of hypertensive disease processes and are also a better prognostic marker for future cardiovascular events than office blood pressure. Ambulatory blood pressure averages also correlate well with indices of diastolic dysfunction. In patients with congestive cardiac failure and systolic dysfunction, ambulatory monitoring suggests an impaired circadian blood pressure profile with high nocturnal blood pressure. Further research is needed on the relationship between ambulatory blood pressure and cardiac dysfunction, as well as the impact of observed circadian blood pressure changes on outcome. (c)2001 CHF, Inc.     

Ambulatory blood pressure monitoring and echocardiography—Noninvasive techniques for evaluation of the hypertensive patient

Clinic blood pressure measurements have only limited ability to determine which hypertensive patients are at greatest risk of cardiovascular events. Ambulatory blood pressure monitoring allows for noninvasive measurement of blood pressure throughout the 24-hour period. This may help to clarify discrepancies between blood pressure values obtained in and out of the clinic and confirm the presence of white-coat hypertension, broadly defined as an elevated clinic blood pressure but a normal ambulatory blood pressure. Ambulatory blood pressure values have been shown to have a better relationship to cardiovascular morbidity and mortality and end-organ damage than clinic blood pressure values. Further, patients with white-coat hypertension appear to be at greater risk of cardiovascular morbidity and end-organ damage than a normotensive population, although they are at less overall risk than a hypertensive population. Hypertensive heart disease is characterized by diastolic dysfunction, increased left ventricular mass, and coronary flow abnormalities. Left ventricular hypertrophy increases the risk of coronary heart disease, congestive heart failure, stroke, ventricular arrhythmias, and sudden death. A variety of invasive and noninvasive techniques are described herein that measure left ventricular mass, diastolic function, and coronary blood flow abnormalities. Most antihypertensive treatments promote regression of left ventricular hypertrophy and reversal of diastolic dysfunction, which may decrease symptoms of congestive heart failure and improve survival. Copyright © 1999 by W.B. Saunders Company

Progress in Cardiovascular Diseases, Vol. 41, No. 6 (May/June), 1999: pp 397-440     

White-coat effect in normotension and hypertension

OBJECTIVES: The difference between clinic and daytime ambulatory blood pressure is referred to as the white-coat effect. In this study, we investigated (i) the magnitude of the white-coat effect in subjects with different daytime ambulatory blood pressure levels, and (ii) the association of the white-coat effect with left ventricular mass. METHODS: A total of 1581 subjects underwent clinic blood pressure readings, 24-h ambulatory blood pressure monitoring and left ventricular echocardiographic assessment. Their mean daytime systolic blood pressure varied from 88.0 to 208.9 mmHg and their mean daytime diastolic blood pressure from 40.3 to 133.0 mmHg. RESULTS: A negative correlation was found between the systolic or diastolic white-coat effect and the systolic or diastolic daytime ambulatory blood pressure (r = -0.22, P < 0.000 and r = -0.50, P < 0.000, respectively). Left ventricular mass significantly correlated with ambulatory blood pressure (P < 0.001), but there was no association between left ventricular mass and clinic blood pressure or white-coat effect. Furthermore, the white-coat effect was reversed at the highest level of systolic or diastolic daytime ambulatory blood pressure (systolic over 170 mmHg or diastolic over 100 mmHg) when systolic or diastolic daytime ambulatory blood pressure was higher than systolic or diastolic clinic blood pressure (ambulatory blood pressure hypertension). CONCLUSIONS: The white-coat effect shows an inverse association with daytime ambulatory blood pressure level (systolic or diastolic), being significantly more prominent for levels below 140/80 mmHg for systolic/diastolic daytime ambulatory blood pressure and reversed with daytime ambulatory blood pressure levels above 170/100 mmHg.     

Prognostic significance of self-measurements of blood pressure

BACKGROUND: Self-measurements of blood pressure may offer some advantage in diagnostic and therapeutic evaluation and in management of patients. However, the most important limitation of self-measurement is that there are limited data available about the prognostic value of this information. RESULTS: Authors of several previous reports demonstrated that self-measurement reflects target-organ damage better than does casual measurement of blood pressure. So far, investigators in Tecumseh and Ohasama studies have provided pilot data on prognostic value of self-measurements. Investigators in Ohasama study demonstrated that self-measurements predict cardiovascular morbidity and mortality and all-cause mortality better than do casual measurements of blood pressure. Investigators in Tecumseh study demonstrated that self-measurement can predict future development of sustained hypertension and of diastolic dysfunction. These preliminary results suggest that self-measurements have strong predictive power for endpoints and surrogate measures of cardiovascular target-organ damage. CONCLUSION: The final answer on the prognostic significance of self-measurement has not been given. Prognostic studies designed to compare casual measurement of blood pressure, self-measurement, and ambulatory blood pressure monitoring are needed.