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.     

Diagnostic thresholds for ambulatory blood pressure monitoring based on 10-year cardiovascular risk

Current diagnostic thresholds for ambulatory blood pressure (ABP) mainly rely on statistical parameters derived from reference populations. We determined an outcome-driven reference frame for ABP measurement. We performed 24-h ABP monitoring in 5682 participants (mean age 59.0 years; 43.3% women) enrolled in prospective population studies in Copenhagen, Denmark; Noorderkempen, Belgium; Ohasama, Japan; and Uppsala, Sweden. In multivariate analyses, we determined ABP thresholds, which yielded 10-year cardiovascular risks similar to those associated with optimal (120/80 mmHg), normal (130/85 mmHg), and high (140/90 mmHg) blood pressure on office measurement. Over 9.7 years (median), 814 cardiovascular end points occurred, including 377 strokes and 435 cardiac events. Systolic/diastolic thresholds for optimal ABP were 118.3/74.2 mmHg for 24 h, 121.6/78.9 mmHg for daytime, and 104.7/65.3 mmHg for nighttime. Corresponding thresholds for normal ABP were 124.3/76.8, 129.9/82.6, and 111.6/68.1 mmHg, respectively, and those for ambulatory hypertension were 130.3/79.4, 138.2/86.4, and 118.5/70.8 mmHg. After rounding, approximate thresholds for optimal ABP amounted to 115/75 mmHg for 24 h, 120/80 mmHg for daytime, and 105/65 mmHg for nighttime. Rounded thresholds for normal ABP were 125/75, 130/85, and 110/70 mmHg, respectively, and those for ambulatory hypertension were 130/80, 140/85, and 120/70 mmHg. In conclusion, population-based outcome-driven thresholds for optimal and normal ABP are lower than those currently proposed by hypertension guidelines.     

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.     

Effects of age on hypertensive status in patients with chronic kidney disease

OBJECTIVE: To evaluate effect of age on hypertensive status in chronic kidney disease (CKD). METHODS: We studied 459 prevalent CKD patients (stages 2-5, no dialysis), grouped by age (< 55, 55-64, 65-74, >or= 75 years), undergoing clinical blood pressure (CBP) and ambulatory blood pressure (ABP) measurement. RESULTS: Prevalence of diabetes, left ventricular hypertrophy and previous cardiovascular disease progressively increased with aging; glomerular filtration rate (GFR) and hemoglobin decreased. Achievement of CBP target decreased from 16% in patients < 55 years to 6% in those >or= 75 years (P = 0.023). ABP 24-h systolic rose while diastolic decreased, with a consequent pulse pressure increase from 45 +/- 8 to 65 +/- 14 mmHg (P < 0.0001). Age, proteinuria, diabetes, cardiovascular disease and anemia but not GFR predicted higher 24-h pulse pressure. CBP overestimated systolic/diastolic daytime ABP by 14 +/- 18/7 +/- 11 mmHg on average, a greater difference in older than younger groups (P < 0.005). Conversely, CBP night-time ABP difference did not vary among groups (24 +/- 20/16 +/- 11 mmHg). These age-dependent differences determined a rising prevalence of white-coat hypertension (from 19 to 40%, P = 0.001) and night/day ratio of at least 0.9 (from 43 to 66%, P = 0.0004). Age, diabetes, left ventricular hypertrophy and anemia but not GFR predicted nondipping status. Among the oldest patients, 13% had diastolic CBP below 70 mmHg, with 48% below the corresponding values of daytime (< 69 mmHg) or night-time ABP (< 60 mmHg). CONCLUSION: In CKD, prevalence of white-coat hypertension, nondipping status and potentially dangerous low diastolic ABP increases with aging. This suggests wider use of ABP monitoring in older patients and need for trials addressing identification of an age-specific blood pressure target.     

Comparison of awake ambulatory blood pressure and automated office blood pressure using linear regression analysis in untreated patients in routine clinical practice

The recent American hypertension guidelines recommended a threshold of 130/80 mmHg to define hypertension on the basis of office, home or ambulatory blood pressure (BP). Despite recognizing the potential advantages of automated office (AO)BP, the recommendations only considered conventional office BP, without providing supporting evidence and without taking into account the well documented difference between office BP recorded in research studies versus routine clinical practice, the latter being about 10/7 mmHg higher. Accordingly, we examined the relationship between AOBP and awake ambulatory BP, which the guidelines considered to be a better predictor of future cardiovascular risk than office BP. AOBP readings and 24‐hour ambulatory BP recordings were obtained in 514 untreated patients referred for ambulatory BP monitoring in routine clinical practice. The relationship between mean AOBP and mean awake ambulatory BP was examined using linear regression analysis with and without adjustment for age and sex. Special attention was given to the thresholds of 130/80 and 135/85 mmHg, the latter value being the recognized threshold for defining hypertension using awake ambulatory BP, home BP and AOBP in other guidelines. The mean adjusted AOBP of 130/80 and 135/85 mmHg corresponded to mean awake ambulatory BP values of 132.1/81.5 and 134.4/84.6 mmHg, respectively. These findings support the use of AOBP as the method of choice for determining office BP in routine clinical practice, regardless of which of the two thresholds are used for diagnosing hypertension, with an AOBP of 135/85 mmHg being somewhat closer to the corresponding value for awake ambulatory BP.     

Office versus Ambulatory (OvA) recording of blood pressure, a European multicenter study: inclusion and early follow-up characteristics

Only a few large prospective trials intended to address the question of whether management of hypertensive patients should be guided by office (OBP) or ambulatory blood pressure (ABP) and whether fatal and nonfatal cardiovascular events are better predicted by ABP than they are by OBP are going on. Office versus Ambulatory (OvA) recording of blood pressure, a European multicenter study, is a multicenter prospective, 10 000 patient-years follow-up study of treated essential hypertension designed to correlate blood pressure to prognosis, blood pressure being defined either by ABP or OBP. Early in 1997, inclusion was stopped (n = 2224 inclusions, 48.3% women, aged 56.8 +/- 13.1 years) because the required number had been exceeded. Inclusion data reveal that OBP (152.9 +/-21.2/92.7 +/- 10.9 mmHg) of a large portion of patients remains high, although patients had been treated for at least 3 months with antihypertensive drugs. Mean 24 h ABP averaged 133.3 +/-15.9/84.0 +/-11.0 mmHg and 24 h blood pressure and heart rate profiles, large differences in drug treatment, apparatus, type of patients, and patients' activities notwithstanding, were like those expected from well-controlled studies. Risk profile was not particularly high. Evolution of OBP, ABP and electrocardiographic and echocardiographic indices of left ventricular hypertrophy indicate that reeductions of the OBP, ABP, and electrocardiographic indices of left ventricular hypertrophy had occurred after 12 months, after 24 months follow-up there was no longer any further change for most parameters. In conclusion, analysis of inclusion and preliminary follow-up data indicates that the OvA study is running well and that it is likely that final analysis of the data and events from the OvA study will lead to an answer to the study question of whether ABP monitoring is better suited than is OBP to deal with management of the treated hypertensive patient.     

Identification of subjects with white-coat hypertension and persistently normal ambulatory blood pressure

OBJECTIVE: To assess the spontaneous changes in clinic blood pressure, ambulatory blood pressure (ABP) and left ventricular structure in untreated subjects with white-coat hypertension (WCH). DESIGN: A prospective observational study. PATIENTS AND METHODS: In 83 untreated subjects with WCH, 24 h non-invasive ABP monitoring and echocardiographic studies of the left ventricle were repeated after 0.5-6.5 years (mean 2.5) in the absence of antihypertensive drug treatment. WCH was defined by an average daytime ABP < 131/86 mmHg in women and < 136/87 mmHg in men. Ambulatory hypertension was defined by higher ABP values. RESULTS: In the whole population, the clinic blood pressure, ABP and left ventricular mass did not change from baseline to the follow-up visit, whereas the peak A: peak E ratio (where A is the velocity of transmitral blood flow after atrial contraction and E is the velocity during passive left ventricle filling) increased from 0.86 to 0.93. Sixty-three per cent of subjects remained in the WCH category at follow-up study; the remaining 37% shifted to the ambulatory hypertension category. The former group showed no changes in clinic blood pressure, ABP, left ventricular mass and peak A: peak E ratio. The clinic blood pressure of those who developed ambulatory hypertension did not change, whereas their ABP and peak A: peak E ratio increased and their left ventricular mass increased slightly but not significantly. The left ventricular mass increased from baseline to follow-up study by 6.2% in those who developed ambulatory hypertension and decreased by 1.6% in those who remained in the WCH category. The changes in left ventricular mass were associated with the changes in average 24 h systolic blood pressure, but not with the changes in clinic blood pressure. In a stepwise logistic regression analysis, average daytime diastolic blood pressure was the sole variable to enter the model and the probability of ambulatory hypertension at follow-up study was 20.0%percnt; in those with basal daytime ABP <130/80 mmHg, versus 81% in those with higher basal daytime blood pressure levels. CONCLUSION: After 0.5-6.5 years, WCH spontaneously evolved into ambulatory hypertension in 37% of subjects, with an accompanying rise in left ventricular mass. The probability of ambulatory hypertension increased with the baseline values of ABP, rather than with those of clinic blood pressure. WCH might be a prehypertensive state (particularly in subjects with higher baseline ABP levels) and should be defined by low levels of daytime ABP, possibly lower than 130/80 mmHg.     

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.     

Prognostic superiority of daytime ambulatory over conventional blood pressure in four populations: a meta-analysis of 7,030 individuals

OBJECTIVE: To investigate the multivariate-adjusted predictive value of systolic and diastolic blood pressures on conventional (CBP) and daytime (10-20 h) ambulatory (ABP) measurement. METHODS: We randomly recruited 7,030 subjects (mean age 56.2 years; 44.8% women) from populations in Belgium, Denmark, Japan and Sweden. We constructed the International Database on Ambulatory blood pressure and Cardiovascular Outcomes. RESULTS: During follow-up (median = 9.5 years), 932 subjects died. Neither CBP nor ABP predicted total mortality, of which 60.9% was due to noncardiovascular causes. The incidence of fatal combined with nonfatal cardiovascular events amounted to 863 (228 deaths, 326 strokes and 309 cardiac events). In multivariate-adjusted continuous analyses, both CBP and ABP predicted cardiovascular, cerebrovascular, cardiac and coronary events. However, in fully-adjusted models, including both CBP and ABP, CBP lost its predictive value (P >or= 0.052), whereas systolic and diastolic ABP retained their prognostic significance (P or= 0.21). In adjusted categorical analyses, normotension was the referent group (CBP < 140/90 mmHg and ABP < 135/85 mmHg). Adjusted hazard ratios for all cardiovascular events were 1.22 [95% confidence interval (CI) = 0.96-1.53; P = 0.09] for white-coat hypertension (>or= 140/90 and < 135/85 mmHg); 1.62 (95% CI = 1.35-1.96; P < 0.0001) for masked hypertension (< 140/90 and >or= 135/85 mmHg); and 1.80 (95% CI = 1.59-2.03; P < 0.0001) for sustained hypertension (>or= 140/90 and >or= 135/85 mmHg). CONCLUSIONS: ABP is superior to CBP in predicting cardiovascular events, but not total and noncardiovascular mortality. Cardiovascular risk gradually increases from normotension over white-coat and masked hypertension to sustained hypertension.     

Normal ambulatory blood pressure: a clinical practice-based comparison of two recently published definitions

The European Society of Hypertension (ESH) has issued guidelines for the detection and treatment of hypertension. According to these guidelines, normal 24-h ambulatory blood pressure (ABP) is defined as lower than 125/80 mmHg. Another publication of ESH recommendations for blood pressure (BP) measurement defines normal awake and asleep blood pressure as lower than 135/85 and 120/70 mmHg, respectively. Our aim was to investigate the compatibility of these two recently proposed ABP cutoffs in clinical practice. We analysed 1495 consecutive ABP measurements. In all, 56% of the subjects were female; age 58 +/- 16 years; body mass index 27 +/- 4 kg/m(2); clinic BP 151+/-22/84 +/- 13 mmHg. Two-thirds were treated for hypertension, and 11% for diabetes. Subjects were classified as having normal 24-h BP if the corresponding value was <125/80 mmHg. Normal awake-sleep BP was diagnosed if awake BP was <135/85 mmHg and sleep BP was <120/70 mmHg. Concordance between the cutoffs was found in 93% of the subjects. Among the 7% discordant subjects, 4.5% were hypertensive applying the 24 h, but not awake-sleep, BP values, whereas only 2.5% were hypertensive according to awake-sleep, but not 24 h, BP values (P < 0.005). In Conclusion, in real-life ABP measurement, a good agreement was found between two recently issued ABP normality definitions. However, some subjects are classified as hypertensive only according to one of these methods, more often by the 24-h cutoff of 125/80. This discordance may be significant in large-scale clinical BP monitoring.     

高血压患者左室肥厚及主动脉根内径与动态血压的关系

目的探讨ＡＢＰ与左室后壁厚度（ＬＶＰＷＴ），室间膈厚度（ＩＶＳＴ）及主动脉内径（ＡＯＤ）之间的联系。方法对８８例原发性高血压患者应用超声心动图及动态血压计同时测定其ＬＶＰＷＴ、ＩＶＳＴ、ＡＯＤ及动态血压各参数值。结果左室肥厚（ＬＶＰＷＴ或／和ＩＶＳ）者５０例，主动脉根扩张者６０例。相关分析显示ＬＶＰＷＴ、ＬＶＳＴ及ＡＯＤ、动态血压各参数平均值呈显著正相关（Ｐ＜０．０５），其中与２４ｈ平均收缩压、最高收缩压及夜间平均收缩压相关最密切（Ｐ＜０．０１），此外ＬＶＰＷＴ，ＩＶＳＴ及ＡＯＤ与２４ｈ最高收缩压与最低收缩压之差（ΔＡＢＰｓ）及２４ｈ最高舒张压与最低舒张压之差（ΔＡＢＰｓ）亦呈正相关（Ｐ＜０．０５），其中与ΔＡＢＰｓ相比更密切（Ｐ＜０．０１）。结论血压波动性是左室肥厚及主动脉根内径的影响因素。     

Blood Pressure Monitoring. Task force III: Target-organ damage, morbidity and mortality

OBJECTIVE: To reach a consensus on ambulatory blood pressure (ABP) as a predictor of target-organ damage (TOD), morbidity and mortality. METHOD:The 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 CONSENSUS: In 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 (24h 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 24h. 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. (ABST     

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.     

Task Force II: blood pressure measurement and cardiovascular outcome

OBJECTIVE: To reach a consensus on the prognostic significance of new techniques of automated blood pressure measurement. METHODS: A Task Force on the prognostic significance of ambulatory blood pressure monitoring wrote this review in preparation for the Eighth International Consensus Conference (28-31 October 2001, Sendai, Japan). This synopsis was amended to account for opinions aired at the conference and to reflect the common ground reached in the discussions. POINTS OF CONSENSUS: (1) Prospective studies in treated and untreated hypertensive patients and in the general population have demonstrated that, even after adjusting for established risk factors, the incidence of cardiovascular events is correlated with blood pressure on conventional as well as ambulatory measurement. Ambulatory monitoring, however, significantly refines the prediction already provided by conventional blood pressure measurement. (2) White-coat hypertension is usually defined as an elevated clinic blood pressure in the presence of a normal daytime ambulatory blood pressure. Event-based studies in hypertensive patients have convincingly demonstrated that the risk of cardiovascular disease is less in patients with white-coat hypertension than in those with higher ambulatory blood pressure levels even after controlling for concomitant risk factors. Based on prognostic evidence, white-coat hypertension can now be defined as a conventional blood pressure that is persistently equal to or greater than 140/90 mmHg with an average daytime ambulatory blood pressure of below 135/85 mmHg. The issue of whether or not white-coat hypertension predisposes to sustained hypertension needs further research. (3) There is a growing body of evidence showing that a decreased nocturnal fall in blood pressure (<10% of the daytime level) is associated with a worse prognosis, irrespective of whether night-time dipping is studied as a continuous or a class variable. (4) Intermittent techniques of ambulatory blood pressure monitoring are limited in terms of quantifying short-term blood pressure variability. Proven cardiovascular risk factors such as old age, a higher than usual blood pressure and diabetes mellitus are often associated with greater short-term blood pressure variability. After adjusting for these risk factors, some - but not all - studies have nevertheless reported an independent and positive relationship between cardiovascular outcome and measures of variability of daytime and night-time blood pressure, for example standard deviation. (5) Reference values for ambulatory blood pressure measurement in children are currently based on statistical parameters of blood pressure distribution. In children and adolescents, functional rather than distribution-based definitions of ambulatory hypertension have yet to be developed. (6) Several studies of gestational hypertension have shown that, compared with office measurement, ambulatory blood pressure monitoring is a better predictor of maternal and fetal complications. Pregnancy is a special indication for ambulatory monitoring so that the white-coat effect can be measured and pregnant women are not given antihypertensive drugs unnecessarily. (7) Ambulatory pulse pressure and the QKD interval are measurements obtained by ambulatory monitoring that to some extent reflect the functional characteristics of the large arteries. The QKD interval is correlated with left ventricular mass, and ambulatory pulse pressure is a strong predictor of cardiovascular outcome. (8) Under standardized conditions, the self-measurement of blood pressure is equally as effective as ambulatory blood pressure monitoring in identifying the white-coat effect, but further studies are required to elucidate fully the prognostic accuracy of self-measured blood pressure in comparison with conventional and ambulatory blood pressure measurement. CONCLUSIONS: Ambulatory blood pressure measurement refines the prognostic information provided by conventional blood pressure readings obtained in the clinic or the doctor's office. Longitudinal studies of patients with white-coat hypertension should clarify the transient, persistent or progressive nature of this condition, particularly in paediatric patients, in whom white-coat hypertension may be a harbinger of sustained hypertension and target-organ damage in adulthood. Finally, the applicability, cost-effectiveness and long-term prognostic accuracy of the self-measurement of blood pressure should be evaluated in relation to conventional blood pressure measurement and ambulatory monitoring.     

Target-organ damage and cardiovascular risk profile in resistant hypertension. Influence of the white-coat effect

BACKGROUND: It is difficult to draw definite conclusions about the prevalence and clinical characteristics of patients with resistant hypertension because of the heterogeneity of study designs described in published studies. OBJECTIVES: To estimate the prevalence of resistant hypertension, the associated cardiovascular risk factors and the degree of target-organ damage, and to analyze the differences between true resistant hypertension (TRH) and white-coat resistant hypertension (WCRH). DESIGN: Cross-sectional study. METHODS: Patients who visited the Hypertension Clinic with resistant hypertension were sequentially included. Resistant hypertension was defined as an average of three measurements of systolic blood pressure, >/= 160 mmHg or a diastolic blood pressure >/= 95 mmHg, or both, in patients treated with a triple-drug regimen, over at least 2 months. Twenty-four-hour ambulatory blood pressure monitoring and M-mode bi-dimensional echocardiography were performed. WCRH was defined as a mean daytime ambulatory blood pressure 相似文献   

Ambulatory monitoring predicts development of drug-treated hypertension in subjects with high normal blood pressure

BACKGROUND: High normal blood pressure (HNBP), i.e. blood pressure (BP) > or = 130/85 mmHg and <140/90 mmHg, is an important predictor of progression to established hypertension. DESIGN: The purpose of this retrospective study was the evaluation of the predictive value of ambulatory blood pressure monitoring (ABPM) for the development of drug-treated hypertension in subjects with HNBP and other risk factors. METHODS: We studied 127 subjects (69 M, 58 F, age 50 +/- 14 years): 59 subjects had normal BP (NBP: < 130/85 mmHg), 68 subjects had systolic and/or diastolic HNBP. All the subjects underwent ABPM. There were 21/68 (30.9%) subjects in the HNBP group vs. 1/59 (1.7%) in the NBP group with an elevated (>135/85 mmHg) daytime ambulatory blood pressure (ABP) (p < 0.01). RESULTS: After an average follow-up of 103 +/- 28 months, 27 subjects (39.7%) in the HNBP group and 4 subjects (6.8%) in the NBP group developed drug-treated hypertension (p < 0.01). An elevated daytime ABP correctly predicted development of drug-treated hypertension in 17/21 subjects (81%) of the HNBP group and in the only subject of the NBP group. Development of drug-treated hypertension was associated with higher office and ambulatory BP (p < 0.01) and pulse pressures (p < 0.05), longer follow-up (p < 0.05) and higher prevalence of hypercholesterolaemia and smoking (p < 0.01). CONCLUSIONS: We conclude that ABPM correctly predicts development of drug-treated hypertension in most subjects who were identified early as having a daytime mean ABP >135/85 mmHg. ABPM appears to be a useful clinical tool in the early diagnosis of hypertension in subjects with metabolic risk factors and smoking.     

Relationship between joint national committee-VI classification of hypertension and ambulatory blood pressure in patients with hypertension diagnosed by casual blood pressure

Background: White-coat hypertension has been diagnosed arbitrarily based on different criteria. In 1997, the Joint National Committee-VI (JNC-VI) reported a new classification of hypertension and strongly emphasized the importance of ambulatory blood pressure (ABP) monitoring. The report pronounced normal ABP values for the first time. Hypothesis: The study's aim was to clarify the relationship between casual blood pressure (BP) and ABP of patients with essential hypertension in each stage of JNC-VI classification, and the prevalence of white-coat hypertension diagnosed by using JNC-VI normal ABP criteria. Methods: Ambulatory blood pressure was monitored noninvasively in 232 patients with essential hypertension whose casual BP was ≥ 140/90 mmHg. The patients were classified according to JNC-VI classification, and their casual BP was compared with ABP. The criterion of white-coat hypertension was defined as casual BP ≥ 140/90 mmHg with normal ABP according to JNC-VI criteria (< 135/85 during daytime and < 120/75 during nighttime). Results: Mean ABP increased as the stage advanced, and the differences between casual BP and ABP also increased. There were considerable overlaps in the distribution of ABP among stages. The prevalence of white-coat hypertension was 13% overall: 30% of the patients with isolated systolic hypertension, 19% of those in stage 1,10% in stage 2, and 4% in stage 3. Conclusions: Classification of hypertension based on casual BP may not always correspond in severity to that based on ABP. Ambulatory blood pressure monitoring recommended by JNC-VI is very useful for the evaluation of hypertension to differentiate white-coat hypertension from true hypertension.     

Classification of blood pressure levels by ambulatory blood pressure in hypertension

Whereas clinic blood pressure (CBP) above normality is divided into stages, no corresponding classifications are available for 24-hour ambulatory blood pressure (ABP). We conducted a study (1) to define stages of hypertension by ABP corresponding to CBP stages and (2) to evaluate if these stages have prognostic impact similar to CBP stages. Seven hundred thirty-six hypertensive patients were included. Mean systolic blood pressure was 149+/-15.2/87+/-8.6 mm Hg for CBP and 135+/-13/79+/-9.7 mm Hg for ABP. The mean bias between both methods was -13.3 mm Hg (95% CI, -14.3 to -12.2; 1.96xSD limits of agreement, 15.7 to -42.3) and -7.3 mm Hg (95% CI, -7.9 to -6.6; 1.96xSD limits of agreement, 9.8 to -24.3) for systolic and diastolic blood pressure (P>0.0001 for both), respectively. Classification of hypertension by ABP revealed lower cutoff values for the different stages of hypertension compared with the corresponding cutoff values for CBP (CBP versus ABP: 140/90 versus 132/81 mm Hg; 160/100 versus 140/88 mm Hg; 180/110 versus 148/94 mm Hg, P<0.001). Overall, 82 (11.1%) patients had nonfatal clinical cardiovascular events and 9 (1.2%) patients died of a cardiovascular cause during follow-up. The distribution of cardiovascular events was significantly associated with increasing ABP value (P<0.006). Staging of hypertension by ABP may facilitate the use of this method in daily clinical practice, as ABP can now be used not only to confirm the diagnosis of hypertension but also to assess the severity and prognosis of hypertensive disease.     

The clinical significance of white-coat and masked hypertension

OBJECTIVE: Self-measured blood pressure (BP) and 24-hour ambulatory blood pressure (ABP) monitoring are used to define the arbitrary clinical categories of masked hypertension (MH) and white-coat hypertension (WCH). Severity of target organ damage and incidence of major cardiovascular events are greater in patients with MH than in patients whose BP is normal both inside and outside the doctor's office. METHODS: We reviewed studies that addressed the prognostic impact of MH and WCH. RESULTS: Overall, WCH was associated with a better outcome and MH to a poor outcome. We, however, need the criteria to identify the clinically normotensive patients at elevated pretest probability of MH in whom a broad use of self-measured home BP and 24-hour ambulatory BP as screening tests may be appropriate and cost effective. Clinical management of patients with MH should continue to be based on current guidelines and mostly related to target organ damage and associated clinical conditions because of the normal values of clinic BP in these patients. WCH is generally defined by the coexistence of persistently high office BP with normal daytime or 24-hour ABP. Daytime ABP normalcy has been defined by values<135/85 mmHg. Data, however, suggest that incidence of cardiovascular events tends to increase consistently above the cut-off value of 130/80 mmHg for daytime BP. CONCLUSION: The long-term outcome of patients with WCH remains uncertain. Data suggesting an increased risk of stroke need to be confirmed in wide-scale studies.     

Home blood pressure self-monitoring: diagnostic performance in white-coat hypertension

OBJECTIVE: To determine the diagnostic performance of home blood pressure self-monitoring in white-coat hypertension using a 3-day reading program. MATERIAL AND METHODS: One hundred and ninety nontreated patients recently diagnosed with mild-moderate hypertension, selected consecutively at four primary healthcare centers in the city of Barcelona, were included. Each patient underwent morning and night home blood pressure self-monitoring with readings in triplicate for three consecutive days, followed by 24-h ambulatory blood pressure monitoring. The normality cut-off point value for home blood pressure self-monitoring and daytime ambulatory blood pressure monitoring was 135/85 mmHg. RESULTS: Sixty-three patients were diagnosed with white-coat hypertension with home blood pressure self-monitoring (34.8%; 95% confidence interval: 27.9-42.2) and 74 with ambulatory blood pressure monitoring (41.6%; 95% confidence interval: 33.7-48.4). No statistically significant differences were observed between home blood pressure self-monitoring values and those of diurnal ambulatory blood pressure monitoring [137.4 (14.3)/82.1 (8.3) mmHg vs. 134.8 (11.3)/81.3 (9.5) mmHg]. Home blood pressure self-monitoring diagnostic performance parameters were sensitivity 50.0% (95% confidence interval: 38.3-61.7), specificity 75.7% (95% confidence interval: 66.3-83.2), positive and negative predictive values 58.7% (95% confidence interval: 45.6-70.8) and 68.6% (95% confidence interval: 59.4-76.7), respectively, and positive and negative probability coefficients 2.05 and 0.66, respectively. Analysis of different normality cut-off points using a receiver operating characteristic curve failed to produce significant improvement in the diagnostic performance of home blood pressure self-monitoring. CONCLUSIONS: The diagnostic accuracy of a 3-day home blood pressure self-monitoring reading program in white-coat hypertension was poor. Ambulatory blood pressure monitoring continues to be the test of choice for this indication.