Conventional and ambulatory measurements of blood pressure in old patients with isolated systolic hypertension: baseline observations in the Syst-Eur trial

OBJECTIVES: To compare clinic and am measurements of blood pressure in old patients with isolated systolic hypertension and their reproducibilities. PATIENTS: In total 610 patients aged >/= 60 years with isolated systolic hypertension detected by clinic measurement were monitored during the placebo run-in phase of the Syst-Eur trial. METHODS: The time-weighted 24 h blood pressure, clock-time day and night blood pressures, the cumulative-sum-derived crest and trough blood pressures and the high and low blood pressure levels according to the square-wave model were computed. The daily alteration between the high and low spans of blood pressure was quantified using the day-night difference, the cumulative-sum-derived magnitude of circadian alteration, the Fourier amplitude and the difference between the high and low blood pressure levels of the square-wave model. RESULTS: The daytime am systolic blood pressure was, on average, 21 mmHg lower than the clinic systolic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. Clinic levels of blood pressure in the 141 patients who underwent repeat measurements and the parameters describing the difference between the daily high and low spans of blood pressure were equally reproducible. However, both were less reproducible than the ambulatory blood pressure levels. The reproducibility coefficients, expressed as percentages of near maximum variation, were 49 and 50% for the clinic systolic and diastolic blood pressures, 30 and 32% for the mean 24 h systolic and diastolic blood pressures and 45-55% for the parameters describing the daily alteration between the high and low spans of blood pressure. CONCLUSION: Values of blood pressure in old patients with isolated systolic hypertension were more reproducible for ambulatory than they were for clinic measurements. Levels in patients selected because they have a high clinic blood pressure may be substantially higher with conventional than they are with daytime ambulatory measurement. The prognostic significance of this difference for the present patients is currently under investigation.     

Ambulatory blood pressure monitoring in elderly patients with isolated systolic hypertension.

OBJECTIVES: This study compared clinic and ambulatory blood pressure measurement and the reproducibility of these measurements in older patients with isolated systolic hypertension (ISH). PATIENTS: Eighty-seven patients aged greater than or equal to 60 years with ISH on clinic measurement were followed in the placebo run-in phase of the Syst-Eur trial. METHODS: Clinic blood pressure was defined as the mean of two blood pressure readings on each of three clinic visits (six readings in total). Ambulatory blood pressure was measured over 24 h using non-invasive ambulatory blood pressure monitors. RESULTS: Daytime ambulatory systolic pressure was, on average, 21 mmHg lower than the clinic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. In the 42 patients who had repeat measurements, clinic blood pressure levels nad the amplitude of the diurnal blood pressure profile (fitted by Fourier analysis) were equally reproducible. However, both were less reproducible than ambulatory blood pressure levels. The repeatability coefficients, expressed as per cent of near maximum variation (four times the standard deviation of a given measurement), were 52% and 45% for the clinic systolic and diastolic pressures, 56% and 42% for the amplitude of the diurnal profile, and 29% and 26% for mean 24-h pressures. CONCLUSIONS: In older patients with ISH, clinic and ambulatory systolic blood pressure measurements may differ largely: the prognostic significance of this difference remains to be elucidated. Furthermore, in these patients the level of pressure is more reproducible by daytime ambulatory blood pressure measurement than by clinic measurement.     

Metabolic syndrome score and ambulatory blood pressure in untreated essential hypertension

BACKGROUND: The relationship between metabolic syndrome components, as defined by the Adult Treatment Panel III report, and ambulatory blood pressure in hypertensive patients has not been investigated to date. OBJECTIVE: To explore the relation between metabolic syndrome components ambulatory blood pressure levels and blood pressure day/night variations in a large population of never-treated essential hypertensive patients. METHODS: This investigation included 519 patients with uncomplicated grade 1 and 2 hypertension (mean age 45+11 years) who were attending a hypertension hospital outpatient clinic. They underwent the following procedures: (1) repeated clinic blood pressure measurements; (2) blood sampling for routine chemistry examinations; and (3) ambulatory blood pressure monitoring over two 24-h periods within 4 weeks. Because, by selection, all participants fulfilled one of the Adult Treatment Panel III criteria, the additional four criteria, abdominal obesity, hypertriglyceridemia, low HDL cholesterol and high blood fasting glucose, were specifically searched for. Patients were stratified according to the absence (group I) or the presence of one (group II), two (group III), three or four (group IV) components of the metabolic syndrome. Nocturnal dipping was defined as a night-time reduction in average systolic and diastolic blood pressure >10% compared to average daytime values. Each participant was classified according to the consistency of the dipping or nondipping status in the first and second ambulatory blood pressure measurement periods as follows: reproducible dipper (DD: decrease in blood pressure >10% in both ambulatory blood pressure measurement periods), reproducible nondipper (ND-ND: decrease in blood pressure <10% in both ambulatory blood pressure measurement periods) and variable dipper (VD: i.e dipper in one and nondipper in the other ambulatory blood pressure measurement period). RESULTS: In the whole population mean clinic and 48-h ambulatory blood pressures were 146/96 and 136/87 mmHg, respectively. In all, 197 patients (38%) had no metabolic syndrome components other than high blood pressure, 171 (33%) had one, 109 (21%) had two and 42 (8%) had three or four components. The four groups did not differ in age, clinic blood pressure, average 48-h, daytime, night-time systolic and diastolic blood pressure, and percentages of nocturnal fall in systolic and diastolic blood pressure. Furthermore, the distribution of three different ambulatory blood pressure patterns (DD, ND-ND and VD) was similar in the four groups: I=54.6%, 23.0%, 22.4%; II=51.1%, 21.7%, 27.2%; III=51.9%, 23.6%, 24.5%; and IV=52.7%, 27.2%, 25.1%, respectively. CONCLUSIONS: Our findings indicate that no significant relationship exists between the extent of metabolic alterations and ambulatory blood pressure levels or circadian variations in blood pressure in uncomplicated essential hypertensive patients.     

Racial aspects of ambulatory blood pressure.

Ambulatory blood pressure measurements, recorded by a Del Mar Pressurometer IV, were performed in 71 patients (25 blacks and 46 whites) with documented essential hypertension (supine diastolic blood pressure 95-119 mmHg) after four weeks of placebo treatment. Each 24-hour ambulatory BP measurement was calibrated with manual measurements within 5 mmHg and was repeated according to the daily conditions (work status) of the original recording. Ambulatory BP measurements were recorded every 15 minutes over 24 hours on two separate occasions one week apart. The mean of two 24-hour measurements was the value for the individual patient. Analyses of variance indicated no significant difference in the mean age, height, weight, 24-hour ambulatory systolic or diastolic BP, 8 am to 12 noon systolic or diastolic ambulatory BP, or 12 midnight to 4 am ambulatory systolic or diastolic BP for blacks versus whites. Among the subset of females, the 20 blacks were older than the 23 whites. Despite this age difference, there was no significant difference in height, weight or 24-hour, 8 am to 12 noon, or 12 midnight to 4 am ambulatory BP measurements. Therefore, this study does not support a racial difference in the level of ambulatory blood pressure measurement in these hypertensive patients.     

Reproducibility of ambulatory blood pressure measurements in essential hypertension

BACKGROUND: Data on the reproducibility of serial measurements of ambulatory blood pressure in hypertensive patients are lacking. The purpose of this study was to examine (1) the reproducibility of four consecutive ambulatory blood pressure measurements, and (2) the reproducibility of nocturnal falls in blood pressure in hypertensive patients. METHODS: Twenty patients with mild to moderate essential hypertension underwent four separate ambulatory blood pressure monitorings, on the same day of the week, at 30-day intervals. Antihypertensive therapy was discontinued for 2 weeks before each recording. Comparing the mean values of blood pressure over 24h, as well as diurnal, nocturnal and hourly periods, among the four recordings determined the reproducibility of blood pressure measurements. A day/night difference in mean systolic and in mean diastolic blood pressure defined the nocturnal fall in blood pressure. RESULTS: No significant differences were observed in either hourly, 24-h, diurnal or nocturnal systolic blood pressure, diastolic blood pressure and heart rate, or in the nocturnal fall in systolic and diastolic blood pressure among the four recordings. CONCLUSIONS: Hourly systolic blood pressure, diastolic blood pressure, heart rate, and nocturnal fall in blood pressure were reproducible in four ambulatory blood pressure monitorings recorded over 4 months. These findings suggest that ambulatory blood pressure monitoring is a reliable tool to monitor blood pressure changes.     

Home blood pressure in poorly controlled hypertension: relationship with ambulatory blood pressure and organ damage

OBJECTIVES: (1) To assess whether home blood pressure measurement is a reliable alternative to ambulatory blood pressure monitoring for the evaluation of treated patients with inadequate blood pressure control at the clinic; and (2) to evaluate the relationship between home blood pressure and several target-organ damage markers. BASIC METHODS: A cross-sectional study was performed in 225 treated hypertensive patients with persistently high blood pressure values at the clinic (systolic blood pressure 140 mmHg and/or diastolic blood pressure 90 mmHg). All study participants underwent clinic blood pressure measurement, 24-h ambulatory blood pressure and home blood pressure monitoring. A subgroup of patients underwent the following procedures: carotid echography (n=74), microalbuminuria determination (n=88) and echocardiography (n=43). We defined out-of-clinic normotension as an average ambulatory or home blood pressure less than 135 mmHg (systolic) and 85 mmHg (diastolic). MAIN RESULTS: The sensitivity, specificity and positive and negative predictive values of the home blood pressure method for predicting out-of-clinic normotension (with the ambulatory method used as reference), expressed as percentages, were 50, 87, 64 and 79%, respectively. Systolic home blood pressure correlated significantly with left ventricular mass (r=0.33, P<0.05) and microalbuminuria (r=0.24, P<0.05). Similar correlation coefficients were found for systolic ambulatory blood pressure (r=0.32, P<0.05 and r=0.24, P<0.05, respectively). Clinic blood pressure did not correlate with either left ventricular mass or microalbuminuria (r=0.19, P=0.09 and r=0.19, P=0.24, respectively). Diastolic home blood pressure, but not ambulatory blood pressure, correlated negatively with mean carotid intima-media thickness (r=-0.27, P<0.05). CONCLUSION: Our results suggest that, in patients with poorly controlled hypertension at the clinic, home blood pressure represents a complementary test rather than an alternative to ambulatory blood pressure, and correlates with several target-organ damage markers.     

The influence of ambulatory blood pressure monitoring on the design and interpretation of trials in hypertension.

OBJECTIVE: To describe the reproducibility of diastolic blood pressure (DBP) measurement by clinic and ambulatory monitoring and to evaluate the effects of this reproducibility on the design and interpretation of clinical trials in hypertension research. DESIGN: Prospective single-blind study of repeat measurement reproducibility of blood pressure recording. SETTING: Tertiary referral hospital hypertension clinic. PATIENTS: One hundred untreated mild-to-moderate hypertensive subjects taking 1 month of single-blind placebo. MAIN OUTCOME MEASURES: A single clinic measurement of DBP was poorly reproducible and the results for single DBP estimates taken out of a daytime ambulatory recording were similar. Average ambulatory DBP was much more reproducible, although this improvement depended upon the averaging of many measurements taken throughout the day. CONCLUSIONS: Ambulatory monitoring would decrease antihypertensive trial size by a factor of four or halve the size of detectable DBP difference between treatments. The use of poorly reproducible DBP measurements such as single clinic readings may have led to an underestimation of the risks of minor degrees of blood pressure elevation because of a 'regression dilution' bias. For single clinic DBP readings, we calculate this underestimation to be as much as 69%, and for average ambulatory DBP approximately 20%.     

Blood pressure response to antihypertensive therapy: ambulatory versus office blood pressure readings

Blood pressure readings obtained by the physician in his office and ambulatory blood pressures recorded with the semi-automatic Remler device, were compared during a controlled antihypertensive drug trial. Either timolol or methyldopa was administered in in double-blind fashion to 30 patients with uncomplicated essential hypertension. All exhibited a diastolic office blood pressure greater than 95 mmHg at the end of a four-week placebo period. All patients then received a combination of hydrochlorothiazide (25 mg/day) and amiloride (2.5 mg/day). After four weeks of diuretic therapy, timolol (10 mg/day, n = 14) or methyldopa (250 mg/day, n = 16) were added randomly for six weeks. The dose of all antihypertensive agents was doubled after two weeks of therapy with diuretics combined with timolol (n = 7) or methyldopa (n = 16) because of the persistence of diastolic blood pressure levels greater than 90 mmHg at the office. When assessed in the office, the antihypertensive effect of timolol and methyldopa was similar. During ambulatory blood pressure monitoring, however, pressure levels were lower in the patients given timolol (P less than 0.05 for the diastolic). With both regimens, the blood pressure response measured outside the clinic during usual daily activities could not be predicted from that observed with office blood pressure readings. Furthermore the magnitude of the drug induced blood pressure decrease was more reproducible in time when determined outside the clinic. These data suggest that ambulatory blood pressure monitoring is more precise in evaluating the efficacy of antihypertensive therapy than office blood pressure measurement.     

Reproducibility of nurse-measured, exercise and ambulatory blood pressure and echocardiographic left ventricular mass in borderline hypertension.

OBJECTIVE: To compare the short-term reproducibility of four diagnostic tests: resting blood pressure, exercise blood pressure, non-invasive daytime ambulatory blood pressure and echocardiographic left ventricular mass. DESIGN: Blinded, prospective test-retest (reliability) study. SETTING: Hypertension research units in two teaching hospitals. PARTICIPANTS: Six normal volunteers and 22 patients with untreated borderline to mild hypertension, mean age 44 years. MAIN OUTCOME MEASURES: The intraclass correlation coefficient (RI) and standard deviation of the difference (SDD) between visits. MAIN RESULTS: The mean blood pressures and left ventricular mass did not differ between visits. Concordance between visits reached RI = 0.86 systolic/0.66 diastolic for ambulatory blood pressure and RI = 0.85 systolic/0.64 diastolic for nurse-measured random-zero sphygmomanometer resting blood pressure. The respective variabilities were SDD = 9/8 and 8/8 mmHg. Submaximal exercise systolic blood pressure (SBP) and echo left ventricular mass showed excellent reliability. Echo left ventricular mass and resting SBP or ambulatory SBP were significantly more reproducible than resting diastolic blood pressure (DBP) or ambulatory DBP. CONCLUSIONS: Despite averaging many readings within each day, clinically important between-visit variations in ambulatory blood pressure remained. The between-visit variability of daytime ambulatory blood pressure was similar to that of resting blood pressure when carefully measured by a research nurse. The echo left ventricular mass appears to be more reproducible over the short term than the current diagnostic standard for hypertension, the resting DBP.     

Potassium supplementation reduces clinic and ambulatory blood pressure in elderly hypertensive patients.

OBJECTIVES: To determine the effects of potassium chloride 60 mmol/day supplementation on clinic and 24-h ambulatory blood pressure values in elderly untreated hypertensive patients. DESIGN: A double-blind randomized placebo-controlled crossover study lasting 8 weeks, following a 4-week run-in period. SETTING: Outpatient clinic in a district general hospital. PATIENTS: Eighteen untreated elderly hypertensive patients (mean age 75 years, range 66-79) with a systolic blood pressure of > or = 160 mmHg and/or a diastolic blood pressure of > or = 95 mmHg were recruited from the clinics of local general practitioners and from the current hospital outpatient department. Patients had not received any antihypertensive medication for at least 4 weeks before entry into the study. INTERVENTIONS: Before entry into the study, the daily dietary electrolyte intake of each individual was established and this was maintained during the run-in and intervention periods. Following a 4-week run-in period patients received potassium supplements or matching placebo, each for 4 weeks. MAIN OUTCOME MEASURES: The within-patient changes in clinic and 24-h ambulatory blood pressures at the end of each intervention period. RESULTS: After 4 weeks potassium supplementation compared with placebo there was a significant fall in supine clinic blood pressure, standing and 24-h ambulatory systolic blood pressure. There was no significant change in clinic standing diastolic blood pressure, 24-h ambulatory diastolic blood pressure or pulse rate. Plasma renin activity increased and body weight fell after potassium supplementation. Twenty-four-hour urinary potassium rose significantly, whereas urinary sodium excretion was unchanged. CONCLUSIONS: A 60-mmol daily supplement of potassium chloride reduces clinic and 24-h ambulatory blood pressure in elderly hypertensive patients.     

Loaned self-measurement equipment model compared with ambulatory blood pressure monitoring

OBJECTIVE: To compare the correspondence between the loaned self-measurement equipment model (LSEM), 24 h awake ambulatory blood pressure monitoring (ABPM) and clinic blood pressure (CBP). DESIGN: A cross-sectional study was carried out involving 90 hypertensive and normotensive subjects. METHODS: We used a variation of home measurement, the loaned self-measurement equipment model (LSEM), that consisted of lending a number of sphygmomanometers, the property of the clinic, to patients for 3-day periods. The correspondence of results from LSEM was measured against the difference between the two averages, the correlation coefficients and the average unweighted absolute differences. RESULTS: The average difference between CBP and ABPM was 6.1/2.5 mmHg (P<0.001, r =0.54/0.63). Between CBP and LSEM, it was 6.6/1.4 mmHg (P<0.001/ 0.08, r =0.52/0.63), and between the ABPM and LSEM 0.5/-1.0 mmHg (P=0.70/0.14, r =0.71/0.75). The average unweighted absolute differences between LSEM and ABPM readings were 5.5 and 1.5 mmHg for systolic and diastolic blood pressure, respectively, whereas the average difference between CBP and ABPM means was much higher, at 6.8 mmHg for systolic and 2.7 mmHg for diastolic pressure. Agreement in the diagnosis of systolic hypertension between LSEM and ABPM was found in 78.8% of the individuals, and of diastolic hypertension in 76.7%. CONCLUSION: Blood pressure readings taken using LSEM have a better correspondence than CBP in predicting the awake ABPM value, although the disagreement in terms of diagnosing hypertension should be noted.     

Superiority of ambulatory over clinic blood pressure measurement in predicting mortality: the Dublin outcome study

The purpose of this study was to determine if ambulatory blood pressure measurement predicted total and cardiovascular mortality over and beyond clinic blood pressure measurement and other cardiovascular risk factors; 5292 untreated hypertensive patients referred to a single blood pressure clinic who had clinic and ambulatory blood pressure measurement at baseline were followed up in a prospective study of mortality outcome. Multiple Cox regression was used to model time to total and cause-specific mortality for ambulatory blood pressure measurement while adjusting for clinic blood pressure measurement and other risk factors at baseline. There were 646 deaths (of which 389 were cardiovascular) during a median follow-up period of 8.4 years. With adjustment for gender, age, risk indices, and clinic blood pressure, higher mean values of ambulatory blood pressure were independent predictors for cardiovascular mortality. The relative hazard ratio for each 10-mm Hg increase in systolic blood pressure was 1.12 (1.06 to 1.18; P<0.001) for daytime and 1.21 (1.15 to 1.27; P<0.001) for nighttime systolic blood pressure. The hazard ratios for each 5-mm Hg increase in diastolic blood pressure were 1.02 (0.99 to 1.07; P=NS) for daytime and 1.09 (1.04 to 1.13; P<0.01) for nighttime diastolic pressures. The hazard ratios for nighttime ambulatory blood pressure remained significant after adjustment for daytime ambulatory blood pressure. These results have 2 important clinical messages: ambulatory measurement of blood pressure is superior to clinic measurement in predicting cardiovascular mortality, and nighttime blood pressure is the most potent predictor of outcome.     

Impact of obesity on 24-hour ambulatory blood pressure and hypertension

The purpose of the present study was to determine the relationship between body mass index (BMI) and parameters derived from 24-hour ambulatory blood pressure monitoring including mean 24-hour daytime and nighttime systolic and diastolic blood pressures, 24-hour daytime and nighttime pulse pressure, mean 24-hour daytime and nighttime heart rate, dipping and nondipping status. 3216 outpatient subjects who visited our hypertension center and were never treated with antihypertensive medication underwent 24-hour blood pressure monitoring. BMI was significantly correlated with clinic systolic and diastolic blood pressures. Significant correlations were also found between BMI and mean 24-hour daytime and nighttime systolic blood pressure, 24-hour daytime and nighttime pulse pressure, and mean 24-hour daytime and nighttime heart rate. In multivariate regression analysis, clinic systolic, diastolic blood pressure, mean 24-hour systolic blood pressure, 24-hour pulse pressure, and high-density lipoprotein were independently correlated with BMI. The incidence of white coat hypertension was higher in overweight and obese patients than in normal weight subjects. Confirmed ambulatory blood pressure hypertension was also found to be higher in overweight and obese individuals compared with normal weight subjects. Our data also highlight the higher incidence of nondipping status in obesity. These findings suggest that obese patients had increased ambulatory blood pressure parameters and altered circadian blood pressure rhythm with increased prevalence of nondipping status.     

Association of clinic and ambulatory blood pressure with vascular damage in the elderly: the EPICARDIAN study

OBJECTIVES: In middle-aged adults, vascular damage correlates better with ambulatory than with clinic blood pressure. This study aimed to determine whether vascular damage evaluated by carotid ultrasonography in the elderly is also more closely related to ambulatory than to clinic blood pressure, and which blood pressure variables are better associated with vascular damage. METHODS: Cross-sectional study of 292 randomly selected >65 years old participants who underwent 24-h noninvasive ambulatory blood pressure monitoring. Blood pressure variables analyzed were (a) clinic blood pressure: systolic and diastolic blood pressure, pulse pressure; (b) ambulatory blood pressure monitoring: mean values of systolic and diastolic blood pressure, systolic and diastolic blood pressure load, pulse pressure, as well as variability, evaluated within 24 h, diurnal and nocturnal periods; and day-night blood pressure difference. A clinical history, physical examination, carotid ultrasonography and laboratory tests were performed. To estimate the relationship between blood pressure and vascular damage, univariate and multivariate analyses were performed. RESULTS: Mean age: 73+/-6 years, 45% men, 76.7% hypertensive patients. In the simple regression analysis, the best significant correlations (P<0.05) were common carotid intima-media thickness with 24-h and nocturnal pulse pressure (r=0.32), and common carotid diameter with 24-h systolic blood pressure load (r=0.47). In the multivariate analysis, the significant associations (P<0.05) were (a) linear regression: nocturnal pulse pressure with common carotid intima-media thickness, and diurnal pulse pressure as well as 24-h systolic blood pressure load with common carotid diameter; (b) logistic regression, adjusted odds ratio: nocturnal pulse pressure and nocturnal diastolic blood pressure load with the presence of carotid atherosclerotic plaques 1.03 and 0.98, respectively. CONCLUSIONS: In the elderly, ambulatory blood pressure monitoring is better associated with carotid damage than clinic blood pressure. Systolic blood pressure variables are the best associated, blood pressure load and pulse pressure being better associated with carotid damage than the mean levels of ambulatory blood pressure.     

The white-coat effect is associated with increased blood pressure reactivity to physical activity

OBJECTIVE: The aim of this study was to test the hypothesis that blood pressure (BP) reactivity to the stress of a clinic visit, the so-called white-coat effect, is associated with increased BP reactivity to physical activity. DESIGN: Patients referred to our clinic for assessment of hypertension prospectively underwent 24-h ambulatory BP monitoring and simultaneous actigraphy. METHODS: The difference between mean clinic BP and mean daytime ambulatory BP was considered to be a measure of the white-coat effect. Presence or absence of a white-coat effect (clinic-daytime difference > 0 mmHg) was added to a mixed model regression of BP on mean activity score for the 10-min interval preceding BP measurement. RESULTS: The group (n = 421) was heterogeneous in age, gender, mean 24-h BP and use of antihypertensive medications. A total of 259 patients had a systolic white-coat effect; for diastolic BP there were 264. Female patients exhibited a significantly larger white-coat effect. Coefficients for the regressions of both systolic and diastolic blood pressure on physical activity levels were significantly higher in those who had a white-coat effect. CONCLUSIONS: These data suggest increased BP reactivity to activity in those with a white-coat effect. Patients with a prominent white-coat effect may experience greater BP load during normal daily activities as a consequence of increased BP reactivity. In patients with white-coat hypertension, this may contribute to target-organ damage.     

动态血压监测评价高血压患者靶器官损害246例分析

目的探讨动态血压监测对评价高血压患者靶器官损害的价值。方法对246例高血压患者进行24h动态血压监测,其中单纯血压升高118例为原发性高血压组,伴靶器官损害128例为伴靶器官损害组,进行统计学分析。结果(1)伴靶器官损害组24h收缩压、白昼舒张压、夜间舒张压低于原发性高血压组(P<0.01);(2)靶器官损害数目累及3个器官组与累及1个器官组相比,24h平均收缩压、夜间平均舒张压、血压波动的昼夜节律异常和血压负荷参数,差异有统计学意义。结论血压波动的昼夜节律异常、24h平均收缩压、夜间平均舒张压和血压负荷越高,靶器官损害数目越多。     

Twenty-four-hour ambulatory blood pressure monitoring in atrial fibrillation

BACKGROUND: Due to large beat-to-beat blood pressure variation the use of 24-h ambulatory blood pressure monitoring in patients with atrial fibrillation has been questioned. METHODS: Repeatability and variability of 24-h ambulatory blood pressure (Accutraccer II or Diasys Integra), and daily blood pressure variation was examined in 42 patients aged 51-81 (median 73.5) years admitted for elective electrocardioversion of atrial fibrillation. RESULTS: Before cardioversion 24-h ambulatory systolic blood pressure was slightly lower and nocturnal blood pressure reduction was larger in the group of patients who achieved sinus rhythm than in the group who maintained atrial fibrillation (11.5/10.5 versus 4.1/4.7 mmHg; P < 0.05). No statistically significant change was observed in ambulatory blood pressure after cardioversion in any of the two groups. Blood pressure variability (SD/mean) was 10-14% both in patients with and without conversion to sinus rhythm. Coefficient of repeatability (2 SD of difference) was 13.6 mmHg (16.6%) for diastolic blood pressure and 30.2 mmHg (24.7%) for systolic blood pressure in patients with normalized heart rhythm and 17.0 and 29.0 mmHg (21.5 and 22.4%) in patients with maintained atrial fibrillation, respectively. CONCLUSION: Ambulatory blood pressure monitoring provides data with similar variability and repeatability in patients with atrial fibrillation as in subjects with normal cardiac rhythm. Twenty-four-hour ambulatory blood pressure measurement is applicable in atrial fibrillation in the same way as during sinus rhythm.     

Analysis of blood pressure in children and adolescents reporting siesta during ambulatory blood pressure monitoring

BACKGROUND: In adults, a siesta yields a blood pressure profile similar to that seen in nocturnal sleep. It is therefore stressed that siestas should not be included in daytime blood pressure measurement. OBJECTIVES: To evaluate blood pressure profiles in pediatric and adolescent patients who reported a siesta during 24 h ambulatory blood pressure monitoring (ABPM). METHODS: Patients' diaries of actual sleep times were used to determine the periods of sleep (night-time and siesta) and daytime wakefulness. Ambulatory systolic and/or diastolic daytime and/or night-time hypertension was determined by comparing patients' measurements with normal values taken from published standards for healthy children and adolescents. Data obtained from 12 patients with ambulatory normotension and 12 patients with ambulatory hypertension, who were referred for an evaluation of hypertension or management of known hypertension, were analysed separately. RESULTS: Mean systolic (SBP) and diastolic (DBP) blood pressure values during the daytime awake period were significantly higher than the mean values for the period of daytime, including the siesta, both in patients with ambulatory normotension and in those with ambulatory hypertension (P<0.001 and P<0.01 for SBP and DBP, and P<0.001 and P<0.001 for SBP and DBP, respectively). The percentage night-time falls in SBP and DBP were 12.9+/-0.5 and 19.1+/-1.4 in patients with ambulatory normotension, and 7.1+/-1.5 and 12.9+/-2.2 in patients with ambulatory hypertension. These values were significantly higher when the siesta was excluded from the analysis in both groups (13.9+/-0.5% and 20.7+/-1.5%, P<0.001 and P<0.01 for SBP and DBP in patients with ambulatory normotension; 8+/-1.6% and 14.8+/-2.4%, P<0.001 and P<0.001 for SBP and DBP in patients with ambulatory hypertension, respectively). CONCLUSIONS: By ignoring the effect of the siesta, both the calculation of daytime blood pressure values and the analysis of day-night variability in children and adolescents undergoing ABPM may be erroneously interpreted.     

Repeated measurements of non-invasive ambulatory blood pressure: distinction between reproducibility and the proper effect of placebo

OBJECTIVE: To determine whether non-invasive ambulatory blood pressure is more reproducible and less affected by the placebo treatment than are clinic blood pressure measurements. METHOD: Thirty-four essential hypertensive outpatients were randomly allocated after a 4-week preselection period in two groups in a cross-over study design. One group received placebo for 4 weeks while the other formed the control group (reproducibility), then the treatments were exchanged for another 4 weeks. Clinic and ambulatory blood pressures were measured at three different times for each patient, namely bnefore the random allocation to groups and at the end of each period, using a mercury sphygmomanometer and 24 h non-invasive ambulatory blood pressure monitoring. RESULTS: Administration of placebo was accompanied by a significant reduction in systolic and diastolic clinic blood pressures (by 3.4+/-13 and 3.6+/-8 mmHg, respectively), but not in 24 h, daytime and night-time blood pressures. Circadian hourly blood pressure and heart rate curves were virtually superimposable. In the 13 placebo responder patients selected on the basis of clinic blood pressure, placebo decreased the clinic blood pressure and also reduced systolic and diastolic ambulatory blood pressures, mainly during the day period (by 5.2+/-6.2 and 4.89+/-7.8 mmHg, respectively). This effect is specific and related to the placebo administration because repetition of the measurements without any treatment showed no significant difference. To characterize at baseline the placebo responder patients, comparison with the non-placebo responders showed lower baseline values of ambulatory systolic blood pressure recorded during 24 h daytime and night-time in the placebo responder group. CONCLUSION: The 24 h ambulatory blood pressure average is not affected by placebo in the present group of patients but that a placebo effect occurs mainly during the daytime in patients who decreased their clinic blood pressure under placebo (placebo responders); the placebo-induced reduction in blood pressure is related to a specific effect of placebo and is independent from any alerting reaction or reproducibility hypothesis. This study clearly indicates the necessity of including placebo and ambulatory blood pressure monitoring in the therapeutic and pharmacological trials of antihypertensive drugs.     

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.