24-hour ambulatory blood pressure monitoring

24-hour ambulatory blood pressure monitoring (ABPM) is the exact, fully automatic and noninvasive method for evaluation of the 24-hour hemodynamic profile of the subject by multiple and regular blood pressure and heart rate measurement. In comparison with causal blood pressure measurement, ABPM allows the definition of daytime and nighttime blood pressure averages, diurnal changes of blood pressure, localization of periods of the most frequent appearance of hypertensive values, specification of hypertensive load, percent time elevation and diagnosing of white coat phenomenon. The use of all mentioned findings leads to the improvement of blood pressure control in patients with resistant hypertension, polymorbidity, helps to analyze paroxysmal hypertension, verify diagnosis of the hypertension in patients with borderline or high normal blood pressure. The final profit is the reduction of the target organ damage and reduction of cardiovascular morbidity and mortality. Definite diagnosis of the white coat phenomenon markedly decreases consumption of the antihypertensive drugs. In addition, this method enables better evaluation of hypotensive syndromes and is very helpful in the investigation of physiology of blood pressure regulation, biorhythms and in pharmacodynamical studies of the new antihypertensives.     

Experience with noninvasive ambulatory 24-hour blood pressure recording in a community hospital.

In 40 subjects (23 treated with antihypertensive medication), 24-h ambulatory blood pressure was measured with an oscillometric blood pressure monitor (Spacelabs model 90202). We studied applicability in the out-patient department with regard to patient tolerance, correlation with mercury manometer measurements, 24-h blood pressure variability and the use in detecting "white-coat" hypertension. The measurements were tolerated quite well except for complaints of sleep disturbance and local irritation from the cuff. The average percentage of missed measuring points was 9.2%. Correlation between blood pressure with the mercury manometer and the Spacelabs monitor (averages of three consecutive readings) was: systolic 0.87 and diastolic 0.73 (P less than 0.001). No evidence for systematic error between the two methods was found. Diurnal blood pressure variation was significant with an average night-time drop of 12 +/- 15 mmHg systolic and 12 +/- 11 mmHg diastolic. "Office" blood pressure measured with the Spacelabs monitor was in the hypertensive range for 28 patients (systolic greater than or equal to 160 and/or diastolic greater than or equal to 95 mmHg). Only 15 of these subjects still met the hypertension criteria on the basis of mean daytime ambulatory blood pressure values. When ambulatory blood pressures during arbitrary 3-h periods of the daytime were studied, the number of patients with established hypertension did not change. The patients with this "office" or "white-coat" hypertensive response could not be distinguished on the basis of variability in daytime blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Losartan versus atenolol on 24-hour ambulatory blood pressure. A LIFE substudy

Objective. The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study showed that losartan-based treatment reduced risk of the composite endpoint of cardiovascular death, stroke and myocardial infarction compared with atenolol-based treatment in patients with hypertension and left ventricular hypertrophy with similar office blood pressure (BP) reduction. Our aim was to investigate the effect of losartan- and atenolol-based treatment on 24-h ambulatory BP and heart rate (HR) in LIFE. Methods: In 110 patients, 24-h ambulatory BP and heart rate were recorded at baseline and 1 year after randomization. Results: Ambulatory BP was comparably reduced throughout the 24-h period after 1 year of losartan- vs atenolol-based antihypertensive treatment. Office and ambulatory BP were comparably reduced in the follow-up period. Early morning surge in BP was similar between groups. Non-dipping status was more frequent in the losartan group (p = 0.01). From baseline to Year 1 the 24-h HR profile for the losartan group was unchanged, but, as expected, there was a significant decrease in daytime HR in the atenolol group, which was not as large during early night-time. Conclusion: There were no differences in 24-h BP burden and HR that could explain the difference in outcome in favor of losartan vs atenolol in the LIFE study.     

Effects of continuous positive airway pressure versus supplemental oxygen on 24-hour ambulatory blood pressure

Obstructive sleep apnea (OSA) is associated with recurrent episodes of nocturnal hypoxia and increased risk for development of systemic hypertension. Prior studies have been limited, however, in their ability to show reduction in blood pressure after continuous positive airway pressure (CPAP) therapy, and the effect of supplemental oxygen alone on blood pressure in OSA has not been evaluated. We performed a randomized, double-blind, placebo-controlled study comparing the effects of 2 weeks of CPAP versus sham-CPAP versus supplemental nocturnal oxygen on 24-hour ambulatory blood pressure in 46 patients with moderate-severe OSA. We found that 2 weeks of CPAP therapy resulted in a significant reduction in daytime mean arterial and diastolic blood pressure and nighttime systolic, mean, and diastolic blood pressure (all Ps <0.05). Although nocturnal supplemental oxygen therapy improved oxyhemoglobin saturation, it did not affect blood pressure. We conclude that CPAP therapy reduces both daytime and nighttime blood pressure in patients with OSA, perhaps through mechanisms other than improvement of nocturnal oxyhemoglobin saturation.     

Once- and twice-daily bevantolol for systemic hypertension using 24-hour ambulatory intraarterial blood pressure recording

The antihypertensive efficacy of bevantolol, a selective beta 1-adrenoreceptor antagonist, was evaluated in 17 patients with essential hypertension, using continuous ambulatory intraarterial blood pressure (BP) monitoring. The study compared a twice-daily regimen (titrated dose of 200 to 600 mg/day) with the same amount given in a single daily dose. Within-patient comparisons of mean hourly systolic and diastolic BPs and heart rate showed a highly significant effect with twice-daily therapy (p less than 0.001) for all of the 24 hours. Similar significant results were obtained with a single morning dose. There was no difference between the pattern or extent of BP reduction with the 2 regimens. The decrease in BP after bevantolol persisted during the physiologic tests (rest, tilt, isometric and dynamic exercise). Four patients developed minor side effects with the single morning dose, and only 1 patient with the twice-daily regimen. These effects included tiredness, fatigue and dizziness. Unlike pure beta-blocking agents, bevantolol controlled the early morning increase in BP, lending support to the belief that it possesses vasodilatory properties in addition to beta blockade. These results suggest that bevantolol may be useful as first-line therapy in a once-daily dosage for the treatment of essential hypertension.     

血压正常高值者24小时动态血压分析

目的:探讨以偶测血压为诊断标准血压正常高值人群的24 h动态血压特点。方法:采用动态血压测定仪分别对理想血压组82例、血压正常高值组183例及高血压组127例受试者进行24 h动态血压检测(ABPM)。结果:24 h收缩压变异系数(24hSSD)理想血压组、血压正常高值组、高血压组分别为(14.0±2.1)%、(17.2±3.2)%和(20.5±4.6)%;24 h舒张压变异系数(24hDSD)3组分别为(10.4±1.9)%、(13.1±1.9)%和(16.3±2.1)%;非杓型血压所占比例分别为7%、25%、39%;收缩压负荷率(SBP-L)为(12±10)%、(35±20)%和(67±25)%;舒张压负荷率(DBP-L)为(12±9)%、(33±20)%和(62±25)%;血压正常高值组较理想血压组高、较高血压组低(分别P0.05,P0.01);收缩压夜间下降率(SBPF)分别为(17.4±4.3)%、(12.5±3.3)%和(9.2±3.6)%;舒张压夜间下降率为(DBPF)(16.1±3.7)%、(11.4±2.9)%和(9.1±3.3)%,较理想血压组低、较高血压组高(P0.01)。结论:正常高值人群较理想血压组血压平均水平升高,血压变异、血压负荷、非杓型血压比例增加,夜间血压下降率降低。     

24-hour blood pressure recording in patients with orthostatic hypotension

Continuous intra-arterial blood pressure measurement and electrocardiograms were obtained in two ambulatory patients with orthostatic hypotension due to autonomic dysfunction. Systolic and diastolic arterial pressure presented marked variations which took place mainly during the day and were related to several physical activities; however, marked falls in blood pressure were also observed during sleep and at the moment of arousal. A peak incidence of hypotensive events was found in the afternoon, mainly in the hours following the afternoon meal. Recording was repeated after 3 weeks of treatment with propranolol, 40 mg t.i.d. In patient 1, beta blockade drastically reduced the number and severity of hypotensive episodes, while propranolol failed to control blood pressure in patient 2, who experienced a higher number of hypotensive events during treatment. Findings of this study may be relevant to the management of patients with orthostatic hypotension and should contribute to a more accurate characterization of blood pressure profile in autonomic dysfunction.     

Experience with 24-hour ambulatory blood pressure monitoring in hypertension

Traditional sphygmomanometric blood pressure measurements may lead to errors in the diagnosis of arterial hypertension due to a number of factors, among which are the alerting reaction and pressor response induced in patients by the doctor's visit. This phenomenon, as quantified in our laboratory by continuous intraarterial recordings, is responsible for an average rise in systolic and diastolic blood pressure of 27/15 mm Hg, a rise that does not seem to be reduced by simply desensitizing the patient by means of more frequent physician visits. Twenty-four hour ambulatory blood pressure monitoring may theoretically improve the diagnostic approach to hypertensive patients by overcoming some limitations of isolated cuff measurements. In recording intraarterial blood pressure in 108 ambulant hypertensive subjects, we have found that 24-hour blood pressure values are able to discriminate among patients with different degrees of target organ damage better than isolated sphygmomanometric readings. Moreover, these studies have indicated that 24-hour blood pressure variability may be as important as blood pressure mean values in the assessment of cardiovascular complications. In clinical practice, however, intraarterial blood pressure monitoring is not feasible, and only noninvasive recorders can be used. Use of these devices does not induce any alerting reaction in the patients and does not interfere with day-night blood pressure changes. Although it is characterized by intermittent readings, this approach is not incompatible with a precise estimate of 24-hour blood pressure mean values.(ABSTRACT TRUNCATED AT 250 WORDS)     

24小时动态血压参数正常参照值的研究

目的　探讨国人２４ 小时动态血压（２４ ｈ ＡＢＰ）参数的正常参照值。方法　采用无创性携带式动态血压监测仪检测３００ 例，年龄２０～７９ 岁临床健康者的动态血压。结果　国人２４ 小时动态血压均值：（１１１－８／６８－２ ±８－５／６－１）ｍｍＨｇ（１ ｍｍＨｇ ＝ ０－１３３ ｋＰａ），白昼（１１３－９／７０－１ ±１０－４／６－９）ｍｍＨｇ；夜间（１０７－０／６５－３±９－０／６－０）ｍｍＨｇ。结论　推荐２４ 小时动态血压均值＜ １３０／８０ ｍｍＨｇ；白昼均值＜ １３５／８５ ｍｍＨｇ，夜间均值＜ １２５／７７ ｍｍＨｇ；夜间／白昼比值≤０－９０，即夜间血压下降率≥１０％ 可暂时作为动态血压参数的正常参照值。     

Underestimation of 24-hour hypotensive efficacy of nifedipine GITS versus enalapril: ambulatory recording as an adjunct to clinical blood pressure measurement

Aims: Short-acting calcium entry blockers should be used primarily in slow-release form. Furthermore, studies of the antihypertensive efficacy of drugs can be negatively influenced by between 15% and 30% of the enrolled patients not being hypertensive according to ambulatory blood pressure (BP) measurement. Thus, a randomized double-blind multicenter parallel-group study was conducted to compare the effect of nifedipine GITS (gastrointestinal therapeutic system) with enalapril. Methods and results     

24-hour ambulatory blood pressure monitoring in normal and hypertensive subjects

24-hour ambulatory blood pressures (BP) of 172 normal subjects and 167 hypertensive patients recorded by automatic ambulatory monitoring device (A method) and standard mercury sphygmomanometer (B method) were studied. The results show: (1) 66% of normal subjects and 78% hypertensive patients have an evident circadian rhythm BP during 24-hours, BP readings during sleep and noon time are lower. (2) There is no significant difference between times at work and at home readings (P greater than 0.05), but the mean BP during sleeping time is the lowest (P less than 0.01). (3) The correlative coefficient of 24-hour average BP and casual clinic BP is low (r = 0.38-0.74). (4) The validity and accuracy of ambulatory BP monitoring by A and B methods were compared.     

Verapamil and 24-hour ambulatory blood pressure monitoring in essential hypertension

The antihypertensive effects of oral regular and slow-release verapamil, a calcium-channel blocking agent, were evaluated in 22 patients with mild to moderate hypertension (sitting diastolic blood pressure [DBP] 95 to 112 mm Hg). The dose required to control blood pressure varied from 80 to 120 mg, 3 times a day. All patients received regular verapamil for a further 3 to 4 months, when systolic blood pressure (SBP) and DBP had risen from the end of the open-label phase. During a double-blind phase patients were randomly assigned to continue the same dose of regular verapamil, 3 times a day, or an equivalent daily dose of sustained-release verapamil (240 to 360 mg once a day). Seven of the 11 patients on regular and 3 of the 11 on sustained-release verapamil were also taking diuretics. This antihypertensive program was continued for at least 4 weeks. During the efficacy period, 24-hour ambulatory blood pressure monitoring was carried out. Mean 24-hour SBP and DBP were 133 +/- 20 and 89 +/- 13 mm Hg, respectively, on regular and 131 +/- 22 and 87 +/- 12 mm Hg, respectively, on sustained-release verapamil. There were no statistically significant differences noted between the 2 groups. Mean SBP and DBP varied similarly during awake and sleep hours with both formulations of verapamil. With regular verapamil, SBP was 139 +/- 18 and 124 +/- 20 mm Hg and DBP 92 +/- 11 and 84 +/- 13 mm Hg during awake and sleep hours, respectively; with sustained release, SBP was 138 +/- 21 and 122 +/- 22 mm Hg and DBP 92 +/- 10 and 80 +/- 10 mm Hg during awake and sleep hours, respectively. Heart rate fell during the entry period and continued during the entire study period. No other adverse effects were noted during the double-blind phase. In summary, verapamil is an effective antihypertensive medication and can be administered once a day as a sustained-release preparation; it is most useful in patients in whom adrenergic blocking drugs are indicated.     

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.     

Verapamil 240 SR versus verapamil 120 SR in arterial hypertension. A randomized double-blind,placebo-controlled study with 24-hour ambulatory blood pressure monitoring

Summary Fifteen patients (6 males, 9 females), age range 36–70 years, were enrolled in a randomized, double-blind, placebo-controlled study according to a Latin-square design, with the aim of comparing 24-hour blood pressure profiles after three 15-day treatment periods with placebo, verapamil SR 120 mg (V120 SR) given twice daily (bid), and verapamil SR 240 mg (V240 SR) given once daily (od.) All of the patients were diagnosed as mild or moderate essential hypertensives on the basis of standard casual recordings. Noninvasive 24-hour ambulatory blood pressure (BP) monitoring was performed with an ICR Spacelab 5200 automatic device. In comparison with placebo, a clinically and statistically significant reduction in both systolic and diastolic BP over 24 hours was obtained with both active treatments. Comparison of the two active treatments shows that V240 SR led to a greater reduction in systolic and diastolic BP than V120 SR. No changes in heart rate were observed. Both treatments were well tolerated. In conclusion, both verapamil regimens proved to be effective and safe in treating essential hypertensives, with V240 SR giving better 24-hour BP control.     

Current status of 24-hour ambulatory blood pressure monitoring in clinical practice

Twenty-four-hour monitoring of blood pressure (BP) is a new non-invasive technique of examination which, apart from becoming a useful research tool, has found widespread use in clinical practice. Monitoring detects BP fluctuations due to changes in physical and mental activities throughout the day and to physiological circadian rhythms, especially the nocturnal BP decrease. Monitored BP shows a better correlation with the degree of target organ damage than casual BP. In patients with increased BP values persisting despite therapy, BP monitoring makes it possible to differentiate hypertensives with truly resistant or inadequately treated hypertension from those showing substantially higher BP values in the doctor's office than their normal daytime levels are. BP monitoring may improve the accuracy of prediction of cardiovascular complications. This fact, however, has to be verified by other prospective studies which may expand the range of potential applications of this new method.     

A new portable device for 24-hour recording of ambulatory intra-arterial blood pressure and heart rate in hypertensive patients

A new portable device (measuring 14 X 11 X 5 cm, weighing 600 g) has been developed for recording ambulatory intra-arterial blood pressure (BP) and R-R intervals on the electrocardiogram at 10 sec intervals throughout a 24 hour period and a computer system for analysis of the 8,640 digital recordings of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). Using this device, SBP, DBP and HR recordings were obtained in 12 normotensive patients and 37 patients with essential hypertension (of whom 19 presented in WHO Stage I and 18 in WHO Stage II). The 24-hour BP variation (SD) increased with increasing 24 hour mean BP but there was no difference of statistical significance in SD/mean among the 3 groups. There was a good correlation (r = 0.70 to 0.94) between SBP and DBP during 24 hours. The average of A in the linear regression equation, SBP = A X DBP +B, was greatest for patients with WHO Stage I and the average of 24-hour HR was highest for this group. The results suggested that these patients were in a hyperdynamic cardiac state. The new portable SBP-DBP-HR recorder is easy and simple to use and has the advantage of being low-cost, and therefore will be useful in clinical applications.     

Hepatocyte growth factor and 24-hour ambulatory blood pressure monitoring.

In recent years, many growth factors and cytokines have been shown to be related to arteriosclerosis, and hepatocyte growth factor (HGF) has been reported to be associated with hypertension. In the present study, we investigated the relationship between HGF and hypertension by measuring the serum HGF concentration and performing 24-h ambulatory blood pressure monitoring (ABPM) in 47 randomly selected male and female subjects who underwent a medical examination for cardiovascular disease. The results were as follows. 1) The mean serum HGF concentration in the subjects was 0.35+/-0.14 ng/ml. 2) The serum HGF concentration was positively correlated with both the nighttime systolic and diastolic blood pressures (r=0.42, p<0.05 and r=0.47, p<0.01, respectively). 3) No correlation was found between serum HGF concentration and daytime systolic or diastolic blood pressure. 4) When subjects were divided into two groups based on the difference between daytime and nighttime systolic blood pressure, i.e., a group in which the difference was less than 10 mmHg and a group in which the difference was 10 mmHg or more, the HGF concentration was significantly higher in the former group (0.39+/-0.14 vs. 0.30+/-0.12 ng/ml, p<0.05); similarly, when subjects were divided into a group in which the difference between daytime and nighttime diastolic blood pressure was 5 mmHg and a group in which the difference was 5 mmHg or more, the HGF concentration was significantly higher in the former group (0.42+/-0.15 vs. 0.31+/-0.12 ng/ml, p<0.05). The results indicated that there is a relationship between blood pressure measured by ABPM and serum HGF concentration, and that this relationship might be an index of damage to blood vessels in patients with hypertension.