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.     

Effect of continuous positive airway pressure therapy on 24-hour blood pressure in patients with obstructive sleep apnea syndrome

BACKGROUND: Patients with obstructive sleep apnea syndrome (OSAS) are subject to an increased cardiovascular morbidity including systemic hypertension. Little is known about the effects of treatment with nasal continuous positive airway pressure (CPAP) on systemic hypertension. METHODS: Automated ambulatory 24-h blood pressure (BP) monitoring was performed in 88 consecutive patients who were referred for evaluation of snoring or suspected OSAS. In addition, the long-term effects of CPAP therapy on 24-h BP were assessed. RESULTS: A total of 62 patients had OSAS and 26 habitual snoring. Patients with OSAS had significantly higher mean arterial BP values than snorers (102.7 +/- 10.7 v 94.0 +/- 10.2 mm Hg; P < .01). Multiple stepwise linear regression analysis disclosed that the degree of systemic hypertension was independently associated with the severity of OSAS as determined by the apnea/hypopnea index (R = 0.43; P < .001), but not with age, body mass index, or smoking habits. Of the 62 patients with OSAS, 52 were treated with CPAP and reevaluated after 9 months. The CPAP resulted in a significant decrease in mean arterial BP (from 103.7 +/- 10.4 to 99.1 +/- 10.8 mm Hg; P < .05). For those patients with systemic hypertension whose BP improved with CPAP therapy, 24-h mean pulse pressure at baseline (r = -0.36; P < .05) as well as average heart rate during the day (r = -0.35; P < .05) turned out as predictors. CONCLUSIONS: Obstructive sleep apnea syndrome contributes, at least in part, to the development of systemic hypertension, and CPAP may improve BP values in treated OSAS patients. Predictors of a beneficial CPAP effect on BP are a high heart rate and a high pulse pressure before treatment.     

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.     

Effect of continuous positive airway pressure on ambulatory blood pressure in patients with obstructive sleep apnoea

OBJECTIVES: Previous reports on the effects of continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA) on blood pressure has shown contradictory results. Accordingly, we have investigated the effects of CPAP on blood pressure and on the potential reversal of the diagnosis of hypertension in patients with OSA evaluated repeatedly by ambulatory blood pressure monitoring. METHODS: We studied 122 patients (104 men and 18 women), 55.1+/-10.5 years of age, with diagnosis of OSA corroborated by overnight polysomnography at the clinic. Among those patients, 83 were treated with CPAP after their first evaluation, while 39 remained without CPAP for the duration of the trial. Blood pressure was measured by ambulatory monitoring at 20-min intervals during the day and at 30-min intervals at night for 48 consecutive hours, at baseline and after 2 and 4 months of intervention. RESULTS: There was a small, but not statistically significant, reduction in ambulatory blood pressure in patients treated with CPAP (0.7 and 1.5 mmHg in 24-h mean of systolic and diastolic blood pressure after 2 months of therapy; 2.0 and 2.3 mmHg after 4 months; P>0.239). The blood pressure reduction was very similar in patients with OSA followed for 4 months without CPAP (1.9 and 2.2 mmHg in 24-h mean of systolic and diastolic blood pressure, respectively; P=0.543). We found a high (77%) prevalence of hypertension among the patients participating in this study, although only 37% were receiving antihypertensive medication at the time of recruitment. The prevalence of hypertension was slightly but not significantly reduced to just 74% after 4 months of treatment with CPAP. CONCLUSIONS: The small reduction in blood pressure for consecutive profiles of ambulatory monitoring can probably be explained by the documented 'ABPM pressor effect' on patients using the ambulatory device for the first time. The high prevalence of hypertension among patients with OSA is not significantly reduced by treatment with CPAP. These results suggest that patients with OSA should always be properly evaluated for diagnosis of hypertension, and provided, if needed, with antihypertensive treatment apart from the recommended CPAP.     

Effects of age and 24-hour ambulatory blood pressure on rapid left ventricular filling

To determine the associations of age, blood pressure (BP) and cardiac structure with left ventricular (LV) diastolic performance, 47 subjects (21 normotensives and 26 age-matched, previously untreated hypertensives) were studied by 24-hour ambulatory BP monitoring, radionuclide ventriculography and sector-guided M-mode echocardiography. Normotension was defined as an awake ambulatory BP less than 130/80 mm Hg and hypertension as an awake ambulatory BP greater than 135/85 mm Hg. Univariate analyses revealed strong negative correlations of LV filling rate with age (r = -0.67, p less than 0.001), 24-hour systolic or diastolic BP (r = -0.59 for systolic BP and -0.57 for diastolic BP, p less than 0.001 for both) and a modest positive correlation with LV ejection fraction (r = 0.42, p less than 0.05). After multivariate analysis, significant dependencies of both the left atrial index and LV mass index on ambulatory BP were found, which negated the significance of the relation of these 2 cardiac structural variables with LV filling rate. The final regression equation predicted LV filling rate from age, BP and LV ejection fraction. Age was the most important single correlate of LV filling, as evidenced by the 14 of 16 subjects (88%) over the age of 53 years (8 hypertensives, 6 normotensives) who had reduced LV filling rates compared with only 9 of the remaining 31 subjects (29%, all hypertensives) under the age of 53 years with reduced LV filling rates. These data demonstrate that LV filling rate is more dependent upon age and BP than left atrial or LV size.(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。     

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.     

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。     

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)     

无创正压气道通气对老年脑梗死并阻塞性睡眠呼吸暂停患者预后的影响

目的探讨无创正压气道通气(CPAP)对老年脑梗死合并阻塞性睡眠呼吸暂停(OSA)患者24h动态血压和心脑血管事件的影响,并分析影响不良心脑血管事件的危险因素。方法选择鞍钢集团总医院2012年5月~2015年5月收治的老年脑梗死合并OSA患者145例,按照随机数字表分为治疗组(CPAP治疗)73例和对照组72例。评估2组患者24h动态血压,随访1年时,用Kaplan-Meier生存曲线评价2组的生存情况,采用ROC曲线分析预测心脑血管事件发生的危险因素。结果出院前2组24h收缩压、24h舒张压、昼间收缩压、昼间舒张压、夜间舒张压均有显著差异(P0.05)。随访1年时,Kaplan-Meier生存曲线显示,治疗组与对照组中位生存时间无显著差异(365dvs 362d,P0.05),治疗组心脑血管事件发生率显著低于对照组(21.9%vs 33.3%,P0.05)。ROC曲线显示,睡眠呼吸暂停指数的曲线下面积为0.70(95%CI:0.61~0.77,P=0.002)和24h收缩压的曲线下面积为0.72(95%CI:0.63~0.81,P=0.003),两者为预测心脑血管事件发生的危险因素。结论 CPAP能有效降低老年脑梗死合并OSA患者24h动态血压,降低心脑血管事件发生率。     

Effects of a slow-release nifedipine on 24-hour ambulatory blood pressure and ischemic changes on 24-hour ambulatory electrocardiogram in patients with severe coronary artery disease

Calcium antagonists have long been used as first-line drugs for hypertension and angina. However, deleterious effects have also been reported in patients treated with calcium antagonists. Thus, we evaluated the effect of a slow-release twice-daily formulation of nifedipine in 10 patients with severe coronary artery disease. Twenty-four-hour ambulatory electrocardiography (AECG) and blood pressure monitoring (ABPM) were performed simultaneously to detect any association between ischemic episodes on the ECG and changes in blood pressure (BP) and heart rate with and without nifedipine. Increased oxygen demand due to an increased systolic BP and heart rate was associated with ischemic episodes without nifedipine, while those with nifedipine were accompanied by a fall in diastolic BP and a rapid increase in heart rate. This slow-release twice-daily formulation of nifedipine may induce myocardial ischemia through a heart-rate increase and a decrease in coronary blood flow due to lower diastolic BP in patients with severe coronary artery disease. A once-daily formulation of nifedipine might be of great value for such patients.     

Effect of alcohol abstinence on blood pressure: assessment by 24-hour ambulatory blood pressure monitoring

Several studies have shown that cessation of alcohol drinking reduces blood pressure (BP). However, attempts to reproduce these findings by ambulatory BP monitoring (ABPM) have shown inconsistent results. The aim of the present study was to assess the effect of 1 month of proven abstinence from alcohol on the 24-hour BP profile in heavy alcohol drinkers. Forty-two men who were heavy drinkers (>100 g of pure ethanol per day) were consecutively admitted to a general ward for voluntary alcohol detoxification. On the day of admission, they received a total dose of 2 g/kg of ethanol diluted in orange juice in 5 divided doses, and a 24-hour ABPM was performed. A new 24-hour BP monitoring in the same environmental conditions was performed after 1 month of proven alcohol abstinence while the subjects were receiving the same amount of fluid but without the addition of alcohol. After 1 month of proven alcohol abstinence, BP and heart rate (HR) significantly decreased. The reduction was 7.2 mm Hg for 24-hour systolic BP (SBP) (95% CI, 4.5 to 9.9), 6.6 mm Hg for 24-hour diastolic BP (DBP) (95% CI, 4.2 to 9.0), and 7.9 bpm for HR (95% CI, 5.1 to 10.7). The proportion of alcoholic patients considered hypertensive on the basis of 24-hour BP criteria (daytime SBP >/=135 mm Hg or daytime DBP >/=85 mm Hg) fell from 42% during alcohol drinking to 12% after 1 month of complete abstinence. Abstinence did not modify either the long-term BP variability, assessed by SD of 24-hour BP, or its circadian profile. We conclude that abstinence in heavy alcohol drinkers significantly reduces BP assessed by 24-hour ABPM and that this reduction is clinically relevant. These results show that heavy alcohol consumption has an important effect on BP, and thus cessation of alcohol consumption must be recommended as a priority for hypertensive alcohol drinkers.     

Assessment of continuous positive airway pressure treatment in obstructive sleep apnea syndrome using 24-hour urinary catecholamines

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is related to diurnal sympathetic hyperactivity and increased blood pressure, both factors that are likely to lead to the development of cardiovascular disease. HYPOTHESIS: The study investigated whether 24-h urinary catecholamines would reflect the effect of obstructive sleep apnea on autonomic activity. METHODS: Standard polysomnography was performed in 17 patients with OSAS (age 53.7 +/- 13.5 years, mean +/- standard deviation). The number of apnea/hypopnea episodes per hour of sleep (apnea/hypopnea index [AHI]); number of oxygen desaturation episodes per hour (desaturation index [DSI]); arousals per hour (arousal index); lowest oxygen saturation (lowest SpO2); and percentages of stages 1, 2, 3/4, and rapid eye movement sleep (% stage 1, -2, and -3/4, and % REM, respectively) were measured. Overnight continuous positive airway pressure (CPAP) titration was performed the night after the baseline sleep measurements had been taken. Twenty-four-hour urinary adrenaline and noradrenaline were also examined. RESULTS: During the CPAP treatment, both 24-h urinary adrenaline and noradrenaline were significantly lower compared with natural sleep. Continuous positive airway pressure significantly decreased the AHI, DSI, % stage 1, and arousal index and significantly increased the lowest SpO2. There were no significant differences in % stage 2, % stage 3/4, and % REM between before and during CPAP treatment. Multiple analysis of covariance tests revealed that lowest SpO2 was the most important factor for increasing 24-h urinary noradrenaline levels (F = 4.75, p = 0.048). CONCLUSIONS: One night CPAP treatment could improve autonomic dysfunction. The assessment of 24-h urinary noradrenaline would provide important information for evaluating the effect of CPAP treatment.     

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.     

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.     

Evaluation of noninvasive blood pressure monitoring devices Spacelabs 90202 and 90207 versus resting and ambulatory 24-hour intra-arterial blood pressure.

This study evaluated the accuracy of blood pressure values provided by the Spacelabs 90202 and 90207 devices in comparison with intra-arterial recording in 19 subjects at rest and in nine subjects in ambulatory conditions (Oxford method). At rest Spacelabs monitors reflected intra-arterial systolic blood pressure values very closely but overestimated to a considerable extent intra-arterial diastolic blood pressure (Spacelabs-intra-arterial differences, -0.8 +/- 9.2, NS, and 9.1 +/- 8.8 mm Hg, p less than 0.01, for systolic and diastolic blood pressures, respectively). In ambulatory conditions Spacelabs-intra-arterial average differences in 24-hour values were +0.4 +/- 5.1 mm Hg for systolic blood pressure (NS) and +14.0 +/- 2.9 mm Hg for diastolic blood pressure (p less than 0.01) when group data were considered. The performance of both Spacelabs devices was worse when assessed in individual subjects or for each hourly interval. In spite of these differences between noninvasive and intra-arterial absolute blood pressure values, however, Spacelabs 90202 and 90207 monitors were able to faithfully reflect directional hour-to-hour changes in intra-arterial blood pressure (chi 2 = 18.2 and chi 2 = 23.1 for systolic and diastolic blood pressures, respectively, p less than 0.01). No differences were found between the performance of the two Spacelabs devices. Thus, although the absolute accuracy of blood pressure values provided by these monitors in ambulatory subjects is still limited, they seem to be suitable for studies aimed at assessing 24-hour blood pressure profiles quantitatively as well as qualitatively.