Limited reproducibility of 24-h ambulatory blood pressure monitoring

Abstract

Results of 24-h ambulatory blood pressure monitoring (ABPM) including average blood pressure, variability, and nocturnal dipping are considered the gold standard for diagnosis and the best predictor of the future end organ damage in chronic hypertension. Here we report on the reproducibility of ABPM results for these three measures over a period of months. A total of 35 hypertensive patients (43% female, mean age 64 years), underwent two separate ABPM recordings within 14 weeks, with unchanged medical treatment and lifestyle in the interim. The day and night average blood pressure, dipping status of systolic pressure, and the standard deviation of systolic and diastolic blood pressure as a measure of variability were compared between the two recordings. Individual values for average systolic and diastolic pressures showed only a modest correlation between the two measurements (r?=?0.56, r?=?0.81, p?<?0.01). Standard deviations of 24-h pressure were also positively but weakly correlated (r?=?0.4, p?<?0.001). The occurrence of dipping was reproducible in 71% of the patients. Average blood pressure, pressure variability, and dipping as assessed by ABPM are only moderately reproducible. Clinical decision-making based on single ABPM datasets should be made with caution, and repetition of ABPM seems justified in some cases.     

Out-patient versus in-hospital ambulatory 24-h blood pressure monitoring in heart transplant recipients

OBJECTIVE: To study the effect of the environment--in-hospital vs. out-patient situation--on blood pressure as measured by ambulatory blood pressure monitoring (ABPM). PATIENTS AND METHODS: Twenty-four hour ABPM was performed sequentially in-hospital and again 9+/-3 days later on an out-patient basis, in 30 consecutive heart transplant recipients (27 men, median age 56 years, median time post-transplant 3 years). The same equipment was used on both occasions, without any interim change in medical treatment. RESULTS: Both systolic and diastolic blood pressure were higher in-hospital than as an out-patient: +7+/-7 and +6+/-5 mm Hg respectively for the 24-h average (P<0.001). Daytime and night-time pressures were affected similarly. Depending on the specific cut-off values used, 37 to 87% of the individual patients were hypertensive in-hospital; 31 to 73% of these had an acceptable blood pressure as an out-patient. The converse was very rare (0 to 3% of the total group). CONCLUSIONS: In heart transplant patients blood pressure as assessed from 24-h ABPM is lower in the home environment than during a hospital stay. The post-transplant attenuation of the circadian variation in blood pressure is not influenced by the environment. Checking an unsatisfactory in-hospital ABPM with an outpatient recording may obviate the need for an (intensified) antihypertensive treatment in a substantial number of patients.     

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.     

Assessment of blood pressure in patients with Type 2 diabetes: comparison between home blood pressure monitoring, clinic blood pressure measurement and 24-h ambulatory blood pressure monitoring.

AIMS: To compare a home blood pressure (BP) monitoring device and clinic BP measurement with 24-h ambulatory BP monitoring in patients with Type 2 diabetes mellitus (DM). METHODS: Fifty-five patients with type 2 DM had BP measured at three consecutive visits to the DM clinic by nurses using a stethoscope and mercury sphygmomanometer (CBP). Twenty-four-hour ambulatory BP was measured using a Spacelabs 90207 automatic cuff-oscillometric device (ABPM). Subjects were then instructed in how to use a Boots HEM 732B semiautomatic cuff-oscillometric home BP monitoring device and measured BP at home on three specified occasions on each of 4 consecutive days at varying times (HBPM). RESULTS: Correlations between HBPM and ABPM were r = 0.88, P < 0.001 for systolic BP and r = 0.76, P < 0.001 for diastolic BP, with correlations between CBP and ABPM being systolic r = 0.59, P < 0.001, diastolic r = 0.47, P < 0.001. HBPM agreed with ABPM more closely compared with CBP (CBP +10.9/+3.8 (95% confidence intervals (CI) 6.9, 14.8/1.6, 6.1) vs. HBPM +8.2/+3.7 (95% CI 6.0, 10.3/2.0, 5.4)). The sensitivity, specificity and positive predictive value of HBPM in detecting hypertension were 100%, 79% and 90%, respectively, compared with CBP (85%, 46% and 58%, respectively). CONCLUSIONS: In patients with Type 2 DM, home BP monitoring is superior to clinic BP measurement, when compared with 24-h ambulatory BP, and allows better detection of hypertension. It would be a rational addition to the annual review process. Diabet. Med. 18, 431-437 (2001)     

24-h ambulatory blood pressure and retinopathy in normoalbuminuric IDDM patients

Summary The role of blood pressure elevation in the incidence and progression of diabetic retinopathy is not clearly established and results have been conflicting. Blood pressure and urinary albumin excretion (UAE) are closely related. In order to evaluate the independent relationship between retinopathy and blood pressure elevation, precise information on UAE is essential, as confounding by renal disease (incipient or overt), cannot otherwise be excluded.The aim of the present study was to evaluate the association between diabetic retinopathy and 24-h ambulatory blood pressure (AMBP) in a group of well-characterized normoalbuminuric IDDM patients. In 65 normoalbuminuric (UAE < 20 μg/min) IDDM patients we performed 24-h AMBP (Spacelabs 90 207) with readings at 20-min intervals. Fundus photographs were graded independently by two experienced ophthalmologists. UAE was measured by RIA and expressed as geometric mean of three overnight collections made within 1 week. HbA_{1 c} was determined by HPLC. Tobacco use and level of physical activity were assessed by questionnaire. Fifteen patients had no detectable retinal changes [grade 1], 35 had grade 2 retinopathy; and 15 had more advanced retinopathy [grade 3–6]. Diastolic night blood pressure was significantly higher in patients with diabetic retinopathy compared to patients without retinopathy (68 ± 8 mmHg [grade 3–6] and 65 ± 6 mmHg [grade 2], compared to 61 ± 4 mmHg [grade 1], p = 0.02). Diurnal blood pressure variation was significantly blunted in the patients with retinopathy as indicated by a higher night/day ratio of diastolic blood pressure (84.6 % ± 4 [grade 3–6], and 81.2 % ± 6 [grade 2] compared to 79.1 % ± 4 [grade 1], p = 0.01). Heart rate tended to be higher in patients in group 2 and 3–6 compared to patients without retinopathy with p values of 0.07 and 0.11 for day-time and 24 h values, respectively. Mean HbA_{1 c} increased significantly with increasing levels of retinopathy (p < 0.01). Patients were similar regarding sex, age, tobacco use, and level of physical activity. Notably, UAE was almost identical in the three groups (5.0 × /÷1.7 [grade 1], 3.9 × /÷1.8 [grade 2], and 5.1 × /÷1.6 μg/min [grade 3–6]). In conclusion, night blood pressure is higher and circadian blood pressure variation blunted in patients with retinopathy compared to patients without retinopathy despite strict normoalbuminuria and similar UAE levels in the groups compared. Our data suggest that the association between blood pressure and diabetic retinopathy is present also when coexisting renal disease is excluded. Disturbed diurnal variation of blood pressure is a pathophysiological feature related to the development of both retinopathy and nephropathy in IDDM patients. [Diabetologia (1998) 41: 105–110] Received: 27 May 1997 and in revised form: 5 September 1997     

Hormone replacement therapy does not affect 24-h ambulatory blood pressure in healthy non-smoking postmenopausal women

OBJECTIVE: Controversies surrounding the physiological effects of hormone replacement therapy (HRT) currently lie at the forefront of medicine. Important interindividual factors that affect blood pressure, such as smoking, body mass and sodium intake, may account for the conflicting findings seen in studies examining the effects of HRT on blood pressure. DESIGN: The study was a randomized, double-blind, placebo-controlled trial. METHODS: The effect of combination HRT and estrogen-only replacement therapy (ERT) on ambulatory blood pressure was examined in a sample of 46 healthy, normotensive, non-smoking, non-obese postmenopausal women between 45 and 65 years of age. Twenty-four hour urinary sodium excretion was examined prior to and following treatment. The women were randomized to 3 months' treatment with HRT, ERT or placebo. RESULTS: After treatment, there were no significant effects of either HRT or ERT on daytime or night-time systolic or diastolic blood pressure. Sodium excretion was similar across the groups. There were no effects of treatment on night-time blood pressure dipping. CONCLUSIONS: The findings from this prospective treatment study support the conclusion that HRT has no significant effect on daytime or night-time blood pressure in a sample of healthy, non-smoking postmenopausal women.     

Comparison between casual blood pressure and ambulatory blood pressure monitoring parameters in healthy and hypertensive adolescents

Casual blood pressure measurements were compared with mean ambulatory blood pressure values during wakefulness and sleep in 45 normotensive and 30 hypertensive adolescents of both sexes aged 10-18 years. Two sets of auscultatory casual blood pressure were obtained, one in a pediatric office setting (office blood pressure), performed by the physician, and one in the ambulatory blood pressure monitoring (ABPM) unit, performed by a trained nurse, prior to the initiation of ABPM (pre-ABPM blood pressure). In normotensive and hypertensive subjects of both sexes, the mean office systolic blood pressure (SBP) was lower than the mean pre-ABPM SBP, and the mean office diastolic blood pressure (DBP) was lower than the mean pre-ABPM DBP. In normotensive participants, the mean pre-ABPM SBP/DBP was lower than the mean ABPM SBP/DBP while awake, the mean ABPM SBP/DBP during sleep being lower than the mean ABPM SBP/DBP values while awake and the mean pre-ABPM SBP/DBP. No statistical difference was demonstrated between the mean office SBP and the mean ABPM SBP during sleep, the mean ABPM DBP during sleep being lower than the mean office DBP. The hypertensive adolescents presented a blood pressure profile similar to that of the normotensive group, albeit shifted upwards, with no significant difference between the mean pre-ABPM SBP and the mean ABPM SBP while awake but a higher mean pre-ABPM DBP than mean ABPM DBP while awake. This study suggests that, by evaluating the casual blood pressure in different environment/observer situations, the power of casual blood pressure to predict inadequate blood pressure control, manifested as abnormal ABPM parameters, can be enhanced. Our data indicate ABPM to be the method of choice for the early diagnosis and adequate follow-up of adolescent hypertension.     

早期慢性肾病患者动态血压变化与微量白蛋白尿的关系

目的分析早期慢性肾脏病（CKD）患者24h动态血压变化与尿微量白蛋白排泄率（UMAER）的关系。方法以25例正常人作为对照组（N组）,71例肾功能稳定的CKD1期患者作为疾病组（D组）。收集24h动态血压监测（ABPM）资料及肾功能、尿微量白蛋白（UMA）、尿肌酐（UCr）等临床资料,计算UMAER及其对数,分析早期D组24h动态血压变化特点及其与微量白蛋白尿（MAU）的关系。结果与N组相比,D组夜问收缩压、昼、夜及24小时平均舒张压均升高（P均〈0．05）;夜间收缩压下降率及舒张压下降率均低下（P均〈0．05）。D组高血压及非杓型血压发生率分别达47．9％、62．0％。与杓刭血压组相比,非杓型血压组Ln（UMAER）值及MAU发生率均增高（P均〈0．01）。相关性分析显示UMAER与夜间收缩压呈正相关（P〈0．05）、与夜间收缩压下降率及夜间舒张压下降率均呈负相关（P均〈0．05）。结论早期CKD患者即已出现血压升高及血压节律改变;MAU产生与早期CKD患者夜间高血压及非杓型血压关系更密切。     

Seven-day (24-h) ambulatory blood pressure monitoring,self-reported depression and quality of life scores

OBJECTIVE: Effects of environmental conditions on blood pressure (BP) and heart rate (HR) variations as putative factors underlying the onset of vascular events. METHODS: BP and HR were monitored around the clock for 7 days on 54 residents from Urausu, Hokkaido, Japan. Daytime, night-time, and 24-h means served to identify dippers and non-dippers. Questionnaire-assessed depression and subjective quality of life were related to BP and HR by analyses of variance and linear regression. Statistical significance was at 5%. RESULTS: A circaseptan (about 7-day) component characterizes the 24-h mean and standard deviation (SD) of HR, and the daytime and day-night ratio of systolic BP. The SD of HR is higher on weekends and lower on Mondays and Thursdays. When awake, systolic BP is lowest on Sundays and the day-night ratio is optimal on weekends (Saturdays: 15.7 +/- 9.4%; Sundays: 14.0 +/- 13.2%). Depression was detected in 15 subjects, who had higher mean systolic and diastolic BP values (systolic BP: P = 0.028 Fridays, P = 0.021 Tuesdays; diastolic BP: P = 0.022 Mondays, P = 0.006 daytime Mondays) and a lower day-night ratio of diastolic BP (P = 0.012 Tuesdays, P = 0.005 Wednesdays, and P = 0.038 Thursdays). A depressive mood correlated positively with 24-h averages of systolic (P = 0.037) and diastolic (P = 0.030) BP. CONCLUSIONS: Depression (and subjective quality of life) can affect BP and HR variability. The results indicate the role that psychological factors may play in the pathogenesis of cardiovascular disease. Therapeutic implications are suggested for primary and secondary prevention.     

Characteristic findings on 24-h ambulatory blood pressure monitoring in a series of patients with Parkinson's disease

BACKGROUND: Patients with Parkinson's disease frequently present with orthostatic hypotension, prompting testing with 24-h ambulatory blood pressure monitoring (ABPM). The aim of our study was to identify characteristic patterns of blood pressure changes present on ABPM in a series of patients with Parkinson's disease. METHOD: We retrospectively identified 13 patients with Parkinson's disease who had undergone ABPM for evaluation of symptomatic orthostatic hypotension. The ABPM tracings were analyzed for the presence or absence of reversal of circadian pattern, postprandial hypotension, noncompensatory heart rate variability, and average daytime and nocturnal blood pressure values. RESULTS: Reversal of circadian rhythm was identified in 92.3%, postprandial hypotension in 100% and nocturnal hypertension in 100% of the cases. Some 61.5% of the patients exhibited daytime blood pressures in the prehypertensive range, and 23% had blood pressures in the stage 1 hypertension range per JNC 7 classification. CONCLUSION: The characteristic findings on 24-h ABPM in this series of patients with Parkinson's disease were the presence of reversal of circadian rhythm (93%), postprandial hypotension (100%) and nocturnal hypertension (100%).     

24-h blood pressure monitoring in normal tension glaucoma: night-time blood pressure variability

Systemic arterial hypotension, hypertension and altered ocular blood flow are known risk factors in glaucoma. In this study, 24-h ambulatory blood pressure monitoring was performed in patients with normal tension glaucoma (NTG) and controls to evaluate blood pressure variability. In all, 51 patients with NTG and 28 age-matched controls were included in this prospective study. A 24-h ambulatory blood pressure monitoring (SpaceLabs Medical Inc., Redmond, USA) was performed and systolic, diastolic and mean arterial blood pressures were measured every 30 min during daytime (0800-2000) and night time (0000-0600). To evaluate blood pressure variability a variability index was defined as the s.d. of blood pressure measurements. Night-time blood pressure depression ('dip') was calculated (in percent of the daytime blood pressures). Patients with NTG exhibited higher night-time diastolic (P = 0.01) and mean arterial blood pressure values (P = 0.02) compared to controls, whereas systolic blood pressure data were not significantly different. The variability indices of night-time systolic, diastolic and mean arterial blood pressure measurements were significantly increased in patients with NTG compared to controls (P < 0.05). The night-time blood pressure depression of systolic (P = 0.47), diastolic (P = 0.11) and mean arterial blood pressures (P = 0.28) was not significantly different between patients with NTG and controls. In conclusion, patients with NTG showed increased variability of night-time blood pressure measurements compared to controls. Increased fluctuation of blood pressure may lead to ocular perfusion pressure fluctuation and may cause ischaemic episodes at the optic nerve head.     

Use of 24-h ambulatory blood pressure monitoring to assess blood pressure control: a comparison of olmesartan medoxomil and amlodipine besylate

OBJECTIVE: Olmesartan medoxomil is an angiotensin II receptor blocker with similar antihypertensive efficacy as the calcium channel blocker amlodipine besylate in patients with mild-to-moderate hypertension. In addition to a drug's ability to lower blood pressure, the effectiveness of the agent in enabling patients to achieve specific blood pressure targets is an important clinical consideration. This secondary analysis of a randomized, double-blind study compared the efficacy of olmesartan medoxomil with that of amlodipine besylate in achieving ambulatory blood pressure goals among patients with mild-to-moderate hypertension. METHODS: Following a 4-week placebo run-in, 440 study participants aged >or=18 years were randomized to olmesartan medoxomil (20 mg/day), amlodipine besylate (5 mg/day), or placebo for 8 weeks. The proportion of participants achieving specific systolic and diastolic ambulatory blood pressure goal levels was calculated by dividing the number of participants who had achieved a particular blood pressure goal by the total number of patients in the intent-to-treat population. RESULTS: After 8 weeks of treatment, a mean 24-h ambulatory blood pressure of <130/80 or <130/85 mmHg was achieved by significantly more participants in the olmesartan medoxomil group (18.1 and 30.4%, respectively) than in the amlodipine besylate (7.0 and 14.0%, respectively) or placebo (1.9% for both) groups. The target daytime ambulatory blood pressure of <135/85 mmHg was achieved by more participants in the olmesartan medoxomil group than in the amlodipine besylate group (15.8 vs. 5.8%, respectively; P<0.01). CONCLUSION: In a previous publication of the same study, we demonstrated that starting doses of olmesartan medoxomil and amlodipine besylate produced similar mean reductions in blood pressure. In this subanalysis of the blood pressure data from that primary publication, however, olmesartan medoxomil therapy was shown to result in a greater proportion of patients achieving specific ambulatory blood pressure goals than therapy with amlodipine besylate. As blood pressure goal attainment may be of more direct clinical relevance than numerical blood pressure lowering, the achievement of blood pressure goals should be a key efficacy parameter assessed in clinical trials of antihypertensive medications.     

Impact of gender on 24-h ambulatory blood pressure and target organ damage

Differences between male and female subjects in mean 24 h blood pressure (BP) values and target organ damage such as left ventricular mass (LVMASS) and intima-media thickness (IMT) of carotid arteries were explained. The study population consisted of 1,445 subjects. All subjects underwent 24 h ambulatory BP monitoring, left ventricular echocardiography and measurement of IMT of carotid arteries. Men and women did not differ in age, body mass index (BMI) and clinic BP values. Mean 24 h systolic and diastolic BP were significantly higher in men compared to women. LVMASS corrected for body surface area or height(2.7), IMT of common (MCCA) and internal (MICA) carotid arteries were found to be significantly higher in men compared to women. Analysis of covariance showed that men had significantly higher LVMASS, MCCA and MICA than women, after adjustment for BMI, age, smoking status, mean 24 h systolic and diastolic BPs, fasting serum glucose, total cholesterol and triglycerides. These findings indicate that male sex could be an important predictor of higher mean 24 h BP and target organ damage for subjects of similar BMI and clinic BP values.