Ambulatory blood pressure monitoring in patients with chronic kidney disease and resistant hypertension

J Clin Hypertens (Greenwich). 2012; 14:611–617. © 2012 Wiley Periodicals, Inc. The role of ambulatory blood pressure (BP) monitoring (ABPM) has not been well‐studied in patients with chronic kidney disease and resistant hypertension. In a retrospective study of the outpatient chronic kidney disease population, 156 patients with chronic kidney disease and resistant hypertension who had 24‐hour ABPM and clinic BP measurements were identified. Resistant hypertension was defined as uncontrolled clinic BP while taking ≥3 medications including a diuretic or controlled BP while taking ≥4 medications. Within the study group, ambulatory BP <130/80 mm Hg was found in 35.9% of all patients. Only 6.4% had both ambulatory and clinic BP <130/80 mm Hg. Prevalence of white‐coat hypertension, masked hypertension, and sustained hypertension were 29.5%, 5.8%, and 58.3%, respectively. Compared with patients with sustained hypertension, more patients in the white‐coat hypertension group had low nocturnal average systolic BP (defined as nocturnal average systolic BP <100 mm Hg) (17.4% vs 0%) and low 24‐hour average diastolic BP (defined as 24‐hour average diastolic BP <60 mm Hg) (52.2% vs 22%, P<.01). ABPM provides more reliable assessment of BP in patients with chronic kidney disease and resistant hypertension.     

Pattern of Blood Pressure Response in Patients With Severe Asymptomatic Hypertension Treated in the Emergency Department

Severe asymptomatic hypertension (SAH) is a common cause of emergency department (ED) visits. Despite recommendations against using short‐acting blood pressure (BP)–lowering drugs in the ED, it is still a common practice. The authors characterized BP response in the ED utilizing 24‐hour ambulatory BP monitoring (ABPM). Patients with SAH who were not admitted to the hospital were recruited. All patients underwent 24‐hour ABPM. A total of 21 patients (14 females) with a mean age of 58±16 years were studied. BP decreased from 199±16/101±17 mm Hg to 154±34/83±23 mm Hg after 5 hours but then rose to 174±25/94±17 mm Hg after 19 hours. In 17 patients, systolic BP was ≥180 mm Hg after 6.7±5.3 hours. Two patients experienced severe hypotension (systolic BP <90 mm Hg). Thus, data from a single site in Israel support the current recommendations for management of SAH in the ED.     

动态血压监测中第一小时白大衣现象研究

目的探讨动态血压监测中存在的第1小时白大衣现象及其影响。方法选择2004-2005年门诊和病房住院的患者共626例（其中男性369例,女性257例）年龄范围13～90岁,平均年龄为（55．0±13．7）岁。所有观察对象测量诊室血压,在上午8：30—9：29之间开始监测24小时动态血压,将此期间检测的3次血压平均值作为第1小时血压。结果所有观察对象第1小时的平均收缩压和舒张压显著高于23h、白天、夜间和最后1H的平均水平（P〈0．01）,在不同年龄、性别组人群中也同样存在此种现象。女性中自大衣现象显著高于男性[第1小时平均血压一白天平均血压：女性：（9．5±13．4／6．0±7．8）mmHg（1mmHg：0．133kPa）;男性：（5．5±11．9／4．2±7．8）mmHg,P〈0．01],而各年龄组间差异无统计学意义。结论动态血压监测中,普遍存在着明显的第1小时内血压升高的现象,建议在临床上判断血压水平和诊断中,删除第1小时的记录数据,以便更加准确客观地反映患者的真实血压水平,在临床药物疗效观察评价及科学研究中尤其重要。     

Ambulatory blood pressure monitoring: which arm?

To determine the effects of routinely selecting the nondominant arm for ambulatory blood pressure monitoring (ABPM) on estimates of patients' blood pressure (BP) and to evaluate the practise of using manual BP from one arm and ambulatory BP from the other on the estimation of white coat effect (WCE), an observational study was conducted in 10 volunteers, exhibiting an interarm resting clinic systolic BP (SBP) difference > or =10 mm Hg. The main outcome measures were: (i) average ambulatory SBP measured on right and left arm simultaneously during 24 h, and (ii) estimate of WCE derived, by current practise, as the difference between the referral clinic BP (the higher of the manual readings from both arms) and ambulatory non-dominant arm BP, contrasted with the WCE calculated as the difference between clinic and ambulatory readings from the same arm (the arm with the higher manual readings). The supine referral clinic SBP was 16+/-6 mm Hg higher in the right compared with the left arm. Average 24 h ambulatory SBP was 6+/-7 mm Hg higher in the right arm (range +17 to -3 mm Hg), P = 0.025. Diastolic BP measurements mirrored the systolic findings. One-third of the WCE, estimated by current practise, could be attributed to inconsistency in the choice of arm for BP measurement. Thus, inconsistency in the selection of arms for BP measurement, by different techniques, may confound estimation of patients' cardiovascular morbidity risk.     

Diagnosis of white coat hypertension by ambulatory blood pressure monitoring.

White coat hypertension (WCH) is common in referred hypertensive patients. Ambulatory blood pressure monitoring (ABPM) is not free from the white coat syndrome. We examined the use of the elevation of the first and last measurements of ABPM for diagnosis of WCH in a hypertensive population that had been referred to a hospital-based hypertension unit. Data were obtained on 1350 patients for clinic and ABPM parameters. WCH, as diagnosed by conventional clinic blood pressure (BP) measurement, was compared with a variety of alternative methods determined from ABPM. In all cases, mean daytime pressure was <135 mm Hg/85 mm Hg with an elevation of clinic BP >/=140 mm Hg systolic or 90 mm Hg diastolic. The definitions tested for this elevation were first hour mean pressure, first reading, maximum reading in first hour, last hour mean pressure, last reading, maximum reading in the last hour and maximum reading in first or last hour. Elevation of the maximum pressure in the first hour or last hour above 140 mm Hg systolic or 90 mm Hg diastolic showed a high level of agreement (kappa=0.91) with classical WCH for diagnosis of the white coat syndrome. Termed ambulatory white coat hypertension, patients with this finding were older than classic white coat patients and had higher daytime (127+/-6/78+/-5 mm Hg versus 121+/-5.5/74+/-6 mm Hg, P<0.005 for systolic and diastolic) and nighttime (114+/-11/67+/-8 mm Hg versus 106+/-9/61+/-6 mm Hg, P<0.005 for systolic and diastolic) pressures. They also had a significantly greater Sokolow-Lyon index (leads V(1)+V(5), 21+/-7 mV versus 18+/-6 mV). Elevation of BP above 140 mm Hg systolic or 90 mm Hg diastolic in the first or last hour of monitoring diagnoses patients with a white coat response in whom there is a higher BP profile than in patients with classic white coat response alone. We suggest, therefore, that this is a better measure of the white coat phenomenon.     

Effects of aliskiren-based therapy on ambulatory blood pressure profile, central hemodynamics, and arterial stiffness in nondiabetic mild to moderate hypertensive patients

J Clin Hypertens (Greenwich). 2012;00:000–000. ©2012 Wiley Periodicals, Inc. Aliskiren is a direct renin inhibitor that exerts its effect at the rate‐limiting step of the renin‐angiotensin system. This study was performed to examine the beneficial effects of aliskiren‐based antihypertensive therapy on the ambulatory blood pressure (BP) profile, central hemodybamics, and arterial stiffness in untreated Japanese patients with mild to moderate hypertension. Twenty‐one Japanese nondiabetic patients with untreated mild to moderate essential hypertension were initially given aliskiren once daily at 150 mg, and the dose was titrated up to 300 mg as needed. After 12 weeks of aliskiren‐based therapy, the clinic, ambulatory, and central BP values as well as brachial‐ankle pulse wave velocity (baPWV) were all significantly decreased compared with baseline (clinic systolic BP, 151±11 mm Hg vs 132±11 mm Hg; clinic diastolic BP, 91±13 mm Hg vs 82±9 mm Hg; 24‐hour systolic BP, 144±12 mm Hg vs 133±11 mm Hg; 24‐hour diastolic BP, 88±8 mm Hg vs 81±9 mm Hg; central BP, 162±16 mm Hg vs 148±14 mm Hg; baPWV, 1625±245 cm/s vs 1495±199 cm/s; P<.05). These results show that aliskiren, as a first‐line regimen, improves the ambulatory BP profile and may have protective vascular effects in Japanese nondiabetic patients with untreated mild to moderate essential hypertension.     

Effects of the DASH Diet and Walking on Blood Pressure in Patients With Type 2 Diabetes and Uncontrolled Hypertension: A Randomized Controlled Trial

Data on the potential beneficial effects of combining diet and exercise on blood pressure (BP) are still scarce. A 4‐week randomized controlled clinical trial was undertaken in 40 hypertensive patients with type 2 diabetes with uncontrolled blood pressure (BP) in office and daytime ambulatory BP monitoring (ABPM). Patients were assigned to follow a Dietary Approaches to Stop Hypertension (DASH) diet associated with advice to increase walking using a pedometer (intervention group) or a diet based on the American Diabetes Association recommendations (control group). The lifestyle intervention caused a greater ABPM (mm Hg) reduction in systolic 24‐hour, diastolic 24‐hour, nighttime systolic, daytime systolic, and daytime diastolic measurements than observed in the control group. In the intervention group there was a decrease in urinary sodium and an increase in urinary potassium, plasma aldosterone, and the number of steps per day (P<.05). The DASH diet and increased walking were associated with clinically significant reductions in ABPM values in hypertensive patients with type 2 diabetes.     

Exaggerated Blood Pressure Response to Exercise Is Not Associated With Masked Hypertension in Patients With High Normal Blood Pressure Levels

The association between exaggerated blood pressure (BP) response to exercise (ExBPR) and “masked hypertension” is unclear. Medical records of patients with high‐normal BP who were evaluated in the Chaim Sheba Screening Institute Ramat Gan, Israel, during the years 2002–2007 and referred for 24‐hour ambulatory BP monitoring (ABPM) and exercise test were reviewed. Data on exercise tests performed in the preceding 5 years were retrieved. Reproducible ExBPR was defined when it was recorded at least twice. BP levels on 24‐hour ABPM were compared between patients with a normal BP response and those with an ExBPR (systolic BP ≥200 mm Hg). Sixty‐nine normotensive patients with high normal BP levels were identified. ExBPR was recorded in 43 patients and was reproducible in 28. BP levels on 24‐hour ABPM were similar in patients with and without ExBPR. In patients with high‐normal BP levels, ExBPR is not associated with masked hypertension.     

A comparison of two ambulatory blood pressure monitors, the Del Mar Avionics Pressurometer IV and the Spacelabs 90202

The purpose of this study was to evaluate the accuracy of two noninvasive ambulatory blood pressure (BP) monitors, the new Del Mar Avionics Pressurometer IV (PIV) and the second generation Spacelabs 90202. Two sets of comparisons were made between two trained observers and the monitors on 17 normotensive and 28 hypertensive subjects. The result of the first comparison showed that the average difference between observers and the PIV was 1.2/-2.2 mm Hg for systolic and diastolic BP. Comparisons of both monitors to the observers showed differences of 0.9/1.0 mm Hg for the PIV and 0.3/0.8 mm Hg for the 90202 (systolic/diastolic). Correlations between the average observer reading and the monitors over both sets of comparisons ranged from 0.90 (diastolic 90202 vs observer) to 0.98 (systolic PIV vs observer). The percentage of readings within 5 mm Hg between observer and monitor over all comparisons ranged from a low of 68% (90202, systolic and diastolic) to a high of 83% (PIV, diastolic). In general, both devices are satisfactory and reliable machines for ambulatory BP monitoring, but each has a slightly different bias compared to auscultatory readings.     

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.     

Reproducibility of ambulatory blood pressure monitoring in daily practice.

The reproducibility of ambulatory blood pressure monitoring (ABPM) was investigated in 45 untreated hypertensive patients in an out-patient clinic. Subjects with symptoms or diseases which could probably give rise to an increase in blood pressure (BP) variability were excluded. Patients underwent office BP (OBP) measurements and ABPM measurements with the Oxford Medilog device twice. The data were edited following previous set standards. Reproducibility of ABPM was good for the group: 24 h ABPM difference 0/2 mm Hg, standard deviation of the difference (SDD) 12/6 mm Hg for systolic BP and diastolic BP respectively. For OBP the difference between the two visits was 5/2 mm Hg with a SDD of 15/8 mm Hg. Intra-individual reproducibility was poor; almost half of the patients had a systolic difference of more than 10 mm Hg between both ABPM recordings. Reproduciblity of the day-night difference with a BP fall of at least 10% (dipper status) was moderate. About 60% of the subjects were dippers at one of the ABPM recordings but only 42% had a reproducible dip. Possible factors playing a role in the disappointing reproducibility of the ABPM recordings are the difference in daily activities between both recording days, decreased accuracy at higher BP, quality of sleep and the probable lower accuracy of the device during real ambulant conditions. In daily practice ABPM has no better reproducibility than OBP measurements, despite the larger number of measurements.     

Comparison of 44‐Hour and Fixed 24‐Hour Ambulatory Blood Pressure Monitoring in Dialysis Patients

The two most commonly used strategies to evaluate dialysis patients' blood pressure (BP) level are 44‐hour and 24‐hour ambulatory blood pressure monitoring (ABPM). The objective of this study was to find an appropriate 24‐hour period that correlated well with the 44‐hour BP level and determine the differences between these strategies. In a group of 51 dialysis patients, the authors performed 44‐hour ABPM and extracted data for a fixed 24‐hour ABPM. The fixed 24‐hour ABPM started at 6 am on the nondialysis day. A strong correlation was found between all parameters of 44‐hour and the fixed 24‐hour ABPM, with paired sample t test showing only small magnitude changes in a few parameters. Both 24‐hour ABPM and 44‐hour ABPM were superior to clinic BP in predicting left ventricular mass index (LVMI) by multiple regression analysis. It was found that 44‐hour ambulatory arterial stiffness index (AASI), but not 24‐hour AASI, had a positive association with LVMI (r=0.328, P=.021). However, after adjustment for 44‐hour systolic blood pressure, this association disappeared. Fixed 24‐hour ABPM is a good surrogate of 44‐hour ABPM to some extent, while 44‐hour ABPM can provide more accurate and detailed information.     

Prevalence of Masked Hypertension in African Americans

Masked hypertension (MH), the presence of normal office blood pressure (BP) with elevated ambulatory pressure, has been shown to correlate with organ damage. Population‐based studies from Europe and Asia estimate a prevalence of 8.5% to 15.8%. Two small studies in African Americans estimate a prevalence >40%. Therefore, the authors utilized ambulatory BP monitoring (ABPM) to identify the prevalence of MH in our African American population. Pressure was recorded every 30 minutes while awake and every 60 minutes while asleep. Patients with 24‐hour average BP ≥135/85 mm Hg, awake average BP ≥140/90 mm Hg, or asleep average BP ≥125/75 mm Hg had MH. Seventy‐three participates had valid data. The mean age of the patients was 49.8 years, mean body mass index was 31.1, and 39 patients (53%) were women. Thirty‐three patients (45.2%) had MH. Patients with MH had higher clinic systolic BP and trended toward higher BMI values. The authors corroborated the high prevalence of MH in African Americans. ABPM is critical to diagnose hypertension in African Americans, particularly in those with high‐normal clinic pressure and obesity.     

Simultaneous Compared With Sequential Blood Pressure Measurement Results in Smaller Inter‐Arm Blood Pressure Differences

There are currently few recommendations on how to assess inter‐arm blood pressure (BP) differences. The authors compared simultaneous with sequential measurement on mean BP, inter‐arm BP differences, and within‐visit reproducibility in 240 patients stratified according to age (<50 or ≥60 years) and BP (<140/90 mm Hg or ≥140/90 mm Hg). Three simultaneous and three sequential BP measurements were taken in each patient. Starting measurement type and starting arm for sequential measurements were randomized. Mean BP and inter‐arm BP differences of the first pair and reproducibility of inter‐arm BP differences of the first and second pair were compared between both methods. Mean systolic BP was 1.3±7.5 mm Hg lower during sequential compared with simultaneous measurement (P<.01). However, the first sequential measurement was on average higher than the second, suggesting an order effect. Absolute systolic inter‐arm BP differences were smaller on simultaneous (6.2±6.7/3.3±3.5 mm Hg) compared with sequential BP measurement (7.8±7.3/4.6±5.6 mm Hg, P<.01 for both). Within‐visit reproducibility was identical (both r=0.60). Simultaneous measurement of BP at both arms reduces order effects and results in smaller inter‐arm BP differences, thereby potentially reducing unnecessary referral and diagnostic procedures.     

Impact of Ambulatory Blood Pressure Monitoring on Reclassification of Hypertension Prevalence and Control in Older People in Spain

Ambulatory blood pressure monitoring (ABPM) accurately classifies blood pressure (BP) status but its impact on the prevalence and control of hypertension is little known. The authors conducted a cross‐sectional study in 2012 among 1047 individuals 60 years and older from the follow‐up of a population cohort in Spain. Three casual BP measurements and 24‐hour ABPM were performed under standardized conditions. Approximately 68.8% patients were hypertensive based on casual BP (≥140/90 mm Hg or current BP medication use) and 62.1% based on 24‐hour ABPM (≥130/80 mm Hg or current BP medication use) (P=.009). The proportion of patients with treatment‐eligible hypertension who met BP goals increased from 37.4% based on the casual BP target to 54.1% based on the 24‐hour BP target (absolute difference, 16.7%; P<.01). These results were consistent across alternative BP thresholds. Therefore, compared with casual BP, 24‐hour ABPM led to a reduction in the proportion of older patients recommended for hypertension treatment and a substantial increase in the proportion of those with hypertension control.     

True Resistant Hypertension Following Observed Drug Ingestion: A Systematic Evaluation

The authors investigated the role of poor drug adherence in treatment‐resistant hypertension following observed drug ingestion in 102 patients. Median blood pressures (BPs) were 170/91 mm Hg at referral, 153/84 mm Hg prior to, and 142/79 mm Hg during a 4‐ to 6‐hour period after drug ingestion. Median daytime ambulatory BP monitoring (ABPM) over the following 24 hours was 142/80 mm Hg. Median BP at a final follow‐up clinic visit was 147/79 mm Hg. The cumulative number of patients achieving a goal of <140/90 mm Hg in clinic or <135/85 mm Hg mean on ABPM was 57 (56%), with a further nine (9%) controlled at the final follow‐up clinic visit. Thus, 65% of patients achieved a systolic BP <140 mm Hg at any point immediately prior to, or after, drug ingestion; the residual 35% were considered to have true resistant hypertension. In conclusion, among patients with suspected resistant hypertension, a minority were truly treatment‐resistant following observed drug ingestion and BP monitoring.     

Central blood pressure variability is increased in hypertensive patients with target organ damage

We aimed to evaluate the association of aortic and brachial short‐term blood pressure variability (BPV) with the presence of target organ damage (TOD) in hypertensive patients. One‐hundred seventy‐eight patients, aged 57 ± 12 years, 33% women were studied. TOD was defined by the presence of left ventricular hypertrophy on echocardiogram, microalbuminuria, reduced glomerular filtration rate, or increased aortic pulse wave velocity. Aortic and brachial BPV was assessed by 24‐hour ambulatory BP monitoring (Mobil‐O‐Graph). TOD was present in 92 patients (51.7%). Compared to those without evidence of TOD, they had increased night‐to‐day ratios of systolic and diastolic BP (both aortic and brachial) and heart rate. They also had significant increased systolic BPV, as measured by both aortic and brachial daytime and 24‐hours standard deviations and coefficients of variation, as well as for average real variability. Circadian patterns and short‐term variability measures were very similar for aortic and brachial BP. We conclude that BPV is increased in hypertensive‐related TOD. Aortic BPV does not add relevant information in comparison to brachial BPV.     

Comparison of Aneroid and Oscillometric Blood Pressure Measurements in Children

Limited data exist on the comparison of blood pressure (BP) measurements using aneroid and oscillometric devices. The purpose of the study was to investigate the difference in BP obtained using oscillometric and aneroid BP monitors in 9‐ to 10‐year‐old children. A total of 979 children were divided into group O, which underwent two oscillometric BP readings followed by two aneroid readings, and group A, which had BP measured in the reverse order. No significant difference was found between the mean (±standard deviation) of the two systolic BP readings obtained using the oscillometric and aneroid devices (111.5±8.6 vs 111.3±8.1 mm Hg; P=.39), whereas the mean diastolic BP was lower with the oscillometric monitor (61.5±8.0 vs 64.5±6.8 mm Hg; P<.001). A significant downward trend in BP was observed with each consecutive measurement, and agreement between the two monitors was limited. Multiple BP measurements are, therefore, recommended before the diagnosis of elevated BP or hypertension is made with either method.     

Inter‐Arm Blood Pressure Differences in Young,Healthy Patients

The prevalence and magnitude of inter‐arm BP difference (IAD) in young healthy patients is not well characterized. Flight academy applicants and designated aviators undergo annual evaluation that includes blood pressure (BP) measurement on both arms. All BP measurements performed from January 1, 2012, to April 30, 2012, were recorded and IAD was calculated. Results were compared between patients in whom BP was initially measured in the right arm (group 1), those in whom BP was initially measured in the left arm (group 2), and those in whom the arm in which BP was initially measured was not recorded (group 3). A total of 877 healthy patients had BP measured during the study period. In the entire group, mean systolic BP was the same in both arms. Absolute IAD was 5.6±5.5 mm Hg for systolic and 4.7±4.5 mm Hg for diastolic BP. IAD >10 mm Hg was recorded in 111 (12.6%) and 77 (8.8%) patients for systolic and diastolic BP, respectively. IAD was the same in the 3 groups and was unrelated to age, body mass index, and heart rate, but was related to systolic BP. IAD is common in young healthy patients, is not dependent on which arm was measured first, and unrelated to age, body mass index, and heart rate.     

The first study comparing a wearable watch‐type blood pressure monitor with a conventional ambulatory blood pressure monitor on in‐office and out‐of‐office settings

Wearable blood pressure (BP) monitoring devices which measure BP levels accurately both in and out of the office are valuable for hypertension management using digital technology. The authors have conducted the first comparison study of BPs measured by a recently developed wrist‐worn watch‐type oscillometric BP monitoring (WBPM) device, the “HeartGuide,” versus BPs measured by an ambulatory BP monitoring (ABPM) device, A&D TM‐2441, in the office (total of 4 readings alternately measured in the sitting position) and outside the office (30‐minutes interval measurements during daytime) in 50 consecutive patients (mean age 66.1 ± 10.8 years). The 2 BP monitoring devices were simultaneously worn on the same non‐dominant arm throughout the monitoring period. The mean difference (±SD) in systolic BPs (average of 2 readings) between WBPM and ABPM was 0.8 ± 12.8 mm Hg (P = .564) in the office and 3.2 ± 17.0 mm Hg (P < .001) outside the office. The proportion of differences that were within ±10 mm Hg was 58.7% in the office and 47.2% outside the office. In a mixed‐effects model analysis, the temporal trend in the difference between the out‐of‐office BPs measured by the two devices was not statistically significant. In conclusion, the difference between the WBPM and ABPM device was acceptable both in and out of the office.