Blood pressure measurement in research

Effects of an isocaloric healthy Nordic diet on ambulatory blood pressure in metabolic syndrome: a randomized SYSDIET sub-study

BACKGROUND/OBJECTIVES

Dietary pattern is central in the prevention of hypertension and blood pressure (BP)-related diseases. A diet based on healthy Nordic foods may have a favourable impact on BP. The objective was to clarify whether a Nordic alternative for a healthy food pattern would have beneficial effects on ambulatory BP in subjects with metabolic syndrome (MetS).

SUBJECTS/METHODS

In total, 37 subjects were randomized to either a healthy Nordic diet or a control diet. A healthy Nordic diet embraced whole grains, rapeseed oil, berries, fruits, vegetables, fish, nuts and low-fat dairy products of Nordic origin. The mean nutrient intake in the Nordic countries formed the control diet, embracing wheat products, dairy fat-based spread and a lower intake of fruits, vegetables and fish. Diets were isoenergetic. Ambulatory BP was monitored and 24-h urine was collected before and after 12 weeks of intervention.

RESULTS

After 12 weeks, ambulatory diastolic BP (-4.4 mm Hg; P=0.001) and mean arterial pressure (-4.2 mm Hg; P=0.006) were lowered by the healthy Nordic diet compared with the control diet, whereas changes in ambulatory systolic BP did not differ significantly between diets (-3.5 mm Hg; P=0.122). Heart rate tended to be lower in those on the healthy Nordic diet (P=0.057). Urinary sodium and potassium excretions were unaffected by diets and consequently not associated with the healthy Nordic diet-induced lowering of BP.

CONCLUSIONS

Consumption of Nordic varieties of health-enhancing foods for 12 weeks decreased diastolic ambulatory BP and mean arterial pressure in subjects with features of MetS during weight-stable condition, suggesting beneficial effects of a healthy Nordic dietary pattern on ambulatory BP.

Antihypertensive efficacy of olmesartan medoxomil and candesartan cilexetil assessed by 24-hour ambulatory blood pressure monitoring in patients with essential hypertension

OBJECTIVE

To compare the antihypertensive efficacy of olmesartan medoxomil with that of candesartan cilexetil after 1, 2 and 8 weeks of treatment.

DESIGN AND SETTING

Randomised, double-blind, parallel-group study conducted at 44 centres in Germany, Poland and the Czech Republic.

PATIENTS

643 patients (aged 19-86 years) with mainly mild-to-moderate essential hypertension received active double-blind treatment.

INTERVENTIONS

Following a 2-week placebo run-in, eligible patients were randomly assigned to receive olmesartan medoxomil 20mg (n = 319) or candesartan cilexetil 8mg (n = 324) once daily for 8 weeks.

MAIN OUTCOME MEASURES

Changes from baseline in daytime, 24-hour and night-time diastolic (DBP) and systolic (SBP) blood pressures assessed by ambulatory blood pressure monitoring (ABPM), and changes from baseline in sitting cuff DBP and SBP.

RESULTS

Mean decreases from baseline in daytime DBP by ABPM at weeks 1, 2 and 8 were 6.7, 8.4 and 9.3mm Hg, respectively, in the olmesartan medoxomil group compared with 5.3, 6.0 and 7.8mm Hg, respectively, in the candesartan cilexetil group. The between-group differences were significantly in favour of olmesartan medoxomil at all three timepoints (p </= 0.0126). Significant differences in favour of olmesartan medoxomil were also observed for mean 24-hour DBP and for mean daytime and 24-hour SBP by ABPM. Decreases from baseline in sitting cuff BP at trough were similar in the two groups (15-16mm Hg for DBP and 21mm Hg for SBP). Both treatments were well tolerated.

CONCLUSIONS

Olmesartan medoxomil reduced daytime and 24-hour DBP and SBP, assessed by ABPM, more effectively than candesartan cilexetil at the doses tested. The majority of the treatment effect in both groups was seen after only 1 or 2 weeks of dosing, when the between-group differences were already statistically significant.

Fermented milk for hypertension

BACKGROUND

Fermented milk has been suggested to have a blood pressure lowering effect through increased content of proteins and peptides produced during the bacterial fermentation. Hypertension is one of the major risk factors for cardiovascular disease world wide and new blood pressure reducing lifestyle interventions, such as fermented milk, would be of great importance.

OBJECTIVES

To investigate whether fermented milk or similar products produced by lactobacilli fermentation of milk proteins has any blood pressure lowering effect in humans when compared to no treatment or placebo.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (CENTRAL), English language databases, including MEDLINE (1966-2011), EMBASE (1974-2011), Cochrane Complementary Medicine Trials Register, Allied and Complementary Medicine (AMED) (1985-2011), Food science and technology abstracts (1969-2011).

SELECTION CRITERIA

Randomised controlled trials; cross over and parallel studies evaluating the effect on blood pressure of fermented milk in humans with an intervention period of 4 weeks or longer.

DATA COLLECTION AND ANALYSIS

Data was extracted individually by two authors, afterwards agreement had to be obtained before imputation in the review.

MAIN RESULTS

A modest overall effect of fermented milk on SBP was found (MD -2.45; 95% CI -4.30 to -0.60), no effect was evident on DBP (MD -0.67; 95% CI -1.48, 0.14).

AUTHORS' CONCLUSIONS

The review does not support an effect of fermented milk on blood pressure. Despite the positive effect on SBP the authors conclude, for several reasons, that fermented milk has no effect on blood pressure. The effect found was very modest and only on SBP, the included studies were very heterogeneous and several with weak methodology. Finally, sensitivity and subgroup analyses could not reproduce the antihypertensive effect. The results do not give notion to the use of fermented milk as treatment for hypertension or as a lifestyle intervention for pre-hypertension nor would it influence population blood pressure.

Sleep disturbance is associated with decreased daily activity and impaired nocturnal reduction of blood pressure in dementia patients

Our aim was to investigate the relationships between sleep disturbance and activities of daily living (ADL) and 24-h blood pressure patterns in institutionalized dementia patients. Using 107 institutionalized dementia patients (32 males and 75 females, mean age 76.3 years), patients with a mini mental state examination (MMSE) score<24 were classified into four groups based on ADL (normal or declined) and nocturnal reduction in blood pressure (dipper or non-dipper). The sleep/wake state was visually monitored hourly for 14 consecutive days, and daytime and nighttime sleep ratios were determined. MMSE scores were significantly lower in the declined ADL group than in the normal ADL group. The nighttime sleep ratio of the non-dipper/declined ADL group was significantly lower than in the other groups. Sleep disturbance was associated with the deterioration of MMSE scores, low ADL, and impaired nocturnal reduction in blood pressure in dementia patients.

The benefit of renal artery stenting in patients with atheromatous renovascular disease and advanced chronic kidney disease

BACKGROUND

Around 16% of all patients who present with atheromatous renovascular disease (ARVD) in the United States undergo revascularization. Historically, patients with advanced chronic kidney disease (CKD) have been considered least likely to show improvement in renal functional terms, or survival. We aimed to investigate whether differences in outcomes after revascularization compared to medical management might be observed in ARVD patients if stratified by their CKD classes.

METHODS

Two prospective cohorts, a UK center with a traditionally conservative approach, and a German center who undertook a proactive revascularization approach, were compared. An improvement in renal function was defined as > 20% renal improvement at one year's follow-up. To improve validity and comparability, revascularized patients in the UK center were also used within analyses,

RESULTS

347 (UK conservative group), 89 (UK revascularized group), and 472 (German center) patients were included in the analysis. When subdivided by CKD stage, patient ages between the two centers were comparable. Improvements in renal function were observed in twice as many patients who underwent revascularization as compared to medical treatment, particularly in the latter CKD stages, 15.2 (German revascularization) vs. 0% in CKD 1-2, 12.2 (UK), and 32.8 (German) revascularization vs. 14.1% in CKD3, and 53.1 and 53.8 vs. 28.3 in patients with CKD 4-5. The improvements in eGFR were 10.2 (16) and 8.1 (12.5) ml/min/year in the German and UK revascularized groups, respectively, vs. -0.05 (6.8) ml/min/year in the medical cohort in CKD 4-5. Improvements in blood pressure control were noted at 1 year overall and within each CKD category. Multivariate analysis revealed that revascularization independently reduced the risk of death by 45% in all patients combined (RR 0.55, P = 0.013).

CONCLUSIONS

Although this study has significant methodological limitations, it does shows that percutaneous renal revascularization can improve renal function in advanced CKD (stages 4-5), and that this can provide a survival advantage in prospective analysis.

Health-related quality of life (SF-36) during telemonitoring of home blood pressure in hypertensive patients: a randomized, controlled study

Telemonitoring of home blood pressure (BP) is a new advance in home BP monitoring (HBPM) and has proved effective in improving BP control. The impact of telemedical HBPM on health-related quality of life (HRQOL) has not yet been studied. The purpose of this study is to compare HRQOL using a generic scale (SF-36) in patients with antihypertensive treatment based on telemedical HBPM and in patients with antihypertensive treatment based on conventional monitoring of office BP. Hypertensive patients (n = 223) recruited by general practitioners participated in the study. In the intervention group, antihypertensive treatment was based on telemedical HBPM. In the control group, patients (n = 118) received usual care with office visits to monitor BP. After 6 months, participants filled out SF-36 questionnaires. Patients in the telemonitoring group (T) had higher mean scores in the bodily pain domain than patients in the control group (C), indicating less pain and interference with activities among telemonitored patients [T: 85.3(20.2), C: 78.3(26.4), p = 0.026)]. Patients were more likely to feel their general health had worsened during the last year if antihypertensive treatment was based on conventional office measurements. In the bodily pain domain and health transition scale, scores were slightly better among telemonitored patients compared with control patients.

The optimal schedule for self-monitoring of blood pressure by patients at home

The optimal schedule for home blood pressure monitoring should represent the usual level of home blood pressure, give a reproducible value, and have prognostic ability. Therefore, outcome studies, as well as short-term trials assessing the reproducibility of home blood pressure, its stability over time and its relationship with ambulatory blood pressure should be taken into account. A review of this evidence suggests that the optimal schedule should be based on 12-14 measurements, and even more measurements up to 25 are desirable. Morning and evening measurements should be obtained, with at least duplicate measurements per occasion. Measurements on the initial day should preferably be discarded.

Do we need out-of-office blood pressure in every patient?

PURPOSE OF REVIEW

The limitations affecting office blood pressure readings have spurred the development of techniques for measuring blood pressure out of a clinical environment. The increasing use of home and ambulatory blood pressure monitoring has allowed the identification of specific blood pressure patterns related either to a discrepancy between office and out-of-office blood pressure or to alterations in the 24-h blood pressure profiles. This review offers an update on the most recent data published on the above issues.

RECENT FINDINGS

A critical overview is provided on recent data published on blood pressure patterns suggested to have clinical relevance. These include white coat hypertension, the so-called masked hypertension, enhanced overall blood pressure variability over 24 h, a steeper morning blood pressure surge and a blunted or an excessive blood pressure fall at night.

SUMMARY

All of these different conditions have been variably reported to carry prognostic implications, and may represent specific targets for antihypertensive treatment. Their identification and management require information on out-of-office blood pressure, which suggests that self blood pressure monitoring at home or 24-h ambulatory blood pressure monitoring should be used more frequently in clinical practice, following the indications issued in recent guidelines.

Assessment of long-term antihypertensive treatment by clinic and ambulatory blood pressure: data from the European Lacidipine Study on Atherosclerosis

OBJECTIVES

Information on the features of long-term modifications of clinic and 24-h ambulatory blood pressure (ABP) by treatment is limited. The present study aimed to address this issue.

METHODS

Ambulatory BP monitoring and clinic BP (CBP) measurements were performed at baseline and at yearly intervals over a 4-year follow-up period in 1523 hypertensives (56.1 +/- 7.6 years) randomized to treatment with lacidipine or atenolol in the European Lacidipine Study on Atherosclerosis (ELSA).

RESULTS

CBP was always greater than ABP, while reductions in all BP values (greater for CBP than for ABP) were on average maintained throughout 4 years, CBP changes showing limited relationship with ABP changes (r = 0.14-0.27). BP reductions by treatment during daytime and night-time were correlated (r = 0.63-0.73). BP normalization was achieved in a greater percentage of patients for CBP (41.7%) than for ABP (25.3%), with systolic BP control being always less common than diastolic BP control. BP normalization was more frequent at single yearly visits than throughout the 4 years. Twenty-four-hour BP variability was reduced by treatment over 4 years in absolute but not in normalized units.

CONCLUSIONS

The present study provides the best evidence available on long-term effect of antihypertensive treatment on both ABP and CBP. On average, ABP was sustainedly reduced by treatment throughout the follow-up period, but 24-h BP was more difficult to control than CBP. In several patients, ABP control was unstable between visits, the percentage of patients under control over 4 years being much less than that of those controlled at each year. Treatment induced a reduction in absolute but not in normalized BP variability estimates. This has clinical implications because of the prognostic importance of ABP mean values and variability.

Blood pressure determination by traditionally trained personnel is less reliable and tends to underestimate the severity of moderate to severe hypertension

OBJECTIVE

Blood pressure determined by nurses has been observed to be unreliable. This study was conducted to compare the reliability of blood pressure measurements performed by traditionally trained nurses with those performed by a well-trained nurse and by an automatic device.

METHODS

Hypertensive patients in an outpatient clinic were studied. Each individual was subjected to three blood pressure measurements: the first one was performed by the traditionally trained nurse on duty at the time of study (TT nurse BP), the second one by a specifically trained nurse (ST nurse BP), both using sphygmomanometer; and the third one was done using Omron HEM-907 (digital BP).

RESULTS

A total of 907 participants were enrolled. More than 99% of both systolic and diastolic TT nurse BP ended with zero, demonstrating that they had terminal digit preference. ST nurse BP was in better agreement with digital blood pressure measurement than with TT nurse BP. The number of differences of < or =5 mmHg between ST nurse BP and digital blood pressure measurement was approximately 60% for both systolic and diastolic blood pressure. Overall, traditionally trained nurses overestimated, rather than underestimated, blood pressure. However, systolic blood pressure underestimation was extremely prominent in participants with moderate to severe hypertension. Systolic blood pressure underestimation of >5 mmHg was as high as 57.5% by traditionally trained nurses versus 33.8% by the automatic device, indicating that traditionally trained nurses tended to underestimate blood pressure in participants with more severe hypertension.

Primary-care physicians' views about the use of home/self blood pressure monitoring: nationwide survey in Hungary

OBJECTIVE

To obtain unbiased views of primary-care physicians about home blood pressure monitoring (HBPM).

METHODS

A mail survey was conducted in a random sample (n = 700) of all Hungarian primary-care physicians (n = 5112). Items in the questionnaire related to the extent and indications for use of HBPM, to the significance attributed to its results, to the methods of its use, and to concerns physicians had with HBPM.

RESULTS

Of the 700 questionnaires, 405 (58%) could be analysed. HBPM was popular among the respondents: 60% of them had more then 50 patients on HBPM, 90% of them were recommending its use either 'often' or 'almost all the time', and 75% of them considered the results of HBPM of either 'considerable' or of 'extreme importance'. The most frequent indications for use were white-coat hypertension (97%), assessing 24-h drug effects (87%), improving compliance (82%), suspicion of hypotension (63%), and resistant hypertension (61%). Physicians actively recommended devices with an upper-arm cuff (83%), equipped with a built in memory (63%). Most respondents (67%) had someone in their offices to teach the patient the correct measurement technique. Surprisingly, 65% of the physicians only reviewed the data to obtain a 'general picture' and did not analyse the data. Most of the respondents (78%) encouraged their patients to call their offices, and 90% of them did receive a call. Main concerns with HBPM were the use of non-validated devices (75%), and patient preoccupation with blood pressure (55%). Areas for suggested improvements were the need for patient training facilities (48%), established measurement protocols (44%) and better methods of displaying readings (30%).

CONCLUSIONS

We found an unexpected popularity in the use of HBPM among primary-care physicians. In order to fully exploit the benefits of HBPM, the concerns raised (validated devices, patient preoccupation) and areas to be improved upon (patient training, better methods of displaying results) will have to be addressed by researchers, societies and the industry.

Circadian blood pressure variation after acute stroke

We aimed to characterise the patterns of circadian blood pressure (BP) variation after acute stroke and determine whether any relationship exists between these patterns and stroke outcome. BP was recorded manually every 4 h for 48 h following acute stroke. Patients were classified according to the percentage fall in mean systolic BP (SBP) at night compared to during the day as: dippers (fall > or = 10-<20%); extreme dippers (> or = 20%); non-dippers (> or = 0-<10%); and reverse dippers (<0%, that is, a rise in mean nocturnal SBP compared to mean daytime SBP). One hundred and seventy-three stroke patients were included in the study (83 men, 90 women; mean age 74.3 years). Four patients (2.3%) were extreme dippers, 25 (14.5%) dippers, 80 (46.2%) non-dippers and 64 (36.9%) reverse dippers. There was a non-significant trend in the proportion of patients who were dead or dependent at 3 months in the extreme dipper (p=0.59) and reverse dipper (p=0.35) groups. Non-dipping and reverse-dipping were relatively common patterns of circadian BP variation seen in acute stroke patients. These patterns were not clearly associated with outcome.

Blood pressure measurement in research and in clinical practice: recent evidence

PURPOSE OF REVIEW

For over a century the technique of blood pressure measurement developed by Riva-Rocci and Korotkoff has provided most of the data on hypertension diagnosis and treatment. Its limitations, however, are becoming increasingly evident and therefore alternative solutions are under investigation. This paper is intended to provide an overview of important recent progress in this field, and to highlight future perspectives.

RECENT FINDINGS

A major development in blood pressure measurement is the technical improvement of electronic manometers for use either in the clinic (with the auscultatory approach, as an alternative to use of mercury columns), or in automated oscillometric devices yielding blood pressure measurements devoid of observer-dependency, and allowing long-term blood pressure monitoring. In the latter case, blood pressure measurement is made possible in settings other than the physician's office, either through ambulatory blood pressure monitoring or through self blood pressure measurement at home. These methods are growing in clinical importance, but further studies are needed to define their indications more precisely in the clinical evaluation of hypertensive patients. Recently, important steps towards better standards of blood pressure measurement have been taken, as summarized in the guidelines jointly issued by the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC), in the 7th Joint National Committee Report and (in even more detail) in the Blood Pressure Measurement Guidelines published by the ESH Working Group on Blood Pressure Monitoring.

SUMMARY

Blood pressure measurement is a rapidly developing field, the importance of which is increasingly acknowledged in the light of the growing awareness of the impact of hypertension on public health. Despite remarkable progress, many methodological issues still remain to be properly addressed.

Terminal digit bias in a specialty hypertension faculty practice

Traditional blood pressure (BP) methodology is subject to observer error such as terminal digit preference and single number preference leading to inaccuracies in measurement. A high percentage (60-90%) of terminal BP readings digit being zero has been reported from general medical- and hospital-based clinics. This study examined terminal digit preference in a hypertension specialty practice and assessed clinical factors that may be associated with zero preference in this setting. A retrospective chart review of patients presenting to the hypertension clinic at the University of Connecticut Health Center during the month of September 2001 was performed. Data were extracted on age, gender, height, weight, treatment status, and systolic and diastolic BP measurements taken by nursing staff and attending physicians. Terminal digit preference was apparent in BP readings taken by both nursing staff and physicians. Zero was the terminal systolic BP digit in 40% of readings taken by the nursing staff and 31% of readings taken by physicians. For diastolic BP readings, the percentages were 23 and 36%, respectively. Nurses also recorded 43% of diastolic BP readings with terminal digit 2. Age was significantly higher in those persons in whom the physician diastolic BP terminal digit was zero than in those with nonzero terminal digits (67+/-14 vs 59+/-18 years, P=0.008). Body mass index was lower in the patient group with diastolic terminal digit zero bias compared to those with nonzero terminal digits (28+/-5 vs 32+/-6 kg/m(2), P=0.02). In conclusion, although the frequency of zero digit preference did not reach the 60-80% levels found in previous studies, there was evidence of terminal digit preference in the systolic and diastolic measurements taken by nursing staff and attending physicians in a specialist hypertension clinic. We believe that the lower levels of terminal digit preference observed are an effect of increased training in proper BP measurement and technique. However, the observed bias in measurement even in a hypertension unit argues for regular monitoring and feedback to minimize such errors.