Home Blood Pressure Monitoring: Current Status and New Developments

Home blood pressure monitoring (HBPM) is a reliable, convenient, and less costly alternative to ambulatory blood pressure monitoring (ABPM) for the diagnosis and management of hypertension. Recognition and use of HBPM have dramatically increased over the last 20 years and current guidelines make strong recommendations for the use of both HBPM and ABPM in patients with hypertension. The accuracy and reliability of home blood pressure (BP) measurements require use of a validated device and standardized procedures, and good patient information and training. Key HBPM parameters include morning BP, evening BP, and the morning-evening difference. In addition, newer semi-automatic HBPM devices can also measure nighttime BP at fixed intervals during sleep. Advances in technology mean that HBPM devices could provide additional relevant data (e.g., environmental conditions) or determine BP in response to a specific trigger (e.g., hypoxia, increased heart rate). The value of HBPM is highlighted by a growing body of evidence showing that home BP is an important predictor of target organ damage, and cardiovascular disease (CVD)- and stroke-related morbidity and mortality, and provides better prognostic information than office BP. In addition, use of HBPM to monitor antihypertensive therapy can help to optimize reductions in BP, improve BP control, and reduce target organ damage and cardiovascular risk. Overall, HBPM should play a central role in the management of patients with hypertension, with the goal of identifying increased risk and predicting the onset of CVD events, allowing proactive interventions to reduce risk and eliminate adverse outcomes.

Left ventricular cardiac geometry and ambulatory blood pressure in children

Limited information is available regarding the relationship between ambulatory blood pressure monitoring (ABPM) and cardiac geometry in hypertensive children. ABPM and 2D-echocardiography were retrospectively reviewed in children and adolescents <21 years old with primary hypertension. A total of 119 participants (median age 15.0 [IQR 12, 16] years) with hypertension were included. Left ventricular hypertrophy was diagnosed in 39.5% of participants. Normal geometry was found in 47.1%, concentric remodeling (CR) in 13.4%, concentric hypertrophy (CH) in 15.1%, and eccentric hypertrophy (EH) in 24.4% of children. After adjustment for age, sex, and body mass index z-score, awake systolic blood pressure (BP) index (BPi) (OR 1.07, 95% CI: 1.001-1.14, P = 0.045), awake diastolic BPi (OR 1.04, 95% CI: 1.00-1.09, P = 0.048), awake systolic BP load (OR 1.02, 95% CI: 1.000-1.04, P = 0.047), and sleep systolic BP load (OR 1.02, 95% CI: 1.001-1.04, P = 0.03) were directly associated with CH. No ABPM parameters were significant predictors of EH. In conclusion, ABPM parameters were found to be independent predictors of cardiac geometry, specifically CH.

Patterns of ambulatory blood pressure: clinical relevance and application

Ambulatory blood pressure measurement (ABPM) is now recommended in all patients suspected of having hypertension. However, in practice, the mean daytime pressures are often used to make diagnostic and therapeutic decisions, and the information from abnormal patterns of blood pressure behavior is often overlooked. This paper presents daytime patterns (eg, white coat hypertension and siesta dipping), nocturnal patterns (eg, dipping, non-dipping, reverse dipping, and the morning surge), and discusses ambulatory hypotension, and abnormal patterns and indices of related hemodynamic parameters (eg, heart rate, pulse pressure, and blood pressure variability).

Effect of renal denervation on blood pressure in the presence of antihypertensive drugs: 6-month efficacy and safety results from the SPYRAL HTN-ON MED proof-of-concept randomised trial

BACKGROUND

Previous catheter-based renal denervation studies have reported variable efficacy results. We aimed to evaluate safety and blood pressure response after renal denervation or sham control in patients with uncontrolled hypertension on antihypertensive medications with drug adherence testing.

METHODS

In this international, randomised, single-blind, sham-control, proof-of-concept trial, patients with uncontrolled hypertension (aged 20-80 years) were enrolled at 25 centres in the USA, Germany, Japan, UK, Australia, Austria, and Greece. Eligible patients had an office systolic blood pressure of between 150 mm Hg and 180 mm Hg and a diastolic blood pressure of 90 mm Hg or higher; a 24 h ambulatory systolic blood pressure of between 140 mm Hg and 170 mm Hg at second screening; and were on one to three antihypertensive drugs with stable doses for at least 6 weeks. Patients underwent renal angiography and were randomly assigned to undergo renal denervation or sham control. Patients, caregivers, and those assessing blood pressure were masked to randomisation assignments. The primary efficacy endpoint was blood pressure change from baseline (measured at screening visit two), based on ambulatory blood pressure measurements assessed at 6 months, as compared between treatment groups. Drug surveillance was used to assess medication adherence. The primary analysis was done in the intention-to-treat population. Safety events were assessed through 6 months as per major adverse events. This trial is registered with ClinicalTrials.gov, number NCT02439775, and follow-up is ongoing.

FINDINGS

Between July 22, 2015, and June 14, 2017, 467 patients were screened and enrolled. This analysis presents results for the first 80 patients randomly assigned to renal denervation (n=38) and sham control (n=42). Office and 24 h ambulatory blood pressure decreased significantly from baseline to 6 months in the renal denervation group (mean baseline-adjusted treatment differences in 24 h systolic blood pressure -7·0 mm Hg, 95% CI -12·0 to -2·1; p=0·0059, 24 h diastolic blood pressure -4·3 mm Hg, -7·8 to -0·8; p=0.0174, office systolic blood pressure -6·6 mm Hg, -12·4 to -0·9; p=0·0250, and office diastolic blood pressure -4·2 mm Hg, -7·7 to -0·7; p=0·0190). The change in blood pressure was significantly greater at 6 months in the renal denervation group than the sham-control group for office systolic blood pressure (difference -6·8 mm Hg, 95% CI -12·5 to -1·1; p=0·0205), 24 h systolic blood pressure (difference -7·4 mm Hg, -12·5 to -2·3; p=0·0051), office diastolic blood pressure (difference -3·5 mm Hg, -7·0 to -0·0; p=0·0478), and 24 h diastolic blood pressure (difference -4·1 mm Hg, -7·8 to -0·4; p=0·0292). Evaluation of hourly changes in 24 h systolic blood pressure and diastolic blood pressure showed blood pressure reduction throughout 24 h for the renal denervation group. 3 month blood pressure reductions were not significantly different between groups. Medication adherence was about 60% and varied for individual patients throughout the study. No major adverse events were recorded in either group.

INTERPRETATION

Renal denervation in the main renal arteries and branches significantly reduced blood pressure compared with sham control with no major safety events. Incomplete medication adherence was common.

FUNDING

Medtronic.

Endovascular ultrasound renal denervation to treat hypertension (RADIANCE-HTN SOLO): a multicentre, international, single-blind, randomised, sham-controlled trial

BACKGROUND

Early studies suggest that radiofrequency-based renal denervation reduces blood pressure in patients with moderate hypertension. We investigated whether an alternative technology using endovascular ultrasound renal denervation reduces ambulatory blood pressure in patients with hypertension in the absence of antihypertensive medications.

METHODS

RADIANCE-HTN SOLO was a multicentre, international, single-blind, randomised, sham-controlled trial done at 21 centres in the USA and 18 in Europe. Patients with combined systolic-diastolic hypertension aged 18-75 years were eligible if they had ambulatory blood pressure greater than or equal to 135/85 mm Hg and less than 170/105 mm Hg after a 4-week discontinuation of up to two antihypertensive medications and had suitable renal artery anatomy. Patients were randomised (1:1) to undergo renal denervation with the Paradise system (ReCor Medical, Palo Alto, CA, USA) or a sham procedure consisting of renal angiography only. The randomisation sequence was computer generated and stratified by centres with randomised blocks of four or six and permutation of treatments within each block. Patients and outcome assessors were blinded to randomisation. The primary effectiveness endpoint was the change in daytime ambulatory systolic blood pressure at 2 months in the intention-to-treat population. Patients were to remain off antihypertensive medications throughout the 2 months of follow-up unless specified blood pressure criteria were exceeded. Major adverse events included all-cause mortality, renal failure, an embolic event with end-organ damage, renal artery or other major vascular complications requiring intervention, or admission to hospital for hypertensive crisis within 30 days and new renal artery stenosis within 6 months. This study is registered with ClinicalTrials.gov, number NCT02649426.

FINDINGS

Between March 28, 2016, and Dec 28, 2017, 803 patients were screened for eligibility and 146 were randomised to undergo renal denervation (n=74) or a sham procedure (n=72). The reduction in daytime ambulatory systolic blood pressure was greater with renal denervation (-8·5 mm Hg, SD 9·3) than with the sham procedure (-2·2 mm Hg, SD 10·0; baseline-adjusted difference between groups: -6·3 mm Hg, 95% CI -9·4 to -3·1, p=0·0001). No major adverse events were reported in either group.

INTERPRETATION

Compared with a sham procedure, endovascular ultrasound renal denervation reduced ambulatory blood pressure at 2 months in patients with combined systolic-diastolic hypertension in the absence of medications.

FUNDING

ReCor Medical.

Parenting stress, salivary biomarkers, and ambulatory blood pressure: a comparison between mothers and fathers of children with autism spectrum disorders

Parents of children with autism spectrum disorders (ASD) may experience higher levels of stress and health problems than parents of children with typical development. However, most research has focused on mothers, with emphasis on parent-reported stress and wellbeing. This study compared parenting responsibility, distress, anxiety, depression, cortisol, alpha-amylase, and cardiovascular activity between 19 mother-father dyads of children with ASD. Mothers reported higher parenting responsibility, distress, anxiety, and depression than fathers, while fathers had higher blood pressure and heart rate variability. Mothers and fathers had lower than average morning cortisol levels, suggesting stress effects on the hypothalamic-pituitary-adrenal-axis. Parents of children with ASD may benefit from routine health screening (particularly adrenal and cardiovascular function) and referral for stress reduction interventions or supports.

[Trends in the use of antihypertensive drugs in France from 2002 to 2012: FLAHS surveys]

OBJECTIVE

To evaluate from studies conducted between 2002 and 2012, trends in the use of antihypertensive drugs in France.

METHOD

French League Against Hypertension Survey (FLAHS) were conducted in a representative sample of subjects aged 35 and over living in France. A list including the names for all antihypertensive drugs marketed at the time of each survey made it possible to detail drug therapies employed. Data analysis has taken the patient as a unity. The data obtained in 2002, 2007 and 2012 are subject to this analysis.

RESULTS

In 2012, 30% of the French population aged 35 and older was treated with antihypertensive drugs (11.4 million), while 24% were treated in 2002 (8.2 million). On average, prescription of antihypertensive included 1.4 ± 0.7 pills in 2002, 1.5 ± 0.8 in 2007 and 1.8 ± 0.9 in 2012, which corresponds to a pharmacological monotherapy prescribed in 47% of subjects in 2012, a different percentage than in 2007 (46%) and 2002 (56%). Over the period, the percentage of prescriptions of diuretics (41% to 42%) and ACE inhibitors (24% to 23%) and beta-blockers (35% to 36%) is stable, but they are increasing with ARBs (23% to 47%) and calcium antagonists (24% to 34%). The prescriptions of fixed-dose combinations were also increased (19% to 30%). In 2012, fixed-dose combinations included a diuretic (79%), an ARB (65%), an ACEI (23%) and a calcium antagonist (20%). Blood pressure control estimated with home blood pressure monitoring increases from 38% in 2002 to 50% in 2007 and 2012.

CONCLUSION

Changes in the use of antihypertensive drugs in France between 2002 and 2012 led to the prescription of antihypertensive treatment with associations in the majority. ARBs or ACEI are present on 70% of prescriptions with diuretics combined in 80%. Extensive use of fixed-dose combinations with diuretics and ARA2 characterizes this period in which it was observed an increase in blood pressure control in France.

The International Database of HOme blood pressure in relation to Cardiovascular Outcome (IDHOCO): moving from baseline characteristics to research perspectives

The objective of this study is to construct an International Database of HOme blood pressure in relation to Cardiovascular Outcome (IDHOCO). The main goal of this database is to determine outcome-based diagnostic thresholds for the self-measured home blood pressure (BP). Secondary objectives include investigating the predictive value of white-coat and masked hypertension, morning and evening BP, BP and heart rate variability, and the home arterial stiffness index. We also aim to determine an optimal schedule for home BP measurements that provides the most accurate risk stratification. Eligible studies are population-based, have fatal as well as nonfatal outcomes available for analysis, comply with ethical standards, and have been previously published in peer-reviewed journals. In a meta-analysis based on individual subject data, composite and cause-specific cardiovascular events will be related to various indexes derived by home BP measurement. The analyses will be stratified by a cohort and adjusted for the clinic BP and established cardiovascular risk factors. The database includes 6753 subjects from five cohorts recruited in Ohasama, Japan (n=2777); Finland (n=2075); Tsurugaya, Japan (n=836); Didima, Greece (n=665); and Montevideo, Uruguay (n=400). In these five cohorts, during a total of 62 106 person-years of follow-up (mean 9.2 years), 852 subjects died and 740 participants experienced a fatal or nonfatal cardiovascular event. IDHOCO provides a unique opportunity to investigate several hypotheses that could not reliably be studied in individual studies. The results of these analyses should be of help to clinicians involved in the management of patients with suspected or established hypertension.

Masked hypertension, a review of the literature

Masked hypertension (blood pressure that is normal in the physicians' office but elevated elsewhere) is a common phenomenon as prevalence among studies varies from 8 to 45% and is seen at all ages. large discrepancies, however, exist between studies that have dealt with masked hypertension. It is of high clinical importance as it is associated with higher target organ damage as compared with sustained normotension. Therefore more research should be determined. This paper provides an overview of current literature to improve knowledge about masked hypertension and about the cause of this phenomenon. In addition it provides some questions, which need to be answered for performing appropriate research into this subject in future.

Cost-effectiveness of ambulatory blood pressure monitoring in the follow-up of hypertension

AIMS

To study the cost of the follow-up of hypertension in primary care (PC) using clinical blood pressure (CBP) and ambulatory blood pressure monitoring (ABPM), and to analyse the cost-effectiveness (CE) of both methods.

MAJOR FINDINGS AND PRINCIPAL CONCLUSION

Good control of hypertension was achieved in 8.3% with CBP (95% CI 4.8-11.8) and in 55.6% with ABPM (95% CI 49.3-61.9). The cost of one patient with good control of hypertension is almost four times higher with CBP than with ABPM (Euro 940 vs Euro 238). Reaching the gold standard (ABPM) involved an after-cost of Euro 115 per patient. The results for a 5% discount rate showed a saving of Euro 68,883 if ABPM was performed in all the patients included in the study (n = 241, Euro 285 per patient). An analysis of sensitivity, changing the discount rate and life expectancy indicated that ABPM provides a better CE ratio and a lower global cost. ABPM is more cost-effective than CBP. However, if we include the new treatment cost of poorly monitored patients, it is less cost-effective. Excellent control of hypertension is still an important challenge for all healthcare professionals, especially for those working in PC, where most monitoring of hypertensive patients takes place.

Devices for ambulatory and home monitoring of blood pressure, lipids, coagulation, and weight management, part 1

PURPOSE

The equipment and methods used for ambulatory and home monitoring of blood pressure, lipids, coagulation, and weight management are discussed.

SUMMARY

Over 100 million people in the United States have one or more chronic diseases, such as diabetes, hypertension, and asthma. With the goal to improve health while reducing costs and the overall health care burden, ambulatory and home monitoring by pharmacists and patients are receiving more attention. Ambulatory and home monitoring of blood pressure, cholesterol, coagulation, and weight management (including devices for assessing overweight and obese patients, heart rate monitors, and pedometers) are convenient for clinicians and patients. Such monitoring provides pharmacists with an opportunity to differentiate their practices. Studies suggest that patients who are involved in ambulatory and home monitoring take a more active role in their health and may have better adherence to prescribed diet and medication regimens. Studies also show that ambulatory and home monitoring, if done correctly, provide clinicians with a large quantity of reliable readings for future therapeutic decisions. Devices are also a means for pharmacists to increase their provision of pharmacy services. Ambulatory monitoring is billable in many clinic settings, and the devices can be a profitable addition to prescription services.

CONCLUSION

Many devices are available to assist patients and clinicians in monitoring blood pressure, lipids, coagulation, and weight management. Familiarity with the devices will help in their proper selection and use.

Visit frequency and hypertension

The best return visit interval to achieve blood pressure control is currently unknown. This study investigates the relationship between return visit interval and percent change in blood pressure. We reviewed a cohort of hypertensive patient charts from two large, urban family practice offices. Four hundred twenty-nine patients with 7910 intervals showed a mean return visit interval of 79.5 days. Blood pressure control occurred during 34.5% of office visits. Pearson's r correlation coefficients between return visit interval and percent change in systolic and diastolic blood pressure demonstrated a small but statistically significant correlation. Shorter return visit intervals were associated with better percent changes in blood pressure. The return visit interval may be a simple and useful tool to improve management of hypertension.

Chronomic community screening reveals about 31% depression, elevated blood pressure and infradian vascular rhythm alteration

Depression, which is a risk factor for cardiac morbidity and mortality, is not an unusual occurrence among individuals with coronary heart disease (CHD), but evidence concerning its role in the pathogenesis of this condition is less clear. Ambulatory blood pressure monitoring (ABPM) has become an important tool in the diagnosis and management of hypertension. Several previous studies have indicated that various kinds of target organ damage and cardiovascular morbidity are more strongly associated with a diagnosis by ABPM than through spot-checks in a clinical setting. This study investigated whether depressive mood was associated with changes in the about-weekly (circaseptan) and half-weekly (circasemiseptan) variations in blood pressure (BP) and heart rate (HR), including a BP surge on Mondays, in community-dwelling subjects monitored chronomically for the time structure (chronome) of their BP and HR variabilities. From April 2001 to April 2003, 217 subjects (85 men and 132 women; mean age: 56.8 +/- 11.3 yr) from U town, Hokkaido (latitude: 43.45 degrees N, longitude: 141.85 degrees E), self-monitored their BP and HR for 7 days starting around 11 a.m. on Thursday, and took readings at 30-minute intervals between 7 a.m. and 10 p.m., then at 60-minute intervals between 10 p.m. and 7 a.m. The data were retrieved and analyzed on a PC with appropriate commercial software (TM-2430-15; A&D Co., Japan). Subjects were asked about 15 items on a depression rating scale through a self-administered questionnaire. When the score amounted to 5 or higher, subjects were considered to be depressive. Student's t-test, a one-way analysis of variance (ANOVA), and cosinor methods with parametric tests were also used. A p-value below 0.05 was considered to indicate statistical significance (below 0.10: borderline statistical significance). Depression rating scales were obtained for 192 out of the 217 subjects enrolled in this study. Depression scores were (>) 5 in 72 subjects. The average values of systolic (S) and diastolic (D) BP were statistically significantly higher in depressed subjects (SBP: 129.2 vs 124.5 mmHg; p = 0.034; DBP: 79.0 vs 76.5 mmHg; p = 0.041). The 7-day average for HR did not differ between subjects with depression scores of < 5 or > 5. DBP dipping was less in the depressed subjects (16.30 vs 18.22%; p = 0.048). The dipping ratios of SBP and HR showed no statistically significant difference. In the group with depression scores of < 5, HR variability (estimated by the SD of HR and HR dip) was higher during vacations and lower on Mondays. The 24-h BP measures showed a novelty effect and a surge on Mondays. In the depressed group, a prominent circaseptan rhythm appeared to replace the novelty effect, vacation dip, and Monday surge. The results of this investigation indicate the clinical importance of the monitoring of depressed subjects. Fewer than 7 days of monitoring means a greater risk of false diagnosis, and thus a therapeutic decision including potentially unnecessary or inappropriate long-term treatment. Records shorter than 7 days would not have detected circaseptan BP dysrhythmia associated with a depressive state. Prominent circaseptans can provide new indications on the mechanisms underlying the strong relation between depression and adverse cardiac events. Future studies should aim at determining whether the treatment of depression, especially from the standpoint of a chronodiagnosis and chronotherapy, can reduce the incidence of adverse cardiac events, and whether this depends upon restoring normal BP and HR variability, i.e. anormal BP and HR chronome.

Current status of ambulatory blood pressure monitoring

During the past few years, 24 h ambulatory blood pressure (BP) monitoring has become an essential tool in the management of hypertensive patients. Individuals who exhibit increases in BP only in the office setting (white coat hypertension) can now avoid unnecessary drug therapy. For patients with treated hypertension, ambulatory BP monitoring has provided a means to detect individuals at increased risk of experiencing a cardiovascular event independent of the office BP reading. Alternatives to BP monitoring, such as self-measurement in the home, do exist, but the interpretation of findings reported by patients must be scrutinized carefully to take into account the use of nonvalidated devices and the possibility of "reporting bias". Automated BP recording devices have recently been introduced into the office setting and are likely to become more commonplace over the next few years. The Canadian Hypertension Education Program recommends the assessment of hypertensive patients with ambulatory BP monitoring in accordance with specific guidelines for the diagnosis of hypertension and the detection of a white coat effect in treated patients who are having difficulty reaching target BP levels.

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.

Home blood pressure monitoring. Current knowledge and directions for future research

Home blood pressure (BP) monitoring has become popular in clinical practice and several automated devices for home BP measurement are now recommendable. Home BP is generally lower than clinic BP, and similar to daytime ambulatory BP. Home BP measurement eliminates the white coat effect and provides a high number of readings, and it is considered more accurate and reproducible than clinic BP. It can improve the sensitivity and statistical power of clinical drug trials and may have a higher prognostic value than clinic BP. Home monitoring may improve compliance and BP control, and reduce costs of hypertension management. Diagnostic thresholds and treatment target values for home BP remain to be established by longitudinal studies. Until then, home BP monitoring is to be considered a supplement. However, high home BP may support or confirm the diagnosis made in the doctor's office, and low home BP may warrant ambulatory BP monitoring. During long-term follow-up, home BP monitoring provides an opportunity for close attention to BP levels and variations. The first international guidelines have established a consensus document with recommendations, including a proposal of preliminary diagnostic thresholds, but further research is needed to define the precise role of home BP monitoring in clinical practice.

Self-blood-pressure monitoring--a questionnaire study: response, requirement, training, support-group popularity and recommendations

The objective of this study was to survey hypertensive patients' response to, requirement for and training in self-blood pressure monitoring (SBPM). A total of 222 hypertensives were invited to complete a questionnaire even when not participating in the project. Questions supplied information on demographics, monitoring frequency, convenience of attending the surgery, monitor ownership and preference for and ease of self-monitoring. Comments supplied qualitative data. Training group questionnaires supplied similar data as well as SBPM data before and after training. Of 133 respondents, a higher educated, younger, wider age range wanted to participate (76; 57.2%) and tended to self-monitor. However, only an increase in further education (FE) was associated with an increased probability of participation and inclination to self-monitor in the multivariate analyses. A positive relationship exists between age and frequency in both groups. About a sixth of respondents own monitors and ownership is correlated to FE. Although most patients found it convenient to visit the surgery, the percentage finding it convenient was lower in patients attending training sessions than in the original survey, possibly indicating that independence is important for SBPM. Younger, higher-educated patients tended to self-monitor although FE was again the significant factor. Training increased preference for the idea of SBPM, prospective monitor ownership (64.8% of non-owners) and self-monitoring intention (76.1%). Patients found recording card listed cardiovascular disease (CVD) risks valuable and 69.6% (32) wanted to establish a support group. Comments and interviews indicated haphazard knowledge, routines and uncertainty about SBPM. A standardised procedure including patient assessment, SBPM protocol and lifestyle education is needed for SBPM to be successful.

Engineering and governmental challenge: 7-day/24-hour chronobiologic blood pressure and heart rate screening: Part I

This review provides evidence that the bioengineering community needs to develop cost-effective, fully unobtrusive, truly ambulatory instrumentation for the surveillance of blood pressure and heart rate. With available instrumentation, we document a disease risk syndrome, circadian blood pressure overswinging (CHAT, short for circadian hyper-amplitude-tension). Circadian hyper-amplitude-tension is defined as a week-long overall increase in the circadian amplitude or otherwise-measured circadian variability of blood pressure above a mapped threshold, corresponding to the upper 95% prediction limit of clinically healthy peers of the corresponding gender and age. A consistently reduced heart rate variability, gauged by a circadian standard deviation below the lower 5% prediction limit of peers of the corresponding gender and age, is an index of a separate yet additive major risk, a deficient heart rate variability (DHRV). The circadian amplitude, a measure of the extent of reproducible variability within a day, is obtained by linear curve-fitting, which yields added parameters: a midline-estimating statistic of rhythm, the MESOR (a time structure or chronome-adjusted mean), the circadian acrophase, a measure of timing of overall high values recurring in each cycle, and the amplitudes and acrophases of the 12-hour (and higher order) harmonic(s) of the circadian variation that, with the characteristics of the fundamental 24-hour component, describe the circadian waveform. The MESOR is a more precise and more accurate estimate of location than the arithmetic mean. The major risks associated with CHAT and/or DHRV have been documented by measurements of blood pressure and heart rate at 1-hour or shorter intervals for 48 hours on populations of several hundred people, but these risks are to be assessed in a 7-day/24-hour record in individuals before a physical examination, for the following reasons. (1) The average derived from an around-the-clock series of blood pressure measurements, computed as its MESOR, the proven etiopathogenetic factor of catastrophic vascular disease, can be above chronobiologic as well as World Health Organization limits for 5 days or longer and can be satisfactory for months thereafter, as validated by continued automatic monitoring. The MESOR can be interpreted in light of clock-hour-, gender-, and age-specified reference limits and thus can be more reliably estimated with a systematic account of major sources of variability than by casual time-unspecified spot checks (that conventionally are interpreted by a fixed and, thus, rhythm, gender-, and age-ignoring limit). With spot checks, in a diagnostically critical range of "borderline" blood pressures, an inference can depend on the clock-hour of the measurement, usually providing a diagnosis of normotension in the morning and of hypertension in the afternoon (for the same diurnally active, nocturnally resting patient!). Long-term treatment must not be based upon the possibility of an afternoon vs a morning appointment. Moreover, the conventional approach will necessarily miss cases of CHAT that are not accompanied by MESOR hypertension. (2) Circadian hyper-amplitude-tension indicates a greater risk for stroke than does an increase in the around-the-clock average blood pressure (above 130/80 mm Hg) or old age, whereas (3) CHAT can be asymptomatic, as can MESOR hyptertension. (4) Deficient heart rate variability, the fall below a threshold of the circadian standard deviation of heart rate, an entity in its own right, is also a chronome alteration of heart rate variability (CAHRV). Deficient heart rate variability can be present together with CHAT, doubling the relative risk of morbid events. In each case--either combined with CHAT or as an isolated CAHRV--a DHRV constitutes an independent diagnostic assessment provided as a dividend by current blood pressure monitors that should be kept in future instrumentation designs. CHAT and DHRV can be screened by systematic focus on variability, preferably by the use of automatic instrumentation and analyses, which are both available (affordably) for research in actual practice, in conjunction with the Halberg Chronobiology Center at the University of Minnesota.

Future developments in ambulatory blood pressure monitoring and self-blood pressure monitoring in clinical practice

A number of factors interact to promote the increased clinical use of both ambulatory blood pressure monitoring (ABPM) and self-blood pressure monitoring (SBPM). These include the phasing out of mercury, evidence of the unreliability of clinic measurements, technical advances in automated blood pressure measurement, increasing evidence that out-of-office measurements give the best risk assessment, and a gradual recognition by payers of the clinical utility of ABPM and SBPM. Both ABPM and SBPM have been endorsed by the two major guidelines for managing hypertensive patients (World Health Organization-International Society of Hypertension and Joint National Committee VI). The use of SBPM has grown enormously over the past few years, mostly because of direct sales to patients. Although SBPM may give a better estimate of the true blood pressure than clinic readings, there are concerns about the accuracy of the monitors in individual patients. The main clinical indication for ABPM is the diagnosis of white-coat hypertension. This requires the demonstration that the blood pressure is normal outside the clinic, which can be established using SBPM and confirmed by ABPM. Even though ABPM may save drug costs in patients with white-coat hypertension, its use may also lead to increased drug expenditure in others in whom it demonstrates suboptimal blood pressure control. SBPM has the potential to reduce the number of clinic visits and also to improve blood pressure control. The ultimate validation of both procedures will be whether they can prevent cardiovascular morbidity. There have been suggestions that a non-dipping pattern of nocturnal blood pressure may carry a bad prognosis, but this may apply only to certain disease end-points. The greater recognition of the relevance of dipping status should provide an additional stimulus to the growth of both procedures. It is anticipated that, in the future, hypertension will be managed by the 'virtual hypertension clinic', using ABPM for the initial diagnosis, and SBPM with electronic linkage between the patient and the health-care provider for maintenance and follow-up.

[Significant decline in blood pressure levels after 1996--fact or artefact?]

BACKGROUND

Since 1985, the National Health Screening Service has regularly offered men and women aged 40-42 years in all Norwegian counties except Oslo a cardiovascular disease risk factor screening. After 1996, a substantial decline in blood pressure levels was observed.

MATERIAL AND METHODS

Data from eight counties which were screened both in 1994-96 and 1997-99.

RESULTS

Mean systolic/diastolic blood pressure was 135.3/81.1 and 129.2/75.7 mm Hg in men and 126.1/75.9 and 119.4/70.3 mm Hg in women. The change in blood pressure is considered in relation to methodological aspects, such as blood pressure devices, situation, whether the measurements have been taken in ambulatory buses or indoors, and also in relation to life-style and other factors linked to blood pressure.

CONCLUSION

No reasonable explanation for the blood pressure decline has been traced.

Pressure for change: unresolved issues in blood pressure measurement

The use of mercury is likely to be prohibited within a few years and clinicians have not yet seriously considered what sphygmomanometers they will use, nor is authoritative advice available on alternative instruments. Doubts also surround the thorny question of cuff size. Most blood pressures are taken in assessing cardiovascular health, and serial consulting room measurements may not be the best way of doing this. What is the role of continuous ambulatory monitoring in routine care? What is the place of home monitoring by patients, now that accurate and easy-to-use electronic sphygmomanometers are available?

Fifteen years experience with finger arterial pressure monitoring: assessment of the technology

We review the Finapres technology, embodied in several TNO-prototypes and in the Ohmeda 2300 and 2300e Finapres NIBP. Finapres is an acronym for FINger Arterial PRESsure, the device delivers a continuous finger arterial pressure waveform. Many papers report on the accuracy of the device in comparison with intra-arterial or with noninvasive but intermittent blood pressure measurements. We compiled the results of 43 such papers and found systolic, diastolic and mean accuracies, in this order, ranging from -48 to 30 mmHg, from -20 to 18 mmHg, and from -13 to 25 mmHg. Weighted for the number of subjects included pooled accuracies were -0.8 (SD 11.9), -1.6 (8.3) and -1.6 (7.6) mmHg respectively. Subdividing the pooled group according to criteria such as reference blood pressure, place of application, and prototype or commercial device we found no significant differences in mean differences or SD. Measurement at the finger allows uninterrupted recordings of long duration. The transmission of the pressure pulse along the arm arteries, however, causes distortion of the pulse waveform and depression of the mean blood pressure level. These effects can be reduced by appropriate filtering, and upper arm 'return-to-flow' calibration to bring accuracy and precision within AAMI limits. For the assessment of beat-to-beat changes in blood pressure and assessment of blood pressure variability Finapres proved a reliable alternative for invasive measurements when mean and diastolic pressures are concerned. Differences in systolic pressure are larger and reach statistical significance but are not of clinical relevance. Finger arteries are affected by contraction and dilatation in relation to psychological and physical (heat, cold, blood loss, orthostasis) stress. Effects of these phenomena are reduced by the built-in Physiocal algorithm. However, full smooth muscle contraction should be avoided in the awake patient by comforting the patient, and covering the hand. Arterial state can be monitored by observing the behaviour of the Physiocal algorithm. We conclude that Finapres accuracy and precision usually suffice for reliable tracking of changes in blood pressure. Diagnostic accuracy may be achieved with future application of corrective measures.

Clinical significance and cost-effectiveness of 24-hour ambulatory blood pressure monitoring

Ambulatory blood pressure (BP) monitoring as an adjunct to casual/clinic BP measurements is currently used widely for the diagnosis and treatment of hypertension. It has been established that ambulatory BP monitoring is essential to confirm "white coat" hypertension, drug-resistant hypertension, duration of drug action, short-term BP variation, and nocturnal and on-the-job BP levels. It is estimated that approximately 10,000 ambulatory BP monitoring devices are currently used in Japan. That number would increase if 1) a standard algorithm with a theoretical basis to determine BP levels is introduced for ambulatory BP monitoring devices based on cuff-oscillometric method, 2) the reproducibility of ambulatory BP levels is confirmed, 3) reference values for evaluating ambulatory BP monitoring levels are established, and 4) the clinical significance and prognostic value of ambulatory BP monitoring is established. If such problems is settled, the use of ambulatory BP monitoring in the diagnosis and treatment of hypertension would be national health insurance and would improve the prognostic accuracy of evaluating hypertension as well as the cost-effectiveness of screening, diagnosis and treatment of hypertension.