Ambulatory blood pressure monitoring

The Role of Blood Pressure Load in Ambulatory Blood Pressure Monitoring in Adults: A Literature Review of Current Evidence

BACKGROUND

The blood pressure load (BPL) is commonly defined as the percentage of readings in a 24-h ambulatory blood pressure monitoring (ABPM) study above a certain threshold, usually the upper normal limit. While it has been studied since the 1990s, the benefits of using this index have not been clearly demonstrated in adults. We present the first review on the associations of BPL with target organ damage (TOD) and clinical outcomes in adults, the major determinants for its role and utility in blood pressure measurement. We emphasize studies which evaluated whether BPL has added benefit to the average blood pressure indices on ABPM in predicting adverse outcomes.

METHODS

PubMed search for all English language papers mentioning ABPM and BPL.

RESULTS

While multiple studies assessed this question, the cumulative sample size is small. Whereas the associations of BPL with various TODs are evident, the available literature fails to demonstrate a clear and consistent added value for the BPL over the average blood pressure indices.

CONCLUSIONS

There is a need for prospective studies evaluating the role of BPL in blood pressure measurement. The current literature does not provide sound support for the use of BPL in clinical decisions.

A new risk factor for predicting stroke in patients with atrial fibrillation: morning blood pressure surge

BACKGROUND

Stroke, the most feared complication in patients with atrial fibrillation (AF), is still an important cause of mortality and morbidity. In our study, we aimed to investigate the frequency of stroke and related parameters in patients with atrial fibrillation, for whom 24-h ambulatory blood pressure monitoring (ABPM) was performed.

METHOD

A total of 282 patients with permanent AF were included in this study. 24-h ABPM was performed in all patients. Morning blood pressure surge (MBPS) was defined as the difference between the mean SBP in the first 2 h after awakening and the lowest blood pressure (BP) at night. We evaluated parameters associated with stroke in patients with atrial fibrillation using univariate and multivariate Cox regression analysis.

RESULT

Patients were followed for 19 ± 9.3 months and 22 ischemic strokes were detected during the follow-up period. Also, strokes were significantly lower in atrial fibrillation patients with a dipper BP pattern, whereas strokes were significantly higher in atrial fibrillation patients with a reverse-dipper BP pattern. In multivariate analysis, a history of hypertension ( P  = 0.020), BP pattern ( P  < 0.001) and MBPS ( P  < 0.001) were found to be significantly related to stroke. MBPS levels >32.5 mmHg predicted stroke with a sensitivity of 77% and a specificity of 60% (AUC, 0.741; 95% CI, 0.647-0.834; P  < 0.001).

CONCLUSION

MBPS, BP pattern and presence of hypertension as an independent risk factor in predicting stroke in patients with atrial fibrillation. The reduction of the MBPS may be a new therapeutic target for preventing stroke.

The Health Effects of 72 Hours of Simulated Wind Turbine Infrasound: A Double-Blind Randomized Crossover Study in Noise-Sensitive, Healthy Adults

BACKGROUND

Large electricity-generating wind turbines emit both audible sound and inaudible infrasound at very low frequencies that are outside of the normal human range of hearing. Sufferers of wind turbine syndrome (WTS) have attributed their ill-health and particularly their sleep disturbance to the signature pattern of infrasound. Critics have argued that these symptoms are psychological in origin and are attributable to nocebo effects.

OBJECTIVES

We aimed to test the effects of 72 h of infrasound (1.6-20 Hz at a sound level of ∼90 dB pk re 20μPa, simulating a wind turbine infrasound signature) exposure on human physiology, particularly sleep.

METHODS

We conducted a randomized double-blind triple-arm crossover laboratory-based study of 72 h exposure with a >10-d washout conducted in a noise-insulated sleep laboratory in the style of a studio apartment. The exposures were infrasound (∼90  dB pk), sham infrasound (same speakers not generating infrasound), and traffic noise exposure [active control; at a sound pressure level of 40-50 dB LAeq,night and 70 dB LAFmax transient maxima, night (2200 to 0700 hours)]. The following physiological and psychological measures and systems were tested for their sensitivity to infrasound: wake after sleep onset (WASO; primary outcome) and other measures of sleep physiology, wake electroencephalography, WTS symptoms, cardiovascular physiology, and neurobehavioral performance.

RESULTS

We randomized 37 noise-sensitive but otherwise healthy adults (18-72 years of age; 51% female) into the study before a COVID19-related public health order forced the study to close. WASO was not affected by infrasound compared with sham infrasound (-1.36 min; 95% CI: -6.60, 3.88, p=0.60) but was worsened by the active control traffic exposure compared with sham by 6.07 min (95% CI: 0.75, 11.39, p=0.02). Infrasound did not worsen any subjective or objective measures used.

DISCUSSION

Our findings did not support the idea that infrasound causes WTS. High level, but inaudible, infrasound did not appear to perturb any physiological or psychological measure tested in these study participants. https://doi.org/10.1289/EHP10757.

Day and night blood pressure variability among older persons in South-Western Nigeria

BACKGROUND

Hypertension is the largest contributor to the global burden of disease. Emerging risk factors for cardiovascular disease include blood pressure variability (BPV), but evidence on BPV is lacking among older Nigerians. We reported BPV in a cohort of older persons at the University College Hospital (UCH), Ibadan.

METHODS

We conducted a retrospective cohort study of respondents aged >50 years within the Ibadan Ambulatory Blood Pressure Registry at the UCH, Ibadan, Nigeria. Socio-demographic characteristics, lifestyle habits and anthropometric measurements were obtained.

RESULTS

Among 639 respondents, 332 (52.0%) were female. The blood pressure (BP) variables were strongly associated with age. Compared with younger age groups, mean diastolic BP (DBP) was less at an older age, whereas mean pulse pressure was greater. During the wake-up and sleep periods, mean DBP and mean arterial BP were less with each increasing age category, whereas mean pulse pressure was larger with each increasing age category. BP dipping, systolic, diastolic and mean arterial BP decreased with age. Overall, timed BPV increased significantly with increasing age. The prevalence of white-coat hypertension was greater among older participants than younger participants. Most respondents in the 50-59 years' age group were non-dippers (55.8%), whereas 33.7% of older respondents were reverse-dippers.

CONCLUSION

Older persons experienced a greater abnormal circadian blood variation and greater BPV than younger people. In Nigeria, follow-up data are needed to determine the prognostic significance of these data in this population.

Effects of cycling bouts performed with different intensities and amounts of energy expended on central pressure and pulse wave reflection in normotensive and hypertensive men

OBJECTIVE

This study investigated pulse wave analysis in normotensive and hypertensive men after cycling bouts with different intensities and amounts of energy expended.

METHODS

Twenty-four men were assigned into normotensive (n = 14; age: 40.7 ± 2.8 years; 24-h ambulatory SBP/DBP:121 ± 2/74 ± 1 mmHg) and hypertensive (n = 10; age: 39.2 ± 2.3 years; 24-h ambulatory SBP/DBP:139 ± 3/86 ± 2 mmHg) groups. Participants undertook a maximal cardiopulmonary exercise test, a nonexercise control session (CTL) and three cycling bouts [two prolonged bouts expending 300 kcal at 50% (i.e. P-MOD) and 70% (i.e. P-VIG) oxygen uptake reserve (VO2R) and one short bout expending 150 kcal at 50% VO2R (i.e. S-MOD)] performed in a randomized order. Central SBP (cSBP), pulse pressure (cPP), augmentation pressure, augmentation index (AIx), heart rate (HR) and AIx adjusted for HR (AIx@75) were determined 10 min before, and 30- and 70-min postintervention.

RESULTS

Compared to CTL, only the P-VIG changed the cSBP [70-min (Δ -11.7 mmHg)], cPP [70-min (Δ:-7.4 mmHg)], augmentation pressure [30-min (Δ:-5.7 mmHg); 70-min (Δ:-7.3 mmHg)], AIx [30-min (Δ:-15.3 %); 70-min (Δ:-16.4 %)], AIx@75 [30-min (Δ:-12.8 %); 70-min (Δ:-13.9 %)] and HR [70-min (Δ: 9.9 bpm)] in the hypertensive group. However, all exercise bouts mitigated the increased cSBP responses post-CTL in the hypertensive group.

CONCLUSION

The present study provides evidence that vigorous-intensity aerobic exercise reduces acute central pressure and pulse wave reflection in hypertensive men.

Development of intelligent healthcare system based on ambulatory blood pressure measuring device

Currently, the market size of blood pressure monitors both in domestic and overseas is gradually increasing due to the increase in hypertension patients resulting from aging population. In addition, the necessity of developing systems and devices for the healthcare of hypertension patients is also increasing. Moreover, the determination of health normality in respect to the management of hypertension patients is possible, but it is essentially important to incorporate preventive healthcare. Thus, further studies on deep learning-based prediction technology using previous data are needed. This paper proposes the development of an intelligent healthcare management system that can help to manage the health of hypertensive patients. The system includes a wrist-worn ambulatory blood pressure monitoring device that can analyze the normality of measured blood pressures. The performance evaluation results of the proposed system verified the reliability of data acquisition as compared with the existing equipment as well as the efficiency of the intelligent healthcare system.

Disruptive, Soft, Wearable Sensors

The wearable industry is on the rise, with a myriad of technical applications ranging from real-time health monitoring, the Internet of Things, and robotics, to name but a few. However, there is a saying "wearable is not wearable" because the current market-available wearable sensors are largely bulky and rigid, leading to uncomfortable wearing experience, motion artefacts, and poor data accuracy. This has aroused a world-wide intensive research quest for novel materials, with the aim of fabricating next-generation ultra-lightweight and soft wearable devices. Such disruptive second-skin-like biosensing technologies may enable a paradigm shift from current wearable 1.0 to future wearable 2.0 products. Here, the state-of-the-art progress made in the key phases for future wearable technology, namely, wear → sense → communicate → analyze → interpret → decide, is summarized. Without a doubt, materials innovation is the key, which is the main focus of the discussion. In addition, emphasis is also given to wearable energy, multicomponent integration, and wireless communication.

Guidelines for blood pressure measurement: development over 30 years

In the last 2 decades, several scientific societies have published specific guidelines for blood pressure (BP) measurement, providing detailed recommendations for office, home, and ambulatory BP monitoring. These documents typically provided strong support for using out-of-office BP monitoring (ambulatory and home). More recently, several organizations recommended out-of-office BP evaluation as a primary method for diagnosing hypertension and for treatment titration, with office BP regarded as a screening method. Efforts should now be directed towards making ambulatory and home BP monitoring readily available in primary care and ensuring that such measurements are obtained by following current guidelines. Moreover, it should be mandatory for all published clinical research papers on hypertension to provide details on the methodology of the BP measurement.

Microvascular narrowing and BP monitoring: A single centre observational study

Introduction

Half of all hypertensive individuals have inadequately-controlled BP because monitoring methods are ineffective. This single centre study examined consecutive subjects undergoing 24 hour BP measurements for clinic and ambulatory BP levels, and for end-organ damage (retinal microvascular abnormalities and left ventricular hypertrophy, LVH, > 1.1 cm). Retinal images were graded for microvascular retinopathy (Wong and Mitchell classification), and vessel calibre using a semiautomated method. Features were compared using chi-squared, Fisher’s exact or the student’s t test.

Methods

One hundred and thirty-one individuals (59 male, 45.0%, mean age 61.7 ± 14.5 years) were studied. Ninety-nine (76.2%) had a clinic BP ≥ 140/90 mm Hg, 84 (64.6%) had a mean awake systolic BP ≥ 135 mm Hg, 100 (76.9%) had a mean sleeping systolic BP ≥ 120 mm Hg, and 100 (76.2%) had abnormal nocturnal BP dipping patterns. Sixty-nine individuals had undergone echocardiography and 23 (33.3%) had LVH.

Results

All participants had a mild (88.5%) or moderate (11.5%) microvascular retinopathy. Moderate microvascular retinopathy was found in 86.7% of those with a mean awake systolic BP ≥135 mm Hg (p = 0.058) but was not associated with other abnormal BP measurements, abnormal dipping patterns or LVH. However retinal arteriole calibre was reduced in subjects with a mean 24 hour awake systolic BP ≥ 135 mm Hg (p = 0.05). Retinal arteriole calibre was smaller in subjects with LVH (128.1 ± 13.5 μm compared with 137.6 ± 14.1 μm in normals, p = 0.014). Venular calibre was also less in subjects with LVH (185.4 ± 24.6 μm compared with 203.0 ± 27.2 μm in normals, p = 0.016). Arteriole narrowing predicted an increased risk of LVH (AUC 0.69, 95%CI 0.55 to 0.83) that was comparable with 24 hour systolic BP ≥130 mm Hg (AUC 0.68, 95%CI 0.53 to 0.82) and mean awake systolic BP ≥135 mm Hg (AUC 0.68, 95%CI 0.54 to 0.83).

Conclusions

This study suggests that retinal arteriole narrowing may be equally accurate in predicting LVH as any clinic or ambulatory BP measurement. The convenience and accuracy of microvascular calibre measurement mean that it should be investigated further for a role in routine hypertension assessment and monitoring.

Home Blood Pressure Monitoring Has Similar Effects on Office Blood Pressure and Medication Compliance as Usual Care

Background

Home blood pressure monitoring is recommended to achieve controlled blood pressure. This study evaluated home blood pressure monitoring-improvement of office blood pressure control and treatment compliance among hypertensive patients.

Methods

A randomized controlled trial was conducted from December 2014 to April 2015. The home blood pressure monitoring group used an automatic blood pressure device along with standard hypertension outpatient care. Patients were seen at baseline and after 2 months. Medication adherence was measured using a novel validated Medication Adherence Scale (MAS) questionnaire. Office blood pressure and MAS were recorded at both visits. The primary outcomes included evaluation of mean office blood pressure and MAS within groups and between groups at baseline and after 2 months.

Results

Mean changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) and MAS differed significantly within groups. The home blood pressure monitoring group showed greater mean changes (SBP 17.6 mm Hg, DBP 9.5 mm Hg, MAS 1.5 vs. SBP 14.3 mm Hg, DBP 6.4 mm Hg, MAS 1.3), while between group comparisons showed no significant differences across all variables. The adjusted mean difference for mean SBP was 4.74 (95% confidence interval [CI], -0.65 to 10.13 mm Hg; P=0.084), mean DBP was 1.41 (95% CI, -2.01 to 4.82 mm Hg; P=0.415), and mean MAS was 0.05 (95% CI, -0.29 to 0.40 mm Hg; P=0.768).

Conclusion

Short-term home blood pressure monitoring significantly reduced office blood pressure and improved medication adherence, albeit similarly to standard care.

The Association between Indoor Air Quality and Adult Blood Pressure Levels in a High-Income Setting

Background: Indoor air pollution is still considered one of the leading causes of morbidity and mortality worldwide. We aimed to investigate the potential association between indoor particulate matter (PM) and fasting clinic blood pressure in adult Australians. Methods: Sixty-three participants residing within the Perth metropolitan area were studied. Participants were aged between 18 and 65 years and free of major medical conditions. We conducted 24-h monitoring of residential PM concentrations, including the size fractions PM1, PM2.5, PM4, and PM10. All participants attended a clinical assessment at Curtin University following a 10–12 h overnight fast. Results: In this study we found that PM1 and PM2.5 were significantly associated with heart rate: a one interquartile range (IQR) increase in PM1 or PM2.5 was associated with a 4–6 beats per minute (bpm) increase in heart rate. Both PM10 and total PM exposure had a significant impact on systolic blood pressure (SBP): a one IQR increase in PM10 and total PM were associated with a 10 mmHg (95% CI: 0.77–20.05) and 12 mmHg (2.28–22.43 mmHg) increase in SBP, respectively. Conclusion: The study findings provide additional support to the thesis that indoor air pollution is an important modifiable factor in the risk of hypertension.

Ambulatory blood pressure monitoring in daily practice

Ambulatory blood pressure monitoring is a useful diagnostic tool that still underutilized by community physicians. It is a cost effective, diagnostic and prognostic tool that had been emphasized by the guidelines.

Habitual exercise decreases systolic blood pressure during low-intensity resistance exercise in healthy middle-aged and older individuals

Since aerobic exercise (e.g., walking) and resistance exercise (e.g., lifting objects and mopping) are both parts of the activities of daily living, an exaggerated elevation in systolic blood pressure (SBP) during aerobic and resistance exercise is an early marker of cardiovascular disease. This study investigated the effects of habitual exercise on SBP during low-intensity resistance exercise using both cross-sectional and interventional approaches. First, in 57 normotensive women (61.9 ± 1.0 yr of age), daily physical activity level, as assessed by triaxial accelerometry, was correlated with SBP during resistance exercise at 20 and 40% of the 1 repetition maximum ( r = −0.408 and r = −0.348, respectively). Maximal oxygen uptake was correlated with SBP during exercise at 20% ( r = −0.385) and 40% ( r = −0.457). Physical activity level or maximal oxygen uptake was identified as a predictor of SBP during the exercise in stepwise regression analysis, independent of SBP at rest and other factors ( R2= 0.729–0.781). Second, 66 men and women (64.6 ± 0.9 yr of age) participated in a 6-wk intervention as a part of the training (walking, 4.3 ± 0.3 days/wk, 55.6 ± 4.1 min/day, 70.7 ± 1.2% of maximal heart rate) or control group. SBP during resistance exercise in the training group decreased after the intervention (before vs. after: 20%, 143 ± 4 vs. 128 ± 4 mmHg; and 40%, 148 ± 5 vs. 134 ± 4 mmHg). In the control group, there were no significant differences in SBP before and after the intervention. SBP during resistance exercise after the intervention was lower in the training group relative to the control group. These results suggest that habitual exercise decreases SBP during low-intensity resistance exercise.

Secondary Stroke Prevention: Improving Diagnosis and Management with Newer Technologies

Treatment of hypertension, diabetes, high cholesterol, smoking cessation, and healthy lifestyle have all contributed to the decline in the incidence of vascular disease over the last several decades. Patients who suffer an acute stroke are at a high risk for recurrence. Introduction of newer technologies and their wider use allows for better identification of patients in whom the risk of recurrence following an acute stroke may be very high. Traditionally, the major focus for diagnosis and management has focused on patient history, examination, imaging for carotid stenosis/occlusion, and detection of AF and paroxysmal AF (PAF) with 24-48 h cardiac monitoring. This review focuses on the usefulness of three newer investigative tools that are becoming widely available and lead to better prevention. Continuous ambulatory blood pressure measurements for 24 h or longer and 3D Doppler measures of the carotid arteries provide key useful information on the state of vascular health and enhance our ability to monitor the response to preventive therapies. Furthermore, the detection of PAF can be significantly improved with prolonged cardiac monitoring for 3 weeks or longer, enabling the initiation of appropriate prevention therapy. This review will focus on the potential impact and importance of these emerging technologies on the prevention of recurrent stroke in high-risk patients.

Untreated newly diagnosed essential hypertension is associated with nonalcoholic fatty liver disease in a population of a hypertensive center

Purpose

Recent studies have demonstrated that hypertension (HTN) is associated with nonalcoholic fatty liver disease (NAFLD) in treated hypertensive patients. The aim of this study was to investigate the association between newly diagnosed essential HTN and NAFLD in untreated hypertensive patients.

Patients and methods

A consecutive series of 240 subjects (143 hypertensives and 97 normotensives), aged 30–80 years, without diabetes mellitus were enrolled in the study. Subjects with 24-hour systolic blood pressure (SBP) values ≥130 mmHg and/or diastolic BP values ≥80 mmHg were defined as hypertensives. NAFLD was defined as the presence of liver hyperechogenicity on ultrasound.

Results

Body mass index (P=0.002) and essential HTN (P=0.016) were independently associated with NAFLD in the multivariate logistic regression model. Furthermore, the multivariate analysis revealed that morning SBP (P=0.044) was independently associated with NAFLD.

Conclusion

Untreated, newly diagnosed essential HTN is independently associated with NAFLD. Ambulatory BP monitoring could be used for the diagnosis of essential HTN in patients with NAFLD.

Implementation of simple telehealth to manage hypertension in general practice: a service evaluation

BACKGROUND

Hypertension is common and conveys significant risk of morbidity and mortality. However, inadequate control of hypertension is common. Following a successful local use of a simple telehealth intervention ('Florence') for the diagnosis and management of hypertension, the Advice & Interactive Messaging (AIM) for Health simple telehealth programme was launched across England in March 2013. Four protocols were developed to diagnose and monitor blood pressure (BP). The aim of this service evaluation was to identify the extent to which predefined service outcomes, regarding ascertainment of a diagnosis of hypertension, and achievement of hypertension control, were met for the hypertension protocols.

METHODS

Patients with opportunistic raised BP in general practice or diagnosed hypertension were selected by their usual primary care providers to register onto diagnostic or monitoring hypertension protocols, respectively. Florence sent patients prompts via text messaging to submit readings, educational messages and user satisfaction questions. Patient responses were stored on Florence for review by their primary care health providers. This service evaluation used data from 2963 patients from general practices across England registered onto one of four AIM hypertension protocols from inception to January 2014. Data were extracted from Florence and underwent descriptive analysis.

RESULTS

1166/1468 (79 %) patients were eligible to have a diagnosis of hypertension confirmed/refuted, of which 740 (63 %) had a mean BP in the hypertensive range from one week's readings. BP control was achieved by only 5-22 % of 1495 patients signed up to one of the three monitoring protocols. Patient engagement with the monitoring protocols was initially good but reduced over time.

CONCLUSIONS

Although simple telehealth may be an acceptable tool for diagnosing and monitoring hypertension among responding patient users, and can have a useful role in diagnosis of hypertension (particularly if ambulatory blood pressure monitoring (ABPM) is not possible or is declined), problems were identified. Reduced patient engagement over longer periods and acceptance of suboptimal BP control among patients on monitoring protocols need to be urgently addressed. Empirical work is required to identify barriers to achieving BP control among hypertensive patients using simple telehealth and, consequently, services be developed to address these issues.

Tissue-informative mechanism for wearable non-invasive continuous blood pressure monitoring

Accurate continuous direct measurement of the blood pressure is currently available thru direct invasive methods via intravascular needles, and is mostly limited to use during surgical procedures or in the intensive care unit (ICU). Non-invasive methods that are mostly based on auscultation or cuff oscillometric principles do provide relatively accurate measurement of blood pressure. However, they mostly involve physical inconveniences such as pressure or stress on the human body. Here, we introduce a new non-invasive mechanism of tissue-informative measurement, where an experimental phenomenon called subcutaneous tissue pressure equilibrium is revealed and related for application in detection of absolute blood pressure. A prototype was experimentally verified to provide an absolute blood pressure measurement by wearing a watch-type measurement module that does not cause any discomfort. This work is supposed to contribute remarkably to the advancement of continuous non-invasive mobile devices for 24-7 daily-life ambulatory blood-pressure monitoring.

Clinical significance of home blood pressure measurements for the prevention and management of high blood pressure

1. Ambulatory blood pressure (ABP) monitoring (M) provides BP information at many points on any particular day during unrestricted routine daily activities, whereas home blood pressure (HBP) monitoring provides a lot of BP information obtained under fixed times and conditions over a long period of time, thus mean values of HBP provide high reproducibility, and thus an overall superiority compared with ABP.  2. HBP is at least equally or better able than ABP to predict hypertensive target organ damage and prognosis of cardiovascular disease.  3. HBPM allows for ongoing disease monitoring by patients, improves adherence to antihypertensive treatment, and can provide health-care providers with timely clinical data and direct and immediate feedback regarding diagnosis and treatment of hypertension.  4. HBPM provides BP information in relation to time; that is, BP in the morning, in the evening and at night during sleep, and it is an essential tool for the diagnosis of white-coat and masked hypertension.  5. HBPM yields minimal alerting affects and no or minimal placebo effect, and can therefore distinguish small, but significant, serial changes in BP. It is thus the most practical method for monitoring BP in the day-to-day management of hypertension. 6. The superiority of HBPM over ABPM and clinic BPM is apparent from almost all practical and clinical research perspectives.

A blood pressure monitoring method for stroke management

Blood pressure is one important risk factor for stroke prognosis. Therefore, continuous monitoring of blood pressure is crucial for preventing and predicting stroke. However, current blood pressure devices are mainly air-cuff based, which only can provide measurements intermittently. This study proposed a new blood pressure estimation method based on the pulse transit time to realize continuous monitoring. The proposed method integrated a linear model with a compensation algorithm. A calibration method was further developed to guarantee that the model was personalized for individuals. Variation and variability of pulse transit time were introduced to construct the compensation algorithm in the model. The proposed method was validated by the data collected from 30 healthy subjects, aged from 23 to 25 years old. By comparing the estimated value to the measurement from an oscillometry, the result showed that the mean error of the estimated blood pressure was −0.2 ± 2.4 mmHg and 0.5 ± 3.9 mmHg for systolic and diastolic blood pressure, respectively. In addition, the estimation performance of the proposed model is better than the linear model, especially for the diastolic blood pressure. The results indicate that the proposed method has promising potential to realize continuous blood pressure measurement.

Monitoring technology for the elderly patient

In view of the current demographic change in the aging population and its impact on changing the health system towards community care, this review focuses on monitoring technology for elderly patients. In particular, the focus is on wearable monitoring technology and its integration into telehealth systems. In review of the available commercial wearable monitoring technologies, their form factor, sensing methods and application for the purpose of monitoring elderly patients for ongoing care are discussed. At the same time, advances in research regarding how to overcome the limitations of commercial wearable monitoring devices are reviewed. Issues of usability, functionality, human interaction and social factors, and ethical considerations in the application of wearable monitoring and telehealth technologies for elderly patients are outlined. Some of the initiatives taken to address these issues are also discussed and some suggestions are made. Finally, the review looks at the anticipated benefits of the application of wearable monitoring and telehealth technologies from an elderly patient, clinician or carer and healthcare system point of view. Expert opinion of what strategies need to be used to enhance the use and uptake of these technologies and what future directions are anticipated are expressed. In conclusion, available wearable monitoring technologies and its integration into teleheath systems are currently limited for application on elderly patients. There are many issues of standardization, design and ethical considerations that need to be addressed before advances can be made with these technologies so that these patients can be remotely monitored and provided with a better quality of care.

Mobile personal health system for ambulatory blood pressure monitoring

The ARVmobile v1.0 is a multiplatform mobile personal health monitor (PHM) application for ambulatory blood pressure (ABP) monitoring that has the potential to aid in the acquisition and analysis of detailed profile of ABP and heart rate (HR), improve the early detection and intervention of hypertension, and detect potential abnormal BP and HR levels for timely medical feedback. The PHM system consisted of ABP sensor to detect BP and HR signals and smartphone as receiver to collect the transmitted digital data and process them to provide immediate personalized information to the user. Android and Blackberry platforms were developed to detect and alert of potential abnormal values, offer friendly graphical user interface for elderly people, and provide feedback to professional healthcare providers via e-mail. ABP data were obtained from twenty-one healthy individuals (>51 years) to test the utility of the PHM application. The ARVmobile v1.0 was able to reliably receive and process the ABP readings from the volunteers. The preliminary results demonstrate that the ARVmobile 1.0 application could be used to perform a detailed profile of ABP and HR in an ordinary daily life environment, bedsides of estimating potential diagnostic thresholds of abnormal BP variability measured as average real variability.

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.

The Fremantle Primary Prevention Study: a multicentre randomised trial of absolute cardiovascular risk reduction

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of global mortality. Risk factor management in clinical practice often relies on relative risk modification rather than the more appropriate absolute risk assessment.

AIM

To determine whether patients receiving more-frequently designated GP visits had increased benefit in terms of their absolute CVD risk assessment, as compared with patients in receipt of their usual GP care.

DESIGN AND SETTING

Prospective, open, pragmatic block randomised study in a 1:1 group allocation ratio in three Western Australian general practices.

METHOD

A convenience sample (n = 1200) of patients aged 40-80 years were randomised to 3-monthly GP visits (five in total for the intensive) or usual GP care (two in total for the opportunistic), with 12 months' follow-up. The main outcome was absolute CVD risk scores based on the New Zealand Cardiovascular Risk Calculator. Others outcome measures were weight, height, waist circumference, blood pressure, and fasting blood lipids and glucose.

RESULTS

There were 600 patients per group at baseline. At 12 months' analysis there were 543 in the intensive group and 569 in the opportunistic group. Mean (standard deviation [SD]) absolute CVD risk reduced significantly between baseline and 12 months in the intensive group (6.28% [5.11] to 6.10% [4.94]) but not in the opportunistic group (6.27% [5.10] to 6.24% [5.38]). There was a significant reduction between baseline and 12 months in mean (SD) total cholesterol (5.28 mmol/l [0.94] to 5.08 mmol/l [0.96]); low-density lipoprotein cholesterol (3.08 mmol/l [0.87] to 2.95 mmol/l [0.89]); triglyceride (1.45 mmol/l [0.86] to 1.36 mmol/l [0.84]); and in mean (SD) waist circumference in men (98.74 cm [10.70] to 97.13 cm [10.20]) and females (90.64 cm [14.62] to 88.96 cm [14.00]) in the intensive group.

CONCLUSION

A targeted approach using absolute risk calculators can be used in primary care to modify global CVD risk assessment.

Measurement of blood pressure using an arterial pulsimeter equipped with a Hall device

To measure precise blood pressure (BP) and pulse rate without using a cuff, we have developed an arterial pulsimeter consisting of a small, portable apparatus incorporating a Hall device. Regression analysis of the pulse wave measured during testing of the arterial pulsimeter was conducted using two equations of the BP algorithm. The estimated values of BP obtained by the cuffless arterial pulsimeter over 5 s were compared with values obtained using electronic or liquid mercury BP meters. The standard deviation between the estimated values and the measured values for systolic and diastolic BP were 8.3 and 4.9, respectively, which are close to the range of values of the BP International Standard. Detailed analysis of the pulse wave measured by the cuffless radial artery pulsimeter by detecting changes in the magnetic field can be used to develop a new diagnostic algorithm for BP, which can be applied to new medical apparatus such as the radial artery pulsimeter.

Nonmotor symptoms in Parkinson’s disease: the dark side of the moon

Nonmotor symptoms may appear during the course of Parkinson’s disease, complicating the advanced phase in particular, but are also common in the premotor phase of Parkinson’s disease. The appearance of nonmotor manifestations represents a milestone, determining a worse prognosis and lower quality of life; however, they are often misdiagnosed and untreated. The spectrum of nonmotor symptoms encompasses mood disorders, psychosis, dementia, sleep disorders, impulse-control disorders and autonomic dysfunctions. This article describes these nonmotor symptoms and their management.

Adult outcome of extremely preterm infants

Survival rates for extremely preterm (<28 weeks' gestational age) infants have increased and are approaching 3 in 4 with the advent of modern perinatal and neonatal intensive care. In contrast with some children with chronic diseases such as cystic fibrosis, most survivors of extreme prematurity have no ongoing health issues. However, as a group, they do have higher rates of adverse health outcomes, and more of them will present to pediatricians over time and, ultimately, to adult physicians as they grow older. Pediatricians can aid the transition to adult health care by being aware of the nutritional, cardiovascular, respiratory, motor, cognitive, psychiatric, and functional outcomes into adulthood of survivors of extreme prematurity.

Definition of ambulatory blood pressure targets for diagnosis and treatment of hypertension in relation to clinic blood pressure: prospective cohort study

BACKGROUND

Twenty-four hour ambulatory blood pressure thresholds have been defined for the diagnosis of mild hypertension but not for its treatment or for other blood pressure thresholds used in the diagnosis of moderate to severe hypertension. We aimed to derive age and sex related ambulatory blood pressure equivalents to clinic blood pressure thresholds for diagnosis and treatment of hypertension.

METHODS

We collated 24 hour ambulatory blood pressure data, recorded with validated devices, from 11 centres across six Australian states (n=8575). We used least product regression to assess the relation between these measurements and clinic blood pressure measured by trained staff and in a smaller cohort by doctors (n=1693).

RESULTS

Mean age of participants was 56 years (SD 15) with mean body mass index 28.9 (5.5) and mean clinic systolic/diastolic blood pressure 142/82 mm Hg (19/12); 4626 (54%) were women. Average clinic measurements by trained staff were 6/3 mm Hg higher than daytime ambulatory blood pressure and 10/5 mm Hg higher than 24 hour blood pressure, but 9/7 mm Hg lower than clinic values measured by doctors. Daytime ambulatory equivalents derived from trained staff clinic measurements were 4/3 mm Hg less than the 140/90 mm Hg clinic threshold (lower limit of grade 1 hypertension), 2/2 mm Hg less than the 130/80 mm Hg threshold (target upper limit for patients with associated conditions), and 1/1 mm Hg less than the 125/75 mm Hg threshold. Equivalents were 1/2 mm Hg lower for women and 3/1 mm Hg lower in older people compared with the combined group.

CONCLUSIONS

Our study provides daytime ambulatory blood pressure thresholds that are slightly lower than equivalent clinic values. Clinic blood pressure measurements taken by doctors were considerably higher than those taken by trained staff and therefore gave inappropriate estimates of ambulatory thresholds. These results provide a framework for the diagnosis and management of hypertension using ambulatory blood pressure values.

Evaluation scale to assess the accuracy of cuff-less blood pressure measuring devices

OBJECTIVE

The call for early detection of hypertension and cardiac events creates a heavy demand for devices that can be used for blood pressure (BP) monitoring at home and in ambulatory settings. An emerging type of BP monitors without an occluding cuff has drawn great attentions for this application because it is comfortable and capable of providing continuous readings. For the development the cuff-less devices, it is crucial for the clinicians and engineers to joint efforts in establishing an evaluation standard.

METHODS

This study attempts to contribute to its initiation in two ways. First, a new distribution model for measurement differences between the test device and the reference was proposed. We verified the model using evaluation results from 40 devices, of which 80% of the American Association for the Advancement of Medical Instrumentation and British Hypertension Society reporting results were in agreement, as compared with 50%, if the original normal model was used. We further tested a cuff-less device on 85 patients for 999 datasets and found that the differences between the proposed distribution and that of the device were nonsignificant for systolic BP measurements (Kolmogorov-Smirnov = 0.036, P = 0.15). Second, some evaluation scales were studied for their capability to assess the accuracy of cuff-less devices. For mean absolute difference, a map was developed to relate it with the criteria of American Association for the Advancement of Medical Instrumentation, British Hypertension Society, and European Society of Hypertension protocols, on the basis of the proposed distribution model; for mean absolute percentage difference, it is prominent in evaluating devices that have measurement errors often increasing with BP, which is an issue has not been fully explored in existing standards.

CONCLUSION

This study focused on the statistical aspect of establishing standard to assess the accuracy of cuff-less BP measuring devices. The results of our study on the validation reports of various cuff-based devices and an experimental study on a cuff-less device showed that the t4 distribution is better than the normal distribution in portraying the underlying error distribution of both kinds of devices. Moreover, based on both the theoretical and experimental studies, mean absolute difference or mean absolute percentage difference is recommended as continuous scale to assess the accuracy of cuff-less devices for their own distinctive advantages.

A protocol design for evaluation of wearable cuff-less blood pressure measuring devices

This paper proposes one of the unique requirements in the validation protocol of the IEEE P1708 standard in assessing wearable cuff-less blood pressure (BP) measuring devices. Based on principles that are different from that of the conventional cuff-based devices, the cuff-less BP measurement approaches often require an individual calibration procedure. In this study, we used data from an experiment carried out on 28 subjects with a total of 139 sets of BP measurements as an example to show that breakdown of the performance evaluation of cuff-less devices according to the change of BP from the point of calibration is crucial for understanding and interpreting the overall accuracy of the device.

Ambulatory blood pressure and physical activity in heart failure

This observational study used repeated measures over 24 hr to investigate ambulatory blood pressure (BP) and physical activity (PA) profiles in community-based individuals with heart failure (HF). The aims were to (a) compare BP dipping and PA between two groups of HF patients with different functional statuses, and (b) determine whether the strength of the association between ambulatory BP and PA varies by functional status in HF. Ambulatory BP was measured every 30 min with a SpaceLabs 90207; a Basic Motionlogger actigraph was used to measure PA minute-by-minute. Fifty-six participants (54% female, age 66.96 + or - 12.35 years) completed data collection. Functional status was based on New York Heart Association (NYHA) ratings. Twenty-seven patients had no limitation of PA (NYHA Class I HF), whereas 29 had some limitation of PA but no discomfort at rest (NYHA Class II or III HF). Patients with Class I HF had a significantly greater degree of BP dipping than those with Class II/III HF after controlling for left ventricular ejection fraction. In a mixed-model analysis, PA was significantly related to ambulatory systolic and diastolic BP and mean arterial pressure. The strength of the association between PA and BP was not significantly different for the two groups of patients. These findings demonstrate differences between Class I and Class II/II HF in BP dipping status and ambulatory BP but not PA. Longitudinal research is recommended to improve understanding of the influence of disease progression on changes in 24-hr PA and BP profiles of patients with HF.

Call to action on use and reimbursement for home blood pressure monitoring: a joint scientific statement from the American Heart Association, American Society of Hypertension, and Preventive Cardiovascular Nurses Association

Home blood pressure monitoring (HBPM) overcomes many of the limitations of traditional office blood pressure (BP) measurement and is both cheaper and easier to perform than ambulatory BP monitoring. Monitors that use the oscillometric method are currently available that are accurate, reliable, easy to use, and relatively inexpensive. An increasing number of patients are using them regularly to check their BP at home, but although this has been endorsed by national and international guidelines, detailed recommendations for their use have been lacking. There is a rapidly growing literature showing that measurements taken by patients at home are often lower than readings taken in the office and closer to the average BP recorded by 24-hour ambulatory monitors, which is the BP that best predicts cardiovascular risk. Because of the larger numbers of readings that can be taken by HBPM than in the office and the elimination of the white-coat effect (the increase of BP during an office visit), home readings are more reproducible than office readings and show better correlations with measures of target organ damage. In addition, prospective studies that have used multiple home readings to express the true BP have found that home BP predicts risk better than office BP (Class IIa; Level of Evidence A). This call-to-action article makes the following recommendations: (1) It is recommended that HBPM should become a routine component of BP measurement in the majority of patients with known or suspected hypertension; (2) Patients should be advised to purchase oscillometric monitors that measure BP on the upper arm with an appropriate cuff size and that have been shown to be accurate according to standard international protocols. They should be shown how to use them by their healthcare providers; (3) Two to 3 readings should be taken while the subject is resting in the seated position, both in the morning and at night, over a period of 1 week. A total of >/=12 readings are recommended for making clinical decisions; (4) HBPM is indicated in patients with newly diagnosed or suspected hypertension, in whom it may distinguish between white-coat and sustained hypertension. If the results are equivocal, ambulatory BP monitoring may help to establish the diagnosis; (5) In patients with prehypertension, HBPM may be useful for detecting masked hypertension; (6) HBPM is recommended for evaluating the response to any type of antihypertensive treatment and may improve adherence; (7) The target HBPM goal for treatment is <135/85 mm Hg or <130/80 mm Hg in high-risk patients; (8) HBPM is useful in the elderly, in whom both BP variability and the white-coat effect are increased; (9) HBPM is of value in patients with diabetes, in whom tight BP control is of paramount importance; (10) Other populations in whom HBPM may be beneficial include pregnant women, children, and patients with kidney disease; and (11) HBPM has the potential to improve the quality of care while reducing costs and should be reimbursed.

Call to action on use and reimbursement for home blood pressure monitoring: a joint scientific statement from the American Heart Association, American Society Of Hypertension, and Preventive Cardiovascular Nurses Association

Home blood pressure monitoring (HBPM) overcomes many of the limitations of traditional office blood pressure (BP) measurement and is both cheaper and easier to perform than ambulatory BP monitoring. Monitors that use the oscillometric method are currently available that are accurate, reliable, easy to use, and relatively inexpensive. An increasing number of patients are using them regularly to check their BP at home, but although this has been endorsed by national and international guidelines, detailed recommendations for their use have been lacking. There is a rapidly growing literature showing that measurements taken by patients at home are often lower than readings taken in the office and closer to the average BP recorded by 24-hour ambulatory monitors, which is the BP that best predicts cardiovascular risk. Because of the larger numbers of readings that can be taken by HBPM than in the office and the elimination of the white-coat effect (the increase of BP during an office visit), home readings are more reproducible than office readings and show better correlations with measures of target organ damage. In addition, prospective studies that have used multiple home readings to express the true BP have found that home BP predicts risk better than office BP (Class IIa; Level of Evidence A). This call-to-action article makes the following recommendations: (1) It is recommended that HBPM should become a routine component of BP measurement in the majority of patients with known or suspected hypertension; (2) Patients should be advised to purchase oscillometric monitors that measure BP on the upper arm with an appropriate cuff size and that have been shown to be accurate according to standard international protocols. They should be shown how to use them by their healthcare providers; (3) Two to 3 readings should be taken while the subject is resting in the seated position, both in the morning and at night, over a period of 1 week. A total of >or=12 readings are recommended for making clinical decisions; (4) HBPM is indicated in patients with newly diagnosed or suspected hypertension, in whom it may distinguish between white-coat and sustained hypertension. If the results are equivocal, ambulatory BP monitoring may help to establish the diagnosis; (5) In patients with prehypertension, HBPM may be useful for detecting masked hypertension; (6) HBPM is recommended for evaluating the response to any type of antihypertensive treatment and may improve adherence; (7) The target HBPM goal for treatment is <135/85 mm Hg or <130/80 mm Hg in high-risk patients; (8) HBPM is useful in the elderly, in whom both BP variability and the white-coat effect are increased; (9) HBPM is of value in patients with diabetes, in whom tight BP control is of paramount importance; (10) Other populations in whom HBPM may be beneficial include pregnant women, children, and patients with kidney disease; and (11) HBPM has the potential to improve the quality of care while reducing costs and should be reimbursed.

A hydrostatic pressure approach to cuffless blood pressure monitoring

This paper presents the underlying principle and accompanying initial validation results towards the development of an optically-based, cuffless blood pressure monitoring method. As opposed to traditional oscillometric techniques, the optical sensor is calibrated with a known patient-controlled hydrostatic perturbation. In particular, the hydrostatic pressure challenge is utilized to parameterize the characteristic sigmoidal vascular compliance curve that links transmural pressure to the measured PPG output. Formulation of the compliance model will be accompanied by experimental results demonstrating the utility of the method.