Wearable Blood Pressure Monitoring Research Articles

Transforming blood pressure control in primary care through a novel remote decision support strategy based on wearable blood pressure monitoring: The NEXTGEN-BP randomized trial protocol

Despite high blood pressure being the leading preventable risk factor for death, only 1 in 3 patients achieve target blood pressure control. Key contributors to this problem are clinical inertia and uncertainties in relying on clinic blood pressure measurements to make treatment decisions. The NEXTGEN-BP open-label, multicenter, randomized controlled trial will investigate the efficacy, safety, acceptability and cost-effectiveness of a wearable blood pressure monitor-based care strategy for the treatment of hypertension, compared to usual care, in lowering clinic blood pressure over 12 months. NEXTGEN-BP will enroll 600 adults with high blood pressure, treated with 0 to 2 antihypertensive medications. Participants attending primary care practices in Australia will be randomized 1:1 to the intervention of a wearable-based remote care strategy or to usual care. Participants in the intervention arm will undergo continuous blood pressure monitoring using a wrist-wearable cuffless device (Aktiia, Switzerland) and participate in 2 telehealth consultations with their primary care practitioner (general practitioner [GP]) at months 1 and 2. Antihypertensive medication will be up-titrated by the primary care practitioner at the time of telehealth consults should the percentage of daytime blood pressure at target over the past week be <90%, if clinically tolerated. Participants in the usual care arm will have primary care consultations according to usual practice. The primary outcome is the difference between intervention and control in change in clinic systolic blood pressure from baseline to 12 months. Secondary outcomes will be assessed at month 3 and month 12, and include acceptability to patients and practitioners, cost-effectiveness, safety, medication adherence and patient engagement. NEXTGEN-BP will provide evidence for the effectiveness and safety of a new paradigm of wearable cuffless monitoring in the management of high blood pressure in primary care. ACTRN12622001583730.

Wearable Continuous Blood Pressure Monitoring Devices Based on Pulse Wave Transit Time and Pulse Arrival Time: A Review.

Continuous blood pressure (BP) monitoring is of great significance for the real-time monitoring and early prevention of cardiovascular diseases. Recently, wearable BP monitoring devices have made great progress in the development of daily BP monitoring because they adapt to long-term and high-comfort wear requirements. However, the research and development of wearable continuous BP monitoring devices still face great challenges such as obvious motion noise and slow dynamic response speeds. The pulse wave transit time method which is combined with photoplethysmography (PPG) waves and electrocardiogram (ECG) waves for continuous BP monitoring has received wide attention due to its advantages in terms of excellent dynamic response characteristics and high accuracy. Here, we review the recent state-of-art wearable continuous BP monitoring devices and related technology based on the pulse wave transit time; their measuring principles, design methods, preparation processes, and properties are analyzed in detail. In addition, the potential development directions and challenges of wearable continuous BP monitoring devices based on the pulse wave transit time method are discussed.

Tests for the identification of reflex syncope mechanism

ABSTRACT Introduction Treatment efficacy of reflex syncope is mainly related to the mechanism underlying syncope rather than its etiology or clinical presentation. The predominant mechanism underlying reflex syncope can be assigned to hypotensive or to bradycardic phenotypes. Areas covered Methodology and diagnostic criteria of the most useful tests for the identification of hypotensive and bradycardic phenotypes are discussed. Diagnostic tests for the hypotensive phenotype include office blood pressure measurement with active standing test, home, and wearable blood pressure monitoring, 24-h ambulatory blood pressure monitoring and tilt table test. Diagnostic tests for the bradycardic phenotype include carotid sinus massage, tilt table test and prolonged ECG monitoring. Expert opinion In reflex syncope, the documentation of bradycardia/asystole during a syncopal episode does not rule out the possibility that a preceding or parallel hypotensive reflex plays an important role. Similarly, even when a hypotensive mechanism is established, the possibility of an associated cardioinhibitory reflex should be investigated. Investigating the mechanism of reflex syncope is mandatory in patients with severe recurrent episodes, with the final aim to develop a personalized treatment strategy. Recent trials have demonstrated the benefits of personalized mechanism-based therapy, thus highlighting the importance of a comprehensive assessment of the mechanisms underlying syncope.

PS-C07-7: EFFECTS OF PSYCHOLOGICAL STRESS AND PHYSICAL ACTIVITY ON AMBULATORY BLOOD PRESSURE AND PULSE RATE VARIABILITY

Objectives: Physical activity and psychological stress during daily life contribute to ambulatory blood pressure (BP) variability. This study aims to investigate the effects of physical activity and psychological stress on daytime BPs measured by ABPM. Methods: This study is a post-hoc analysis using ABPM data from a comparison study of ambulatory BP measured by a wrist watch-type wearable BP monitoring device and an ABPM device. ABPM was performed at 30-min intervals for 24 h using a TM-2441 device (A&amp;D Co., Tokyo), an oscillometric device with an upper-arm BP-cuff. This device is also equipped with a high-sensitivity actigraph that can detect fine-scale physical movements of the wearer in three directions. Physical activity was calculated as the sum of the actigraphically measured physical activity over the 5 min before each ABPM measurement. Study participants were asked to write a self-report diary of their general situation (i.e., location, emotion, and body position) corresponding to each BP measurement at least 10 times while awake. Results: From 50 outpatients (mean age 66.1 ± 10.8 years, 60.0% male, 98.0% hypertensive patients), 1580 daytime BP readings were taken by ABPM. Of these, 642 BP readings had corresponding diary information. In the mixed effect model analysis including physical activity, significant systolic BP (SBP) elevation associated with physical activity was observed in both a dataset of 1580 BP readings (2.9 ± 0.9 mmHg, P = 0.001 for light physical activity; and 2.9 ± 1.4 mmHg, P = 0.045 for moderate physical activity) and a dataset of 642 BP readings (2.5 ± 1.2 mmHg, P = 0.043 for light physical activity; and 4.2 ± 2.0 mmHg, P = 0.036 for moderate physical activity). In the analysis of 642 BP readings using the model including physical activity and situational factors from diary information, SBP was significantly higher during negative emotions than during positive emotions (7.4 ± 2.5 mmHg, p = 0.003), while the SBP change to physical activity decreased and was not statistically significant. On the other hand, pulse rate was unchanged by negative emotions, but was increased for physical activity. Conclusions: Daytime BP measured by ABPM was elevated to a greater extent by psychological stress than by physical activity. BP elevation without corresponding pulse rate increase might be influenced by psychological stress. Simultaneous monitoring of BP and physical activity might detect BP elevation caused by psychological stress.

S-58-2: CUFFLESS WEARABLE 24-HOUR BLOOD PRESSURE MONIT ORING VERSUS STANDARD AMBULATORY MONITORING

Objective: Cuffless wearable blood pressure (BP) monitors have great potential in assessing 24-hour BP without user disturbance for weeks and months. However, it is uncertain whether these devices can accurately track BP changes during usual daily activities and sleep as with standard 24-hour ambulatory BP monitoring (ABPM). We assessed daytime and nighttime BP using a commercially available cuffless wearable BP device versus classic ABPM. Design and method: We included 45 individuals (age 58 ± 14 years [mean ± SD], 33% female, 80% hypertensive) in two centres (Perth, Australia; Athens, Greece). Participants used a cuffless wearable BP monitor (Aktiia, Switzerland) continuously for 7–10 days and 24-hour ABPM (MicroLife WatchBP O3, Switzerland) on the first and the last day of cuffless BP monitoring. Daily 24-hour, daytime, and nighttime BP values were averaged across the total study days for the cuffless device and across the two ABPM days. Results: The cuffless device reported higher systolic BP for 24-hours by 6.8 mmHg, 95%CI [3.7, 9.7], daytime by 3.8 mmHg [1.0, 6.7], and nighttime by 17.5 mmHg [13.6, 21.4] (all p &lt; 0.01). Cuffless 24-hour diastolic BP was comparable with ABPM (difference 1.2 mmHg, 95%CI [-1.0, 3.5]), as was daytime diastolic BP (-0.8 mmHg [-3.0, 1.3]) (both p. &lt; 27). However, the cuffless device reported higher nighttime diastolic BP by 9.2 mmHg, 95%CI [6.3, 12.2] (p &lt; 0.001). Nighttime dip as measured by the cuffless device, namely systolic BP (-5.1 mmHg, 95%CI [-13.7, 3.6]) and diastolic BP (-3.8 mmHg [-11.6, 4.2]) were substantially less than ABPM (systolic BP dip: -18.0 mmHg [-35.5, -1.2]; diastolic BP dip: -13.8 mmHg [-27.2, -0.8]). The cuffless device identified 44 nighttime non-dippers (defined as a relative dip &lt; 10%) for systolic BP and 42 non-dippers for diastolic BP, compared to 10 non-dippers for both systolic and diastolic BP as identified by ABPM (both comparisons p &lt; 0.001). Conclusions: The Aktiia cuffless wearable BP device considerably overestimated average systolic BP compared to classic ABPM and was unable to adequately track diurnal BP variation.

Abstract 10186: Accuracy Study of Wearable Devices for Monitoring Blood Pressure in Acute Stroke Patients

Objective: The fluctuations of blood pressure in the acute stage of stroke are associated with neurological deterioration and poor prognosis. Although continuous monitoring of blood pressure changes becomes possible with the emergence of wearable blood pressure monitoring equipment, the accuracy of the equipment is still in doubt. Here, the accuracy of the optoelectronic-based wearable device for blood pressure monitoring in hospitalized patients with acute stroke were investigated and verified. Methods: Thirty-five acute stroke patients in the Department of Neurology of a teaching hospital were recruited. With the blood pressure values measured by bedside ECG monitor as the gold standard, wearables devices (wearable wrist watch) and bedside ECG monitors were monitored sequentially the same upper limb at the same time and recorded every 2 hours during the first 24 hours of admission. Receiver operating characteristic (ROC) curves were employed to determine the optimal cut off points and tests of sensitivity, specificity, kappa coefficients were conducted. Results: The average age of participants (male 17, female 18) was 61.91 ±8.72 years. 414 groups of blood pressure values were measured and ranged from 74/41 to 221/124 mmHg. The kappa value of systolic blood pressure (SBP) measured by wearable wrist watch and bedside ECG monitor was 0.768, with 89.1% sensitivity and 87.7% specificity (Table 1-A). And the kappa value of diastolic blood pressure (DBP) was 0.648, with 94.6% sensitivity and 67.9% specificity (Table 1-B). The area under ROC curve for SBP diagnosis and DBP diagnosis of wearable wrist watches were 0.941 ( p &lt; 0.001, Figure 1-A) and 0.939 ( p &lt; 0.001, Figure 1-B) respectively. There was no significant difference in SBP and DBP between these two methods ( p &gt;0.05, Table 3). Conclusions: The accuracy of wearable wrist watch for measuring patient blood pressure with acute stroke is good enough for ambulatory blood pressure monitoring of acute stroke patients.

VALIDATION OF THE OPTICAL AKTIIA BRACELET IN DIFFERENT BODY POSITIONS FOR THE PERSISTENT MONITORING OF BLOOD PRESSURE

Objective: The diagnosis of hypertension and the adjustment of antihypertensive drugs are evolving from repeated isolated measurements performed at the physician offices to the full phenotyping of patients in real-life conditions. Indeed, epidemiologic data show that prediction of risk is largely improved when blood pressure (BP) is measured out of the doctor’s office. Today, out-of-office measurements of BP are mostly performed by a series of self-measurements done at home over several days (HBPM monitoring), or automatically for 24 hours (ABPM monitoring). None of these approaches allow assessing and tracking the 24 hour hypertensive phenotype of patients in the long term. The aim of this study was to demonstrate that a wearable BP monitor (the CE-marked Aktiia Bracelet) can accurately estimate BP in the most common body positions of daily life and thus become a candidate solution for the long-term BP phenotyping of patients. Design and method: We recruited 91 patients with BP ranging from low to hypertensive levels and compared BP values from the Aktiia Bracelet against auscultatory reference values for four weeks at different body positions according to an extended and adapted ISO 81060-2 protocol. Results: The observed means and standard deviations of differences for systolic BP were of 0.46 ± 7.75 mmHg in the sitting position, -2.44 ± 10.15 mmHg in the lying, -3.02 ± 6.10 mmHg in the sitting with the device on the lap, and -0.62 ± 12.51 mmHg in the standing position. Differences for diastolic BP readings were respectively of 0.39 ± 6.86 mmHg, -1.93 ± 7.65 mmHg, 4.22 ± 6.56 mmHg and -4.85 ± 9.11 mmHg. For the sitting and relax position (for which the ISO 81060–2 performance criteria are applicable) the Aktiia Bracelet met criterion 1 and criterion 2. Conclusions: This study demonstrates that the optical Aktiia Bracelet can accurately estimate BP in the most common body positions compared to auscultation, although precision varies across positions. These findings pave the way to the use of this wearable device for the persistent monitoring of BP, and the further identification of individual BP phenotypes at scale.

A SMART SENSING MODULE AIMS AT REDUCTION OF MOTION ARTIFACT FOR WEARABLE TONOMETRY BLOOD PRESSURE DEVICE

Objective: This work focuses on development a unique mini sensing module to alleviate muscle action induced rtefacts and in the meanwhile to enable the alignment free capability for radial BP measurement. Design and method: The coupling variations from motion rtefacts tremendously distorts the sensing signal thus leads the measuring results unreliable and limits the applications of wearable blood pressure monitoring in daily life. It is key to have capability of sensing and recognizing the muscle action induced stress at the measuring site and then have the opportunity to eliminate misleading coupling variation. The mini sensing module consists of two independent sensing channels, which are neighboring distributed in parallel (Fig. 1). The channels are arranged enough close with the spacing only 2 mm in order to guarantee them sensing the same induced stress. The two channels have identical dimension feature with10 mm length and 3 mm width. And a 3 mm × 3 mm hard block is integrated into the middle segment of one channel. The channels are filled with degassed silicon oil and a silicon die is embedded and serves as pressure sensor unit. TPU flexible film is used to seal the channels, which serves also as the mechanical stimulation interface. The smart module is fixed to wrist with channel direction transversal to the arterial path during radial BP measuring. The blocked channel isolates completely (partly at least) stimulating from the vascular and serves as skin stress sensing reference, and the other sensing channel gets combination of the skin stress together with fully stimulating of vascular BP. It is straightforward that the difference two signal can partly at least eliminate the stress induced error, which also is presented in Fig.2. Further rtefacts reduction can be achieved by exploiting specific adaptive filtering algorithm with the blocked signal as disturbance input and the other as source. Results: Experiments have proved the effectiveness of the scheme. Conclusions: By comparison with the BP signal under optimal condition, the sensing module can provide with accurate BP pulse waves in the presence of motion interference.

Wearable blood pressure measurement devices and new approaches in hypertension management: the digital era.

Out-of-office blood pressure (BP) measurement is considered an integral component of the diagnostic algorithm and management of hypertension. In the era of digitalization, a great deal of wearable BP measuring devices has been developed. These digital blood pressure monitors allow frequent BP measurements with minimal annoyance to the patient while they do promise radical changes regarding the diagnostic accuracy, as the importance of making an accurate diagnosis of hypertension has become evident. By increasing the number of BP measurements in different conditions, these monitors allow accurate identification of different clinical phenotypes, such as masked hypertension and pathological BP variability, that seem to have a negative impact on cardiovascular prognosis. Frequent measurements of BP and the incorporation of new features in BP variability, both enable well-rounded interpretation of BP data in the context of real-life settings. This article is a review of all different technologies and wearable BP monitoring devices.

Development of Continuous Blood Pressure Measurement System Using Photoplethysmograph and Pulse Transit Time

It is not only a problem for old age anyone. So, blood pressure is the one provides importance information with vital signs about cardiovascular health using oscillometric method. Unfortunately, this method required inflation and following deflation of the cuff. This method only gives instantaneous blood pressure and continuous measurement is not available. It is not available to the patients that required long term monitoring. To overcome this problem, the development of Continuous Non-Invasive Blood Pressure (NIBP) algorithm based on Pulse Transit Time (PTT) using two channel Photoplethysmograph (PPG) is proposed in this study. PPG is a non-invasive device for detecting blood volume changes can be affected by various physiological factors, analysis of the PPG signal can provide sufficient information on the human health condition; more specifically their cardio-vascular related performance. Literatures show that the PTT has linear relationship with blood pressure. Nevertheless, the determination of the model structure, order and real-time implementation to offer a continuous measurement of the PTT still remains challenging tasks in this area. PTT can be as index to monitor cardiovascular disease. In this project, dynamic model based on pulse transit time will be proposed to continuously monitor blood pressure by using PPG signals. Different kind of resolutions in microcontroller combined with PPG sensor will be used as well. MATLAB software is also been applied for PTT calculation based on two PPG sensors. PPG is method for detect blood volume changes with optical source transmitter send from one end and received the signal from another by receiver through body tissue as medium. MATLAB functions as Digital Signal Processing (DSP) for signals received in computer. Linear Regression technique and Fung's algorithm are applied to obtain the best fit line for all the points in order to systolic and diastolic blood pressure measurement. The results showed that the algorithm based on pulse transit time has been developed for the assessment of blood pressure and justify patient’ condition with 86.34% and 88.20% accuracy. Finally, this technique is a simple, user friendly and operator independent PPG system suitable for long term and wearable blood pressure monitor.

Relationship between blood pressure repeatedly measured by a wrist-cuff oscillometric wearable blood pressure monitoring device and left ventricular mass index in working hypertensive patients.

This study sought to evaluate the relationship between blood pressure (BP) taken by a new wrist-cuff oscillometric wearable BP monitoring device and left ventricular mass index measured by cardiac magnetic resonance imaging (cMRI-LVMI) in 50 hypertensive patients (mean age 60.5 ± 8.9 years, 92.0% men, 96% treated for hypertension) with regular employment. Participants were asked to self-measure their wearable BPs twice in the morning and evening under a guideline-recommended standardized home BP measurement, and once each at five predetermined times and any additional time points under an ambulatory condition for a maximum of 7 days. In total, 2105 wearable BP measurements (home BP: 747 [morning: 409, evening: 338], ambulatory condition: 1358 [worksite: 942]) were collected over 5.5 ± 1.2 days. The average of all wearable systolic BP (SBP) readings (129.8 ± 11.0 mmHg) was weakly correlated with cMRI-LVMI (r = 0.265, p = 0.063). Morning home wearable SBP average (128.5 ± 13.8 mmHg) was significantly correlated with cMRI-LVMI (r = 0.378, p = 0.013), but ambulatory wearable SBP average (132.5 ± 12.7 mmHg) was not (r = 0.215, p = 0.135). The averages of the highest three values of all wearable SBPs (153.3 ± 13.9 mmHg) and ambulatory wearable SBPs (152.9 ± 13.9 mmHg) were 16 mmHg higher than that of the morning home wearable SBPs (137.0 ± 15.9 mmHg). Those peak values were significantly correlated with cMRI-LVMI (r = 0.320, p = 0.023; r = 0.310, p = 0.029; r = 0.451, p = 0.002, respectively). In conclusion, an increased number of wearable BP measurements, which could detect individual peak BP, might add to the clinical value of these measurements as a complement to the guideline-recommended home BP measurements, but further studies are needed to confirm these findings.

Ambulatory Blood Pressure Monitoring to Diagnose and Manage Hypertension.

This review portrays how ambulatory blood pressure (BP) monitoring was established and recommended as the method of choice for the assessment of BP and for the rational use of antihypertensive drugs. To establish much-needed diagnostic ambulatory BP thresholds, initial statistical approaches evolved into longitudinal studies of patients and populations, which demonstrated that cardiovascular complications are more closely associated with 24-hour and nighttime BP than with office BP. Studies cross-classifying individuals based on ambulatory and office BP thresholds identified white-coat hypertension, an elevated office BP in the presence of ambulatory normotension as a low-risk condition, whereas its counterpart, masked hypertension, carries a hazard almost as high as ambulatory combined with office hypertension. What clinically matters most is the level of the 24-hour and the nighttime BP, while other BP indexes derived from 24-hour ambulatory BP recordings, on top of the 24-hour and nighttime BP level, add little to risk stratification or hypertension management. Ambulatory BP monitoring is cost-effective. Ambulatory and home BP monitoring are complimentary approaches. Their interchangeability provides great versatility in the clinical implementation of out-of-office BP measurement. We are still waiting for evidence from randomized clinical trials to prove that out-of-office BP monitoring is superior to office BP in adjusting antihypertensive drug treatment and in the prevention of cardiovascular complications. A starting research line, the development of a standardized validation protocol for wearable BP monitoring devices, might facilitate the clinical applicability of ambulatory BP monitoring.

Management of Hypertension in the Digital Era: Small Wearable Monitoring Devices for Remote Blood Pressure Monitoring.

Out-of-office blood pressure measurement is an essential part of diagnosing and managing hypertension. In the era of advanced digital health information technology, the approach to achieving this is shifting from traditional methods (ambulatory and home blood pressure monitoring) to wearable devices and technology. Wearable blood pressure monitors allow frequent blood pressure measurements (ideally continuous beat-by-beat monitoring of blood pressure) with minimal stress on the patient. It is expected that wearable devices will dramatically change the quality of detection and management of hypertension by increasing the number of measurements in different situations, allowing accurate detection of phenotypes that have a negative impact on cardiovascular prognosis, such as masked hypertension and abnormal blood pressure variability. Frequent blood pressure measurements and the addition of new features such as monitoring of environmental conditions allows interpretation of blood pressure data in the context of daily stressors and different situations. This new digital approach to hypertension contributes to anticipation medicine, which refers to strategies designed to identify increasing risk and predict the onset of cardiovascular events based on a series of data collected over time, allowing proactive interventions to reduce risk. To achieve this, further research and validation is required to develop wearable blood pressure monitoring devices that provide the same accuracy as current approaches and can effectively contribute to personalized medicine.

Achieving Optimal Gestational Weight Gain, Birth Weight, and Perinatal Outcomes Among Pregnant Women at Risk of Hypertension: Protocol for a Pilot Randomized Controlled Trial.

BackgroundHypertensive disorders, including preeclampsia, complicate 10% of all pregnancies, causing maternal and fetal morbidity and mortality. In Bangladesh, 24% of all maternal deaths are directly attributed to hypertensive disorders. Conventional antenatal care practices often delay or miss detecting hypertensive disorders in pregnancy, which may allow some women to become vulnerable to the adverse consequences of the hypertensive disorders. Regular self-monitoring of blood pressure and weight gain may improve maternal and fetal outcomes among pregnant women at risk of developing hypertensive disorders during pregnancy through early diagnosis, prompt referral, and timely clinical management; however, to undertake a randomized controlled trial of an intervention to reduce adverse consequences of hypertensive disorders in pregnancy, its feasibility must first be determined.ObjectiveThe objectives of this study are to evaluate the accuracy of a wearable blood pressure monitoring device (Health Gauge) in order to test the design and methods of a future definitive randomized controlled trial, and to examine the feasibility, acceptability, and fidelity of an intervention focusing on regular monitoring of weight gain and self-monitoring of blood pressure for pregnant women at risk of developing hypertensive disorders and their associated complications.MethodsThe study is located in Matlab, Bangladesh will be conducted in two phases. First, a wearable blood pressure device (Health Gauge) will be validated in accordance with the European Society of Hypertension International Protocol (revision 2010). Second, a prospective, two-arm, parallel, and nonblinded randomized controlled external pilot trial will be conducted. In the pilot trial, 70 eligible participants will be individually randomized to the intervention arm, in which pregnant women will self-monitor their blood pressure daily using a wearable device (Health Gauge) and be evaluated monthly by trained health workers for weight gain from 20 weeks of gestation until delivery, or the control arm, in which pregnant women will be assessed for weight gain every two months from 20 weeks of gestation until delivery (1:1 intervention to control allocation ratio using a permuted block randomization method with concealment). All women will receive standard antenatal care.ResultsA validation study of the wearable blood pressure device has successfully been conducted among the general adult population in Matlab, Bangladesh. As of September 2019, the pilot trial has completed enrollment of women who are pregnant (N=70; intervention: n=35; control: n=35) and follow-up of the participants is ongoing. Data analysis is expected to be completed by June 2020, and results are expected to be submitted for publication in August 2020.ConclusionsThe findings of this study will help us to design a comprehensive, full-scale randomized controlled trial to test the efficacy of regular self-monitoring of blood pressure and weight gain during pregnancy, a simple and inexpensive intervention to help to achieve optimal maternal and fetal outcomes in pregnant women at risk of developing hypertensive disorders and their associated complications during pregnancy.Trial RegistrationClinicalTrials.gov NCT03858595; https://clinicaltrials.gov/ct2/show/NCT03858595International Registered Report Identifier (IRRID)DERR1-10.2196/16676

Adherence with blood pressure monitoring wearable device among the elderly with hypertension: The case of rural China.

IntroductionWearable blood pressure (BP) monitor devices are increasingly adopted owing to the promotion of hypertension management program. However, little is known about the adherence and its associated factors in older adults (OAs) with hypertension.MethodsThe aim of this study was to determine factors associated with adherence to wearable BP monitor. In total, 212 OAs with hypertension in a remote rural area in China were asked to wear a BP monitor over 1‐month period. The following information on associated factors for adherence was collected, including demographic characteristics, cardiovascular health measurements, technology fluency, the Compliance of Hypertensive Patients' Scale, and the Health‐related Quality of Life Survey. As a result, the mean age of the 212 hypertension participants was 71.32 years (SD = 6.81).ResultsDuring the 30‐day survey, 50.94% of the participants with daily recoded BP wristband data were assigned as “BP device users.” The binary logistic regression model revealed that lower lifestyle compliance, lower medication compliance and higher total hypertension compliance were significant predictors for adherence. However, there were no differences concerning cardiovascular health factors, technology fluency, and health‐related quality of life between device users and nonusers.ConclusionIndividuals reporting a higher level of total compliance in hypertension management were more likely to wear a BP monitor device among OAs with hypertension. In addition, further research is needed to determine how wearable mHealth technology can be used to develop better hypertension self‐management education programs for this population.

Validation and Acceptability of a Cuffless Wrist-Worn Wearable Blood Pressure Monitoring Device Among Users and Health Care Professionals: Mixed Methods Study.

BackgroundBlood pressure (BP) is an important modifiable cardiovascular risk factor, yet its long-term monitoring remains problematic. Wearable cuffless devices enable the capture of multiple BP measures during everyday activities and could improve BP monitoring, but little is known about their validity or acceptability.ObjectiveThis study aimed to validate a wrist-worn cuffless wearable BP device (Model T2; TMART Technologies Limited) and assess its acceptability among users and health care professionals.MethodsA mixed methods study was conducted to examine the validity and comparability of a wearable cuffless BP device against ambulatory and home devices. BP was measured simultaneously over 24 hours using wearable and ambulatory devices and over 7 days using wearable and home devices. Pearson correlation coefficients compared the degree of association between the measures, and limits of agreement (LOA; Bland-Altman plots) were generated to assess measurement bias. Semistructured interviews were conducted with users and 10 health care professionals to assess acceptability, facilitators, and barriers to using the wearable device. Interviews were audio recorded, transcribed, and analyzed.ResultsA total of 9090 BP measurements were collected from 20 healthy volunteers (mean 20.3 years, SD 5.4; N=10 females). Mean (SD) systolic BP (SBP)/diastolic BP (DBP) measured using the ambulatory (24 hours), home (7 days), and wearable (7 days) devices were 126 (SD 10)/75 (SD 6) mm Hg, 112 (SD 10)/71 (SD 9) mm Hg and 125 (SD 4)/77 (SD 3) mm Hg, respectively. Mean (LOA) biases and precision between the wearable and ambulatory devices over 24 hours were 0.5 (−10.1 to 11.1) mm Hg for SBP and 2.24 (−17.6 to 13.1) mm Hg for DBP. The mean biases (LOA) and precision between the wearable and home device over 7 days were −12.7 (−28.7 to 3.4) mm Hg for SBP and −5.6 (−20.5 to 9.2) mm Hg for DBP. The wearable BP device was well accepted by participants who found the device easy to wear and use. Both participants and health care providers agreed that the wearable cuffless devices were easy to use and that they could be used to improve BP monitoring.ConclusionsWearable BP measures compared well against a gold-standard ambulatory device, indicating potential for this user-friendly method to augment BP management, particularly by enabling long-term monitoring that could improve treatment titration and increase understanding of users’ BP response during daily activity and stressors.

Cuff-less and Calibration-free Blood Pressure Estimation Using Convolutional Autoencoder with Unsupervised Feature Extraction.

Monitoring blood pressure (BP) in people's daily life in an unobtrusive way is of great significance to prevent cardiovascular disease and its complications. However, most of the current cuff-less BP estimation methods still suffer from two drawbacks including calibration and tedious feature selection. In this study, we first attempt to validate the feasibility of convolutional autoencoder (CAE) to estimate continuous BP without calibration and hand-crafted feature extraction. 62 subjects were recruited in this experiment. We first trained the CAE on all the data to extract the unsupervised features. Then, we trained a regressor to estimate BP values using the features learning from the CAE. 10-fold cross-validation tests were used to examine the performance of our models. Finally, it has been demonstrated that the accuracy of the predicted BP satisfied the Grade B standard of British Hypertension Society. Due to its calibration-free and unsupervised feature learning ability from the collected signal, the proposed method has high prospects for application in wearable BP monitoring device.

고혈압 고령자 대상 웨어러블 혈압계의 측정 타당성 및 의복기후의 영향

고혈압 고령자 대상 웨어러블 혈압계의 측정 타당성 및 의복기후의 영향

SeismoWatch: Wearable Cuffless Blood Pressure Monitoring Using Pulse Transit Time.

The current norm for measuring blood pressure (BP) at home is using an automated BP cuff based on oscillometry. Despite providing a viable and familiar method of tracking BP at home, oscillometric devices can be both cumbersome and inaccurate with the inconvenience of the hardware typically limiting measurements to once or twice per day. To address these limitations, a wrist-watch BP monitor was developed to measure BP through a simple maneuver: holding the watch against the sternum to detect micro-vibrations of the chest wall associated with the heartbeat. As a pulse wave propagates from the heart to the wrist, an accelerometer and optical sensor on the watch measure the travel time - pulse transit time (PTT) - to estimate BP. In this paper, we conducted a study to test the accuracy and repeatability of our device. After calibration, the diastolic pressure estimations reached a root-mean-square error of 2.9 mmHg. The watch-based system significantly outperformed (p<0.05) conventional pulse arrival time (PAT) based wearable blood pressure estimations - the most commonly used method for wearable BP sensing in the existing literature and commercial devices. Our device can be a convenient means for wearable BP monitoring outside of clinical settings in both health-conscious and hypertensive populations.1.

Novel blood pressure estimation method using single photoplethysmography feature.

Continuous blood pressure (BP) monitoring has a significant meaning to the prevention and early diagnosis of cardiovascular disease. However, existing continuous BP monitoring approaches, especially cuff-less BP monitoring approaches, are all contraptions which complex and huge computation required. For example, for the most sophisticated cuff-less BP monitoring method using pulse transit time (PTT), the simultaneous record of photoplethysmography (PPG) signal and electrocardiography (ECG) are required, and various measurement of characteristic points are needed. These issues hindered widely application of cuff less BP measurement in the wearable devices. In this study, a novel BP estimation method using single PPG signal feature was proposed and its performance in BP estimation was also tested. The results showed that the new approach proposed in this study has a mean error -0.91 ± 3.84 mmHg for SBP estimation and -0.36 ± 3.36 mmHg for DBP estimation respectively. This approach performed better than the traditional PTT based BP estimation, which mean error for SBP estimation was -0.31 ± 4.78 mmHg, and for DBP estimation was -0.18 ± 4.32 mmHg. Further investigation revealed that this new BP estimation approach only required measurement of one characteristic point, reducing much computation when implementing. These results demonstrated that this new approach might be more suitable implemented in the wearable BP monitoring devices.