A smartwatch sphygmomanometer-based model for predicting short-term new-onset hypertension in individuals with high-normal blood pressure: a cohort study.

OBJECTIVES: The objective was to utilize a smartwatch sphygmomanometer to predict new-onset hypertension within a short-term follow-up among individuals with high-normal blood pressure (HNBP). METHODS: This study consisted of 3180 participants in the training set and 1000 participants in the validation set. Participants underwent both ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM) using a smartwatch sphygmomanometer. Multivariable Cox regressions were used to analyze cumulative events. A nomogram was constructed to predict new-onset hypertension. Discrimination and calibration were assessed using the C-index and calibration curve, respectively. RESULTS: Among the 3180 individuals with HNBP in the training set, 693 (21.8%) developed new-onset hypertension within a 6-month period. The nomogram for predicting new-onset hypertension had a C-index of 0.854 (95% CI, 0.843-0.867). The calibration curve demonstrated good agreement between the nomogram's predicted probabilities and actual observations for short-term new-onset hypertension. In the validate dataset, during the 6-month follow-up, the nomogram had a good C-index of 0.917 (95% CI, 0.904-0.930) and a good calibration curve. As the score increased, the risk of new-onset hypertension significantly increased, with an HR of 8.415 (95% CI: 5.153-13.744, p = .000) for the middle-score vs. low-score groups and 86.824 (95% CI: 55.071-136.885, p = .000) for the high-score vs. low-score group. CONCLUSIONS: This study provides evidence for the use of smartwatch sphygmomanometer to monitor blood pressure in individuals at high risk of developing new-onset hypertension in the near future. TRIAL REGISTRATION: ChiCTR2200057354.

Ability of a 24-h ambulatory cuffless blood pressure monitoring device to track blood pressure changes in clinical practice.

OBJECTIVE: There is an increasing number of cuffless blood pressure (BP) measurement (BPM) devices. Despite promising results when comparing single measurements, the ability of these devices to track changes in BP levels over 24 h related to an initial calibration BP (CalibBP) is unknown. Our aim was to analyse this ability in a cuffless device using pulse transit time. METHODS: We prospectively enrolled 166 participants for simultaneously performed cuffless (Somnotouch-NIBP) and cuff-based (Spacelabs 90217A/IEM Mobil-O-graph) 24 h BPM. As CalibBP for the cuffless device, first cuff-based BP was used. As surrogate for changes in BP levels after the CalibBP, we used the difference between the CalibBP and mean 24 h, awake and asleep BP measured by the two devices. In addition, we analysed the relationship between the difference of the CalibBP and the cuff-based BPM versus the difference between the cuff-based and the cuffless BPM devices. RESULTS: Mean(SD) difference between the CalibBP and mean 24hBP by the cuff-based or cuffless BP device were 7.4 (13.2) versus 1.8 (8.3) mmHg for systolic ( P  < 0.0001) and 6.6 (6.8) versus 1.6 (5.8) mmHg for diastolic ( P  < 0.0001). A near linear relationship was seen among the difference between the CalibBP and the cuff-based BPM values and the difference between the cuff-based and cuffless BPM device. CONCLUSION: Our data indicate a lower ability of the cuffless BPM device to track changes of BP levels after CalibBP. In addition, cuffless device accuracy was associated with the changes in BP levels after the initial CalibBP - the larger the BP level change, the larger the difference between the devices. REGISTRATION: https://www.clinicaltrials.gov ; Unique identifier: NCT03054688; NCT03975582.

Validation of the ANDON KD-595 automated upper-arm blood pressure monitor according to the universal standard.

OBJECTIVE: To validate the ANDON KD-595 automated upper-arm blood pressure monitor for clinical use and self-measurement blood pressure measurement according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard. METHODS: Same left-arm blood pressure was sequentially measured in 90 qualified adult participants and compared with a standard mercury sphygmomanometer. A total of 270 comparison pairs were obtained and analyzed according to the universal standard. RESULTS: For the validation Criterion 1 of the universal standard, the mean ± SD of the differences between the test device and reference blood pressure readings was 0.96 ±â€…5.35 and 0.82 ±â€…5.08 mmHg for SBP and DBP, respectively. For Criterion 2, the SDs of the averaged blood pressure differences between the test device and reference blood pressure per subject were 4.84 and 4.64 mmHg (with maximum allowed SDs of 6.87 and 6.89 mmHg) for SBP and DBP, respectively. CONCLUSION: The ANDON KD-595 automated upper-arm blood pressure monitor passed all the validation requirements according to the AAMI/ESH/ISO Universal Standard and can be recommended for clinical use and self-measurement blood pressure measurement in the general population.

Validation of the DBP-1333b upper-arm blood pressure monitor according to the AAMI/ESH/ISO universal standard (ISO 81060-2:2018+Amd.1:2020).

To evaluate the accuracy of the DBP-1333b upper-arm blood pressure (BP) measuring device in the adult population according to the AAMI/ESH/ISO universal standard (ISO 81060-2:2018+Amd.1:2020). Subjects were recruited in the adult population. The test device was an arm-type electronic sphygmomanometer (DBP-1333b) and the reference device was a desktop sphygmomanometer (XJ11D). Using the BP data measured by the desktop sphygmomanometer as reference BP, the accuracy of the non-invasive BP module of the test device was evaluated to determine whether it met the requirements. Data from 90 individuals were analysed. According to Criterion 1, the mean difference of SBP between the test and reference device was 0.19 mmHg and the SD was 7.45 mmHg. The mean difference of DBP was -0.59 mmHg and the SD was 6.47 mmHg. The mean difference of both SBP and DBP was less than 5 mmHg, and the SD was less than 8 mmHg, which met the requirements. According to Criterion 2, SD of SBP was 5.79 mmHg, which was less than 6.95 mmHg and met the requirements. The SD of DBP was 5.58 mmHg, which was less than 6.93 mmHg and met the requirements. It was concluded that the DBP-1333b complies with the AAMI/ESH/ISO universal standard (ISO 81060-2:2018+Amd.1:2020) and can be recommended for use by the adults.

Comparison of cuff inflation and cuff deflation brachial sphygmomanometry with intra-arterial blood pressure as reference.

Conventional sphygmomanometry with cuff deflation is used to calibrate all noninvasive BP (NIBP) instruments and the International Standard makes no mention of calibrating methods specifically for NIBP instruments, which estimate systolic and diastolic pressure during cuff inflation rather than cuff deflation. There is however increasing interest in inflation-based NIBP (iNIBP) instruments on the basis of shorter measurement time, reduction in maximal inflation pressure and improvement in patient comfort and outcomes. However, we have previously demonstrated that SBP estimates based on the occurrence of the first K1 Korotkoff sounds during cuff deflation can underestimate intra-arterial SBP (IA-SBP) by an average of 14 ±â€Š10 mmHg. In this study, we compare the dynamics of intra-arterial blood pressure (IABP) measurements with sequential measurement of Korotkoff sounds during both cuff inflation and cuff deflation in the same individual. In 40 individuals aged 64.1 ±â€Š9.6 years (range 36-86 years), the overall dynamic responses below the cuff were similar, but the underestimation error was significantly larger during inflation than deflation, increasing from 14 ±â€Š10 to 19 ±â€Š12 mmHg ( P  < 0.0001). No statistical models were found which could compensate for this error as were found for cuff deflation. The statistically significant BP differences between inflation and deflation protocols reported in this study suggest different behaviour of the arterial and venous vasculature between arterial opening and closing which warrant further investigation, particularly for iNIBP devices reporting estimates during cuff inflation. In addition, measuring Korotkoff sounds during cuff inflation represents significant technical difficulties because of increasing pump motor noise.

Development of a prediction equation to estimate lower-limb arterial occlusion pressure with a thigh sphygmomanometer.

INTRODUCTION: Previous investigators have developed prediction equations to estimate arterial occlusion pressure (AOP) for blood flow restriction (BFR) exercise. Most equations have not been validated and are designed for use with expensive cuff systems. Thus, their implementation is limited for practitioners. PURPOSE: To develop and validate an equation to predict AOP in the lower limbs when applying an 18 cm wide thigh sphygmomanometer (SPHYG18cm). METHODS: Healthy adults (n = 143) underwent measures of thigh circumference (TC), skinfold thickness (ST), and estimated muscle cross-sectional area (CSA) along with brachial and femoral systolic (SBP) and diastolic (DBP) blood pressure. Lower-limb AOP was assessed in a seated position at the posterior tibial artery (Doppler ultrasound) using a SPHYG18cm. Hierarchical linear regression models were used to determine predictors of AOP. The best set of predictors was used to construct a prediction equation to estimate AOP. Performance of the equation was evaluated and internally validated using bootstrap resampling. RESULTS: Models containing measures of either TC or thigh composition (ST and CSA) paired with brachial blood pressures explained the most variability in AOP (54%) with brachial SBP accounting for majority of explained variability. A prediction equation including TC, brachial SBP, and age showed good predictability (R2 = 0.54, RMSE = 7.18 mmHg) and excellent calibration. Mean difference between observed and predicted values was 0.0 mmHg and 95% Limits of Agreement were ± 18.35 mmHg. Internal validation revealed small differences between apparent and optimism adjusted performance measures, suggesting good generalizability. CONCLUSION: This prediction equation for use with a SPHYG18cm provided a valid way to estimate lower-limb AOP without expensive equipment.

Comparison of the Omron HeartGuide to the Welch Allyn ProBP 3400 blood pressure monitor.

Hypertension affects approximately 100 million U.S. adults and is the leading single contributing risk factor to all-cause mortality. Accurate blood pressure (BP) measurement is essential in the treatment of BP, and a number of devices exist for monitoring. Recently, a new watch-type design was released, the Omron HeartGuide (BP8000), with claims to provide clinically accurate BP measurement while also tracking activity and sleep similar to smart watches. The aim of this research was done in two studies: (1) evaluation of the HeartGuide device for measurement of resting BP and heart rate (HR); and (2) assessment of the HeartGuide for BP, HR, step-counting and sleep monitoring during activities of daily living. Study 1 compared the Omron HeartGuide to the previously validated Welch Allyn ProBP 3400 following a modified version of the Universal Standard for validation of BP measuring devices set by the AAMI/ESH/ISO. While resting HR measured by the HeartGuide was similar to Welch Allyn measures, both systolic and diastolic BP were significantly lower ( P ≤0.001), with differences of 10.4 (11.1) and 3.2 (10.0) mmHg, respectively. Study 2 compared HeartGuide measures to Welch Allyn measures for BP, HR, steps and sleep during various body positions (supine, seated, standing), physiological stressors (cold pressor test, lower body submersion, exercise), and free-living. The HeartGuide significantly underestimated BP though provided accurate HR during most conditions. It also significantly underestimated steps, but reported sleep measures similar to those subjectively reported. Based on the significant differences between the HeartGuide and Welch Allyn, our data indicate the HeartGuide is not a suitable replacement for existing BP monitors.

Reliability of systolic blood pressure measured by parents in young children at home using a hand held doppler device and aneroid sphygmomanometer.

OBJECTIVE: We report data regarding systolic BP monitoring in children aged <5 years performed over a 2-week period by parents at home using a hand-held doppler device and aneroid sphygmomanometer for SBP measurements (HDBPM). Our objectives were to compare health professional measured office systolic BP by doppler device (Office-SBP Doppler ) with parent measured home systolic BP using the same doppler device (Home-SBP Doppler ). We also report data evaluating reliability and optimal number of days of measurement required. DESIGN AND METHODS: We taught parents to measure systolic BP and assessed their technique using a hand-held doppler device and aneroid sphygmomanometer. We requested parents to perform three consecutive BP measurements twice daily (ideally morning and evening around similar times) when the child was awake, settled and cooperative. RESULTS: Over a 3-year period, data from 48 of 62 children who underwent HDBPM measurements were evaluated with median (IQR) age of 1.9 (0.9, 3.6) years, 27 (56%) boys and 14 (29%) on antihypertensive medication. Office-SBP Doppler was 2.9 ±â€Š8.9 mmHg [95% confidence interval (CI), -14.4 to 20.4, P  = 0.026] higher than Home-SBP Doppler . Mean Home-SBP Doppler between Week-1 and Week-2 monitoring was similar -0.45 ±â€Š3.5 mmHg (95% CI, -7.35 to 6.45, P  = 0.41). Morning HDBPM measurements were lower than evening with a mean difference of -2.77 ±â€Š3.92 mmHg, P  < 0.001). Over Week-1, mean Home-SBP Doppler was closer to mean Office-SBP Doppler with increasing cumulative days of monitoring and with smaller standard deviations suggesting that readings become more reliable from day 4 onwards. CONCLUSIONS: HDBPM is a reliable method for measuring systolic BP in young children with BP levels measured by parents comparable to those performed by health professional in clinic. HDBPM technique described here and performed by parents over a 7-day period with a minimum of 4-days, offers a reliable and reproducible technique to measure blood pressure at home.

Validation of the Wellvii VitalDetect blood pressure monitor in general population according to the International Standardization Organization 81060-2:2018.

OBJECTIVE: To evaluate the accuracy of the Wellvii VitalDetect automated oscillometric finger blood pressure monitor (single cuff size) for self/home blood pressure measurement according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2:2018). METHODS: According to the universal standard, a total of 92 participants were recruited and finally blood pressure of 85 eligible participants was sequentially measured and compared with a standard mercury sphygmomanometer. RESULTS: A total of 255 comparison pairs were obtained and analyzed based on the universal standard. For the validation criterion 1 of the ISO 81060-2:2018 universal standard, the mean ± SD of the differences between the test device and reference blood pressure readings was 1.66 ±â€…7.67 and 1.04 ±â€…6.45 mmHg for systolic and diastolic blood pressure, respectively. For criterion 2, the SD of the averaged blood pressure differences between the test device and reference blood pressure per subject was ± 6.49 mmHg (pass ≤ 6.73 mmHg) and ± 5.67 mmHg (pass ≤ 6.86 mmHg) for systolic and diastolic blood pressure, respectively. CONCLUSION: The Wellvii VitalDetect automated finger blood pressure monitor passed all the requirements for validation by the ISO 81060-2:2018 universal standard and can be recommended for self/home blood pressure measurement in general population.

Improving the accuracy of blood pressure measuring devices in Australia: a modelled return on investment study.

The VALID BP project was initiated to increase the availability of validated blood pressure measuring devices (BPMDs). The goal is to eliminate non validated BPMDs and minimise over- and underdiagnosis of hypertension caused by inaccurate readings. This study was undertaken to assess the potential return on investment in the VALID BP project. The Framework to Assess the Impact of Translational Health Research was applied to the VALID BP project. This paper focuses on the implementation of the cost benefit analysis aspect of this framework to monetise past research investment and model future research costs, implementation costs, and benefits. Analysis was based on reasoned assumptions about potential impacts from availability and use of validated BPMDs (assuming an end goal of 100% validated BPMDs available in Australia by 2028) and improved skills leading to more accurate BP measurement. After 5 years, with 20% attribution of benefits, there is a potential $1.14-$1.30 return for every dollar spent if the proportion of validated BPMDs and staff trained in proper BP measurement technique increased from 20% to 60%. After eight years (2020-2028) and assuming universal validation and training coverage, the returns would be between $2.70 and $3.20 per dollar spent (not including cost of side effects of unnecessary medication or downstream patient impacts from unmanaged hypertension). This modelled economic analysis indicates there will be positive downstream economic benefits if the availability of validated BPMDs is increased. The findings support ongoing efforts toward a universal regulatory framework for BPMDs and can be considered within more detailed future economic analyses.

Comparison of Home and Office Blood Pressure Devices in the Clinical Setting.

BACKGROUND: Self-measured blood pressure (SMBP) monitoring is increasingly used for remote hypertension management, but the real-world performance of home blood pressure (BP) devices is unknown. We examined BP measurements from patients' home devices using the American Medical Association's (AMA) SMBP Device Accuracy Test tool. METHODS: Patients at a single internal medicine clinic underwent up to five seated, same-arm BP readings using a home device and an automated BP device (Omron HEM-907XL). Following the AMA's three-step protocol, we used the patient's home device for the first, second, and fourth measurements and the office device for the third and fifth (if needed) measurements. Device agreement failure was defined as an absolute difference in systolic BP >10 mm Hg between the home and office devices in either of two confirmatory steps. Performance was examined by brand (Omron vs. non-Omron). Moreover, we examined patient factors associated with agreement failure via logistic regression models adjusted for demographic characteristics. RESULTS: We evaluated 152 patients (mean age 60 ±â€…15 years, 58% women, 31% Black) seen between October 2020 and November 2021. Device agreement failure occurred in 22.4% (95% CI: 16.4%, 29.7%) of devices tested, including 19.1% among Omron devices and 27.6% among non-Omron devices (P = 0.23). No patient characteristics were associated with agreement failure. CONCLUSIONS: Over one-fifth of home devices did not agree based on the AMA SMBP device accuracy protocol. These findings confirm the importance of office-based device comparisons to ensure the accuracy of home BP monitoring.

Inter-arm blood pressure difference in post-stroke patients with hemiparesis.

The aim of this study was to investigate that inter-arm blood pressure (BP) difference (IAD) and reference arm in 420 post-stroke patients with hemiparesis. Synchronous bilateral-arm BP was measured with two automatic BP devices, and the systolic BP difference of ≥10 mm Hg was recorded as increased sIAD. The arm with higher systolic BP (SBP) was assigned as the reference arm. Our results showed that the prevalence of sIAD was 18.1% in the total group. The paretic arms had similar mean SBP levels (133.6±18.4 vs. 133.8±18.4 mm Hg, NS) and DBP (77.8±11.5 vs. 77.2±10.9 mm Hg, NS) as compared with the unaffected arms. The detection rate of hypertension or uncontrolled hypertension on the SBP values of the reference arm was higher than that on the unaffected arm (41.8% vs. 36.3%). It is concluded that in the post-stroke patients with hemiparesis in the rehabilitation period, the prevalence of sIAD ≥10 mmHg was relatively higher, and using the unaffected arm, rather than the unaffected arm, for BP measurement could induce correctly detection of hypertension.

New Perspectives on Non-invasive Blood Pressure Measurement.

Noninvasive blood pressure (NIBP) devices are calibrated against validated auscultation sphygmomanometers using Korotkoff sounds. This study aimed to investigate the timing of Korotkoff sounds in relation to pulse appearance in the brachial artery and values of intra-arterial blood pressure. Experiments were carried out on 15 participants, (14 males, 64.3 ± 10.4 years; one female, 86 yo), undergoing coronary angiography. A conventional occluding cuff, with a microphone for Korotkoff sounds, was placed on the upper arm (on the brachial artery). Intra-arterial blood pressure (IABP) was measured below the cuff with a fluid-filled catheter inserted via the radial artery and an external transducer. Finger photoplethysmography was used to measure brachial pulse wave velocity (PWV). Korotkoff sounds were processed electronically and custom algorithms identified the cuff pressure (CP) at which the first and last Korotkoff sounds were heard. PWV and max slope of the IABP pressure pulse were recorded to estimate arterial stiffness. The brachial artery closed at a CP of 132.0 ± 17.1 mmHg. Systolic and diastolic blood pressure (SBP and DBP) were 147.6 ± 14.3 and 72.7 ± 10.1 mmHg; mean pressure (MP, 100.1 ± 10.4 mmHg) was similar to MP derived from the peak of the oscillogram (98.5 ± 13.6 mmHg). Difference between IABP and CP recorded at first and last occurrence of Korotkoff sounds were, SBP: 19.0 ± 8.3 (range 2-29) mmHg, DBP: 4.0 ± 4.3 (range 2-12) mmHg. SBP derived from the onset of Korotkoff sounds can underestimate IABP by up to 19 mmHg. Since Korotkoff sounds are the recommended method mandated by the universal standard for the validation of blood pressure measuring devices, these errors are propagated through to all NIBP measurement devices irrespective of whether they use auscultatory or oscillometric methods.

Sphygmomanometer Dynamic Pressure Measurement Using a Condenser Microphone.

There is a worldwide need to improve blood pressure (BP) measurement error in order to correctly diagnose hypertension. Cardiovascular diseases cause 17.9 million deaths annually and are a substantial monetary strain on healthcare. The current measurement uncertainty of 3 mmHg should be improved upon. Dynamic pressure measurement standards are lacking or non-existing. In this study we propose a novel method of measuring air pressure inside the sphygmomanometer tubing during BP measurement using a condenser microphone. We designed, built, and tested a system that uses a radiofrequency (RF) modulation method to convert changes in capacitance of a condenser microphone into pressure signals. We tested the RF microphone with a low-frequency (LF) sound source, BP simulator and using a piezoresistive pressure sensor as a reference. Necessary tests were conducted to assess the uncertainty budget of the system. The RF microphone prototype has a working frequency range from 0.5 Hz to 280 Hz in the pressure range from 0 to 300 mmHg. The total expanded uncertainty (k = 2, p = 95.5%) of the RF microphone was 4.32 mmHg. The proposed method could establish traceability of BP measuring devices to acoustic standards described in IEC 61094-2 and could also be used in forming dynamic BP standards.

Current and Developing Technologies for BP Monitoring.

PURPOSE OF REVIEW: To discuss new and emerging technologies for blood pressure measurement and monitoring, including the limitations of current blood pressure measurement techniques, hopes for new device technologies, and the current barriers impeding change in this space. RECENT FINDINGS: A number of new cuffless devices are being developed and poised to emerge on the marketplace in coming years. There are several different types of technologies and sensors currently under study. New guidelines for validation of cuffless blood pressure devices have recently been developed in anticipation of this change. The current standards for blood pressure device validation are specific to cuff-based technology and are insufficient for validating devices with cuffless-based technologies. In anticipation of a number of new cuffless technologies coming to market in the coming years, three sets of standards have been developed and published in recent years to address this gap.

The Promise and Illusion of Continuous, Cuffless Blood Pressure Monitoring.

PURPOSE OF REVIEW: Blood pressure (BP) fluctuations outside of clinic are increasingly recognized for their role in the development of cardiovascular disease, syncope, and premature death and as a promising target for tailored hypertension treatment. However, current cuff-based BP devices, including home and ambulatory devices, are unable to capture the breadth of BP variability across human activities, experiences, and contexts. RECENT FINDINGS: Cuffless, wearable BP devices offer the promise of beat-to-beat, continuous, noninvasive measurement of BP during both awake and sleep periods with minimal patient inconvenience. Importantly, cuffless BP devices can characterize BP variability, allowing for the identification of patient-specific triggers of BP surges in the home environment. Unfortunately, the pace of evidence, regulation, and validation testing has lagged behind the pace of innovation and direct consumer marketing. We provide an overview of the available technologies and devices for cuffless BP monitoring, considerations for the calibration and validation of these devices, and the promise and pitfalls of the cuffless BP paradigm.

Technical evaluation of a simulator for accurate reproduction of oscillometric blood pressure pulses, providing traceability for automated oscillometric sphygmomanometers.

Oscillometric blood pressure measurement devices are not directly traceable to primary standards. Currently, device accuracy is measured by comparison between a sample device and reference measurements in a clinical trial. We researched in this study the potential for an alternative evaluation with a simulator. Our research simulator was studied for repeatability and accuracy in delivering simulated blood pressure pulses. Clinical cuff pressure measurements were obtained, along with simultaneous recordings of oscillometric pulse waveforms, spanning the clinical range of cuff pressures, pulse intervals and pulse shapes. Oscillometric pulse peak amplitudes ranged from 1.1 to 3.6 mmHg. Simulated repeatability results showed an average Standard Deviation (SD) for pulse peaks of 0.018 mmHg; 1.0% of peak amplitudes. Comparing simulated pulse shapes, the average repeat SD was 0.015 mmHg; 0.8% of the normalised pulse shapes. The simulated accuracy results had a mean error of - 0.014 ± 0.042 mmHg with a mean accuracy of 97.8%. For pulse shape the corresponding values were - 0.104 ± 0.071 mmHg with a mean accuracy of 95.4%. The correlation between the reference and simulated pulse shapes ranged from 0.991 to 0.996 (all p < 0.00003), with a mean 0.994. We conclude that oscillometric pulses can be reproduced with high repeatability and high accuracy with our research simulator. The extended uncertaintyU(psim) = 0.3 mmHg for the simulated pulses is dominated by the uncertainty (64%) of the clinical reference data. These results underpin the potential of the simulator to become a secondary standard for millions of oscillometric sphygmomanometers.