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. 2021 Oct 19;11(1):20644.
doi: 10.1038/s41598-021-99294-w.

Validation of the optical Aktiia bracelet in different body positions for the persistent monitoring of blood pressure

Josep Sola  1 , Anna Vybornova  2 , Sibylle Fallet  2 , Erietta Polychronopoulou  3 , Arlene Wurzner-Ghajarzadeh  3 , Gregoire Wuerzner  3
Affiliations

Validation of the optical Aktiia bracelet in different body positions for the persistent monitoring of blood pressure

Josep Sola et al. Sci Rep. .

Abstract

The diagnosis of hypertension and the adjustment of antihypertensive drugs are evolving from isolated measurements performed at the physician offices to the full phenotyping of patients in real-life conditions. Indeed, the strongest predictor of cardiovascular risk comes from night measurements. The aim of this study was to demonstrate that a wearable device (the Aktiia Bracelet) can accurately estimate BP in the most common body positions of daily life and thus become a candidate solution for the BP phenotyping of patients. 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 4 weeks according to an extended ISO 81060-2 protocol. After initializing on day one, 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. This study demonstrates that a wearable device can accurately estimate BP in the most common body positions compared to auscultation, although precision varies across positions. While wearable persistent BP monitors have the potential to facilitate the identification of individual BP phenotypes at scale, their prognostic value for cardiovascular events and its association with target organ damage will need cross-sectional and longitudinal studies. Deploying this technology at a community level may be also useful to drive public health interventions against the epidemy of hypertension.

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Conflict of interest statement

J.S., A.V. and S.F. are employees of Aktiia SA. G.W. serves as a consultant for Aktiia SA. All other authors report no potential conflicts of interest.

Figures

Figure 1
Figure 1
The Aktiia 24/7 BP monitor is a wearable device that persistently measures optical signals on the skin vasculature of the wrist and displays day and night BP values on a companion smartphone application. The Aktiia Bracelet is a CE-marked class IIa medical device.
Figure 2
Figure 2
Schematic representation of the protocol designed to evaluate the performance of a cuffless BP monitor intended to be used in 24/7 environments. At each visit, assessments involving the reference device and the device under test are performed in varying body positions such as sitting, lying and standing positions, and after exercise. Visits are further repeated in order to test the stability of the device.
Figure 3
Figure 3
Experimental set up of the required equipment to investigate the performance of a BP monitor intended to be used in 24/7 environments. Reference BP values are obtained by a validated hybrid sphygmomanometer and auscultation with a dual-head stethoscope. Changes in auscultation values with different body positions are controlled by the continuous measurements of an ipso-lateral volume-clamp device. Measurements by the device under test are performed in the contra-lateral arm.
Figure 4
Figure 4
Implemented data analysis controlling the reliability of auscultatory BP measurements by means of a reference control (volume-clamp measurements), and further identifying assessments for which quality of optical signals is sufficient to execute Pulse Wave Analysis routines of the algorithms of Aktiia Bracelet. The number of available subjects and recording at each step is reported.
Figure 5
Figure 5
Acceptance rate of the Pulse Wave Analysis algorithms of Aktiia bracelet for each body position: percentage of time for which the recorded optical signals could be analyzed to generate a SBP and a DBP value.
Figure 6
Figure 6
Scatter plots and Bland Altman plots comparing Aktiia BP readings against reference auscultatory readings for sitting and lying positions.
Figure 7
Figure 7
Scatter plots and Bland Altman plots comparing Aktiia BP readings against reference auscultatory readings for standing and all positions.
Figure 8
Figure 8
Introduction to the concept of BP phenotyping using persistent BP monitoring at the wrist, enabling a new category of studies and programs to investigate how longitudinal 24/7 measurements can improve cardiovascular outcomes at both individual and community levels.
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References

    1. Unger T, et al. 2020 International Society of Hypertension global hypertension practice guidelines. Hypertension. 2020;75(6):1334–1357. doi: 10.1161/HYPERTENSIONAHA.120.15026. - DOI - PubMed
    1. Williams B, et al. 2018 ESC/ESH guidelines for the management of arterial hypertension. Eur. Heart J. 2018;39(33):3021–3104. doi: 10.1093/eurheartj/ehy339. - DOI - PubMed
    1. Whelton PK, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: A report of the American College of Cardiology/American Heart Association task force on clinical practice guidelines. Hypertension. 2018 doi: 10.1161/HYP.0000000000000065. - DOI - PubMed
    1. Geddes L. Handbook of Blood Pressure Measurement. Springer; 1991.
    1. Burnier M, Wuerzner G. What is the hypertension ‘phenotype’? Curr. Cardiovasc. Risk Rep. 2015;9(3):9. doi: 10.1007/s12170-015-0438-5. - DOI

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