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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.