BLOOD PRESSURE FROM THE OPTICAL AKTIIA BRACELET: A ONE MONTH VALIDATION STUDY USING AN ADAPTED ISO81060-2 PROTOCOL

Abstract

Objective: Cuffless Blood Pressure (BP) monitoring is an emerging new technology with the potential to improve patients’ experience while providing physicians with a more comprehensive set out of office blood pressure measurements. The Aktiia Bracelet is a non-invasive BP monitor intended to measure optical photo-plethysmographic signals on the wrist and to calculate Systolic (SBP) and Diastolic (DBP) values using a pulse wave analysis technique. The Aktiia Bracelet requires an initialization procedure to be performed once per month. The objective of this study (NCT04027777) was to validate the accuracy and precision of the Aktiia Bracelet in the sitting position and over a period of one month. Design and method: A representative cohort of male and female, hypotensive, normotensive and hypertensive participants, aged 21 to 65 years, presenting different skin pigmentations (Fitzpatrick scale from 1 to 5) and different hair follicle densities were included. Four visits were scheduled for each participant. After initialization, the optical signals measured from the Aktiia Bracelet were used to calculate SBP and DBP values and were compared to auscultatory measurements obtained simultaneously by two double-blinded trained observers. The clinical investigation (including data analysis) was conducted by adapting the methods of ISO81060-2 to the requirements of a multi-visit validation of a cuffless device. Results: Data from a total of 91 participants in sitting position were included in the current analysis. For SBP, a mean difference (± SD) of 0.46 ± 7.74 mmHg between reference and Aktiia Bracelet values was found (criterion 1), with measured standard deviation of the averaged differences per subject of 3.9 mmHg (criterion 2). For DBP, a mean difference (± SD) of 0.39 ± 6.86 mmHg between reference and Aktiia Bracelet values was found, with measured standard deviation of the averaged differences per subject of 3.6 mmHg. Bland-Altman plots for SBP and DBP are shown in the following figure. Conclusions: The Aktiia Bracelet fulfilled the requirements of criterion 1 and 2 of the adapted ISO81060-2 protocol. The use of the Aktiia Bracelet could facilitate widespread use of accurate, longitudinal and easy out-of-office blood pressure measurements.