Abstract 088: Comparison Of 24-hour Blood Pressure Tracking Between A Commercially Available Cuffless Wearable Device And Standard Ambulatory Monitoring

Abstract

Introduction: Cuffless blood pressure (BP) monitoring offers great potential in assessing 24-hour BP without user disturbance. Despite the myriad of commercially available cuffless BP devices, 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). Hypothesis: A commercially available cuffless wearable BP device, previously demonstrated to have good accuracy for seated BP, can track 24-hour BP changes as well as standard ABPM. Methods: We included 45 individuals (36 hypertensive, 15 female, age 58±14 years [mean±SD]) in two centres (Perth, Australia; Athens, Greece). Participants used a cuffless wearable BP device (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: Compared to ABPM, the cuffless device reported higher 24-hour systolic BP (SBP) by 6.8 mmHg, 95% CI [3.7, 9.7], higher daytime SBP by 3.8 mmHg [1.0, 6.7], and higher nighttime SBP by 17.5 mmHg [13.6, 21.4] (all p≤0.01). Cuffless 24-hour diastolic BP (DBP) was comparable with ABPM (difference 1.2 mmHg, 95% CI [-1.0, 3.5]), as was daytime DBP (difference -0.8 mmHg, [-3.0, 1.3]) (both p≥0.27), but nighttime DBP was higher by 9.2 mmHg, [6.3, 12.2] (p<0.001). Nighttime dip in SBP (-5.1 mmHg, 95% CI [-13.7, 3.6]) and DBP (-3.8 mmHg, [-11.6, 4.2]) as measured by the cuffless device were substantially less than ABPM (SBP dip: -18.0 mmHg, [-35.5, -1.2]; DBP dip: -13.8 mmHg, [-27.2, -0.8]). The cuffless device identified 44 nighttime non-dippers (defined as a relative dip < 10%) for SBP and 42 non-dippers for DBP, compared to 10 non-dippers for both SBP and DBP as identified by ABPM (both comparisons p<0.001). Conclusions: A commercially available cuffless wearable BP device was unable to adequately track diurnal BP variation and considerably overestimated average SBP over 24 hours as compared to standard ABPM.