COMPARISON OF 24-HOUR BLOOD PRESSURE MONITORING USING THE CUFFLESS DEVICE, CART BP, AND CONVENTIONAL AMBULATORY BLOOD PRESSURE MONITORING

Objective: Cuffless blood pressure (BP) monitoring devices, such as the CART BP, offer a minimally invasive alternative to conventional ambulatory BP monitoring (ABPM). CART BP, a wearable ring-type device, uses photoplethysmography (PPG) to measure BP continuously, but its clinical applicability requires evaluation against standard 24-hour ABPM. We aimed to evaluate the feasibility and accuracy of 24-hour BP measurement using CART BP compared with the conventional ABPM, focusing on diurnal BP changes.Design and method: This study included 40 participants, with 33 completing the protocol. Participants wore both CART BP and ABPM devices on the same (non-dominant) arm for 24 hours. CART BP recorded BP every minute, while ABPM took readings at 20-minute intervals during the day and 30-minute intervals at night. Measurements from CART BP were compared with ABPM using correlation analyses and mean differences, and the impact of calibration positions was assessed. Results: CART BP generated approximately 10 times more readings than ABPM (754.2 ± 173.5 vs. 60.7 ± 4.6). Strong correlations were observed between CART BP and ABPM for systolic BP (SBP, r=0.886) and diastolic BP (DBP, r=0.843; both p<0.001). 24-hour BP measured by CART BP were shown significantly lower values, especially for daytime DBP (-5.9 ± 7.3 mmHg, p<0.001) and nighttime BP dips (SBP: 3.7 ± 5.6 mmHg vs. 7.4 ± 8.5 mmHg; DBP: 2.4 ± 2.8 mmHg vs. 6.3 ± 6.5 mmHg). It also classified more participants as DBP non-dippers (75.8% vs. 42.4%, p=0.003). Calibration strategies (multiple-position vs. sitting-only) did not significantly affect results. Conclusions: CART BP shows promise as a cuffless device for 24-hour BP monitoring, capturing more frequent data than ABPM. However, it underestimates BP values and demonstrates limited accuracy in tracking BP variability,