Validation of ring-type cuffless blood pressure (BP) monitoring device for detecting awake-asleep BP variations compared to ambulatory BP monitoring device.

We evaluated the accuracy of a ring-type cuffless BP device (CART BP Pro) in detecting awake-asleep BP changes compared to conventional 24-h ambulatory BP monitoring (ABPM), following the validation protocol recommended by the European Society of Hypertension (ESH). Among 84 recruited patients, 35 were selected to satisfy ESH recommendations: 30% (n = 11) with systolic BP (SBP) ≥ 130 mmHg and diastolic BP (DBP) ≥ 80 mmHg and 30% (n = 11) with SBP < 120 mmHg and DBP < 70 mmHg. The remaining 40% (n = 13) were included sequentially based on recruitment order. CART BP Pro was calibrated at least one day prior to simultaneous monitoring with ABPM. Participants simultaneously wore both devices on the non-dominant arm for 24 h. Mean SBP/DBP values and awake-asleep BP changes were compared. Awake-asleep SBP/DBP changes were 15.61 ± 8.74/11.35 ± 6.22 mmHg (ABPM) and 13.87 ± 9.04/11.44 ± 8.62 mmHg (CART BP Pro). Differences in mean awake-asleep BP changes were -1.74 ± 6.47 mmHg (SBP) and 0.08 ± 5.84 mmHg (DBP). Correlation analysis showed clinically significant correlation for both SBP and DBP changes (r = 0.736, p < 0.01). Bland-Altman plots showed acceptable agreement with a mean difference and 95% limits of agreement of -1.74 (-14.42, 10.94) mmHg for SBP and 0.08 (-11.37, 11.53) mmHg for DBP. For four-category dipping classification, CART BP Pro showed moderate agreement with ABPM (weighted κ = 0.58). In conclusion, CART BP Pro showed a meaningful level of agreement with ABPM in detecting awake-asleep BP changes. As this addressed only the awake/asleep test of the ESH protocol, the device cannot yet replace conventional 24-h ABPM pending completion of the remaining validation tests.