Noninvasive validation of central and peripheral augmentation index estimated by a novel wrist-worn tonometer

The validation of new blood pressure devices with easier use and more rapid data collection may facilitate the incorporation of these measures into clinical practice. We analyze the reliability and validity of Pulse Wave Analysis as reported by a novel wrist-worn device, easy and quick to use, comparing central and peripheral augmentation index (AIx) with the same measures from the SphygmoCor. Additionally, we analyzed clinical relevance through the association of the Pulse Wave Analysis, as reported by a novel wrist-worn device, with other cardiovascular parameters.

Cross-sectional study including 254 participants. Mean age was 51.9 ± 13.4 years and 53% were women.

peripheral AIx (PAIx) and central AIx (CAIx) by the wrist-worn device and SphygmoCor (MM3); carotid-femoral (cf) pulse wave velocity (PWV) by SphygmoCor (MM3); cardioankle-vascular index (CAVI), ankle-brachial index (ABI) and brachial-ankle (ba) PWV by the Vasera device and carotid-intima media thickness (IMT) by ultrasonography.

Intra-observer intra-class correlation coefficient (ICC) for PAIx was 0.886 (95% CI 0.803-0.934) and for CAIx 0.943 (95% CI 0.901-0.968) with Bland Altman limits of agreement -0.75 (-23.8 to 21.8) and 0.08 (-15.7 to 15.9), respectively. Inter-observer ICC for PAIx was 0.952 (95% CI 0.915-0.972) and CAIx 0.893 (95% CI 0.811-0.939) with limits of agreement -0.45 (-13.7 to 12.8) and 0.43 (-17.7 to 18.5), respectively. Comparing the wrist-worn device with SphygmoCor, the ICC was 0.849 (95% CI 0.798-0.887) for PAIx, and 0.783 (95% CI 0.711-0.838) for CAIx. In Bland-Altman, limits of agreement for PAIx 1.03 (-20.67 to 22.73), and for CAIx -2.14 (-24.79 to 20.50). PAIx and CAIx, from the wrist-worn device, correlated with age, CAVI, ABI, baPWV, cfPWV, IMT, glomerular filtration and cardiovascular risk.

AIx measurements by wrist-worn device shows a good intra-observer and inter-observer reliability, inter-device noninvasive reliability and validity when compared with SphygmoCor, and clinical relevance by association with measures of vascular structure and function, end-organ damage and cardiovascular risk.

Clinicaltrials.gov NCT02623894; https://clinicaltrials.gov/ct2/show/NCT02623894.