Comparison of the SphygmoCor and Omron devices in the estimation of pressure amplification against the invasive catheter measurement

Abstract

We previously tested the accuracy of the SphygmoCor and Omron HEM-9000AI devices in the estimation of central blood pressure. In the present study, we investigated these two devices in the estimation of central-to-brachial pressure amplification against the invasive catheter measurement. In 33 individuals undergoing cardiac catheterization, we measured central blood pressure simultaneously by the invasive catheter and each of the two noninvasive devices and brachial blood pressure by the invasive catheter and an automated oscillometric blood pressure monitor of the Omron device. Pressure amplification was calculated as central-to-brachial systolic pressure difference and pulse pressure difference and ratio. The agreement between each of these two noninvasive devices and the invasive catheter was evaluated using the Student's t-test, intraclass correlation analysis, and the Bland-Altman method. The mean central-to-brachial systolic pressure difference and pulse pressure difference and ratio estimated by Omron were significantly lower than those measured by the catheter (P < 0.001), whereas no difference was observed for SphygmoCor (P ≥ 0.07). Nonetheless, the intraclass correlation coefficients for systolic pressure difference and pulse pressure difference and ratio between the noninvasive and invasive catheter measurements were similar for the two devices, being 0.11 (P = 0.56), 0.38 (P = 0.03), and 0.40 (P = 0.02), respectively, for SphygmoCor, and 0.15 (P = 0.41), 0.23 (P = 0.20), and 0.53 (P = 0.002), respectively, for Omron. If the invasive catheter measurement would be considered as standard, the two noninvasive devices have similar accuracy in the estimation of pressure amplification, but apparently require device-specific criteria for diagnosis. Pulse pressure ratio seems to be a more consistent measure of central-to-brachial pressure amplification.