title: Comparison of the SphygmoCor and Omron devices in the estimation of pressure amplification against the invasive catheter measurement.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Centre for Epidemiological Studies and Clinical Trials, The Shanghai Institute of Hypertension, Shanghai, China.
authors.forename: Feng-Hua
authors.initials: FH
authors.lastname: Ding
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Rui-Yan
authors.initials: RY
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ji-Guang
authors.initials: JG
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation* / Q000379:methods; D006328:Cardiac Catheterization / Q000379:methods*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D019722:Sphygmomanometers