title: Comparison of noninvasive assessments of central blood pressure using general transfer function and late systolic shoulder of the radial pressure wave.
abstract: BACKGROUND
  Central systolic blood pressure (cSBP) can be derived by the general transfer function of the radial pressure wave, as used in the SphygmoCor device, or by regression equation from directly measured late systolic shoulder of the radial pressure wave (pSBP2), as used in the Omron HEM-9000AI device. The aim of this study was to compare the SphygmoCor estimates of cSBP with 2 estimates of cSBP provided by the Omron HEM-9000AI (cSBP, pSBP2) in a large cohort of the white population.
  
  
  METHODS
  In 391 patients aged 52.3±13.5 years (46% men) from the Czech post-MONICA Study, cSBP was measured using the SphygmoCor and Omron HEM-9000AI devices in random order.
  
  
  RESULTS
  Omron cSBP and pSBP2 were perfectly correlated (r = 1.0; P < 0.0001). There was a strong correlation (r = 0.97; P < 0.0001) between Omron and SphygmoCor cSBP estimates, but Omron estimate was 13.1±4.7mm Hg higher than SphygmoCor cSBP. On the other hand, Omron pSBP2 strongly correlated with SphygmoCor cSBP (r = 0.97; P < 0.0001) and was 1.7±4.2mm Hg lower than SphygmoCor cSBP. In multivariable analysis, anthropometric and cardiovascular risk factors explained only 10% of the variance of the cSBP difference between devices while explaining 52% of the systolic blood pressure amplification variance.
  
  
  CONCLUSIONS
  Estimation of cSBP based on the late systolic shoulder of the radial wave provides a comparable accuracy with the validated general transfer function. When comparing Omron HEM-9000AI and SphygmoCor estimates of cSBP, Omron pSBP2 should be used. The difference between both devices in cSBP may be explained by differences in calibration.
authors.affiliation: Center for Cardiovascular Prevention, Charles University in Prague, First Faculty of Medicine, and Thomayer Hospital, Prague, Czech Republic.
authors.forename: Peter
authors.initials: P
authors.lastname: Wohlfahrt
authors.forename: Alena
authors.initials: A
authors.lastname: Krajcoviechová
authors.forename: Jitka
authors.initials: J
authors.lastname: Seidlerová
authors.forename: Otto
authors.initials: O
authors.lastname: Mayer
authors.forename: Jan
authors.initials: J
authors.lastname: Filipovsky
authors.forename: Renata
authors.initials: R
authors.lastname: Cífková
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation; D001916:Brachial Artery / Q000502:physiology; D002318:Cardiovascular Diseases / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013599:Systole
keywords: applanation tonometry; blood pressure; central systolic blood pressure; generalized transfer function; hypertension; radial pulse wave; radial second systolic pressure.