title: Repeatability of central aortic blood pressures measured non-invasively using radial artery applanation tonometry and peripheral pulse wave analysis.
abstract: OBJECTIVE
  To estimate the repeatability of radial pulse wave analysis (PWA) in measuring central systolic and diastolic blood pressures (cSBP/cDBP), pulse pressure (cPP), augmentation pressure (cAP) and pulse pressure amplification (PPA).
  
  
  METHODS
  After 15 min supine rest, 20 ambulant patients (aged 27-82 years; four female) underwent four SphygmoCor PWA measurements on a single occasion. Two nurses independently undertook two measurements in alternate order, blind to their colleague's measurements. Analysis was by Bland-Altman limits of agreement (LOA).
  
  
  RESULTS
  Heart rate and brachial blood pressure (BP) were stable during assessment. Based on the average of two PWA measurements between-observer differences (LOA, mean difference +/- 2SD) were small (cSBP 1.5 +/- 10.9 mmHg; cDBP 0.4 +/- 5.2 mmHg; cAP 0.5 +/- 4.5 mmHg; cPP 1.1 +/- 10.5 mmHg; PPA -0.5% +/- 5.6%). Between-observer differences were much greater for single/initial PWA measurement (cSBP 3.6 +/- 15.9 mmHg; cDBP 2.8 +/- 8.8 mmHg; cAP 0.7 +/- 5.8 mmHg; cPP 0.8 +/- 13.6 mmHg; PPA -1.2 +/- 9.4%). Within-observer LOA were very similar for both nurse A (cSBP -4.2 +/- 14.1 mmHg; cDBP -4.6 +/- 13.1 mmHg; cAP -0.4 +/- 4.4 mmHg; cPP 0.5 +/- 11.0 mmHg; PPA 0.7% +/- 9.0%) and nurse B (cSBP 0.0 +/- 12.1 mmHg; cDBP 0.2 +/- 8.5 mmHg; cAP -0.1 +/- 4.4 mmHg; cPP -0.2 +/- 11.9 mmHg; PPA -0.7% +/- 10.6%).
  
  
  CONCLUSIONS
  Non-invasive assessment of central aortic pressures using PWA on a single occasion is highly repeatable in ambulant patients even when used by relatively inexperienced staff.
authors.affiliation: Department of Public Health, University of Aberdeen Medical School, Polwarth Building at Foresterhill, Aberdeen, UK. mike.crilly@abdn.ac.uk
authors.forename: Mike
authors.initials: M
authors.lastname: Crilly
authors.forename: Christoph
authors.initials: C
authors.lastname: Coch
authors.forename: Margaret
authors.initials: M
authors.lastname: Bruce
authors.forename: Hazel
authors.initials: H
authors.lastname: Clark
authors.forename: David
authors.initials: D
authors.lastname: Williams
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged; D015588:Observer Variation; D011673:Pulsatile Flow; D017534:Radial Artery / Q000502:physiology; D015203:Reproducibility of Results