title: Pulse wave analysis is a reproducible technique for measuring central blood pressure during hemodynamic perturbations induced by exercise.
abstract: BACKGROUND
  Central blood pressure (BP) and markers of wave reflection (augmentation index; AIx) measured by radial tonometry have prognostic value independent from brachial BP. The measurement of the central waveform is increasingly used during altered hemodynamics, including exercise, but reliability of the test has not been reported under changed loading conditions. This study aimed to test the technique's reproducibility during major hemodynamic perturbations induced by exercise.
  
  
  METHODS
  Radial waveforms were recorded (SphygmoCor) in 28 healthy subjects (aged 53 +/- 11 years) at rest, during submaximal exercise (cycling at 50, 60, and 70% of maximal age-predicted heart rate (HR)) and immediately after maximal treadmill exercise on two occasions separated by 9 +/- 5 days. Data were compared between testing days. Waveforms were calibrated with brachial BP measured using a mercury sphygmomanometer. Pulse pressure amplification (PPAmp) was defined as the ratio of brachial to central pulse pressure.
  
  
  RESULTS
  There was very good reproducibility between visits at all exercise intensities for all waveform measures, including AIx, central pulse pressure, and PPAmp (intraclass correlations at 50% exercise were 0.93, 0.89, and 0.89, respectively; P < 0.001). The mean difference between tests at this intensity was 0 +/- 4% for AIx, 4 +/- 6 mm Hg for central pulse pressure, and -0.02 +/- 0.09 for PPAmp. There were no significant differences between visits for HR, PPAmp, or AIx at rest or with exercise (P > 0.05 for all).
  
  
  CONCLUSIONS
  Radial tonometry is a reproducible technique for measurement of central waveform indices during perturbations induced by exercise. It should, therefore, be suitable for use in intervention studies in which hemodynamics are altered.
authors: Department of Medicine, Princess Alexandra Hospital, Brisbane, Australia.
authors: David J
authors: DJ
authors: Holland
authors: Julian W
authors: JW
authors: Sacre
authors: Sarah J
authors: SJ
authors: McFarlane
authors: Jeffrey S
authors: JS
authors: Coombes
authors: James E
authors: JE
authors: Sharman
mesh_terms: D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011674:Pulse; D012016:Reference Values; D015203:Reproducibility of Results