title: Automatic ankle pressure measurements using PPG in ankle-brachial pressure index determination.
abstract: OBJECTIVE
  To evaluate a new technique using a photoplethysmographic (PPG) probe for automatic ankle pressure measurements.
  
  
  METHODS
  Comparative study on two techniques for ankle pressure measurement.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Thirty-five patients with leg arterial disease and eight healthy volunteers. Ankle-brachial indices (ABPI) were measured using conventional CW Doppler technique and PPG-based prototype equipment for the ankle pressure recordings.
  
  
  METHODS
  ABPIs calculated from CW Doppler and PPG ankle pressure measurements. The PPG signals were analysed both by visual judgement and by a software based, automatic algorithm.
  
  
  RESULTS
  The mean difference between ABPIs calculated from CW Doppler recordings and PPG (visual analysis) was -0.01 (limits of agreement (+/-two standard deviations) +0.16 to -0.19). The correlation coefficient was 0.93. When the algorithm was used, the mean difference (CW Doppler-PPG) was 0.05 (limits of agreement 0.28 to -0.18, r=0.89).
  
  
  CONCLUSIONS
  The PPG method is a promising technique with an inherent potential for automatisation of the ankle pressure measurements, thereby reducing the observer-dependency in ABPI recordings.
authors.affiliation: Department of Cardiovascular Surgery and Anaesthesia, University Hospital, Linköping, Sweden. bjorn.jonsson@lio.se
authors.forename: B
authors.initials: B
authors.lastname: Jönsson
authors.forename: C
authors.initials: C
authors.lastname: Laurent
authors.forename: M
authors.initials: M
authors.lastname: Eneling
authors.forename: T
authors.initials: T
authors.lastname: Skau
authors.forename: L-G
authors.initials: LG
authors.lastname: Lindberg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000842:Ankle / Q000098:blood supply*; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000503:physiopathology; D007511:Ischemia / Q000503:physiopathology; D008875:Middle Aged; D017156:Photoplethysmography / Q000295:instrumentation / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D018615:Ultrasonography, Doppler, Color; D018616:Ultrasonography, Doppler, Duplex