title: Photoplethysmography, an easy and accurate method for measuring ankle brachial pressure index: can photoplethysmography replace Doppler?
abstract: OBJECTIVE
  To assess the accuracy of ankle brachial pressure index (ABPI) assessed by photoplethysmography (PPG) compared with continuous wave Doppler (CW-Doppler).
  
  
  METHODS
  Ankle brachial pressure index was measured in a standard manner using both PPG and Doppler probes. For PPG-ABPI, a PPG probe was placed on the index finger and great toe, and a microcomputer determined the ABPI. These values were compared with the ABPI measured manually using an 8-MHz Doppler probe. Correlation and agreement between PPG and Doppler ABPI were assessed by Lin's correlation coefficient and Bland-Altman plots.
  
  
  RESULTS
  In all, 133 claudicants were assessed. There was a strong correlation between the 2 ABPI methods (beta = .79 and 95% limits of agreement of -0.23 to 0.24).
  
  
  CONCLUSIONS
  Measuring ABPI automatically using the PPG technique is an effective alternative for Doppler ABPI. PPG-ABPI is completely objective, fast, and accurate.
authors.affiliation: Norfolk and Norwich University Hospital NHS Trust, Vascular Surgery Unit, UK. nkh950@yahoo.com
authors.forename: Nader
authors.initials: N
authors.lastname: Khandanpour
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Armon
authors.forename: Barbara
authors.initials: B
authors.lastname: Jennings
authors.forename: Allan
authors.initials: A
authors.lastname: Clark
authors.forename: Felicity J
authors.initials: FJ
authors.lastname: Meyer
mesh_terms: D000368:Aged; D000842:Ankle / Q000098:blood supply*; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000295:instrumentation / Q000379:methods*; D001916:Brachial Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007383:Intermittent Claudication / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008838:Microcomputers; D008875:Middle Aged; D017156:Photoplethysmography / Q000295:instrumentation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler