Evaluation of arterial stiffness by finger-toe pulse wave velocity: optimization of signal processing and clinical validation

J Hypertens. 2017 Aug;35(8):1618-1625. doi: 10.1097/HJH.0000000000001371.


Background: Carotid-femoral pulse wave velocity (PWV) (cf-PWV) is the gold standard for measuring aortic stiffness. Finger-toe PWV (ft-PWV) is a simpler noninvasive method for measuring arterial stiffness. Although the validity of the method has been previously assessed, its accuracy can be improved. ft-PWV is determined on the basis of a patented height chart for the distance and the pulse transit time (PTT) between the finger and the toe pulpar arteries signals (ft-PTT).

Method: The objective of the first study, performed in 66 patients, was to compare different algorithms (intersecting tangents, maximum of the second derivative, 10% threshold and cross-correlation) for determining the foot of the arterial pulse wave, thus the ft-PTT. The objective of the second study, performed in 101 patients, was to investigate different signal processing chains to improve the concordance of ft-PWV with the gold-standard cf-PWV. Finger-toe PWV (ft-PWV) was calculated using the four algorithms.

Results: The best correlations relating ft-PWV and cf-PWV, and relating ft-PTT and carotid-femoral PTT were obtained with the maximum of the second derivative algorithm [PWV: r = 0.56, P < 0.0001, root mean square error (RMSE) = 0.9 m/s; PTT: r = 0.61, P < 0.001, RMSE = 12 ms]. The three other algorithms showed lower correlations. The correlation between ft-PTT and carotid-femoral PTT further improved (r = 0.81, P < 0.0001, RMSE = 5.4 ms) when the maximum of the second derivative algorithm was combined with an optimized signal processing chain.

Conclusion: Selecting the maximum of the second derivative algorithm for detecting the foot of the pressure waveform, and combining it with an optimized signal processing chain, improved the accuracy of ft-PWV measurement in the current population sample. Thus, it makes ft-PWV very promising for the simple noninvasive determination of aortic stiffness in clinical practice.

Publication types

  • Evaluation Study

MeSH terms

  • Adult
  • Aged
  • Algorithms
  • Blood Flow Velocity
  • Case-Control Studies
  • Coronary Artery Disease / physiopathology*
  • Female
  • Fingers / blood supply
  • Humans
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Pulse Wave Analysis* / methods
  • Reproducibility of Results
  • Signal Processing, Computer-Assisted
  • Toes / blood supply
  • Young Adult