Patent ID: 9730594
Date: 2017-08-15
CPC Classifications: A61B

Claim:
1. An arterial-wall stiffness evaluation system comprising: a cuff to be attached to a part of a living body: a pressure sensor for detecting pressure in the cuff, and a control section including a cuff-pressure control section for controlling the pressure in the cuff to be increased or decreased to a predetermined value, based on a value detected by the pressure sensor; and a data processing section for calculating, based on pulse waves detected by the pressure sensor, pulse-wave amplitudes of cuff-pressure pulse waves and blood-pressure pulse waves, and for evaluating arterial-wall stiffness based on the pulse-wave amplitudes thus calculated, i) obtaining respective ratios between amplitudes of extracted cuff-pressure pulse waves and corresponding pulse pressures in respective pulse-wave zones including a transmural pressure of P applied to a vascular wall and determining an average value of the respective ratios as a differential value corresponding to the transmural pressure of P applied to a vascular wall, wherein a pulse-wave zone is a zone on an axis representing the transmural pressure which zone corresponds to an amplitude of a blood-pressure pulse wave at a certain time point; ii) performing the step i) twice or more so as to obtain a plurality of average values each being the average value obtained in the step i), and obtaining a set of points respectively corresponding to the plurality of average values; iii) fitting a curve determined by a differentiated arctan function to the set of points; iv) determining the arterial-wall stiffness according to a parameter of the differentiated arctan function; and v) outputting said arterial-wall stiffness to a user.