Method for determining pulse wave velocity in an artery

Patent metadata

Field	Value
Publication number	US-10959622-B2
Application number	US-201514625110-A
Country	US
Kind code	B2
Filing date	Feb 18, 2015
Priority date	Feb 24, 2014
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

Methods, devices, and systems for determining an estimated pulse wave velocity of an artery of a subject. Embodiment methods may include applying a series of counter pressures, measuring a first parameter related to pulse wave velocity, estimating a second parameter in a model, and determining the estimated pulse wave velocity. The counter pressures may be applied at a set location on the subject over the artery with a pressure device. Each of the counter pressures may be different from one another, applied at the set location, and between zero and a diastolic pressure of the subject. The first parameter may be measured when each of the series of counter pressures is applied. The model may establish a relationship of the first parameter measured to each of the series of counter pressures. The estimated pulse wave velocity may be determined based on the second parameter estimated in the model.

First claim

What is claimed is:

1. A method of determining an estimated pulse wave velocity of an artery of a subject, comprising:
applying a series of counter pressures at a set location on the subject over the artery with a pressure device, wherein each counter pressure of the series of counter pressures is different from one another, applied at the set location, and between zero and a diastolic pressure of the subject, and wherein the applying the series of counter pressures further includes:
measuring, for each counter pressure of the series of counter pressures, a corresponding value of a first parameter related to pulse wave velocity when the respective counter pressure is applied;
determining, with a control unit, after measuring the value of the first parameter corresponding to at least one counter pressure of the series of counter pressures, whether a sufficient number of values have been collected; and
in response to determining a sufficient number of values have not been collected, measuring the value of the first parameter corresponding to an additional counter pressure of the series of counter pressures;

for each model of a predetermined set of models that establishes a relationship of the first parameter to each counter pressure of the series of counter pressures, performing a fitting procedure to determine a fit of the respective model to the measured values of the first parameter, wherein performing the fitting procedure comprises weighting a higher counter pressure more heavily than a lower counter pressure among the series of counter pressures;
selecting a best-fit model from the predetermined set of models based on a result of the fitting procedure performed for each model of the predetermined set of models;
estimating a second parameter using the selected model; and
determining the estimated pulse wave velocity based on the second parameter estimated using the selected model.

2. The method of claim 1 , wherein the series of counter pressures each apply a pressure force in such a way that the pressure force is applied perpendicular to a longitudinal direction of a limb containing the artery.

3. The method of claim 1 , wherein the series of counter pressures are each applied by a tightening band worn by the subject at the set location.

4. The method of claim 3 , wherein measuring, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter includes using two sensors disposed between the tightening band and a portion of skin of the subject.

5. The method of claim 3 , wherein measuring, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter includes using two sensors disposed on a portion of skin of the subject and outside opposed ends of the tightening band.

6. The method of claim 3 , wherein measuring the first value includes using an ultrasound sensor embedded inside the tightening band.

7. The method of claim 1 , wherein measuring, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter includes measuring across a span of less than 20 cm at the set location, wherein the series of counter pressures are each applied along the span.

8. The method of claim 1 , wherein measuring, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter includes using two sensors separated by a span along the artery to measure a transit time of a pulse between the two sensors.

9. The method of claim 1 , wherein measuring, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter includes detecting a distension of the artery over time.

10. The method of claim 1 , wherein measuring, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter includes measuring a first set of parameters.

11. The method of claim 1 , wherein, for each counter pressure of the series of counter pressures, the corresponding value of the first parameter is measured using a technology selected from the group consisting of tonometry, ultrasound, nuclear magnetic resonance, a propagation property of electro-magnetic waves, an optical measurement, and bioelectrical impedance.

12. The method of claim 1 , wherein the second parameter estimated using the selected model includes a second set of parameters.

13. The method of claim 1 , wherein the predetermined set of models is selected from the group consisting of at least one of a predetermined stress-strain relationship of the artery, a Bramwell-Hill equation, an exponential model, and a bi-linear model.

14. A device for determining an estimated pulse wave velocity of an artery of a subject, comprising:
a pressure device configured to apply a series of counter pressures at a set location on the subject over the artery, wherein each counter pressure of the series of counter pressures is different from one another, applied at the set location, and between zero and a diastolic pressure of the subject;
a sensor configured to measure, for each counter pressure of the series of counter pressures, a corresponding value of a first parameter related to pulse wave velocity when the respective counter pressure is applied; and
a processor coupled to the pressure device and the sensor, the processor configured with processor-executable instruction to perform operations comprising:
determining, after the sensor measures the value of the first parameter corresponding to at least one counter pressure of the series of counter pressures, whether a sufficient number of values have been collected;
in response to determining a sufficient number of values have not been collected, causing the sensor to measure the value of the first parameter corresponding to an additional counter pressure of the series of counter pressures;
for each model of a predetermined set of models that establishes a relationship of the first parameter measured to each counter pressure of the series of counter pressures, performing a fitting procedure to determine a fit of the respective model to the measured values of the first parameter, wherein performing the fitting procedure comprises weighting a higher counter pressure more heavily than a lower counter pressure among the series of counter pressures;
selecting a best-fit model from a predetermined set of models based on a result of the fitting procedure performed for each model of the predetermined set of models;
estimating a second parameter using the selected model; and
determining the estimated pulse wave velocity based on the second parameter estimated using the selected model.

15. The device of claim 14 , wherein the series of counter pressures each apply a pressure force perpendicular to a longitudinal direction of a limb containing the artery.

16. The device of claim 14 , wherein the pressure device includes a tightening band worn by the subject at the set location.

17. The device of claim 16 , wherein the sensor includes two sensors disposed between the tightening band and a portion of skin of the subject.

18. The device of claim 16 , wherein the sensor includes two sensors disposed on a portion of skin of the subject and outside opposed ends of the tightening band.

19. The device of claim 16 , wherein the sensor includes an ultrasound sensor embedded inside the tightening band.

20. The device of claim 14 , wherein the sensor is configured to measure the first parameter across a span of l

Assignees

• Philips Healthcare Informatics Inc
• Koninklijke Philips Nv

Inventors

• Lading Lars
• Baek David Boettcher

Classifications

• A61B5/055

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• A61B8/02

  Measuring pulse or heart rate · CPC title

• A61B5/7275

  Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor · CPC title

• A61B5/0285 Primary

  Measuring or recording phase velocity of blood waves · CPC title

• A61B5/0245

  by using sensing means generating electric signals, {i.e. ECG signals} · CPC title