Method for Determining Pulse Wave Velocity in an Artery

• US 20150238095A1
• Filed: 02/18/2015
• Published: 08/27/2015
• Est. Priority Date: 02/24/2014
• Status: Active Grant

• Current Assignee: Philips Healthcare Informatics Incorporated (Koninklijke Philips N.V.)
• Original Assignee: Qualcomm, Inc.
• Inventors: Lading, Lars, Baek, David Boettcher
• Granted Patent: US 10,959,622 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02422 within occluders
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate

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.

Claims

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 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;

measuring a first parameter related to pulse wave velocity when each of the series of counter pressures is applied;

estimating a second parameter in a model establishing a relationship of the first parameter measured to each of the series of counter pressures; and

determining the estimated pulse wave velocity based on the second parameter estimated in the 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 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 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 parameter includes using an ultrasound sensor embedded inside the tightening band.

7. The method of claim 1, wherein measuring 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 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 the first parameter includes detecting a distension of the artery over time.

10. The method of claim 1, wherein measuring the first parameter includes measuring a first set of parameters.

11. The method of claim 1, wherein 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 in the model includes a second set of parameters.

13. The method of claim 1, further comprising:

selecting the model from a predetermined set of models based on a best-fit of the model to the first parameter measured at each of the series of counter pressures.

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

15. The method of claim 1, wherein among the series of counter pressures, a higher counter pressure is weighted more heavily than a lower counter pressure when estimating the second parameter.

16. 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 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 a first parameter related to pulse wave velocity when each of the series of counter pressures is applied; and

a processor coupled to the pressure device and the sensor, the processor configured with processor-executable instruction to perform operations comprising;

estimating a second parameter in a model establishing a relationship of the first parameter measured to each of the series of counter pressures; and

determining the estimated pulse wave velocity based on the second parameter estimated in the model.

17. The device of claim 16, wherein the series of counter pressures each apply a pressure force perpendicular to a longitudinal direction of a limb containing the artery.

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

19. The device of claim 18, wherein the sensor includes two sensors disposed between the tightening band and a portion of skin of the subject.

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

21. The device of claim 18, wherein the sensor includes an ultrasound sensor embedded inside the tightening band.

22. The device of claim 16, wherein the sensor is configured to measure the first parameter across a span of less than 20 cm at the set location, wherein the series of counter pressures are each applied along the span.

23. The device of claim 16, wherein the sensor includes two sensors separated by a span along the artery to measure a transit time of a pulse between the two sensors.

24. The device of claim 16, wherein the sensor is configured to detect a distension of the artery over time.

25. The device of claim 16, wherein the sensor is configured to measure a first set of parameters.

26. The device of claim 16, wherein the sensor includes 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.

27. The device of claim 16, wherein the processor is configured such that the second parameter includes a second set of parameters.

28. The device of claim 16, wherein the processor is configured with processor-executable instructions to perform operations further comprising:

selecting the model from a predetermined set of models based on a best-fit of the model to the first parameter measured at each of the series of counter pressures.

29. The device of claim 16, wherein the processor is configured with processor-executable instructions to perform operations such that the model is selected from the group consisting of a predetermined stress-strain relationship of the artery, a Bramwell-Hill equation, an exponential model, and a bi-linear model.

30. The device of claim 16, wherein the processor is configured with processor-executable instructions to perform operations such that among the series of counter pressures, a higher counter pressure is weighted more heavily than a lower counter pressure when estimating the second parameter.

31. A device for determining an estimated pulse wave velocity of an artery of a subject, comprising:

means for applying a series of counter pressures at a set location on the subject over the artery with a pressure device, wherein each 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;

means for measuring a first parameter related to pulse wave velocity when each of the series of counter pressures is applied;

means for estimating a second parameter in a model establishing a relationship of the first parameter measured to each of the series of counter pressures; and

means for determining the estimated pulse wave velocity based on the second parameter estimated in the model.

32. The device of claim 31, wherein means for applying the series of counter pressures comprises means for applying each counter pressure so that a pressure force is applied perpendicular to a longitudinal direction of a limb containing the artery.

33. The device of claim 31, wherein means for applying the series of counter pressures include means for tightening a tightening band worn by the subject at the set location.

34. The device of claim 33, wherein means for measuring the first parameter includes means for measuring elements of the first parameter disposed between the tightening band and a portion of skin of the subject.

35. The device of claim 33, wherein means for measuring the first parameter includes means for measuring elements of the first parameter disposed on a portion of skin of the subject and outside opposed ends of the tightening band.

36. The device of claim 33, wherein means for measuring the first parameter includes means for measuring ultrasound embedded inside the tightening band.

37. The device of claim 31, wherein means for measuring the first parameter comprises means for measuring the first parameter across a span of less than 20 cm at the set location, wherein with each of the series of counter pressures applied along the span.

38. The device of claim 31, wherein means for measuring the first parameter includes means for measuring elements of the first parameter separated by a span along the artery to measure a transit time of a pulse through the span.

39. The device of claim 31, wherein means for measuring the first parameter includes means for detecting a distension of the artery over time.

40. The device of claim 31, wherein means for measuring the first parameter includes means for measuring a first set of parameters.

41. The device of claim 31, wherein means for measuring the first parameter includes 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.

42. The device of claim 31, wherein means for estimating the second parameter includes means for estimating a second set of parameters.

43. The device of claim 31, further comprising:

means for selecting the model from a predetermined set of models based on a best-fit of the model to the first parameter measured at each of the series of counter pressures.

44. The device of claim 31, wherein the model is selected from the group consisting of a predetermined stress-strain relationship of the artery, a Bramwell-Hill equation, an exponential model, and a bi-linear model.

45. The device of claim 31, wherein means for estimating the second parameter in the model establishing the relationship of the first parameter measured to each of the series of counter pressures comprises means for estimating the second parameter by weighting more heavily a higher counter pressure than a lower counter pressure among the series of counter pressures.

46. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor to perform operations for determining an estimated pulse wave velocity of an artery of a subject, the operations comprising:

applying a series of counter pressures at a set location on the subject over the artery with a pressure device, wherein each 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;

measuring a first parameter related to pulse wave velocity when each of the series of counter pressures is applied;

estimating a second parameter in a model establishing a relationship of the first parameter measured to each of the series of counter pressures; and

determining the estimated pulse wave velocity based on the second parameter estimated in the model.

47. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that the series of counter pressures each apply a pressure force perpendicular to a longitudinal direction of a limb containing the artery.

48. The non-transitory processor-readable storage medium of claim 46, wherein the series of counter pressures are each applied by a tightening band worn by the subject at the set location.

49. The non-transitory processor-readable storage medium of claim 48, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring the first parameter includes using two sensors disposed between the tightening band and a portion of skin of the subject.

50. The non-transitory processor-readable storage medium of claim 48, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring the first parameter includes using two sensors disposed on a portion of skin of the subject and outside opposed ends of the tightening band.

51. The non-transitory processor-readable storage medium of claim 48, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring the first parameter includes using an ultrasound sensor embedded inside the tightening band.

52. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring 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.

53. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring 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.

54. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring the first parameter includes detecting a distension of the artery over time.

55. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that measuring the first parameter includes measuring a first set of parameters.

56. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that 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.

57. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that the second parameter estimated in the model includes a second set of parameters.

58. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations further comprising:

selecting the model from a predetermined set of models based on a best-fit of the model to the first parameter measured at each of the series of counter pressures.

59. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that the model is selected from the group consisting of a predetermined stress-strain relationship of the artery, a Bramwell-Hill equation, an exponential model, and a bi-linear model.

60. The non-transitory processor-readable storage medium of claim 46, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that among the series of counter pressures, a higher counter pressure is weighted more heavily than a lower counter pressure when estimating the second parameter.