Apparatus and method of assessing a narrowing in a fluid fileld tube

Patent metadata

Field	Value
Publication number	US-12383147-B2
Application number	US-202217867155-A
Country	US
Kind code	B2
Filing date	Jul 18, 2022
Priority date	Jan 6, 2011
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

An apparatus and method of assessing a narrowing in a fluid filled tube having a fluid flow pressure wave having a backward-originating pressure component and a forward-originating pressure component without taking a flow velocity measurement, comprising: taking pressure measurements in the tube; separating the pressure components into the backward-originating pressure component and the forward-originating pressure component; identifying a time window when the differential of flow velocity (dU) is minimal or absent; and deriving the backward and forward pressure components for pressure measurements taken in at least the time window.

First claim

The invention claimed is:

1. A system of assessing a narrowing in a blood vessel, the system comprising:
at least one pressure-sensing probe sized and shaped for positioning within the blood vessel; and
a processor in communication with the at least one pressure-sensing probe, the processor configured to:
receive pressure measurements occurring during a cardiac cycle without hyperaemia obtained by the at least one pressure-sensing probe positioned within the blood vessel; and
calculate a pressure ratio using a subset of the pressure measurements occurring during a wave free period of the cardiac cycle, wherein the pressure ratio provides an assessment of a severity of the narrowing in the blood vessel.

2. The system of claim 1 , wherein a start of the wave free period occurs after a first characteristic of a pressure waveform of the received pressure measurements.

3. The system of claim 2 , wherein the first characteristic of the pressure waveform is a peak pressure.

4. The system of claim 2 , wherein an end of the wave free period occurs before a second characteristic of the pressure waveform of the received pressure measurements.

5. The system of claim 4 , wherein the second characteristic is an end of the pressure waveform.

6. The system of claim 1 , wherein the wave free period includes a time window between a peak pressure time (t Pmax ) and an end of pressure waveform time (t Pend ).

7. The system of claim 6 , wherein the time window extends from t Pmax +150 ms to t Pend −50 ms.

8. The system of claim 6 , wherein the time window is a mid-window between t Pmax and t Pend .

9. The system of claim 8 , wherein the time window is a mid 3/5 window between t Pmax and t Pend .

10. The system of claim 1 , wherein the wave free period has a length of at least 100 ms.

11. The system of claim 1 , wherein the wave free period has a predetermined duration.

12. The system of claim 1 , wherein the wave free period corresponds to when a differential of flow velocity (dU) is minimal or absent.

13. The system of claim 1 , wherein the wave free period corresponds to when a differential of flow velocity (dU) is below a threshold.

14. The system of claim 13 , wherein the threshold of the differential of flow velocity (dU) is a predetermined deviation from zero.

15. The system of claim 14 , wherein the predetermined deviation is ±2×10 −4 .

16. The system of claim 13 , wherein the threshold of the differential of flow velocity (dU) is a percentage of a maximum differential of flow velocity (dU max ).

17. The system of claim 13 , wherein the threshold is 20% or less than a maximum differential of flow velocity (dU max ).

18. The system of claim 1 , wherein the at least one pressure-sensing probe comprises a pressure-sensing wire.

19. The system of claim 1 , wherein the at least one pressure-sensing probe comprises a pressure transducer.

20. The system of claim 1 , wherein the processor is in wired communication with the at least one pressure-sensing probe.

21. The system of claim 1 , wherein the processor is in wireless communication with the at least one pressure-sensing probe.

22. The system of claim 1 , wherein the processor is further configured to:
identify the wave free period based on the received pressure measurements.

23. A method of assessing a narrowing in a blood vessel, the method comprising:
receiving, with a processor in communication with at least one pressure-sensing probe, pressure measurements occurring during a cardiac cycle without hyperaemia obtained by the at least one pressure-sensing probe while the at least one pressure-sensing probe is positioned within the blood vessel; and
calculating, with the processor, a pressure ratio using a subset of the pressure measurements occurring during a wave free period of the cardiac cycle, wherein the pressure ratio provides an assessment of a severity of the narrowing in the blood vessel.

24. The method of claim 23 , wherein a start of the wave free period occurs after a first characteristic of a pressure waveform of the received pressure measurements.

25. The method of claim 24 , wherein the first characteristic of the pressure waveform is a peak pressure.

26. The method of claim 24 , wherein an end of the wave free period occurs before a second characteristic of the pressure waveform of the received pressure measurements.

27. The method of claim 26 , wherein the second characteristic is an end of the pressure waveform.

28. The method of claim 23 , wherein the wave free period includes a time window between a peak pressure time (t Pmax ) and an end of pressure waveform time (t Pend ).

29. The method of claim 28 , wherein the time window extends from t Pmax +150 ms to t Pend −50 ms.

30. The method of claim 28 , wherein the time window is a mid-window between t Pmax and t Pend .

31. The method of claim 30 , wherein the time window is a mid 3/5 window between t Pmax and t Pend .

32. The method of claim 23 , wherein the wave free period has a length of at least 100 ms.

33. The method of claim 23 , wherein the wave free period has a predetermined duration.

34. The method of claim 23 , wherein the wave free period corresponds to when a differential of flow velocity (dU) is minimal or absent.

35. The method of claim 23 , wherein the wave free period corresponds to when a differential of flow velocity (dU) is below a threshold.

36. The method of claim 35 , wherein the threshold of the differential of flow velocity (dU) is a predetermined deviation from zero.

37. The method of claim 36 , wherein the predetermined deviation is ±2×10 −4 .

38. The method of claim 35 , wherein the threshold of the differential of flow velocity (dU) is a percentage of a maximum differential of flow velocity (dU max ).

39. The method of claim 35 , wherein the threshold is 20% or less than a maximum differential of flow velocity (dU max ).

40. The method of claim 23 , wherein the at least one pressure-sensing probe comprises a pressure-sensing wire.

41. The method of claim 23 , wherein the at least one pressure-sensing probe comprises a pressure transducer.

42. The method of claim 23 , wherein the processor is in wired communication with the at least one pressure-sensing probe.

43. The method of claim 23 , wherein the processor is in wireless communication with the at least one pressure-sensing probe.

44. The method of claim 23 , further comprising:
identifying, with the processor, the wave free period based on the received pressure measurements.

Assignees

• Medsolve Ltd
• Imperial College Sci Tech & Medicine
• Medsolve Pte Ltd
• Imperial College Of Science Tech & Medicine

Inventors

• Davies Helen
• Davies Justin

Classifications

• A61B5/7278

  Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals · CPC title

• A61B5/7264

  Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems · CPC title

• A61B5/0285

  Measuring or recording phase velocity of blood waves · CPC title

• A61B5/02125

  of pulse wave propagation time · CPC title

• A61B5/103

  Measuring devices for testing the shape, pattern, {colour,} size or movement of the body or parts thereof, for diagnostic purposes (measuring instruments specially adapted for dentistry A61C19/04) · CPC title