Ultra miniature pressure sensor

• US 8,419,648 B2
• Filed: 12/15/2005
• Issued: 04/16/2013
• Est. Priority Date: 09/02/1994
• Status: Expired due to Fees

• Current Assignee: Volcano Corporation (Koninklijke Philips N.V.)
• Original Assignee: Volcano Corporation (Koninklijke Philips N.V.)
• Inventors: Corl, Paul, Obara, Robert, Ortiz, John
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US11/303,249
• Publication Number:
  US 20060094982A1
• Time in Patent Office: 2,679 Days
• Field of Search: 600/300, 600/481, 600485-489, 600/500
• US Class Current: 600/486
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61M 2025/0002 with a pressure sensor at the distal end
• CPC Class Codes: A61M 2025/09008 having a balloon
• CPC Class Codes: A61M 2025/09083 having a coil around a core
• CPC Class Codes: A61M 25/09 Guide wires
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: G01L 19/0084 to the outside of the housing other details about the housing see G01L19/14
• CPC Class Codes: G01L 19/141 Monolithic housings, e.g. molded or one-piece housings
• CPC Class Codes: G01L 19/147 Details about the mounting of the sensor to support or covering means
• CPC Class Codes: G01L 19/149 of immersion sensor, e.g. where the sensor is immersed in the measuring medium or for in vivo measurements, e.g. by using catheter tips
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm

Abstract

A method of measuring blood pressure and velocity proximally and distally of a stenosis in a vessel carrying blood includes the steps of providing a guide wire having both a pressure sensor and a velocity sensor disposed on a distal region of the guide wire, introducing the guide wire into the vessel, advancing the guide wire to position the pressure sensor and the velocity sensor proximally and distally of the stenosis, and measuring the blood pressure and velocity proximally and distally of the stenosis with the pressure sensor and the velocity sensor.

Claims

1. A pressure sensor apparatus, comprising:

a long proximal hypotube having an outside diameter of 0.018″

or less,

a flexible floppy tip extending distal of the long proximal hypotube, the flexible floppy tip comprising;

a first flexible element, disposed near a distal portion of the long proximal hypotube, with an outer diameter of 0.018″

or less and an increased flexibility relative to the long proximal hypotube;

a short hypotube sensor housing disposed near a distal extremity of the first flexible element, the sensor housing having;

a cylindrical external wall having an outer diameter of 0.018″

or less,

a length between 1 mm and 5 mm,

a lumen, and

a cutout in the cylindrical external wall;

a second flexible element, disposed near a distal extremity of the short hypotube sensor housing, with an outer diameter of 0.018″

or less and an increased flexibility relative to the long proximal hypotube; and

a solid state pressure sensor mounted within the short hypotube sensor housing, such that;

a pressure sensitive region located at or near one end of the solid state pressure sensor projects into the lumen of the short hypotube sensor housing without contacting the cylindrical external wall of the sensor housing; and

the pressure sensitive region is exposed to ambient by the cutout in the cylindrical external wall of the sensor housing,

wherein the pressure sensitive region includes a diaphragm structure, a base plate, and at least one resistive element responsive to changes in pressure; and

three electrical conductors extending from a proximal portion of the long proximal hypotube to the solid state pressure sensor, the three electrical conductors coupled to the solid state pressure sensor such that the coupled portions of the three electrical conductors and the solid state pressure sensor are positioned within the short hypotube sensor housing.

2. The pressure sensor apparatus of claim 1, wherein the at least one resistive element consists of two resistive elements.

3. The pressure sensor apparatus of claim 2, wherein at least one of the two resistive elements is disposed on the solid state pressure sensor in the pressure sensitive region.

4. The pressure sensor apparatus of claim 1, wherein the solid state pressure sensor comprises a semiconductor material.

5. The pressure sensor apparatus of claim 1, wherein at least one resistive element overlies at least a portion of the diaphragm.

6. The pressure sensor apparatus of claim 1, comprising an end cap disposed distally from the second flexible element.

7. The pressure sensor apparatus of claim 6, wherein the end cap is rounded.

8. The pressure sensor apparatus of claim 7, wherein the end cap is hemi-spherical.

9. The pressure sensor apparatus of claim 1, wherein the three electrical conductors comprise a trifilar structure.

10. The pressure sensor apparatus of claim 1, comprising a core wire extending from a proximal extremity of the long proximal hypotube, through the sensor housing, and to a distal extremity of the second flexible element.

11. The pressure sensor apparatus of claim 1, wherein the second flexible element is a coil and comprises a radiopaque material.

12. The pressure sensor apparatus of claim 1, wherein the at least one resistive element comprises a first resistive element that responds positively to a pressure change and a second resistive element that responds negatively to the pressure change and the first and second resistive elements form a half bridge.

13. The pressure sensor apparatus of claim 1, wherein the base plate has a rectangular profile.

14. The pressure sensor apparatus of claim 1, wherein the diaphragm is positioned directly opposite the cutout in the sensor housing within the lumen of the sensor housing.

15. The pressure sensor apparatus of claim 1, wherein the first flexible element comprises a flexible elongate tubular member formed of a plastic material.

16. The pressure sensor apparatus of claim 1, wherein the first flexible element is a hypotube formed of a plastic material.

17. The pressure sensor apparatus of claim 1, wherein the first flexible element is a coil.

18. The pressure sensor apparatus of claim 1, wherein the first flexible element comprises a balloon.

19. The pressure sensor apparatus of claim 1, further comprising a core wire extending along a length of the long proximal hypotube and within the first flexible element.

20. The pressure sensor apparatus of claim 19, wherein the core wire tapers within the first flexible element.

21. The pressure sensor apparatus of claim 20, wherein the core wire tapers from a larger diameter to a smaller diameter as the core wire extends distally within the first flexible element.

22. The pressure sensor apparatus of claim 21, wherein the first flexible element comprises a plastic material.

23. The pressure sensor apparatus of claim 19, wherein the first flexible element has a length of approximately 27 cm.

24. The pressure sensor apparatus of claim 23, wherein the second flexible element is a coil and has a length of approximately 3 cm.

25. The pressure sensor apparatus of claim 1, wherein the first flexible element comprises a plastic material.

26. The pressure sensor apparatus of claim 1, wherein the solid state pressure sensor is secured to the sensor housing by an adhesive.

27. The pressure sensor apparatus of claim 1, wherein one of the three electrical conductors provides a common lead to the solid state pressure sensor.

28. The pressure sensor apparatus of claim 27, wherein two of the three electrical conductors are return leads from the solid state pressure sensor.

29. The pressure sensor apparatus of claim 28, wherein the common conductor is coupled to a pair of resistive elements and the return conductors are each coupled to a single one of the pair of resistive elements.

30. A pressure sensor apparatus, comprising:

a long proximal hypotube having an outside diameter of 0.018″

or less,

a flexible floppy tip extending distal of the long proximal hypotube, the flexible floppy tip comprising;

a short hypotube sensor housing disposed distal of a distal extremity of the long proximal hypotube, the short hypotube pressure sensor housing having;

an outer diameter of 0.018″

or less;

a length between 1 mm and 5 mm, and

a cutout in a wall thereof;

a first flexible element, disposed between the long proximal hypotube and the short hypotube sensor housing, with an outer diameter of 0.018″

or less and an increased flexibility relative to the long proximal hypotube;

a second flexible element, disposed distal of the short hypotube sensor housing, with an outer diameter of 0.018″

or less and an increased flexibility relative to the long proximal hypotube;

a solid state pressure sensor comprising a pressure sensitive region located at or near one end thereof with a diaphragm and at least one resistive element responsive to pressure;

wherein the solid state pressure sensor is disposed within the short hypotube sensor housing such that;

the pressure sensitive region is spaced from an external wall of the short hypotube sensor housing; and

the diaphragm is exposed to ambient by the cutout in the short hypotube sensing housing; and

three electrical conductors extending from a proximal extremity of the long proximal hypotube to the solid state pressure sensor, a distal portion of the electrical conductors coupled to the solid state pressure sensor within the short hypotube sensor housing.

31. The pressure sensor apparatus of claim 30, wherein the second flexible element is a coil and comprises a radiopaque material.

32. The pressure sensor apparatus of claim 30, wherein the long proximal hypotube has an outside diameter of approximately 0.014″

or less.

33. The pressure sensor apparatus of claim 30, wherein the outer diameter of the sensor housing is equal to the outer diameter of the long proximal hypotube.

34. The pressure sensor apparatus of claim 30, further comprising a core wire extending along a length of the long proximal hypotube.

35. The pressure sensor apparatus of claim 30, wherein the first flexible element comprises a flexible elongate tubular member formed of a plastic material.

36. The pressure sensor apparatus of claim 30, wherein the first flexible element is a hypotube formed of a plastic material.

37. The pressure sensor apparatus of claim 30, wherein the first flexible element is a coil.

38. The pressure sensor apparatus of claim 30, wherein the first flexible element comprises a balloon.

39. The pressure sensor apparatus of claim 30, further comprising a core wire extending along a length of the guidewire and within the first flexible element.

40. The pressure sensor apparatus of claim 39, wherein the core wire tapers within the first flexible element.

41. The pressure sensor apparatus of claim 40, wherein the core wire tapers from a larger diameter to a smaller diameter as the core wire extends distally within the first flexible element.

42. The pressure sensor apparatus of claim 39, wherein the first flexible element has a length of approximately 27 cm.

43. The pressure sensor apparatus of claim 42, wherein the second flexible element is a coil and has a length of approximately 3 cm.

44. The pressure sensor apparatus of claim 43, wherein the sensor housing has a length between 1 mm and 5 mm.

45. The pressure sensor apparatus of claim 30, wherein the first flexible element comprises a plastic material.

46. The pressure sensor apparatus of claim 30, further comprising an end cap disposed distally from the second flexible element.

47. The pressure sensor apparatus of claim 46, wherein the end cap is rounded.

48. The pressure sensor apparatus of claim 47, wherein the end cap is hemi-spherical.

49. The pressure sensor apparatus of claim 30, wherein the solid state pressure sensor is secured to the sensor housing by an adhesive.

50. The pressure sensor apparatus of claim 30, wherein one of the three conductors provides a common conductor to the solid state pressure sensor.

51. The pressure sensor apparatus of claim 50, wherein two of the three conductors are return conductors from the solid state pressure sensor.

52. The pressure sensor apparatus of claim 51, wherein the common conductor is coupled to a pair of resistive elements and the return conductors are each coupled to a single one of the pair of resistive elements.

53. A pressure sensor apparatus comprising:

a long proximal hypotube having an outside diameter of 0.018″

or less,

a first flexible element, disposed distal of the long proximal hypotube, with an outer diameter of 0.018″

or less and an increased flexibility relative to the long proximal hypotube,

a short hypotube sensor housing disposed distal of a distal extremity of the first flexible element, and having a cylindrical wall with an outer diameter of 0.018″

or less, a length between 1 mm and 5 mm, and a cutout in the cylindrical wall;

a second flexible element, disposed distally from the short hypotube sensor housing, with an outer diameter of 0.018″

or less and an increased flexibility relative to the long proximal hypotube,

a solid state pressure sensor mounted within the short hypotube sensor housing such that a pressure sensitive region of the solid state pressure sensor is exposed to ambient via the cutout, the solid state pressure sensor comprising at least one resistive element responsive to pressure, and

electrical conductors extending from a proximal extremity of the long proximal hypotube to the solid state pressure sensor, wherein the electrical conductors are coupled to the solid state pressure sensor within the short hypotube sensor housing and wherein the electrical conductors are coupled to conducting sleeves at the proximal extremity of the long proximal hypotube.

54. The pressure sensor apparatus of claim 53, wherein the electrical conductors comprise three conductors.

55. The pressure sensor apparatus of claim 53, wherein the second flexible element is a coil and comprises a radiopaque material.

56. The pressure sensor apparatus of claim 53, wherein the at least one resistive element comprises a first resistive element that responds positively to a pressure change and a second resistive element that responds negatively to the pressure change and the first and second resistive elements form a half bridge.

57. The pressure sensor apparatus of claim 56, wherein at least one of the plurality of resistive elements is disposed on the solid state pressure sensor in the pressure sensitive region.

58. The pressure sensor apparatus of claim 53, wherein the first flexible element comprises a flexible elongate tubular member formed of a plastic material.

59. The pressure sensor apparatus of claim 53, wherein the first flexible element is a hypotube formed of a plastic material.

60. The pressure sensor apparatus of claim 53, wherein the first flexible element is a coil.

61. The pressure sensor apparatus of claim 53, wherein the first flexible element is a balloon.

62. The pressure sensor apparatus of claim 53, further comprising a core wire extending along a length of the long proximal hypotube and within the first flexible element.

63. The pressure sensor apparatus of claim 53, wherein the core wire tapers within the first flexible element.

64. The pressure sensor apparatus of claim 63, wherein the core wire tapers from a larger diameter to a smaller diameter as the core wire extends distally within the first flexible element.

65. The pressure sensor apparatus of claim 53, wherein the first flexible element has a length of approximately 27 cm.

66. The pressure sensor apparatus of claim 65, wherein the second flexible element is a coil and has a length of approximately 3 cm.

67. The pressure sensor apparatus of claim 66, wherein the sensor housing has a length between 1 mm and 5 mm.

68. The pressure sensor apparatus of claim 53, wherein the flexible element comprises a plastic material.

69. The pressure sensor apparatus of claim 53, further comprising an end cap disposed distally from the the second flexible element.

70. The pressure sensor apparatus of claim 69, wherein the end cap is rounded.

71. The pressure sensor apparatus of claim 70, wherein the end cap is hemi-spherical.

72. The pressure sensor apparatus of claim 53, wherein at least a portion of the solid state pressure sensor is secured to the sensor housing by an adhesive.

73. The pressure sensor apparatus of claim 53, wherein one of three electrical conductors provides a common lead to the solid state pressure sensor.

74. The pressure sensor apparatus of claim 73, wherein two of the three electrical conductors are return leads from the solid state pressure sensor.

75. The pressure sensor apparatus of claim 74, wherein the common lead is coupled to a pair of resistive elements and the return leads are each coupled to a single one of the pair of resistive elements.