Ultra miniature pressure sensor

• US 8,419,647 B2
• Filed: 06/27/2011
• 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 D., Obara, Robert Z., Ortiz, John E.
• Primary Examiner(s): Kahelin, Michael
• Assistant Examiner(s): TOTH, KAREN E
• Application Number:
  US13/169,174
• Publication Number:
  US 20110251497A1
• Time in Patent Office: 659 Days
• Field of Search: 600481-528
• US Class Current: 600/485
• 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 method, comprising:

providing a pressure-sensing guidewire that includes;

an elongate tubular member having an outer diameter of 0.018″

or less, the elongate tubular member having a proximal portion and an opposing distal portion;

a core wire extending within the elongate member from the proximal portion to the distal portion;

a flexible element coupled to the distal portion of the elongate tubular member, the flexible element having an outer diameter of 0.018″

or less and an increased flexibility compared to the elongate tubular member;

a sensor housing coupled to the flexible element, the sensor housing having an outer diameter of 0.018″

or less and a length between 1 mm and 5 mm, the sensor housing having an external wall, a lumen, and an opening extending through a portion of the external wall to the lumen;

a pressure sensor assembly disposed within the sensor housing and in fluid communication with the opening of the sensor housing;

a first electrical conductor electrically coupled to the pressure sensor assembly, the first electrical conductor extending from the pressure sensor assembly to the proximal portion of the elongate member;

a second electrical conductor electrically coupled to the pressure sensor assembly, the second electrical conductor extending from the pressure sensor assembly to the proximal portion of the elongate member;

a third electrical conductor electrically coupled to the pressure sensor assembly, the third electrical conductor extending from the pressure sensor assembly to the proximal portion of the elongate member; and

a flexible structure coupled to and extending distally from the sensor housing, the flexible structure including a radiopaque material and having an outer diameter of 0.018″

or less;

inserting at least a distal portion of the pressure-sensing guidewire into a vessel having a stenosis;

obtaining a first pressure measurement within the vessel with the pressure sensor assembly positioned proximal of the stenosis; and

obtaining a second pressure measurement within the vessel with the pressure sensor assembly positioned distal of the stenosis.

2. The method of claim 1, wherein the flexible element of the provided pressure-sensing guidewire has a length of approximately 27 cm.

3. The method of claim 2, wherein the flexible structure of the provided pressure-sensing guidewire has a length of approximately 3 cm.

4. The method of claim 3, wherein the flexible structure of the provided pressure-sensing guidewire is a coil.

5. The method of claim 4, wherein the coil of the provided pressure-sensing guidewire is formed of a metal.

6. The method of claim 5, wherein the coil of the provided pressure-sensing guidewire is formed of a material selected from the group of metals consisting of stainless steel, palladium, and tungsten platinum alloy.

7. The method of claim 1, wherein each of the elongate member, the flexible element, the sensor housing, and the flexible structure has an outer diameter of approximately 0.014″

.

8. The method of claim 1, wherein the sensor housing of the provided pressure-sensing guidewire is approximately 2 mm.

9. The method of claim 1, wherein the pressure sensor assembly of the provided pressure-sensing guidewire is mounted within the sensor housing such that an outer surface of the pressure sensor assembly is flush with an outer surface of the sensor housing.

10. The method of claim 1, wherein the pressure sensor assembly of the provided pressure-sensing guidewire is mounted within the sensor housing such that there is a distance between the opening and a diaphragm of the pressure sensor assembly.

11. The method of claim 1, wherein the pressure sensor assembly of the provided pressure-sensing guidewire is secured to the sensor housing by an adhesive.

12. The method of claim 11, wherein the adhesive securing the pressure sensor assembly to the sensor housing is an epoxy.

13. The method of claim 1, wherein a distal section of the core wire of the provided pressure-sensing guidewire is tapered.

14. The method of claim 13, wherein the tapered distal section of the core wire tapers from a larger diameter to a smaller diameter as the core wire extends distally.

15. The method of claim 1, wherein the pressure sensor assembly of the provided pressure-sensing guidewire has a width that is less than a width of the lumen of the sensor housing.

16. The method of claim 1, wherein the sensor housing of the provided pressure-sensing guidewire has a wall thickness between 0.001″

and 0.002″

.

17. The method of claim 1, further comprising comparing the first pressure measurement from the pressure-sensing guidewire to a pressure measurement from a guiding catheter.

18. The method of claim 17, further comprising equalizing the obtained pressure measurement from the pressure-sensing guidewire to the pressure measurement from the guiding catheter.

19. The method of claim 17, further comprising inserting at least the distal portion of the pressure-sensing guidewire through the guiding catheter.

20. The method of claim 17, wherein the obtained pressure measurement from the pressure-sensing guidewire is obtained with the pressure sensor assembly of the pressure-sensing guidewire positioned distal of a stenosis of the vessel.

21. The method of claim 17, further comprising performing an angioplasty procedure.

22. The method of claim 21, wherein performing the angioplasty procedure includes advancing an angioplasty catheter over the pressure-sensing guidewire.

23. The method of claim 22, wherein performing the angioplasty procedure further includes inflating a balloon of the angioplasty catheter to dilate the stenosis of the vessel.

24. The method of claim 1, further comprising comparing the second pressure measurement from the pressure-sensing guidewire to a pressure measurement from a guiding catheter.

25. The method of claim 1, wherein the provided pressure-sensing guidewire further comprises a Doppler transducer.

26. The method of claim 25, further comprising making a Doppler velocity measurement within the vessel with the Doppler transducer.

27. A method of evaluating a vessel of a patient with a pressure-sensing guidewire, comprising:

providing a pressure-sensing guidewire that includes;

an elongate tubular member having an outer diameter of 0.018″

or less, the elongate tubular member having a proximal portion and an opposing distal portion;

a core wire extending within the elongate member from the proximal portion to the distal portion;

a flexible element coupled to the distal portion of the elongate tubular member, the flexible element having an outer diameter of 0.018″

or less and an increased flexibility compared to the elongate tubular member;

a sensor housing coupled to the flexible element, the sensor housing having an outer diameter of 0.018″

or less and a length between 1 mm and 5 mm, the sensor housing having an external wall, a lumen, and an opening extending through a portion of the external wall to the lumen;

a pressure sensor assembly disposed within the sensor housing and in fluid communication with the opening of the sensor housing;

a first electrical conductor electrically coupled to the pressure sensor assembly, the first electrical conductor extending from the pressure sensor assembly to the proximal portion of the elongate member;

a second electrical conductor electrically coupled to the pressure sensor assembly, the second electrical conductor extending from the pressure sensor assembly to the proximal portion of the elongate member;

a third electrical conductor electrically coupled to the pressure sensor assembly, the third electrical conductor extending from the pressure sensor assembly to the proximal portion of the elongate member; and

a flexible structure coupled to and extending distally from the sensor housing, the flexible structure including a radiopaque material and having an outer diameter of 0.018″

or less; and

obtaining a pressure measurement from within the vessel with the pressure sensor assembly of the pressure-sensing guidewire.

28. The method of claim 27, wherein the flexible element of the provided pressure-sensing guidewire has a length of approximately 27 cm.

29. The method of claim 28, wherein the flexible structure of the provided pressure-sensing guidewire has a length of approximately 3 cm.

30. The method of claim 29, wherein the flexible structure of the provided pressure-sensing guidewire is a coil.

31. The method of claim 30, wherein the coil of the provided pressure-sensing guidewire is formed of a metal.

32. The method of claim 31, wherein the coil of the provided pressure-sensing guidewire is formed of a material selected from the group of metals consisting of stainless steel, palladium, and tungsten platinum alloy.

33. The method of claim 27, wherein each of the elongate member, the flexible element, the sensor housing, and the flexible structure has an outer diameter of approximately 0.014″

.

34. The method of claim 27, wherein the sensor housing of the provided pressure-sensing guidewire is approximately 2 mm.

35. The method of claim 27, wherein the pressure sensor assembly of the provided pressure-sensing guidewire is mounted within the sensor housing such that an outer surface of the pressure sensor assembly is flush with an outer surface of the sensor housing.

36. The method of claim 27, wherein the pressure sensor assembly of the provided pressure-sensing guidewire is mounted within the sensor housing such that there is a distance between the opening and a diaphragm of the pressure sensor assembly.

37. The method of claim 27, wherein the pressure sensor assembly of the provided pressure-sensing guidewire is secured to the sensor housing by an adhesive.

38. The method of claim 37, wherein the adhesive securing the pressure sensor assembly to the sensor housing is an epoxy.

39. The method of claim 27, wherein a distal section of the core wire of the provided pressure-sensing guidewire is tapered.

40. The method of claim 39, wherein the tapered distal section of the core wire tapers from a larger diameter to a smaller diameter as the core wire extends distally.

41. The method of claim 27, wherein the pressure sensor assembly of the provided pressure-sensing guidewire has a width that is less than a width of the lumen of the sensor housing.

42. The method of claim 27, wherein the sensor housing of the provided pressure-sensing guidewire has a wall thickness between 0.001″

and 0.002″

.

43. The method of claim 27, wherein the pressure measurement is obtained with the pressure sensor assembly of the pressure-sensing guidewire positioned distal of a stenosis of the vessel.

44. The method of claim 27, wherein the pressure measurement is obtained with the pressure sensor assembly of the pressure-sensing guidewire positioned proximal of a stenosis of the vessel.

45. The method of claim 27, further comprising comparing the obtained pressure measurement from the pressure-sensing guidewire to a pressure measurement from a guiding catheter.

46. The method of claim 45, further comprising equalizing the obtained pressure measurement from the pressure-sensing guidewire to the pressure measurement from the guiding catheter.

47. The method of claim 45, further comprising inserting at least the distal portion of the pressure-sensing guidewire through the guiding catheter.

48. The method of claim 45, wherein the obtained pressure measurement from the pressure-sensing guidewire is obtained with the pressure sensor assembly of the pressure-sensing guidewire positioned distal of a stenosis of the vessel.

49. The method of claim 45, wherein the obtained pressure measurement from the pressure-sensing guidewire is obtained with the pressure sensor assembly of the pressure-sensing guidewire positioned proximal of a stenosis of the vessel.

50. The method of claim 45, further comprising performing an angioplasty procedure.

51. The method of claim 50, wherein performing the angioplasty procedure includes advancing an angioplasty catheter over the pressure-sensing guidewire.

52. The method of claim 51, wherein performing the angioplasty procedure further includes inflating a balloon of the angioplasty catheter to dilate the stenosis of the vessel.

53. The method of claim 27, wherein the provided pressure-sensing guidewire further comprises a Doppler transducer.

54. The method of claim 53, further comprising making a Doppler velocity measurement within the vessel with the Doppler transducer.