Intra-Vascular Device With Pressure Detection Capabilities Using Pressure Sensitive Material

• US 20090125007A1
• Filed: 11/09/2007
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: Spectranetics Corporation (Koninklijke Philips N.V.)
• Original Assignee: Spectranetics Corporation (Koninklijke Philips N.V.)
• Inventors: Splinter, Robert
• Granted Patent: US 9,066,742 B2
• Time in Patent Office: Days
• US Class Current: 606/15
• CPC Class Codes: A61B 18/24 with a catheter A61B18/26, A61B18/28 take precedence
• CPC Class Codes: A61B 18/245 for removing obstructions in blood vessels or calculi
• CPC Class Codes: A61B 2018/00642 with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/00732 Frequency
• CPC Class Codes: A61B 2018/00904 Automatic detection of target tissue
• CPC Class Codes: A61B 2090/065 for measuring contact or contact pressure
• CPC Class Codes: A61B 2090/0813 Accessories designed for easy sterilising, i.e. re-usable
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: A61B 5/1079 using optical or photographic means
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence

Abstract

A laser catheter with a pressure sensor is provided according to embodiments of the invention. The pressure sensor may be coupled with the distal end of the laser catheter and may comprise any of various piezoelectric materials, for example Polyvinylidene Difluoride (PVDF). In various embodiments of the invention the pressure sensor is configured to detect pressure longitudinally and coaxially. The pressure sensor may provide an electric potential that is proportional to the vessel pressure and may be used to monitor and/or adjust laser parameters. In other embodiments the results from the pressure sensor may be used to determine the vessel size and/or the type of material being ablated.

Claims

1. A laser catheter having an outer surface, a distal end and proximal end, the laser catheter comprising:

a fiber optic including a distal end and a proximal end, wherein the fiber optic is coincident with the catheter substantially along the length of the catheter, the proximal end of the fiber optic is coincident with the proximal end of the catheter, the distal end of the fiber optic is coincident with the distal end of the catheter, the proximal end is configured to receive light from a laser, and the fiber optic directs light through the catheter toward the distal end of the fiber optic to; and

a pressure sensor coupled with the laser catheter near the distal end of the fiber optic.

2. The laser catheter according to claim 1, wherein the pressure sensor is configured to detect radial pressure, wherein the radial pressure is pressure detected on the outer surface of the catheter near the distal end of the fiber optic.

3. The laser catheter according to claim 1, wherein the pressure sensor is located within the lining of the lumen.

4. The laser catheter according to claim 1, wherein the fiber optic comprises a plurality of fibers and the pressure sensor comprises piezo material located between the plurality of fibers.

5. The laser catheter according to claim 4, wherein the pressure sensor is configured to detect radial pressure, wherein the radial pressure is pressure detected perpendicular to the length of the catheter.

6. The laser catheter according to claim 4, wherein the pressure sensor is configured to detect longitudinal pressure, wherein the longitudinal pressure is pressure detected along a longitudinal path extending from the distal end of the catheter.

7. The laser catheter according to claim 1, wherein the pressure sensor comprises a portion of the lumen core.

8. The laser catheter according to claim 1, wherein the pressure sensor is configured to detect longitudinal pressure, wherein the longitudinal pressure is pressure detected along a longitudinal path extending from the distal end of the catheter.

9. The laser catheter according to claim 1, further comprising a communication wire coupled with the pressure sensor and running the length of the fiber optic, wherein the communication wire is configured to communicate pressure information to a controller.

10. The laser catheter according to claim 1, further comprising a light source coupled with pressure sensor and at least one fiber optic, wherein the light source converts pressure signals from the pressure sensor into an optical signal that is transmitted through the fiber optic.

11. The laser catheter according to claim 1, wherein the pressure sensor comprises a piezoelectric pressure sensor.

12. The laser catheter according to claim 1, wherein the pressure sensor comprises Polyvinylidene Difluoride.

13. The laser catheter according to claim 1, wherein the pressure sensor comprises at least one layer of transducing film on the exterior outer diameter of the catheter.

14. The laser catheter according to claim 1, wherein the pressure sensor comprises:

a band with an inner and outer surface, wherein the band is configured to allow the distal end of the catheter to pass through the inner diameter of the band; and

a strain sensor coupled with the catheter near the distal end of the catheter and coupled with the band, wherein the strain sensor is configured to transduce motion of the band relative to the catheter into an electrical signal proportional to a pressure on the band.

15. The laser catheter according to claim 14, wherein the band comprises at least one of a conductive rigid coating and mechanically rigid coating.

16. The laser catheter according to claim 14, wherein the strain sensor comprises Polyvinylidene Difluoride.

17. The laser catheter according to claim 1, wherein the pressure sensor measures the amplitude of the pressure incident thereon.

18. The laser catheter according to claim 1, wherein the pressure sensor measures the frequency of the pressure incident thereon.

19. A method for monitoring laser atherectomy within a cavity using pressure measurements, the method comprising:

inserting a laser catheter within the cavity, wherein the laser catheter includes a fiber optic to channel laser light from a laser to a distal tip of the laser catheter and a pressure sensor coupled with the laser catheter near the distal tip of the laser catheter;

pulsing the laser using a first set of laser parameters;

measuring the pressure within the cavity using the pressure sensor;

determining whether the detected pressure within the cavity is within tolerances; and

changing the laser parameters to a second set of laser parameters in response to the determining whether the detected pressure within the cavity is within tolerances.

20. The method according to claim 19, wherein the pressure sensor measures at least one of the amplitude and the frequency of the pressure within the cavity.

21. The method according to claim 19, wherein the laser parameters include at least one of the repetition rate and the fluence.

22. The method according to claim 19, wherein the second set of laser parameters provide laser pulses with less power than the first set of laser parameters.

23. A laser catheter having an outer surface, a distal end and proximal end, the laser catheter comprising:

a lumen within the catheter that runs the longitudinal length of the catheter;

a fiber optic including a distal end and a proximal end, wherein the fiber optic is coincident with the catheter substantially along the length of the catheter, the proximal end of the fiber optic is coincident with the proximal end of the catheter, the distal end of the fiber optic is coincident with the distal end of the catheter, the proximal end is configured to receive light from a laser, and the fiber optic is configured to direct light through the catheter from the distal end of the fiber optic;

a band with an inner and outer surface, wherein the band is configured to allow the distal end of the catheter to pass through the inner diameter of the band; and

a strain sensor coupled with the catheter near the distal end of the catheter and coupled with the band, wherein the strain sensor is configured to transform motion of the band relative to the catheter into an electrical signal proportional to a pressure on the band, the strain sensor comprises Polyvinylidene Difluoride, and the strain sensor is configured to detect pressure along a longitudinal path extending from the distal end of the catheter.

24. A laser catheter having an outer surface, a distal end and proximal end, the laser catheter comprising:

a lumen within the catheter that runs the longitudinal length of the catheter;

a fiber optic including a distal end and a proximal end, wherein the fiber optic is coincident with the catheter substantially along the length of the catheter, the proximal end of the fiber optic is coincident with the proximal end of the catheter, the distal end of the fiber optic is coincident with the distal end of the catheter, the proximal end is configured to receive light from a laser, and the fiber optic is configured to direct light through the catheter from the distal end of the fiber optic;

a pressure sensor comprising at least one layer of Polyvinylidene Difluoride film on the outer diameter of the catheter, wherein the pressure sensor is configured to detect pressure detected on the outer surface of the catheter near the distal end of the fiber optic.

25. A method for identifying cavity size using a laser catheter within the cavity, the method comprising:

inserting the laser catheter within the cavity, wherein the laser catheter includes a fiber optic to channel laser light from a laser to a distal tip of the laser catheter and a pressure sensor coupled with the laser catheter near the distal tip of the laser catheter;

pulsing a laser coupled with the laser catheter using a first set of laser parameters; and

measuring the frequency response of the material within the cavity in response to the laser pulsing using a pressure sensor.

26. The method according to claim 25, further comprising determining the cavity size using the measured frequency response.

27. The method according to claim 25, further comprising identifying the tissue within the cavity based on at least the measured frequency response.