Apparatus and method for controlled removal of stenotic material from stents

• US 20020016624A1
• Filed: 02/14/2001
• Published: 02/07/2002
• Est. Priority Date: 02/12/1997
• Status: Abandoned Application

• Current Assignee: Prolifix Medical Incorporated
• Original Assignee: Prolifix Medical Incorporated
• Inventors: Leary, James J., Williams, Ronald G., Patterson, Greg R.
• Application Number:
  US09/784,625
• Publication Number:
  US 20020016624A1
• Time in Patent Office: Days
• US Class Current: 623/1.12
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 17/3207 Atherectomy devices working by cutting or abrading; Similar devices specially adapted for non-vascular obstructions A61B17/32037 takes precedence; endoscopic cutting instruments A61B17/320016
• CPC Class Codes: A61B 17/320725 with radially expandable cutting or abrading elements A61B17/32075 takes precedence
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00119 alarm; indicating an abnormal situation
• CPC Class Codes: A61B 2017/2212 having a closed distal end, e.g. a loop
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 2217/005 with suction drainage system
• CPC Class Codes: A61F 2/82 Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07; instruments specially adapted for placement or removal of stents or stent-grafts A61F2/95; for closing wounds, or holding wounds closed A61B17/04 - A61B17/115; dilators A61M29/00

Abstract

Apparatus and methods for treating in-stent restenosis are described for removing stenotic material from within previously stented regions of a patient'"'"'s vasculature. The apparatus includes a catheter system having a stenotic material removal mechanism mounted on a distal portion of an elongated inner catheter. A sensing means, such as one or more sensing electrodes, are positioned on an outer surface of the apparatus. In addition, the apparatus optionally includes control means for diametrically expanding the stenotic material removal mechanism for effective recanalization of the stent. A coaxial outer catheter is provided for aspirating stenotic material which is removed from within the stent. In addition, embolic filter apparatus are described for collecting the stenotic material removed from within the stent. The methods comprise operating the stenotic material removal mechanism within a body vessel, typically a coronary artery or other artery, which has become restenosed or otherwise occluded following the initial stent placement, and sensing the proximity or contact between the stenotic material removal mechanism and the stent within the arterial wall so that the stenosis can be effectively recanalized without damaging the stent. The sensing means may be used to indicate an unsafe condition that might lead to stent damage, in response to which, the stenotic material removal mechanism may be manually or automatically deactivated. Alternatively or additionally, the sensing means may be used to indicate an appropriate endpoint for the stenotic material removal process.

Claims

1. An apparatus for removing stenotic material from within a stent located within a body vessel, said apparatus comprising:

a stenotic material removal mechanism for removing stenotic material from within the stent,

sensor means associated with said stenotic material removal mechanism for sensing proximity or contact between said stenotic material removal mechanism and the stent,

whereby said sensor means is used to determine an unsafe condition or an appropriate endpoint for removal of stenotic material from within the stent based on the sensed proximity or contact between said stenotic material removal mechanism and the stent for effective recanalization of the body vessel.

2. The apparatus of claim 1 further comprising a control means for controlling a depth to which said stenotic material removal mechanism removes the stenotic material from within the stent.

3. The apparatus of claim 2 wherein said control means comprises a mechanism for diametrically expanding said stenotic material removal mechanism.

4. The apparatus of claim 1 further comprising a means for directing said stenotic material removal mechanism to remove stenotic material from a selected area within the stent.

5. The apparatus of claim 1 further comprising a means for diametrically expanding said stenotic material removal mechanism.

6. The apparatus of claim 1 wherein said stenotic material removal mechanism comprises at least one longitudinally oriented blade.

7. The apparatus of claim 1 wherein said stenotic material removal mechanism comprises a plurality of longitudinally oriented blades.

8. The apparatus of claim 7 wherein said longitudinally oriented blades are resiliently biased to expand radially outward from a central axis of said stenotic material removal mechanism.

9. The apparatus of claim 1 wherein said stenotic material removal mechanism comprises a plurality of helically configured blades.

10. The apparatus of claim 9 wherein said helically configured blades are resiliently biased to expand radially outward from a central axis of said stenotic material removal mechanism.

11. The apparatus of claim 1 wherein said stenotic material removal mechanism comprises a rotating blade.

12. The apparatus of claim 1 wherein said stenotic material removal mechanism comprises a rotating abrasive tool.

13. The apparatus of claim 1 wherein said stenotic material removal mechanism comprises a cage-like network of filaments.

14. The apparatus of claim 1 further comprising a monitoring means associated with said sensor means for monitoring the proximity or contact between said stenotic material removal mechanism and the stent.

15. The apparatus of claim 14 wherein said sensor means comprises at least one electrical conductor on an exterior of said apparatus and said monitoring means comprises a leakage current detector for detecting a leakage current when said at least one electrical conductor contacts said stent.

16. The apparatus of claim 14 wherein said sensor means comprises a first electrical conductor and a second electrical conductor on an exterior of said apparatus and said monitoring means comprises a leakage current detector for detecting a leakage current when said first electrical conductor and said second electrical conductor contacts said stent.

17. The apparatus of claim 14 wherein said sensor means comprises at least one electrical conductor within said apparatus and said monitoring means comprises a means for detecting a change in electrical impedance when said at least one electrical conductor approaches said stent.

18. The apparatus of claim 14 wherein said sensor means comprises a first electrical conductor and a second electrical conductor within said apparatus and said monitoring means comprises a means for detecting a change in electrical impedance when said first electrical conductor and said second electrical conductor approach said stent.

19. The apparatus of claim 14 wherein said monitoring means produces a signal indicative of the proximity or contact between said stenotic material removal mechanism and the stent.

20. The apparatus of claim 14 wherein said monitoring means includes means for deactivating said stenotic material removal mechanism when a predetermined level of proximity or contact between said stenotic material removal mechanism and the stent is detected.

21. The apparatus of claim 1 wherein said stenotic material removal mechanism is positioned at a distal portion of a first elongated catheter shaft.

22. The apparatus of claim 21 wherein said first elongated catheter shaft includes a lumen for passage of a guidewire therethrough.

23. The apparatus of claim 21 further comprising a second elongated catheter shaft positioned coaxially around said first elongated catheter shaft.

24. The apparatus of claim 23 wherein said second elongated catheter shaft includes an internal lumen for aspiration of stenotic material removed from within the stent.

25. The apparatus of claim 1 further comprising a stenotic material collection mechanism for collecting stenotic material removed from within the stent.

26. The apparatus of claim 25 wherein said stenotic material collection mechanism comprises an embolic filter positioned in operative association with said stenotic material removal mechanism.

27. The apparatus of claim 26 wherein said embolic filter is positioned coaxially with said stenotic material removal mechanism.

28. The apparatus of claim 25 wherein said stenotic material collection mechanism is positioned internally to said stenotic material removal mechanism.

30. The apparatus of claim 29 wherein said means deactivates said stenotic material removal mechanism when or before the stenotic material removal mechanism engages the stent.

31. The apparatus of claim 29 wherein said means includes a sensor for sensing contact between said stenotic material removal mechanism and the stent.

32. The apparatus of claim 29 wherein said means includes a sensor for sensing proximity between said stenotic material removal mechanism and the stent.

33. The apparatus of claim 29 wherein said means includes sensor means for sensing contact and proximity between said stenotic material removal mechanism and the stent.

34. The apparatus of claim 29 wherein said means includes a mechanism for diametrically expanding said stenotic material removal mechanism.

35. The apparatus of claim 29 further comprising a means for directing said stenotic material removal mechanism to remove stenotic material from a selected area within the stent.

36. The apparatus of claim 29 wherein said stenotic material removal mechanism comprises at least one longitudinally oriented blade.

37. The apparatus of claim 29 wherein said stenotic material removal mechanism comprises a plurality of longitudinally oriented blades.

38. The apparatus of claim 29 wherein said stenotic material removal mechanism comprises a plurality of helically configured blades.

39. The apparatus of claim 29 wherein said stenotic material removal mechanism comprises a rotating blade.

40. The apparatus of claim 29 wherein said stenotic material removal mechanism comprises a rotating abrasive tool.

41. The apparatus of claim 29 wherein said stenotic material removal mechanism comprises a cage-like network of filaments.

29. An apparatus for removing stenotic material from within a stent located within a body vessel, said apparatus comprising:

a catheter shaft having a proximal end and a distal end,

a stenotic material removal mechanism, and

means coupled to the stenotic material removal mechanism for increasing a depth to which the stenotic material removal mechanism removes the stenotic material from within the stent, wherein said means is limited to prevent further increase in depth when or before the stenotic material removal mechanism engages the stent.

42. An apparatus for removing stenotic material from within a body vessel, said apparatus comprising:

a stenotic material removal mechanism for removing stenotic material from within the body vessel, said stenotic material removal mechanism having a plurality of elongated blades, and

a stenotic material collection mechanism for collecting stenotic material removed from within the body vessel, said stenotic material collection mechanism including an expandable filter medium enclosed and supported by said plurality of elongated blades.

43. The apparatus of claim 42 further comprising a means for diametrically expanding said stenotic material removal mechanism.

44. The apparatus of claim 42 wherein said elongated blades are resiliently biased to expand radially outward from a central axis of said stenotic material removal mechanism.

46. The method of claim 45 further comprising controlling a depth to which said stenotic material removal mechanism removes the stenotic material from within the stent.

47. The method of claim 45 comprising diametrically expanding said stenotic material removal mechanism.

48. The method of claim 45 comprising directing said stenotic material removal mechanism to remove stenotic material from a selected area within the stent.

49. The method of claim 45 further comprising producing a signal indicative of the proximity or contact between said stenotic material removal mechanism and the stent.

50. The method of claim 45 further comprising deactivating said stenotic material removal mechanism when a predetermined level of proximity or contact between said stenotic material removal mechanism and the stent is detected.

51. The method of claim 45 further comprising monitoring the proximity or contact between said stenotic material removal mechanism and the stent.

52. The method of claim 51 wherein said sensor means comprises at least one electrical conductor on an exterior of said stenotic material removal mechanism and wherein the step of monitoring comprises detecting a leakage current when said at least one electrical conductor contacts the stent.

53. The method of claim 51 wherein said sensor means comprises a first electrical conductor and a second electrical conductor on an exterior of said stenotic material removal mechanism and wherein the step of monitoring comprises detecting a leakage current when said first electrical conductor and said second electrical conductor contacts the stent.

54. The method of claim 51 wherein said sensor means comprises at least one electrical conductor positioned on said stenotic material removal mechanism and wherein the step of monitoring comprises detecting a change in electrical impedance when said at least one electrical conductor approaches the stent.

55. The method of claim 51 wherein said sensor means comprises a first electrical conductor and a second electrical conductor positioned on said stenotic material removal mechanism and wherein the step of monitoring comprises detecting a change in electrical impedance when said first electrical conductor and said second electrical conductor approach the stent.

56. The method of claim 45 further comprising aspirating stenotic material removed from within the stent.

57. The method of claim 45 further comprising collecting stenotic material removed from within the stent.

58. The method of claim 45 further comprising inserting said stenotic material removal mechanism into the body vessel on an elongated catheter.

59. The method of claim 58 further comprising introducing said stenotic material removal mechanism on said elongated catheter into the body vessel through a percutaneous puncture.

45. A method for removing stenotic material from within a stent located within a body vessel, said method comprising:

operating a stenotic material removal mechanism to remove stenotic material from within the stent;

sensing proximity or contact between said stenotic material removal mechanism and the stent; and

determining an appropriate endpoint for removal of stenotic material from within the stent based on the sensed proximity or contact between said stenotic material removal mechanism and the stent for effective recanalization of the body vessel.

60. A method for removing stenotic material from within a stent located within a body vessel, said method comprising:

engaging a stenotic material removal mechanism to remove a portion of stenotic material from within the stent;

expanding the stenotic material removal mechanism to remove additional portions of the stenotic material; and

limiting the expansion of the stenotic material removal mechanism when or before the stenotic material removal mechanism engages the stent.

61. The method of claim 60 comprising diametrically expanding said stenotic material removal mechanism.

62. The method of claim 60 further comprising deactivating said stenotic material removal mechanism when or before the stenotic material removal mechanism engages the stent.

63. The method of claim 60 further comprising directing said stenotic material removal mechanism to remove stenotic material from a selected area within the stent.

64. The method of claim 60 further comprising sensing proximity or contact between said stenotic material removal mechanism and the stent.

65. The method of claim 64 further comprising deactivating said stenotic material removal mechanism when a predetermined level of proximity or contact between said stenotic material removal mechanism and the stent is detected.

66. The method of claim 60 further comprising aspirating stenotic material removed from within the stent.

67. The method of claim 60 further comprising collecting stenotic material removed from within the stent.

68. The method of claim 60 further comprising inserting said stenotic material removal mechanism into the body vessel on an elongated catheter.

69. The method of claim 68 further comprising introducing said stenotic material removal mechanism on said elongated catheter into the body vessel through a percutaneous puncture.

70. A catheter kit comprising:

(a) a catheter including;

a catheter shaft having a proximal end and a distal end,

a stenotic material removal mechanism, wherein said removal mechanism is expandable, and

(b) instructions for use setting forth the following steps;

percutaneously introducing the stenotic material removal mechanism into a restenosed stent in a blood vessel;

engaging the stenotic material removal mechanism to remove a portion of stenotic material from within the restenosed stent;

expanding the stenotic material removal mechanism to remove additional portions of the stenotic material; and

limiting the expansion of the stenotic material removal mechanism when or before the stenotic material removal mechanism engages the stent; and

(c) a package holding the catheter and the instructions for use.