Thermal treatment methods and apparatus with focused energy application

• US 20020065512A1
• Filed: 07/13/2001
• Published: 05/30/2002
• Est. Priority Date: 07/13/2000
• Status: Active Grant

• Current Assignee: Recor Medical, Inc. (Otsuka Holdings Company Limited)
• Original Assignee: Transurgical, Inc.
• Inventors: Fjield, Todd, Lopath, Patrick David, Harhen, Edward Paul, Acker, David E.
• Granted Patent: US 6,635,054 B2
• Time in Patent Office: Days
• US Class Current: 606/27
• CPC Class Codes: A61B 17/2202 the ultrasound transducer being inside patient's body at the distal end of the catheter
• CPC Class Codes: A61B 17/2251 characterised by coupling elements between the apparatus, e.g. shock wave apparatus or locating means, and the patient, e.g. details of bags, pressure control of bag on patient
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 18/24 with a catheter A61B18/26, A61B18/28 take precedence
• CPC Class Codes: A61B 2017/00274 Prostate operation, e.g. prostatectomy, turp, bhp treatment
• CPC Class Codes: A61B 2017/22024 with a part reflecting mechanical vibrations, e.g. for focusing
• CPC Class Codes: A61B 2017/22027 Features of transducers
• CPC Class Codes: A61B 2017/22068 Centering
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00547 Prostate
• CPC Class Codes: A61M 2025/1059 having different inflatable sections mainly depending on the response to the inflation pressure, e.g. due to different material properties with different compartments A61M2025/1072
• CPC Class Codes: A61N 7/022 intracavitary

Abstract

A collapsible ultrasonic reflector incorporates a gas-filled reflector balloon, a liquid-filled structural balloon an ultrasonic transducer disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal region to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Claims

1. Apparatus for applying energy within the body of a living subject comprising:

(a) a probe having a proximal end and a distal end adapted for insertion into the body of the patient;

(b) an ultrasonic emitter mounted to the probe assembly adjacent the distal end thereof;

(c) an expansible structure mounted on said probe adjacent the distal end thereof, said expansible structure having a collapsed condition and an expanded condition, said expansible structure including a reflector balloon having an interior space, said ultrasonic emitter being disposed outside of the interior space of the reflector balloon, said reflector balloon having an active region juxtaposed with the emitter when the expansible structure is in said expanded condition so that ultrasonic energy emitted by said emitter will impinge on the active region from outside of the reflector balloon;

whereby when said reflector balloon is inflated with a gas and a liquid is present outside of the reflector balloon, the gas within said reflector balloon and the liquid will form a reflective interface at the active region and ultrasonic energy emitted by said emitter will be reflected from said active region towards tissue of the subject adjacent the expansible structure.

2. Apparatus as claimed in claim 1, wherein said probe has a reflector balloon conduit communicating with the interior space of the reflector balloon, said reflector balloon conduit extending to a location adjacent the proximal end of the probe.

3. Apparatus as claimed in claim 2, wherein said expansible structure further includes a structural balloon having an interior space encompassing the ultrasonic emitter, said probe having a structural balloon conduit communicating with said structural balloon and extending to a location adjacent the proximal end of the probe.

4. Apparatus as claimed in claim 3, wherein said structural balloon is contiguous with said reflector balloon at said active region when said expansible structure is in said expanded condition.

5. Apparatus as claimed in claim 4, wherein said structural balloon and said reflector balloon have a common wall separating their interior spaces at said active region, whereby said reflective interface will be formed at said common wall.

6. Apparatus as claimed in claim 3, wherein said structural balloon has a transmissive wall adapted to overlie a wall of an internal organ of a subject when said expansible structure is in said expanded condition, and said active region is configured so that ultrasonic energy will be reflected from said active region, through the interior space of the structural balloon to said transmissive wall, so that the ultrasonic energy will pass through the transmissive wall to the wall of the internal organ.

7. Apparatus as claimed in claim 1, wherein said ultrasonic emitter is substantially in the form of a surface of revolution about a central axis extending in forward and rearward directions, and the active region is also substantially in the form of a surface of revolution about said central axis when said expansible structure is in said expanded condition.

8. Apparatus as claimed in claim 7, wherein the surface of revolution formed by the active region slopes generally forwardly in a radially outward direction away from said central axis.

9. Apparatus as claimed in claim 8, wherein said active surface is adapted to focus the ultrasonic energy reflected at the active surface into a loop-like focal region having area smaller than the active region.

10. Apparatus as claimed in claim 8, wherein said surface of revolution has a generatrix substantially in the form of a portion of a parabola having a principal axis, the principal axis of said parabola being transverse to said central axis.

11. Apparatus as claimed in claim 7, further comprising a lens having a refractive surface substantially in the form of a surface of revolution about said central axis surrounding said emitter, said lens focusing ultrasonic energy directed from said emitter toward said active region.

12. Apparatus as claimed in claim 11, wherein said lens is an inflatable lens including a lens balloon having an interior space, the probe further having a lens balloon conduit communicating with the interior space of the lens balloon.

13. Apparatus as claimed in claim 1, wherein said active region is configured so that ultrasonic energy reflected at said active region when said expansible structure is in said expanded condition will be focused into a focal region smaller than the active region.

14. Apparatus as claimed in claim 1, wherein said expansible structure is operative to direct the energy substantially to a region immediately surrounding a point.

16. Apparatus as claimed in claim 15, wherein said active region of said reflector is configured so that said reflector will focus the energy reflected at said active region.

17. Apparatus as claimed in claim 15, further comprising an elongated probe having a proximal end and a distal end adapted for insertion into the body of the patient, said expansible structure being mounted on said probe adjacent the distal end thereof.

18. Apparatus as claimed in claim 16, wherein said expansible structure includes a first balloon, said expansible structure being movable between said collapsed condition and said expanded condition by inflating said first balloon.

19. Apparatus as claimed in claim 18, wherein said reflector structure further includes a second balloon disposed adjacent said first balloon.

20. Apparatus as claimed in claim 19, wherein said first and second balloons include a common wall which forms a portion of said first balloon and a portion of said second balloon, so that the interiors of said first and second balloons are separated from one another by said common wall at said active region.

21. Apparatus as claimed in claim 19, wherein said probe includes a first conduit communicating with the interior of the first balloon and a second conduit in one of said catheters communicating with the interior of the second balloon, whereby said first and second balloons can be filled with different fluids.

22. Apparatus as claimed in claim 19, wherein said emitter is disposed inside the first balloon when the first balloon is in the expanded condition.

23. Apparatus as claimed in claim 15, wherein said emitter is operative to apply electromagnetic radiation.

24. Apparatus as claimed claim 17, wherein said emitter includes a waveguide extending along said probe to adjacent the expansible structure.

25. Apparatus as claimed in claim 24, wherein the waveguide has a distal end, the waveguide being adapted to emit said electromagnetic energy from the distal end of the waveguide, the emitter further comprising an emitter redirecting element juxtaposed with the distal end of the waveguide so that the emitter redirecting element will reflect the energy emanating from the distal end of the waveguide onto said active region of said reflector.

26. Apparatus as claimed in claim 15, wherein said expansible structure further includes a reflective redirecting element, said redirecting element being juxtaposed with said active region so that energy reflected from said active region will impinge on said redirecting element and will be reflected by said redirecting element.

27. Apparatus as claimed in claim 17, wherein said probe includes one or more catheters having a proximal-to-distal direction, said first balloon and said active region extending along a first one of said one or more catheters generally in the proximal-to-distal direction of said first catheter, said emitter including an elongated emitter extending along said first catheter, said active region being adapted to reflect energy from said emitter into an elongated focal region extending generally parallel to the proximal-to-distal direction of said first catheter.

28. Apparatus as claimed in claim 1 or claim 15, wherein said expansible structure is operative to direct the energy into a treatment region in the form of an elongated path along a wall of an internal organ of the subject.

29. Apparatus as claimed in claim 28 wherein said elongated path is in the form of a substantially closed loop.

30. Apparatus as claimed in claim 28 wherein said expansible structure is operative to direct the energy through a surface of the wall of the organ and focus the energy in a focal region extending along said path within the wall at a depth from the surface of said wall.

31. Apparatus as claimed in claim 30, wherein said elongated path is in the form of a substantially closed loop.

32. Apparatus as claimed in claim 15, wherein said expansible structure is operative to direct the energy substantially to a region immediately surrounding a point.

33. Apparatus as claimed in claim 15, wherein said first balloon has a transmissive wall adapted to overlie the surface of an internal organ when said first balloon is in the inflated condition, said emitter being operative to provide said energy within the interior of the first balloon so that energy reflected from said active region will pass through the interior of the first balloon and will be transmitted to the tissue of the subject through said transmissive wall.

35. A reflector as claimed in claim 34, wherein at least a portion of the first active region is a common wall which forms a portion of each of said first and second balloons, so that the interiors of said first and second balloons are separated from one another by said common wall.

36. A reflector as claimed in claim 34, further comprising a liquid in said first balloon and a gas in said second balloon, whereby a reflective liquid-gas boundary forms said reflective interface at said first active region.

37. A reflector as claimed in claim 34, further comprising a third balloon, said second and third balloons being contiguous with one another at a second active region at least when said second and third balloons are in an inflated condition, and a third port communicating with the interior of the third balloon, whereby said first and second balloons can be filled with fluids of substantially the same acoustic impedance and said third balloon can be filled with a fluid of a different acoustic impedance to form a substantially non-reflective interface at said first active region and a substantially reflective interface at said second active region.

39. A method as claimed in claim 38, wherein said energy reflection at said active region focuses said energy.

40. A method as claimed in claim 38, wherein the energy is directed onto said active region so that the energy is directed into a treatment region of the wall of said organ in the form of an elongated path extending along the wall of said organ.

41. A method as claimed in claim 40 wherein the energy is directed so that said focal region extends along said path within the organ wall at a depth from the surface of the organ wall.

42. A method as claimed in claim 38, wherein said expansible structure includes a first balloon, said step of bringing said reflector structure to said expanded configuration including inflating said first balloon.

43. A method as claimed in claim 42, wherein said first balloon defines a transmissive wall, said positioning step including positioning said first balloon so that said transmissive wall lies adjacent the wall of the organ, and said energy is directed onto said active region from within said first balloon so that the energy is reflected at said active region through the interior of the first balloon and through the transmissive wall into said focal region.

44. A method as claimed in claim 43, wherein said positioning step includes positioning the first balloon so that the transmissive wall lies adjacent the wall of the organ.

45. A method as claimed in claim 44, wherein said positioning step includes positioning the first balloon so that the transmissive wall is spaced from the wall of the organ and maintaining a layer of liquid between the transmissive wall and the wall of the organ, whereby energy directed through the transmissive wall passes through the layer of liquid.

46. A method as claimed in claim 45, wherein said step of inflating said first balloon includes inflating said first balloon with a biocompatible inflation liquid and said step of maintaining a layer of liquid includes discharging the inflation liquid to the exterior of the first balloon so that at least some of the discharged inflation liquid passes between the transmissive wall and the wall of the organ.

47. A method as claimed in claim 43, wherein said step of directing energy includes directing ultrasonic energy towards said active region, said expansible structure includes a second balloon, and said step of expanding said expansible structure includes the step of inflating said first balloon with a first fluid having a first acoustic impedance and inflating said second balloon with a second fluid having a second acoustic impedance different from said first acoustic impedance to thereby form a first reflective interface at said active region.

48. A method as claimed in claim 47, wherein said first fluid has an acoustic impedance close to the acoustic impedance of tissue in said wall.

49. A method as claimed in claim 47, wherein said first fluid is a liquid and said second fluid is a gas.

50. A method as claimed in claim 49, further comprising the step of detecting the disposition of said reflector structure by imaging the subject using an imaging modality in which said gas-filled second balloon provides contrast.

51. A method as claimed in claim 47, wherein said reflector structure includes a third balloon, the method further comprising the steps of inflating said second balloon with a fluid having acoustic impedance substantially equal to said first acoustic impedance and inflating said third balloon with a fluid having acoustic impedance different from said first acoustic impedance to provide at said first active region and to provide an interface at a second active region having reflectivity greater than the reflectivity of the interface at said first active region, and directing the ultrasonic energy onto said second active region so that the ultrasonic energy is reflected from said second active region into a second focal region different from the first focal region.

52. A method as claimed in claim 42, wherein said positioning step is performed so as to position said first balloon within a chamber of the heart and said path along a wall of the heart, and wherein said energy ablates tissue in the wall of the heart so as to form a first conduction block extending along said elongated path.

53. A method as claimed in claim 52, wherein said positioning step is performed so as to position said first balloon within a chamber of the heart and said path extends along the wall of the heart and at least partially around a first ostium of a first blood vessel communicating with such chamber.

54. A method as claimed in claim 53, wherein said first blood vessel is a pulmonary vein, said first ostium being disposed adjacent an opening of an atrial appendage, the method further comprising forming a second conduction block extending at least partially around the opening of the atrial appendage so that first and second conduction blocks cooperatively encompass and isolate a region of the heart wall including said first ostium and said opening of said atrial appendage.

55. A method as claimed in claim 53, wherein said path is substantially in the form of a closed loop encircling said first ostium.

56. A method as claimed in claim 40, wherein said step of directing energy is performed so as to direct the energy into said focal region along substantially the entire elongated path simultaneously.

57. A method as claimed in claim 38, wherein said energy-directing step includes directing the energy through an inflatable lens and varying the configuration of said inflatable lens so as to vary the location of said focal region.

58. A method as claimed in claim 38, wherein said energy-directing step includes directing the energy from a source to said active region and varying the positional relationship between said source and said active region so as to vary the location of said focal region.

60. A method as claimed in claim 59 wherein said energy-applying step is performed so as to apply energy along substantially the entire path simultaneously.

15. Apparatus for applying energy within the body of a living subject comprising:

(a) an expansible structure for insertion into the body of the subject, the expansible structure including a reflector having an active region, the expansible structure having a collapsed condition and an expanded condition, said expansible structure including a reflector having an active region;

(b) an energy emitter operative to apply energy while the expansible structure is in the expanded condition and disposed within the body of the subject so that the applied energy is directed onto the active region of the reflector and reflected by the active region of the reflector towards the tissue of the subject adjacent the reflector, said expansible structure being operative to focus the energy.

34. A reflector for directing ultrasonic energy comprising a first balloon and a second balloon, said balloons being inflatable and deflatable, said balloons being contiguous with one another at a first active region at least when said balloons are in an inflated condition, and a first port communicating with the interior of the first balloon and a second port communicating with the interior of the second balloon, whereby said first and second balloons can be filled with different fluids having different acoustic impedances so as to form a reflective interface at said first active region.

38. A method of applying energy to the wall of an internal organ of a living subject comprising the steps of:

(a) positioning an expansible structure within the body of the subject in or adjacent to said organ and bringing said expansible structure to an expanded condition; and

(b) directing energy onto an active region of said expansible structure so that energy is reflected from said active region and directed onto the wall of the internal organ, said expansible structure focusing said energy in a focal region.

59. A method of forming a conduction block in the wall of a heart of a mammalian subject comprising the steps of:

(a) applying energy to a treatment region extending along a loop-like path at least partially encircling a region so as to ablate tissue along said region;

(b) detecting electrophysiologic signals within said region; and

(c) terminating said energy-applying step in response to a change in said electrophysiologic signals.

61. Apparatus for applying energy to the wall of an internal organ of a mammalian subject, said apparatus comprising:

(a) a probe having a proximal end and a distal end adapted for insertion into the body of the subject, said probe having an inflation conduit extending from adjacent the proximal end to adjacent the distal end;

(b) a structural balloon having an interior space and a transmissive wall having an interior surface bounding said interior space and an exterior surface, said structural balloon being mounted to said probe adjacent the distal end thereof, said interior space communicating with said inflation conduit, said structural balloon being mounted to said probe so that said transmissive wall will be juxtaposed with the wall of the organ to be treated when the structural balloon is inflated;

(c) an emitter mounted to said probe within said structural balloon, said emitter being arranged to supply energy so that said energy will be directed through said transmissive wall; and

(d) at least one fluid outlet port having an inlet communicating with the interior space of said structural balloon, said fluid outlet port having an outlet at or adjacent the exterior surface of the transmissive wall, whereby said structural balloon can be maintained in an inflated condition and with a layer of fluid separating said transmissive wall from the wall of the organ by passing an inflation fluid through said inflation conduit into said interior space and through the at least one fluid outlet port to the outside of the transmissive wall.

62. Apparatus as claimed in claim 61, wherein said transmissive wall is porous and said at least one fluid outlet port includes a multiplicity of pores in said transmissive wall.

63. Apparatus as claimed in claim 61, wherein said emitter is mounted to said probe so that inflation fluid flowing from said inflation conduit to said at least one outlet port passes through or adjacent to said emitter.

64. Apparatus as claimed in claim 61, wherein said emitter is an ultrasonic emitter.

65. Apparatus for treating an internal organ of a mammalian subject, said apparatus comprising:

(a) a probe having a proximal end and a distal end adapted for insertion into the body of the subject, said probe including a carrier catheter defining a central axis;

(b) a balloon having a proximal end attached to said carrier catheter and having a distal end, said probe having an inflation conduit communicating with the interior of said balloon; and

(c) means for moving said distal end of said balloon distally relative to the proximal end of the balloon, whereby the balloon can be inflated when the carrier catheter is in the extended position by introducing a fluid through said inflation conduit and then deflated by withdrawing the fluid through the inflation conduit, and the balloon can be elongated in the proximal-to-distal direction by operation of said means for moving so as to substantially collapse the balloon in radial directions transverse to the central axis to facilitate movement of the carrier catheter in the proximal direction.

66. Apparatus as claimed in claim 65, wherein said means for moving includes a resilient element biasing said distal end of said balloon away from the proximal end of the balloon.

67. Apparatus as claimed in claim 66 wherein said resilient element is a spring disposed inside said balloon, said spring having a proximal end mechanically coupled to said carrier catheter and a distal end mechanically coupled to the distal end of said balloon, said spring including a plurality of coils encircling said central axis of said balloon, said spring being in a collapsed condition when said balloon is inflated, said coils engaging one another in said collapsed condition so that said spring resists deformation transverse to central axis, whereby said spring in said collapsed condition maintains said balloon in a predetermined orientation relative to the central axis of the carrier catheter.

68. Apparatus as claimed in claim 67 further comprising an energy emitter disposed within said balloon and mechanically connected to said carrier catheter.

69. Apparatus as claimed in claim 68 wherein said energy emitter has a proximal end mounted to said carrier catheter and a distal end, said coil spring extending between said distal end of said energy emitter and said distal end of said balloon so that said coil spring is mechanically connected to said carrier catheter through said energy emitter.

70. Apparatus as claimed in claim 65, wherein said means for moving includes a guide member slidably mounted in said carrier catheter, said distal end of said balloon being attached to said guide member.

71. Apparatus as claimed in claim 65, wherein said means for moving is also operative to rotate the distal end of the balloon relative to the proximal end of the balloon.

72. Apparatus as claimed in claim 65, wherein said probe further includes an introducer catheter having an internal bore, said carrier catheter being slidably mounted in the internal bore of the introducer catheter for movement between a retracted position in which said balloon is disposed within said internal bore and an extended position in which said balloon is disposed outside of said internal bore.

73. Apparatus for treating an internal organ of a mammalian subject, said apparatus comprising:

(a) a probe having a proximal end and a distal end adapted for insertion into the body of the subject, said probe including a carrier catheter defining a central axis;

(b) a balloon having a proximal end attached to said carrier catheter and having a distal end, said probe having an inflation conduit communicating with the interior of said balloon; and

(c) means for twisting said distal end of said balloon relative to the proximal end of the balloon about said central axis, whereby the balloon can be inflated when the carrier catheter is in the extended position by introducing a fluid through said inflation conduit and then deflated by withdrawing the fluid through the inflation conduit, and the balloon can be substantially collapsed in radial directions transverse to the central axis to facilitate movement of the carrier catheter in the proximal direction.

74. Apparatus as claimed in claim 73, wherein said means for moving includes a guide member slidably mounted in said carrier catheter, said distal end of said balloon being attached to said guide member.

75. Apparatus as claimed in claim 73, wherein said probe further includes an introducer catheter having an internal bore, said carrier catheter being slidably mounted in the internal bore of the introducer catheter for movement between a retracted position in which said balloon is disposed within said internal bore and an extended position in which said balloon is disposed outside of said internal bore.

76. Apparatus for treating an internal organ of a mammalian subject, said apparatus comprising:

(a) a probe having a proximal end and a distal end adapted for insertion into the body of the subject, said probe including a carrier catheter;

(b) a balloon having a proximal end attached to said carrier catheter adjacent the distal end of the probe, said probe having an inflation conduit communicating with the interior of said balloon so that said balloon can be inflated and deflated;

(c) a skirt member having a body defining a skirt axis and a plurality of limbs disposed around said skirt axis, each limb having a proximal end pivotably connected to the body of the skirt member and a distal end remote from the proximal end, said limbs being movable between a collapsed condition in which the distal ends of the limbs are adjacent said skirt axis and an expanded condition in which the limbs slope radially outwardly, away from said skirt axis, in the distal direction, the proximal end of the balloon being disposed between said limbs of skirt member and distal to the body of the skirt member in a withdrawal-preparation condition.

77. Apparatus as claimed in claim 76, wherein said skirt member and said carrier catheter are slidable relative to one another in the proximal-to-distal direction.

78. Apparatus as claimed in claim 77, further comprising an introducer carrier having a distal end and an internal bore with an opening at the distal end, said skirt member having an internal bore extending between the proximal ends of said limbs, said skirt member being slidably mounted in said internal bore of said introducer catheter for movement between a retracted position in which said limbs are at least partially disposed within the introducer catheter and an advanced position in which the proximal ends of said limbs are distal to the introducer catheter, said carrier catheter being slidably mounted in the internal bore of the skirt member for movement between a retracted position in which at least the proximal end of said balloon is disposed within said introducer catheter and an advanced position in which said balloon is disposed distal to said introducer catheter.

80. A medical device comprising an operative portion and an anchor balloon as claimed in claim 79, said operative portion being linked to the proximal end of the proximal portion of said anchor balloon, whereby when the anchor balloon is positioned within a tubular anatomical structure, a portion of the balloon adjacent the boundary will engage the wall of such structure and the proximal end of the proximal portion will be urged in the distal direction, thereby urging the operative structure in the distal direction.

79. An anchor balloon for positioning a medical treatment device within the body of a subject, said balloon comprising a proximal portion and a distal portion, said portions having walls generally in the form of surfaces of revolution about a common central axis joining one another at a boundary encircling said central axis, said portions being elongated in the direction along said central axis when the balloon is in a deflated condition, said proximal portion having a proximal end remote from the boundary, said proximal portion being less readily distensible than said distal portion, whereby when the balloon is inflated the proximal portion of the balloon will deform to a generally disk-like configuration and the axial dimension of the balloon between the boundary and the proximal end of the proximal portion will decrease.