Laser-driven acoustic ablation catheter

• US 6,203,537 B1
• Filed: 02/04/1999
• Issued: 03/20/2001
• Est. Priority Date: 02/04/1999
• Status: Expired due to Fees

• Current Assignee: Sorin Adrian
• Original Assignee: Sorin Adrian
• Inventors: Adrian, Sorin
• Primary Examiner(s): COHEN, LEE S
• Application Number:
  US09/244,850
• Time in Patent Office: 775 Days
• Field of Search: 606/3, 606/7, 606/13, 606/15, 606/17, 606/128, 606/171, 606/2.5, 606/1, 604/20, 604/21, 604/35, 604/523, 604/22, 601/4, 600/439
• US Class Current: 606/1
• CPC Class Codes: A61B 18/26 for producing a shock wave, e.g. laser lithotripsy
• CPC Class Codes: A61B 2017/00172 Pulse trains, bursts, intermittent continuous operation
• CPC Class Codes: A61B 2018/0019 vibrating
• CPC Class Codes: A61B 2018/00196 reciprocating lengthwise
• CPC Class Codes: A61B 2018/266 the conversion of laser energy into mechanical shockwaves taking place in a part of the probe

Abstract

An acoustic ablation catheter includes a mass cap mounted by a spring at the distal end of the catheter, to thereby form a structure capable of axial motion with a resonant frequency. The mass cap defines an aperture which may be used for a guide wire, for aspiration/infusion, or both. Acoustic motion of the resonant structure is generated by sources of laser light spaced about the distal end of the flexible portion of the catheter body, which produce laser light beams which produce microexplosions adjacent the proximal end of the mass cap. The sources of laser light beams may be laser chips located at the distal end of the body, or they may be the distal ends of optical fibers extending through the body from laser light generators outside the catheter itself. In one advantageous embodiment, relative motion is introduced between the mass cap and the light beams, so that erosion is distributed over a track. At least that portion of the mass cap upon which the laser light pulses impinge is made from titanium.

Claims

1. An ablation apparatus including a catheter, said catheter comprising:

an elongated, flexible body defining a distal end, a proximal end, and a local axis;

a mass cap defining a proximal portion and a distal portion;

resilient mounting means including a proximal end and a distal end, said proximal end of said resilient mounting means being physically coupled to said distal end of said body of said catheter, and said distal end of said resilient mounting means being physically coupled to said mass cap, for holding said mass cap adjacent to said distal end of said body of said catheter, said resilient mounting means defining at least one of transparent and open regions lying between said distal end of said catheter body and said mass cap;

said ablation apparatus further comprising

at least one laser light source for producing a light beam, and located near said distal end of said catheter body, and oriented so as to project its light beam parallel to said local axis, through said resilient mounting means, to a proximal portion of said mass cap;

wherein;

said mass cap in conjunction with said resilient mounting means makes a physically resonant system defining a fundamental resonant frequency; and

further comprising;

a laser light source driving arrangement, said laser light source driving arrangement including means for driving said at least one laser light source, for generating said laser light in pulses having a repetition rate which is near one of (a) said fundamental frequency and (b) a subharmonic of said fundamental frequency, and for, together with said ablation catheter, forming an ablation catheter system.

2. A catheter according to claim 1, wherein said laser light source comprises at least one semiconductor laser chip, and further comprising electrical conducting means extending from said semiconductor laser chip to said proximal end of said body of said catheter.

3. A catheter according to claim 1, wherein said laser light source comprises:

a laser located outside said body of said catheter;

a source of electrical energy coupled to said laser by means lying outside of said catheter body; and

an optical fiber light path extending from said laser through said proximal end of said body of said catheter, through said body of said catheter and to said distal end of said catheter body.

4. A catheter according to claim 1, wherein:

said mass cap further defines an aperture;

said body of said catheter defines a lumen extending from a region near said proximal end of said catheter body to said distal end of said catheter body; and

said resilient mounting means also defines a light path extending from said aperture of said mass cap to the distal end of said lumen of said catheter body.

5. A catheter according to claim 4, wherein:

said laser light source comprises a plurality of locations adjacent said distal end of said catheter body at which laser light beams emanate parallel to said local axis; and

said aperture of said mass cap, said path of said resilient mounting means, and that portion of said lumen of said catheter body near said distal end of said catheter body are radially centered between said plurality of locations at which said laser light beams emanate.

6. A catheter according to claim 4, wherein:

said mass cap defines a further aspiration/infusion aperture;

said body of said catheter defines a further aspiration/infusion lumen extending from a region near said proximal end of said catheter body to said distal end of said catheter body.

7. An ablation catheter according to claim 1, further comprising focussing means coupled to said light beam for focussing said light beam onto said proximal portion of said mass cap.

8. An ablation catheter according to claim 1, further comprising moving means for moving in a manner which results in relative motion of the point of impingement of said light beam on said mass cap over time.

9. An ablation catheter according to claim 8, wherein said moving means comprises means coupled to said mass cap for causing said mass cap to rotate.

10. An ablation catheter according to claim 9, wherein said moving means comprises a fluidic motor coupled to said mass cap.

11. An ablation catheter according to claim 10, wherein said fluidic motor includes an axial aperture extending through said mass cap, and impeller blades associated with said aperture, for causing a rotational moment on said mass cap in response to the flow of fluid through said aperture.

12. An ablation catheter, comprising:

an elongated, flexible body defining a distal end, a proximal end, and a local axis;

a mass cap defining a proximal portion and a distal portion;

a resilient mounting arrangement including a proximal end and a distal end, said proximal end of said resilient mounting arrangement being physically coupled to said distal end of said body of said catheter, and said distal end of said resilient mounting arrangement being physically coupled to said mass cap, for holding said mass cap adjacent to said distal end of said catheter body, said resilient mounting arrangement defining one of transparent and open regions lying between said distal end of said catheter body and said mass cap; and

a plurality of laser light sources, each of which produces a light beam, each of said laser light sources being physically coupled to said distal end of said catheter body, each of said plurality of laser light sources being circumferentially located relative to said local axis, and equally spaced about said local axis relative to others of said laser light sources, so as to project its light beam parallel to said local axis, through a transparent region of said resilient mounting arrangement, to a proximal portion of said mass cap.

13. An ablation catheter system, comprising:

an elongated, flexible body defining a distal end, a proximal end, and a local axis;

a mass cap defining a proximal portion and a distal portion;

a resilient mounting arrangement including a proximal end and a distal end, said proximal end of said resilient mounting arrangement being physically coupled to said distal end of said body of said catheter, and said distal end of said resilient mounting arrangement being physically coupled to said mass cap, for holding said mass cap adjacent to said distal end of said catheter body, said resilient mounting arrangement defining one of transparent and open regions lying between said distal end of said catheter body and said mass cap; and

a plurality of laser light sources, each of which produces a light beam, each of said laser light sources being physically coupled to said distal end of said catheter body, each of said plurality of laser light sources being circumferentially located relative to said local axis, and equally spaced about said local axis relative to others of said laser light sources, so as to project its light beam parallel to said local axis, through a transparent region of said resilient mounting arrangement, to a proximal portion of said mass cap;

wherein;

said mass cap in conjunction with said resilient mounting arrangement makes a physically resonant system defining a fundamental resonant frequency;

said ablation catheter system further comprising;

a laser light source driving arrangement, said laser light source driving arrangement including means for driving said laser light sources, for generating said laser light in pulses having a repetition rate which is near one of said fundamental frequency and harmonics of said fundamental frequency.

14. An ablation catheter system according to claim 13, wherein said laser light sources comprise semiconductor laser chips, and further comprise electrical conducting means extending from said semiconductor laser chips to said proximal end of said body of said catheter.

15. An ablation catheter system according to claim 13, wherein each of said laser light sources comprises:

a laser located outside said body of said catheter; and

an optical fiber light path extending from said laser through said proximal end of said catheter, through said body of said catheter and to said distal end of said catheter body.

16. An ablation catheter system according to claim 13, wherein:

said mass cap further defines an aperture;

said body of said catheter defines a lumen extending from a region near said proximal end of said catheter body to said distal end of said catheter body; and

said resilient mounting arrangement also defines a path extending from said aperture of said mass cap to said lumen at said distal end of said catheter body.

17. An ablation catheter system according to claim 16, wherein said aperture of said mass cap, said path of said resilient mounting arrangement, and that portion of said lumen of said catheter body near said distal end of said catheter body are radially centered between said laser light sources.

18. An ablation catheter system according to claim 16, wherein:

said mass cap further defines a further aspiration/infusion aperture;

said body of said catheter defines a further aspiration/infusion lumen extending from a region near said proximal end of said catheter body to said distal end of said catheter body.

19. An ablation catheter, comprising:

an elongated, flexible body defining a distal end, a proximal end, and a local axis, and also defining a lumen extending from a region near said proximal end of said catheter body to said distal end of said catheter body;

a mass cap defining a proximal portion and a distal portion, and also defining a central aperture extending from said proximal portion to said distal portion of said mass cap;

a resilient mounting arrangement including a proximal end and a distal end, said proximal end of said resilient mounting arrangement being physically coupled to said distal end of said body of said catheter, and said distal end of said resilient mounting arrangement being physically coupled to said mass cap, for holding said mass cap adjacent to said distal end of said catheter body with said central aperture coaxial with said local axis, said resilient mounting arrangement defining transparent regions lying between said distal end of said catheter body and said mass cap;

a plurality of laser light sources, each of which produces a light beam, each of said laser light sources being physically coupled to said distal end of said catheter body, each of said plurality of laser light sources being circumferentially located relative to said local axis, and equally spaced about said local axis relative to others of said laser light sources, so as to project its light beam parallel to said local axis, through a transparent region of said resilient mounting arrangement, to a proximal portion of said mass cap.

20. An ablation catheter according to claim 19, wherein said resilient mounting arrangement also defines an open path extending from said aperture at said proximal end of said mass cap to said lumen at said distal end of said catheter body.

21. An ablation catheter including an elongated, flexible body defining a distal end, a proximal end, and a local axis;

a mass cap defining a proximal portion of a particular material and a distal portion of a material other than said particular material;

a resilient mounting arrangement including a proximal end and a distal end, said proximal end of said resilient mounting arrangement being physically coupled to said body of said catheter, and said distal end of said resilient mounting arrangement being physically coupled to said mass cap, for holding said mass cap adjacent to said distal end of said catheter body, said resilient mounting arrangement defining at least one of transparent and open regions lying between said distal end of said catheter body and said mass cap; and

a light source for producing a light beam, and located near said distal end of said catheter body, and oriented so as to project its light beam parallel to said local axis, through said resilient mounting arrangement, to a proximal portion of said mass cap.

22. An ablation catheter according to claim 21, wherein said particular material is titanium.