Photoablation with infrared radiation

• US 20020068924A1
• Filed: 08/07/2001
• Published: 06/06/2002
• Est. Priority Date: 09/09/1994
• Status: Active Grant

• Current Assignee: Cardiofocus Incorporated
• Original Assignee: Cardiofocus Incorporated
• Inventors: Sinofsky, Edward L.
• Granted Patent: US 6,579,285 B2
• Time in Patent Office: Days
• US Class Current: 606/3
• CPC Class Codes: A61B 18/22 the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/2261 with scattering, diffusion or dispersion of light
• CPC Class Codes: A61B 2018/2272 with reflective or refractive surfaces for deflecting the beam A61B2018/2261, A61B2018/2266 take precedence
• CPC Class Codes: A61B 2018/2288 the optical fibre cable having a curved distal end
• CPC Class Codes: A61L 2/10 Ultraviolet radiation
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61N 5/0601 Apparatus for use inside the body
• CPC Class Codes: C08L 27/12 containing fluorine atoms

Abstract

Infrared surgical photoablation instruments are disclosed for creating lesions in tissue, including cardiac tissue for treatment of arrhythmias and other diseases. The hand held instruments are especially useful in open chest or port access cardiac surgery for rapid and efficient creation of curvilinear lesions to serve as conduction blocks. Photoablative instruments are disclosed that emit radiation at a wavelength in a range from about 800 nm to about 1000 nm, and preferably emit at a wavelength in a range of about 915 nm to about 980 nm. Radiation at a wavelength of 915 nm or 980 nm is commonly preferred, in some applications, because of the optimal absorption of infrared radiation by cardiac tissue at these wavelengths.

Claims

1. A surgical ablation instrument comprising:

a housing having at least one lumen therein and having a distal portion that is at least partially transmissive to photoablative light; and

a light delivery element disposable within the lumen of the housing and adapted to delivery infrared radiant energy through a transmissive region of the housing to a target tissue site.

2. The instrument of claim 1, wherein the instrument further comprises a light source for generating photoablative radiation at a desired wavelength ranging from about 800 nm to about 1000 nm

3. The instrument of claim 1, wherein the instrument further comprises a light source for generating photoablative radiation at desired wavelengths ranging from between about 915 mn and about 980 nm.

4. The instrument of claim 1, wherein the instrument further comprises a light source for generating photoablative radiation at a wavelength of about 915 nm.

5. The instrument of claim 1, wherein the instrument further comprises a light source for generating photoablative radiation at a wavelength of about 980 nm.

6. The instrument of claim 1, wherein the light delivering element further comprises a light transmitting optical fiber adapted to receive ablative light from a light source and a light emitting tip at a distal end of the fiber for emitting diffuse light.

7. The instrument of claim 1, wherein the light delivering element further comprises a light transmitting optical fiber adapted to receive ablative light from a light source and a light emitting tip at a distal end of the fiber for emitting defocused light.

8. The ablation instrument of claim 1, wherein the housing has a curved distal portion with at least one lumen therein and the light delivering element is disposable within the lumen of the curved portion for delivering ablative light to form a curvilinear lesion at a target tissue site adjacent to the housing.

9. The instrument of claim 1, wherein the light delivering element is slidably disposed within the inner lumen of the housing and the instrument further comprises a translatory mechanism for disposing the tip of the light delivering element at one or more of a plurality of locations with the housing.

10. The instrument of claim 9, wherein the light emitting tip comprises:

a hollow tube having a proximal end joined to the light transmitting optical fiber, a closed distal end, and an inner space defining a chamber therebetween; and

a light scattering medium disposed within the chamber to distribute light propagating through the fiber through the transmissive region of the housing toward a target site in an elongated pattern,

11. The apparatus of claim 10, wherein the light scattering medium comprises a polymeric or liquid material having light scattering particles incorporated therein.

12. The instrument of claim 11, wherein the light scattering particles are chosen from the group consisting of alumina, silica, and titania compounds and mixtures thereof.

13. The instrument of claim 10, wherein the distal end of the tube includes a reflective end such that the scattering medium and the reflective end interact to provide a substantially uniform axial distribution of light over the length of the housing.

14. The instrument of claim 2, wherein the light emitting tip further comprises at least one reflector for directing the light through the transmissive region of the housing toward a target site.

15. The instrument of claim 2, wherein the light emitting tip further comprises at least one defocusing lens for distributing the light in a pattern.

16. The instrument of claim 2, wherein the light emitting tip further comprises at least one longitudinal optical element such that the light distributed by the tip is confined to desired angular distribution.

17. The instrument of claim 1, wherein the distal portion of the instrument has an open loop shape so as to allow the loop to be placed around at least one a pulmonary vein.

18. The instrument of claim 17, wherein the distal portion of housing can be shaped into a curve having a radius between about 5 and 25 mm.

19. The instrument of claim 17, wherein the instrument further comprises at least one malleable strip element disposed at the distal portion of the housing.

20. The instrument of claim 1, further comprising an expandable balloon disposed about a distal portion of the housing, and a sheath disposed about the expandable balloon and having at least one open section for providing irrigation to a treatment site.

21. The instrument of claim 20, wherein the expandable balloon has a predetermined shape in its expanded form such that, when inflated, the balloon engages and is in direct contact with a the tissue of a body lumen.

22. The instrument of claim 20, wherein the housing includes at least one conduit for the delivery of a fluid to the expandable balloon.

23. The instrument of claim 20, wherein the housing includes a conduit for the delivery of irrigation fluid between the expandable balloon and the outer sheath.

24. The instrument of claim 20, wherein the expandable balloon, when fully expanded, provides a transmission pathway for radiant energy.

26. The method of claim 25, wherein the method further comprises generating photoablative radiation at a desired wavelength ranging from about 800 mn to about 1000 nm

27. The method of claim 25, wherein the method further comprises generating photoablative radiation at a desired wavelength ranging from about 915 nm to about 980 nm.

28. The method of claim 25, wherein the method further comprises generating photoablative radiation at a wavelength of about 915 nm.

29. The method of claim 28, wherein the distal portion of the photoablation instrument is positioned epicardially.

30. The method of claim 25, wherein the method further comprises generating photoablative radiation at a wavelength of about 980 nm.

31. The method of claim 30, wherein the distal portion of the photoablation instrument is positioned endocardially.

32. The method of claim 25, wherein the method further comprises distributing the photoablative radiation in an elongated pattern.

33. The method of claim 25, wherein the instrument is curved and the method further comprises distributing the photoablative radiation in an elongated arcuate pattern.

34. The method of claim 25, wherein the distal portion of the instrument has an open loop shape and the method further comprises placing the loop around at least one a pulmonary vein.

35. The method of claim 25, wherein the distal end of the instrument is malleable and the method further comprises shaping the distal end into a curve having a radius between about 5 and 25 mm.

36. The method of claim 25, wherein the method further comprises:

repeating the steps of positioning and exposing until a composite lesion of a desired shape is formed.

25. A method of ablating cardiac tissue, comprising:

positioning a distal portion of a photoablation instrument in proximity to a target region of cardiac tissue, the instrument having a hollow housing and a light delivering element coupled to a source of photoablative radiation and disposed within the distal portion, the distal portion being transmissive to ablative infrared radiation to permit the distribution of radiation by the light emitting element in a pattern;

activating the light emitting element to transmit infrared radiant energy through the housing to expose the target region.

37. A method of treating cardiac arrhythmias, comprising:

positioning an ablation instrument in proximity to a target cardiac treatment site, the instrument including a source of penetrating energy; and

activating the instrument to transmit penetrating energy into tissue at the target site to form a lesion by uniform heating of the target tissue.