DEVICES AND METHODS FOR DELIVERING FLUID TO TISSUE DURING ABLATION THERAPY

• US 20180042669A1
• Filed: 07/31/2017
• Published: 02/15/2018
• Est. Priority Date: 08/11/2016
• Status: Active Grant

• Current Assignee: Thermedical, Inc.
• Original Assignee: Thermedical, Inc.
• Inventors: Curley, Michael G., Eberl, Gregory R., Clevenger, Jason M., Howard, Michael T., Delly, Erik
• Granted Patent: US 11,013,555 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 18/04 by heating by applying electromagnetic radiation A61B18/18; hyperthermia using electric or magnetic fields, radiation or ultrasound A61N
• CPC Class Codes: A61B 18/1477 Needle-like probes
• 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 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00714 Temperature
• CPC Class Codes: A61B 2018/00744 Fluid flow
• CPC Class Codes: A61B 2018/046 in liquid form
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

Devices and methods for delivering fluid to tissue during ablation therapy are described herein. An exemplary device can include an elongate body having an inner lumen, outlet ports, and an ablation element configured to heat tissue. A flow resistance of the elongate body can increase along a length of the elongate body containing the outlet ports in a proximal to distal direction. This can be accomplished by, for example, varying outlet port size or relative spacing, decreasing a cross-sectional area of the inner lumen through which fluid can flow using a flow diverter or tapered inner lumen sidewalls, or limiting a ratio between a total area of the outlet ports and a cross-sectional area of the inner lumen. Adjusting flow resistance of the elongate body can provide more uniform fluid distribution or a desired non-uniform distribution.

Claims

1. An ablation device, comprising:

an elongate body having an inner lumen;

a plurality of outlet ports formed in the elongate body and disposed along a length thereof, the plurality of outlet ports being configured to deliver fluid from the inner lumen to tissue surrounding the elongate body; and

an ablation element configured to heat the tissue surrounding the elongate body;

wherein a flow resistance of the elongate body increases along the length of the elongate body containing the plurality of outlet ports from a proximal end thereof to a distal end thereof.

2. The device of claim 1, wherein the flow resistance of the elongate body includes any of a flow resistance per unit length of inner lumen and a resistance to fluid flow from the lumen through the plurality of outlet ports.

3. The device of claim 1, wherein a ratio of a sum of an area of each of the plurality of outlet ports to an area of the inner lumen is less than about 3:

1.

4. The device of claim 1, wherein the flow resistance to fluid flow through a distal 25% of the plurality of outlet ports is such that they deliver less than about 70% by volume of fluid delivered into tissue from the plurality of outlet ports.

5. The device of claim 1, wherein the flow resistance to fluid flow through a distal 25% of the plurality of outlet ports is such that they deliver less than about 55% by volume of fluid delivered into tissue from the plurality of outlet ports.

6. The device of claim 1, wherein the flow resistance to fluid flow through a distal 25% of the plurality of outlet ports is such that they deliver less than about 40% by volume of fluid delivered into tissue from the plurality of outlet ports.

7. The device of claim 1, wherein a cross-sectional area of each of the plurality of outlet ports decreases from a proximal end of the elongate body to a distal end of the elongate body.

8. The device of claim 1, wherein spacing between adjacent axially-aligned outlet ports increases from a proximal end of the elongate body to a distal end of the elongate body.

9. The device of claim 1, wherein at least one of the plurality of outlet ports has a non-circular shape.

10. The device of claim 1, wherein at least one of the plurality of outlet ports has a slot shape.

11. The device of claim 1, further comprising:

a flow diverter disposed within the inner lumen of the elongate body along the length of the elongate body containing the plurality of outlet ports;

wherein a diameter of the flow diverter increases from a proximal end thereof to a distal end thereof.

12. The device of claim 1, wherein the ablation element is a radio frequency electrode disposed along a length of the elongate body;

and

wherein the device includes at least one outlet port positioned at least partially beyond a boundary of the ablation element to deliver fluid to tissue immediately adjacent to the boundary of the ablation element.

13. An ablation device, comprising:

an elongate body having an inner lumen, the elongate body including a fluid delivery portion extending along a length thereof, the fluid delivery portion having a plurality of outlet ports configured to deliver fluid from the inner lumen to tissue surrounding the elongate body; and

an ablation element configured to heat tissue surrounding the elongate body;

wherein the fluid delivery portion of the elongate body is configured such that less than about 70% by volume of fluid delivered to tissue is emitted from outlet ports disposed in a distal 25% of the fluid delivery portion.

14. The device of claim 13, wherein the fluid delivery portion is further configured such that less than about 55% by volume of fluid delivered to tissue is emitted from outlet ports disposed in a distal 25% of the fluid delivery portion.

15. The device of claim 13, wherein the fluid delivery portion is further configured such that less than about 70% by volume of fluid delivered to tissue is emitted from outlet ports disposed in a proximal 25% of the fluid delivery portion.

16. The device of claim 13, wherein the fluid delivery portion is further configured such that less than about 55% by volume of fluid delivered to tissue is emitted from outlet ports disposed in a proximal 25% of the fluid delivery portion.

17. The device of claim 13, wherein the fluid delivery portion is further configured such that less than about 70% by volume of fluid delivered to tissue is emitted from outlet ports disposed in a central 50% of the fluid delivery portion.

18. An ablation device, comprising:

a catheter-delivered elongate body having an inner lumen;

a plurality of outlet ports formed in the elongate body, each of the plurality of outlet ports defining an area configured to pass fluid from the inner lumen to tissue surrounding the elongate body; and

an ablation element configured to heat the tissue surrounding the elongate body;

wherein a ratio of a sum of the areas of each of the plurality of outlet ports to an area of the inner lumen is less than about 3;

1.

19. The device of claim 18, wherein the ratio of the sum of the areas of each of the plurality of outlet ports to the area of the inner lumen is less than about 2.5:

1.

20. The device of claim 18, wherein the ratio of the sum of the areas of each of the plurality of outlet ports to the area of the inner lumen is less than about 2:

1.

21. The device of claim 18, wherein the ratio of the sum of the areas of each of the plurality of outlet ports to the area of the inner lumen is less than about 1.3:

1.

22. The device of claim 18, wherein the ratio of the sum of the areas of each of the plurality of outlet ports to the area of the inner lumen is between about 0.5:

1 and about 2;

1.

23. An ablation device, comprising:

an elongate body having an inner lumen, the elongate body including a fluid delivery portion extending along a length thereof, the fluid delivery portion having a plurality of outlet ports configured to deliver fluid from the inner lumen to tissue surrounding the elongate body; and

an ablation element configured to heat tissue surrounding the elongate body;

wherein a cross-sectional area of the inner lumen through which fluid can flow decreases from a proximal end of the fluid delivery portion of the elongate body to a distal end thereof.

24. The device of claim 23, wherein a diameter of the inner lumen decreases from a proximal end to a distal end of the fluid delivery portion of the elongate body.

25. The device of claim 23, further comprising a flow diverter disposed within the fluid delivery portion of the inner lumen of the elongate body.

26. The device of claim 25, wherein the flow diverter has a substantially conical shape that increases in diameter from a proximal end thereof to a distal end thereof.

27. The device of claim 26, wherein the flow diverter includes any of at least one step to transition from a first diameter to a second diameter and at least one recess.

28. The device of claim 27, wherein any of the at least one step and at least one recess is aligned with one of the plurality of outlet ports formed in the elongate body.

29. The device of claim 25, further comprising a thermocouple positioned at a proximal end of the flow diverter.

30. The device of claim 25, further comprising a heating element positioned at a proximal end of the flow diverter and configured to heat fluid flowing within the inner lumen.