Multi-electrode catheter assemblies for renal neuromodulation and associated systems and methods

• US 8,888,773 B2
• Filed: 03/11/2013
• Issued: 11/18/2014
• Est. Priority Date: 05/11/2012
• Status: Active Grant

• Current Assignee: Medtronic Ardian Luxembourg SARL (Medtronic Plc)
• Original Assignee: Medtronic Ardian Luxembourg SARL (Medtronic Plc)
• Inventors: Chang, William W., Goshgarian, Justin, Mauch, Kevin Michael, Rivera, Leonila, Shin, Sukyoung, Tran, Don H.
• Primary Examiner(s): Wieland, Robert N
• Application Number:
  US13/793,647
• Publication Number:
  US 20130304061A1
• Time in Patent Office: 617 Days
• Field of Search: 606/41
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1206 Generators therefor
• 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 2018/00059 Material properties
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00404 Blood vessels other than those in or around the heart
• CPC Class Codes: A61B 2018/00434 Neural system
• CPC Class Codes: A61B 2018/00511 Kidney
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1435 Spiral
• CPC Class Codes: A61B 2018/1465 Deformable electrodes
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61M 2025/0915 having features for changing the stiffness
• CPC Class Codes: A61M 2205/6063 Optical identification systems
• CPC Class Codes: A61M 25/0102 Insertion or introduction using an inner stiffening member, e.g. stylet or push-rod
• CPC Class Codes: A61M 25/0108 using radio-opaque or ultrasound markers
• CPC Class Codes: A61M 25/09 Guide wires
• CPC Class Codes: A61N 1/36057 adapted for stimulating afferent nerves

Abstract

Catheter apparatuses, systems, and methods for achieving renal neuromodulation by intravascular access are disclosed herein. One aspect of the present technology, for example, is directed to a treatment device having a multi-electrode array configured to be delivered to a renal blood vessel. The array is selectively transformable between a delivery or low-profile state (e.g., a generally straight shape) and a deployed state (e.g., a radially expanded, generally spiral/helical shape). The multi-electrode array is sized and shaped so that the electrodes or energy delivery elements contact an interior wall of the renal blood vessel when the array is in the deployed (e.g., spiral/helical) state. The electrodes or energy delivery elements are configured for direct and/or indirect application of thermal and/or electrical energy to heat or otherwise electrically modulate neural fibers that contribute to renal function.

Claims

1. A catheter apparatus, comprising:

an elongated tubular shaft having a proximal portion and a distal portion; and

a therapeutic assembly disposed at the distal portion of the elongated shaft and adapted to be located at a target location within a renal artery of a human patient, the therapeutic assembly including a support structure comprising—

a control member comprising a pre-formed helical shape, wherein the control member is a tubular structure having a lumen therethrough and is composed of a nitinol multifilar stranded wire; and

a plurality of energy delivery elements carried by the support structure,

wherein the elongated tubular shaft and the therapeutic assembly together define therethrough a guide wire lumen configured to slidably receive a medical guide wire, and

wherein axial movement of the guide wire relative to the therapeutic assembly transforms the support structure between (a) a low-profile delivery configuration and (b) a deployed configuration tending to assume the pre-formed helical shape of the control member.

2. The catheter apparatus of claim 1 wherein the therapeutic assembly is configured to transform between the low-profile delivery configuration and the deployed configuration while at least a distal portion of the guide wire remains in the guide wire lumen of the therapeutic assembly.

3. The catheter apparatus of claim 2 wherein the support structure comprises a shape-recovery force sufficient to overcome a straightening force provided by a distal region of the guide wire to transform the therapeutic assembly to the deployed configuration when a distalmost tip of the guide wire is generally aligned with a distal tip of the therapeutic assembly.

4. The catheter apparatus of claim 1 wherein:

the support structure comprises a shape-recovery force insufficient to overcome a straightening force provided by a distal region of the guide wire when the guide wire is within the guide wire lumen of the therapeutic assembly; and

the therapeutic assembly is configured to transform to the deployed configuration when a distalmost portion of the guide wire is withdrawn though the guide wire lumen to a point proximal of the therapeutic assembly.

5. The catheter apparatus of claim 1 wherein a distal portion of the therapeutic assembly further comprises a flexible curved tip configured to provide an opening for the guide wire and, in the deployed configuration, to direct the guide wire away from a wall of the renal artery.

6. The catheter apparatus of claim 5 wherein the flexible curved tip is composed of polyether block amide copolymer.

7. The catheter apparatus of claim 5 wherein the flexible curved tip is composed of a thermoplastic polyether urethane material.

8. The catheter apparatus of claim 7 wherein the flexible curved tip is composed of about 5 to 30 weight percent of siloxane blended with the thermoplastic polyether urethane material.

9. The catheter apparatus of claim 1 wherein, in the deployed configuration, the energy delivery elements carried by the support structure are spaced apart from each other along a longitudinal axis of the renal artery and are configured to maintain apposition with a wall of the renal artery.

10. The catheter apparatus of claim 1 wherein the energy delivery elements comprise a series of band electrodes.

11. The catheter apparatus of claim 10 wherein at least one of the band electrodes comprises tapered end portions, and wherein the tapered end portions are configured to provide an obtuse angle between an outer surface of the support structure and an outer surface of the at least one band electrode.

12. The catheter apparatus of claim 1 wherein the therapeutic assembly comprises four energy delivery elements.

13. The catheter apparatus of claim 1, further comprising a retractable loading tool surrounding and restraining at least a longitudinal portion of the therapeutic assembly in the low-profile delivery configuration.

14. The catheter apparatus of claim 13 wherein the loading tool comprises a distal end portion having rounded edges.

15. A renal neuromodulation system for treatment of a human patient, the system comprising:

an elongate shaft having a proximal end and a distal end, wherein the distal end of the shaft is configured for intravascular delivery over a procedural guide wire to a renal artery of the patient;

a pre-shaped tubular spiral structure disposed at or proximate to the distal end of the elongate shaft, wherein the spiral structure is configured to transform between an unexpanded configuration and an expanded configuration that tends to assume the shape of the pre-shaped spiral structure, and wherein the spiral structure is composed, at least in part, of multifilar stranded nitinol wire; and

a plurality of electrodes associated with the spiral structure,

wherein the elongate shaft and the spiral structure together define a guide wire lumen therethrough, and wherein—

the guide wire lumen is configured to slidably receive the procedural guide wire to locate the spiral structure at a target treatment site within a renal blood vessel of the patient and to restrain the spiral structure in the unexpanded configuration, and wherein

proximal movement of the procedural guide wire through the guide wire lumen relative to the spiral structure such that a distal end portion of the guide wire is at least partially within the guide wire lumen transforms the spiral structure to the expanded configuration.

16. The system of claim 15 wherein the procedural guide wire comprises a distal portion having varying flexibility therealong, and further wherein at least a region of the distal portion of the guide wire is configured to remain within the portion of the guide wire lumen defined by the spiral structure when the spiral structure is in the expanded configuration.

17. The system of claim 15, further comprising a flexible tube covering and in intimate contact with the spiral structure.

18. The system of claim 17 wherein the plurality of electrodes are bonded to the flexible tube using an adhesive material.

19. The system of claim 15 wherein the plurality of electrodes are composed of gold.

20. The system of claim 15 wherein the plurality of electrodes are individually connectable to an energy source external to the patient, and wherein the energy source is capable of individually controlling the energy delivered to each electrode during therapy.

21. A method of performing renal neuromodulation, the method comprising:

intravascularly delivering a renal neuromodulation catheter in a low-profile delivery configuration over a guide wire to a target treatment site within a renal blood vessel of a human patient and at least proximate to a renal nerve of the patient, wherein the renal neuromodulation catheter comprises—

an elongated shaft; and

a multi-electrode array disposed at a distal portion of the shaft and composed, at least in part, of a tubular structure formed of multifilar nitinol wire;

withdrawing the guide wire in a proximal direction until the catheter transforms from the low-profile delivery configuration to a deployed configuration wherein the tubular structure has a radially expanded, generally spiral shape configured to contact the wall of the renal blood vessel and to allow blood to flow through the vessel; and

selectively delivering energy to one or more electrodes of the multi-electrode array to inhibit neural communication along the renal nerve.

22. The method of claim 21 wherein selectively delivering energy to one or more electrodes of the multi-electrode array comprises producing a plurality of lesions in a desired pattern along the renal blood vessel.

23. The method of claim 22 wherein the individual electrodes of the multi-electrode array are spaced sufficiently apart such that the lesions do not overlap.

24. The method of claim 21, further comprising attaching an external ground to an exterior of the patient, and wherein selectively delivering energy to one or more electrodes further comprises delivering an electric field in a monopolar fashion between each of the electrodes and the external ground.

25. The method of claim 21 wherein selectively delivering energy comprises selectively delivering an electric field in a bipolar fashion between the electrodes of the multi-electrode array.

26. The method of claim 21 wherein withdrawing the guide wire in a proximal direction until the therapeutic assembly transforms comprises only partially withdrawing the guide wire from the therapeutic assembly such that at least a portion of the guide wire remains in the therapeutic assembly after the therapeutic assembly transforms to the deployed configuration.

27. The method of claim 21 wherein withdrawing the guide wire in a proximal direction until the therapeutic assembly transforms comprises completely withdrawing the guide wire from the therapeutic assembly such that a distalmost portion of the guide wire is withdrawn to a point proximal of the therapeutic assembly.

28. The method of claim 21 wherein the target treatment site comprises a first target treatment site, and wherein the method further comprises:

advancing the guide wire in a distal direction after selectively delivering energy to the one or more electrodes of the multi-electrode array to transform the multi-electrode array from the deployed configuration back to the low-profile delivery configuration;

repositioning the catheter at a second target treatment site different than the first treatment site;

withdrawing the guide wire in a proximal direction to again transform the therapeutic assembly from the delivery configuration to the deployed configuration; and

selectively delivering energy to one or more electrodes of the multi-electrode array positioned at the second target treatment site.