Methods for catheter-based renal neuromodulation
Methods and apparatus are provided for monopolar neuromodulation, e.g., via a pulsed electric field. Such monopolar neuromodulation may effectuate irreversible electroporation or electrofusion, necrosis and/or inducement of apoptosis, alteration of gene expression, action potential attenuation or blockade, changes in cytokine up-regulation and other conditions in target neural fibers. In some embodiments, monopolar neuromodulation is applied to neural fibers that contribute to renal function. In some embodiments, such monopolar neuromodulation is performed bilaterally.
1. A method for catheter-based renal neuromodulation, the method comprising:
intravascularly positioning a catheter in a reduced profile delivery configuration within a renal artery of a human patient and adjacent to renal nerves that innervate a kidney of the patient;
transforming an expandable electrode at a distal region of the catheter from the reduced profile delivery configuration to a treatment configuration,
wherein the expandable electrode comprises a helical configuration, and wherein, in the treatment configuration, the expandable electrode is sized and shaped such that the helical electrode contacts an inner wall of the renal artery of the patient; and
delivering an electric field between the expandable electrode and a ground pad coupled to an exterior of the patient, thereby thermally inhibiting neural communication along the renal nerves,
wherein delivering the electric field and thermally inhibiting neural communication along the renal nerves results in a therapeutically beneficial reduction in blood pressure of the patient.
2. The method of claim 1 wherein the helical member comprises a self-expanding material.
3. The method of claim 1 wherein the helical member comprises nitinol.
4. The method of claim 1 wherein the catheter further comprises an expandable element proximal of the expandable electrode, and wherein the method further comprises expanding the expandable element into contact with the inner wall of the renal artery to hold the catheter at a desired treatment location within the renal artery before transforming the expandable electrode from the reduced profile delivery configuration to the treatment configuration.
5. The method of claim 4 wherein the expandable element comprises a balloon.
6. The method of claim 4 wherein expanding the expandable element into contact with the inner wall of the renal artery comprises occluding blood flow within the renal artery while the expandable element is in the expanded arrangement.
7. The method of claim 1 wherein thermally inhibiting neural communication along the renal nerves comprises blocking neural traffic to and/or from the kidney of the patient.
8. The method of claim 1 wherein delivering an electric field between the expandable electrode and a ground pad causes ablation of the renal nerves.
9. The method of claim 1 wherein delivering an electric field between the expandable electrode and a ground pad causes partial ablation of the renal nerves.
10. The method of claim 1 wherein intravascularly positioning a catheter in a reduced profile delivery configuration within a renal artery comprises positioning the catheter via a guide catheter.
11. The method of claim 1 wherein intravascularly positioning a catheter in a reduced profile delivery configuration within a renal artery comprises intravascularly positioning the catheter via a guide wire.
12. The method of claim 1 , further comprising monitoring a parameter of target tissue and/or non-target tissue within the patient before and during delivery of the electric field.
13. The method of claim 12 , further comprising altering delivery of the electric field in response to the monitored parameter.
14. The method of claim 12 wherein monitoring a parameter comprises monitoring temperature, power, and/or impedance.
15. The method of claim 1 wherein delivering the electric field and thermally inhibiting neural communication along the renal nerves comprises thermally altering the renal nerves in a manner that reduces neural traffic to and from a kidney of the patient.
16. A method for treating a hypertensive human patient, the method comprising:
attaching a ground pad to an exterior of the patient;
passing a renal denervation catheter comprising a monopolar electrode through vasculature of the patient to a renal blood vessel such that the monopolar electrode is located adjacent renal nerves of the patient,
wherein the monopolar electrode comprises an expandable helical electrode transformable between a low-profile delivery configuration and an expanded treatment configuration; and
ablating the renal nerves via electrical energy delivered in a monopolar fashion between the monopolar expandable helical electrode and the ground pad,
wherein ablating the renal nerves of the patient attenuates neural communication along the renal nerves and thereby results in a therapeutically beneficial reduction in blood pressure of the patient.
17. The method of claim 16 wherein ablating the renal nerves via electrical energy comprises ablating the renal nerves via radio frequency (RF) energy delivered via the monopolar expandable helical electrode.
18. The method of claim 16 wherein ablating the renal nerves via electrical energy delivered in a monopolar fashion comprises reducing efferent neural activity across the renal nerves.
19. The method of claim 16 wherein ablating the renal nerves via electrical energy delivered in a monopolar fashion comprises reducing afferent neural activity across the renal nerves.
20. The method of claim 16 wherein ablating the renal nerves via electrical energy delivered in a monopolar fashion comprises at least partially denervating a kidney of the patient.
21. The method of claim 16 , further comprising removing the renal denervation catheter from the patient after ablating the renal nerves.
22. The method of claim 16 wherein the renal denervation catheter further comprises one or more monitoring elements located adjacent the monopolar electrode and configured to monitor temperature and/or impedance, and wherein the method further comprises controlling ablating the renal nerves based, at least in part, on the monitored temperature and/or impedance.
23. A method, comprising:
positioning a renal denervation catheter in a reduced profile delivery configuration within a renal artery of a human patient and adjacent to neural fibers that innervate a kidney of the patient;
transforming an expandable electrode at a distal region of the renal denervation catheter from the reduced profile delivery configuration to a treatment configuration,
wherein the expandable electrode comprises a spiral configuration, and wherein, in the treatment configuration, the expandable electrode is sized and shaped such that the spiral electrode contacts an inner wall of the renal artery of the patient; and
delivering an electric field between the expandable electrode and a ground pad coupled to an exterior of the patient, thereby thermally inhibiting neural communication along the neural fibers,
wherein delivering the electric field and thermally inhibiting neural communication along the neural fibers results in a therapeutically beneficial reduction in sympathetic overactivity of the patient.