Catheter apparatuses having expandable balloons for renal neuromodulation and associated systems and methods
Methods and apparatus are provided for treating contrast nephropathy, e.g., via a pulsed electric field, via a stimulation electric field, via localized drug delivery, via high frequency ultrasound, via thermal techniques, etc. Such 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, neuromodulation is applied to neural fibers that contribute to renal function. In some embodiments, such neuromodulation is performed in a bilateral fashion. Bilateral renal neuromodulation may provide enhanced therapeutic effect in some patients as compared to renal neuromodulation performed unilaterally, i.e., as compared to renal neuromodulation performed on neural tissue innervating a single kidney.
1. A method for catheter-based renal neuromodulation, the method comprising:
positioning a first catheter having a first therapeutic element in a low profile delivery configuration within a first renal blood vessel of a human patient and proximate to neural fibers innervating a first kidney of the patient,
wherein the first therapeutic element comprises a first expandable balloon sized and shaped for the first renal blood vessel, and wherein the first expandable balloon comprises a plurality of first electrodes arranged thereon,
transforming the first therapeutic element from the delivery configuration to a treatment configuration such that the first electrodes on the first expandable balloon are in contact with an inner wall of the first renal blood vessel;
inhibiting neural communication along the neural fibers innervating the first kidney via radio frequency (RF) energy from the first electrodes;
positioning a second catheter having a second therapeutic element in a low profile delivery configuration within a second renal blood vessel of the patient and proximate to neural fibers innervating a second kidney of the patient,
wherein the second therapeutic element comprises a second expandable balloon sized and shaped for the second renal blood vessel, and wherein the second balloon comprises a plurality of second electrodes arranged thereon;
transforming the second therapeutic element from the delivery configuration to a treatment configuration such that the plurality of second electrodes on the second expandable balloon are in contact with an inner wall of the second renal blood vessel; and
inhibiting neural communication along the neural fibers innervating the second kidney via RF energy from the second electrodes.
2. The method of claim 1 wherein the first renal blood vessel has a different diameter than the second renal blood vessel, and wherein the first balloon comprises a different size than the second balloon.
3. The method of claim 1 wherein the first renal blood vessel has the same or approximately the same diameter as the second renal blood vessel, and wherein the first balloon is the same size as the second balloon.
4. The method of claim 1 , further comprising removing the first catheter from the first renal blood vessel of the patient before positioning the second catheter within the second renal blood vessel of the patient.
5. The method of claim 1 wherein positioning the first catheter within the first renal blood vessel of the patient and positioning the second catheter within the second renal blood vessel of the patient occur simultaneously.
6. The method of claim 1 wherein:
positioning the first catheter within the first renal blood vessel of the patient comprises intravascularly delivering the first catheter to the first renal blood vessel over a first guidewire; and
positioning the second catheter within the second renal blood vessel of the patient comprises intravascularly delivering the second catheter to the second renal blood vessel over a second guidewire.
7. The method of claim 1 wherein:
inhibiting neural communication along the neural fibers innervating the first kidney comprises ablating the neural fibers innervating the first kidney; and
inhibiting neural communication along the neural fibers innervating the second kidney comprises ablating the neural fibers innervating the second kidney.
8. The method of claim 1 wherein:
inhibiting neural communication along the neural fibers innervating the first kidney comprises denervating the first kidney of the patient; and
inhibiting neural communication along the neural fibers innervating the second kidney comprises denervating the second kidney of the patient.
9. The method of claim 1 wherein:
inhibiting neural communication along the neural fibers innervating the first kidney comprises denervating the first kidney of the patient; and
inhibiting neural communication along the neural fibers innervating the second kidney comprises denervating the second kidney of the patient.
10. The method of claim 1 wherein:
inhibiting neural communication along the neural fibers innervating the first kidney comprises reducing renal sympathetic nerve activity of the first kidney; and
inhibiting neural communication along the neural fibers innervating the second kidney comprises reducing renal sympathetic nerve activity of the second kidney.
11. The method of claim 1 wherein:
transforming the first therapeutic element from the delivery configuration to the treatment configuration further comprises occluding blood flow in the first renal blood vessel via the first expandable balloon; and
transforming the second therapeutic element from the delivery configuration to the treatment configuration further comprises occluding blood flow in the second renal blood vessel via the second expandable balloon.
12. The method of claim 1 wherein the first electrodes comprise first bipolar RF electrodes, and wherein the second electrodes comprise second bipolar RF electrodes.
13. The method of claim 1 wherein the first electrodes and second electrodes comprise monopolar electrodes, and wherein
inhibiting neural communication via RF energy from the first electrodes comprises delivering RF energy in a monopolar fashion between the first electrodes and a ground electrode such that the resulting energy field attenuates neural communication along the neural fibers innervating the first kidney; and
inhibiting neural communication via RF energy from the second electrodes comprises delivering RF energy in a monopolar fashion between the second electrodes and the ground electrode such that the resulting energy field attenuates neural communication along the neural fibers innervating the second kidney.
14. A method for catheter-based renal denervation, the method comprising:
intravascularly positioning a first catheter having an expandable distal first balloon within a first renal artery of a human patient;
at least partially ablating nerves along the first renal artery via electric energy from first bipolar RF electrodes arranged about a surface of the first balloon;
intravascularly positioning a second catheter having an expandable distal second balloon within a second renal artery of the patient, wherein the second balloon is different from the first balloon; and
at least partially ablating nerves along the second renal artery via electric energy from second bipolar RF electrodes arranged about a surface of the second balloon.
15. The method of claim 14 wherein the individual first bipolar RF electrodes comprise at least one pair of first bipolar contacts, and wherein the individual second bipolar RF electrodes comprise at least one pair of second bipolar contacts.
16. The method of claim 14 wherein at least partially ablating the nerves along the first renal artery and the nerves along the second renal artery results in a therapeutically beneficial reduction in blood pressure in the patient.
17. The method of claim 14 wherein at least partially ablating the nerves along the first renal artery and the nerves along the second renal artery results in a therapeutically beneficial reduction in central sympathetic overactivity of the patient.
18. The method of claim 14 , further comprising:
monitoring contact between the first bipolar RF electrodes and a wall of the first renal artery; and
monitoring contact between the second bipolar RF electrodes and a wall of the second renal artery.
19. The method of claim 18 wherein monitoring contact between the first and second bipolar RF electrodes and the walls of the first and second renal arteries, respectitvely, comprises monitoring impedance and/or temperature.
20. The method of claim 18 , further comprising adjusting a treatment parameter in response to the monitoring.