Methods and apparatus for pulsed electric field neuromodulation via an intra-to-extravascular approach
Methods and apparatus are provided for pulsed electric field neuromodulation via an intra-to-extravascular approach, e.g., to effectuate irreversible electroporation or electrofusion, necrosis and/or inducement of apoptosis, alteration of gene expression, changes in cytokine upregulation and other conditions in target neural fibers. In some embodiments, the ITEV PEF system comprises an intravascular catheter having one or more electrodes configured for intra-to-extravascular placement across a wall of patient's vessel into proximity with target neural fibers. With the electrode(s) passing from an intravascular position to an extravascular position prior to delivery of the PEF, a magnitude of applied voltage or energy delivered via the electrode(s) and necessary to achieve desired neuromodulation may be reduced relative to an intravascular PEF system having one or more electrodes positioned solely intravascularly. The methods and apparatus of the present invention may, for example, be used to modulate one or more target neural fibers that contribute to renal function.
1. An apparatus for electric field neuromodulation, comprising:
an electric field generator;
an elongated element configured to be moved within a vascular structure of a patient;
at least one electrode electrically coupled to the field generator and having an intravascular portion associated with the elongated element and having an extravascular portion configured to be passed through a wall of the vascular structure; and
an actuator associated with the at least one electrode and being configured to move the electrode between a first position in which the extravascular portion of the electrode is within the vascular structure and a second position in which the extravascular portion of the electrode is located at an extravascular location for extravascular delivery of an electric field.
2. The apparatus of claim 1 , wherein the at least one electrode comprises at least one bipolar electrode pair having a first electrode and a second electrode, the bipolar electrode pair coupled to the field generator.
3. The apparatus of claim 2 , wherein the extravascular portion of the at least one electrode comprises the bipolar electrode pair.
4. The apparatus of claim 2 , wherein the intravascular portion of the at least one electrode comprises the first electrode of the bipolar electrode pair and the extravascular portion of the electrode comprises the second electrode of the bipolar electrode pair.
5. The apparatus of claim 2 , wherein the first electrode and the second electrode are longitudinally spaced apart from one another in the second position.
6. The apparatus of claim 1 , further comprising an external ground pad, wherein the extravascular portion of the at least one electrode is configured for monopolar extravascular delivery of the electric field.
7. The apparatus of claim 1 , wherein the actuator comprises a piercing element configured to pierce a wall of the vascular structure during movement of the extravascular portion of the at least one electrode between the first position and the second position.
8. The apparatus of claim 1 , wherein the extravascular portion of the at least one electrode comprises a piercing element configured to pierce a wall of the vascular structure during movement of the extravascular portion of the at least one electrode between the first position and the second position.
9. The apparatus of claim 1 further comprising infusate, wherein the apparatus is configured for extravascular infusion of the infusate.
10. The apparatus of claim 9 , wherein the infusate comprises neuromodulation-enhancing infusate or protective infusate.
11. The apparatus of claim 1 , wherein the actuator comprises an inflatable balloon.
12. The apparatus of claim 1 , wherein the actuator comprises an expandable cage or basket.
13. The apparatus of claim 1 , wherein the actuator comprises a transition element having a profile configured to direct the extravascular portion of the at least one electrode radially outward as the extravascular portion of the at least one electrode is moved between the first position and the second position.