Patent Application
20140088585
This disclosure generally relates to percutaneous and intravascular devices for nerve modulation and/or ablation.
Certain treatments may require the temporary or permanent interruption or modification of select nerve function. One example treatment is renal nerve ablation which is sometimes used to treat conditions related to hypertension and/or congestive heart failure. The kidneys produce a sympathetic response to congestive heart failure, which, among other effects, increases the undesired retention of water and/or sodium. Ablating some of the nerves running to the kidneys may reduce or eliminate this sympathetic function, which may provide a corresponding reduction in the associated undesired symptoms.
Many bodily tissues such as nerves, including renal nerves, brain tissue, cardiac tissue and the tissue of other body organs are in close proximity to blood vessels or other body cavities and, thus, can be accessed percutaneously or intravascularly through adjacent blood vessels. In some instances, it may be desirable to ablate perivascular nerves using a radio frequency (RF) electrode. In other instances, the perivascular nerves may be ablated by other means including application of thermal, ultrasonic, laser, microwave, and other related energy sources to the vessel wall.
Because the nerves are hard to visualize, treatment methods employing such energy sources have tended to apply the energy as a generally circumferential ring to ensure that the nerves are modulated. However, such a treatment may result in thermal injury to the vessel wall near the electrode and other undesirable side effects such as, but not limited to, blood damage, clotting, weakened vessel wall, and/or protein fouling of the electrode.
Some illustrative embodiments pertain to an intravascular catheter for modulating and/or ablating renal nerves which includes an elongated catheter body having an ablation region. The ablation region can include a flexible portion having a plurality of slots formed therein defining at least one spine extending along a length of the flexible portion and a plurality of ribs extending away from the spine such that the flexible portion is configured to transition from a first configuration suitable for delivery of the catheter to a second configuration having at least one bend, curve or turn suitable for ablating renal nerves. Additionally, the catheter can include at least one conductor extending within the elongated catheter body; two or more ablation elements coupled to the conductor extending within the elongated catheter body and located along the ablation region; and an actuation member coupled to the ablation region for transitioning the ablation region from the first configuration to the second configuration. In some embodiments, the two or more ablation elements are electrodes, wherein each electrode is configured to deliver sufficient RF energy so as to ablate renal nerves.
Some illustrative embodiments pertain to a method of ablating target nerve tissue from a location within a body vessel which includes delivering an intravascular catheter to a location within the body vessel adjacent the target nerve tissue. The catheter can include: an elongated catheter body having an ablation region configured to transition from a first configuration suitable for delivery of the catheter to a second configuration for ablating target tissue in a circumferential pattern along a length of the body vessel; at least one electrical conductor extending within the elongated catheter body; and a plurality of ablation elements located along the ablation region and coupled to the conductor extending within the elongated catheter body. Additionally, the methods can include transitioning the ablation region from the first configuration to the second configuration and delivering sufficient energy via the ablation elements positioned along the ablation region, wherein the target renal nerve tissue is ablated in a substantially circumferential pattern along the length of the body vessel.
The preceding summary is provided to facilitate an understanding of some of the innovative features unique to the present disclosure and is not intended to be a full description. A full appreciation of the disclosure can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
The disclosure may be more completely understood in consideration of the following detailed description of various illustrative embodiments of the disclosure in connection with the accompanying drawings, in which:
While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.
For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.
It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with one embodiment, it should be understood that such feature, structure, or characteristic may also be used in connection with other embodiments whether or not explicitly described unless clearly stated to the contrary.
While the devices and methods described herein are discussed relative to renal nerve modulation through a blood vessel wall, it is contemplated that the devices and methods may be used in other applications where nerve modulation and/or ablation are desired. The term modulation refers to ablation and other techniques that may alter the function of affected nerves and other tissue such as brain tissue or cardiac tissue.
According to various illustrative embodiments, system 6 includes an intravascular, renal ablation catheter 18 and one or more conductor(s) 22 for providing power to catheter 18. A proximal end of conductor(s) 22 is connected to a control and power element 26, which supplies necessary electrical energy to activate one or more electrodes disposed along an ablation region at or near a distal end of catheter 18. When suitably activated, the electrodes are capable of ablating adjacent tissue. In some cases, a temperature sensing wire such as, for example, a thermocouple may also be used at each electrode. The terms electrode and electrodes may be considered to be equivalent to elements capable of ablating adjacent tissue in the disclosure which follows. In some instances, system 6 can include return electrode patches 28 that may be applied to the patient's legs or at another conventional location on the patient's body to complete the circuit.
In some embodiments, control and power element 26 includes monitoring elements to monitor parameters such as power, temperature, voltage, amperage, impedance, pulse size and/or shape and other suitable parameters. The monitoring elements may include sensors mounted along catheter 18, as well as suitable controls for performing a desired procedure. In some embodiments, control and power element 26 control the one or more electrodes located in an ablation region of the catheter 18, as will be described in more detail below. In some embodiments, the one or more electrodes include one or more radio frequency (RF) electrodes. The electrode(s) may be configured to operate at a frequency of approximately 460 kHz. It is contemplated that any desired frequency in the RF range may be used, for example, from 450-500 kHz. It is further contemplated that additional and/or other ablation devices may be used as desired, for example, but not limited to resistance heating, ultrasound, microwave, and laser devices, and these devices may require that power be supplied by the power element 26 in a different form.
Catheter 30 also includes an ablation region 46 located at or near a distal region 52 of the catheter body 34. In some cases, the ablation region 46 may include the distal end 42 of the catheter body 34, but this is not required. As shown in
According to various embodiments, the ablation region 46 of catheter 30 is flexible such that the ablation region 46 including the one or more ablation elements 56 may be more easily positioned near the target tissue such that catheter 30 may be capable of ablating the target tissue while minimizing damage to non-target tissue. For example, the ablation region 46 may be sufficiently flexible such that it is configured to transition from a first configuration suitable for delivery of catheter 30 to a position near the target tissue to a second configuration suitable for ablating the target tissue such as, for example, renal nerve tissue. In the first configuration, the ablation region 46 is substantially straight such that catheter 30 including the ablation region 46 may be delivered to a location in a body lumen or vessel adjacent the target tissue. In the second configuration, the ablation region 46 has a two-dimensional or three-dimensional shape including at least one bend, turn, or curve such that at least a portion of the ablation region 46 may be positioned in closer proximity to the target tissue for ablation.
In some cases, as shown, the tubular member 70 includes a plurality of cuts, slits, and/or slots 78 formed therein (collectively referred to herein as “slots”), thereby increasing the overall flexibility of the flexible portion 66 of each of the ablation regions 46a-46f. Slots 78 may be formed by methods such as micro-machining, saw-cutting (e.g., using a diamond grit embedded semiconductor dicing blade), electrical discharge machining, grinding, milling, casting, molding, chemically etching or treating, or other known methods, and the like. In such embodiments, the structure of the tubular member 70 is formed by cutting and/or removing portions of the tube to form slots 78. Some examples of appropriate micromachining methods and other cutting methods, and structures for tubular members including slots and medical devices including tubular members are disclosed in U.S. Pat. Publication Nos. 2003/0069522 and 2004/0181174-A2; and U.S. Pat. Nos. 6,766,720; and 6,579,246, the entire disclosures of which are herein incorporated by reference for all purposes. Some examples of etching processes are described in U.S. Pat. No. 5,106,455, the entire disclosure of which is herein incorporated by reference for all purposes. In still some embodiments, slots 78 are formed in tubular member 70 using a laser cutting process.
Various arrangements and configurations are contemplated for slots 78 formed in the tubular member 70. For example, in some embodiments, at least some, if not all of slots 78 may be disposed at the same or a similar angle with respect to the longitudinal axis x of the tubular member 70. As shown in the illustrative embodiments of
Slots 78 are provided to enhance the flexibility of the tubular member 70 while still allowing for suitable torque transmission characteristics. Slots 78 can be formed such that one or more rings and/or tube segments interconnected by one or more segments and/or beams that are formed in the tubular member 70. Such tube segments and/or beams may include portions of the tubular member 70 that remain after slots 78 are formed in the tubular member 70. Such an interconnected structure may act to maintain a relatively high degree of torsional stiffness, while maintaining a desired level of lateral flexibility. In some embodiments, some adjacent slots 78 can be formed such that they include portions that overlap with each other about the circumference of the tubular member 70. In other embodiments, some adjacent slots 78 can be disposed such that they do not necessarily overlap with each other, but are disposed in a pattern that provides the desired degree of lateral flexibility.
Additionally, slots 78 may be arranged along the length of, or about the circumference of, the tubular member 70 to achieve desired properties. For example, adjacent slots 78 or groups of slots 78 can be arranged in a symmetrical pattern, such as being disposed essentially equally on opposite sides about the circumference of the tubular member 70, or can be rotated by an angle relative to each other about the axis of the tubular member 70. Additionally, adjacent slots 78, or groups of slots 78, may be equally spaced along the length of the tubular member 70, or can be arranged in an increasing or decreasing density pattern, or can be arranged in a non-symmetric or irregular pattern. Other characteristics, such as slot size, slot shape, and/or slot angle with respect to the longitudinal axis of tubular member 70, can also be varied along the length of the tubular member 70 in order to vary the flexibility or other properties.
In some embodiments, slots 78 may be formed in groups of two, three, four, five, or more slots 78, which may be located at substantially the same location along the axis of the tubular member 70. Within the groups of slots 78, there may be included slots 78 that are equal in size such that they may span the same circumferential distance around the tubular member 70. Additionally, in some embodiments, at least some slots 78 in a group may be unequal in size such that they span a different circumferential distance around tubular member 70. Longitudinally adjacent groups of slots 78 may have the same or different configurations. For example, some embodiments of the tubular member 70 include slots 78 that are equal in size in a first group and then unequally sized in an adjacent group.
In some cases, as shown in the illustrative embodiments of
According to some embodiments, as shown in
As discussed herein, each of the ablation regions 46a-46f are sufficiently flexible such that they are capable of transitioning from a first configuration suitable for delivery of a catheter (e.g. catheter 30) to a location within a body lumen or vessel adjacent to the target nerve tissue to a second configuration suitable for ablating target tissue from the location within the adjacent body lumen or vessel using the multiple electrodes 56. The electrodes 56 are distributed along a length of each of the ablation regions 46a-46e such that when each of the ablation regions 46a-46e are in a second configuration, the electrodes 56 may achieve complete circumferential coverage of the body lumen or blood vessel while spaced apart longitudinally along its length. As such, when the ablation regions 46a-46e are in the second configuration, the electrodes 56 may be capable of ablating the nerves at multiple locations along the length and around a circumference of the body lumen without the need for repositioning the catheter (e.g. catheter 30) in the body lumen or vessel adjacent the target tissue.
In other embodiments, a single electrode 56 may be located along the ablation region 46f of the catheter body 34. In one embodiment, as shown in
Referring now back to
toward the user). In one embodiment, the ablation region 46 can be transitioned back from the second configuration to the first configuration by pushing or releasing the pull wire 84 in a distal direction.
In another embodiment, as shown in
In the second configuration, as shown in
After ablation has occurred, the ablation region 246 is transitioned from the second configuration to the first configuration for repositioning of the catheter 30 within the vessel 250 and/or withdrawal. It will be generally understood that the ablation procedure, as described herein, may be performed under visualization (e.g. fluoroscopy) using techniques known to those of skill in the art.
Although various embodiments of the disclosure are specifically illustrated and described herein, it will be appreciated that modifications and variations of the present disclosure are covered by the above teachings without departing from the spirit and intended scope of the disclosure.
This Application claims the benefit under 35 USC §119 of U.S. Provisional Application No. 61/705,925, filed on Sep. 26, 2012, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61705925 | Sep 2012 | US |
