Patent Publication Number: US-2012035691-A1

Title: System and method for securing a lead in a vessel

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/371,057, filed on Aug. 5, 2010, entitled “System and Method for Securing a Lead in a Vessel,” which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a system and a method for securing a medical electrical lead within a vessel so that neurostimulation can be delivered to an adjacent nerve. More particularly, the present invention relates to a two-part system and corresponding method for securing a neurostimlation lead within a patient&#39;s internal jugular vein at a location adjacent a target region of the vagus nerve within the carotid sheath so that neurostimulation can be delivered to a target region of the vagus nerve. 
     BACKGROUND 
     The use of nerve stimulation for treating and controlling a variety of medical, psychiatric, and neurological disorders has seen significant growth over the last several decades, including for treatment of heart conditions, epilepsy, obesity, and breathing disorders, among others. For example, modulation of the autonomic balance with neural stimulation has been shown to be possible and have positive clinical benefits, such as protecting the myocardium from further remodeling and predisposition to fatal arrhythmias following a myocardial infarction (MI). 
     SUMMARY 
     Example 1 is a lead system for stimulating a region of a vagus nerve from a location within an internal jugular vein, the system comprising: a medical electrical lead comprising a lead body extending from a proximal end to a distal end, a conductor extending within the lead body from the proximal end in a direction towards the distal end, and an electrode region having a first length along the lead body comprising at least one electrode located on the lead body and operatively coupled to the conductor, the electrode adapted to transvasculary deliver an electrical stimulation pulse to the target region of the vagus nerve from a location within the internal jugular vein; and a stent-like fixation member independently deployable of the lead, the stent-like fixation member having a second length extending in a direction along a longitudinal axis of the stent-like fixation member that is greater than the first length of the electrode region of the lead, the stent-like fixation member adapted to transition from a collapsed configuration for delivery to a location within the internal jugular vein to an expanded configuration, wherein in the expanded configuration, the fixation member is adapted to contact and engage the electrode region of the medical electrical lead such that the fixation member urges the electrode region including the electrode into a vessel wall adjacent the target region of the vagus nerve. 
     In Example 2, the system according to Example 1, wherein the elongated, stent-like fixation member includes a channel extending from a first end to a second end of the fixation member, the channel sized to receive and engage a portion of the lead body therein. 
     In Example 3, the system according to Example 2, wherein the channel has an inner diameter corresponding to the outer diameter of the lead body received therein. 
     In Example 4, the system according to Examples 2 or 3, wherein the channel is adapted to expand to an increased inner diameter so as to receive and engage the lead body therein. 
     In Example 5, the system according to any one Examples 1-4, wherein the stent-like fixation member is sufficiently resilient such that it wraps around and engages an outer surface of the lead body forming a channel around the lead body. 
     In Example 6, the system according to any one of Examples 1-5, wherein the elongated, stent-like fixation member includes a channel sized to receive and engage the lead body therein extending from a proximal end to a distal end of the fixation member and a tether coupled to the distal end of the channel and extending away from the stent-like fixation member in a proximal direction and the lead body further includes a lumen extending from the proximal end to the distal end of the lead body, wherein the lead body lumen facilitates delivery of the lead over the tether to be received channel of the stent-like fixation member. 
     In Example 7, the system according to any one of Examples 1-6, wherein the stent-like fixation member further includes a tether coupled to and extending in a proximal direction away from the stent-like fixation member and the lead body further includes a guide feature coupled to an outer surface of lead body such that the lead body is adapted to track alongside the tether. 
     In Example 8, the system according to any one of Examples 1-7, wherein the stent like fixation member further includes a tether coupled to and extending in a proximal direction away from the stent-like fixation member, the tether including or being formed from one or more conductors extending within the tether from a proximal end to a distal end of the tether and one or more electrodes located on an outer surface of the stent-like fixation member and operatively coupled to the one or more conductors extending within the tether. 
     In Example 9, the system according to any one of Examples 1-8, wherein the stent-like fixation member is balloon expandable. 
     In Example 10, the system according to any one of Examples 1-9, wherein the stent-like fixation member self-expanding. 
     In Example 11, the system according to any one of Examples 1-10, wherein the stent-like fixation member includes an insulative polymer coating or sheath. 
     In Example 12, the system according to any one of Examples 1-11, wherein the electrode region of the lead includes a pre-formed spiral region defining a lumen. 
     In Example 13, the system according to any one of Examples 1-12, wherein the electrode region of the lead includes a two-dimensional shape. 
     In Example 14, the system according to any one of Examples 1-13, wherein the stent-like member further includes a tether coupled to and extending away from a proximal end of the stent-like member and wherein the lead body further includes a lumen extending from the proximal end to the distal end of the lead body, wherein the lead body lumen facilitates delivery of the lead over the tether. 
     In Example 15, the system according to any one of Examples 1-14, wherein the lead body further includes one or more projections adapted to engage an outer surface of the stent-like fixation member. 
     Example 16 is a lead system for stimulating a region of a vagus nerve from a location within an internal jugular vein, the system comprising: a medical electrical lead comprising a lead body extending from a proximal end to a distal end, a lumen extending within the lead body from the proximal end to the distal end, a conductor extending within the lead body from the proximal end in a direction towards the distal end, and an electrode region comprising at least one electrode located on the lead body and operatively coupled to the conductor, the electrode adapted to transvasculary deliver an electrical stimulation pulse to the target region of the vagus nerve from a location within the internal jugular vein; and a stent-like fixation member independently deployable of the lead, the stent-like fixation member comprising a concave channel extending from a proximal end to a distal end of the stent-like member and sized and shaped to receive the lead body therein, the stent-like fixation member adapted to transition from a collapsed configuration for delivery to a location within the internal jugular vein to an expanded configuration, wherein in the expanded configuration, the stent-like fixation member urges the electrode region including the at least one electrode into a vessel wall adjacent the target region of the vagus nerve. 
     In Example 17, the system according to Example 16, wherein the stent-like fixation has a length when expanded extending in a direction along a longitudinal axis of the stent-like fixation member that is greater than a length of the electrode region of the lead. 
     In Example 18, the system according to Example 16 or 17, wherein the stent-like fixation member further includes a tether coupled to the distal end of the stent-like fixation member and extending away from the stent-like member in a proximal direction, wherein the lead body lumen facilitates delivery of the lead over the tether to be received in the channel of the stent-like fixation member. 
     In Example 19, the system according to any one of Examples 16-18, wherein the stent-like fixation member further includes a tether coupled to the distal end of the stent-like fixation member and extending in a proximal direction away from the stent-like fixation member and the lead body further includes a guide feature coupled to an outer surface of lead body such that the lead body is adapted to track alongside the tether to be received in the channel of the stent-like fixation member. 
     In Example 20, the system according to any one of Examples 16-19, wherein the stent like fixation member further includes a tether coupled to and extending in a proximal direction away from the stent-like fixation member, the tether comprising one or more conductors extending within the tether from a proximal end to a distal end of the tether and one or more electrodes located on an outer surface of the stent-like fixation member and operatively coupled to the one or more conductors extending within the tether. 
     In Example 21, the system according to any one of Examples 16-20, wherein the stent-like member further includes an insulative coating or sheath. 
     Example 22 is a method for securing and stabilizing a medical electrical lead in a patient&#39;s internal jugular vein at a location adjacent a region of a vagus nerve to be stimulated located within the patient&#39;s carotid sheath, the method comprising: advancing a medical electrical lead into a patient&#39;s internal jugular vein to a location adjacent the region of the vagus nerve to be stimulated, the lead comprising a lead body extending from a proximal end to a distal end, a conductor extending within the lead body from the proximal end in a direction towards the distal end, and an electrode region comprising at least one electrode located on the lead body and operatively coupled to the conductor, the electrode adapted to transvasculary deliver an electrical stimulation pulse to the target region of the vagus nerve from a location within the internal jugular vein; advancing an independent stent-like fixation member retained in a collapsed configuration within a delivery catheter to a location adjacent the electrode region of the medical electrical lead; and deploying the independent stent-like fixation member from the delivery catheter such that the stent-like fixation member transitions from the collapsed configuration to an expanded configuration, wherein in the expanded configuration, the stent-like fixation member contacts and engages the electrode region of the lead and urges the electrode region including the at least one electrode into a vessel wall adjacent the region of the vagus nerve to be stimulated. 
     In Example 23, the method according to Example 22, wherein the lead body further includes a three-dimensional spiral shape defining a lumen and the stent-like fixation member is advanced into the lumen of the three-dimensional spiral shape. 
     In Example 24, the method according to Examples 22 or 23, further comprising repositioning the electrode region by rotating the stent-like fixation member after the stent is partially expanded. 
     In Example 25, the method according to any one of Examples 22-24, further comprising partially deploying the stent-like fixation member from the delivery catheter until the stent-like fixation member contacts and engages the electrode region and then, rotating the partially deployed stent-like fixation member to reposition the electrode region within the internal jugular vein. 
     Example 26 is a method for securing and stabilizing a medical electrical lead in a patient&#39;s internal jugular vein at a location adjacent a region of a vagus nerve to be stimulated located within the patient&#39;s carotid sheath, the method comprising: advancing a stent-like fixation member retained in a collapsed configuration within a delivery catheter to a location within the internal jugular vein adjacent the region of the vagus nerve to be stimulated, the stent-like fixation member comprising a concave channel sized and shaped to receive the lead therein extending from a proximal end to a distal end of the stent-like member and a tether coupled to the distal end of the stent-like member and extending in a proximal direction away from the stent-like fixation member; deploying the stent-like fixation member from the delivery catheter such that the stent-like fixation member transitions from the collapsed configuration to an expanded configuration and anchors in the vein; and advancing a medical electrical lead including a lumen over the tether such that a portion of the medical electrical lead comprising at least one electrode is received and retained within the concave channel of the stent-like fixation member. 
     In Example 27, a method according to Example 26, wherein the stent-like fixation member further includes one or more electrodes located on an outer surface of the stent-like fixation member and operatively coupled to one or more conductors extending within the tether and wherein the method further includes the steps of partially deploying the stent-like fixation member and acutely stimulating the vagus nerve using the one or more electrodes to identify an optimal location for delivering electrical stimulus therapy to the vagus nerve. 
     Example 28 is a method for securing and stabilizing a medical electrical lead in a patient&#39;s internal jugular vein at a location adjacent a region of a vagus nerve to be stimulated located within the patient&#39;s carotid sheath, the method comprising: advancing a stent-like fixation member retained in a collapsed configuration within a delivery catheter to a location within the internal jugular vein adjacent the region of the vagus nerve to be stimulated, the stent-like fixation member comprising a concave channel sized and shaped to receive the lead therein extending from a proximal end to a distal end of the stent-like member and a tether coupled to the distal end of the stent-like member and extending in a proximal direction away from the stent-like fixation member; deploying the stent-like fixation member from the delivery catheter such that the stent-like fixation member transitions from the collapsed configuration to an expanded configuration; and advancing a medical electrical lead including a guide feature alongside the tether such that a portion of the medical electrical lead comprising at least one electrode is received and retained within the concave channel of the stent-like fixation member. 
     In Example 29, the method according to Example 28, wherein the stent-like fixation member further includes one or more electrodes located on an outer surface of the stent-like fixation member and operatively coupled to one or more conductors extending within the tether and wherein the method further comprises the steps of partially deploying the stent-like fixation member and acutely stimulating the vagus nerve using the one or more electrodes, rotating the stent to identify an optimal location for delivering electrical stimulus therapy to the vagus nerve and advancing the lead into the channel once the proper orientation is obtained. 
     While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a system for stimulating a region of a patient&#39;s vagus nerve located within the carotid sheath according to an embodiment of the present invention. 
         FIG. 2  is a schematic view of an electrode according to an embodiment of the present invention. 
         FIGS. 3A and 3B  are schematic views of a fixation member for use with the system as shown in  FIG. 1  according to various embodiments of the present invention. 
         FIGS. 4A-4C  are close-up, schematic views of the system shown in  FIG. 1  according to various embodiments of the present invention. 
         FIG. 5A  is a close-up, schematic view of a system according to an embodiment of the present invention prior to implantation of the lead. 
         FIG. 5B  is a close-up, schematic view of the system shown in  FIG. 5A  according to an embodiment of the present invention after implantation of the lead. 
         FIG. 6  is a close-up, schematic view of a system for stimulating a region of a patient&#39;s vagus nerve located within the carotid sheath according to another embodiment of the present invention. 
         FIGS. 7A-7B  are close-up, schematic view of a system according to an embodiment of the present invention prior to implantation and during delivery of a lead. 
         FIG. 7C  is a close-up, schematic view of the system shown in  FIGS. 7A and 7B  according to an embodiment of the present invention after implantation of the lead. 
         FIG. 8A  is a close-up, schematic view of a system according to yet another embodiment of the present invention prior to implantation of a lead. 
         FIG. 8B  is a close-up schematic view of the system shown in  FIG. 8A  according to an embodiment of the present invention after implantation of the lead. 
         FIG. 9  is a block diagram of a method according to an embodiment of the present invention. 
         FIG. 10  is a block diagram of a method according to another embodiment of the present invention. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
       FIG. 1  shows a system  2  for stimulating a region of a patient&#39;s vagus nerve  6  located within the carotid sheath  10 . The carotid sheath  10  is a tube-shaped fascia wrapping the common carotid artery (not shown), the internal jugular vein (IJV)  14 , and the vagus nerve  6 . The system  2  includes a neurostimulation lead  18  coupled to an implantable medical device (IMD)  22  such as, for example, a pulse generator and an independent fixation member  26  that is provided separate from the lead  18 . According to various embodiments, the independent fixation member  26  is delivered to the implant site independently and separate from the lead  18 . The lead  18  is secured within the internal jugular vein  14  at a target location adjacent a region of the vagus nerve  6  to be stimulated using the fixation member  26 . 
     The neurostimulation lead  18  includes an elongated, insulative lead body  34  and extending from a proximal end  38  to a distal end  42 . The lead  18  is coupled to the IMD  22  via a connector (not shown) located at the proximal end  38  of its lead body  34 . The lead body  34  is flexible and, in some embodiments, may have a circular cross-section. Alternatively, in other embodiments the lead body  34  (or portions thereof) may have non-circular (e.g., elliptical) cross-sectional shapes. In some embodiments, the lead body  34  can include multiple lumens. For example, in one embodiment, the lead body  34  can include one or more guide lumens to receive a guide member such as a guidewire or stylet or to facilitate over-the-wire delivery of the lead  18  to the desired implantation site. 
     According to various embodiments, the neurostimulation lead  18  can include a plurality of conductors including individual wires, coils, or cables extending within the lead body  34  from the proximal end  38  in a direction towards the distal end  42  of the lead body  34 . The conductors can be insulated with an insulator such as silicone, polyurethane, ethylene tetrafluoroethylene, or another biocompatible, insulative polymer. In one exemplary embodiment, the conductors have a co-radial design. In this embodiment, each individual conductor is separately insulated and then wound together in parallel to form a single coil. In another exemplary embodiment, the conductors have a co-axial, non-co-radial configuration. In still other embodiments, one or more of the conductors is a stranded cable conductor each routed through one of the aforementioned lumens in the lead body  34 . In short, any conductor configuration can be employed in the lead according to the various embodiments of the present invention. 
     The lead  18  includes at least one electrode  50  located on an electrode region  54  of the lead body  34 . In one embodiment, the lead  18  is a bipolar lead  18  including a pair of electrodes  50  located on an electrode region  54  of the lead body. In another embodiment, the lead  18  is a quadripolar lead  18  having four electrodes  50  located on an electrode region  54  of the lead body. In still other embodiments the lead  18  can have an electrode array including more than four electrodes  50 . Each conductor extending within the lead body  34  is adapted to be connected to an individual electrode  50  located on an electrode region  54  of the lead body  34  in a one-to-one manner allowing each electrode  50  to be individually addressable. Additionally, each electrode  50  located on the lead body  34  can be programmed by the IMD  22  to assume a positive (+) or negative (−) polarity to create a particular stimulation field when current, for example, is applied thereto. 
     According to various embodiments, the electrode  50  is adapted to transvascularly deliver an electrical stimulation pulse across the wall of the IJV  14  to the vagus nerve  6 . The electrode  50  can be a ring or partial ring electrode. In some embodiments, as shown in  FIG. 2 , the electrode  50  may include a masked portion  56  and an unmasked portion  58  having an electrically active surface  62 . Upon implantation of the lead  18  in the IJV  14 , the electrode region  54  of the lead  18  including the at least one electrode  50  is oriented such that the electrically active surface  62  of the electrode  50  is oriented in a direction towards the region of the vagus nerve  6  to be stimulated and the masked portion  56  of the electrode  50  is oriented away from the vagus nerve  6  so as to shield other areas of the anatomy from undesired or unintended stimulation. 
       FIGS. 3A and 3B  are schematic views of the fixation member  26  according to various embodiments of the present invention. As shown in  FIGS. 3A and 3B , the fixation member  26  is an elongated stent-like fixation member  26  that is provided separate from the lead  18 . In some embodiments, as shown in  FIG. 3A , the elongated stent-like fixation member  26  is generally cylindrical. In other embodiments, as shown in  FIG. 3B , the stent-like fixation member  26  includes a pre-formed concave channel  27  sized and shaped to receive a portion of the lead body  34  extending from a proximal end  28  to a distal end  29  of the stent-like fixation member  26 . The channel  27  is sized and shaped to receive a portion of a lead body such as, for example, lead body  34 . In one embodiment, the channel  27  has a generally C-shaped cross-section. In another embodiment, the channel  27  has a generally U-shaped cross-section. Additionally, in some embodiments, the channel  27  has an inner diameter x generally corresponding to or slightly larger than an outer diameter of the portion of the lead body to be received therein. In other embodiments, the stent-like structure defining the channel  27  is sufficiently resilient such that the channel  27  is adapted to expand such that the inner diameter x increases so as to accommodate a lead body having a larger diameter. 
     The stent-like fixation member  26 , according to the embodiments described above, can be constructed from a variety of biocompatible materials. In some embodiments, the stent-like fixation member  26  is constructed from a wire mesh such as, for example a stainless steel or Nitinol wire mesh. In other embodiments, the stent-like fixation member  26  can be constructed from an insulative, biocompatible polymer. In still another embodiment, the stent-like fixation member  26  can be constructed from a bio-resorbable polymer such that the stent-like fixation member  26  dissolves over time. Additionally, in some embodiments, the stent-like fixation member  26  can include an insulative coating or sheath provided over an outer surface of the stent-like fixation member  26  to prevent or avoid electrical contact with the lead&#39;s electrodes. 
     The elongated stent-like fixation member  26  is adapted to transition from a collapsed configuration for delivery to the implant site within the IJV  14  to an expanded configuration, as shown in  FIG. 1 . In one embodiment, the stent-like fixation member  26  is balloon-expandable. In another embodiment, the stent-like fixation member  26  is self-expanding. According to various embodiments, when in the expanded configuration, the stent-like fixation member  26  expands to an outer diameter dthat is greater than an inner diameter of the IJV  14  such that it places a sufficient amount of a radial expansion force on the vessel walls of the IJV  14  and on the electrode region  54  of the lead  18  so as to secure and stabilize the electrode region  54  of the lead  18  in the IJV  14 . While the stent-like fixation member  26  is illustrated as a cylinder, in some embodiments the stent-like fixation member  26  is sufficiently resilient such that it deforms or wraps around and engages an outer surface of the lead body  34  forming a channel around the lead body  34  and urging the lead body  34  into the vessel walls of the IJV  14 . In another embodiment, as shown in  FIG. 3B , the stent-like fixation member  26  includes a pre-formed concave channel  27  sized and shaped to engage an outer surface of the lead body  34 . Additionally, according to some further embodiments of the present invention, the stent-like fixation member  26  has a length l that is greater than an overall length of the electrode region  54 . 
     In some embodiments, the elongated stent-like member  26  can include a coating on its inner surface  64  and/or outer surface  66 . For example, the elongated stent-like member  26  can include a non-thrombogenic coating on its inner surface  64  and/or outer surface  66 . In still other embodiments, the elongated stent-like member  26  can include a drug eluting coating on its inner and/or outer surfaces  64  and  66 . 
     In another embodiment of the present invention, the elongated stent-like member  26  can include a polymer sheath lining the inner surface  64  and/or outer surface  66  of the stent-like member  26 . The polymer sheath can be fabricated from a material that is adapted to prevent tissue ingrowth through the stent structures. Additionally, the material from which the polymer sheath is fabricated is adapted to expand with the stent like fixation member  26  as the stent-like fixation member  26  is deployed. 
       FIGS. 4A-4C  are close up schematic views of the electrode region  54  of a lead  18  according to various embodiments secured within the IJV  14  adjacent a target region of the vagus nerve  6  using a stent-like fixation member  26 , such as described in detail above according to the various embodiments. The electrode region  54  can be a portion of the lead body  34  located between the proximal end  38  and the distal end  42  of the lead body  34 . In one embodiment, the electrode region  54  is located at a distal region  68  of the lead body  34 , as shown in  FIGS. 4A-4C . In another embodiment, the electrode region  54  can be located on a middle region of the lead body  34  (not shown). In some embodiments, the lead  18  can have more than one electrode region  54 . 
     In one embodiment, as shown in  FIG. 4A , the electrode region  54  of the lead  18  is a generally straight portion of the lead body  34  including one or more electrodes  50 . The electrode region  54  of the lead  18  can be delivered to the implant site within the IJV  14  using a variety of techniques know to those of skill in the art. The electrode region  54  is oriented within the IJV such that the electrically active region (see for example,  FIG. 2 ) of the electrode  50  is oriented in a direction towards the vagus nerve  6 . The stent-like fixation member  26  is then delivered to a location adjacent the electrode region  54  and expanded such that it contacts and engages the electrode region  54 , urging the electrically active region of at least one of the electrodes  50  located on the distal portion into contact with the vessel wall  70  adjacent the vagus nerve  6 . In some embodiments, partial masking of the electrode(s)  50  or an insulative coating or sheath provided over the outer surface  66  of the stent-like member  26  can be used to insulate the stent-like member  26  from the electrical contact with the electrode(s)  50 . In another embodiment, the stent-like member  26  can be a non-conductive, polymeric stent-like fixation member. 
     In other embodiments, as shown in  FIGS. 4B and 4C , the electrode region  54  of the lead  18  is a shaped region  80  of the lead body  34  including one or more electrodes  50 . The shaped region  80  of the lead body  34  can include a variety of pre-formed shapes including two dimensional shapes such as, for example, the two-dimensional sine wave  84  shown in  FIG. 4B  or three-dimensional shapes such as the spiral shape  88  shown in  FIG. 4C . The shaped region  80  of the lead body  34 , in addition to the stent-like fixation member  26 , can be used to further secure and stabilize the electrode region  54  of the lead  18  in the IJV  14  such that the electrically active surface of at least one electrode  50  located on the electrode region  54  is oriented in a direction towards the region of the vagus nerve  6  to be stimulated. 
     As shown in  FIGS. 4A-4C , the stent-like fixation member  26  is independent and separate from the lead  18 . According to some embodiments, as shown in  FIGS. 4A and 4C , the stent-like fixation member  26  is delivered separately to a location alongside the electrode region  54  of the lead  18  and then expanded against the electrode region  54 , urging the electrode region  54  into the vessel wall  70  adjacent the vagus nerve  6  to secure and stabilize the electrode region  54  of the lead  18  within the IJV  14 . In other embodiments, as shown in  FIG. 4C , the stent-like fixation member  26  can be inserted within the shaped region  80  of the lead body  34  and then expanded to secure and stabilize the shaped region  80  of the lead body  34  within the IJV  14 . More particularly, the stent-like fixation member  26  is inserted into a lumen  92  formed by the spiral  88  and then expanded such that the spiral  88  wraps around an outer surface  66  of the stent-like fixation member  26 , forcing at least a portion of the spiral  88  including an electrode  50  located thereon into the vessel wall  70  adjacent the vagus nerve  6 . In some embodiments, partial masking of the electrode(s)  50  or an insulative coating or sheath provided over the outer surface  66  of the stent-like fixation member  26  can be used to insulate the stent-like fixation member  26  the electrical contact with the electrode(s)  50 . In another embodiment, the stent-like fixation member  26  itself can be fabricated from an insulative material, polymeric material such that it does not make electrical contact with the electrode(s). 
     In some embodiments, the stent-like fixation member  26  can be used to further orient the electrode region  54  of the lead body  34  within the IJV  14 . The stent-like fixation member  26  can be at least partially deployed from a delivery catheter until it frictionally engages at least a portion of the electrode region  54  of the lead body  34 . Once frictionally engaged with the electrode region  54 , the partially expanded fixation member  26  can be rotated, thereby causing rotation of the electrode region  54  of the lead body  34  within the IJV  14 . In one further embodiment, the stent-like fixation member  26  may be provided with a tacky or adhesive surface coating over a least a portion of its outer surface  66  to enhance frictional engagement of the stent-like fixation member  26  with the electrode region  54  of the lead body  34 . In another further embodiment, the stent-like fixation member  26  can include one or more prongs or hooks configured to engage the lead body  34  in a cooperative manner. In still yet another embodiment, as shown in  FIG. 4C , the lead body  34  can include one or more projections  94  such as prongs, hooks or tines that are adapted to engage the mesh outer surface  66  of the stent-like fixation member  26 . Once the stent-like fixation member  26  is engaged with the lead body  34 , the stent-like fixation member  26  can be rotated, thereby causing rotation of the lead body  34 . 
       FIG. 5A  is a close-up schematic view of a stent-like fixation member  126  deployed in a patient&#39;s IJV  14  prior to the delivery and implantation of a lead  118 .  FIG. 5B  is a close-up, schematic view of stent-like fixation member  126  and lead  118  after delivery and implantation of the lead  118 . As shown in  FIG. 5A , the stent-like fixation member  126  includes many of those same features as the fixation members  26  described above in reference to  FIGS. 3A and 3B  and also includes a channel  127 . The channel  127  extends from a proximal end  128  to a distal end  129  of the stent-like fixation member  126 . According to various embodiments, the channel  127  is sized and shaped to engage and receive the lead body  134  therein. In one embodiment, the channel  127  has a generally C-shaped cross-section. In another embodiment, the channel  127  has a generally U-shaped cross-section. Additionally, the channel  127  has an inner diameter that generally corresponds to and/or is slightly larger than the outer diameter of the lead body  134 . 
     According to some embodiments, as best shown in  FIG. 5A , the stent-like fixation member  126  also includes a tether  150  coupled to the distal end  129  of stent-like fixation member  126  and extending within the channel  127 . The tether  150  facilitates delivery of the lead body  134  within the channel  127 . The tether  150  can be made from a variety of materials. For example, in one embodiment, the tether  150  can be fabricated from a polymer or a material similar to those used to fabricate sutures. In other embodiments, the tether can be fabricated from a bio-resorbable material that is capable of being dissolved over time in the body environment. In still yet another embodiment, the tether  150  can include one or conductors extending within the tether  150  from a proximal end to a distal end surrounded by one or more layers of an insulation. 
     In some embodiments, the lead body  134  includes a lumen (not shown) extending within the lead body from its proximal end to its distal end to facilitate delivery of the lead  118  over the tether  150  to be received within the channel  127  as shown in  FIG. 5B . In one embodiment, the lead body  134  is delivered over the tether  150  and received within the channel  127  such that a distal end  154  of the lead body  134  is adjacent to the distal end  129  of the stent-like fixation member  126 . The channel  127  and tether  150  of the stent-like fixation member  126  cooperates with the lead body  134  to secure and stabilize the lead body  134  at a target location within the IJV  14  adjacent the vagus nerve  6 . More particularly, the channel  127  and tether  150  cooperate to secure and stabilize the lead body  134  at the target location in the IJV such that at least one electrode  158  is oriented in a direction towards the vagus nerve  6 . 
     In another embodiment, the lead body  134  can include a loop feature or other guide feature that facilitates advancement of the lead body  134  alongside the tether  150  using the tether  150  as a guide or track. In this embodiment, the lead body  134  can be advanced alongside the tether  150  using a stylet or other delivery tool to deliver the lead body  134  to the desired location. 
       FIG. 6  is a close-up schematic view of a system  200  including stent-like member  226  deployed within a patient&#39;s IJV  14  and used to secure and stabilize a lead  218  at a location adjacent a region of the vagus nerve  6  to be stimulated according to yet another embodiment of the present invention. As shown in  FIG. 6 , the stent-like member  226  is similar to stent-like members  26  and  126  described above according to the various embodiments of the present invention and includes many or all of those same features. The stent-like member  226  is expanded such that it contacts the vessel walls  70  of the IJV  14  such that it is secured and stabilized within the IJV  14  adjacent the vagus nerve  6 . According to one embodiment, as shown in  FIG. 6 , the stent-like member  226  includes a tether  230  coupled to and extending in a proximal direction away from its proximal end  234 . 
     The tether  230  provides a track or guide for delivery of the lead  218  to the implant location within the IJV  14  adjacent the vagus nerve  6 . In one embodiment, the lead  218  can include at least one lumen (not shown) that facilitates its delivery over the tether  230 . In another embodiment, the lead  218  can include a loop feature or other guide feature that facilitates delivery of the lead  218  alongside the tether  230  using the tether  230  as a guide or track. The lead  218  can include a pre-formed shape  228  having a two-dimensional or three dimensional shape. As shown in  FIG. 6 , the pre-formed shape  228  can be a three dimensional spiral shape. According to various embodiments, one or more electrodes  232  can be located on the shaped region  228 . 
     In one embodiment, the shaped region  228  is adapted to transition from a collapsed configuration suitable for delivery to an expanded configuration. Tension can be placed on the tether  230  to retain the lead in a collapsed configuration during delivery of the lead  218  over the tether  230 . The lead  218  transitions from its collapsed configuration to its expanded configuration where it returns to its pre-formed shape by relaxing the tension on the tether  230 . In the expanded configuration, the shaped region  228  places a sufficient lateral force on the vessel walls  70  so as to secure and stabilize the lead  218  at the implant location within the IJV, urging at least one electrode  232  into the vessel walls  70 . 
     In one embodiment, as shown in  FIG. 6 , the tether  230  also includes a stop  240 . The stop  240  is located at a fixed distance relative to the proximal end  234  of the stent-like fixation member  226 . During deployment of the system  200 , the lead  218  is advanced over the tether  230  until it reaches the stop  240 . The lead  218  is located proximal to the stent-like fixation member  226  such that the distance between the distal end  244  of the lead  218  and the proximal end  234  of the stent-like member  226  is fixed. In one embodiment, to further secure and stabilize the lead  218  at the implantation location within the IJV  14 , the lead  128  can be secured at the distal stop  240  and the proximal end of the lead  218  by the application of the a cap or by tying a knot in the tether  230  as the tether  230  exits the proximal end of the lead  218 . As a result, movement of the lead  218  over the tether  230  is prevented once the lead  218  has been implanted. 
     In another embodiment, the proximal end  234  of the stent-like fixation member  226  can serve as the stop  240 . In this example, the lead  218  is advanced along or over the tether  230  until the distal end  244  of the lead  218  reaches the proximal end  234  of the stent-like fixation member  226 . The lead  218  can then be secured and stabilized at the implantation location within the IJV by capping or tying a knot in the tether as it exits the proximal end of the lead  218  as discussed above. 
     In other embodiments of the present invention as shown in  FIGS. 7A-7C , a stent-like fixation member  326  can include one or more electrodes  360  located on an outer surface  366  of the stent-like fixation member  326  and operatively coupled to one or more conductors extending within the tether  330  from the proximal end to the distal end of the tether  330 . The stent-like fixation member  326  includes many or all of the same features as the stent-like fixation members  26 ,  126  and  226  described above according to the various embodiments. During delivery, the stent-like fixation member  326  can be partially deployed from a delivery catheter  356  so that the electrodes  360  can be positioned closer to the vessel walls  70  of the IJV  14 . As shown in  FIG. 7A , the partially deployed stent-like fixation member  326  can be rotated and repositioned until an optimal location for delivery of stimulation to the vagus nerve  6  has been indentified using the electrodes  360  located on an outer surface  366  of the stent-like fixation member  326 . In some embodiments, the electrode(s)  360  can be used to acutely stimulate the vagus nerve  6  until a desired threshold for physiological response used to evaluate the efficacy of the stimulation has been achieved. In other embodiments, the electrode(s)  260  can be used as sensing electrodes (sensing nerve traffic signal, artery pulsation via impedance change, etc.) in order to locate the nerve for final lead positioning. Once the region of the nerve  6  to be stimulated has been identified, the stent-like member  326  can then be fully expanded at the implantation location as shown in  FIG. 7B . After expansion of the stent-like member  326 , the lead body  318  can then be delivered over or alongside the tether  330  and received within the channel  327  such that electrode(s)  350  located on the lead  318  are positioned within the internal jugular vein adjacent the vagus nerve  6  as shown in  FIG. 7C . Electrical stimulus therapy can then be delivered to the vagus nerve  6  using the electrodes  350  located on the lead  318 . 
       FIGS. 8A and 8B  are close-up schematic views of a stent-like fixation member  426  according to yet another embodiment of the present invention. The stent-like fixation member  426  can include many or all of the same features as the stent-like fixation members  26 ,  126 ,  226  and  326  described above according to the various embodiments. In addition, as shown in  FIGS. 8A and 8B , the stent-like fixation member  426  includes one or more electrodes  460  located on an outer surface  466  of the stent-like fixation member  426  and operatively coupled to one or more conductors extending within the tether  430  coupled to the stent-like fixation member  426 . 
     During delivery, as shown in  FIG. 8A , the stent-like fixation member  426  can be partially deployed from a delivery catheter  456  so that the electrodes  460  can be positioned closer to the vessel walls  70  of the IJV  14 . As indicated in  FIG. 8A , the partially deployed stent-like fixation member  426  can be rotated and repositioned until an optimal location for delivery of stimulation to the vagus nerve  6  has been identified using the electrodes  460  located on an outer surface  466  of the stent-like fixation member  426 . The stent-like member  426  can then be fully expanded at the implantation location as shown in  FIG. 8B . After expansion of the stent-like member  426 , the lead  418  can then be delivered over or alongside the tether  430 . The lead  418  would track the tether  430  and stop near the proximal electrode  460  to position the electrodes  450  located on the lead  418  at the desired location adjacent the vagus nerve  6 . In one embodiment, the electrodes  450  are located on a straight portion  470  of the lead  418  such that they are adapted to be placed in parallel alignment with the adjacent region of the vagus nerve  6 . In a further embodiment, the lead  418  can include a pre-formed region such as a pre-formed spiral region  476  as shown in  FIG. 8B  which can be used to further secure and stabilize the electrode region of the lead  418  at the desired position adjacent the vagus nerve  6 . As described above, the tether  430  can be capped or knotted at the proximal end where the tether  430  exits the proximal end of the lead as a further mechanism for securing and stabilizing the lead  418  at the desired position. 
       FIG. 9  outlines a method  500  of securing and stabilizing a medical electrical lead, such as described above according to the various embodiments, at a location within the IJV  14  for stimulating a region of the vagus nerve  6 . According to one embodiment of the method  500 , the lead is advanced within a patient&#39;s IJV  14  to a location adjacent the region of the vagus nerve  6  to be stimulated (Block  510 ). The lead can be delivered to the target location using a variety of lead delivery techniques. In one embodiment, the lead is advanced over a guidewire to the location within the IJV  14 . In other embodiments, the lead can be delivered using a guide catheter or a stylet. Acute stimulation of the vagus nerve  6  can be used to determine whether placement of the lead at that location results in optimal stimulation of the vagus nerve  6  to produce a desired physiological effect. Physiological effects that could be produced and subsequently monitored include laryngeal muscle vibration from activation of the RLN (branch of the vagus nerve), heart rate, blood pressure, voice alteration or electroencephalogram signals. The lead can be repositioned as necessary until an optimal position for stimulation resulting in a desired physiological effect is identified. 
     Next, according to one embodiment, a delivery catheter can be used to advance a stent-like member to the location adjacent the electrode region on the lead (Block  520 ). The stent-like member is retained in a collapsed configuration during delivery by the delivery catheter. The stent-like member is then deployed from the delivery catheter and the stent-like member is transitioned from its collapsed configuration to an expanded configuration (Block  530 ). In one embodiment, the stent-like member is transitioned by the expansion of a balloon inserted within the stent-like member. In another embodiment, the stent-like member is configured to self-expand upon deployment from the delivery catheter. In the expanded configuration, the stent-like member engages an electrode region of the lead, urging the electrode region including at least one electrode into a vessel wall adjacent the region of the vagus nerve  6  to be stimulated (Block  530 ). In a further embodiment, once deployed, the stent-like member can be used to reposition the electrode region of the lead by rotating the stent-like fixation member in clock-wise or counter clockwise direction (Block  540 ). 
     In yet another embodiment of the method, the stent-like fixation member can be partially deployed from the delivery catheter until it contacts and engages an electrode region of the lead. The stent-like member can then be used to reposition the electrode region by rotating the electrode region in a clockwise or counter clockwise manner until an optimal location for stimulation of the vagus nerve is achieved. The stent-like member can then be fully deployed from the delivery catheter to secure and stabilize the electrode region of the lead at that location. 
     In still yet another embodiment of the method, the lead can include a pre-formed, shaped region. The pre-formed, shaped region can have a two-dimensional or three-dimensional shape. The pre-formed, shaped region provides an additional mechanism for securing and stabilizing the lead within the IJV  14 . The lead can be advanced to a target location within the IJV  14  adjacent the vagus nerve  6  using a stylet or guidewire. Upon reaching the target location, the guidewire or stylet is removed from the lead such that the shaped region of the lead returns to its pre-formed shape and is secured within the IJV  14 . The stent-like member is then advanced to a location adjacent to or within the pre-formed shape and then expanded urging the pre-shaped region of the lead against the vessel walls of the IJV  14 , further securing and stabilizing the lead within the IJV  14 . For example, in one embodiment, the pre-formed shaped region of the lead is a spiral and the stent-like member is advanced to a position within the lumen defined by the spiral and then transitioned from its collapsed configuration to its expanded configuration. 
       FIG. 10  outlines a method  600  of securing and stabilizing a medical electrical lead according to another embodiment of the present invention. The method includes advancing a stent-like fixation member retained in a collapsed configuration within a delivery catheter to a location within the internal jugular vein and deploying the stent-like member from the catheter such that the stent-like member transitions from the collapsed configuration to an expanded configuration (Blocks  610  and  620 ). The stent-like fixation member includes a concave channel sized and shaped to receive a portion of a lead therein extending from a proximal end to a distal end of the stent-like member. The stent-like member also includes a tether coupled to a distal end of the stent-like member and extending in a proximal direction away from the stent-like member (Block  610 ). 
     After the stent-like member is expanded to secure and stabilize it within the IJV  14 , a lead is then advanced over or alongside the tether until it is received within the channel of the stent-like member (Block  630 ). In one embodiment, the portion of the lead that is advanced and received within the channel includes at least one electrode. 
     Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.