Patent Publication Number: US-11660446-B2

Title: Delivery devices and methods for leadless cardiac devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/935,611, filed Mar. 26, 2018, which is a continuation of U.S. application Ser. No. 14/919,310, filed Oct. 21, 2015, now U.S. Pat. No. 9,956,400, which claims priority under 35 U.S.C. § 119 to U.S. Provisional Application Ser. No. 62/067,140, filed Oct. 22, 2014, the entirety of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure pertains to medical devices, and methods for manufacturing and/or using medical devices. More particularly, the present disclosure pertains to leadless cardiac devices and methods, such as leadless pacing devices and methods, and delivery devices and methods for such leadless devices. 
     BACKGROUND 
     A wide variety of medical devices have been developed for medical use, for example, cardiac use. Some of these devices include catheters, leads, pacemakers, and the like, and delivery devices and/or systems used for delivering such devices. These devices are manufactured by any one of a variety of different manufacturing methods and may be used according to any one of a variety of methods. Of the known medical devices, delivery systems, and methods, each has certain advantages and disadvantages. There is an ongoing need to provide alternative medical devices and delivery devices as well as alternative methods for manufacturing and using medical devices and delivery devices. 
     BRIEF SUMMARY 
     This disclosure provides design, material, manufacturing method, and use alternatives for medical devices, including delivery devices. 
     In a first example, a delivery device for delivering an implantable leadless pacing device may comprise an outer tubular member including a lumen extending from a proximal end to a distal end thereof, an inner tubular member including a lumen extending from a proximal end to a distal end thereof, the inner tubular member slidably disposed within the lumen of the outer tubular member, a distal holding section extending distally of a distal end of the inner tubular member, the distal holding section defining a cavity therein for receiving an implantable leadless pacing device, a handle assembly including at least a first hub portion affixed adjacent to the proximal end of the outer tubular member and intermediate second hub portion affixed adjacent to the proximal end of the inner tubular member, and a first locking mechanism disposed within the handle assembly, wherein the first locking mechanism is configured to releasably couple the first hub portion and the second hub portion. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may have a locked position and an unlocked position wherein the inner tubular member is held in tension in the locked position. 
     Alternatively or additionally to any of the examples above, in another example, the outer tubular member may be held in compression in the locked position. 
     Alternatively or additionally to any of the examples above, in another example, the first hub portion and the second hub portion may be individually slidable and rotatable when the first locking mechanism is in an unlocked configuration. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may be selected from the group of a snap lock, a threaded engagement, or a quick connect locking feature. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may comprise a bayonet style locking mechanism. 
     Alternatively or additionally to any of the examples above, in another example, the second hub portion may comprise a groove positioned adjacent a distal end of the second hub portion, the groove configured to receive an inwardly extending protrusion of the first hub portion. 
     Alternatively or additionally to any of the examples above, in another example, the groove may comprise a first portion, a second portion extending generally orthogonal to the first portion, and a serif positioned at an end of the second portion. 
     Alternatively or additionally to any of the examples above, in another example, disposing the protrusion within the serif may releasably couple the outer tubular member and the inner tubular member such that longitudinal or rotational actuation of either of the outer tubular member or the inner tubular member results in corresponding actuation of both the outer tubular member and the inner tubular member. 
     Alternatively or additionally to any of the examples above, in another example, disposing the protrusion within the serif may place the inner tubular member in tension and the outer tubular member in compression. 
     Alternatively or additionally to any of the examples above, in another example, the device may further comprise a push member slidably disposed within the lumen of the inner tubular member. 
     Alternatively or additionally to any of the examples above, in another example, the device may further comprise a third hub portion affixed adjacent to a proximal end of the push member. 
     Alternatively or additionally to any of the examples above, in another example, the device may further comprise a second locking mechanism disposed within the handle assembly. 
     Alternatively or additionally to any of the examples above, in another example, the third hub portion may be slidable and rotatable independent of either of the first hub portion or the second hub portion when the second locking mechanism is in an unlocked configuration. 
     Alternatively or additionally to any of the examples above, in another example, longitudinal or rotational actuation of either of the inner tubular member or the push member may result in corresponding actuation of both the inner tubular member and the push member when the second locking mechanism is in a locked configuration. 
     Alternatively or additionally to any of the examples above, in another example, a method of releasably coupling an outer tubular member affixed to a first hub portion to an inner tubular member affixed to a second hub portion of a delivery device may comprise rotating the second hub portion relative to the first hub portion, the first hub portion having an inwardly extending protrusion, to align the protrusion with a first portion of a groove on a distal portion of the second hub portion, proximally retracting the second hub portion to advance the protrusion into the first portion of the groove, rotating the second hub portion relative to the first hub portion about a longitudinal axis of the first hub portion to advance the protrusion along a second portion of the groove, the second portion of the groove extending generally orthogonal to the first portion of the groove, and disposing the protrusion within a serif positioned at an end of the second portion of the groove. 
     Alternatively or additionally to any of the examples above, in another example, a delivery device for delivering an implantable leadless pacing device may comprise an outer tubular member including a lumen extending from a proximal end to a distal end thereof, an inner tubular member including a lumen extending from a proximal end to a distal end thereof, the inner tubular member slidably disposed within the lumen of the outer tubular member, a distal holding section extending distally of a distal end of the inner tubular member, the distal holding section defining a cavity therein for receiving an implantable leadless pacing device, a handle assembly including at least a first hub portion affixed adjacent to the proximal end of the outer tubular member and a second hub portion affixed adjacent to the proximal end of the inner tubular member, and a first locking mechanism disposed within the handle assembly, wherein the first locking mechanism is configured to releasably couple the first hub portion and the second hub portion. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may have a locked position and an unlocked position wherein the inner tubular member is held in tension in the locked position. 
     Alternatively or additionally to any of the examples above, in another example, the outer tubular member may be held in compression in the locked position. 
     Alternatively or additionally to any of the examples above, in another example, the first hub portion and the second hub portion may be individually slidable and rotatable when the first locking mechanism is in an unlocked configuration. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may comprise a bayonet style locking mechanism. 
     Alternatively or additionally to any of the examples above, in another example, the second hub portion may comprise a groove positioned adjacent a distal end of the second hub portion, the groove configured to receive an inwardly extending protrusion of the first hub portion. 
     Alternatively or additionally to any of the examples above, in another example, the groove may comprise a first portion, a second portion extending generally orthogonal to the first portion, and a serif positioned at an end of the second portion. 
     Alternatively or additionally to any of the examples above, in another example, disposing the protrusion within the serif may releasably couple the outer tubular member and the inner tubular member such that longitudinal or rotational actuation of either of the outer tubular member or the inner tubular member results in corresponding actuation of both the outer tubular member and the inner tubular member. 
     Alternatively or additionally to any of the examples above, in another example, disposing the protrusion within the serif may place the inner tubular member in tension and the outer tubular member in compression. 
     Alternatively or additionally to any of the examples above, in another example, the device may further comprise a push member slidably disposed within the lumen of the inner tubular member. 
     Alternatively or additionally to any of the examples above, in another example, the device may further comprise a third hub portion affixed adjacent to a proximal end of the push member. 
     Alternatively or additionally to any of the examples above, in another example, the device may further comprise a second locking mechanism disposed within the handle assembly. 
     Alternatively or additionally to any of the examples above, in another example, the third hub portion may be slidable and rotatable independent of either of the first hub portion or the second hub portion when the second locking mechanism is in an unlocked configuration. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may be selected from the group of a snap lock, a threaded engagement, or a quick connect locking feature. 
     Alternatively or additionally to any of the examples above, in another example, longitudinal or rotational actuation of either of the inner tubular member or the push member may result in corresponding actuation of both the inner tubular member and the push member when the second locking mechanism is in a locked configuration. 
     Alternatively or additionally to any of the examples above, in another example, a delivery device for delivering an implantable leadless pacing device may comprise an outer tubular member including a lumen extending from a proximal end to a distal end thereof, an inner tubular member including a lumen extending from a proximal end to a distal end thereof, the inner tubular member slidably disposed within the lumen of the outer tubular member, a push member having a proximal end and a distal end, the push member slidably disposed within the lumen of the inner tubular member, a distal holding section extending distally of a distal end of the inner tubular member, the distal holding section defining a cavity therein for receiving an implantable leadless pacing device, a handle assembly including a distal hub portion affixed adjacent to the proximal end of the outer tubular member, an intermediate hub portion affixed adjacent to the proximal end of the inner tubular member, and a proximal hub portion affixed adjacent to the proximal end of the push member, the distal hub portion, the intermediate hub portion, and the proximal hub portion arranged in a telescoping configuration such that each of the distal hub portion, intermediate hub portion, and proximal hub portion are capable of being longitudinally and rotationally actuated individually, and a first locking mechanism disposed between the distal hub portion and the intermediate hub portion, wherein the first locking mechanism is configured to releasably couple the distal hub portion and the intermediate hub portion. 
     Alternatively or additionally to any of the examples above, in another example, the first locking mechanism may be user actuatable between an unlocked configuration and a locked configuration. 
     Alternatively or additionally to any of the examples above, in another example, when in the locked configuration, the intermediate hub portion may be proximally retracted to place the inner tubular member in tension and the outer tubular member in compression. 
     Alternatively or additionally to any of the examples above, in another example, a method of releasably coupling an outer tubular member affixed to a first hub portion and an inner tubular member affixed to a second hub portion of a delivery device may comprise rotating a the first hub portion in a first direction relative to the second hub portion, the first hub portion having an inwardly extending protrusion, to align the protrusion with a first portion of a groove on a distal portion of a second hub portion, advancing the protrusion into the first portion of the groove, rotating the second hub portion relative to the first hub portion and about a longitudinal axis of the first hub portion in a first direction to advance the protrusion along a second portion of the groove, the second portion of the groove extending generally orthogonal to the first portion of the groove, and disposing the protrusion within a serif positioned at an end of the second portion of the groove. 
     Alternatively or additionally to any of the examples above, in another example, disposing the protrusion within the serif may releasably couple the inner tubular member and the outer tubular member such that longitudinal or rotational actuation of either of the outer tubular member or the inner tubular member results in corresponding actuation of both the outer tubular member and the inner tubular member. 
     Alternatively or additionally to any of the examples above, in another example, the method may further comprise disengaging the protrusion from the serif, rotating the second hub portion relative to the first hub portion in a second direction, the second direction generally opposite to the first direction, to advance the protrusion along a second portion of the groove towards the first portion of the groove, and distally advancing the second hub portion to disengage the protrusion from the first portion of the groove, wherein disengaging the protrusion from the first portion of the groove uncouples the inner tubular member and the outer tubular member. 
     The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify some of these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure may be more completely understood in consideration of the following detailed description in connection with the accompanying drawings, in which: 
         FIG.  1    is a plan view of an example leadless pacing device implanted within a heart; 
         FIG.  2    is a perspective view of an example delivery device for an implantable leadless cardiac pacing device; 
         FIG.  3    is a partial cross-sectional side view of the distal portion of the delivery device of  FIG.  2   ; 
         FIG.  3 A  is a partial cross-sectional side view of a portion of a distal portion of another illustrative delivery device; 
         FIG.  3 B  is a partial cross-sectional side view of a portion of a distal portion of another illustrative delivery device; 
         FIG.  3 C  is a partial perspective view of a portion of a distal portion of another illustrative delivery device; 
         FIG.  4    is a cross-sectional side view of the proximal portion of the delivery device of  FIG.  2   ; 
         FIG.  5    is a perspective view of the proximal portion of the delivery device of  FIG.  2    with portions removed; 
         FIGS.  6 A- 6 E  are a schematic view of a locking mechanism of the proximal portion of the delivery device of  FIG.  2   ; and 
         FIG.  7    is a perspective view of the proximal portion of the delivery device of  FIG.  2    with portions removed. 
     
    
    
     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 invention 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. 
     DETAILED DESCRIPTION 
     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 terms “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. 
     It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include one or more particular features, structures, and/or characteristics. However, such recitations do not necessarily mean that all embodiments include the particular features, structures, and/or characteristics. Additionally, when particular features, structures, and/or characteristics are described in connection with one embodiment, it should be understood that such features, structures, and/or characteristics may also be used connection with other embodiments whether or not explicitly described unless clearly stated to the contrary. 
     The following detailed description should be read with reference to the drawings in which similar structures 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. 
     Cardiac pacemakers provide electrical stimulation to heart tissue to cause the heart to contract and thus pump blood through the vascular system. Conventional pacemakers typically include an electrical lead that extends from a pulse generator implanted subcutaneously or sub-muscularly to an electrode positioned adjacent the inside or outside wall of the cardiac chamber. As an alternative to conventional pacemakers, self-contained or leadless cardiac pacemakers have been proposed. Leadless cardiac pacemakers are small capsules typically fixed to an intracardiac implant site in a cardiac chamber. The small capsule typically includes bipolar pacing/sensing electrodes, a power source (e.g. a battery), and associated electrical circuitry for controlling the pacing/sensing electrodes, and thus provide electrical stimulation to heart tissue and/or sense a physiological condition. The capsule may be delivery to the heart using a delivery device which may be advanced through a femoral vein, into the inferior vena cava, into the right atrium, through the tricuspid valve, and into the right ventricle. Accordingly, it may be desirable to provide delivery devices which facilitate advancement through the vasculature. 
       FIG.  1    illustrates an example implantable leadless cardiac pacing device  10  (e.g., a leadless pacemaker) implanted in a chamber of a heart H, such as the right ventricle RV. The implantable device  10  may include a shell or housing  12  having a proximal end  14  and a distal end  16 . The implantable device  10  may include a first electrode  20  positioned adjacent to the distal end  16  of the housing  12  and a second electrode  22  positioned adjacent to the proximal end  14  of the housing  12 . For example, housing  12  may include a conductive material and may be insulated along a portion of its length. A section along the proximal end  14  may be free of insulation so as to define the second electrode  22 . The electrodes  20 ,  22  may be sensing and/or pacing electrodes to provide electro-therapy and/or sensing capabilities. The first electrode  20  may be capable of being positioned against or may otherwise contact the cardiac tissue of the heart H while the second electrode  22  may be spaced away from the first electrode  20 , and thus spaced away from the cardiac tissue. 
     The implantable device  10  may include a pulse generator (e.g., electrical circuitry) and a power source (e.g., a battery) within the housing  12  to provide electrical signals to the electrodes  20 ,  22  and thus control the pacing/sensing electrodes  20 ,  22 . Electrical communication between the pulse generator and the electrodes  20 ,  22  may provide electrical stimulation to heart tissue and/or sense a physiological condition. 
     The implantable device  10  may include a fixation mechanism  24  proximate the distal end  16  of the housing  12  configured to attach the implantable device  10  to a tissue wall of the heart H, or otherwise anchor the implantable device  10  to the anatomy of the patient. As shown in  FIG.  1   , in some instances, the fixation mechanism  24  may include one or more, or a plurality of hooks  26  anchored into the cardiac tissue of the heart H to attach the implantable device  10  to a tissue wall. In other instances, the fixation mechanism  24  may include one or more, or a plurality of passive tines, configured to entangle with trabeculae within the chamber of the heart H and/or a helical fixation anchor configured to be screwed into a tissue wall to anchor the implantable device  10  to the heart H. 
     The implantable device  10  may include a docking member  30  proximate the proximal end  14  of the housing  12  configured to facilitate delivery and/or retrieval of the implantable device  10 . For example, the docking member  30  may extend from the proximal end  14  of the housing  12  along a longitudinal axis of the housing  12 . The docking member  30  may include a head portion  32  and a neck portion  34  extending between the housing  12  and the head portion  32 . The head portion  32  may be an enlarged portion relative to the neck portion  34 . For example, the head portion  32  may have a radial dimension from the longitudinal axis of the implantable device  10  which is greater than a radial dimension of the neck portion from the longitudinal axis of the implantable device  10 . The docking member  30  may be configured to facilitate delivery of the implantable device  10  to the intracardiac site and/or retrieval of the implantable device  10  from the intracardiac site. Other docking members  30  are contemplated. 
     One aspect of the current disclosure relates to the delivery device and/or system used, for example, to deliver device  10  to a suitable location within the anatomy (e.g., the heart). As may be appreciated, the delivery device may need to be navigated through relatively tortuous anatomy to deliver the device  10  to a suitable location. For instance, in some embodiments, the delivery device may be advanced through the vasculature to a target region. In some example cases the device may be advanced through a femoral vein, into the inferior vena cava, into the right atrium, through the tricuspid valve, and into the right ventricle. The target region for the delivery of the device  10  may be a portion of the right ventricle, for example, a portion of the right ventricle near the apex of the heart. The target region may also include other regions of the heart (e.g., right atrium, left atrium, or left ventricle), blood vessels, or other suitable targets. It may be desirable to provide the delivery system with certain features that may allow for easier or better control for navigation or delivery purposes. 
       FIG.  2    is a perspective view of an illustrative delivery device  100 , such as a catheter, that may be used to deliver the device  10 . The delivery device  100  may include an outer tubular member  102  having a proximal section  104  and a distal section  106 . An inner tubular member  110  may be slidably disposed within a lumen  150  of the outer tubular member  102  (see e.g.  FIGS.  3  and  4   ). A distal holding section  108  may be attached to a distal end portion  114  of the inner tubular member  110 . The delivery device  100  may also include a handle assembly  120  positioned adjacent to the proximal section of the outer tubular member  102 . In some embodiments, the outer tubular member  102  may include at least a section thereof that has an outer diameter D 2  that is less than the outer diameter D 1  of at least a portion of the holding section  108  (see e.g.  FIG.  3   ). 
     The handle assembly  120  may include a first or distal hub portion  126  attached to the proximal end section  104  of the outer tubular member  102 , a second or intermediate hub portion  128  attached to a proximal end section of the inner tubular member  110 , and a third or proximal hub portion  130  attached to a proximal end section of a push member  116  (see e.g.  FIG.  3   ). The first hub portion  126 , second hub portion  128 , and third hub portion  130  may be positioned in a generally telescoping arrangement and slidable relative to each other. As will be discussed in more detail below, each of the first hub portion  126 , the second hub portion  128 , and the third hub portion  130  may be slidable and rotatable relative to each other such that the outer tubular member  102 , inner tubular member  110 , and push member  116  may be individually actuated. In some instances, it may be desirable to move the outer tubular member  102 , inner tubular member  110  and push member  116  simultaneously. The handle assembly  120  may include a first locking mechanism  132  to releasably couple the outer tubular member  102  to the inner tubular member  110 , as will be discussed in more detail below. The handle assembly  120  may also include a second locking mechanism  134  to releasably couple the inner tubular member  110  to the push member  116 , as will be discussed in more detail below. 
     The distal holding section  108  may be configured to receive the implantable device  10  therein. For example, referring to  FIG.  3   , which illustrates a cross-sectional view of a distal portion of delivery device  100 , the holding section  108  may define a cavity  142  for slidably receiving the implantable device  10 , and may include a distal opening  144  for slidable insertion and/or extraction of the implantable device  10  into and/or out of the cavity  142 . 
     The distal holding section  108  may include a body portion  138  and a distal tip portion  140  that may be, for example, configured to be atraumatic to anatomy, such as a bumper tip. For example, as the catheter is navigated through the anatomy, the distal tip may come into contact with anatomy. Additionally, when the catheter is used to deliver the device, the tip  140  of the delivery device  100  will likely come into contact with tissue adjacent the target cite (e.g. cardiac tissue of the heart). A hard distal tip formed of the material of the outer tubular member  102  and/or inner tubular member  110  may injure a vessel wall or cardiac tissue. As such, it may be desirable to provide the delivery device  100  with a softer distal tip  140  that can be introduced into the anatomy and come into contact with anatomy adjacent the target cite without causing unnecessary trauma. 
     For example, the distal tip  140  may be made of a material that is softer than the body portion  138  of the distal holding section. In some cases, the distal tip  140  may include a material that has a durometer that is less than the durometer of the material of the body portion  138 . In some particular embodiments, the durometer of the material used in the distal tip  140  may be in the range of about 5 D to about 70 D, or for example, in the range of about 25 D to about 65 D. Additionally, the distal tip  140  may include a shape or structure that may make it less traumatic to tissue. For example, the distal tip  140  may have a distal surface, such as a tissue contacting surface, that is that is rounded or includes a curvature configured to be more atraumatic to tissue. 
     In some embodiments, all or a portion of the distal holding section  108  may include an inner surface that may be configured to resist getting caught on the fixation mechanism  24 , such as the one or more, or a plurality of hooks  26  on the device  10 . For example, the distal holding section  108  may include an inner layer or coating of harder or more lubricious material that resists force applied by the fixation mechanism  24  onto the inner surface of the distal holding section  108 . For example, the distal holding section  108  may include a multi-layered structure, and an inner layer may be made of a material that is harder than an outer layer. 
     A push member  116  may be disposed (e.g., slidably disposed) within a lumen  152  of the inner tubular member  110 . The push member  116  may be engaged by a user near or at the third hub portion  130 , and extend through a lumen  152  of the inner tubular member  110  and into the distal holding section  108 . A distal portion  118  of the push member  116  may be capable of engaging the device  10 , and the push member  116  may be used to “push” the device  10  out from distal holding section  108  so as to deploy and anchor device  10  within a target region (e.g., a region of the heart such as the right ventricle). 
     In order to more specifically place or steer the delivery device  100  to a position adjacent to the intended target, the delivery device  100  may be configured to be deflectable or articulable or steerable. Referring to  FIG.  2   , for example, the outer tubular member  102  and/or inner tubular member  110  may include one or more articulation or deflection mechanism(s) that may allow for the catheter  100 , or portions thereof, to be deflected, articulated, steered and/or controlled in a desired manner. For example, the outer tubular member  102  may include at least a portion thereof that can be selectively bent and/or deflected in a desired or predetermined direction. This may, for example, allow a user to orient the delivery device  100  such that the holding section  108  is in a desirable position or orientation for navigation or delivery of the device  10  to a target location. The outer tubular member  102  may be deflected, for example, along a deflection region. 
     A wide variety of deflection mechanisms may be used. In some example embodiments, deflection may be effected by one or more actuation members, such as pull wire(s) extending between a distal portion of the outer tubular member  102  and an actuation mechanism  122  near the proximal end of the outer tubular member  102 . As such, the one or more pull wires may extend both proximally and distally of the desired deflection or bending region or point. This allows a user to actuate (e.g., “pull”) one or more of the pull wires to apply a compression and/or deflection force to at least a portion of the outer tubular member  102  and thereby deflect or bend the outer tubular member  102  in a desired manner. In addition, in some cases the one or more wires may be stiff enough so that they can also be used to provide a pushing and/or tensioning force on the outer tubular member  102 , for example, to “push” or “straighten” the shaft into a desired position or orientation. 
     In some embodiments, the actuation member takes the form of a continuous wire that is looped through or otherwise coupled to a distal end region of the outer tubular member  102  so as to define a pair of wire sections. Other embodiments are contemplated, however, including embodiments where the actuation member includes one or a plurality of individual wires that are attached, for example, to a metal or metal alloy ring adjacent the distal end region of the outer tubular member  102 . 
     The actuation mechanism  122  may include a desired mechanism that may allow for applying tension (i.e. pulling force), or compression (i.e. pushing force), or both, on the actuation member(s). In some embodiments, the actuation mechanism  122  may include an external rotatable member  124  connected to and rotatable about the longitudinal axis of the handle assembly  120 . The rotatable member  124  may threadingly engage an internal member that is attached to the proximal end of the actuation member(s) or pull wires. When the external rotatable member  124  is rotated in a first rotational direction, the internal member translates in a first longitudinal direction, thereby applying tension to the pull wires, which applies compression force to the shaft, so as to deflect the outer tubular member  102  from an initial position to a deflected position. When the external rotatable member  124  is rotated in a second rotational direction, the internal member translates in a second longitudinal direction, thereby releasing the tension on the pull wires, and allowing the outer tubular member  102  to relax back toward the initial position. Additionally, in some cases, as mentioned above, where the one or more wires may be stiff enough, rotation of the rotatable member  124  in the second rotational direction such that the internal member translates in a second longitudinal direction may apply compression to the wires, such that the wires may apply tension to the outer tubular member  102  and “push” the outer tubular member  102  back toward an initial position, and possibly into additional positions beyond the initial position. 
     The one or more articulation and/or deflection mechanism(s) may also entail the outer tubular member  102  including structure and/or material that may provide for the desired degree and/or location of the deflection when the compressive or tensile forces are applied. For example, the outer tubular member  102  may include one or more sections that include structure and/or material configured to allow the shaft to bend and/or deflect in a certain way when a certain predetermined compressive and/or tensile force is applied. For example, the shaft may include one or more sections that are more flexible than other sections, thereby defining a bending or articulating region or location. Some such regions may include a number of varying or changing flexibility characteristics that may define certain bending shapes when predetermined forces are applied. Such characteristics may be achieved through the selection of materials or structure for different sections of the outer tubular member  102 . 
     In other embodiments, other articulation and/or deflection mechanism(s) are contemplated. For example, all or a portion of the delivery device  100 , such as the outer tubular member  102 , may be made of a shape memory material, such as a shape memory polymer and/or a shape memory metal. Such materials, when stimulated by an actuation mechanism, such as a change in temperature or the application of an electrical current, may change or move from a first shape to a second shape. As such, these material and mechanism may be used to deflect or bend the outer tubular member  102  in a desired manner. Other suitable deflection mechanism(s) that are able to deflect the delivery device  100  may also be used. Such alternative mechanisms may be applied to all other embodiments shown and/or discussed herein, and others, as appropriate. 
     Furthermore, the outer tubular member  102  may include one or more predefined or fixed curved portion(s) along the length thereof. In some cases, such curved sections may be configured to fit with particular anatomies or be configured for better navigation or delivery of the device  10 . Additionally, or alternatively, some such curved sections may be configured to allow the outer tubular member  102  to be predisposed to be bent and/or deflected in a certain direction or configuration when compression and/or tension forces are applied thereto. 
     Returning again to  FIG.  3   , the distal holding section  108  may be affixed to a distal end portion  114  of the inner tubular member  110 . The distal holding section  108  may include a hub portion  136  and a tubular body portion  138 . In some instances, the hub portion  136  may be formed from a metal or metal alloy while the body portion  138  may be formed from a polymeric material, although this is not required. In some instances, a proximal region  143  of the body portion  138  may be heat bonded to a distal end portion  137  of the hub portion  136 , or otherwise affixed. As the body portion  138  is heated, the body portion  138  may reflow into grooves  141  in the distal end portion  137 . The hub portion  136  may include a tapered intermediate region  145  disposed between a proximal end portion  139  and the distal end portion  137 . 
     In some embodiments, the outer tubular member  102  may include a metal ring or tip adjacent the distal end  103  thereof for attaching one or more pull wires thereto. It is contemplated that the outer tubular member  102  may further include a lubricious liner, such as, but not limited to a polytetrafluoroethylene (PTFE) liner. The proximal end portion  139  of the hub portion  136  may extend proximally into the lumen  150  of the outer tubular member  102 . In some instances, an outer surface of the proximal end portion  139  may form an interference fit with an inner surface of the outer tubular member  102 . It is contemplated that the outer surface of the proximal end portion  139  and the inner surface of the outer tubular member  102  may be coupled in a tapered engagement. For example, the distal end  103  of the outer tubular member  102  may flare radially outwards in the distal direction and/or the proximal end portion  139  may taper radially inward in the proximal direction. The two angled surface may engage as the proximal end portion  139  is proximally retracted within the outer tubular member  102 . Other coupling arrangements may be used as desired. 
       FIG.  3 A  illustrates a partial cross-sectional view of an alternative mechanism for coupling the outer tubular member  102   a  to the proximal end  139   a  of the hub portion  136   a . Some components have been removed for clarity. The outer tubular member  102   a  and the hub portion  136   a  may be similar in form and function to the outer tubular member  102  and the hub portion  136  described above. In some instances, the outer tubular member  102   a  and the proximal end portion  139   a  may be coupled through a threaded engagement. For example, the outer tubular member  102   a  may include a first helical flange or threaded portion  125   a  and the proximal end portion  139   a  may include a second helical flange or threaded portion  127   a  configured to mate with and/or threadably engage the helical flange or threaded portion  125   a  on the outer tubular member  102   a . It is contemplated that the outer tubular member  102   a  and/or the hub portion  136   a  may be rotated in a first direction causing helical flanges or threaded portions  125   a ,  127   a  to engage. Rotation of the outer tubular member  102   a  and/or the hub portion  136   a  in a second direction opposite the first direction may cause the helical flanges or threaded portions  125   a ,  127   a  to disengage. 
       FIG.  3 B  illustrates a partial cross-sectional view of an alternative mechanism for coupling the outer tubular member  102   b  to the proximal end  139   b  of the hub portion  136   b . The outer tubular member  102   b  and the hub portion  136   b  may be similar in form and function to the outer tubular member  102  and the hub portion  136  described above. The coupling arrangement may include a snap lock, a tongue and groove type lock, a mating detent and groove or other features configured to engage a corresponding feature on the outer tubular member  102   b  and/or the proximal end portion  139   b . For example, the outer tubular member  102   b  may include a groove or recess  121   b  disposed in an inner wall thereof. The proximal end  139   b  may include a protrusion, bump, or other extending feature  123   b  configured to mate or engage with the recess  121   b  in the outer tubular member  102   b . It is contemplated that the protrusion  123   b  and the groove  121   b  may be disengaged through application of an external force (e.g., axial force) such as proximal retraction of the outer tubular member  102   b  and/or distal actuation of the hub portion  136   b.    
       FIG.  3 C  illustrates a perspective view of another alternative mechanism for coupling the outer tubular member  102   c  to the proximal end  139   c  of the hub portion  136   c . The outer tubular member  102   c  and the hub portion  136   c  may be similar in form and function to the outer tubular member  102  and the hub portion  136  described above. In some embodiments, the outer tubular member  102   c  and the proximal end portion  139   c  may be coupled through a bayonet style locking feature. It is contemplated that a generally “L” shaped groove  190   c  may be formed in the proximal end  139   c  of the hub portion  136   c . In some instances, the outer tubular member  102   c  may include a protrusion  188   c  extending radially inward from an inner surface of the outer tubular member  102   c . The “L” shaped groove  190   c  and the protrusion  188   c  may be configured to releasably engage one another in a manner similar the locking mechanism  132  described with respect to  FIGS.  6 A- 6 E  such that the outer tubular member  102   c  and the proximal end  139   c  of the hub portion  136   c  may be releasably coupled. Alternatively, a generally “L” shaped groove may be formed in the distal end of the outer tubular member  102   c  and the proximal end  139   c  of the hub portion  136   c  may include a protrusion extending radially outward therefrom for mating engagement with the groove. 
     It is contemplated that as the outer tubular member  102  is bent to navigate the implantable device  10  to the desired location, the proximal end portion  139  may advance distally and disengage from the inner surface of the outer tubular member  102  creating a kink point or weakened region adjacent to the bonding region  146 . Proximally retracting the inner tubular member  110  to bring the intermediate region  145  into contact with the outer tubular member  102  at contact point  148  and/or bringing the proximal end portion  139  into the outer tubular member  102  and fixing the inner tubular member  110  in this configuration may help prevent migration of the distal holding section  108  during navigation of the device  100  to the desired location. Such a configuration may also place the inner tubular member  110  in tension while the distal holding section  108  applies a compression force on the outer tubular member  102 , as will be discussed in more detail below. As discussed above, a locking mechanism  132  in the handle assembly  120  may be utilized to releasably maintain the outer tubular member  102  and the inner tubular member  110  in a desired orientation. 
       FIG.  4    illustrates a cross-sectional view of the handle assembly  120  of the delivery device. As discussed above, the handle assembly  120  may include a first hub portion  126  attached to the proximal end section  104  of the outer tubular member  102 , a second hub portion  128  attached to a proximal end section of the inner tubular member  110 , and a third hub portion  130  attached to a proximal end section of a push member  116 . Each of the first hub portion  126 , the second hub portion  128 , and the third hub portion  130  may be slidable and rotatable relative to each other such that the outer tubular member  102 , inner tubular member  110 , and push member  116  may be individually actuated. 
     The push member  116  may extend distally from a proximal end  117 . The proximal end  117  of the push member  116  may be positioned within or adjacent to a valve member  113 . The valve member  113  may be in fluid communication with a lumen  154  of the push member  116 . The lumen  154  may extend from the proximal end  117  to the distal portion ix)  118  for delivering fluids, such as, but not limited to, a contrast and/or flushing fluid to the cavity  142  of the distal holding section  108 . In some instances, the push member  116  may be coupled or affixed to the third hub portion  130  adjacent the proximal end  117  of the push member  116 , although this is not required. It is contemplated that the push member  116  may be affixed to the third hub portion  130  at any longitudinal location desired. In some instances, a tether (not explicitly shown) for securing the implantable device  10  to the distal portion  118  of the push member  116  may be disposed within the lumen  154  and may exit the device  100  through valve member  113 , although this is not required. 
     The inner tubular member  110  may extend distally from a proximal end  112 . The proximal end  112  of the inner tubular member  110  may be positioned within the second hub portion  128 . The inner tubular member  110  may include a lumen  152  extending from the proximal end  112  to a distal end of the inner tubular member  110 . The push member  116  may be slidably disposed within the lumen  152  of the inner tubular member  110 . In some instances, the inner tubular member  110  may be coupled or affixed to the second hub portion  128  adjacent the proximal end  112  of the push inner tubular member  110 , although this is not required. It is contemplated that the inner tubular member  110  may be affixed to the second hub portion  128  at any longitudinal location desired. 
     The outer tubular member  102  may extend distally from a proximal end  105 . The proximal end  105  of the outer tubular member  102  may be positioned within the first hub portion  126 . The outer tubular member  102  may include a lumen  150  extending from the proximal end  105  to a distal end  103  of the outer tubular member  102 . The inner tubular member  110  may be slidably disposed within the lumen  150  of the outer tubular member  102 . In some instances, the outer tubular member  102  may be coupled or affixed to the first hub portion  126  adjacent the proximal end  105  of the outer tubular member  102 , although this is not required. It is contemplated that the outer tubular member  102  may be affixed to the first hub portion  126  at any longitudinal location desired. 
     In some instances, the first hub portion  126  may include a retaining ring  158  positioned adjacent to a proximal end of the first hub portion  126 . In some instances, the retaining ring  158  may be rotatable about a longitudinal axis of the handle assembly  120 . It is further contemplated that the retaining ring  158  may include locking features configured to engage with other locking features of the locking mechanism  132 . In some instances, the second hub portion  128  may include a retaining ring  164  positioned adjacent to a proximal end of the second hub portion  128 . In some instances, the retaining ring  164  may be rotatable about a longitudinal axis of the handle assembly  120 . It is further contemplated that the retaining ring  164  may include locking features configured to engage with other locking features of the locking mechanism  134 . 
       FIG.  5    illustrates a partial perspective view of handle assembly  120  with portions of the first hub portion  126  removed to more clearly illustrate features of the first locking mechanism  132 , which may releasably couple the first hub portion and the second hub portion and/or the outer tubular member  102  and the inner tubular member  110 . In some instances, the locking mechanism  132  may be a bayonet style locking feature. It is contemplated that a generally “L” shaped groove  156  may be formed in the second hub portion  128  adjacent a distal end  129  of the second hub portion  128 . In some instances, the retaining ring  158  may include a protrusion  162  (schematically represented in  FIGS.  6 A- 6 E ) extending radially inward from an inner surface of the retaining ring  158 . The retaining ring  158 , and the first hub portion  126 , may have an inner diameter generally larger than an outer diameter of the second hub portion  128  such that the second hub portion  128  can be proximally retracted  168  and distally advanced  170  within a lumen of the first hub portion  126 . 
     Referring additionally to  FIGS.  6 A- 6 E , when a user desires to couple the outer tubular member  102  and the inner tubular member  110 , the second hub portion  128  may be rotated  172  relative to the first hub portion  126  about the longitudinal axis of the handle assembly  120  to align the protrusion  162  with a first or vertical portion  157  of the groove  156  as shown in  FIG.  6 A . The use of “vertical” and “horizontal” are not intended to be limiting rather to provide relative movements of interacting components. In alternative embodiments, the first hub portion  126 , or components thereof, may be rotated relative to the second hub portion  128 . The second hub portion  128  may be proximally retracted  168  to advance the protrusion  162  further into the groove  156  as indicated at arrow  174 . Once the protrusion  162  is positioned distal of protruding region  176 , the second hub portion  128  may be rotated in a first direction to advance the protrusion  162  along a second or horizontal portion  159  of the groove  156  generally orthogonal to the vertical portion  157  towards a dip, recess, or serif  160  positioned at an end of the horizontal portion  159  as shown at arrow  178  in  FIG.  6 B . A wall  180  may provide a stopping mechanism adjacent to the serif  160 . Once the protrusion  162  has engaged the stopping mechanism  180 , the second hub portion  128  may be advanced distally  170  to secure the protrusion  162  within the serif  160 , as shown in  FIG.  6 C . The serif  160  may help prevent accidental rotation of the retaining ring  158  and thus accidental uncoupling of the outer tubular member  102  and the inner tubular member  110 . 
     It is contemplated that in an unbiased state or unlocked configuration, (e.g. when the outer tubular member  102  and the inner tubular member  110  are not coupled via the locking mechanism  132 ) the distal end  129  of the second hub portion  128  may extend distally beyond the protrusion  162  and the retaining ring  158 . Proximally retracting the second hub portion  128  (secured to the inner tubular member  110 ) relative to the first hub portion  126  (secured to the outer tubular member  102 ) to engage the protrusion  162  and the serif  160  may place the inner tubular member  110  in tension. In some instances, a tensile force in the range of about 1-3 pounds-force (about 4.4-13.3 Newtons) or approximately less than 2 pounds-force (approximately less than 8.9 Newtons) may be applied to the inner tubular member  110 . As the inner tubular member  110  (e.g., the proximal end of the inner tubular member  110 ) is proximally retracted along with the second hub portion  128 , the hub portion  136  of the distal holding section  108  may apply a proximal force on the distal end of the outer tubular member  102  thus placing the outer tubular member  102  under compression. This configuration may allow the multiple shaft delivery device  100  to behave like a single shaft delivery device. It is contemplated that placing the inner tubular member  110  in tension may account for a shorter path length of the outer tubular member  102  at bends in the delivery device  100 . For example, as the outer tubular member  102  curves a first side of the tube wall may have a first arc radius and a second side of the tube wall, opposite first side of the tube wall, may have a second arc radius smaller than the first arc radius. In an uncoupled configuration, the inner tubular member  110  may contact the first side of the tube wall of the outer tubular member  102 . This may place a biasing force against the outer tubular member  102  in a direction other than the desired curve. In a coupled arrangement with the inner tubular member  110  in tension, the position of the inner tubular member  110  within the lumen  150  of the outer tubular member  102  may be brought closer the second side of the tube wall. This may facilitate steering of the device  100  to the desired location by reducing the forces applied on the outer tubular member  102 . Additionally, actuation of either of the outer tubular member  102  or the inner tubular member  110  may result in the actuation of both the outer tubular member  102  and the inner tubular member  110 . It is further contemplated that when the inner tubular member  110  and the outer tubular member  102  are in a coupled configuration, the distal holding section  108  may not move distally out of engagement with the outer tubular member  102 . 
     When a user desires to uncouple the outer tubular member  102  and the inner tubular member  110 , the second hub portion  128  may be distally advanced  170  to disengage the protrusion  162  from the serif  160 . The second hub portion  128  may then be rotated  172  relative to the first hub portion  126  about the longitudinal axis of the handle assembly  120  in a direction opposite to the direction used to couple the outer tubular member  102  and the inner tubular member  110  as indicated at arrow  182  in  FIG.  6 D . The second hub portion  128  may be rotated in a second direction, generally opposite to the first direction, to advance the protrusion  162  along the horizontal portion  159  of the groove  156  towards the vertical portion  157  as shown at arrow  182  in  FIG.  6 D . A wall  184  may provide a stopping mechanism adjacent to the vertical portion  157 . Once the protrusion  162  has engaged the stopping mechanism  184 , the second hub portion  128  may be advanced distally  170  to disengage the protrusion  162  from the mating groove  156 , as shown at arrow  186  in  FIG.  6 E . It is further contemplated that the outer surface of the retaining ring  158 , the first hub portion  126 , and/or the second hub portion  128  may be provided with visual markings to assist the user locking and/or unlocking the locking mechanism  132 . It is further contemplated that in some instances, the “L” shaped groove may be positioned on the retaining ring  158  or first hub portion  126  and the protrusion  162  may be positioned on the second hub portion  128 . Furthermore, while the first locking mechanism  132  has been described as a bayonet style locking mechanism other locking mechanisms capable of releasably securing the outer tubular member  102  and the inner tubular member  110  are contemplated. 
     For example, the locking mechanism  132  may be formed in a similar manner to a quick connect locking mechanism commonly used in plumbing applications. A quick connect locking mechanism may utilize an o-ring and a compression fit to maintain a fluid tight seal. A rotating locking ring may maintain the quick connect locking mechanism in a locked configuration. In other embodiments, the locking mechanism  132  may include a threaded engagement similar to the threaded engagement described above with respect to  FIG.  3 A . For example, the retaining ring  158  or other portion of the first hub portion  126  may include a first threaded region and the second hub portion  128  may include a second threaded region configured to mate with and/or threadably engage the threaded region on the retaining ring  158  or other portion of the first hub portion  126 . Thus rotation of the retaining ring  158  and/or other portion of the first hub portion  126  relative to the second hub portion  128  may place the inner tubular member  110  in tension while placing the outer tubular member  102  in compression. In yet other embodiments, the locking mechanism  132  may include a snap lock, a tongue and groove type lock, a mating detent and groove or other features configured to engage a corresponding feature on the retaining ring  158  and/or second hub portion  128  similar to the coupling arrangement described above with respect to  FIG.  3 B . 
       FIG.  7    illustrates another partial perspective view of handle assembly  120  with portions of the second hub portion  128  removed to more clearly illustrate features of the second locking mechanism  134 , which may be used to releasably couple the inner tubular member  110  and the push member  116 . In some instances, the locking mechanism  134  may be a bayonet style locking feature. It is contemplated that a generally “L” shaped groove  166  may be formed in the third hub portion  130  adjacent a distal end  131  of the third hub portion  130 . In some instances, the retaining ring  164  (not explicitly shown in  FIG.  7   ) may include a protrusion, which may be similar in form and function to the protrusion  162  described with respect to  FIGS.  5  and  6 A- 6 E , extending radially inward from an inner surface of the retaining ring  164 . The retaining ring  164 , and the second hub portion  128 , may have an inner diameter generally larger than an outer diameter of the third hub portion  130  such that the third hub portion  130  can be proximally retracted  168  and distally advanced  170  within a lumen of the second hub portion  128 . It is contemplated that the second locking mechanism  134  may function in a similar manner to the first locking mechanism  132  described above. 
     When a user desires to couple the inner tubular member  110  and the push member  116 , the third hub portion  130  may be rotated  172  relative to the second hub portion  128  in a first direction about the longitudinal axis of the handle assembly  120  to align the protrusion with a first or vertical portion  165  of the groove  166 . The use of “vertical” and “horizontal” are not intended to be limiting rather to provide relative movements of interacting components. In alternative embodiments, the second hub portion  128 , or components thereof, may be rotated relative to the third hub portion  128 . The third hub portion  130  may be proximally retracted  168  to advance the protrusion further into the groove  166 . Once the protrusion is positioned distal of protruding region  171 , the third hub portion  130  may be rotated to advance the protrusion along a second or horizontal portion  167  of the groove  166  generally orthogonal to the vertical portion  165  towards a dip or serif  169  positioned at an end of the horizontal portion  167 . A wall  173  may provide a stopping mechanism adjacent to the serif  169 . Once the protrusion has engaged the stopping mechanism  173 , the third hub portion  130  may be advanced distally  170  to secure the protrusion within the serif  169 . The serif  169  may help prevent accidental rotation of the retaining ring  164  and thus accidental uncoupling of the inner tubular member  110  and the push member  116 . 
     It is contemplated that in an unbiased state or unlocked configuration, (e.g. when the inner tubular member  110  and the push member  116  are not coupled via the locking mechanism  134 ) the distal end  131  of the third hub portion  130  may extend distally beyond the protrusion and the retaining ring  164 . Proximally retracting the third hub portion  130  (secured to the push member  116 ) relative to the second hub portion  128  (secured to the inner tubular member  110 ) to engage the protrusion and the serif  169  may place the push member  116  in tension. It is contemplated that placing the push member  116  in tension may account for a shorter path length at bends in the delivery device  100 . 
     When a user desires to uncouple the inner tubular member  110  and the push member  116 , the third hub portion  130  may be distally advanced  170  to disengage the protrusion from the serif  169 . The third hub portion  130  may then be rotated  172  relative to the second hub portion  128  in a second direction, generally opposite the first direction, about the longitudinal axis of the handle assembly  120 . The third hub portion  130  may be rotated to advance the protrusion along the horizontal portion  167  of the groove  166  towards the vertical portion  165 . A wall  175  may provide a stopping mechanism adjacent to the vertical portion  165 . Once the protrusion has engaged the stopping mechanism  175 , the third hub portion  130  may be advanced distally  170  to disengage the protrusion from the mating groove  166 . It is further contemplated that the outer surface of the retaining ring  164 , second hub portion  128 , and/or the third hub portion  130  may be provided with visual markings to assist the user locking and/or unlocking the locking mechanism  134 . It is further contemplated that in some instances, the “L” shaped groove may be positioned on the retaining ring  164  or second hub portion  128  and the protrusion may be positioned on the third hub portion  130 . Furthermore, while the second locking mechanism  134  has been described as a bayonet style locking mechanism other locking mechanisms capable of releasably securing the inner tubular member  110  and the push member  116  are contemplated. 
     For example, the locking mechanism  134  may be formed in a similar manner to a quick connect locking mechanism commonly used in plumbing applications. A quick connect locking mechanism may utilize an o-ring and a compression fit to maintain a fluid tight seal. A rotating locking ring may maintain the quick connect locking mechanism in a locked configuration. In other embodiments, the locking mechanism  134  may include a threaded engagement similar to the threaded engagement described above with respect to  FIG.  3 A . For example, the retaining ring  164  or other portion of the second hub portion  128  may include a first threaded region and the third hub portion  130  may include a second threaded region configured to mate with and/or threadably engage the threaded region on the retaining ring  164  or other portion of the second hub portion  128 . Thus rotation of the retaining ring  164  and/or other portion of the second hub portion  128  relative to the third hub portion  130  may place the push member  116  in tension. In yet other embodiments, the locking mechanism  134  may include a snap lock, a tongue and groove type lock, a mating detent and groove or other features configured to engage a corresponding feature on the retaining ring  164  and/or third hub portion  130  similar to the coupling arrangement described above with respect to  FIG.  3 B . 
     The materials that can be used for the various components of the delivery devices, such as delivery device  100  (and/or other delivery structures disclosed herein) and the various members disclosed herein may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference the delivery device  100  and components of thereof. However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to other similar delivery systems and/or components of delivery systems or devices disclosed herein. 
     The delivery device  100  and/or other components of delivery system may be made from a metal, metal alloy, polymer (some examples of which are disclosed below), a metal-polymer composite, ceramics, combinations thereof, and the like, or other suitable material. Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane (for example, Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS  50 A), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. In some embodiments the polymer can be blended with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6 percent LCP. 
     Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic and/or super-elastic nitinol; other nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g., UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like); platinum enriched stainless steel; titanium; combinations thereof; and the like; or any other suitable material. 
     As alluded to herein, within the family of commercially available nickel-titanium or nitinol alloys, is a category designated “linear elastic” or “non-super-elastic” which, although may be similar in chemistry to conventional shape memory and super elastic varieties, may exhibit distinct and useful mechanical properties. Linear elastic and/or non-super-elastic nitinol may be distinguished from super elastic nitinol in that the linear elastic and/or non-super-elastic nitinol does not display a substantial “superelastic plateau” or “flag region” in its stress/strain curve like super elastic nitinol does. Instead, in the linear elastic and/or non-super-elastic nitinol, as recoverable strain increases, the stress continues to increase in a substantially linear, or a somewhat, but not necessarily entirely linear relationship until plastic deformation begins or at least in a relationship that is more linear that the super elastic plateau and/or flag region that may be seen with super elastic nitinol. Thus, for the purposes of this disclosure linear elastic and/or non-super-elastic nitinol may also be termed “substantially” linear elastic and/or non-super-elastic nitinol. 
     In some cases, linear elastic and/or non-super-elastic nitinol may also be distinguishable from super elastic nitinol in that linear elastic and/or non-super-elastic nitinol may accept up to about 2-5% strain while remaining substantially elastic (e.g., before plastically deforming) whereas super elastic nitinol may accept up to about 8% strain before plastically deforming. Both of these materials can be distinguished from other linear elastic materials such as stainless steel (that can also can be distinguished based on its composition), which may accept only about 0.2 to 0.44 percent strain before plastically deforming. 
     In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by differential scanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA) analysis over a large temperature range. For example, in some embodiments, there may be no martensite/austenite phase changes detectable by DSC and DMTA analysis in the range of about −60 degrees Celsius (° C.) to about 120° C. in the linear elastic and/or non-super-elastic nickel-titanium alloy. The mechanical bending properties of such material may therefore be generally inert to the effect of temperature over this very broad range of temperature. In some embodiments, the mechanical bending properties of the linear elastic and/or non-super-elastic nickel-titanium alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature, for example, in that they do not display a super-elastic plateau and/or flag region. In other words, across a broad temperature range, the linear elastic and/or non-super-elastic nickel-titanium alloy maintains its linear elastic and/or non-super-elastic characteristics and/or properties. 
     In some embodiments, the linear elastic and/or non-super-elastic nickel-titanium alloy may be in the range of about 50 to about 60 weight percent nickel, with the remainder being essentially titanium. In some embodiments, the composition is in the range of about 54 to about 57 weight percent nickel. One example of a suitable nickel-titanium alloy is FHP-NT alloy commercially available from Furukawa Techno Material Co. of Kanagawa, Japan. Some examples of nickel titanium alloys are disclosed in U.S. Pat. Nos. 5,238,004 and 6,508,803, which are incorporated herein by reference. Other suitable materials may include ULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available from Toyota). In some other embodiments, a superelastic alloy, for example a superelastic nitinol can be used to achieve desired properties. 
     In at least some embodiments, portions or all of the delivery device  100  and/or other components of delivery system may be doped with, made of, or otherwise include a radiopaque material. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user of the delivery device  100  in determining its location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymer material loaded with a radiopaque filler, and the like. Additionally, other radiopaque marker bands and/or coils may also be incorporated into the design of the delivery device  100  to achieve the same result. 
     In some embodiments, a degree of Magnetic Resonance Imaging (MRI) compatibility is imparted into the delivery device  100 . For example, delivery device  100  or portions or components thereof, may be made of a material that does not substantially distort the image and create substantial artifacts (i.e., gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they may create artifacts in an MRI image. The delivery device  100 , or portions thereof, may also include and/or be made from a material that the MRI machine can image. Some materials that exhibit these characteristics include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as MP35-N® and the like), nitinol, and the like, and others. 
     It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the disclosure. This may include, to the extent that it is appropriate, the use of any of the features of one example embodiment being used in other embodiments. The invention&#39;s scope is, of course, defined in the language in which the appended claims are expressed.