Abstract:
This disclosure pertains, inter alia, to scaffold loading and delivery devices, assemblies, systems and methods of using the same.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/273,188 filed Dec. 30, 2015 and entitled Scaffold Loading and Delivery Systems which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    This disclosure pertains, inter alia, to scaffold loading and delivery devices, assemblies, systems and methods of using the same. 
       BACKGROUND 
       [0003]    A variety of medical conditions are treatable by the implantation of expandable devices into natural body lumens. For example, it is commonplace to implant stents into the vasculature of diseased patients to mitigate the risks associated with vessel stenosis. Other examples of conventional tubular medical implants include woven grafts and stent-grafts that are used to span vascular aneurysms, expandable devices that are used to bypass strictures in the ureter and urethra, and stents that are used in the peripheral vasculature, prostate, sinus, airways, and esophagus, among others. 
         [0004]    While biostable and biodegradable polymeric stents have been proposed to address the limitations of metallic stents, including potential issues with thrombosis, chronic injury, and vascular remodeling, their use has been limited by the fact that polymeric stents may undergo stress relaxation if left in a crimped delivery configuration for an extended period of time, such as during shipping and storage. 
         [0005]    There is a continuing need for devices and systems that offer the possibility of loading polymeric tubular implants into a delivery system by a healthcare professional just prior to implantation, thereby avoiding the possibility that the implant undergo stress relaxation during shipping and/or storage in a loaded or crimped configuration. 
       SUMMARY 
       [0006]    In various aspects, the present disclosure provides a loading system that includes (a) a delivery catheter, (b) a loading assembly that includes (i) a funnel assembly that includes a tapered funnel structure, and optionally, a pin lift, a clamp and/or a body portion and (ii) a loading aid assembly that includes a receptacle, a plurality of loading pins and, optionally, a self-expanding scaffold. When a self-expanding scaffold is provided within the loading aid assembly, the self-expanding scaffold may be held within the receptacle via the loading pins and may be used to longitudinally guide the self-expanding scaffold into the tapered funnel structure of the funnel assembly, which provides a funnel shape for crimping the scaffold. In various embodiments, the optional clamp may be used to secure the funnel assembly to the delivery catheter and/or the optional pin lift may be used to retract the loading pins from the scaffold. In various embodiments, the optional body portion may be used to maintain the clamp, tapered funnel and pin lift in a single structure. 
         [0007]    In various aspects, the present disclosure provides a loading assembly that comprises: (a) a funnel assembly comprising a tapered funnel structure having a distal end and a proximal end and comprising (i) a loading lumen having a loading axis, an open distal end, an open proximal end, and at least one tapered region having a distal end with a first diameter and a proximal end with a second diameter that is smaller than the first diameter and (ii) a slotted wall surrounding the loading lumen that has a plurality of longitudinal slots formed therein, the slots having an open distal end; and (b) a loading aid assembly comprising (i) a receptacle comprising a receptacle wall, a receptacle lumen having a least one open receptacle lumen end and a receptacle axis, (ii) a scaffold comprising a scaffold wall and having a scaffold axis, a proximal scaffold end, a distal scaffold end, an inner luminal surface and an outer abluminal surface, (iii) a plurality of loading pins comprising loading pin shafts that extend from the receptacle wall, into the receptacle lumen and through the scaffold wall, the pins holding the scaffold within the receptacle lumen in a position in which the scaffold axis is coaxial with the receptacle axis. The loading aid assembly is configured to receive the distal end of the tapered funnel structure within the receptacle lumen via the open receptacle lumen end, such that the scaffold is at least partially positioned in the loading lumen, such that at least a portion of the tapered funnel structure wall is positioned between the outer abluminal surface of the stent and the inner luminal surface of the receptacle wall, such that the loading pins are positioned within the longitudinal slots of the tapered funnel structure, and such that longitudinal movement of the loading aid assembly in a proximal direction relative to the funnel assembly results in proximal longitudinal movement of the loading pins within the slots of the tapered funnel structure and proximal longitudinal movement of at least the proximal scaffold end into the tapered region thereby reducing at least a portion of the diameter of the same. 
         [0008]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, the loading pins may comprise (a) a loading pin shaft that extends through an aperture in the receptacle wall and into the receptacle lumen and (b) an enlarged portion positioned on a side of the receptacle wall opposite the receptacle lumen, the enlarged portion having a width that is greater than a width of the aperture. In certain of these embodiments, the receptacle may comprise first and second walls separated by a gap and wherein the enlarged portions of the pins are positioned in the gap between the walls. 
         [0009]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, the loading aid assembly may further comprise springs that bias the loading pins toward the receptacle axis. 
         [0010]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, the loading assembly may comprise a stop that limits the proximal longitudinal movement of the loading pin shafts within the slots of the tapered funnel structure. In certain of these embodiments, removal of the loading pin shafts from the scaffold wall and the slots allows additional longitudinal movement of the loading aid assembly in a proximal direction relative to the funnel assembly, in which case the receptacle may be configured to compress and close the slots of the tapered funnel structure upon the additional longitudinal movement, if desired. 
         [0011]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, the loading assembly may comprise a pin lift having a radially tapered surface, such that relative longitudinal movement between the radially tapered surface of the pin lift and the loading pins may engage the loading pins and move the loading pins radially away from the receptacle axis. In certain of these embodiments, the pin lift may be part of the funnel assembly and distal longitudinal movement of the radially tapered surface of the pin lift relative to the loading pins engages the loading pins and moves the loading pins radially away from the receptacle axis. Alternatively or in addition, the loading pins may comprise (a) a loading pin shaft that extends through an aperture in the receptacle wall and into the receptacle lumen and (b) an enlarged portion positioned on a side of the receptacle wall opposite the receptacle lumen and having a width that is greater than a width of the aperture, such that distal longitudinal movement of the pin lift relative to the loading pins causes the tapered surface of the pin lift to engage the enlarged portions of the loading pins and move the loading pins radially away from the receptacle axis. For this purpose, the pin lift may comprise, for example, a plurality of tapered projections each pair forming a slot therebetween which is configured to receive the loading pin shafts. 
         [0012]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, the funnel assembly may further comprise a clamp for positioning a delivery sheath of a catheter in a position such that the delivery sheath is positioned to receive the scaffold from the loading lumen. 
         [0013]    In some aspects, the disclosure provides a loading system that comprises (a) a loading assembly in accordance with any of the above aspects and embodiments, and (b) a catheter that comprises: (i) an outer sheath comprising an outer sheath lumen and having a proximal outer sheath end and a distal outer sheath end and (ii) an inner member having an inner member proximal end and an inner member distal end and comprising an elongate shaft and an enlarged diameter portion near the inner member distal end, at least a portion of the elongate inner member being disposed within the outer sheath. 
         [0014]    In some embodiments, the outer sheath and the inner member of the catheter are positioned relative to the tapered funnel structure such that the distal end of the outer sheath lumen is in communication with the loading lumen and such that the elongate inner member extends beyond the distal end of the outer sheath and at least partially though the tapered region of the loading lumen. 
         [0015]    In some embodiments, proximal longitudinal movement of the loading aid assembly relative to the funnel assembly proceeds to a point where the loading pins reach a stop, resulting in a reduction in diameter of at least a proximal portion of the scaffold and in the scaffold being disposed around the enlarged diameter portion of the inner elongate member. In certain instances, the loading system may include a handle that independently proximally retracts the inner elongate member and outer sheath. In certain instances, removal of the loading pin shafts from the slots and further proximal longitudinal movement of the loading aid assembly beyond the point where the loading pins reach a stop, may cause compression of the tapered funnel structure such that the slots close, such that the inner diameter of the tapered region is reduced, and such that proximal movement of the inner elongate member causes the enlarged diameter portion of the inner elongate member to engage the scaffold and draw the scaffold into outer sheath. For example, an inner luminal surface of the receptacle wall may be tapered for this purpose, such that the slots close and the diameter of the tapered region is reduced upon the further proximal longitudinal movement of the loading aid assembly. 
         [0016]    In other aspects, the disclosure provides a catheter that comprises: (a) an outer sheath comprising an outer sheath lumen and having a proximal outer sheath end and a distal outer sheath end and (b) an inner member having an inner member proximal end and an inner member distal end and comprising an elongate shaft and an enlarged diameter portion near the inner member distal end that comprises a hub and a plurality of radial projections extending from the hub, the inner member being disposable within the outer sheath. 
         [0017]    In some embodiments, the inner member may further comprise a braid reinforced tube, a wound wire coil and a tapered distal tip. 
         [0018]    Alternatively or in addition, the outer sheath may comprises a proximal shaft and an outer distal capsule. 
         [0019]    In other aspects, the disclosure provides a method of crimping a tubular self-expanding scaffold using the loading assembly in accordance with any of the above aspects and embodiments, the method comprising: (a) joining the loading aid assembly with the funnel assembly, such that the distal end of the tapered funnel structure is positioned within the receptacle lumen, such that the scaffold is at least partially positioned in the loading lumen, such that at least a portion of the tapered funnel structure wall is positioned between the outer abluminal surface of the stent and the inner luminal surface of the receptacle wall, and such that the loading pins are positioned within the longitudinal slots of the tapered funnel structure; and (b) generating longitudinal movement of the loading aid assembly in a proximal direction relative to the funnel assembly such that the loading pins undergo proximal longitudinal movement within the slots of the tapered funnel structure and such that at least the proximal scaffold end undergoes proximal longitudinal movement into the tapered region, thereby reducing at least a portion of the diameter of the scaffold. 
         [0020]    In certain embodiments, the method further comprises removing the loading pin shafts from the scaffold wall and the slots. In certain of these embodiments, the method additionally comprises generating further longitudinal movement of the loading aid assembly in a proximal direction relative to the funnel assembly, wherein an inner luminal surface of the receptacle wall is tapered such that the receptacle compresses and closes the slots of the tapered funnel structure as a result of the further longitudinal movement. 
         [0021]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, the funnel assembly may be attached to a delivery sheath of a catheter such that the delivery sheath is positioned to receive the scaffold from the loading lumen. 
         [0022]    In various embodiments, which may be used in conjunction with any of the preceding aspects and embodiments, (a) the funnel assembly may be attached to a catheter that comprises (i) an outer sheath comprising an outer sheath lumen and having a proximal outer sheath end and a distal outer sheath end and (ii) an inner member having an inner member proximal end and an inner member distal end and comprising an elongate shaft and an enlarged diameter portion near the inner member distal end, at least a portion of the elongate inner member being disposed within the outer sheath, (b) the outer sheath and the inner member may be positioned relative to the tapered funnel structure such that the distal end of the outer sheath lumen is in communication with the loading lumen and such that the elongate inner member extends beyond the distal end of the outer sheath and at least partially though the tapered region of the loading lumen, and (c) the longitudinal movement of the loading aid assembly in a proximal direction relative to the funnel assembly may cause the scaffold to be disposed around the enlarged diameter portion of the inner elongate member and reduce at least a portion of the diameter of the scaffold that is disposed around the inner elongate member into engagement with the enlarged diameter portion of the inner elongate member. In such embodiments, the method may further comprise proximally moving the inner elongate member relative to the outer sheath, thereby drawing the scaffold into the outer sheath lumen. 
         [0023]    The above and other aspects and embodiments and of the present disclosure will become immediately apparent to those of ordinary skill in the art upon review of the detailed description and claims to follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIGS. 1A and 1B  are schematic cutaway views in line format and shaded format, respectively, of a delivery system in accordance with the present disclosure at a first stage in a scaffold loading process. 
           [0025]      FIG. 1C  is a schematic illustration of a scaffold. 
           [0026]      FIGS. 2A and 2B  are schematic cutaway views in line format and shaded format, respectively, of a delivery system in accordance with the present disclosure at a second stage in a scaffold loading process. 
           [0027]      FIGS. 3A and 3B  are schematic cutaway views in line format and shaded format, respectively, of a delivery system in accordance with the present disclosure at a third stage in a scaffold loading process. 
           [0028]      FIGS. 4A and 4B  are schematic cutaway views in line format and shaded format, respectively, of a delivery system in accordance with the present disclosure at a fourth stage in a scaffold loading process. 
           [0029]      FIG. 5  is a schematic cutaway view of a loading aid assembly in accordance with the present disclosure. 
           [0030]      FIG. 6A  is a schematic side view of a pin assembly in accordance with the present disclosure. 
           [0031]      FIG. 6B  is a schematic perspective view of one half of an inner collar in accordance with the present disclosure. 
           [0032]      FIG. 6C  is a schematic perspective view of one half of an outer housing in accordance with the present disclosure. 
           [0033]      FIG. 7  is a schematic perspective view of a funnel assembly in accordance with the present disclosure. 
           [0034]      FIG. 8A  is a schematic cutaway perspective view a loading system in accordance with the present disclosure. 
           [0035]      FIG. 8B  is a schematic perspective view of one half of pin lift in accordance with the present disclosure. 
           [0036]      FIG. 8C  is a schematic perspective view of one quarter of a tapered funnel structure in accordance with the present disclosure. 
           [0037]      FIG. 9A  is a schematic perspective view illustrating a catheter in accordance with the present disclosure. 
           [0038]      FIG. 9B  is a schematic perspective view illustrating a scaffold lock in accordance with the present disclosure. 
           [0039]      FIG. 10  is a schematic perspective view of a loading system in accordance with the present disclosure. 
           [0040]      FIG. 11  is a schematic cutaway view of a delivery catheter handle. 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    The devices, assemblies and systems described herein are useful for loading, delivery and deployment of self-expanding scaffolds into bodily lumens. 
         [0042]    The implantable scaffolds loaded and delivered by the delivery systems of the present disclosure are generally tubular devices, which are self-expanding devices in various embodiments. As used herein, “device,” “scaffold,” “stent” and “implant” may be used synonymously. Also as used herein, “self-expanding” is intended to include devices that are crimped to a reduced delivery configuration for delivery into the body, and thereafter tend to expand to a larger suitable configuration once released from the delivery configuration. As used herein “strands” and “filaments” may be used interchangeably and include single fiber strands and filaments (also referred to as monofilaments) and multi-fiber strands and filaments. As used herein a “sheath,” “tube,” “hollow member,” “catheter” and “tubular member” may be used synonymously. 
         [0043]    Scaffolds for use in conjunction with the present disclosure are typically tubular devices which may be of various sizes, including a variety of diameters and lengths, and which may be used for a variety of applications. Various scaffold embodiments of the present disclosure are self-expanding in that they are manufactured at a first diameter, subsequently reduced or “crimped” to a second reduced diameter for placement within a delivery catheter, and self-expand towards the first diameter when extruded from the delivery catheter at an implantation site. Scaffolds for use in the present disclosure may be formed from a variety of polymeric and non-polymeric materials. Scaffolds for use in the present disclosure may be biodegradable or non-biodegradable, or be a combination of both biodegradable and non-biodegradable materials. In various embodiments, the implantable scaffolds may comprise a generally tubular structure comprising scaffolding material. Scaffolds for use in the present disclosure may be fiber-based or non-fiber-based. In various embodiments, scaffolds for use in the present disclosure are braided scaffolds. 
         [0044]    In one aspect the present disclosure describes loading systems that include (a) a delivery catheter, (b) a loading assembly that includes (i) a funnel assembly that includes a tapered funnel structure, and optionally, a pin lift, a clamp and/or a body portion and (ii) a loading aid assembly that includes a receptacle, a plurality of loading pins and, optionally, a self-expanding scaffold. The loading aid assembly holds the self-expanding scaffold within the receptacle via the loading pins and is used to longitudinally guide the self-expanding scaffold into the tapered funnel structure of the funnel assembly. The funnel assembly is typically attached to the distal end of the delivery catheter. A clamp, such as a roller clamp, can be used to secure the funnel assembly to the delivery catheter, the tapered funnel structure within the funnel assembly provides a funnel shape for crimping the scaffold. Where provided, the pin lift retracts the loading pins from the scaffold, and the main body can be used to maintain the clamp, tapered funnel and pin lift in a single structure. 
         [0045]    With reference now to  FIGS. 1A-1C , a partial schematic cutaway view of loading system in accordance with the present disclosure is shown. The loading system includes (a) a catheter  140 , (a) a funnel assembly that includes a tapered funnel structure  110  and a pin lift  130  (as well as a body portion and a roller clamp as discussed further below) and (c) a loading aid assembly  120  that includes a receptacle  122 , a cylindrical scaffold  200  and a plurality of loading pin assemblies  124   a.    
         [0046]    The tapered funnel structure  110  has a distal end  110   d  and a proximal end (not shown) and includes (i) a plurality of longitudinal slots  110   s  formed therein (the face of slot  110   s  is identified in  FIGS. 1A and 1B ), the slots  110   s  having an open distal end  110   sd  and (ii) a loading lumen  110   l  having a loading axis (coincident with axis  122   a ), a lumen distal end  110   ld , a lumen proximal end  110   lp  and at least one tapered region  110   t  having a tapered region distal end (in this case, corresponding to the distal end  110   ld  of the loading lumen  110   l ) with a first diameter and having a tapered region proximal end  110   tp  with a second diameter that is smaller than the first diameter. 
         [0047]    The loading aid assembly  120  comprises the following: (i) a receptacle  122  having a receptacle axis  122   a  and having a receptacle wall  122   w  and a receptacle lumen  1221  having an open proximal end and, (ii) a cylindrical scaffold  200  comprising (see  FIG. 1C ) a scaffold wall  200   w  and having a scaffold axis  200   a , a proximal scaffold end  200   p , a distal scaffold end  200   d , an inner luminal surface  200   i  and an outer abluminal surface  200   o , (iii) a plurality (four shown) of loading pin assemblies  124   a  comprising enlarged loading pin caps  124   e  and pin shafts  124   p  that extend from the receptacle wall, into the receptacle lumen  1221  and through the scaffold wall  200   w  (e.g., through a diamond-shaped aperture in a braided stent or through a cell of another closed cell stent design, etc.). The loading pin assemblies  124   a  hold the scaffold  200  within the receptacle lumen  1221  and in a position such that the scaffold axis  200   a  is coaxial with the receptacle axis  122   a . In the embodiment shown, the receptacle  122  is formed from two components: an outer housing  122   h  having an outer housing wall  122   hw  and an inner collar  122   c  having an inner collar wall  122   cw . The loading pin shafts  124   p  extend through the inner collar wall  122   cw . The loading pin assemblies  124   a  in the embodiment shown are further provided with loading pin springs  124   s , which are disposed between the housing wall  120   aw  and the enlarged loading pin heads  124   e , bias the pin shafts  124   p  toward the receptacle axis  122   a . Due to the loading pin springs  124   s , the loading pin heads  124   e  are biased against the collar wall  122   cw.    
         [0048]    An additional view of the loading aid assembly  120  is provided in  FIG. 5 , which shows the outer housing  122   h , inner collar  122   c , loading pin assemblies  124   a  and scaffold  200 . In some cases, a loading aid assembly  120  with a preloaded scaffold  200  of this type may be pre-constructed, packaged and sterilized for use by a health care professional. 
         [0049]    Further detail of a loading pin assembly  124   a  is provided in  FIG. 6A , which shows the pin shaft  124   p , enlarged loading pin cap  124   e  and loading pin spring  124   s  of the loading pin assembly  124   a . Further detail of one half of the inner collar  122   c  is shown in the perspective view in  FIG. 6B . Further detail of one half of the outer housing  122   h  is shown in the perspective view in  FIG. 6C . 
         [0050]    Further detail of the catheter  140  provided in  FIGS. 1A and 1B  is provided in  FIG. 9A , which shows an outer sheath  144  that includes a proximal shaft  144   p  and an outer distal capsule  144   d . Thus, in the embodiment shown, the outer sheath  144  is a composite design consisting of outer distal capsule  144   d  for scaffold encapsulation and a smaller diameter outer proximal shaft  144   p . The outer distal capsule  144   d  may include a liner such as a fluoropolymer (e.g., polytetrafluoroethylene) liner for lubricity and a braid reinforced tube for radial strength. The outer proximal shaft  144   p  may include a braid reinforced tube and a tightly wound wire coil for compression resistance. Such a composite design provides tensile and compression resistance while maintaining flexibility. The outer proximal shaft  144   p  may further be designed to enable contrast injection through an introducer sheath while the delivery system is in place, for example, to allow for anatomical landmarking. The catheter  140  of  FIG. 9A  also shows an inner member  142  that includes a braid reinforced tube  142   b , tightly wound wire coil  142   c , a tapered distal tip  142   t  and a scaffold lock  142   s . The braid reinforced tube  142   b  and tightly wound coil  142   c  provide compression resistance and tensile strength while maintaining flexibility. An axial wire (not shown) may be incorporated into the wall of the inner member  142  to further increase tensile strength. The distal tip  142   t  has an atraumatic nosecone as a tapered distal tip  142   t  to facilitate tracking over a guidewire through tight anatomy and to prevent vessel trauma. The scaffold lock  142   s  is attached to the inner member  142  near the distal end. 
         [0051]    Additional detail of the scaffold lock  142   s  is provided in  FIG. 9B . The tines  142   st  of the scaffold lock  142   s  may fit, for example, into diamonds of a braided scaffold (or a cell of another scaffold design) and secure the scaffold during capture and deployment. Multiple scaffold locks may be used. Alternatively or in addition, another scaffold securement feature such as a polymeric pad may be used for scaffold securement. 
         [0052]    The pin lift  130  shown in  FIGS. 1A and 1B  includes a plurality of tapered distal projections  130   t . A funnel assembly  115  comprising a body portion  150 , clamp (not shown), pin lift  130  and tapered funnel structure  110 , along with a catheter (outer proximal shaft  144   p , inner member  142  and tapered distal tip  142   t  shown), is shown in perspective view of  FIG. 7 . As further seen from  FIG. 7 , the pin lift includes a collar  130   c  from which four pairs of tapered projections  130   t  extend distally, each pair of tapered projections of  130   t  forming a slot  130   s . Also shown in  FIG. 7  are the slots  110   s  (four total) of the tapered funnel structure  110 . The pin lift  130  and tapered funnel structure  110  are supported by the body portion  150 . 
         [0053]    A further view provided in  FIG. 8A  shows a delivery system  100  comprising a catheter (outer proximal shaft  144   p , outer distal capsule  144   d , inner member  142  and tapered distal tip  142   t  numbered), a funnel assembly  115  (including a body portion  150  with roller clamp  152  for holding the catheter in place, a pin lift  130 , and a tapered funnel structure  110 ), and loading aid assembly  120  (including outer housing  122   h , inner collar  122   c , loading pin assemblies  124   a  and scaffold) (scaffold not shown). 
         [0054]    Further detail of one half of the pin lift  130  (tapered projections  130   t  and slot  130   s  also numbered) is provided in the perspective view in  FIG. 8B . Further detail of one quarter of the tapered funnel structure  110  (distal end  110   d  and tapered region  110   t  also numbered) is provided in the perspective view in  FIG. 8C . 
         [0055]    Turning back to  FIGS. 1A and 1B , the loading aid assembly  120  is configured to be placed over the tapered funnel structure  110  of the funnel assembly  115  such that the scaffold  200  is guided into the distal end  110   ld  of the loading lumen  110   l . During this process, the loading aid assembly  120  receives the distal end  110   d  of the tapered funnel structure  110  within the receptacle lumen  1221  via the lumen opening at the proximal receptacle end  122   p , such that longitudinal movement of the loading aid assembly  120  in a proximal direction relative to the funnel assembly results in proximal longitudinal movement of the loading pin shafts  124   p  into the slots  110   s  of the tapered funnel structure  110  and in proximal longitudinal movement of the proximal end  200   p  of the scaffold  200  into the loading lumen  110   l.    
         [0056]    Turning now to  FIGS. 2A and 2B , further longitudinal movement of the loading aid assembly  120  in a proximal direction relative to the funnel assembly  115  results in further proximal longitudinal movement of the loading pin shafts  124   p  into the slots  110   s  of the tapered funnel structure  110  and further proximal longitudinal movement of the scaffold  200  into the loading lumen  110   l  up to a point where the loading pin shafts  124   p  engage stops  110   p  associated with the slots  110   s  of the tapered funnel structure  110 , thereby stopping the proximal progress of the loading aid assembly  120  relative to the funnel assembly  115 . At this point, the proximal end  200   p  of the scaffold  200  has been crimped to a diameter almost equivalent to the inner diameter of the outer distal capsule  144   d.    
         [0057]    In a next step, and with reference to  FIGS. 3A and 3B , the pin lift  130  is pushed distally forward into a gap  122   g  between the inner collar  122   c  and outer housing  122   h  of the loading aid assembly  120 . As the pin lift  130  is pushed distally forward, the tapered projections  130   t  advance on either side of the loading pin shafts  124   p , such that the loading pin shafts  124   p  are positioned in the slots  130   s  between each pair of projections  130   t . As seen in  FIGS. 3A and 3B , the enlarged loading pin heads  124   e  are beveled, allowing the tapered projections  130   t  to wedge under the enlarged loading pin heads  124   e , overcoming the radially inward forces exerted by the pin springs  124   s  and moving the loading pin shafts  124   p  radially outward from the center axis  100   a  of the assembly. Radially outward movement of the loading pin shafts  124   p  leads to disengagement of the loading pin shafts  124   p  from the scaffold  200  and removal of the loading pin shafts  124   p  from the longitudinal slots  110   s  of the tapered funnel structure  110 . A snap feature may be used to lock the collar  130   c  of the pin lift  130  to the loading aid assembly  120  once the pin lift  130  is distally advanced to a distal-most position relative to the loading aid assembly  120 . 
         [0058]    With reference to  FIGS. 4A and 4B , once the loading pin shafts  124   p  have been removed from the longitudinal slots  110   s  of the tapered funnel structure  110  by the pin lift  130 , the loading aid assembly  120  may undergo further longitudinal movement in a proximal direction relative to the funnel assembly  115 . Because the inner luminal surface of the inner collar  122   c  of the loading aid assembly  120  is provided with a taper in the particular embodiment shown, such further longitudinal movement acts to close the pin slots  110   s  and reduces the inner diameter of the tapered funnel structure  110 , including the inner diameter of the tapered region  110   t  of the loading lumen  110   l  therein, which further reduces the inner diameter of at least the proximal end  200   p  of the scaffold  200 . A perspective view of the system at this point is provided in  FIG. 10 . 
         [0059]    The inner member  142  may then be retracted relative to the outer sheath  144 . During retraction, the scaffold lock  142   s  engages the proximal end of the scaffold  200   p  and draws the remainder of the scaffold  200  through the tapered region  110   t  of the loading lumen  110   l  and into the outer distal capsule  144   d  of the delivery catheter. 
         [0060]    With reference now to  FIG. 11 , a delivery catheter handle  300  such as the Versatility™ universal handle available by Vention Medical Inc., South Plainfield, N.J., USA, may be used to translate the two coaxial shafts  142 , 144  of the catheter. The handle shown has two thumbwheels  302 , 304 , which are attached to each of the shafts  142 , 144 . A ball screw translates rotational motion to linear motion to move each of the shafts  142 , 144 . Also shown is a flush port  312  for flushing the outer sheath  144  and a second flush port  314  for flushing the inner guidewire lumen of the inner member  142 . 
         [0061]    Once loaded, the outer sheath  144  constrains the scaffold (in the outer distal capsule  144   d ) for delivery and expansion into the vessel. The inner member  142  may provide a lumen by which the delivery catheter  140  tracks over a guidewire (not shown). The outer sheath  144  facilitates a fixed distance from the operator to the delivery site and the system allows for controlled movement of the inner  142  and outer  144  components to accurately deploy the scaffold  200 . Once the delivery catheter  140  is tracked over a guidewire to the intended implant location, deployment may be achieved by rotating the proximal thumbwheel  302  which retracts the outer sheath  144 , allowing the scaffold to expand into the intended body lumen. The scaffold lock feature  142   s  secures the scaffold&#39;s  200  proximal end  200   p  within the delivery catheter, such that recapture or repositioning is possible up to a certain point in deployment if the operator is not satisfied with the initial deployment location. 
         [0062]    Although various embodiments are specifically illustrated and described herein, it will be appreciated that modifications and variations of the present disclosure are covered by the above teachings and are within the purview of the appended claims without departing from the spirit and intended scope of the disclosure.