Abstract:
Devices for loading a collapsible implant onto a delivery catheter. In one aspect, a loading device comprises an outer tubular structure and an inner tubular structure. The outer tubular structure comprises a narrowing passage configured to receive a catheter at one end and a collapsible implant at another end. The inner tubular structure is configured to move slidably and co-axially within the outer tubular structure. The inner tubular structure comprises a carrier pin configured to move within the narrowing passage as the inner tubular structure slides into the outer tubular structure. The sliding of the inner tubular structure into the outer tubular structure causes an implant mounted on the carrier pin to collapse as the implant moves through the narrowing passage and into the distal end of a catheter. In an optional aspect, the outer tubular structure further comprises a grasper to stabilize the catheter for receipt of the collapsible implant, and the internal diameter of the inner tubular structure varies to cause the grasper to first contract and stabilize the catheter, and then expand and release the catheter, as the grasper moves into the inner tubular structure.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/893,940 (Attorney Docket No. 017534-004500US), filed on Mar. 9, 2007, the full disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates generally to implants, and specifically to devices for loading a collapsible implant onto a delivery catheter, and more particularly for loading a collapsible pulmonary implant onto a delivery catheter. 
         [0004]    2. Description of the Background Art 
         [0005]    Collapsible self-expanding implants are well known in the medical device field. Historical medical uses for such implants include maintaining openings in vascular, urinary, biliary, esophageal, and renal tracts, and vena cava filters. Recently, modified pulmonary implants are being contemplated for the treatment of pulmonary disorders. Some such pulmonary devices differ from conventional occlusive devices in that they are designed to constrict, block, or significantly restrict fluid flow in a pulmonary passageway, rather than maintain an opening in it. 
         [0006]    Self-expanding pulmonary implants must be compressed to enable delivery through relatively small and curved body pathways. A delivery device, such as a delivery catheter, retains the pulmonary implant in its radially compressed state as it transports the implant to a treatment site through relevant bodily passageways. There, the implant is released and expands to its non-compressed shape. 
         [0007]    One of the challenges for the delivery of such pulmonary implants is accurately loading the implant onto the delivery catheter without dropping or damaging the device. The physician or nurse attempting to load the implant onto the catheter often finds it difficult to perform the task. Therefore, devices for loading implants onto delivery catheters are desirable. 
         [0008]    Also, implants that are already pre-loaded onto a catheter might lose some of their functionality as they remain on the shelf for extended periods of time before they are used in a patient. Ideally, the device would be maintained in its native state until it is ready to be used in a patient. When ready to be used, the physician should be able to load the implant onto the delivery catheter using a simple maneuver. Furthermore, the implant should be well protected during shipping and transfer until it is ready to be used. A simple system that would meet all the above needs would be highly desirable. 
         [0009]    U.S. Pat. No. 6,096,027 discloses an apparatus for loading a stent onto a catheter using a flexible sleeve to encase the stent as it is pulled through a tapered passageway. Commonly assigned published U.S. patent application No. 20060162731 A1 discloses a loading mandrel positioned within a loading body, wherein the loading mandrel is manipulated to load an occlusal stent into a wide-mouthed end of the loading body and move the occlusal stent to a narrow-mouthed end within the loading body. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    Devices for loading a collapsible implant onto a delivery catheter are disclosed. A loading device accepts a flexible and self-expanding implant, as well as the distal end of a delivery catheter. The loading device guides the implant through a narrowing passage that feeds into the distal end of the catheter. As the implant passes through the narrowing passage, it is compressed to a diameter that allows the implant to be inserted into the catheter. 
         [0011]    In one aspect, a loading device comprises an outer tubular structure and an inner tubular structure. The outer tubular structure comprises a narrowing passage configured to receive a catheter at one end and a collapsible implant at another end. The inner tubular structure is configured to move slidably and co-axially within the outer tubular structure. The inner tubular structure comprises a carrier pin configured to move within the narrowing passage as the inner tubular structure slides into the outer tubular structure. The sliding of the inner tubular structure into the outer tubular structure causes an implant mounted on the carrier pin to collapse as the implant moves through the narrowing passage and into the distal end of a catheter. Optionally, the outer tubular structure further comprises a grasper to stabilize the catheter for receipt of the collapsible implant, and the internal diameter of the inner tubular structure varies to cause the grasper to first contract and stabilize the catheter, and then expand and release the catheter, as the grasper moves into the inner tubular structure. 
         [0012]    In another aspect, the loading device comprises an outer shaft comprising a narrowing passage leading to an opening for receiving the distal end of a catheter, an opening for accepting a collapsible implant, and two compression members. The first compression member is configured to move slidably within the outer shaft and guides the implant through the narrowing passage, thereby collapsing it. The second compression member then inserts the implant into the catheter. 
         [0013]    In another aspect, the loading device comprises two tubular structures with opposing narrowing inner diameters, with one tubular structure configured to move slidably over the other. Placement of an implant between the structures, followed by sliding one tubular structure over the other, causes the implant to radially compress within the two opposing narrowing cavities. 
         [0014]    In another aspect, a catheter with a slotted rod is configured to hold and pull a collapsible implant through a narrowing passage and into the distal opening of the catheter. In another aspect, the slotted rod comprises a spring loaded ball configured to increase the grip on the implant. In another aspect, the rod comprises a grasping or latching mechanism configured to latch onto the implant as the implant is pulled through the narrowing passage and into the catheter. In another aspect, the rod comprises a loop wire configured to secure the implant as the implant is pulled through the narrowing passage and into the catheter. The loop wire may comprise shape-memory material such as Nitinol to allow it to release the implant by increasing the slack in the loop wire. 
         [0015]    The present invention further provides sterile kits for distributing and storing the system components. The kits will include packaging for holding the components, usually including a primary package which may be a box, pouch, cylinder, or other protective package. The individual system components are usually held within separate sterile containers within the primary package, usually being in pouches, cylinders, or the like. As a particular advantage of the present invention, self-expanding implants may be preloaded within the loading device and held in their uncollapsed configuration, thus reducing the risk of damaging the elastic implant materials prior to loading and implantation. Optionally, the kits may comprise instructions for use setting forth any of the loading methods described herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which: 
           [0017]      FIGS. 1   a - 1   g  show a loading device, in accordance with a first embodiment of the present invention. 
           [0018]      FIG. 2  shows an alternative embodiment of the loading tool according to the present invention. 
           [0019]      FIGS. 3   a - 3   e  show a loading tool according to yet another embodiment of the present invention. 
           [0020]      FIGS. 4   a - 4   e  illustrate a catheter with a slotted rod configured to hold and pull on the proximal end of a compressible implant. 
           [0021]      FIG. 5  illustrates a catheter with a rod comprising a spring loaded ball to increase the grip on a compressible implant. 
           [0022]      FIG. 6  illustrates a catheter with a rod comprising a latch mechanism to secure and pull a compressible implant. 
           [0023]      FIG. 7  illustrates a catheter with a rod comprising a loop wire to secure and pull an implant. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Although the detailed description contains many specifics, these should not be construed as limiting the scope of the invention but merely as illustrating different examples and aspects of the invention. It should be appreciated that the scope of the invention includes other embodiments not discussed in detail above. Various other modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the method and apparatus of the present invention disclosed herein without departing from the spirit and scope of the invention as described here. 
         [0025]    Various embodiments of a loading device are disclosed for loading a collapsible pulmonary implant onto a delivery system, in preparation for delivering the implant into the pulmonary airways of a patient. The delivery system may comprise a catheter. Collapsible pulmonary implants are made of memory-shape materials, such as Nitinol, and are compressed to enable delivery through relatively small and curved bodily pathways to the treatment site. Delivery devices, such as catheters, retain the collapsed pulmonary implants in a radially compressed state for delivery to the treatment site, where the implant is released into the airway and regains its non-compressed shape. The present invention discloses various embodiments of a loading device that collapses such implants and optionally inserts them onto a delivery catheter. The present invention further discloses various embodiments of catheters comprising rods for securing and pulling a collapsible pulmonary implant through a narrowing passage and into the catheter, collapsing the implant before it enters the catheter. As should be obvious to one of ordinary skill in the art, the present embodiments can be used with any implants that are delivered bronchoscopically for inducing atelectasis. Such implants may be restrictive or occlusive in nature, or valve-based. 
         [0026]      FIGS. 1   a - 1   g  illustrate a loading device  100  according to a preferred embodiment of the present invention. 
         [0027]      FIG. 1   a  shows the assembled loading device  100 . An inner tubular structure  102  is configured to move slidably into and out of an outer tubular structure  101 . The inner tubular structure  102  is hereinafter also referred to as a plunger  102 , and the outer tubular structure  101  is hereinafter also referred to as a barrel  101 . 
         [0028]    The plunger  102  comprises an optional cap  107 . A carrier pin  104  may be attached to the plunger  102  itself, or alternatively attached to the cap  107  as is shown in the Figures. A collapsible pulmonary implant  103  is mounted on the carrier pin  104 , positioned for compression through a narrowing passage and insertion into a catheter. One end of the barrel  101  is configured to receive the implant  103  mounted on the carrier pin  104 , and the other end is configured to receive a catheter (as is shown in the additional figures below). As the plunger  102  slides into the barrel  101 , the carrier pin  104  guides the implant  103  through the narrowing passage  106 , compressing the implant  103  and inserting it into the opening at the distal end of the catheter. 
         [0029]    The barrel  101  comprises optional finger rests  110 . Finger rests  110  and cap  107  allow a user to place two fingers in the finger rests  110  and hold the loading device  100  while using the thumb or the palm of the hand to slide the plunger  102  into the barrel  101 , similar to using a syringe or a pump, as shown in  FIG. 1   e.    
         [0030]      FIG. 1   b  shows an exploded view of the components of the loading device  100 , showing the barrel  101  with optional finger rests  110 , the plunger  102 , a cap  107 , a carrier pin  104 , a narrowing passage  106 , a catheter passage  109 , an optional grasper  108 , and a collapsible implant  103 . 
         [0031]      FIGS. 1   c  and  1   d  show interior and cross-sectional views of the loading device  100 , with a catheter  105  inserted into the loading device  100 . As shown, the loading device  100  comprises a narrowing passage  106 . Movement of the implant  103  into the narrowing passage  106  compresses the implant  103 , thereby reducing its diameter until the diameter is small enough to fit into the catheter  105 . A continuation of the same plunging motion that compresses the implant  103  also inserts it into the catheter  105 . As shown in  FIG. 1   d , the catheter  105  comes to rest as it comes in contact with indentations  112 . A user compresses the loading device, as shown in  FIG. 1   e , thereby causing tubular structure  102  to move into tubular structure  101 . 
         [0032]    Still referring to  FIGS. 1   c  and  1   d , the loading device  100  optionally comprises a grasper  108 . The grasper  108  is configured to grasp down on an inserted catheter  105  upon application of a force, which is provided by the tapered cavity of the plunger  102 . This cavity comprises a first section with a reduced internal diameter  111   a  and a second section with a larger internal diameter  111   b , as depicted in  FIG. 1   d.    
         [0033]    Prior to the plunger  102  sliding into the barrel  101 , the grasper  108  is in an open, released state. The sliding of the plunger  102  into the barrel  101  forces the grasper  108  through the reduced diameter section of the plunger  102  and causes the grasper  108  arms to close. As a result, the grasper  108  grasps and holds down the catheter  105 , thereby stabilizing the catheter  105  for the insertion of the compressed implant  103  during the movement of the loading device  100 . Upon moving through and exiting the reduced diameter section of the plunger  102  and entering the larger diameter section, the grasper  108  arms return to their open state, thereby releasing the loaded catheter  105  and allowing a user to remove the catheter  105  from the loading device  100 . 
         [0034]      FIG. 1   f  shows the loading device  100  in a partially compressed state. The plunger  102  has moved into the tubular structure  101 , and the carrier pin  104  has guided the implant  103  through the narrowing passage  106  and compressed it.  FIG. 1   g  shows the loading device  100  in a fully compressed state. When the loading device  100  is fully compressed, i.e., the plunger  102  has completed its travel from the proximal end of the barrel  101  to the distal end of the barrel  101 , the implant  103  has been inserted into the catheter  105 , and the grasper  108  has released the catheter  105  after passing through the reduced diameter section of the plunger  102 . In other words, the loading device  100  has, in one continuous motion, grasped (stabilized) the delivery catheter  105 , loaded the implant  103  onto the catheter  105 , and released the catheter  105  when the implant  103  has been loaded. This enables the user to conveniently load an implant  103  with the least amount of effort and ensure that it is loaded properly. 
         [0035]    Optionally, the loading device  100  is configured to allow a user to visually verify that the implant  103  is loaded onto the catheter  105 . For example, in one embodiment the plunger  102  and/or barrel  101  may comprise at least partially transparent material, such as glass or plastic. In another embodiment, the device  100  may comprise a cut-away portion serving as a viewing port. 
         [0036]    It is an advantageous aspect of the loading device  100  that it allows for loading the implant  103  at an accurate and predictable location within the catheter  105 . It is another advantageous aspect of the loading device  100  that it facilitates simple, straightforward, repeatable operation, providing ease of use. It is yet another advantageous aspect of the loading device  100  that it prevents damage to the implant  103  during shipping, storage, and loading operation. It is yet another advantageous aspect of the loading device  100  that it prevents the implant  103  from resting on its side over an extended period of time, thereby preventing damage to, or functional degradation of, the implant  103 . One of the most important advantages offered b the loading device  100  is that it prevents insertion of the implant  103  onto the catheter  105  in an incorrect (i.e., reversed) distal-proximal orientation. It is yet another advantageous aspect of the loading device  100  that it can be sterilized together with the implant  103  and separately from the catheter  105 . It is yet another advantageous aspect of the loading device  100  that it prevents damage to the catheter  105  during loading. The loading device  100  may be made of light-weight materials, as well as an intuitive form factor, and thus making it easy it to handle. 
         [0037]      FIG. 2  shows a loading device  200  according to a second alternative embodiment of the present invention. Loading device  200  comprises an elongate outer shaft  208  comprising a narrowing passage  206  leading to an opening  205  for receiving the distal end of a catheter (not shown). The loading device  200  comprises a first stage compression member  207  configured to move slidably within the outer shaft  208 , and a second stage compression member  204  configured to move slidably within the first stage compression member  207 . 
         [0038]    The first stage compression member  207  comprises a handle  201  protruding through an opening  210  on the side of the outer shaft  208 . The second stage compression member  204  comprises a handle  202  protruding through an opening  211  of the outer shaft  208 . The two compression members  207  and  204  are connected to each other via a tether  212 . 
         [0039]    To load a implant  103  onto a catheter  105  using the loading device  200 , the implant  103  is inserted into through an opening  209  into the loading device  200 , and the distal tip of a catheter  105  is inserted into the opening  205 . The catheter&#39;s tip is secured to the loading device  200  prior to insertion of the implant  103 . 
         [0040]    Once the catheter tip is inserted into and secured to the loading device, a user uses handle  201  to slide the first stage compression member  207  towards the narrowing passage  206 . The first stage compression member  207  guides the implant  103  through the narrowing passage  206 , thereby compressing the implant  103 . When the first stage compression member  207  completes its range of motion, the implant  103  is sufficiently compressed to allow the second stage compression member  204  to insert the implant  103  into the catheter  105 . Since the two compression members are tethered together, the second stage compression member  204  follows as the first stage compression member  207  completes its range of motion. At that point, the user uses the handle  202  to slide the second stage compression member  204  forward, guiding the now compressed implant  103  through the remainder of the narrowing passage  206  and into the opening at the distal end of the catheter  105 . 
         [0041]      FIGS. 3   a - 3   e  show a loading device  300  according to a third alternative embodiment of the present invention. Referring to  FIG. 3   a , the loading device  300  comprises two tubular structures  301  and  302 , with tubular structure  302  configured to move slidably over tubular structure  301 . The tubular structures  301  and  302  each have a narrowing inner cavity, with opposing directions of narrowing, as can be seen in  FIG. 3   b . Tubular structure  301  has an opening for insertion of a catheter  105 . Placement of the implant  103  between tubular structures  301  and  302 , followed by the sliding of tubular structure  302  over tubular structure  301 , causes the implant  103  to radially compress within the two opposing narrowing cavities and slide into the catheter  105 . 
         [0042]      FIG. 3   c  shows a cross-sectional view of the separated tubular structures  301  and  302 . Once the tubular structures  301  and  302  are separated, the user positions a implant  103  between them and slides tubular structure  302  over tubular structure  301  to compress the implant  103  and insert it into the catheter  105 , as seen in  FIGS. 3   d  and  3   e.    
         [0043]      FIGS. 4   a - 4   e ,  5 ,  6  and  7  show catheter  105  comprising members for loading an uncompressed implant  103  onto the catheter  105 , in accordance with embodiments of the present invention. In these embodiments, the catheter  105  comprises a lumen or sheath, and a member within the lumen or sheath that extends distally out of the catheter  105  and attaches itself to an uncompressed implant  103 , pulls the implant  103  through a narrowing passage to compress the implant  103 , and then continues to pull the now compressed implant  103  into the catheter  105 . We now turn to describing the various embodiments. 
         [0044]      FIGS. 4   a - 4   e  illustrate a catheter  105  with a slotted rod  601  configured to hold the proximal end (such as a bushing) of a compressible implant  103 , in accordance with an embodiment of the present invention. The catheter is inserted through a narrowing passage  602 . In the embodiments described herein, the rod may be a hypotube, a coil, a solid wire, or any other such element that can be rigid. 
         [0045]    Referring to  FIG. 4   a , the slotted rod  601  is extended distally out of its encasing catheter  105 . Referring to  FIG. 4   b , the uncompressed implant  103  is placed within the slot. The slotted rod  601  then pulls the implant  103  through the narrowing passage  602  and compresses it (not shown) to a diameter that is small enough to be inserted into the internal lumen of the catheter  105 . Finally, the collapsed implant  103  is pulled into the catheter  105 , as shown in  FIG. 4   c.    
         [0046]    Once compressed and stored within the catheter  105 , the implant  103  can be released from the catheter  105  by extending the rod  601  distally out of the catheter  105 , or alternatively by pulling the catheter lumen or sheath back to expose the rod  601 . Referring to  FIGS. 4   d  and  4   e , once the implant  103  has been deployed into the bronchial passageway of a patient, the user can twist or turn the rod  601  and disengage the implant  103 . 
         [0047]    In an optional embodiment, the rod may comprise a mechanism for more tightly gripping the implant  103 . Referring to  FIG. 5 , a rod  603  is shown comprising a spring  603   a  and a spring loaded ball  603   b  to increase the grip on the implant  103 . Referring to  FIG. 5 , the slotted rod  603  is pushed out of its catheter (not shown). To load the implant  103 , the bushing of the implant  103  is placed within the slot and the spring loaded ball  603   b  exerts a gripping pressure against the implant  103 , holding it tightly in place. The implant  103  is then pulled into the narrowing passage  602  and compressed to a diameter smaller than that of the internal lumen of the catheter (not shown) and further pulled into the catheter. Once compressed, the implant  103  can be released again from the catheter by pushing the rod  603  out of the catheter, or alternatively by pulling the catheter lumen or sheath back to expose the rod  603 . As described above, once the implant  103  has been deployed into the bronchial passageway of a patient, the user can twist and turn the rod  603  to disengage the implant  103 . 
         [0048]    In an alternative embodiment, the rod may comprise an attachment mechanism such as a latch mechanism to latch onto the implant  103 . 
         [0049]    Referring to  FIG. 6 , the rod  604  comprises a latch  604   a  and is extended distally out of its encasing catheter  105 . To load the implant  103 , the bushing of the implant  103  is placed within the latch  604   a  and locked into place. As above, the implant  103  is then pulled through the narrowing passage  602  and compressed to a diameter smaller than that of the internal lumen of the catheter  105 . Once compressed, the implant  103  can be released again from the catheter  105  by pushing the rod  604  out of the catheter  105  (or alternatively by pulling the catheter lumen or sheath back to expose the rod  604 ) and releasing the latch  604   a . Once the implant  103  has been deployed into the bronchial passageway of a patient, releasing the latch  604   a  causes the rod  604  to disengage from and release the implant  103 . 
         [0050]    In an alternative embodiment, the rod may comprise a loop wire as an attachment mechanism to secure the implant  103  to the rod. This is illustrated in the embodiment shown in  FIG. 7 . The rod  605  comprises a loop wire  605   a  that protrudes out of its encasing catheter  105  and loops around the bushing of the implant  103 , pulling the implant  103  into the narrowing passage  602  and compressing it to a diameter smaller than that of the internal lumen of the catheter  105 . The loop wire  605   a  may comprise shape memory material such as Nitinol to allow it to release the implant  103  by increasing the slack in the loop wire  605   a.    
         [0051]    While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims.