Abstract:
Funnel-trap type devices or systems made of braid are described for capture and retrieval or, instead, capture and subsequent release of Inferior Vena Cava (IVC) filters or other medical devices. Delivery and/or retrieval devices, kits in which they are included, methods of use and methods of manufacture are all contemplated.

Description:
FIELD 
       [0001]    The embodiments described herein relate to endovascular temporary Inferior Vena Cava (IVC) filter or other implant retrieval devices or system and methods. 
       BACKGROUND 
       [0002]    Temporary IVC filters are placed much like permanent filters, but are designed so that they may be retrieved in a separate endovascular procedure, generally from a femoral vein or an internal jugular vein approach. Most of the currently available temporary filters include a hook-like feature with which they can be captured and received within a catheter or sheath for removal by employing a gooseneck snare or a multi-loop snare. 
         [0003]    While retrieval is a simple procedure in principle, difficulty is often encountered capturing a filter&#39;s hook with the snare loop(s). Such difficulty is compounded when the filter is tilted or off-kilter in placement. Several filters are designed to avoid such orientation. However, the problem remains common because the device is not anchored into the IVC in a stable fashion. Constant blood flow in addition to blood clots can disorient the filter within the IVC making recapture difficult. Accordingly, there remains a need for filter improved retrieval systems. 
       SUMMARY 
       [0004]    The example embodiments described herein meet this and/or other needs, particularly with respect to addressing any complications experience during filter retrieval. Specifically, the subject devices or systems include feature(s) that allow for capture or retrieval and subsequent release of Inferior Vena Cava (IVC) filters or other medical devices if desired. In other words, the subject devices allow for reversal of IVC filter capture once it is achieved in case so-called “bail-out” is desired in order to avoid other complications. 
         [0005]    The ability to release a captured or hooked IVC filter may be desirable in cases where the amount of tissue ingrowth with the filter is greater than expected. Other reasons for wanting to (in a sense) reverse course during a filter retrieval procedure may by expressed by physicians with skill in the art. 
         [0006]    In the subject systems, the reversal option is both figurative and literal with respect to the operation of the design. Namely, features are provided for reconfiguring and reversing the orientation of a flap incorporated in the retrieval device that is otherwise intended to capture the IVC filter. In an inverted state, the flap in the retrieval device is configured to retain the filter. When the flap is everted (i.e., turned outward or inside out) it either releases or allows release of the filter. 
         [0007]    In one embodiment, a pusher wire is incorporated in the design to facilitate everting an otherwise inverted flap configuration. This wire may comprise a pair of filaments in side-by-side configuration, a pair (or more) of filaments twisted and set to form a wire cable, part of a catheter construction, or be otherwise configured. 
         [0008]    In another embodiment, a separate plunger or pusher element may be deployed through a lumen (optionally a central lumen) of the retrieval device and then be expanded and advanced further to effect flap eversion. In this example, the plunger device may be provided separately and tracked through a lumen in the retrieval device when desired for use. Alternatively, the plunger may be incorporated or housed in the retrieval device as in a kit or combination. 
         [0009]    However configured, the subject retrieval devices or systems, kits in which they are included (with and without assembly), methods of use and manufacture (including assembly of the constituent components in vivo or ex vivo) are all included within the scope of the present disclosure. Some aspects of the same are described above, more detailed discussion is presented in connection with the figures below. 
         [0010]    Other systems, devices, methods, features and advantages of the subject matter described herein will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, devices, methods, features and advantages be included within this description, be within the scope of the subject matter described herein, and be protected by the accompanying claims. In no way should the features of the example embodiments be construed as limiting the appended claims, absent express recitation of those features in the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The details of the subject matter set forth herein, both as to its structure and operation, may be apparent by study of the accompanying figures, in which like reference numerals refer to like parts. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the subject matter. Moreover, all illustrations are intended to convey concepts, where relative sizes, shapes and other detailed attributes may be illustrated schematically rather than literally or precisely. 
           [0012]      FIGS. 1A and 1B  are photographs of example embodiments of IVC filter variations as may be used in the present system. 
           [0013]      FIGS. 2A-2C  are side-sectional views depicting an example embodiment of a first retrieval system including reversible filter capture features. 
           [0014]      FIGS. 3A and 3B  are side-sectional views depicting another example embodiment of a retrieval system including a plunger for filter capture feature reversal. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Before the present subject matter is described in detail, it is to be understood that this disclosure is not limited to the particular example embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be limited only by the appended claims. 
         [0016]    All features, elements, components, functions, and steps described with respect to any embodiment provided herein are intended to be freely combinable and substitutable with those from any other embodiment. If a certain feature, element, component, function, or step is described with respect to only one embodiment, then it should be understood that that feature, element, component, function, or step can be used with every other embodiment described herein unless explicitly stated otherwise. This paragraph therefore serves as antecedent basis and written support for the introduction of claims, at any time, that combine features, elements, components, functions, and steps from different embodiments, or that substitute features, elements, components, functions, and steps from one embodiment with those of another, even if the following description does not explicitly state, in a particular instance, that such combinations or substitutions are possible. Express recitation of every possible combination and substitution is overly burdensome, especially given that the permissibility of each and every such combination and substitution will be readily recognized by those of ordinary skill in the art upon reading this description. 
         [0017]      FIG. 1A  shows a GÜNTHER TULIP (Cook Medical, Inc.) temporary IVC filter  10  with a hook  12  end interface for retrieval. As shown in  FIG. 1B  for an IVC filter  20 , the hook may be modified or substituted for a nubbin-type interface  22 . The nubbin  24  may comprise a laser-formed or solder-formed protuberance or bump on an extension  26  from a hub  28 . Alternatively, a/the filter retrieval interface  22  may comprise a band (e.g., a Pt marker band) mounted (e.g., by swaging, welding, gluing, etc.) on a/the extension  26 . However the enlargement is created, its interaction with the rest of the system for capture and/or release will be apparent in the following figures. 
         [0018]      FIG. 2A  provides a cross-sectional view of a distal end of a retrieval system  100  that is adapted to release or reversibly capture a medical device (such as filter  10  or  20 ). System  100  includes a shaft  30  with a distal extension  40  in the form of a funnel-trap structure made of braid material. In use with a patient&#39;s vasculature, the shaft is received within an elongate sleeve  60  (that may be a commercially available catheter or a custom part of the overall system  100 ). 
         [0019]    In the various system architectures, the catheter or pusher shaft and/or sleeve  30  (and that of the plunger detailed further below) may include a simple extrusion (e.g., PTFE, FEP, PEEK, PI, etc.) or may be constructed using conventional catheter construction techniques and include a liner, braid support and outer jacket, metal hypotube, etc. The frame of filter  10  or  20  may be constructed using conventional laser cutting and electropolishing techniques and/or be otherwise constructed. In embodiments intended for tracking through a guide/delivery catheter without an incorporated sheath, a loading sheath may be employed. Advantageously, any such loading sheath is splittable. Other typical percutaneous access instruments (such as wires, etc.), valves and other hardware may also be employed in connection with the embodiments. 
         [0020]    The funnel-trap structure  40  may be made as a subassembly and attached to the catheter/pusher shaft. International Patent Application No. PCT/US14/42343 and U.S. patent application Ser. No. 14/569,500, each of which are incorporated by reference herein in their entirety for all purposes, detail optional steps in the manufacture of a pre-form for constructing the funnel-trap portion of the final device. In general, the aforementioned forming methods are ones in which a heatset (possibly multiple-staged heatset) preform is provided that is substantially cylindrical in shape and includes an interior folded “flap” section. As such, the preform resembles the subject device in its fully compressed state for catheter tracking Then, the preform is expanded (e.g., in a conical shape) to a desired “working” diameter and heatset accordingly. It may be heatset into a conical shape and be ready for mounting, or it may be heatset in a conical shape and transformed to a conical shape by mounting to catheter body  30 . 
         [0021]    The braid from which the retrieval system extension  40  is optionally made may comprise Nitinol (preferably that is superelastic at body temperature), CoCr, Stainless Steel or another biocompatible material. The braid advantageously incorporates between 72 and 288 (more typically between 96 or 144 and 192) filament “ends” in a 1-over-1, a 2-over-2 or other maypole braided pattern. With (superelastic) Nitinol, the wire is advantageously between about 0.001 and about 0.003 inches in diameter. In which case, a supple and relatively “smooth” matrix surface is provided from which to construct the flexible funnel-trap architecture shown and described. The value of such a surface is in its atraumatic aspect and/or ability to help guide in IVC filter interface into position for capture even if it is oriented off-angle. To further assist with recapture, the funnel trap structure may be selectably directable. 
         [0022]    The braid may include so-called “axial” filaments as well. These may be used to improve column strength in a finally-formed device. The axial filaments may be incorporated in a/the maypole braided pattern when it is being formed or be added later manually. Alternatively, (and as shown in  FIG. 2A ) the funnel trap structure  40  may include interposed support member(s) # as further described in U.S. Provisional Patent Application Ser. No. 62/091,433, which is incorporated by reference herein in its entirety for all purposes. 
         [0023]    The so-called “funnel trap” structure or extension  40  may be generally frusto-conical in shape as shown or otherwise configured. With an outer conical shape (i.e., triangular shape in cross section) the structure is highly supportive for any necessary or desirable tissue discretion that might need to occur to free an emplaced filter. Still, the device may be bowed outward along its sides or otherwise configured. 
         [0024]      FIG. 2A , illustrates further constructional options and details. Here, inner and outer braid layers  42 / 42 ′ are heatset using conventional techniques (e.g., in a furnace, salt pot, etc.) in a funnel shape with distal bends  44  in the braid wire forming an outer rim  46  with a large(r) distal opening  48  and meeting at inner bends  50  forming an inner opening or rim  52  with a small(er) more proximal opening  54 . Stated otherwise, the braid used to construct the funnel-shape trap is folded back (e.g., in a flap  56 ) at the distal opening to provide a more proximal opening. 
         [0025]    Importantly, the distal rim opening  48  is larger than the more proximal rim opening  54  to operate in guiding filter engagement feature(s) or enlargement  12 / 24  into a pocket  58  proximal to and/or radially adjacent flap  56  where it is captured and subsequently locked upon advancing sleeve  60 . Initial capture of filter  10  in this manner is shown in  FIG. 2B . 
         [0026]    To help ensure capture, the sleeve  60  may be advanced fully over trap section  40  before withdrawal into a separate catheter. In other words, advancing sleeve  60  (be it a system or device-integral sleeve or in situ catheter) over funnel section  40  “closes the trap” and securely captures the implant to be retrieved. Otherwise, shaft  30  may be withdrawn until the implant is pulled into the access catheter originally used to introduce system  100 . Any or all such activity may be visualized fluoroscopically by a physician by way of marker features incorporated in system  100 . 
         [0027]    Notably, system  100  may be used identically when capturing a filter  20  with a more nub or nubbin  24  end interface. In which case, the capture reversal features detailed below may not need to be used to release the implant end. However, by so-including the features, a solution is provided to handle a wider array of filters and any need for release of capture, once achieved. 
         [0028]    Regarding the subject capture release or reversal features, in the embodiment shown in  FIGS. 2A-2C , these are provided in connection with inner shaft  62  and push “wire”  64 . In the configuration shown (and fully labeled with callouts in  FIG. 2B ), wire filaments are looped over or through a section of rim  52  forming a “U” shape  66  secured by a band  68  (such as a crimped PT marker band). Secured to the braid as such, when wire  64  is advances as shown in  FIG. 2C , the flap section  56  of extension  40  can be moved from an inverted configuration to an everted configuration. This frees hook  12  of the filter  10 . 
         [0029]    The action for expelling or releasing hook  12  is clearly apparent. It may be accompanied with withdrawing shaft  30  so that the hook can slip out of the reversed flap. Moreover, flap  56  may incorporate a coating  70  (e.g., TICOFLEX urethane coating) on its inner surface in order to secure the braid against entanglement or entrapment of the hook if pulled into the flap when the device is in the configuration shown in  FIG. 2B . 
         [0030]    The system  100 ′ in  FIGS. 3A and 3B  is similar to the above except that a more complex pusher  200  is substituted for pusher wire(s)  64 . This pusher  200  may be received within lumen  72  of catheter body  30  (as was wire  64 ). 
         [0031]    Pusher  200  may be regarded or referred to as a “plunger” given its function as seen the figures. Namely, pusher  200  is advanced within lumen  72  after its expansion within the funnel trap extension  30  of the system and used to push flap  56  outward to effect implant engagement feature release. The pusher may reside in lumen  72  during introduction of system  100 ′ during a medical procedure. Alternatively, it may be packages separately and inserted and tracked through lumen  72  “on-demand” if a physician decides that release of a captured implant  10  is somehow desirable. 
         [0032]    In any case, pusher  200  comprises a sleeve  202  and an expandable distal section  204 . The expandable distal section may comprise braid as shown. A pull wire  206  for braid actuation from pushed-out and compressed, to pulled-in an expanded may be included within the sleeve. Otherwise, the braid (or other material such as tube-cut Nitinol stent architecture) may be heatset in the enlarged configuration to self-expand once exiting lumen and connected to a distal end. 
         [0033]    In the variation shown in  FIGS. 3A and 3B  (i.e., with the braid-based section  204 ) the distal ends of the braid may be secured to wire  206  within a distal Pt marker band  208 . Another marker band  210  may be provided at a proximal end of the expandable section securing the proximal ends of the braid to braid ends to sleeve or shaft  202 . As such, when pull wire  206  is actuated, the expansion and/or contraction of section  204  can be detected (i.e., by viewing actuation of the markers) even if it the material of the expandable section is not itself fluoroscopically visible. 
       VARIATIONS 
       [0034]    The subject methods, including methods of use and/or manufacture, may be carried out in any order of the events which is logically possible, as well as any recited order of events. Medical methods may include any of a hospital staffs activities associated with device provision, implant positioning, re-positioning, retrieval and/or release. 
         [0035]    Furthermore, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in the stated range is encompassed within the disclosure. Also, it is contemplated that any optional feature of the embodiments described may be set forth and claimed independently, or in combination with any one or more of the features described herein. 
         [0036]    Reference to a singular item includes the possibility that there are a plurality of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said,” and “the” include plural referents unless specifically stated otherwise. In other words, use of the articles allow for “at least one” of the subject item in the description above as well as the claims below. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. 
         [0037]    While the embodiments are susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that these embodiments are not to be limited to the particular form disclosed, but to the contrary, these embodiments are to cover all modifications, equivalents, and alternatives falling within the spirit of the disclosure. Furthermore, any features, functions, steps, or elements of the embodiments may be recited in or added to the claims, as well as negative limitations that define the scope of the claims by features, functions, steps, or elements that are not within that scope.