Patent Publication Number: US-11648021-B2

Title: Retrieval apparatus and methods for use

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/350,057, filed Nov. 13, 2016, and published as U.S. Patent App. Pub. No. 2017/0056034 on Mar. 2, 2017, which is a continuation of U.S. patent application Ser. No. 12/746,920, filed Jun. 8, 2010, and published as U.S. Patent App. Pub. No. 2010/0268265 on Oct. 21, 2010, which is a National Stage Entry of International Patent App. No. PCT/US2008/086298, filed Dec. 10, 2008, and published as International Patent App. Pub. No. WO 2009/076482 on Jun. 18, 2009, which claims the benefit of both U.S. Provisional Patent App. Nos. 61/12,722, filed Dec. 10, 2007, and 61/046,395, filed Apr. 18, 2008, the entire disclosures of which are expressly incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to apparatus for retrieving material within a body lumen of a patient. More particularly, the present invention relates to expandable and/or contractible apparatus for retrieving thrombus, objects, or other material within a body lumen, such as a blood vessel, aorto-venous fistula, tubular graft, and/or other body lumen within a patient&#39;s body, and to methods for making and using such apparatus. 
     BACKGROUND 
     Flow within a blood vessel or other body lumen within a patient&#39;s vasculature may be constricted or ultimately interrupted for a variety of reasons. For example, a vessel may gradually narrow due to inflammation and/or cell proliferation. In addition, thrombus may form due to such narrowing or other flow problems within a vessel. 
     For example, an aorto-venous graft may be implanted in an arm of a patient experiencing kidney failure, e.g., to facilitate dialysis treatment. Such grafts may be a fistula formed directly in the patient&#39;s body, e.g., through tissue between an adjacent artery and vein or other vessels, may be a xenograft implanted between two vessels, or may be a synthetic graft. Such grafts only have a limited life cycle due to inflammation, thrombus formation, and the like. Once such a graft becomes sufficiently occluded or otherwise deteriorates, a new graft must be implanted at a new location for subsequent treatment. 
     Accordingly, apparatus and methods for removing material from aorto-venous grafts, e.g., to extend the useful life of such grafts, and/or from other blood vessels or body lumens would be useful. 
     SUMMARY 
     The present invention is directed to apparatus for retrieving material within a body lumen of a patient, and, more particularly, to expandable and/or contractible apparatus for retrieving thrombus or other material within a body lumen, such as a blood vessel, aorto-venous fistula, and/or other body lumen within a patient&#39;s body, and to methods for making and using such apparatus. 
     In accordance with a first embodiment, an apparatus is provided for removing, retrieving, or otherwise capturing material within a body lumen that includes a shaft or other elongate member including a proximal end, a distal end sized for introduction into a body lumen, and terminating in a distal tip; and a basket device carried on the distal end. 
     The basket device generally includes a distal basket adjacent the distal tip and a proximal basket proximal to and spaced apart from the distal basket. Each of the baskets may include an open end communicating with an interior of the respective basket, the open ends oriented towards one another. At least one of the proximal and distal baskets may be movable towards the other for substantially enclosing and capturing material within the interiors of the baskets. Thus, the basket device may include an open region between the proximal and distal baskets that may be substantially enclosed when the proximal and distal baskets are directed towards one another. 
     For example, the elongate member may include a core wire carrying the distal basket, and an actuator member adjacent the core wire carrying the proximal basket. Thus, axial movement of the actuator member and core wire relative to one another may direct the proximal basket distally towards the distal basket and/or direct the distal basket proximally towards the proximal basket. In one embodiment, the actuator member may be a tubular body surrounding the core wire such that the core wire extends distally from a distal end of the tubular body. The core wire may be pulled proximally at least partially into the tubular body, or the tubular body may be advanced distally at least partially over the core wire to enclosed the basket device. 
     In one embodiment, the proximal and distal baskets are expandable from a contracted condition, e.g., sized for introduction into a body lumen, and an expanded condition sized, e.g., for contacting a wall of the body lumen and/or for capturing material within the open ends of the baskets. 
     In addition or alternatively, each of the proximal and distal baskets may include a circumferential wall and a closed end opposite the open end. The circumferential wall may include a plurality of openings therein, e.g., by forming the baskets from a mesh structure, such as a laser-cut tube or a wire mesh. 
     In one embodiment, the basket device includes a middle portion extending between the proximal and distal baskets. The middle portion, e.g., a mesh tubular structure that may partially engage material captured between the baskets, may have a cross-section that is smaller than the proximal and distal baskets in the expanded condition. The middle portion may be coupled to the proximal and distal baskets such that the middle portion may be directed laterally, e.g., to accommodate material being received between the baskets adjacent the middle portion. For example, the middle portion may be coupled to the baskets by a plurality of struts, e.g., extending between ends of the middle portion and the open ends of the proximal and distal baskets. The middle portion may be substantially flexible such that the middle portion is compressible axially when the proximal and distal baskets are moved towards one another for capturing material within the interiors of the baskets. For example, the struts may bend or otherwise deflect to accommodate the middle portion being received within the interiors of the baskets as the baskets are directed towards one another. 
     Optionally, the apparatus may include a sheath or other tubular member, e.g., for selectively covering and/or exposing the basket device. The tubular member may include a proximal end, a distal end sized for introduction into a body lumen, and a lumen extending between the tubular member proximal and distal ends. Before use, the basket device may be disposed within the lumen in the contracted condition, e.g., adjacent the distal end of the tubular member, such that the elongate member extends proximally within the lumen. The elongate member may be movable relative to the tubular member for deploying the basket device from the tubular member distal end. For example, the basket device may be directable to a contracted condition for placement within the tubular member lumen, and biased to resiliently expand to an expanded condition upon being deployed from the tubular member. 
     In addition or alternatively, the apparatus may include one or more actuators for selectively expanding and/or compressing the basket device between the contracted and expanded conditions. For example, the elongate member may include one or more balloons or other expandable members within the basket device that may be expanded to expand the basket device from the contracted to the expanded condition. 
     In accordance with another embodiment, an apparatus is provided for retrieving material within a body lumen that includes a core wire including a proximal end and a substantially atraumatic distal tip, and an actuator member adjacent the core wire and including a distal end disposed proximal to the distal tip. A distal basket is fixed axially relative to the core wire adjacent the distal tip and a proximal basket fixed axially relative to the distal end of the actuator member. The distal basket may include a proximal open end and a distal enclosed end defining an interior of the distal basket, and the proximal basket may include a distal open end and a proximal enclosed end defining an interior of the proximal basket. The basket device also includes a middle portion extending between the proximal and distal baskets. The middle portion may have a cross-section that is smaller than the proximal and distal baskets in the expanded condition. 
     The actuator member is movable distally relative to the core wire, e.g., to direct the proximal basket distally towards the distal basket, for substantially enclosing and capturing material within the interiors of the baskets. The middle portion may be compressible axially when the proximal basket is moved distally towards the distal basket, e.g., to accommodate receiving the middle portion within the interiors of the baskets along with material captured therein. 
     In accordance with yet another embodiment, an apparatus is provided for retrieving material within a body lumen that includes a core wire comprising a proximal end and a substantially atraumatic distal tip; and an actuator member adjacent the core wire and comprising a distal end disposed proximal to the distal tip, the actuator member movable distally relative to the core wire. A distal basket is fixed axially relative to the core wire adjacent the distal tip, the distal basket comprising a proximal open end and a distal enclosed end defining an interior of the distal basket; and a proximal basket fixed axially relative to the distal end of the actuator member, the proximal basket comprising a distal open end and a proximal enclosed end defining an interior of the proximal basket, the proximal basket movable distally towards the distal basket when the actuator member is moved distally relative to the core wire for substantially enclosing and capturing material within the interiors of the baskets. An actuator collar is slidable on the core wire within the interior of the distal basket, the collar coupled to the open end of the distal basket such that, when the actuator member is moved distally relative to the core wire, the collar applies an inward force to direct the open end of the distal basket radially inwardly. 
     In accordance with still another embodiment, a method is provided for removing, retrieving, or otherwise capturing material within a body lumen of a patient. A basket device may be introduced into the body lumen in a contracted condition, the basket device including a proximal basket and a distal basket spaced apart from one another. Each of the proximal and distal baskets may include an open end communicating with an interior of the respective basket, the open ends oriented towards one another. The distal basket may be deployed such that the distal basket expands within the body lumen and the open end is disposed distal to material to be removed, and the proximal basket may be deployed such that the proximal basket expands within the body lumen and the open end is disposed proximal to material to be removed. At least one of the proximal and distal baskets may be directed towards the other to capture the material through the open ends into interiors of the proximal and distal baskets. 
     In accordance with yet another embodiment, a method for retrieving, removing, or otherwise capturing material within a body lumen of a patient. A basket device is introduced into the body lumen, e.g., in a contracted condition. The basket device may include a proximal basket and a distal basket spaced apart from one another, each of the proximal and distal baskets including an open end communicating with an interior of the respective basket, the open ends oriented towards one another. The distal basket may be deployed such that the distal basket expands within the body lumen and the open end is disposed distal to material to be removed, and the proximal basket may be deployed such that the proximal basket expands within the body lumen and the open end is disposed proximal to material to be removed, e.g., after deploying the distal basket. At least one of the proximal and distal baskets may be directed towards the other to capture the material through the open ends into interiors of the proximal and distal baskets. 
     In one embodiment, the open end of the distal basket may be directed radially inwardly as the at least one of the proximal and distal baskets towards the other. For example, the at least one of the proximal and distal baskets may be directed towards the other until the open end of the distal basket is directed radially inwardly and received within the open end of the proximal basket. 
     Optionally, the proximal basket may be directed at least partially into a lumen of a tubular device, e.g., before withdrawing the tubular device from the body lumen. For example, the proximal basket may be directed entirely into the lumen of the tubular device, e.g., thereby compressing the proximal basket being radially inwardly as the proximal basket is directed into the lumen of the tubular device. In addition, the proximal basket may at least partially compress the distal basket radially inwardly when the proximal basket is directed into the lumen of the tubular device, e.g., allowing the distal basket to be directed into the lumen of the tubular device after the proximal basket is directed into the lumen of the tubular device. 
     Other aspects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It will be appreciated that the exemplary apparatus shown in the drawings are not necessarily drawn to scale, with emphasis instead being placed on illustrating the various aspects and features of the illustrated embodiments, in which: 
         FIG.  1    is a side view of a distal end of a first embodiment of an apparatus for capturing material from within a body lumen. 
         FIGS.  2 A- 2 E  are cross-sectional views of a body lumen showing a method for capturing material from the body lumen using the apparatus of  FIG.  1   . 
         FIG.  3    is a side view of a distal end of a second embodiment of an apparatus for capturing material from within a body lumen. 
         FIGS.  4 A- 4 D  are side views of the distal end of the apparatus of  FIG.  3   , showing actuation of the apparatus to collapse a distal basket of the apparatus and capture a portion of the distal basket within a proximal basket. 
         FIGS.  5 A- 5 F  are cross-sectional views of a body lumen showing a method for capturing material from the body lumen using the apparatus of  FIG.  3   . 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Turning to the drawings,  FIG.  1    shows an exemplary embodiment of an apparatus  10  for removing, retrieving, and/or otherwise capturing thrombus, objects, or other material from within a body lumen, such as a blood vessel, aorto-venous fistula, tubular graft, and the like (not shown). Generally, the apparatus  10  includes an expandable basket device  40  carried by a shaft or other elongate member  20 , and a sheath or other tubular member  30  for facilitating delivery and/or removal of the shaft  20  and basket device  40 . 
     In the embodiment shown, the shaft  20  includes a core wire  22  and an actuator member  24  disposed adjacent the core wire  22  that are movable axially relative to one another, the shaft  20  generally defining a central longitudinal axis  38  for the apparatus  10 . The core wire  22  may be a substantially flexible elongate member, e.g., a solid or hollow wire structure including a proximal end (not shown) and a distal end terminating in a distal tip  26 . As shown, the distal tip  26  may be substantially atraumatic, e.g., covered by a coiled wire and/or a polymeric covering, and/or may include a “J” or other rounded shape (not shown) to minimize risk of perforation or catching during advancement within a patient&#39;s body. 
     The actuator member  24  may be an elongate tubular body including a proximal end (not shown), a distal end  28  having a size for introduction into a body lumen, and a lumen  29  extending therebetween. The core wire  22  may be slidably received within the lumen  29  such that the core wire  22  extends from the lumen  29  beyond the distal end  28  and the distal tip  26  is spaced apart from the distal end  28  of the actuator member  24 . Alternatively, the actuator member  24  may be another elongate member, e.g., a wire or other rail (not shown) disposed adjacent to the core wire  22 , as long as the actuator member  24  and core wire  22  are movable axially relative to one another. 
     The core wire  22  and actuator member  24  may have sufficient length to extend from a target site within a patient&#39;s body to a location outside the patient&#39;s body. Alternatively, the core wire  22  and/or actuator member  24  may extend to and be coupled to other components of the apparatus  10  spaced apart from the basket device  40 . The core wire  22  and/or actuator member  24  may have sufficient column strength to allow advancement of the core wire  22  and/or actuator member  24  without substantial risk of buckling or kinking. For example, a distal region of the core wire  22  and actuator  24  may be relatively flexible and a proximal region may be substantially rigid or semi-rigid to facilitate advancement of the distal region from the proximal end of the apparatus  10 . The core wire  22  may be formed from a single wire strand, multiple strands, a coiled wire structure, and the like having a sufficiently small profile to be slidable received in the actuator member  24 . The actuator member  24  may be a formed from a hypotube, a multiple layer catheter structure, e.g., including a braid or other reinforcement and the like. 
     In an exemplary embodiment, the proximal ends of the core wire  22  and actuator member  24  may be received within and/or otherwise coupled to a handle (not shown). The handle may include an actuator, e.g., a slider control, button, and the like (not shown) for directing one of the core wire  22  and actuator member  24  axially relative to the other, as explained further below. In addition or alternatively, the handle may include one or more additional controls or actuator. For example, the handle may include an actuator for retracting the sheath  30  relative to the basket device  40  (or advancing the basket device  40  relative to the sheath  30 ), also as described further below. 
     The basket device  40  carried by the shaft  20  generally includes a distal basket  42   a  adjacent the distal tip  26 , and a proximal basket  42   b  proximal to and spaced apart from the distal basket  42   a . For example, the distal basket  42   a  may be attached to or otherwise fixed axially relative to the core wire  22 , e.g., adjacent the distal tip  26 , and the proximal basket  42   b  may be attached to or otherwise fixed axially relative to the actuator member  24 , e.g., to the distal end  28 . In addition, in the embodiment shown, the basket device  40  includes a middle portion  50  that extends between the distal and proximal baskets  42   a ,  42   b.    
     As shown in  FIG.  1   , each of the baskets  42  includes a circumferential wall  44  defining an open end  46  communicating with an interior of the basket  42  and a closed end  48  attached to the core wire  22  or actuator member  24 . The open ends  46  are oriented towards one another and initially spaced apart from one another, as shown in  FIG.  1   . Initially, the distance between the open ends  46  may be between about five and fifty millimeters (5-50 mm), e.g., to provide sufficient space between the baskets  42  to facilitate receiving material between the baskets  42  for retrieval. When the actuator member  24  and core wire  22  are moved axially relative to one another, the baskets  42  may be moved towards the other for substantially enclosing and capturing material within the interiors of the baskets  42 , e.g., as shown in  FIGS.  2 C- 2 E  and described further below. In addition or alternatively, the space between the baskets  42  may be adjusted by the user, e.g., to increase or decrease the distance between the open ends  46  before deploying the baskets  42 . 
     In one embodiment, the baskets  42  may be expandable from a contracted condition (not shown), e.g., sized for introduction through a patient&#39;s vasculature or other passages into a body lumen, and an expanded condition (shown in  FIG.  1   ), e.g., for capturing material within the open ends  46  of the baskets  42 . For example, the baskets  42  may be formed from elastic or superelastic material, such that the baskets  42  may be compressed radially inwardly to the contracted condition and resiliently expand towards the expanded condition. 
     Alternatively, the baskets  42  may be actuatable, i.e., selectively expanded and/or contracted using one or more actuators (not shown) on the proximal end of the apparatus  10 . For example, one or more balloons or other expandable members (not shown) may be provided on the core wire  22  within the baskets  42 . The balloon(s) may allow the baskets  42  to be expanded separately from one another and/or simultaneously depending upon the number of balloons and/or inflation lumens provided in the core wire  22 . 
     The middle portion  50  extends between the distal and proximal baskets  42   a ,  42   b  and has a cross-section that is smaller than the proximal and distal baskets in the expanded condition. As shown, the middle portion  50  is a tubular structure that includes opposite ends  52  coupled to the respective baskets  42 , e.g., by a plurality of struts  54 . For example, as shown in  FIG.  1   , the struts  54  may be coupled to the ends  52  of the middle portion  50  and adjacent the open ends  46  of the distal and proximal baskets  42   a ,  42   b . The struts  54  may be sufficiently flexible such that the middle portion  50  is movable laterally away from the central axis  38  relative to the distal and proximal baskets  42   l ,  42   b , for example, to accommodate receiving material within a body lumen between the baskets  42  adjacent the middle portion  50 , e.g., as shown in  FIG.  2 C . 
     In addition, the middle portion  50  may be substantially flexible such that the middle portion  50  is compressible axially, e.g., when the baskets  42  are moved towards one another for capturing material within the interiors of the baskets  42 . In addition or alternatively, the struts  54  may be substantially flexible to provide hinges that facilitate receiving the middle portion  50  within the interiors of the baskets  42  as the baskets  42  are moved towards one another. 
     The middle portion  50  may define a passage axially therethrough through which the core wire  22  may extend. Alternatively, the core wire  22  may extend along an exterior of or otherwise adjacent the middle portion  50 . 
     The wall  44  of the baskets  42  and/or the middle portion  50  may be porous or otherwise include a plurality of openings  47  therein, e.g., to allow fluid to flow around and/or through the baskets  42  during use. For example, the baskets  42  may be formed from one or more hypotubes or other tubular bodies that have portions of the bodies removed, e.g., by laser cutting, etching, mechanical cutting, and the like to define a plurality of struts  45  surrounding the openings  47 . For example, if the actuator member  24  is formed from a hypotube or other tubular material, the proximal basket  42   b  may be formed by cutting openings  47  and/or struts  45  in an end of the tubular material and then bending the resulting structure into the shape of the proximal basket  42   b . Similarly, the middle portion  50  may also be formed from a tubular body that has portions removed to create a plurality of struts surrounding openings in the middle portion  50 . 
     Alternatively, the baskets  42  and/or middle portion  50  may be made from one or more wires that are formed into a mesh structure, e.g., by welding, bonding, or otherwise attaching the wire(s) together to define the struts  45 . Exemplary materials for the baskets  42  include metals, such as Nitinol or stainless steel, polymers or other plastics, or composite materials. The baskets  42  may be heat treated or otherwise set to be biased to the expanded condition yet resiliently compressible to the contracted condition. For example, if the baskets  42  are formed by cutting openings  47  and/or struts  45  from individual tubular bodies having a cross-section similar to the contracted condition, the resulting structure may be expanded to the expanded condition and then heat treated to program the expanded condition into the material of the structure. 
     Optionally, if smaller apertures are desired, a covering (not shown) may be placed over or within one or both of the baskets  42 . Holes may be drilled, cut, or otherwise provided in the covering, e.g., using laser drilling, mechanical drilling, punching, and the like to provide a desired pore size. The covering may be attached to the basket(s)  42  by bonding with adhesive, heat fusion, sonic welding, interference fit, and the like. Alternatively, a non-porous covering may be provided if flow obstruction through the wall  44  of the basket(s)  42  is desired. 
     As shown in  FIG.  1   , the baskets  42  and middle portion  50  may be defined by a plurality of zigzag struts that extend circumferentially and/or axially around the basket device  40 . For example, alternating diagonal struts may be connected to one another about the circumference of the baskets  42  to define a zigzag band and adjacent bands may be attached or integrally formed together in an axially repeated pattern. For example the open ends  46  of the baskets  42  may define a zigzag pattern extending around a perimeter of the open ends  46 . In one embodiment, the zigzag patterns of at least the open ends  46   a ,  46   b  may be out of phase with one another such that the open ends  46  may at least partially intertwine with one another to substantially enclose the interiors of the baskets  42 , e.g., as described further below. 
     After forming the baskets  42  and middle portion  50 , the struts  54 , which may be integrally formed with the middle portion  50  or formed separately and attached to the ends  52  of the middle portion  50 , e.g., by welding, bonding, and the like, may be attached to the baskets  42  adjacent the open ends  46  using similar methods. It may be useful to attach the struts  54  extending from the ends  52  of the middle portion  50  adjacent the open ends  46  (rather than at the open ends  46  themselves) to allow the open ends  46  of the baskets  42  to remain free during use, e.g., when the baskets  42  are deployed and directed towards one another to capture material within the baskets  42 . 
     In exemplary embodiments, the baskets  42  may have a diameter between about half and two millimeters (0.5-2.0 mm) in the contracted condition and a diameter between about two and nine millimeters (2.0-9.0 mm) in the expanded condition. The middle portion  50  may have a diameter between about one and three millimeters (1-3 mm). For example, the middle portion  50  may have a diameter slightly smaller than the contracted condition, e.g., to accommodate overlap with the baskets  42 , and the diameter of the middle portion  50  may remain substantially constant upon expansion of the baskets  42 . Alternatively, the middle portion  50  may be radially compressed into a diameter substantially smaller than the contracted condition of the baskets  42  and may be expanded to a diameter smaller than the expanded condition of the baskets  42 . 
     As shown in  FIGS.  2 A and  2 B , the shaft  20  and/or basket device  40  may be carried within the sheath  30 , e.g., to facilitate delivery of the basket device  40  to a target site. The sheath  30  may include a proximal end (not shown), a distal end  34 , and a lumen  36  extending therebetween. Optionally, the sheath  30  may include one or more additional lumens (not shown) extending between the proximal end and the distal end  34 , e.g., for delivering and/or aspirating fluid via the distal end  34 , for receiving a guidewire or other rail (not shown), and the like. For example, in some applications, it may be desirable to advance the entire apparatus  10  over a guidewire or other rail (not shown), e.g., by loading the guidewire through a guidewire lumen (also not shown) disposed adjacent the lumen  36 . In addition, or alternatively, a source of fluid, e.g., one or more solvents or other therapeutic agents, a source of vacuum, e.g., a syringe, and the like, may be coupled to the sheath  30 . 
     For example, as described above, the apparatus  10  may include a handle (not shown), and the proximal end of the sheath  30  may be coupled to the handle such that the sheath  30  and/or the shaft  20  are movable axially relative to one another to accommodate deploying and/or recovering the basket device  40  during use. In addition, the handle may include one or more ports (also not shown) for being coupled to a source of fluid and/or vacuum. The port(s) may communicate with the lumen  36  (or other lumen, not shown, provided in the sheath  36 ). 
     During assembly or immediately before use, the shaft  20  and/or basket device  40  may be loaded into the lumen  36  of the sheath  30 , e.g., such that the basket device  40  is compressed into the contracted condition. For example, the shaft  20  may be backloaded into the sheath  30  until the baskets  42  are disposed adjacent the distal end  34  of the sheath. The baskets  42  may then be compressed into the contracted condition and directed into the lumen  36 , e.g., such that the baskets  42  are disposed adjacent the sheath distal end  34  with the distal tip  26  extending from the sheath  30 , as shown in  FIGS.  2 A and  2 B . An external constraint (not shown) may be used to compress the baskets  42  inwardly before being loaded into the sheath  30 . Alternatively, for at least the proximal basket  42   b , the closed end  48   b  may be tapered or otherwise shaped to allow the closed end  48   b  to slidably engage the sheath distal end  34 , thereby compressing the proximal basket  42   b  inwardly as the basket device  40  is pulled into the sheath  30 . 
     The proximal ends of the core wire  22 , actuator member  24 , and/or sheath  30  may be coupled to any other necessary components of the apparatus  10 , e.g., to a handle and/or actuator components, to provide an assembled apparatus  10  that may be provided to a user. 
     The baskets  42  (and/or middle portion  50 ) may be biased to resiliently expand to the expanded condition upon being deployed from the sheath  30 . For example, as each of the baskets  42  become exposed, e.g., first the distal basket  42   a  and then the proximal basket  42   b  (as described further below), the baskets  42  may automatically and sequentially open towards the expanded condition. Alternatively, the baskets  42  may be selectively expandable from the contracted to the expanded conditions, e.g., by activating an actuator on a proximal end of the apparatus  10 . 
     If desired, the apparatus  10  may include one or more markers to facilitate positioning and/or advancement of the apparatus  10  during use. For example, one or more radiopaque markers may be placed on the basket device  10 , e.g., on the open ends  46  of the baskets  42 . In addition or alternatively, such markers may be placed at one or more locations on the core wire  22 , shaft  24 , and/or sheath  40 . Alternatively, the basket device  10  or components thereof may be formed from radiopaque or other materials that may facilitate imaging the apparatus  10  during use. For example, radiopaque markers and/or materials may facilitate positioning or otherwise imaging the apparatus  10  using fluoroscopy or other x-ray imaging, e.g., when deploying and/or actuating the basket device  40 . Alternatively, echogenic markers and/or materials may be provided to facilitate imaging using ultrasound or similar imaging techniques. 
     Turning to  FIGS.  2 A- 2 E , an exemplary method is shown for retrieving, removing, or otherwise capturing material  90  within a body lumen  92 , e.g., using an apparatus  10 , which may be any of the embodiments described herein, and not necessarily limited to the embodiment shown and described below with reference to  FIG.  1   . The body lumen  92  may be a blood vessel, e.g., a vein or artery, a graft, e.g., an aorto-venous fistula, tubular xenograft, or synthetic tubular graft, and the like. For example, the body lumen  92  may be a passage communicating between an adjacent artery and vein (not shown), e.g., in an arm or other region of a dialysis patient. Alternatively, the body lumen  92  may be a blood vessel within a patient&#39;s vasculature, e.g., a peripheral vessel in a patient&#39;s leg, a cerebral vessel, and the like. In a further alternative, the material  90  may be a stone within a patient&#39;s urinary tract or other foreign object to be removed from the patient&#39;s body. 
     Optionally, the body lumen  92  may be accessed using one or more additional instruments (not shown), which may be part of a system or kit including the apparatus  10 . For example, an introducer sheath or other tubular member (not shown) may be introduced adjacent the target site where the material is to be removed, or may be introduced elsewhere in the patient&#39;s body to provide access to the patient&#39;s vasculature or other passages communicating with the body lumen  92 . If the body lumen  92  is located in a peripheral vessel of the patient, a percutaneous puncture or cut-down may be created using a needle or other instrument (not shown) at a peripheral location (also not shown), such as a femoral artery, carotid artery, or other entry site, and an introducer sheath may be placed through the puncture at the peripheral location to provide access. The apparatus  10  may be advanced through the patient&#39;s vasculature from the entry site, e.g., alone or with the aid of a guide catheter  80 , guidewire (not shown), and the like. 
     For example, to facilitate directing the apparatus  10  from an entry site to the target body lumen  92 , a guide catheter, micro-catheter, or other tubular body  80  may be placed from the entry site to the body lumen  92  using conventional methods. In addition or alternatively, a guidewire (not shown) may be placed from the entry site to the body lumen  92  if desired, e.g., if the apparatus  10  includes a guidewire lumen in the sheath  30  or core wire  22 . 
     Initially, as shown in  FIG.  2 A , the apparatus  10  has been advanced through the guide catheter  80  into the body lumen  92 . The apparatus  10  may be provided with the basket device  40  (not shown) compressed and/or retracted into the sheath  20 , i.e., in the contracted condition. For example, the basket device  40  may be placed within the sheath  20  during manufacturing or immediately before the procedure by the user. The relatively low profile of the sheath  30  and atraumatic distal tip  26  may facilitate advancing the apparatus  10  adjacent the material  90 , e.g., such that the distal tip  26  and distal end  34  of the sheath  30  may be advanced through or along and distally beyond the material  90 , as shown in  FIG.  2 B , without substantial risk of dislodging, breaking, or otherwise damaging the material  90 . 
     Optionally, the guide catheter  80  and/or sheath  30  may facilitate delivering one or more fluids into the body lumen  92 , e.g., to facilitate imaging and/or positioning the apparatus  10 . For example, radiopaque fluid may be delivered into the body lumen  92  via the guide catheter  80  (or via a lumen in the sheath  30 , actuator member  24 , or core wire  22 ) to facilitate locating and/or measuring the size of the material  90  using fluoroscopy. Markers (not shown) on the apparatus  10  may facilitate positioning the basket device  40  relative to the material  90  before deployment. For example, such markers may facilitate verifying that the basket device  40  is positioned with the distal basket  42   a  distal to the material  90  and the proximal basket  42   b  proximal to the material  90 , e.g., with the material adjacent the middle portion  50 , as shown in  FIGS.  2 B and  2 C , before deployment. If desired, the spacing of the distal and proximal baskets  42   a ,  42   b  may be adjusted based upon the size of the material  90  encountered. For example, if the length of the material  90  is greater than the initial spacing of the baskets  42  within the sheath  30 , the core wire  22  or actuator member  24  may be directed axially to increase the spacing between baskets  42  to ensure that the open ends are located proximally and distally sufficiently from the material  90  upon deployment. 
     The basket device  40  may then be deployed within the body lumen  92 , e.g., such that the material to be removed or captured is disposed within or adjacent the basket device  40 , as shown in  FIG.  2 C . For example, the sheath  30  may be retracted, thereby deploying the distal basket  42   a  beyond the material  90  and then deploying the proximal basket  42   b  proximal to the material  90 . As described above, the baskets  42  may resiliently and/or automatically expand upon being exposed within the body lumen  92 . In addition or alternatively, the baskets  42  may be selectively expanded within the body lumen  92 . For example, a balloon or other expandable member (not shown) may be expanded to expand the baskets  42  independently of one another or simultaneously. In the expanded condition, the open ends  46  may substantially engage or contact the wall of the body lumen  92 , e.g., to prevent material  90  captured between the proximal and distal baskets  42  from being released. 
     As shown, the middle portion  50  of the basket device  40  may be disposed adjacent the material  90  upon deployment, e.g., being pushed laterally to one side of the body lumen  92  by the material  90 . For example, the struts  54  connecting the middle portion  50  to the baskets  42  may bend or otherwise provide sufficient flexibility to accommodate this lateral movement of the middle portion  50 , if desired. The openings in the middle portion  50  may partially capture or engage the material  90 , e.g., to at least partially secure the material  90  to the middle portion  50 , which may reduce the risk of material  90  breaking free from the basket device  40 . Optionally, if desired, the middle portion  50  may include other structures and/or materials, e.g., strands, fibers, and the like (not shown), in addition to or instead of the tubular structure shown, which may enhance securing the material  90  to the middle portion  50 . 
     Turning to  FIG.  2 D , if desired, the material  90  may be treated, e.g., at least partially dissolved, macerated, and the like before or after actuation of the basket device  40 . For example, a therapeutic agent may be delivered into the body lumen  92  via the guide catheter  80  (or an infusion lumen in one of the members of the apparatus  10 ). The middle portion  50  of the basket device  40  may ensure a passage through and/or beyond the material  90 , which may enhance treatment of the material  90  along its entire length within the body lumen  92 . The porous, open configuration of the basket device  40  may also facilitate such treatment of the material  90 . For example, if the material  90  is thrombus or other relatively soft material, the material  90  may be compressed within the basket device  40  such that portions of the material  90  pass through the openings  47  in the basket device  40 . This may increase exposed surface area of the material  90  increasing the effectiveness of any therapeutic agent introduced into the body lumen  92 . Optionally, vacuum may be applied via the guide catheter  80  (or one of the members of the apparatus  10 ), e.g., to aspirate any therapeutic agent(s), dissolved or separated material  90 , and the like, before or after actuating the basket device  40 . 
     In addition, if the middle portion  50  is a tubular structure, the middle portion  50  may provide a flow passage across the material  90 . For example, if the material  90  is clot, thrombus, and the like partially or entirely obstructing the body lumen  92 , deployment of the middle portion  50  may immediately provide a flow path for blood across the material  90 . Such blood flow may reduce or eliminate an ischemic condition of tissues downstream from the obstruction or provide other immediate benefit to the patient. 
     Turning to  FIG.  2 E , the basket device  40  may then be actuated to capture the material  90  within the baskets  42 , e.g., to minimize liberation of the material  90  during removal. For example, the core wire  22  may be directed proximally, thereby pulling the distal basket  42   a  towards the proximal basket  42   b , e.g., until the open ends  46  contact or are otherwise disposed immediately adjacent one another. Alternatively, the actuator member  24  may be directed distally to push the proximal basket  42   b  distally towards the distal basket  42   a . As shown, the zigzag shapes of the open ends  46  are offset from one another such that the baskets  42  may engage or become entwined with one another to enhance entrapment of the material  90  within the basket device  40 . Optionally, the open ends  46  may include detents or other features that may lock or otherwise secure the open ends  46  together to prevent subsequent separation of the baskets  42 . The struts  54  and/or the middle portion  50  may bend or otherwise deform to facilitate receiving the middle portion  50  within the interiors of the baskets  42  along with the material  90  captured therein. 
     The apparatus  10  may then be withdrawn from the body lumen  92  along with the material  90  captured within the basket device  40 . For example, the apparatus  10  may be pulled until the proximal basket  42   b  contacts the guide catheter  80 , whereupon the guide catheter  80  and apparatus  10  may be withdrawn from the body lumen  92  and/or entirely from the patient&#39;s body. Alternatively, the apparatus  10  may be directed such that the basket device  40  at least partially enters the guide catheter  80 . For example, the closed end  48   b  of the proximal basket  42   b  may be tapered, as shown, thereby causing the proximal basket  42   b  to compress radially inwardly towards the contracted condition as it is directed into the guide catheter  80 . If the open ends  46  of the baskets  42  are sufficiently entwined, as the proximal basket  42   b  is compressed, the distal basket  42   a  may also become compressed, thereby allowing the entire basket device  40  to be compressed and pulled into the guide catheter  80  with the material  90 . 
     In addition or alternatively, a source of aspiration may be coupled to the guide catheter  80  and activating to pull the captured material  90  into the guide catheter  80  and from the patient&#39;s body. For example, the aspiration may pull the material  90  through the openings  47  in the basket device  40 , thereby breaking the material  90  into smaller portions that may be more easily drawn into the guide catheter  80 . This aspiration may also be enhanced by delivering a solvent or other therapeutic agent via the guide catheter  80  to further break up or dissolve the material  90 . 
     With the material  90  aspirated and/or the basket device  40  partially or entirely withdrawn into the guide catheter  80 , the guide catheter  80  and any remaining components of the apparatus  10  may be removed from the body lumen  92  and/or the patient&#39;s body. The process may be repeated, as desired, using the same apparatus  10  or a different apparatus (not shown). For example, the basket device  40  may be withdrawn into the sheath  30  and then directed to another location within the body lumen  92  or other elsewhere, and then redeployed to capture additional material, and the process may be repeated as often as desired. Alternatively, another apparatus  10  may be introduced into the body lumen  92  or other location before closing the entry site, as desired. 
     Turning to  FIGS.  3 - 4 D , another embodiment of an apparatus  110  is shown for removing, retrieving, or otherwise capturing material within a body lumen. Generally, the apparatus  110  includes an expandable basket device  140  carried by a shaft or other elongate member  120 , and a sheath, micro-catheter, or other tubular member  130  (not shown, see, e.g.,  FIGS.  5 A- 5 E ) for facilitating delivery and/or removal of the shaft  120  and basket device  140 , similar to the previous embodiments. For example, the shaft  120  includes a core wire  122  and an actuator member  124  disposed adjacent the core wire  122  that are movable axially relative to one another. The core wire  122  may be a substantially flexible elongate member terminating in a distal tip  126 , and the actuator member  124  may be an elongate tubular body including a proximal end (not shown), a distal end  128  having a size for introduction into a body lumen, and a lumen  129  for slidably receiving the core wire  122  therein, e.g., also similar to the previous embodiments. 
     The basket device  140  carried by the shaft  120  generally includes a distal basket  142   a  adjacent the distal tip  126 , and a proximal basket  142   b  proximal to and spaced apart from the distal basket  142   a . For example, the distal basket  142   a  may be attached to or otherwise fixed axially relative to the core wire  122 , e.g., adjacent the distal tip  126 , and the proximal basket  142   b  may be attached to or otherwise fixed axially relative to the actuator member  124 , e.g., to the distal end  128 . 
     As shown in  FIG.  3   , each of the baskets  142  includes a circumferential wall  144  defining an open end  146  communicating with an interior of the basket  142  and a closed end  148  attached to the core wire  122  or actuator member  124 . The open ends  144  are oriented towards one another and initially spaced apart from one another, as shown in  FIG.  3   , and the closed ends  148  are oriented away from one another. When the actuator member  124  and core wire  122  are moved axially relative to one another, one or the baskets  142  may be moved towards the other for substantially enclosing the interiors of the baskets  142 , e.g., as shown in  FIGS.  4 A- 4 D  and described further below. 
     Also similar to the previous embodiment, the baskets  142  may be expandable from a contracted condition (not shown), e.g., sized for introduction through a patient&#39;s vasculature or other passages into a body lumen, and an expanded condition (shown in  FIG.  3   ), e.g., for capturing material within the interiors of the baskets  142 . For example, the baskets  142  may be formed from elastic or superelastic material, such that the baskets  142  may be compressed radially inwardly to the contracted condition and resiliently expand towards the expanded condition, similar to the previous embodiments. 
     The wall  144  of the baskets  142  may be porous or otherwise include a plurality of openings  147  therein, e.g., to allow fluid to flow around and/or through the baskets  142  during use, similar to the previous embodiments. For example, as best seen in  FIGS.  5 C- 5 F , the baskets  142  may include a plurality of struts  145  surrounding openings  147 . The baskets  142  may be formed from one or more hypotubes or other tubular material, e.g., by laser-cutting or otherwise removing material to define the struts  145  and openings  147 , or formed from one or more wires that are cut, bent, or otherwise formed into the desired mesh structure for the baskets  142   b , similar to the previous embodiments. 
     Unlike the previous embodiments, the distal basket  142   a  includes one or more elements  150  extending from the open end  146   a  to a collar  152  slidable on the core wire  122 . For example, the elements  150  may include a plurality of struts extending from the open end  146   a  longitudinally along the inside of the wall  144   a  of the distal basket towards the closed end  148   a , and then bending or curving inwardly to the collar  152 . As shown, the elements  150  include at least two struts spaced apart about the circumference of the distal basket  142   a , although only one or several struts may be provided, as desired. Thus, the elements  150  may couple the open end  146   a  to the collar  152  without substantially obstructing the interior of the distal basket  142   a . Alternatively, the elements  150  may extend diagonally or radially inwardly (not shown) from the open end  146   a  to the collar  152 , as long as the elements  150  allow the distal basket  142   a  to be compressed and expanded between the contracted and expanded conditions. 
     The collar  152  may be slidable disposed around the core wire  122 , while the closed end  148   a  of the distal basket  142   a  is substantially fixed to the core wire  122 . Thus, the collar  152  may be slidable distally towards the closed end  148   a  to direct the open end  146   a  radially inwardly, as described further below. 
     In one embodiment, the distal basket  142   a , elements  150 , and collar  152  may be integrally formed from a single structure, e.g., a laser-cut tube with the collar  152  and elements  150  initially extending axially beyond the open end  146   a  of the distal basket  142  (not shown). The collar  152  and elements  150  may then be bent or otherwise deformed to position the collar within the interior of the distal basket  142   a  and the elements along the inside of the wall  144   a , and the material heat treated or otherwise to program the desired shape. Alternatively, the collar  152 , elements,  150 , and/or distal basket  142   a  may be formed from separate components that are attached together, e.g., by welding, bonding, and the like. 
     Also unlike the previous embodiments, the proximal basket  142   b  is attached to the actuator member  124  proximal to the distal end  128 . For example, as shown in  FIG.  3   , the closed end  148   b  of the proximal basket  142   b  may be attached to the actuator member  124  proximal to the distal end  128  of the actuator member  124 , e.g., such that the distal end  128  extends distally at least partially through the interior of the proximal basket  142   b . Alternatively, a separate tubular member or other feature (not shown) may be attached to the closed end  148   b  of the proximal basket  142   b  and/or to the distal end  128  of the actuator member  124  such that the feature extends axially through the proximal basket  142   b . The distal  128  (or separate feature) may extend distally over the core wire  122  through the interior of the proximal basket  142   b  towards the interior of the distal basket  142   a . For example, as shown in  FIG.  3   , the distal end  128  of the actuator member  124  may extend into the interior of the distal basket  142   a  such that the distal end  128  is adjacent but spaced apart from the collar  152 . 
     Turning to  FIGS.  4 A- 4 D , the distal end  128  of the actuator member  124  and collar  152  may provide a mechanism for compressing the open end  146   a  of the distal basket  142   a  during use. For example, as shown in  FIG.  4 A , the distal end  128  of the actuator member  124  may be spaced apart from the collar  152  by a distance that is less than the distance between the open ends  146  of the distal and proximal baskets  142 . Although the open ends  146  of the baskets  142  are shown to be relatively close to one another compared to the length of the baskets  142 , it will be appreciated that the spacing is not shown to scale, and that the open ends  146  may be spaced apart any desired distance, e.g., to accommodate receiving material between the baskets  142  during use, as described elsewhere herein. 
     As shown in  FIG.  4 B , when the core wire  122  is pulled proximally relative to the actuator member  124  (or the actuator member  124  is advanced distally) to direct the baskets  142  towards one another, the distal end  128  and collar  152  may contact one another before the open ends  146  of the baskets  142  contact one another, i.e., the open ends  146  may yet be spaced apart from one another. As the core wire  122  or actuator member  124  is actuated further, the distal end  128  may contact the collar  152  and cause the collar  152  to be directed towards the closed end  148   a  of the distal basket  142   a , as shown in  FIG.  4 C . This action applies tension to the elements  150  coupled to the open end  146   a  of the distal basket  142   a , thereby applying a radially inward force on the open end  146   a.    
     As shown, thinned or weakened regions, hinges, or other bend features  154  may be provided on the struts of the distal basket  142   a  adjacent to the open end  146   a . For example, the struts defining the circumferential wall  144   a  of the distal basket  142   a  may have their width and/or thickness reduced relative to the other struts, e.g., by machining, etching, and the like. These preferential bend features  154  may cause the distal basket  146   a  to bend inwardly at these features  154 , as shown in  FIG.  4 C . Alternatively, if no bend features  154  are provided, the distal basket  142   a  may bend inwardly at other locations along the circumferential wall  144   a , e.g., at the transition between the closed end  148   a  and the circumferential wall  144   a  (not shown). Thus, the deformation of the distal basket  142   a  may be distributed along its longitudinal length, or it may be concentrated at the preferential bend features  154 . 
     Turning to  FIG.  4 D , as the core wire  122  or actuator member  124  are actuated further, the axial positions of the baskets  142  continue to converge, and as the open end  146   a  of the distal basket  142  deforms radially inward, the open ends  146  begin to overlap. For example, the open end  142   a  of the distal basket  142  may be deformed radially inwardly until it contacts the actuator member  124 , although the open end  142   a  may be spaced radially away from the actuator member  124 , if desired. As shown, the degree of inward radial deformation of the open end  146   a  of the distal basket  142   a  may be sufficient such that the open end  142   a  may extend into the open end  146   b  of the proximal basket  142   b . In doing so, the edges of the open end  146   a  of the distal basket  142   a  may be presented as the basket device  140  is retracted, e.g., into the delivery sheath  130  (see, e.g.,  FIGS.  5 A- 5 E ), guide catheter  80 , or other device, and/or removed from the body lumen  92  and/or the patient&#39;s body. 
     In addition, the overlap of the proximal basket  142   b  partially over the distal basket  142   a  may facilitate directing the basket device  140  back to the contracted condition, e.g., to facilitate removal. For example, if the basket device  140  in the configuration shown in  FIG.  4 D  is retracted into the guide catheter  80 , as shown in  FIG.  5 F  (or, alternatively, into the delivery sheath  130  or other device, not shown), the closed end  148   b  of the proximal basket  142   b  may be tapered to allow the proximal basket  142   b  to be compressed radially inwardly as it is drawn into the guide catheter  80 . The open end  146   b  of the proximal basket  142   b  may press inwardly against the open end  146   a  of the distal basket  142   a , thereby causing the distal basket  142   a  to also be compressed radially inwardly. Optionally, the baskets  142  may be compressed inwardly back to the original contracted condition or other size sufficiently small to allow withdrawal partially or entirely into the guide catheter  80 . 
     Turning to  FIGS.  5 A- 5 F , an exemplary method is shown for retrieving, removing, or otherwise capturing material  90  within a body lumen  92  using the apparatus  110 . Similar to the previous methods, the material  90  may be a foreign body, or a result of undesirable biological processes such as thrombus within the vasculature or stones within the urinary tract. 
     Initially, as shown in  FIG.  5 A , the apparatus  110  is provided within the basket device  140  (not shown, see  FIGS.  5 C- 5 F ) within the sheath  130  in the contracted condition. The apparatus  110  has been advanced through a guide catheter  80  into the body lumen  92  such that the distal tip  126  is adjacent the material  90 . Turning to  FIG.  5 B , the apparatus  110  may be advanced at least partially past the material  90 , e.g., such that the distal tip  126  and the distal basket  142   a  (not shown) within the sheath  130  is positioned distally beyond the material  90 . Similar to the previous embodiments, the relatively low profile of the sheath  130  and atraumatic distal tip  126  may facilitate advancing the apparatus  100  adjacent or through the material  90  without substantial risk of dislodging, breaking, or otherwise damaging the material  90 . 
     Optionally, the guide catheter  80  and/or sheath  130  may facilitate delivering one or more fluids into the body lumen  92 , e.g., to facilitate imaging and/or positioning the apparatus  110  and/or material  90 , similar to the previous embodiments. For example, markers (not shown) may be provided on the apparatus  110  to facilitate positioning the basket device  140  relative to the material  90  before deployment, also similar to the previous embodiments. 
     Turning to  FIG.  5 C , the basket device  140  may then be deployed within the body lumen  92 , e.g., such that the material to be removed or captured is disposed within or adjacent the basket device  140 . For example, with the distal end  134  of the sheath  130  disposed adjacent or distally beyond the material, the core wire  122  may be advanced, thereby deploying the distal basket  142   a  beyond the material  90 . With the proximal basket  142   b  remaining within the sheath  130 , the apparatus  110  may be manipulated further, e.g., to position the distal basket  142   a  immediately adjacent the material  90  and/or with the material  90  at least partially captured within the open end  146   a  of the distal basket  142   a.    
     The proximal basket  142   b  may then be deployed proximal to the material  90 , e.g., by retracting the sheath  130  or advancing the actuator member  134 . As described above, the baskets  142  may resiliently and/or automatically expand upon being exposed within the body lumen  92 . In the expanded condition, the open ends  146  may substantially engage or contact the wall of the body lumen  92 , e.g., to prevent material  90  captured between the proximal and distal baskets  142  from being released. 
     As can be seen in  FIG.  5 D , the core wire  122  extends through the interior of the distal basket  142   a  with the collar  152  free to slide along the core wire  122  to accommodate expansion of the open end  146   a  of the distal basket  142   a . The distal end  128  of the actuator member  124  is spaced substantially away from the collar  152 , i.e., proximally beyond the open end  146   a  of the distal basket  142   a  since the proximal basket  142   b  is positioned a substantial distance proximal to the distal basket  142   a . As shown, the core wire  122  may be disposed in a generally concentric position with respect to the body lumen  92  and the baskets  142 . Alternatively, if desired, the core wire  122  may be positioned in an eccentric position, e.g., by modifying the shape of the closed ends  148  of the baskets  142 , such that the core wire  122  extends along one side of the walls  144  of the baskets  142  (not shown). 
     Turning to  FIG.  5 E , the basket device  140  may then be actuated to capture the material  90  within the baskets  142 , e.g., to minimize liberation of the material  90  during removal. For example, the actuator member  124  may be advanced distally to direct the proximal basket  142   b  distally towards the distal basket  142   a , e.g., to capture material  90  within the interior of the baskets  142 . In particular, with additional reference to  FIGS.  4 A- 4 D , the actuator member  124  may be advanced until the distal end  128  of the actuator member  122  contacts and pushes the collar  152  distally, thereby compressing the open end  146   a  of the distal basket  142   a  radially inwardly and into the open end  146   b  of the proximal basket  14   b . Thus, as shown in  FIG.  5 E , as a result, the material  90  may be substantially captured within the baskets  142  to minimize risk of release of the material  90 . 
     Finally, as shown in  FIG.  5 F , the apparatus  110  may then be withdrawn from the body lumen  92  along with the material  90  captured within the basket device  140 . For example, as shown, the apparatus  110  may be pulled until the basket device  140  is at least partially received within the guide catheter  80 . As the proximal basket  142   b  contacts the guide catheter  80 , the proximal basket  142   b  may be compressed radially inwardly towards the contracted condition as it is pulled into the guide catheter  80 . As this motion continues, the distal basket  142   a  may also be withdrawn into the guide catheter  80  without hanging up because the leading edge of the open end  146   a  is contained within the proximal basket  142   b , and thus does not present any sharp or blunt edges. Furthermore, none of the struts or leading edges of the open end  146   a  of the distal basket  142   a  are likely to protrude through the openings  147   b  of the proximal basket  142   b  because they are radially deformed inwardly toward the core wire  122 . 
     The guide catheter  80  with the apparatus  110  therein may be withdrawn from the body lumen  92  and entirely from the patient&#39;s body with the baskets  142  completely contained within the guide catheter  80 . Alternatively, if desired, the basket device  140  may only be partially withdrawn into the guide catheter  80  before removal from the patient&#39;s body. In a further alternative, the apparatus  110  may be removed from the body lumen  92  and/or entirely from the patient&#39;s body without withdrawing the basket device  140  into the guide catheter  80 . In this alternative, bending and capturing the open end  146   a  of the distal basket  142   a  within the proximal basket  142   b  may ensure that no blunt or sharp edges are presented on the leading edge of the distal basket  142   a , which may facilitate retracting the apparatus  110  through other devices (such as an arterial access introducer sheath, not shown) or otherwise along the delivery path through the patient&#39;s vasculature, e.g., along various body lumens and/or tissue punctures through which the apparatus  110  was originally tracked when accessing the target body lumen  92 . 
     Optionally, one or more therapeutic agents may be delivered and/or fluid may be aspirated at any time via the guide catheter  80  or component of the apparatus  110 , similar to the previous embodiments. 
     It will be appreciated that elements or components shown with any embodiment herein are exemplary for the specific embodiment and may be used on or in combination with other embodiments disclosed herein. 
     While the invention is 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 the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.