Abstract:
A coupling wire guide structured to be slidably coupled to a previously introduced wire guide. The coupling wire guide includes a main body having a distal section. The distal section includes an outer wire disposed over a safety wire. A loop wire is connected to the safety wire at two axially spaced points. At least a portion of the loop wire is positioned outside of the outer wire to define a loop area sized to receive the previously introduced wire guide.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/758,880 filed on Jan. 13, 2006, entitled “WIRE GUIDE HAVING DISTAL COUPLING TIP”, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates generally to a wire guide for use in intracorporeal procedures, and more particularly relates to the construction of a wire guide to be coupled to a previously introduced wire guide for assistance during interventional procedures in vessels with proximal tortuosity, or as a more substantial wire guide for angioplasty procedures, stenting procedures, and other device placement procedures and their related devices.  
       BACKGROUND OF THE INVENTION  
       [0003]     Proximal tortuosity of the vasculature is problematic for all medical catheter devices such as atherectomy devices, angioplasty devices, stent delivery devices, and filter delivery devices. Wire guides are therefore typically used to navigate the vasculature of a patient during percutaneous interventional procedures. Once the wire guide has been introduced, it may then be used to introduce one or more medical catheter devices. Thus, most wire guides are typically 0.014 inches in diameter and have a lubricious coating to enhance wire guide introduction movement. Conventional 0.014 inch floppy wire guides must have sufficient flexibility and torque control for navigation through tortuous vessels. At the same time, the wire guide must have a certain amount of rigidity to pass through lesions, straighten extremely tortuous vessels, and support medical catheter devices that are introduced over the wire guide.  
         [0004]     Accordingly, wire guides are subjected to potentially conflicting requirements. Conventional 0.014 inch floppy wire guides are usually sufficient for navigation of moderately tortuous vessels. However, in some situations the wire guide tip may prolapse away from the site to which it is guiding the device. For example, balloon angioplasty in vessels with proximal tortuosity has been associated with a higher incidence of acute complications and procedural failure due to the inability to cross lesions with a conventional floppy wire guide, and due to the inability of the wire guide to provide adequate support to the balloon catheter. Heavy-duty wire guides, on the other hand, are generally not well suited as primary wire guides because of their stiffness and potential for causing injury to the vessel during introduction.  
         [0005]     It may therefore be desirable to use conventional floppy wire guides for navigation of tortuous vessels, and then enhance the conventional wire guide with a supplemental wire guide. The supplemental wire guide will straighten out the vessel curves and ease further wire guide movement. Additionally, the supplemental wire guide provides greater support and enhances the tracking of balloons, stents, stent delivery devices, atherectomy devices, and other medical catheter devices as compared to a conventional floppy wire guide. This technique is commonly referred to as the “Buddy Wire” technique, details of which are disclosed in U.S. patent application Ser. No. 11/081,146, filed Mar. 16, 2005.  
         [0006]     However, the navigation of the supplemental wire guide parallel to the first wire guide is an exacting and time consuming process in which additional difficulties are encountered. For example, the second wire guide can cork screw or coil around the first wire guide, which may result in immobilization or unintended movement of the first wire guide, which in turn may require the retraction and re-feeding of the supplemental wire guide and/or the primary wire guide. Moreover, if retraction of the supplemental wire guide is necessary, either of the wire guides may become contaminated and the entire process may need to be restarted with sterile components. The time consumed by this process can be critical to the success of the procedure. Additionally, when traversing through the heart of a patient, and particularly the ostium, the larger open space of the heart makes identical placement of the supplemental wire guide somewhat difficult.  
         [0007]     Accordingly, there exists a need to provide a supporting wire guide for intracorporeal procedures that may be easily and reliably traversed through the vasculature to a position proximate a previously introduced wire guide.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a supporting wire guide for intracorporeal procedures that may be easily and reliably traversed through a body lumen to a position proximate a previously introduced wire guide. The supporting wire guide is a coupling wire guide that is structured to be slidably coupled to the previously introduced wire guide. In one embodiment constructed in accordance with the teachings of the present invention, the coupling wire guide generally includes a main body and a tip portion connected to the distal end of the main body. The tip portion includes a coupling head defining a coupling passageway. The coupling head is operable between at least two positions including a first position generally aligned with the main body and a second position non-aligned with the main body.  
         [0009]     According to more detailed aspects of the invention, the tip portion is preferably constructed of a resilient material, and most preferably a plastic overmolded onto the distal end of the main body. The tip portion includes a neck connected to the coupling head which flexes to permit the coupling head to transition between the first and second positions. The neck has an outer diameter that is less than the outer diameter of the coupling head, and preferably includes one or more radially facing depressions to create a predetermined path along which the coupling head flexes between the first and second positions. An outer diameter of the coupling head is about equal to or less than the largest diameter of the remainder of the tip portion, thereby improving placement and translation of the coupling wire guide when not coupled to a previously introduced wire guide.  
         [0010]     According to another aspect of the invention, the coupling head is biased towards the first position. The coupling passageway is generally parallel to the distal end of the main body in the second position to promote smooth translation along the previously introduced wire guide. The coupling passageway defines a passageway axis while the main body includes a central axis. In the first position, the passageway axis is angled relative to the central axis, and in the second position, the passageway axis is generally parallel with the central axis. Preferably, the passageway axis is angled less than 45 degrees relative to the central axis when in the first position.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:  
         [0012]      FIG. 1  is a perspective view of a coupling wire guide constructed in accordance with the teachings of the present invention;  
         [0013]      FIG. 2  is a cross-sectional view of the coupling wire guide shown in  FIG. 1 ;  
         [0014]      FIG. 3  is another cross-sectional view of the coupling wire guide shown in  FIG. 1 ;  
         [0015]      FIG. 4  is a cross-sectional view of another coupling wire guide constructed in accordance with the teachings of the present invention;  
         [0016]      FIG. 5  is a different cross-sectional view of the coupling wire guide shown in  FIG. 4 .  
         [0017]      FIG. 6  is a cross-sectional view of another coupling wire guide constructed in accordance with the teachings of the present invention; and  
         [0018]      FIG. 7  is a different cross-sectional view of the coupling wire guide shown in  FIG. 6 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Turning now to the figures, FIGS.  1  to  3  depict a coupling wire guide  20  constructed in accordance with the teachings of the present invention. The coupling wire guide  20  is easily and reliably coupled to and traversed along a previously introduced wire guide  10 , and also is easily used alone by maintaining a relatively low profile when decoupled. While wire guides are generally used in percutaneous interventional procedures, it will be recognized by those skilled in the art that the wire guide of the present invention may also be employed non-percutaneously, such as in endoscopic or other intracorporeal procedures. As best seen in  FIG. 1 , the coupling wire guide  20  generally includes a main body  22  and a tip portion  24 . The tip portion includes an attachment section  26 , a neck  28  and a coupling head  30 . The coupling head  30  defines a coupling passageway  32  having a distal port  34  and a proximal port  36  through which the previously introduced wire guide  10  passes, as shown in  FIG. 3 .  
         [0020]     As best seen in  FIGS. 2 and 3 , the main body  22  generally comprises a coiled wire  38  disposed over a mandrel  40 , a structure well known in the art. It will be recognized that the previously introduced wire guide  10 , as well as the main body  22  of the coupling wire guide  20 , may take numerous forms as many types of wire guides are known in the art, including solid wire, tubular wires, coiled wires and combinations thereof. For example, U.S. Pat. No. 5,243,996 discloses an exemplary solid wire mandrel having a coil tip section.  
         [0021]     A distal end  42  of the main body  22  is connected to the attachment section  26  of the tip portion  24 . The methods and materials used to inter-connect attachment section  26  and distal end  42  will vary depending upon the configuration and type of material utilized for the main body  22  and the tip portion  24 . In the figures, the tip portion  24  and its attachment section  26  have been depicted as a plastic material, and preferably a biocompatible thermoplastic which may be injection molded. Preferable materials include polytetrafluorethylene (PTFE), expanded polytetrafluorethylene (EPTFE), polyethylene ether ketone (PEEK), polyvinylchloride (PVC), polyamide including Nylon®, polyimide, polyurethane, polyethylene (high, medium or low density), and elastomers such as Santoprene®, including multi-layer or single layer constructions with or without reinforcement wires, coils or filaments. In this manner, the attachment section  26  may be overmolded directly onto the distal end  42  of the main body  22 . It will be recognized that in the overmolding process, the plastic material forming the attachment section  26  will be allowed to flow in between and around the coils of wire  38  to provide a secure inter-connection of the main body  22  and tip portion  24 .  
         [0022]     As noted above, many different attachment methods and materials may be used depending on the particular materials utilized. For example when the tip portion  24  is formed of a metal such as stainless steel or nitinol (Ni—Ti superelastic alloy), or when the attachment section  26  is formed of this material, the attachment section  26  may be soldered or welded to the distal end  42 , or may inter-connected through other mechanical means such as clamping, latching, fasteners, material deformation techniques and the like.  
         [0023]     The tip portion  24  includes a neck  28  linking the attachment section  26  to the coupling head  30 . The neck  28  preferably includes a first radially facing depression  44  and a second radially facing depression  46 . The neck thus has an outer diameter less than an outer diameter of the coupling head  30 . The neck  28  is constructed of a resilient but flexible material such that the coupling head  30  may take a decoupled or first position depicted in  FIG. 2 , but yet may be rotated, pivoted, or otherwise transitioned to a second position depicted in  FIG. 3 . The shape of the neck  28  and particularly the depressions  44 ,  46  assist in providing this flexibility and determining the path of transition between the first and second positions depicted in  FIGS. 2 and 3 , respectively. Specifically, these depressions  44 ,  46  may take various sizes and shapes to determine the path followed by the head  30  between the first and second positions.  
         [0024]     Generally, the coupling head  30  is aligned with the main body  22  in the first position ( FIG. 2 ), and is generally non-aligned (and offset from) the main body  22  in the second position ( FIG. 3 ). That is, the coupling head  30  is generally in-line with a central axis  23  of the main body  22  in the first position, but is positioned radially away from the central axis  23  in the second position. The first depression  44  faces away from the second position ( FIG. 3 ) of the coupling head  30 , while the second depression  46  faces towards the second position of the coupling head  30 . Due to the resilient nature of the neck  28  and coupling head  30 , the coupling head  30  is generally biased towards the first position when decoupled from a previously introduced wire guide  10 . Further, the outer diameter of the coupling head  30  is about equal to or less than the largest diameter of the remainder of the tip portion  24 , namely the attachment section  26 . As such, the coupling wire guide  20  is easily used as a single wire guide having a coupling tip portion  24  that is generally aligned with the main body  22  while maintaining a consistent profile or outer diameter.  
         [0025]     Notably, in the second position ( FIG. 3 ), the coupling passageway  32  takes a position which eases transition of the coupling wire guide  20  along the previously introduced wire guide  10 . It can be seen that the coupling passageway  32  is positioned radially outside the distal end  42  of the main body  22  in the second position. In the first position ( FIG. 2 ), the coupling passageway  32  defines a passageway axis  33  which is angled relative to the central axis  23  of the main body  22 . Preferably, this angle is less than 45 degrees and most preferably about 15 to 30 degrees such that the coupling head  30  only needs to rotate about 45 degrees or less to the second position. In the coupled or second position shown in  FIG. 3 , the passageway axis  33  is generally parallel with the central axis  23  of the main body  22 . By the term generally parallel, it is meant that the axes or bodies are parallel within 5 degrees of one another. In this manner, the tip portion  24  bends to meet the previously introduced wire guide  10 , rather than forcing the previously introduced wire guide  10  to itself bend into the passageway  32  formed by the previously introduced wire guide  20 . Accordingly, the coupling wire guide  20  may be translated in a generally parallel fashion along the previously introduced wire guide  10  while minimizing any deformation or bending of the previously introduced wire guide  10 .  
         [0026]     Another embodiment of a coupling wire guide  120  is depicted in  FIGS. 4 and 5 . Similar to the prior embodiment, the coupling wire guide  120  includes a main body  126  and a tip portion  124 . The tip portion  124  includes an attachment section  126 , a neck  128  and a coupling head  130  which transitions between a first position depicted in  FIG. 4  and a second coupling position depicted in  FIG. 5 . The coupling head  130  defines a coupling passageway  132  having an axis  133  which is angled relative to the central axis of the main body  122  in the first position, but generally parallel to the central axis in the second position. The main body  122  again includes an outer wire  138  disposed over a inner mandrel  140 , and having a distal end  142  which is connected to the attachment section  126  of the tip portion  124 .  
         [0027]     In this embodiment of the coupling wire guide  120 , the neck  128  includes first and second depression  144 ,  146  much like the prior embodiment, however the first depression  144  generally faces the second position of the coupling head  130 . That is, the coupling passageway  132  opens towards the larger first depression  144 , thereby providing greater access to the proximal port  136 . At the same time, the neck  128  must provide greater flexibility and the coupling head  130  must bend a bit more than the prior embodiment, although the angled rotation of the passageway  132  is somewhat less than the prior embodiment. It will be recognized by those skilled in the art that numerous embodiments of the present invention are possible, both through the use of materials different than those described here, as well as through numerous shapes and orientations of the coupling tip and its pivoting head.  
         [0028]     Another embodiment has been depicted in  FIGS. 6 and 7 . As with the previous embodiments, the coupling wire guide  220  generally includes a main body  222  and a tip portion  224 . The tip portion  224  includes an attachment section  226 , a neck  228  and a coupling head  230 . The coupling head  230  defines a coupling passageway  232  having a distal port  234  and a proximal port  236  through which the previously introduced wire guide  210  passes, as shown in  FIG. 7 . The main body  222  of the coupling wire guide  220  generally comprises a coiled wire  238  disposed over a mandrel  240 . A distal end  242  of the main body  222  is connected to the attachment section  226  of the tip portion  224 . The neck  228  of the tip portion  224  links the attachment section  226  to the coupling head  230 . The neck  228  again includes a first radially facing depression  244  and a second radially facing depression  246 .  
         [0029]     In this embodiment, the neck  228  is reinforced with a securing member  241 . As shown, the securing member  241  is an extension of the mandrel  240 . That is, the distal end of the mandrel  240  has been formed with a reduced diameter portion that protrudes beyond the outer coiled wire  238 , and over which the tip portion  224  is formed. As shown, the securing member  241  extends through the neck  228 , along side the coupling passageway  232 , and partially into the coupling head  230 . The securing member  241  is structured (such as through sizing or material selection) to retain the flexible nature of the neck  228  and permit transition between the first decoupled position ( FIG. 6 ) and the second coupled position ( FIG. 7 ), while at the same time providing additional strength to the neck  228  and passageway  232 .  
         [0030]     It will be recognized by those skilled in the art that the securing member  241  may take many forms. For example, the outer wire  238  could be extended into the neck  228  and/or coupling head  230  instead of the mandrel  240 . Further, rather than unitarily forming the securing member  241  as an extension of the main body  222 , the securing member  241  may be separately formed and attached to either the mandrel  240  and/or the outer wire  238 , or not attached at all. When separately formed, the securing member  241  can be made of various metals, alloys, plastics or combinations thereof (e.g., a plastic could be selected that is stiffer or stronger than that used for the coupling tip). As previously discussed, the main body  222  can take many forms, and likewise the securing member  241  may also take many forms and shapes.  
         [0031]     The coupling wire guide of the present invention provides secure coupling to a previously introduced wire guide with easy and reliable translation along the previously introduced wire guide. At the same time, the wire guide has an uncoupled position where the coupling tip maintains an aligned and generally low profile to improve maneuverability of the coupling wire guide when decoupled. In the coupled mode, the tip portion itself bends to permit the coupling wire guide and previously introduced wire guide to be aligned generally and parallel for smooth translation of the two guides relative to one another. In this manner, the previously introduced wire guide does not need to bend or deform in order to couple and translate the two wire guides relative to one another.  
         [0032]     The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.