Abstract:
Devices and methods for coupling guidewire system components are disclosed. A guidewire system includes a first wire having a first end and a second wire having a second end which may be selectively coupled to the first end of the first wire. Such guidewire systems are useful as guidewire extension systems.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates generally to guidewires. More particularly, the invention relates to guidewire extension systems.  
         BACKGROUND OF THE INVENTION  
         [0002]    Guidewires are currently utilized in a wide variety of medical procedures. In some situations, it would be desirable to provide a guidewire extension system to effectively extend the overall length of the guidewire.  
           [0003]    In at least some cases, it would be desirable to provide an alternative extension system including an extension wire to be attached to the guidewire in a novel manner.  
         SUMMARY OF THE INVENTION  
         [0004]    The invention is directed to guidewires, and in at least some embodiments, to guidewires for use in percutaneous surgical procedures. More particularly, the invention relates to guidewire extension systems. A guidewire system in accordance with the invention includes a first wire having a first end and a second wire having a second end which can be selectively coupled to the first end of the first wire. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a partial plan view of a guidewire system in accordance with an exemplary embodiment of the invention;  
         [0006]    [0006]FIG. 2 is an enlarged plan view having a first end portion of a first wire and a second end portion of a second wire of the guidewire extension system of FIG. 1;  
         [0007]    [0007]FIG. 3 is an additional plan view of the first end portion of the first wire and the second end portion of the second wire of FIG. 2 showing the struts of the second wire being deflected inward;  
         [0008]    [0008]FIG. 4 is an additional plan view of the first end portion of the first wire and the second end portion of the second wire of FIGS. 2 and 3, the first end portion of the first wire is coupled to the second end portion of the second wire;  
         [0009]    [0009]FIG. 5 is a partial perspective view of another exemplary embodiment of a guidewire extension system showing a first end portion of a first wire and a second end portion of a second wire;  
         [0010]    [0010]FIG. 6 is a perspective view of the guidewire extension system of FIG. 6, showing the first and second wire coupled together;  
         [0011]    [0011]FIG. 7 is a plan view illustrating a first end portion of a first wire and a second end portion of a second wire which can form a portion of a guidewire extension system in accordance with another exemplary embodiment of the invention;  
         [0012]    [0012]FIG. 8 is an additional plan view of the first end portion of the first wire and the second end portion of the second wire of FIG. 7 in a partially coupled position;  
         [0013]    [0013]FIG. 9 is an additional plan view of the first end portion of the first wire and the second end portion of the second wire of FIGS. 7 and 8, in which the first end portion of the first wire is coupled to the second end portion of the second wire;  
         [0014]    [0014]FIG. 10 is a partial perspective view of another exemplary embodiment of a guidewire extension system showing a first end portion of a first wire and a second end portion of a second wire;  
         [0015]    [0015]FIG. 11 is a plan view of a portion of the guidewire system of FIG. 10;  
         [0016]    [0016]FIG. 12 is an additional plan view of the guidewire system of FIGS. 10 and 11 showing the wires coupled together;  
         [0017]    [0017]FIG. 13 is a partial cross sectional view of a portion of a guidewire system having a first wire and a second wire in accordance with yet another embodiment of the invention;  
         [0018]    [0018]FIG. 14 is an additional partial cross sectional view of the guidewire system of FIG. 13, in which the first wire and the second wire are coupled together;  
         [0019]    [0019]FIG. 15 is a partial cross sectional view of a portion of a guidewire system having a first wire and a second wire in accordance with yet another embodiment of the invention;  
         [0020]    [0020]FIG. 16 is an additional partial cross sectional view of the guidewire system of FIG. 15, in which the first wire and the second wire are coupled together;  
         [0021]    [0021]FIG. 17 is a partial cross sectional view of a portion of a guidewire system having a first wire and a second wire in accordance with yet another embodiment of the invention;  
         [0022]    [0022]FIG. 18 is an additional view of the guidewire system of FIG. 17, in which the first wire and the second wire are coupled together;  
         [0023]    [0023]FIG. 19 is a partial cross sectional view of a portion of a guidewire system having a first wire and a second wire in accordance with yet another embodiment of the invention;  
         [0024]    [0024]FIG. 20 is an additional view of the guidewire system of FIG. 19, in which the first wire and the second wire are coupled together;  
         [0025]    [0025]FIG. 21 is a partial cross sectional view of a portion of a guidewire system having a first wire and a second wire in accordance with yet another exemplary embodiment of the invention;  
         [0026]    [0026]FIG. 22 is an additional view of the guidewire system of FIG. 21, in which the first wire and the second wire are coupled together;  
         [0027]    [0027]FIG. 23 is a partial cross sectional view of a portion of a guidewire system having a first wire and a second wire in accordance with yet another exemplary embodiment of the invention;  
         [0028]    [0028]FIG. 24 is an additional view of the guidewire system of FIG. 23, in which the first wire and the second wire are coupled together;  
         [0029]    [0029]FIG. 25 is a partial cross sectional view of a portion of a guidewire extension system having a first wire and a second wire in accordance with yet another exemplary embodiment of the invention;  
         [0030]    [0030]FIG. 26 is a partial cross sectional view of the guidewire system of FIG. 25, wherein the first wire and the second wire are coupled together;  
         [0031]    [0031]FIG. 27 is a partial cross sectional view of a portion of a guidewire extension system having a first wire and a second wire in accordance with yet another exemplary embodiment of the invention;  
         [0032]    [0032]FIG. 28 is a partial cross sectional view of the guidewire system of FIG. 27, wherein the first wire and the second wire are coupled together;  
         [0033]    [0033]FIG. 29 is a partial cross sectional view of a portion of a guidewire extension system having a first wire and a second wire in accordance with yet another exemplary embodiment of the invention;  
         [0034]    [0034]FIG. 30 is a partial cross sectional view of the guidewire system of FIG. 29, wherein the first wire and the second wire are coupled together;  
         [0035]    [0035]FIG. 31 is a partial cross sectional view of a portion of a guidewire extension system having a first wire and a second wire in accordance with yet another exemplary embodiment of the invention;  
         [0036]    [0036]FIG. 32 is a partial cross sectional view of the guidewire system of FIG. 31, wherein the first wire and the second wire are coupled together;  
         [0037]    [0037]FIG. 33 is a partial cross sectional view of a portion of a guidewire system having a first wire coupled to a second wire in accordance with yet another embodiment of the invention;  
         [0038]    [0038]FIG. 34 is an additional view of the guidewire system of FIG. 33, in which the first wire and the second wire are separated;  
         [0039]    [0039]FIG. 35 is a partial cross sectional view of an exemplary embodiment of another invention disclosed herein relating to structure and methods of attaching a coil onto a tube or guidewire, showing an assembly including two different coils;  
         [0040]    [0040]FIG. 36 is a partial cross sectional view of an assembly in accordance with the embodiment of FIG. 35, showing the coils disposed about a cylindrical member; and  
         [0041]    [0041]FIG. 37 is an additional view of the assembly of FIG. 30, showing the second coil tightened around the cylindrical member. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0042]    The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. In some cases, the drawings may be highly diagrammatic in nature. Examples of constructions, materials, dimensions, and manufacturing processes are provided for various elements. Those skilled in the art will recognize that many of the examples provided have suitable alternatives which may be utilized.  
         [0043]    [0043]FIG. 1 is a plan view of a guidewire extension system  100  in accordance with an exemplary embodiment of the invention. Guidewire system  100  includes a first wire  102  and a second wire  104 . First wire  102  comprises a body member  106  having a first end  120  and a second end  119 . First wire  102  also includes a distal tip  128  fixed to body member  106  proximate second end  119 .  
         [0044]    A distal sheath  130  is disposed about body member  106  proximate second end  119 . Preferably, the distal sheath  130  is generally fixed in position relative to the body member. In a preferred embodiment, one end portion  114  of distal sheath  130  is fixed to distal tip  128  and another end portion  116  of distal sheath  130  is fixed to body member  106  of first wire  102 . Also in a preferred embodiment, distal sheath  130  has a high level of longitudinal pushability and a high level of lateral flexibility. Distal sheath  130  preferably comprises a coil  110  having a plurality of turns  112 . Body member  106  of first wire  102  preferably has a generally cylindrical shape. Second wire  104  includes a body member  108  having a first end  125  and a second end  126 . Second end  126  of second wire  104  is adapted and configured to be coupled to first end  120  of first wire  102 .  
         [0045]    [0045]FIG. 2 is a plan view illustrating first end portion  122  of first wire  102  and a second end portion  121  of second wire  104  in a non-coupled position. In FIG. 2, it can be appreciated that second wire  104  includes a plurality of struts  134  that extend beyond second end  126  of body member  108  of second wire  104 . Each strut  134  includes a proximal portion  136  which is fixed to body member  108  proximate second end  126  and a generally enlarged portion  140 .  
         [0046]    First wire  102  includes a plurality of struts  144  which extend beyond first end  120  of body member  106  of first wire  102 . Each strut  144  includes a proximal portion  137  which is fixed to body member  106  proximate first end  120  and a generally enlarged portion  141 . Proximal portions  137  define a plurality of apertures  150 . In a preferred embodiment, apertures  150  are sized to receive generally enlarged portions  140  of struts  134 .  
         [0047]    [0047]FIG. 3 is a plan view of the embodiment of FIG. 2 showing first end portion  122  of first wire  102  and second end portion  121  of second wire  104  and wherein struts  134  of second wire  104  have been deflected inward. In one method in accordance with the invention, struts  134  are deflected inward and second wire  104  is advanced toward first wire  102  until generally enlarged portions  140  of struts  134  are proximate apertures  150  defined by struts  144 . Struts  134  of second wire  104  are then released so that they are free to return to an undeflected state. In this method, first wire  102  and second wire  104  may become fixed to each other by an intermeshing of struts  144  of first wire  102  and struts  134  of second wire  104 .  
         [0048]    [0048]FIG. 4 is a plan view of first end portion  122  of first wire  102  and second end  121  of second wire  104  of FIGS. 2 and 3. First wire  102  and second wire  104  are fixed to each other by an intermeshing of struts  144  of first wire  102  and struts  134  of second wire  104 . Generally enlarged portions  140  of struts  134  are disposed within apertures  150  defined by struts  144 .  
         [0049]    [0049]FIG. 5 is a partial perspective view of another exemplary embodiment of a guidewire extension system  200 . A first end portion  222  of a first wire  202  includes a body member  206  and a second end portion  221  of a second wire  204  includes a body member  208 . The first end portion  222  includes a generally hollow tubular portion  230  defining a cavity  232  therein. The tubular portion  230  has a tapered end  234  defining an opening  236  in fluid communication with the cavity  232 . The tubular portion  230  also defines an opening  237  in fluid communication with the cavity  232 . Preferably, the opening  237  includes a wide portion  238  and a narrow portion  240  and is generally T-shaped. The narrow portion  240  is preferably in fluid communication with opening  236 .  
         [0050]    The second end portion  221 , includes a recessed portion  242  and a wide portion  244  disposed on the end of the recessed portion  242 . Preferably, the recessed portion  242  is generally annular in shape. The recessed portion  242  and the wide portion  244  together form structure  246  that is adapted and configured to mate with the tubular portion  230  to couple the first end portion  222  to the second end portion  221 . The structure can be inserted into the cavity  232  through the opening  237 . The wide portion  244  fits in to the wide portion  238 , and the recessed portion  242  fits into the narrow portion  240 .  
         [0051]    Referring now to FIG. 6, once the structure  246  is within the cavity  232 , the wide portion  244  is pulled toward the tapered end  234 . The first and second wires are thereby selectively coupled together.  
         [0052]    [0052]FIG. 7 is an enlarged partial plan view of another embodiment. This embodiment includes a first end portion  322  of a first wire  302  including a body member  306 , and a second end portion  321  of a second wire  304  including a body member  308 . The second wire  304  includes a plurality of struts  334  which extend beyond a second end  326  of body member  308  of second wire  304 . Each strut  334  includes a proximal portion  336  which is fixed to body member  308  proximate second end  326  and a generally enlarged portion  340 .  
         [0053]    First wire  302  includes an outer surface  352  defining a plurality of apertures  350 . Outer surface  352  preferably has a generally cylindrical shape, although other shapes are contemplated. Preferably, each aperture  350  is in fluid communication with a cavity  354  defined by body member  306  of first wire  302  but this is not necessary. Outer surface  252  of body member  306  of first wire  302  also defines a plurality of channels  356 . Each channel  356  is preferably in fluid communication with a cavity  354 . Each aperture  350  and its associated channel  356  form a generally keyhole shaped recess. In FIG. 7 it may be appreciated that body member  306  includes a tapered portion  358  proximate first end portion  322 . Tapered portion  358  preferably has an outer diameter that is less than an outer diameter of struts  334 . In some embodiments, at least a portion of the tapered portion  358  preferably has an outer diameter that is less than an inside diameter of a portion of struts  334 .  
         [0054]    [0054]FIG. 8 is a plan view of the embodiment of FIG. 9, wherein the first end portion  322  of first wire  302  and second end portion  321  of second wire  304  have been urged toward one another and are partially coupled. Struts  334  of second wire  304  deflect outwardly as they ride upon an outer surface of tapered portion  358 .  
         [0055]    [0055]FIG. 9 is an additional plan view of FIGS. 7 and 8 wherein the first end portion  322  of first wire  302  and second end portion  321  of second wire  304  have been further urged toward one another and are coupled together. The generally enlarged portion  340  of each strut  334  of second wire  304  is disposed within a cavity  354  defined by body member  306  of first wire  302 .  
         [0056]    [0056]FIG. 10 is a perspective view of yet another exemplary embodiment of a guidewire system  400 . First end portion  422  of a first wire  402  and a second end portion  421  of a first wire  404  are shown. In FIG. 10, it can be appreciated that a body member  406  of first wire  402  defines a recess  460 , a tapered end portion  458  and a plurality of channels  456 . One channel  456  is visible in FIG. 10, and another channel (not visible in FIG. 10) is disposed generally opposite of the visible channel  456 . The recess  460  has a generally annular shape.  
         [0057]    The wire  404  includes struts  434  which extend beyond an end  426  of a body member  408  of wire  404 . Each strut  434  includes a proximal portion  436  which is fixed to body member  408  proximate end  426  and a generally enlarged portion  440 . Proximal portion  436  of struts  434  define a plurality of apertures  450 .  
         [0058]    [0058]FIG. 11 is a plan view of a portion of the guidewire system  400  shown in FIG. 10. It can be appreciated that body member  406  of first wire  402  includes a tapered portion  458  proximate first end portion  422 .  
         [0059]    [0059]FIG. 12 is a plan view of first end portion  422  of first wire  402  and a second end portion  421  of second wire  404  of FIG. 11 wherein the wires are coupled together. First end portion  422  of first wire  402  and second end portion  421  of wire  404  have been urged toward one another. A generally enlarged portion  440  of each strut  434  of wire  404  is disposed within the annular recess  460  defined by a body member  406  of first wire  402 . Additionally, each proximal portion  436  of each strut  434  is disposed within one of the channels  456 .  
         [0060]    [0060]FIG. 13 is a partial cross sectional view of a portion of a guidewire system  500  in accordance with yet another embodiment of the invention. Guidewire system  500  includes a first wire  502  including a first body member  504  having a first end portion  506  and a second wire  508  including a second body member  510  having a second end portion  512 . A first tubular member  514  is fixed to first body member  504  of first wire  502  proximate first end portion  506  thereof. First tubular member  514  includes a wall  516  defining a lumen  518  and a crimped portion  520  in which an inner diameter of wall  516  is generally reduced. A second tubular member  522  is fixed to second body member  510  of second wire  508  proximate second end portion  512  thereof. Second tubular member  522  defines a plurality of slots  524 . Slots  524  define a plurality of fingers  526  of second tubular member  522 . It can be appreciated that fingers  526  of second tubular member  522  are generally flared outward.  
         [0061]    [0061]FIG. 14 is an additional view of guidewire system  500  of FIG. 13, wherein the second tubular member  522  has been inserted into first tubular member  514 . It can be appreciated that fingers  526  of second tubular member  522  are adapted to seat against crimped portion  520  of first tubular member  514  to limit axial movement of second wire  508  relative to first wire  502 . Embodiments of first tubular member  514  are possible in which a crimped portion  520  comprises a plurality of depressions. Embodiments of second tubular member  522  are possible in which slots  524  and fingers  526  have a generally helical shape.  
         [0062]    [0062]FIG. 15 is a partial cross sectional view of a portion of a guidewire system  501  in accordance with yet another embodiment of the invention. Guidewire system  501  includes a first wire  503  including a first body member  505  having a first end portion  507  and a second wire  508 . The second wire  508  is substantially the same as second wire  508  shown in FIGS. 13 and 14, with like reference numerals being used to identify like structures.  
         [0063]    The first wire  503  includes a first tubular member  515  and a second tubular member  517  coupled to the body member  505  proximate the end portion  507  of first wire  503 . The second tubular member  517  includes a narrow portion  519  that is adapted to fit within a portion of first tubular member  515  and forms an annulus within first tubular member. Narrow portion  519  includes an end surface  521 .  
         [0064]    [0064]FIG. 16 is an additional view of the guidewire system  501  of FIG. 15, wherein the tubular member  522  has been inserted into the tubular members  515  and  517  to couple the two wires  501  and  508  together. It can be appreciated that fingers  526  of the second wire  508  are adapted to seat against the end surface  521  of the first wire  508  to limit the axial movement of the wires  503  and  508  relative to one another.  
         [0065]    [0065]FIG. 17 is a partial cross sectional view of a portion of a guidewire system  530  in accordance with yet another embodiment of the invention. Guidewire system  530  includes a first wire  532  including a first body member  534  having a first end  536 . First body member  534  of first wire  532  includes a first surface  544  and a second surface  546  that define an annular cavity  548 . Guidewire system  530  also includes a second wire  538  including a second body member  540  having a second end  542 . Second body member  540  of second wire  538  includes a wall  550  defining a lumen  552  and a plurality of flaps  554  extending into lumen  552 .  
         [0066]    [0066]FIG. 18 is an additional view of the guidewire system  530  of FIG. 17 wherein the first end  536  of first wire  532  has been inserted into the lumen  552  of the second wire  538 . The flaps  554  of second wire  538  are seated against second surface  546  of first wire  532 . Flaps  554  and second surface  546  preferably limit axial movement of second wire  538  relative to first wire  532 .  
         [0067]    [0067]FIG. 19 is a partial cross sectional view of a portion of a guidewire system  560  in accordance with yet another embodiment of the invention. Guidewire system  560  includes a first wire  562  including a first body member  564  having a first end  566 . First body member  564  of first wire  562  includes a first surface  574  and a second surface  576  that define an annular cavity  578 . Guidewire system  560  also includes a second wire  568  including a second body member  570  having a second end  572 . Second body member  570  of second wire  568  includes a wall  580  defining a lumen  584  and a plurality of arms  582  extending into lumen  584 .  
         [0068]    [0068]FIG. 20 is an additional view of the guidewire system  560  of FIG. 19 wherein first end  566  of first wire  562  has been inserted into lumen  584  of second wire  568 . The arms  582  of second wire  568  are seated against second surface  576  of first wire  562 . Arms  582  and second surface  576  preferably limit axial movement of second wire  568  relative to first wire  562 .  
         [0069]    [0069]FIG. 21 is a partial cross sectional view of a portion of a guidewire system  600  in accordance with yet another embodiment of the invention. Guidewire system  600  comprises a first wire  602  including a first body member  604  comprising a wall  606  defining a lumen  608 , and an annulus  610  disposed within lumen  608  proximate a first end  612  of first body member  604 . Annulus  610  of first wire  602  defines an aperture  622  and a first surface  624 . Guidewire system  600  also includes a second wire  614 . Second wire  614  includes a second body member  616  having a second end  618 . A coil  620  is disposed about second body member  616  of second wire  614  proximate second end  618  of second wire  614 . Preferably, the coil  620  is maintained about second body member  616  by widening portion  617  proximate second end  618  of second wire  614 . It will be understood, however, that the coil  620  can be maintained on the second body member in a broad variety of other ways.  
         [0070]    [0070]FIG. 22 is an additional view of the guidewire system  600  of FIG. 21, wherein the second end  618  of second wire  614  has been inserted into aperture  622  of annulus  610  of first wire  602 . It can be appreciated that coil  620  of second wire  614  may seat against first surface  624  of annulus  610  to limit axial movement of second wire  614  relative to first wire  602 .  
         [0071]    [0071]FIG. 23 is a partial cross sectional view of a portion of a guidewire system  601  in accordance with yet another embodiment of the invention. Guidewire system  601  comprises a first wire  602  that is substantially the same as the first wire  602  shown in FIGS. 21 and 22, and therefore includes a first body member  604  comprising a wall  606  defining a lumen  608 , and an annulus  610  disposed within lumen  608  proximate a first end  612  of first body member  604 . Annulus  610  of first wire  602  defines an aperture  622  and a first surface  624 . Guidewire system  601  also includes a second wire  615 . Second wire  615  includes a second body member  619  having a second end  621 . A coil  623  is disposed about second body member  619  of second wire  615  proximate second end  621  of second wire  615 . Preferably the coil  623  is maintained about second body member  619  of second wire  615  by attachment of at least a portion of the coil  623  to the body member.  
         [0072]    [0072]FIG. 24 is an additional view of the guidewire system  601  of FIG. 23. In the embodiment of FIG. 24, second end  621  of second wire  615  has been inserted into aperture  622  of annulus  610  of first wire  602 . It can be appreciated that coil  623  of second wire  615  can seat against first surface  624  of annulus  610  to limit axial movement of second wire  615  relative to first wire  602 .  
         [0073]    [0073]FIG. 25 is a partial cross sectional view of a portion of a guidewire system  631  in accordance with yet another embodiment of the invention. Guidewire system  631  comprises a first wire  503  that is substantially the same as the first wire  503  shown in FIGS. 15 and 16, and a second wire  614  that is substantially the same as the second wire  614  shown in FIGS. 21 and 22, with like reference numerals being used to identify like structure.  
         [0074]    [0074]FIG. 26 is an additional view of the guidewire system  631  of FIG. 25, wherein the second end  618  of second wire  614  has been inserted into tubular members  515  and  517  to couple the wires  503  and  614  together. It can be appreciated that the coil  620  is adapted to seat against the end surface  521  of the first wire  503  to limit the axial movement of second wire  614  relative to first wire  503 .  
         [0075]    [0075]FIG. 27 is a partial cross sectional view of a portion of a guidewire system  651  in accordance with yet another embodiment of the invention. Guidewire system  651  comprises a first wire  503  that is substantially the same as the first wire  503  shown in FIGS. 15 and 16, and a second wire  615  that is substantially the same as the second wire  615  shown in FIGS. 23 and 24, with like reference numerals being used to identify like structure.  
         [0076]    [0076]FIG. 28 is an additional view of the guidewire system  651  of FIG. 27, wherein the second end  621  of second wire  615  has been inserted into tubular members  515  and  517  to couple the wires together. It can be appreciated that the coil  623  is adapted to seat against the end surface  521  of the first wire  503  to limit the axial movement of second wire  615  relative to first wire  503 .  
         [0077]    [0077]FIG. 29 is a partial cross sectional view of a portion of a guidewire system  630  in accordance with yet another embodiment of the invention. Guidewire system  630  comprises a first wire  632  including a first body member  634  comprising a wall  636  defining a lumen  638 , and a female thread  640  disposed within lumen  638  proximate a first end  646  of first body member  634 . Female thread  640  of first wire  632  defines an aperture  642  and a first surface  644 . Guidewire system  630  also includes a second wire  648 . Second wire  648  includes a second body member  650  having a second end  652 . A coil  654  is disposed about second body member  650  of second wire  648  proximate second end  652 . Preferably, at least a portion of the coil  654  is rigidly attached to the body member  650 .  
         [0078]    [0078]FIG. 30 is an additional view of the guidewire system  630  of FIG. 29, wherein the coil  654  of second wire  648  has been threaded through female thread  640  of first wire  632 . It can be appreciated that coil  654  of second wire  648  can set against first surface  644  of female thread  640  to limit axial movement of second wire  648  relative to first wire  632 .  
         [0079]    [0079]FIG. 31 is a partial cross sectional view of a portion of a guidewire system  660  in accordance with yet another embodiment of the invention. Guidewire system  660  comprises a first wire  662  and a second wire  674 . First wire  662  includes a first body member  664  comprising a wall  668  defining a lumen  672 , and a female thread  670  disposed within lumen  672  proximate a first end  686  of first body member  664 . Second wire  674  includes a second body member  676  having a second end  678 . A male thread  680  is disposed about second body member  676  of second wire  674  proximate second end  678  of second wire  674 . Male thread  680  includes a first portion  682  which is adapted to threadingly engage female thread  670 . Male thread  680  also includes a second portion  684  which is different from first portion  682  of male thread  680  (e.g., different pitch or different thread size). In a preferred embodiment of the invention, second portion  684  of male thread  680  is adapted to deform when male thread  680  is threaded into female thread  670 .  
         [0080]    [0080]FIG. 32 is an additional view of guidewire system  660  of FIG. 21, wherein the male thread  680  has been threaded into female thread  670 . Also it can be appreciated that second portion  684  of male thread  680  has been deformed. The deformation of second portion  684  of male thread  680  preferably acts to reduce or prevent rotation of female thread  670  relative to male thread  680 .  
         [0081]    [0081]FIG. 33 is a partial cross sectional view of a portion of a guidewire system  730  in accordance with yet another embodiment of the invention. Guidewire system  730  includes a first wire  732  including a first body member  734  having a first end  736 . First body member  734  of first wire  732  includes a zig-zag shaped tip portion  744 . First wire  732  also includes a first tubular member  746  which is disposed about zig-zag shaped tip portion  744  and fixed to first body member  734 . Preferably, zigzag shaped tip portion  744  is a bias-able, yet resilient material.  
         [0082]    Guidewire system  730  also includes a second wire  738  including a second body member  740  having a second end  742  and a second tubular member  754  fixed to second body member  740  proximate second end  742 . Second tubular member  754  of second wire  738  includes a wall  750  defining a lumen  752 . The zigzag shaped tip portion  744  of first wire  732  is disposed within lumen  752  of second tubular member  754 . The zig-zag shaped tip portion  744  may be inserted into lumen  752  of second tubular member  754  by straightening it under spring tension and advancing it.  
         [0083]    [0083]FIG. 34 is an additional view of the guidewire system  730  of FIG. 33, wherein the first wire  732  and second wire  738  have been separated from one another. In FIG. 34 it can be appreciated that once zig-zag shaped tip portion  744  is removed from lumen  752  of second tubular member  754 , it is free to return to an uncompressed position.  
         [0084]    [0084]FIG. 35 is a partial cross sectional view of an assembly  760  in accordance with another different aspect of an invention disclosed herein. This different aspect relates to structure and method of connecting a coil onto a tube or guidewire. Assembly  760  includes a first coil  762  and a second coil  764 . First coil  762  includes a plurality of turns  766  which are spaced apart to accommodate a plurality of turns  768  of second coil  764 . Second coil  764  is threaded or turned into first coil  762  so at least some of the turns  768  of second coil  764  are disposed between adjacent turns  766  of first coil  762 .  
         [0085]    [0085]FIG. 36 is a partial cross sectional view of an additional assembly  780  including first coil  762  and second coil  764  of FIG. 35. A member  770  having a generally cylindrical outer surface  774  is disposed within a lumen  772  defined by first coil  762  and second coil  764 . Member  770  may be a tube, a core wire, or the like. For example, the member  770  may be a distal end of a guidewire.  
         [0086]    In a preferred embodiment, second coil  764  comprises a shape memory material. Examples of shape memory materials which may be suitable in some applications include shape memory alloys and shape memory thermoplastics. Examples of shape memory alloys which may be suitable in some applications include Nitinol. The word Nitinol was coined by a group of researchers at the United States Naval Ordinance Laboratory (NOL) who were the first to observe the shape memory behavior of this material. The word Nitinol is an acronym including the chemical symbol for nickel (Ni), the chemical symbol for titanium (Ti), and the acronym for identifying the Naval Ordinance Laboratory (NOL).  
         [0087]    [0087]FIG. 37 is an additional view of assembly  780  of FIG. 36. Second coil  764  has been caused to shrink, for example, by a change in temperature. Second coil  764  preferably grasps outer surface  774  of member  770  when it is in the shrunken state shown in FIG. 37. Second coil  764  may be utilized to fix first coil  762  to member  770 . For example, axial movement of second coil  764  relative to member  770  is precluded since at least some turns  768  of second coil  764  are disposed between at least some turns  766  of first coil  762 .  
         [0088]    In some embodiments, a guidewire can include the method and structure for connecting a coil onto a tube or guidewire, for example, as depicted in FIGS.  35 - 37 , along with an embodiment of an extension system, for example, as depicted in FIGS. 134. Other embodiments can include only an extension system. In yet another embodiment, a guidewire can include only a method and structure for connecting a coil onto a tube or guidewire.  
         [0089]    In some embodiments, guidewires as disclosed herein in accordance with the invention can be used in conjunction with an intravascular catheter that enables a physician to remotely perform a therapeutic medical procedure. Some examples of therapeutic purposes for catheters include percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasty (PTCA), the treatment of intracranial aneurysms in the brain and the like.  
         [0090]    Guidewires are often utilized to assist in advancing the intravascular catheter through the vasculature of a patient. A guidewire may be inserted into the vascular system of the patient at an easily accessible location and urged forward through the vasculature until the tip of the guidewire is proximate the target site. A proximal end of the guidewire may then be inserted into a guidewire lumen of a catheter. The tip of the catheter may be advanced along the length of the guidewire until it reaches the target site.  
         [0091]    It is sometimes necessary to remove one intravascular catheter and replace it with another. When this is the case, it is usually preferred that the first catheter be removed in a manner which enables the guidewire to remain in place in the blood vessel so that the second catheter can be inserted into the blood vessel over the guidewire. In order to maintain the position of the guidewire while withdrawing the first catheter, the guidewire typically must be gripped at its proximal end to prevent it from being pulled out of the blood vessel together with the catheter. The extension system of at least some embodiments of the invention allow an extension wire to be attached to a proximal end of the guidewire which is already in place in the body. This effectively extends the overall length of the guidewire to that needed for catheter exchange. Additionally, it is preferred that in most embodiments, the connection between the guidewire and the extension wire preferably presents low resistance to catheters that are passed over the connection.  
         [0092]    Having thus described the preferred embodiments of the present invention, those of skill in the art will readily appreciate that yet other embodiments may be made and used within the scope of the claims hereto attached. Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the invention. The invention&#39;s scope is, of course, defined in the language in which the appended claims are expressed.