Abstract:
A method of bonding tubular members comprising the steps of, providing a first generally tubular member having a bonding portion disposed proximate a bonding end thereof, an ancillary end, and a lumen extending therethrough, the first tubular member including a support member encased in a substrate material, the support member having a plurality of filaments providing a second generally tubular member having a bonding portion disposed proximate a bonding end thereof, an ancillary end, and a lumen extending therethrough, stripping a portion of the substrate material of the first tubular member from the filaments of the support member of the first tubular member proximate the bonding portion thereof to create a plurality of exposed filaments, inserting the exposed filaments into the lumen of the second tubular member, positioning the bonding portion of the first tubular member proximate the bonding portion of the second tubular member, and heating the bonding portion of the first tubular member and the bonding portion of the second tubular member to form a bond therebetween.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to catheters for performing medical procedures. More particularly, the present invention relates to methods of fabricating catheters having one or more guidewire ports and two or more tubular members. 
     BACKGROUND OF THE INVENTION 
     Intravascular catheters are currently utilized in a wide variety of minimally-invasive medical procedures. Generally, an intravascular catheter enables a physician to remotely perform a medical procedure by inserting the catheter into the vascular system of the patient at an easily accessible location and navigating the tip of the catheter to the desired target site. By this method, virtually any target site in the patient&#39;s vascular system may be remotely accessed, including the coronary, cerebral, and peripheral vasculature. 
     Typically, the catheter enters the patient&#39;s vasculature at a convenient location such as a blood vessel in the neck or near the groin. Once the distal portion of the catheter has entered the patient&#39;s vascular system the physician may urge the distal tip forward by applying longitudinal forces to the proximal portion of the catheter. For the catheter to effectively communicate these longitudinal forces it is desirable that the catheter have a high level of pushability and kink resistance particularly near the proximal end. 
     Frequently the path taken by a catheter through the vascular system is tortuous, requiring the catheter to change direction frequently. In some cases, it may even be necessary for the catheter to double back on itself. In order for the catheter to conform to a patient&#39;s tortuous vascular system, it is desirable that intravascular catheters be very flexible, particularly near the distal end. 
     While advancing the catheter through the tortuous path of the patients vasculature, physicians often apply torsional forces to the proximal portion of the catheter to aid in steering the catheter. To facilitate the steering process, the distal portion of the catheter may include a plurality of bends or curves. Torsional forces applied on the proximal end must translate to the distal end to aid in steering. It is therefore desirable that the proximal portion of an intravascular catheter have a relatively high level of torquability to facilitate steering. 
     After the intravascular catheter has been navigated through the patient&#39;s vascular system so that its distal end is adjacent the target site, the catheter may be used for various diagnostic and/or therapeutic purposes. One example of a diagnostic use for an intravascular catheter is the delivery of radiopaque contrast solution to enhance fluoroscopic visualization. In this application, the intravascular catheter provides a fluid path leading from a location outside the body to a desired location inside the body of a patient. In order to maintain a fluid path, it is desirable that intravascular catheters be sufficiently resistant to kinking. In addition, because such fluids are delivered under pressure, it is also desirable that intravascular catheters be sufficiently resistant to bursting or leaking. 
     Examples of therapeutic purposes for intravascular catheters include percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA). These angioplasty techniques typically involve the use of a guide catheter and a balloon catheter. During these procedures, the distal end of the guide catheter is typically inserted into the femoral artery located near the groin of the patient. The guide catheter is urged through the vasculature of the patient until its distal end is proximate the restriction. In many cases, the distal end of the guide catheter is positioned in the ostium of the coronary artery. The balloon catheter may then be fed through a lumen in the guide catheter such that the balloon is positioned proximate a restriction in a diseased vessel. The balloon is then inflated and the restriction in the vessel is opened. In this application, it is desirable that the guide catheter provide a low friction path for the balloon catheter. The balloon is inflated by urging a liquid though the elongate shaft of the balloon catheter and into the balloon. In this application, the balloon catheter must provide an unobstructed path for the inflation fluid. It is also desirable that the catheter be substantially free of leaks. 
     As described at length above, it is desirable to combine a number of performance features in an intravascular catheter. It is desirable that the catheter have a relatively high level of pushability and torqueability, particularly near its proximal end. It is also desirable that a catheter be relatively flexible, particularly near it&#39;s distal end. The need for this combination of performance features is often addressed by building a catheter which has two or more discrete tubular members having different performance characteristics. For example, a relatively flexible distal section may be spliced to a relatively rigid proximal section. When a catheter is formed from two or more discrete tubular members, it is often necessary to form a bond between the distal end of one tubular member and the proximal end of another tubular member. 
     Intravascular catheters are often used in conjunction with a guidewire. When this is the case, the guidewire may be advanced through the patient&#39;s vasculature until its distal tip has reached a desired target location. Once the distal portion of the guidewire is proximate the desired location, the catheter may be threaded onto the guidewire and urged distally until the distal end of the catheter is proximate the target location. 
     Intravascular catheters adapted for use with a guidewire typically fall into one of two categories: the over-the-wire category or the single operator exchange (SOE) category. An over-the wire type of catheter includes a guidewire lumen extending from the distal tip of the catheter to the proximal end of the catheter. Whereas, a single operator exchange catheter typically includes a relatively short guidewire lumen proximate the distal end of the catheter. 
     Single operator exchange catheters were developed in response to difficulties encountered when exchanging over-the-wire catheters. Generally, it is desirable to leave the guidewire in place while a first catheter is withdrawn from the patient and replaced with a second catheter. Maintaining the position of the guidewire tip during the procedure aids the physician in quickly positioning the distal end of the second catheter proximate the target area. 
     In order to keep the guidewire tip near the target area, the guidewire must be held in place throughout the catheter exchange procedure. A portion of the guidewire is typically grasped by the physician in order to withdraw the first catheter while maintaining distal end of the guidewire in the desired position. To properly anchor the guidewire, a portion of the guidewire must be exposed at all times so it is available for the physician to grasp. In the case of an over-the-wire catheter, this requires that the length of the guidewire extending beyond the patient&#39;s body be longer than the catheters. In some cases, length must be added to the guidewire using a guidewire extension. In many cases intravascular catheters are longer than 200 cm. Correspondingly, there may be more than 200 cm of wire extending from the patient. Managing this length of wire during a catheter exchange procedure is awkward, and typically requires two persons. In particular, contamination must be avoided by assuring that the guidewire is not dropped from the sterile field. 
     An SOE catheter, on the other hand, has a relatively short guidewire wire lumen proximate its distal tip. The length of guidewire extending beyond the body of the patient need only be slightly longer than the guidewire lumen of the catheter. The physician may anchor or hold the guidewire as the first catheter is removed from the body with the exchange occurring over the shorter guidewire lumen. The guidewire lumen of an SOE catheter typically includes a distal guidewire port disposed at the distal tip of the catheter and a proximal guidewire port disposed proximally of the distal end of the catheter. It is desirable to fabricate an SOE catheter, to include a proximal guidewire port, while maintaining the other desirable performance features described previously. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to catheters for performing medical procedures. More particularly, the present invention relates to methods of fabricating catheters having one or more guidewire ports and two or more tubular members. 
     A catheter assembly in accordance with the present invention includes an elongate shaft having a proximal shaft portion, a middle shaft portion, and a distal shaft portion. The proximal shaft portion, the middle shaft portion, and the distal shaft portion each have a proximal end and a distal end. The distal end of the proximal shaft portion is fixed to the proximal end of the middle shaft portion. Likewise, the distal end of middle shaft portion is fixed to the proximal end of distal shaft portion at a transition region. 
     A presently preferred embodiment of a catheter in accordance with the present invention includes a proximal guidewire port disposed proximate the transition region. The catheter further includes a distal guidewire port disposed proximate the distal end of the elongate shaft. The elongate shaft of the catheter includes a plurality of walls defining a guidewire lumen which is in fluid communication with the proximal guidewire port and the distal guidewire port. 
     The elongate shaft also includes a plurality of walls defining an inflation lumen. The inflation lumen is in fluid communication with a balloon disposed at the distal end of the elongate shaft of the catheter. The inflation lumen is also in fluid communication with a port of a hub assembly disposed about the elongate shaft of the catheter proximate its proximal end. A fluid source may be coupled to the port of the hub assembly. The balloon may be inflated by urging fluid from the fluid source into the balloon via the inflation lumen. 
     The inflation lumen an the guidewire lumen both pass through the transition region of the catheter. In a presently preferred embodiment, the distal end of middle shaft portion is fixed to the proximal end of distal shaft portion proximate the transition region of the catheter. Methods of fabricating a catheter having such a transition region are disclosed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a catheter in accordance with an exemplary embodiment of the present invention; 
     FIG. 2 is a cross sectional view of an exemplary embodiment of a generally tubular shaft; 
     FIG. 3 is a cross sectional view of an assembly including first shaft portion having a first lumen and second shaft portion having a second lumen; 
     FIG. 4 is a cross sectional view of the assembly of FIG. 3 taken along line A—A shown in FIG. 3; 
     FIG. 5 is a cross sectional view of the assembly of FIG. 4 after a portion of the assembly has been fused in accordance with a method of the present invention; 
     FIG. 6 is a cross sectional view of an additional embodiment of a fused region of a transition region of a catheter; 
     FIG. 7 is a cross sectional view of another embodiment of a fused region of a transition region of a catheter; 
     FIG. 8 is a cross sectional view of yet another embodiment of a fused region of a transition region of a catheter; 
     FIG. 9 is a cross sectional view of still another embodiment of a fused region of a transition region of a catheter; 
     FIG. 10 is a cross-sectional view of an assembly in accordance with the present invention; 
     FIG. 11 is a cross-sectional view of an assembly in accordance with the present invention; 
     FIG. 12 is a cross-sectional view of an assembly in accordance with the present invention; 
     FIG. 13 is a cross-sectional view of an assembly in accordance with the present invention; 
     FIG. 14 is a cross-sectional view of an assembly in accordance with the present invention; 
     FIG. 15 is a cross-sectional view of an assembly in accordance with the present invention; 
     FIG. 16 is a cross-sectional view of an assembly including a crimped region and a joint region accordance with the present invention; 
     FIG. 17 is a plan view of first shaft portion including a crimp defining an opening; 
     FIG. 18 is a cross-sectional view of an assembly including a crimped region and a joint region accordance with the present invention; 
     FIG. 19 is a cross-sectional view of an assembly including a crimped region and a joint region accordance with the present invention; 
     FIG. 20 is a cross-sectional view of an assembly including a crimped region and a joint region accordance with the present invention; 
     FIG. 21 is a cross-sectional view of an assembly including a crimped region and a joint region accordance with the present invention; and 
     FIG. 22 is a cross-sectional view of an assembly including a crimped region and a joint region in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered identically. The drawings which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. 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. 
     FIG. 1 is a plan view of a catheter  100  in accordance with an exemplary embodiment of the present invention. Catheter  100  includes an elongate shaft  30  having a distal end  32  and a proximate end  34 . A hub assembly  36  is disposed about elongate shaft  30 , proximate proximal end  34  thereof. Hub assembly  36  includes a plurality of ports  38 . 
     Elongate shaft  30  includes a proximal shaft portion  40 , a middle shaft portion  42 , and a distal shaft portion  44 . Proximal shaft portion  40 , middle shaft portion  42 , and distal shaft portion  44  each have a proximal end and a distal end. As shown in FIG. 1, the distal end of proximal shaft portion  40  is fixed to the proximal end of middle shaft portion  42 . Likewise, the distal end of middle shaft portion  42  is fixed to the proximal end of distal shaft portion  44  proximate a transition region  102 . Those of skill in the art will appreciate that catheter  100  may include more or less than three shaft portions without deviating from the spirit and scope of the present invention. 
     In the embodiment of FIG. 1, catheter  100  includes a proximal guidewire port  46  disposed proximate transition region  102 . Catheter  100  also includes a distal guidewire port  48  disposed proximate distal end  32  of elongate shaft  30 . Elongate shaft  30  includes a plurality of walls defining a guidewire lumen  104  (not shown) which is in fluid communication with proximal guidewire port  46  and distal guidewire port  48 . 
     Elongate shaft  30  also includes a plurality of walls defining an inflation lumen  106  not shown. Inflation lumen  106  is in fluid communication with port  38  of hub  36  and a balloon  50  disposed about elongate shaft  30  proximate distal end  34 . Port  38  of hub  36  is adapted to couple with a fluid source. Balloon  50  may be inflated by urging fluid from the fluid source into balloon  50  via inflation lumen  106 . Catheter  100  of FIG. 1 is a type of catheter which may be generally referred to as a balloon catheter. Those of skill in the art will appreciate that methods and devices in accordance with the present invention may be used to fabricate other types of catheter. 
     Those of skill in the art will appreciate that proximal shaft portion  40 , middle shaft portion  42 , and distal shaft portion  44  may be comprised of many materials without deviating from the spirit and scope of the present invention. An exemplary embodiment of a shaft portion  52  is illustrated in FIG.  2 . 
     FIG. 2 is a cross sectional view of a shaft portion  52 . As shown in FIG. 2, shaft portion  52  is comprised of an inner tube  54  which is overlaid by a support member  112 . An outer layer  108  of a jacket material  110  overlays support member  112 . Jacket material  110  of outer layer  108  is also disposed within a plurality of interstitial spaces defined by support member  112 . In the embodiment of FIG. 2, support member  112  is comprised of a plurality of filaments  114 . In a preferred embodiment, filaments  114  are comprised of stainless steel wire, wound in a braided pattern around inner tube  54 . Those of skill in the art will appreciate that other embodiments of support member  112  are possible without deviating from the spirit and scope of the present invention. For example, support member  112  may be comprised of a plurality of polymer filaments braided or knitted together. By way of a second example, support member  112  may be comprised of polymer filaments wound in a spiral pattern around inner tube  54 . 
     In a presently preferred embodiment, outer layer  108  is comprised of polyether block amide (PEBA). Polyether block amide is commercially available from Atochem Polymers of Birdsboro, Pa. under the trade name PEBAX. Outer layer  108  may be fabricated using an extrusion process. In this process, molten PEBA is extruded onto the combined layers of inner tube  54  and support member  112 . When this process is used, the material of outer layer  108  fills any interstitial spaces in support member  112 . 
     It is to be understood that other manufacturing processes may be used without departing from the spirit and scope of the present invention. Outer layer  108  may also be comprised of other materials without departing from the spirit of scope of this invention. Examples of materials which may be suitable in some applications include: polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyurethane, and polytetrafluoroethylene (PTFE). 
     FIG. 3 is a cross sectional view of an assembly  203  including first shaft portion  116  having a first lumen  118  and second shaft portion  120  having a second lumen  122 . In one method in accordance with the present invention, assembling first shaft portion  116  and second shaft portion  120  as shown in FIG. 3 is one step in a method used to fabricate a transition region  102  of a catheter  100 . A method in accordance with the present invention may also include the step of applying heat to form a fused region bonding first shaft portion  116  and second shaft portion  120 . 
     As shown in FIG. 3, a proximal end  124  of second shaft portion  120  is disposed proximate a distal end  126  of first shaft portion  116  forming a joint  128 . Joint  128  of FIG. 3 may be generally referred to as a butt joint. An inner tubular member or inner  130  is disposed proximate a crimp  132  formed in first shaft portion  116 . As show in FIG. 3, a portion of inner  130  is disposed within second lumen  122  defined by second shaft portion  120 . First lumen  118  of first shaft portion  116  is also visible in FIG.  4 . In a presently preferred embodiment, inner  130  defines a proximal guidewire port  46 , a guidewire lumen  104 , and a distal guidewire port  48  (not shown) of catheter  100 . 
     FIG. 4 is a cross sectional view of assembly  204  taken along line A—A shown in FIG.  3 . The position of inner  130  relative to crimp  132  of first shaft portion  116  is best shown in FIG. 4. A guidewire lumen  104  defined by inner  130  is also shown in FIG.  4 . It may be appreciated that inflation lumen  106  of catheter  100  may include second lumen  122  defined by second shaft portion  120  and a first lumen  118  defined by first shaft portion  116 . 
     As mentioned previously, in one method in accordance with the present invention, assembling first shaft portion  116  and second shaft portion  120  as shown in FIG. 3 may be one step in a method used to fabricate transition region  102  of catheter  100 . A method in accordance with the present invention may also include the step of selectively heating a portion of assembly  204  to create a fused region  134 . In a presently preferred method, the selective heating of a portion of assembly  204  is accomplished by illuminating a portion of assembly  204  with a LASER (light amplification by stimulated emission of radiation) beam. In a presently most preferred method, assembly  204  is rotated while a portion thereof is illuminated with a LASER beam. 
     FIG. 5 is a cross sectional view of assembly  204  of FIG. 4 after a portion of the assembly has been fused in accordance with a method of the present invention. As shown in FIG. 4, a fused region  134  comprising fused material  136  has been formed. A transition region guidewire lumen  105  and a transition region inflation lumen  138  are defined by fused material  136 . In a presently preferred embodiment, transition region inflation lumens  138  is in fluid communication with first lumen  118  of first shaft portion  116  and second lumen  122  of second shaft portion  120 . It may be appreciated that, transition region inflation lumen  138 , first lumen  118 , and second lumen  122  may all form a portion of inflation lumen  106  of catheter  100 . 
     FIG. 6 is a cross sectional view of an additional embodiment of a fused region  234 . In the embodiment of FIG. 6, a core wire  56  is disposed within transition region inflation lumen  138 . In a presently preferred embodiment, core wire  56  passes through transition region  102  and is adapted to provide a desired stiffness to transition region  102  of catheter  100 . Core wire  56  may include one or more tapered regions along its length. The tapered regions of core wire  56  may provide desirable variations in stiffness. 
     FIG. 7 is a cross sectional view of an additional embodiment of a fused region  334 . In the embodiment of FIG. 7, fused material  136  of fused region  334  is disposed about a portion of core wire  56 . In a presently preferred embodiment, fused material  136  of fused region  334  is adapted to retain core wire  56 . Fused material  136  of fused region  334  also defines a plurality of transition region inflation lumens  138  and a guidewire lumen  104 . In a presently preferred embodiment, transition region inflation lumens  138  are in fluid communication with first lumen  118  of first shaft portion  116  and second lumen  122  of second shaft portion  120 . 
     FIG. 8 is a cross sectional view of an additional embodiment of a fused region  434 . In the embodiment of FIG. 8, core wire  56  is disposed in an offset position relative to transition region guidewire lumen  105 . As in the previous embodiment, core wire  56  passes through fused region  434  and the material of fused region  434  is disposed about a portion of core wire  56 . In the embodiment of FIG. 8, fused region  434  defines a transition region inflation lumen  138  which passes through fused region  434 . In a presently preferred embodiment, transition region inflation lumen  138 , first lumen  118 , and second lumen  122  form a portion of inflation lumen  106  of catheter  100 . 
     FIG. 9 is a cross sectional view of an additional embodiment of a fused region  534 . In the embodiment of FIG. 9, a plurality of core wires  56  pass through fused region  534 . Fused material  136  defines a transition region inflation lumen  138  which passes through fused region  534  proximate core wires  56 . Each core wire  56  is retained by fused material  136  of fused region  534 . In a presently preferred embodiment, transition region inflation lumens  138  is in fluid communication with first lumen  118  of first shaft portion  116  and second lumen  122  of second shaft portion  120 . Transition region inflation lumen  138 , first lumen  118 , and second lumen  122  may all form a portion of inflation lumen  106  of catheter  100 . 
     FIG. 10 is a cross-sectional view of an assembly  210  in accordance with the present invention. Assembly  210  includes a first shaft portion  316  having a first lumen  318  and a distal end  326 . Assembly  210  also includes a second shaft portion  320  having a second lumen  322  and a proximal end  324 . Distal end  326 .of first shaft portion  316  is disposed proximate proximal end  324  of second shaft portion  320  forming a joint  328 . In the embodiment of FIG. 10, joint  328  may be generally referred to as a butt joint. 
     In the embodiment of FIG. 10, first shaft portion  316  includes a jacket material  310  and a support member  312  comprising a plurality of filaments  314 . A support matrix  340  comprising filaments  314  extending beyond jacket material  310  is disposed within second lumen  322  of second shaft portion  320 . As shown in FIG. 10, filaments  314  extend across joint  328 . In a presently preferred embodiment, filaments  314  are adapted to reinforce joint  328 . 
     An inner tubular member or inner  330  is disposed proximate a crimp  332  formed in first shaft portion  316 . As show in FIG. 10, a portion of inner  330  is disposed within second lumen  322  defined by second shaft portion  320 . In a presently preferred embodiment, inner  330  defines a proximal guidewire port  46 , a guidewire lumen  304 , and a distal guidewire port  48  (not shown) of a catheter  300 . 
     FIG. 11 is a cross-sectional view of an assembly  211  in accordance with the present invention. Assembly  211  includes a first shaft portion  416  having a first lumen  418  and a second shaft portion  420  having a second lumen  422 . In the embodiment of FIG. 11, a support stem  442  is disposed within second lumen  422  of second shaft portion  420 . Support stem  442  is comprised of filaments  414  of support member  412  extending beyond jacket material  410  of first shaft portion  416 . In the embodiment of FIG. 11, filaments  414  of support stem  442  are arranged in a generally cylindrical shape to form support stem  442 . 
     FIG. 12 is a cross-sectional view of an assembly  212  including a first shaft portion  516  defining a crimp  532  and having a first lumen  518 . An inner  530  is disposed within crimp  532  of first shaft portion  516 . A support matrix  540  is disposed within first lumen  518  proximate crimp  532 . In a presently preferred embodiment, support matrix  540  is adapted to reinforce first shaft portion  516  proximate crimp  532 . As shown in FIG. 12, support matrix  540  is comprised of filaments  514  extending beyond jacket material  510  of first shaft portion  516 . Embodiments of assembly  212  have been envisioned in which support matrix  540  is comprised of filaments extending beyond a jacket material of second shaft portion  520 . A distal end  526  of first shaft portion  516  is disposed proximate a proximal end  524  of second shaft portion  520  forming a joint  528 . A portion of inner  530  is disposed within a second lumen  522  defined by second shaft portion  520 . 
     FIG. 13 is a cross-sectional view of an assembly  213  including a first shaft portion  616  having a first lumen  618  and a second shaft portion  620  having a second lumen  622 . In the embodiment of FIG. 13, a support stem  642  is disposed within first lumen  618  of first shaft portion  616  proximate a crimp  632  formed in first shaft portion  616 . Support stem  642  may stiffen a portion of first shaft portion  616  proximate crimp  632 . Support stem  642  is comprised of a plurality filaments  614  extending beyond jacket material  610  of first shaft portion  616 . In the embodiment of FIG. 13, filaments  614  of support stem  642  are arranged in a generally cylindrical shape to form support stem  642 . Assembly  213  also includes an inner  630 . A portion of inner  630  is disposed within second lumen  622  of second shaft portion  620 . A portion of inner  630  extending beyond second shaft portion  620  is disposed proximate crimp  632  of first shaft portion  616 . 
     FIG. 14 is a cross-sectional view of an assembly  214  forming a transition region  702  of a catheter  700  in accordance with the present invention. Assembly  214  includes a first shaft portion  716  and a second shaft portion  720 . A distal end  726  of first shaft portion  716  is disposed proximate a proximal end  724  of second shaft portion  720  forming a joint  728 . A first support matrix  748  comprising a plurality of filaments  714  is disposed within a first lumen  718  of first shaft portion  716  proximate joint  728 . A second support matrix  750  comprising a plurality of filaments  714  is disposed within a second lumen  722  of second shaft portion  720  proximate joint  728 . In a presently preferred embodiment first support matrix  748  and second support matrix  750  provide support to transition region  702  and reinforce joint  728 . In the embodiment of FIG. 14, filaments  714  comprising first support matrix  748  and second support matrix  750  extend beyond a jacket material  710  of first shaft portion  716 . Embodiments of assembly  214  have been envisioned in which first support matrix  748  and/or second support matrix  750  are comprised of filaments extending beyond a jacket material of second shaft portion  720 . 
     FIG. 15 is a cross-sectional view of an assembly  215  forming a transition region  802  of a catheter  800  in accordance with the present invention. Assembly  215  includes a first shaft portion  816  having a first lumen  818  and a second shaft portion  820  having a second lumen  822 . A first support stem  844  is disposed within first lumen  818  of first shaft portion  816 . A second support stem  846  and an inner  830  are both disposed within second lumen  822  of second shaft portion  820 . Inner  830  extends beyond second shaft portion  820  and a portion of inner  830  is disposed proximate a crimp  832  formed by first shaft portion  816 . First support stem  844  and second support stem  846  are comprised of a plurality filaments  814 . In the embodiment of FIG. 14, filaments  814  beyond a jacket material  810  of first shaft portion  816 . Embodiments of assembly  215  have been envisioned in which first support stem  844  and second support stem  846  are comprised of filaments extending beyond a jacket material of second shaft portion  820 . 
     FIG. 16 is a cross-sectional view of an assembly  216  in accordance with the present invention. Assembly  216  includes a first shaft portion  916 , a second shaft portion  920 , and an inner  930 . First shaft portion  916  includes a crimp  932  defining an opening  952 . A proximal portion  958  of inner  930  passes through opening  952  and is disposed proximate crimp  932 . Inner  930  is partially disposed within a first lumen  918  of first shaft portion  916  and a second lumen  922  of second shaft portion  920 . Second shaft portion  920  includes an enlarged portion  956  proximate the proximal end  924  thereof. A distal end  926  of first shaft portion  916  has been inserted into enlarged portion  956  of second shaft portion  920  forming a joint  928 . Joint  928  of FIG. 16 may be generally referred to as a lap joint. A method in accordance with the present invention may include the step of fusing material proximate joint  928  forming a bond between first shaft portion  916  and second shaft portion  920 . A method in accordance with the present invention may also include the step of fusing material proximate crimp  932  forming a proximal guidewire port. As shown in FIG. 16, a support matrix  940  comprising a plurality of filaments  914  is disposed within second lumen  922  of second shaft portion  920 . The presence of support matrix  940  disposed within second lumen  922  of second shaft portion  920  may increase the strength and stiffness joint  928 . A method in accordance with the present invention may include the step of fusing material proximate joint  928 . The step of fusing material, may result in a jacket material  910  of second shaft portion  920  being disposed within a plurality of interstitial openings  954  defined by support matrix  940 . A method in accordance with the present invention may also include the step of fusing material proximate crimp  932 . 
     FIG. 17 is a plan view of first shaft portion  916  of assembly  216  prior to its inclusion in assembly  216 . FIG. 17 provides an additional view of crimp  932  of first shaft portion  916  and opening  952  defined by crimp  932 . 
     FIG. 18 is a cross-sectional view of an assembly  218  in accordance with the present invention. Assembly  218  includes a first shaft portion  1016 , a second shaft portion  1020 , and an inner  1030 . First shaft portion  1016  includes a distal end  1026 , first lumen  1018 , a jacket material  1010 , and a support member  1012  comprised of a plurality of filaments  1014 . Filaments  1014  of support member  1012  extend beyond jacket material  1010  and form a support stem  1042 . Support stem  1042  and distal end  1026  of first shaft portion  1016  have been inserted into a second lumen  1022  of second shaft portion  1020 . First shaft portion  1016  also includes a crimp  1032  defining an opening  1052 . A proximal portion  1058  of an inner  1030  passes through opening  1052  and is disposed proximate crimp  1032 . The remainder of inner  1030  is disposed within a first lumen  1018  of first shaft portion  1016  and a second lumen  1022  of second shaft portion  1020 . The presence of support stem within second lumen  1022  of second shaft portion  1020  may increase the stiffness of a portion of second shaft portion  1020 . 
     FIG. 19 is a cross-sectional view of an assembly  219  in accordance with the present invention. Assembly  219  includes a second shaft portion  1120  having a second lumen  1122  and an enlarged portion  1156  proximate a proximal end  1124  thereof. Assembly  219  also includes a first shaft portion  1116  having a distal end  1126  disposed within second lumen  1122  of second shaft portion  1120  proximate enlarged portion  1156 . First shaft portion  1116  includes a crimp  1132  defining an opening  1152 . A proximal portion  1158  of inner  1130  is disposed proximate crimp  1132 . A remaining portion  1160  of inner  1130  passes through opening  1152  and is disposed within a first lumen  1118  of first shaft portion  1116  and second lumen  1122  of second shaft portion  1120 . As shown in FIG. 19, a support matrix  1140  comprising a plurality of filaments is disposed within first lumen  1118  of first shaft portion  1116 . 
     FIG. 20 is a cross-sectional view of an assembly  220  forming a transition region  1202  of a catheter  1200 . Assembly  220  includes a first shaft portion  1216  having a support member  1212 , a first lumen  1218  and a crimp  1232  defining an opening  1252  in fluid communication with first lumen  1218 . An inner  1230  is partially disposed within first lumen  1218  of first shaft portion  1216 . A proximal portion  1258  of inner  1230  passes through opening  1252  and is disposed proximate crimp  1232 . A portion of inner  1230  is also disposed within a second lumen  1222  defined by a second shaft portion  1220 . Second shaft portion  1220  includes an enlarged portion  1256  disposed proximate a proximal end  1224  thereof. A distal end  1226  of first shaft portion  1216  has been inserted into enlarged portion  1256  of second shaft portion  1220  forming a joint  1228 . As shown in FIG. 20, a support stem  1242  is disposed within first lumen  1218  of first shaft portion  1216  proximate crimp  1232 . Support stem  1242  is comprised of filaments  1214  of support member  1212  extending beyond a jacket material  1210  of first shaft portion  1216 . In the embodiment of FIG. 20, filaments  1214  of support stem  1242  are arranged in a generally cylindrical shape to form support stem  1242 . The presence of support stem within first lumen  1218  of first shaft portion  1216  may reduce the likelihood that catheter  1200  will kink proximate crimp  1232  of first shaft portion  1216 . 
     FIG. 21 is a cross-sectional view of an assembly  221  forming a transition region  1302  of a catheter  1300  in accordance with the present invention. Assembly  221  includes a second shaft portion  1320  having a second lumen  1322  and an enlarged portion  1356 . A distal end  1326  of a first shaft portion  1316  is disposed within second lumen  1322  of second shaft portion  1320  proximate enlarged portion  1356  forming a joint  1328 . First shaft portion  1316  includes a crimp  1332  defining an opening  1352 . A proximal portion  1358  of an inner  1330  is disposed proximate crimp  1332 . Inner  1330  passes through opening  1352  into first lumen  1318  of first shaft portion  1316 . Inner  1330  extends beyond first shaft portion  1316  so that a portion of inner  1330  is disposed within second lumen  1322  of second shaft portion  1320 . As shown in FIG. 21, a first support matrix  1348  comprising a plurality of filaments  1314  is disposed within first lumen  1318  of first shaft portion  1316 . A second support matrix  1350  comprising a plurality of filaments  1314  is disposed within second lumen  1322  of second shaft portion  1320 . In the embodiment of FIG. 21, filaments  1314  comprising first support matrix  1348  and second support matrix  1350  extend beyond a jacket material  1310  of first shaft portion  1316 . Embodiments of assembly  221  are possible in which first support matrix  1348  and/or second support matrix  1350  are comprised of filaments extending beyond a jacket material of second shaft portion  1320 . The presence of first support matrix  1348  disposed within first lumen  1318  of first shaft portion  1316  and second support matrix  1350  disposed within second lumen  1322  of second shaft portion  1320  may increase the strength of joint  1328 . A method in accordance with the present invention may include the step of fusing material proximate joint  1328 . The step of fusing material, may result in a jacket material  1310  of first shaft portion  1316  being disposed within interstitial openings  1354  defined by first support matrix  1348 . A jacket material  1311  of second shaft portion may be disposed within interstitial openings  1353  defined by second support matrix  1350 . A method in accordance with the present invention may also include the step of fusing material proximate crimp  1332 . 
     FIG. 22 is a cross-sectional view of an assembly  222  forming a transition region  1402  of a catheter  1400  in accordance with the present invention. Assembly  222  includes a first shaft portion  1416 , a second shaft portion  1420 , and an inner  1430 . First shaft portion  1416  includes a crimp  1432  defining an opening  1452 . A proximal portion  1458  of inner  1430  passes through opening  1452  and is disposed proximate crimp  1432 . Inner  1430  is partially disposed within a first lumen  1418  of first shaft portion  1416  and a second lumen  1422  of second shaft portion  1420 . A proximal end  1424  of second shaft portion  1420  includes an enlarged portion  1456 . A distal end  1426  of first shaft portion  1416  has been inserted into enlarged portion  1456  of second shaft portion  1420  forming a joint  1428 . As shown in FIG. 22, a first support stem  1444  is disposed within first lumen  1418  of first shaft portion  1416  and a second support stem  1446  is disposed within second lumen  1422  of second shaft portion  1420 . First support stem  1444  and second support stem  1446  are each comprised of filaments  1414  of support member  1412  extending beyond jacket material  1410  of first shaft portion  1416 . The presence of first support stem within first lumen  1418  of first shaft portion  1416  may enhance the stiffness of catheter  1400  proximate transition region  1402 . 
     Having thus described the figures, a method in accordance with the present invention may know be described with reference thereto. It should be understood that steps may be omitted from this process and/or the order of the steps may be changed without deviating from the spirit or scope of the invention. It is anticipated that in some applications, two or more steps may be performed essentially simultaneously to promote efficiency. 
     A method in accordance with the present invention may begin with the step of providing a first shaft portion, and a second shaft portion. The step of providing these shaft portions may include the step of forming a shaft portion having a lumen, a supporting member, and a layer of jacket material. The process of forming a shaft portion may include the steps of winding braiding, or knitting a plurality of filaments around an inner tube to form a support member. A layer of jacket material may then be formed over both the inner tube and the support member. In one method in accordance with the present invention, the step of forming the layer of jacket material includes the step of extruding a molten thermoplastic material onto the combined layers of the inner tube and the support member. When this process is used, the jacket material may fill any interstitial spaces in the support member. 
     A process in accordance with the present invention may include the step of stripping away a portion of the jacket material covering the filaments of the support member. The filaments may then be arranged to form one or more support elements. Many embodiments of a support element are possible without deviating from the spirit and scope of the present invention. Examples of support elements include a support matrix, and a support stem. One or more support elements may be inserted into a first lumen defined by the first shaft portion. 
     A crimp may be formed in the first shaft portion and a proximal portion of an inner may be laid in a position proximate the crimp. A distal portion of the inner may be inserted into a second lumen defined by the second shaft portion. One or more support elements may also be inserted into the second lumen defined by the second shaft portion. A distal portion of the first shaft portion may then be placed proximate a proximal portion of the second shaft portion forming an assembly having a joint. Many embodiments of a joint are possible without deviating from the spirit and scope of the present invention. Examples of joints which may be suitable in some applications include lap joints and butt joints. 
     A method in accordance with the present invention may also include the step of selectively heating one or more portions of the assembly to create one or more fused regions. In a presently preferred method, the selective heating of portions of the assembly is accomplished by illuminating selected portions of the assembly with a LASER. In one method in accordance with the present invention, the assembly is rotated while a portion thereof is illuminated with a LASER. In one method in accordance with the present invention, a portion of the material heated during the selective heating step flows into a plurality of interstitial spaces defined by the filaments of the support element. 
     Those of skill in the art will appreciate that other methods of selectively heating a portion of the assembly are possible without deviating from the spirit and scope of the present invention. Heating methods which may be suitable in some applications include convection heating, conduction heating, and radiation. An example of heating with radiant energy is directing infrared energy from an infrared heat source at the material. Infrared energy sources suitable for this process are commercially available from Research Incorporated of Minnetonka, Minn. An example of heating with conduction is touching the desired area with a heated tool. Electric heaters suitable for heating a heated tool are commercially available from Watlow Incorporated of St. Louis, Mo. An example of heating with convection is placing the assembly in a temperature chamber. Temperature chambers suitable for this process are commercially available from Thermotron Corporation of New Holland, Mich. 
     A mandrel may be inserted in the lumen of the inner to reduce the likelihood that this lumen will be closed during the selective heating step. One or more mandrels may also be inserted into the first lumen defined by the first tubular member and the second lumen defined by the second tubular member. In one method in accordance with the present invention a plurality of mandrels are utilized to define a plurality of transition region inflation lumens within the material fused during the selective heating process. In another method in accordance with the present invention, a plurality of mandrels are utilized to position a core wire within the transition region of the catheter. 
     It should be understood that steps may be omitted from this process and the order of the steps may be changed without deviating from the spirit or scope of the invention. Additional steps have also have been envisioned. For example, one envisioned method includes the step of overlaying the assembly with a sleeve. The sleeve may be PTFE shrink tubing. Suitable PTFE shrink tubing is commercially available Zeus Industries of Orangeburg, S.C. and Raychem Corporation of Menlo Park, Calif. 
     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.