Abstract:
A catheter device including an elongate tubular shaft having a consistent material composition for a substantial proportion of its length. The device includes a proximal shaft portion having a first flexibility and a distal shaft portion having a second flexibility, wherein the second flexibility is greater than the first flexibility and wherein at least the distal shaft portion comprises at least one score in a surface thereof.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. Provisional Application Ser. No. 60/668,197, filed Apr. 4, 2005, which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF INVENTION  
       [0002]     The present application relates to medical catheters, and more specifically to medical catheters useful in endovascular, biliary, and other body lumens.  
       BACKGROUND  
       [0003]     Medical delivery catheters are well known in the art of minimally invasive surgery for introduction of fluids and devices to sites inside a patient&#39;s body. For example, balloon dilation of luminal stenoses (e.g., in procedures such as angioplasty or balloon dilation of a bile duct), stent placement, and introduction of radio-opaque contrast fluids are common uses of catheters.  
         [0004]     The most widely used form of angioplasty makes use of a dilation catheter having an inflatable balloon at its distal end. In coronary procedures, a hollow guide catheter or wire guide typically is used for guiding the dilation catheter through the vascular system to a position near the stenosis (e.g., to a coronary arterial lumen occluded by plaque). Using fluoroscopy, the physician guides the dilation catheter the remaining distance through the vascular system until a balloon is positioned to cross the stenosis. The balloon is then inflated by supplying pressurized fluid, through an inflation lumen in the catheter, to the balloon. Inflation of the balloon causes a widening of the lumen of the artery to reestablish acceptable blood flow through the artery. In some cases, a stent may be deployed with or instead of the balloon to widen and hold open the occluded arterial lumen.  
         [0005]     Preferably a catheter used in endovascular lumens will have several physical characteristics. The profile and shaft size of the dilation catheter should be such that the catheter can reach and cross a very tight stenosis. Portions of the dilation catheter must also be sufficiently flexible to pass through a tight curvature or tortuous passageway, especially in a catheter adapted for use in the coronary arteries. The ability of a catheter to bend and advance effectively through the endovascular or other lumens is commonly referred to as the “trackability of the catheter.” Another important feature of a dilation catheter is its “pushability.” Pushability involves the transmission of longitudinal forces along the catheter from its proximal end to its distal end so that a physician can push the catheter through the vascular or other lumenal system and the stenoses. Effective catheters should be both trackable and pushable.  
         [0006]     Two commonly used types of dilation catheters are referred to as “long-wire” catheters and “short-wire” catheters. A long-wire catheter is one in which a wire guide lumen is provided through the length of the catheter that is adapted for use with a wire guide that can first be used to establish the path to and through a stenosis to be dilated. The dilation catheter can then be advanced over the wire guide until the balloon on the catheter is positioned within the stenosis.  
         [0007]     In short-wire catheters, the wire guide lumen does not extend the entire length of the catheter. In this type of catheter, the wire guide lumen extends only from the distal end of the balloon to a point intermediate the distal and proximal ends of the catheter. This shorter lumen is the only internal portion of the catheter contacting the wire guide. It is sometimes desirable to exchange this first catheter and/or balloon for a second catheter (e.g., to “exchange out” a balloon catheter, and then “exchange in” a stent-deployment catheter). The exchange is preferably executed by leaving the wire guide in place during removal of the first catheter and using it as a guide for the second catheter. The first catheter is withdrawn or otherwise removed over the wire guide, and then a second catheter is introduced over the wire guide.  
         [0008]     Short-wire catheters are often easier to exchange than catheters having the wire guide lumen extending the entire length of the catheter. In part, this is because the wire guide need not be as long as a “long wire” configuration, which requires that a length of the wire guide extending outside the patient&#39;s body be longer than the portion of the catheter extending over the long wire guide in order for a doctor or assistant to maintain a grasp on the wire guide (to avoid undesired movement or displacement thereof). The short wire guide configuration catheters also create less friction during mounting and exchange operations due to the shorter wire guide lumen, leading to a reduced likelihood of displacing the wire guide.  
         [0009]     Catheters for use in endovascular lumens typically require a variation in physical properties along different portions thereof. For example, a certain degree of stiffness is required for pushability and trackability near the proximal end while the distal end requires a great deal of flexibility. A catheter having uniform properties throughout its length may pose disadvantages in that it is likely to be too proximally flexible or too distally stiff. As a result, most catheter shafts (especially endovascular catheters) are made from multiple materials along the shaft length. For example, a catheter shaft may have a stiff proximal portion made of hypotube, a middle portion made of a stiff plastic, and a distal portion made of a more flexible plastic. This combination of materials poses problems of cost and efficiency in construction, and the junctions provide problematic possibilities for structural failure (such as binding, kinking, or even separation) as well as requiring specialized connection means.  
         [0010]     In another example, a catheter shaft may be made of plastic for a major part of its length, but have a stiffening wire disposed through a significant portion of that length to enhance stiffness. Some long wire catheters rely almost wholly on placement of a wire guide therethrough to retain the needed stiffness, which presents the problems of length and unwieldiness discussed above. In contrast, the proximal sections of short wire catheters must have adequate stiffness independent of the wire guide.  
         [0011]     Several different structures for shortened guide wire lumen dilation catheters have been proposed and used to obtain the desired physical properties described above, but each of these structures tends to suffer from several disadvantages. For example, in a short wire catheter having a relatively flexible one-piece plastic design, because only a small portion of the wire guide extends through the catheter body near the distal end of the catheter shaft, the wire guide portion does not contribute to the pushability of the rest of the catheter shaft. As a result, the proximal shaft portion of such a catheter has low column strength. With such a configuration, the shaft and/or guide wire may tend to develop undesirable flexure (e.g., scissoring, bowing, buckling, kinking) when the balloon is being manipulated in a lumen. This undesired flexure may cause an irregular exterior surface such as a sharp edge which can in turn cause injurious abrasions to the inner lining of the artery or other lumen (e.g. other body lumen or a working lumen of an endoscope). This undesired flexure can also lead to poor pushability and trackability of the catheter. To counteract this deficiency, some known designs have extended the length of the wire guide lumen and/or provided additional stiffener elements in the shaft.  
         [0012]     In one design, a significant proximal portion of the catheter shaft is made of a metallic tubing (commonly referred to as a hypotube), which provides the desired pushability while maintaining a relatively small outer diameter. The distal portion of the catheter shaft is a second, more flexible (commonly plastic) tubing. In short-wire catheters using the hypotube design, a first aperture for passage of a wire guide from/to the wire guide lumen is usually placed in the hypotube near to the distal end thereof. Alternatively, this first aperture is placed in the second tubing, or near the juncture between the hypotube portion and the second tubing. These types of catheters, however, present certain disadvantages. Having the first aperture in the hypotube portion mitigates the advantages of a short-wire catheter: the wire guide must be longer, and advantages conferred by reduced friction are lessened. Having the first aperture at the aforementioned junction or in the second tubing creates a likelihood of undesired flexure (e.g., kinking or bunching) as there will be at least some portion of the more flexible second tubing unsupported by a wire guide, and therefore lacking column strength. Not only may such undesired flexure injure an endovascular or other lumen housing the catheter, but it may close off an inflation lumen or other lumen of the catheter, which is undesirable.  
       BRIEF SUMMARY  
       [0013]     The present invention provides a catheter, adaptable for use in endovascular lumens, biliary lumens, or other body lumens, that has a uniform material construction for a substantial portion of its shaft length and that is adaptable for use in a short-wire or long-wire configuration. The problems of increased cost of assembly and various mechanical problems presented by constructing and using a catheter having both semi-flexible hypotube and more flexible second tubing portions of the same catheter are addressed in the present invention. The embodiments described and claimed herein provide a catheter having good pushability and trackability. In one aspect the embodiments described herein also provide a superior catheter shaft having consistent construction material throughout most of the length of the catheter shaft with gradual transition from a stiffer proximal end to a more flexible distal end and lacking sharp transitions that undermine structural integrity. The embodiments herein are also adaptable for use in a variety of minimally invasive surgical treatments (including, e.g., angioplasty or bile duct dilation).  
         [0014]     In particular, the present invention includes embodiments of a catheter device comprising an elongate tubular shaft having a consistent material composition for substantially all of its length. The tubular shaft includes a proximal shaft portion having a first flexibility and a distal shaft portion having a second flexibility, wherein the second flexibility is greater than the first flexibility and wherein at least the distal shaft portion comprises at least one score in a surface thereof.  
         [0015]     In another aspect, the invention includes a catheter device, which has an elongate tubular shaft having a consistent material composition for substantially all of its length, and a first lumen extending through at least a portion of the tubular shaft. The elongate tubular shaft includes a proximal shaft portion having a first flexibility and a distal shaft portion having a second flexibility, wherein the second flexibility is greater than the first flexibility and wherein at least the distal shaft portion comprises at least one score in a surface thereof and a distal end. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1A  is a perspective view of a first catheter device, with an enlarged detail view of the catheter&#39;s distal end;  
         [0017]      FIG. 1B  is a perspective view of a second tapered catheter device, with an enlarged detail view of the catheter&#39;s distal end;  
         [0018]      FIG. 2  is a perspective view of a third catheter shaft with a sleeve;  
         [0019]      FIG. 3A  is a perspective view of a fourth catheter device having a distal extension and an inflation balloon, with an enlarged detail view of the features at the catheter&#39;s distal end;  
         [0020]      FIG. 3B  is a perspective view of a fifth catheter device with an inflation balloon and an expandable stent;  
         [0021]      FIG. 4A  is a perspective view of a sixth catheter device having an external distal wire guide lumen structure, with an enlarged detail view of the features at the catheter&#39;s distal end;  
         [0022]      FIG. 4B  is a perspective view of a seventh catheter device having an external distal wire guide lumen structure and an inflation balloon, with an enlarged detail view of the features at the catheter&#39;s distal end;  
         [0023]      FIG. 4C  is a perspective view of an eighth catheter device with a distal dual lumen structure having a wire guide lumen structure and a mounting portion;  
         [0024]      FIGS. 5A-5B  show a side view of ninth and tenth catheter devices having a distal extension and a wire guide lumen structure;  
         [0025]      FIG. 5C  is a side view of an eleventh catheter device having an external distal wire guide lumen structure and an inflation balloon;  
         [0026]      FIG. 6  is a side view of a twelfth tapered catheter device having an external distal wire guide lumen structure and an inflation balloon;  
         [0027]      FIG. 6A  is a detail of  FIG. 6  and shows a longitudinal cross-sectional view of the tapering portion and external wire guide lumen of the twelfth catheter device;  
         [0028]      FIG. 6B  is a detail of  FIG. 6  and shows a longitudinal cross-sectional view of the distal portion of the twelfth catheter device, with an enlarged detail view of features where the catheter shaft meets the balloon;  
         [0029]      FIG. 6C  is a transverse cross-sectional view of a dual-lumen mounting sleeve; and  
         [0030]      FIG. 6D  is a transverse cross-sectional view along line  6 D- 6 D of  FIG. 6B  showing two lumens of the twelfth catheter device surrounded by a dual-lumen mounting sleeve. 
     
    
     DETAILED DESCRIPTION  
       [0031]     The presently described embodiments of a scored catheter shaft are adaptable for use in a variety of minimally invasive surgical applications (e.g. endoscopic procedures, angioplasty).  
         [0032]      FIGS. 1A-1B  illustrate an embodiment of a catheter device  100  with a shaft  101  constructed of a stainless steel hypotube material and having an internal lumen  102 . The shaft is scored in a helical fashion  105 , and the pitch between the helices decreases from the proximal end  104  toward the distal end  106 . In this embodiment, the scoring  105  is a surface scoring of the catheter shaft  101 . In alternative embodiments, at least some of the scoring may go completely through the wall of the shaft  101 . During manufacture of the shaft  101 , the scoring may be done using a laser or other appropriate cutting device. Likewise, those of skill in the art will appreciate that in alternative embodiments the tubing material may include a nickel-titanium alloy or other suitable materials.  
         [0033]     In the embodiment illustrated in  FIG. 1A , the exterior diameter  107  is substantially consistent along the length of the shaft  101 . In the embodiment shown in  FIG. 1B , the proximal end  104  has a greater exterior diameter than the distal end  106 . The catheter shaft  101  tapers toward a smaller exterior diameter  108  along the distal end  106 . Tapering can enhance flexibility of the shaft  101  in several ways. For example, flexibility is enhanced by decreasing the outside diameter of the catheter shaft  101  as shown in  FIG. 1A . The portion of the catheter shaft  101  having a smaller diameter is more flexible than the portion having a larger diameter. Such tapering also decreases the thickness of the wall of the catheter shaft  101  by tapering the outside diameter while maintaining a substantially consistent interior diameter. Alternatively, tapering may be used within the internal diameter of a catheter, enhancing flexibility by decreasing wall thickness without altering the exterior diameter of the shaft  101 . In yet other alternative embodiments, the wall thickness may be substantially constant along the shaft length, with both the inside and outside diameters being tapered. The desired steepness and location of the tapering is determined by the desired size and flexibility needed for a particular application of the catheter shaft  101 .  
         [0034]     For example, in alternative embodiments, there may be multiple stepwise or gradual differences in diameter to confer different degrees of flexibility throughout the length of the catheter. For example, a catheter shaft  101  for use in coronary arteries will typically benefit from a smaller diameter than a catheter shaft  101  for use in a bile duct, both for gross size and flexibility. A grinding process or other suitable process is used to reduce the exterior diameter as appropriate for the desired application. The flexibility of the catheter shaft  101  may also be altered by using a different construction material composition (e.g., a nickel-titanium alloy or a polymer). In the embodiment shown in the  FIG. 1B , the scoring  105  includes a plurality of parallel helices along the distal end  106 . As can be seen in the enlarged detail portion of  FIG. 1B , some of the helical scores  105  extend through the wall of the catheter shaft. Those of skill in the art will appreciate that the shaft flexibility may be increased or decreased by altering the pitch of the scoring, without significantly altering the internal and/or external diameter of the shaft.  
         [0035]     A further embodiment of the catheter shaft  101  includes a coating on internal and/or external surfaces for at least a portion of the catheter shaft  101 . The coating is selected to confer or improve one or more properties of reduced friction, flexibility, and sealing a lumen  102  of the catheter. Sealing the lumen  102  allows the lumen to be used, for example, for introduction of inflation fluid to a dilation balloon or for introduction of a medicative substance or a radio-opaque contrast fluid.  
         [0036]     The coating may be, for example, a sheath or sleeve  202  as illustrated in  FIG. 2 . In various alternative embodiments, the form of the sheath  202  may comprise, for example, an extruded sleeve, shrink tube, extruded over-jacket, or dip coat. The composition of the sheath  202  may comprise, for example, HDPE, PTFE, PEBA, PET, polyolefin, polyurethane, polyimide, nylon, or another thermoset or thermoplastic material. A PET shrink tube  202  has the advantage of providing an increased stiffness to a smaller diameter catheter shaft  201 . On the other hand, a PEBA shrink tube  202  can be used with a larger diameter catheter shaft  201  where greater flexibility is desired. The type of sleeve  202  material may also be selected to complement other catheter components; for example, a nylon sleeve  202  may bond and interact better with a nylon expandable member such as a balloon or basket, and/or with a nylon wire guide lumen. Selection of, for example, coating materials, shaft composition materials, and wall thickness allow manipulation of the catheter shaft&#39;s  201  shore hardness to offer the desired functional properties. Likewise, those of skill in the art will recognize that the method of applying a coating (e.g., over-extrusion, dip-coating, melt fusion, heat shrink lamination) may contribute to the desired properties.  
         [0037]     A sleeve or sheath  202  may confer different properties upon the shaft  201  in addition to varied hardness. For example, in the illustrated embodiment of the shaft  201  where scoring  205  extends through the shaft wall to a lumen  207 , the sheath  202  allows the lumen to be used for introducing a fluid (e.g., inflation fluid or contrast fluid) by preventing leakage along the scoring  205  in the shaft  201 . The fluid-introduction functionality is useful in embodiments where the sheath  202  is disposed on the exterior of the shaft  201  and in other embodiments where the sheath  202  is disposed inside (e.g., lining) the lumen  207  inside the shaft  201 . In embodiments where the sheath  202  is on the exterior of the shaft  201 , the sheath  202  may decrease the surface friction generated when the shaft  201  is advanced through a passage (e.g. the working lumen of an endoscope, or an endovascular lumen).  
         [0038]      FIGS. 3A-3B  illustrate embodiments of balloon catheters  300  each comprising a catheter shaft  301 . In the embodiment of  FIG. 3A , the catheter shaft  301  has an inflation balloon  304  mounted to a distal extension  302 . As can clearly be seen in the detail illustration portion of  FIG. 3A , the extension  302  houses an inflation lumen  306  which continues from the inflation lumen  306  of the catheter shaft  301 . The extension  302  also encloses a wire guide lumen  308 . In the illustrated long wire configuration catheter  300 , the wire guide lumen  308  extends from the proximal portion of the catheter shaft  301  and extends through the inflation balloon  304  at the distal end of the shaft  301 .  
         [0039]     The embodiment illustrated in  FIG. 3B  has an inflation balloon  304  disposed on the distal portion of the catheter shaft  301 . An inflation lumen  306  of the catheter shaft  301  opens into the inflation balloon  304 . A wire guide lumen  308  traverses the interior of the balloon  304 , continuing an open passage of the wire guide lumen  308  of the catheter shaft  301  to a point distal of the inflation balloon  304 . An expandable stent  312  is positioned about the balloon  304 . In an alternative embodiment, an expandable member other than a balloon (e.g., a basket) is disposed near the distal end of the catheter shaft  301 . Such an embodiment optionally may have a wire guide extending through the expandable member. At its proximal end the catheter  300  has a port  310  in fluid communication with the inflation lumen  306 . In an alternative embodiment, the port  310  offers access to the guide wire lumen  308 . The port  310  may be included in other embodiments, and in other positions on the catheter  300 . In another alternative embodiment, the catheter shaft  301  has two ports offering separate access to each of the inflation lumen  306  and the wire guide lumen  308 . In other alternative embodiments, the port  310  is useful for introducing another fluid such as a radio-opaque contrast fluid.  
         [0040]      FIGS. 4A-4B  illustrate embodiments of a catheter device  400  with a polymer shaft  401  having an external, distally disposed short wire guide lumen structure in the form of a cannula  402  having a wire guide lumen  404  disposed therethrough. The polymer shaft can be some other composition in alternative embodiments (e.g., hypotube). In  FIG. 4A , the cannula  402  is attached on the distal end  408  of the catheter shaft  401  using an adhesive. Alternative means of attachment include, for example, forced convection heating, radio frequency heating, ultrasonic welding, and laser bonding. Alternatively, shrink tubing may be used as a manufacturing aid to help compress and fuse the cannula  402  to the catheter shaft  401 . The shrink tubing may be removed and disposed of after the cannula  402  is connected to the catheter shaft  401 , or may remain on as part of the connected structure. If the catheter shaft  401  has a coating, the cannula  402  may be bonded to the coating or directly to the catheter shaft  401 . In the embodiment shown in  FIG. 4B , the cannula  402  is constructed of multifilar tubing. An inflation balloon  406  is mounted on the distal end  408  of the catheter shaft  401 . An inflation lumen  405  of the catheter shaft  401  is open to the interior of the inflation balloon  406 . The cannula  402  extends through the inflation balloon  406  and has an extension  407  on its distal end. A wire guide lumen  404  runs through the length of the cannula  402  and the extension  407 .  
         [0041]     In  FIG. 4C , the shaft  401  of the catheter device  400  is scored in a series of circumferential rings that are nearer each other along the distal-most part of the distal end  408  than along a more proximal part of the distal end  408 . There is no scoring on a substantial part of the proximal portion. This alternative embodiment of a scoring configuration provides a more flexible distal portion and a less flexible proximal portion, conferring the variance in desired stiffness as described above. A dual lumen structure  410  is disposed on the distal end  408  of the catheter shaft  401 . A portion of the length of dual lumen structure  410  has a “ FIG. 8 ” cross section. A mounting portion  412  of the dual lumen structure  410  has a lumen  414 . The distal end  408  of the catheter shaft  401  fits into the lumen  414 . The lumen  414  may be completely occupied by the distal end  408  of the catheter shaft  401 , or it may continue coaxially beyond the distal end  408  so as to form an extension in fluid communication with a lumen  420  in the shaft  401 . A wire guide portion  416  of the dual lumen structure  410  has a wire guide lumen  418  running therethrough. The dual lumen structure  410  is attached on the distal end  408  of the catheter shaft  401  using one of the attachment methods described for the embodiment shown in  FIG. 4A . In this embodiment, the lumen  414  of the dual lumen structure is in fluid communication with a lumen  404  of the catheter shaft  401 . In an alternative embodiment, a part of the mounting portion  412  is mounted inside the lumen  420  of the catheter shaft  401 .  
         [0042]      FIGS. 5A-5C  illustrate embodiments of a balloon catheter device  500  with a shaft  501  having a short wire guide configuration. The embodiments shown in  FIGS. 5A-5B  each have a coaxial extension  502  of the catheter shaft  501 , a short wire guide lumen structure in the form of a tube  504 , and an inflation balloon  506 . In the embodiment illustrated in  FIG. 5A , the proximal end  508  of the tube  504  is disposed distal of the juncture of the extension  502  with the catheter shaft  501 . The tube  504  enters the extension  502  and extends through the distal end of the balloon  506 . In the embodiment illustrated in  FIG. 5B , the proximal end  508  of the tube  504  is disposed proximal of the juncture of the extension  502  with the catheter shaft  501 . The tube  504  enters the extension  502  and extends through the distal end of the balloon  506 .  
         [0043]     The embodiment illustrated in  FIG. 5C  does not have an extension. The balloon  506  is disposed on a distal portion of the catheter shaft  501 . The proximal end  508  of the tube  504  is disposed proximal of the juncture of the extension  502  with the catheter shaft  501  and is affixed to the exterior of the catheter shaft  501 . The tube  504  passes through the middle of the balloon  506  and extends through the distal end of the balloon  506 . The shaft  501  in the embodiment of  FIG. 5C  is scored in a combination of semi-circles, semi-ellipses, spirals, and semi-spirals. In alternative embodiments, each of these scoring patterns may be used alone, in combination with each other, or with a helical scoring pattern.  
         [0044]     In each of the embodiments shown in  FIGS. 5A-5C , the placement of the proximal end  508  of the tube  504  along the catheter shaft  501  affects the flexibility of the shaft  501 . Therefore, variation in the placement is useful in increasing or reducing flexibility as desired in these and other embodiments.  
         [0045]      FIG. 6  illustrates one embodiment of a balloon catheter  600  having an elongate shaft  601 . An inflation balloon  602  is disposed near the distal end.  FIG. 6A  is an enlarged detail illustration of a middle section of the balloon catheter  600 . As shown in  FIG. 6A , the shaft  601  includes an external wire guide lumen structure  604  and an internal inflation lumen  606 . As shown in  FIG. 6A , the catheter shaft  601  is coated with a PEBA coating  603 . The coating  603  serves to reduce friction during introduction of the catheter shaft  601  and provides a seal to prevent leakage of inflation fluid from the inflation lumen  606  through the walls of the shaft  601 . As can also be seen in  FIG. 6A , the catheter shaft  601  tapers distally to a smaller diameter along the region  605 . In an alternative embodiment, a second internal lumen in addition to the inflation lumen  606  allows introduction of a fluid (e.g. contrast fluid).  
         [0046]      FIG. 6B  is an enlarged detail illustration of a distal section of the balloon catheter  600 . As shown in  FIG. 6B , the inflation lumen  606  opens into the inflation balloon  602 , and the wire guide lumen  604  extends through the balloon  602  to the distal end  607 .  FIG. 6B  includes an enlarged detail portion more clearly illustrating the relationship between the balloon  602  and the two lumens ( 604  and  606 ). In this embodiment, the balloon  602  and wire guide lumen  604  are mounted to the shaft  601  with a PEBA shrink sleeve  608 . As shown in  FIG. 6C , a cross-sectional view of the sleeve  608  has approximately a figure-eight shape before mounting. The sleeve  608  has two central apertures ( 610  and  612 ) to allow mounting the sleeve  608  over the wire guide lumen  604  and the shaft. In this embodiment, after the balloon  602  and wire guide  604  are assembled to the shaft  601  together with the sleeve  608 , the sleeve  608  is heated to shrink and form to the assembly of shaft  601 , balloon  602 , and wire guide  604 .  FIG. 6D  is a transverse cross section along line  6 D- 6 D of  FIG. 6B , and shows the finished configuration. The sleeve  608  forms to the shaft  601  and leaves open the inflation lumen  606  and the wire guide lumen  604 . In alternative embodiments, the shaft coating (if any) may be a material other than PEBA, and may be the same or different than the material in a mounting sleeve used to mount a balloon.  
         [0047]     It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.