Abstract:
A rapid exchange stent delivery catheter which includes an inner tubular member and an outer tubular member slidably disposed thereon. The inner tubular member and the outer tubular member have rapid exchange type guide wire openings. The guide wire opening of the outer tubular member is preferably shorter in length than the guide wire opening of the inner tubular member to protect the inner workings of the catheter. The outer tubular member may include a guide wire access sleeve having a guide wire ramp extending into the guide wire lumen of the inner tubular member. The guide wire sleeve may be a separate component from the remainder of the outer tubular member to facilitate efficient manufacture.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to stent delivery catheters, such as biliary stent delivery catheters. More specifically, the present invention relates to rapid exchange type stent delivery catheters for delivering a self-expanding stent to a bodily lumen, such as the biliary tract.  
         BACKGROUND OF THE INVENTION  
         [0002]    Endoscopic procedures for treating abnormal pathologies within the alimentary canal system and biliary tree (including the biliary, hepatic, and pancreatic ducts) are increasing in number. The endoscope provides access to the general area of a desired duct using direct visualization. However, the duct itself must be navigated using a catheter in conjunction with a guidewire under fluoroscopy. A wide variety of catheters are known for treatment of such targeted anatomical regions. Examples of biliary catheters are disclosed in U.S. Pat. No. 5,921,971 to Agro et al. and PCT International Publication No. 00/69498 to De Toledo et al., the disclosures of which are hereby incorporated by reference.  
           [0003]    Agro et al. &#39;971 discloses a catheter for use in biliary procedures, wherein the catheter includes a shaft having a proximal end and a distal end. A guidewire lumen extends through the shaft from a proximal guidewire port located proximal of the distal end of the shaft, to a distal guidewire port located at the distal end of the shaft. The shaft may also include a slot or channel extending from a proximal end of the shaft to the proximal guidewire port. Catheters incorporating such a guidewire opening and channel are often referred to as rapid exchange or single operator exchange type biliary catheters.  
           [0004]    De Toledo et al. &#39;498 discloses single operator drainage catheter delivery system including a guide member having a guidewire lumen extending through a distal portion thereof, with a proximal guidewire port located distal of the proximal end. A placement catheter is disposed over the guide member has a catheter lumen extending through a distal portion thereof, with a proximal guidewire port located distal of the proximal end. Locating the proximal guidewire ports as such allows the delivery system to be used by a single person with a shorter guidewire. A drainage catheter (a.k.a. a plastic stent) is disposed about the guide member distal of the placement catheter. The drainage catheter delivery system preferably includes a means for releasably connecting the placement catheter to the drainage catheter, wherein the releasable connecting means disconnects the drainage catheter upon displacement of the guide member. However, De Toledo et al. &#39;498 does not disclose a rapid exchange biliary catheter system for the delivery of a metallic self-expanding stent, which requires a retractable sheath.  
           [0005]    U.S. Pat. No. 5,484,444 to Braunschweiler et al., and U.S. Pat. No. 5,709,703 to Lukic et al. disclose a stent delivery device which has an elongated sheath with a self-expandable stent placed in contracted condition within the distal area of the sheath. An elongated core is arranged in the sheath for longitudinal motion relative to the sheath to facilitate stent delivery. However, Braunschweiler et al. &#39;444 and Lukic et al. &#39;703 do not provide a rapid exchange feature as in De Toledo et al. &#39;498.  
           [0006]    U.S. Pat. No. 5,743,874 to Fischell et al. discloses a catheter capable of performing balloon angioplasty followed by delivery of a self-expanding stent. The catheter includes an outer sheath which may be pulled back to deploy the self-expanding stent. In one embodiment, the catheter includes a guide wire entry port located just proximal of the stent to permit rapid exchange capability. To provide the guide wire entry port, Fischell et al. &#39;874 provides a sloped plug disposed in the inner tube and an elongate side opening in the outer sheath. The elongate side opening in the outer sheath is necessary to permit retraction of the outer sheath for stent deployment. By providing such a long side opening, a major portion of the inner workings of the catheter are exposed to bodily fluids and interference from other devices, which may compromise performance of the stent delivery catheter. This undesirable feature, in addition to others not specifically mentioned herein, leaves a need for an improved rapid exchange stent delivery catheter.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides an improved rapid exchange catheter system for the delivery of a self-expanding stent to a bodily lumen (e.g., biliary tract, blood vessel, etc.), such as a metallic biliary stent commercially available from Boston Scientific Corporation under the trade name Wallstent™. In an exemplary embodiment, the rapid exchange stent delivery catheter includes an inner tubular member and an outer tubular member slidably disposed thereon. The inner tubular member has a guide wire lumen with a proximal rapid exchange type guide wire opening. The outer tubular member also has a rapid exchange type guide wire opening that is preferably shorter than the guide wire lumen of the inner tubular member in order to protect the inner workings of the catheter from bodily fluids and other devices.  
           [0008]    The outer tubular member may include a guide wire access sleeve in which the guide wire opening is disposed. The guide wire access sleeve has a guide wire ramp extending into the guide wire lumen of the inner tubular member. The guide wire sleeve may be a separate component from the remainder of the outer tubular member to facilitate efficient manufacture. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a plan view of a rapid exchange stent delivery catheter system in accordance with an exemplary embodiment of the present invention, shown in the delivery state;  
         [0010]    [0010]FIG. 2 is a plan view of a distal portion of the rapid exchange stent delivery catheter system illustrated in FIG. 1, shown in the deployment state;  
         [0011]    [0011]FIG. 3 is a plan view of a distal portion of the outer tubular member of the rapid exchange catheter illustrated in FIG. 1;  
         [0012]    [0012]FIG. 4 is a plan view of an inner tubular member of the rapid exchange catheter illustrated in FIG. 1;  
         [0013]    [0013]FIGS. 5A and 5B are cross-sectional views taken along lines  5 A- 5 A and  5 B- 5 B, respectively, in FIG. 4;  
         [0014]    [0014]FIG. 6 is a plan view of a self-expanding metallic stent suitable for delivery by the rapid exchange catheter illustrated in FIG. 1;  
         [0015]    [0015]FIG. 7A is an isometric view of a guide wire sleeve of the outer tubular member illustrated in FIG. 3; and  
         [0016]    [0016]FIG. 7B is a longitudinal sectional view of the guide wire sleeve illustrated in FIG. 7A. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. Those skilled in the art will recognize that the dimensions and materials discussed herein are merely exemplary and are not intended to limit the scope of the present invention.  
         [0018]    Refer now to FIGS. 1 and 2 which illustrate plan views of a rapid exchange stent delivery catheter system  10  in accordance with an embodiment of the present invention. The rapid exchange stent delivery catheter system  10  includes a rapid exchange catheter  100  which is advanced over a guide wire  30  (shown in phantom) to deliver and deploy a self-expanding stent  20  in a bodily lumen.  
         [0019]    The rapid exchange stent delivery catheter system  10  is suitable for biliary applications and intravascular applications. In biliary applications, the rapid exchange stent delivery catheter system  10  is sized to fit within an endoscope (not shown) and to navigate to the desired site in the biliary tract. In vascular applications, the rapid exchange stent delivery catheter system  10  is sized to fit within an introducer sheath (not shown) and/or a guide catheter (not shown) to navigate to the desired vascular site.  
         [0020]    The rapid exchange stent delivery catheter  100  includes an inner tubular member  120  slidably disposed in an outer tubular member  140 . The outer tubular member  140  includes a lumen (not visible) extending therethrough to slidably accommodate the inner tubular member  120 . The inner tubular member  120  includes a guide wire lumen  130  extending through a distal portion thereof to accommodate the guide wire  30 .  
         [0021]    To provide rapid exchange capability for the rapid exchange stent delivery catheter  100 , the guide wire  30  exits through a guide wire opening  170  in the outer tubular member  140  as will be discussed in greater detail with reference to FIGS. 3, 7A and  7 B. The guide wire  30  extends through a relatively short guide wire lumen and enters through a distal guide wire opening in the inner tubular member  129 , as will be discussed in greater detail with reference to FIGS. 4, 5A and  5 B. In practice, the device  100  may be inserted over the guide wire  30  from the tip end first.  
         [0022]    A proximal handle  122  is connected to a proximal portion  124  of the inner tubular member  120 . Similarly, a distal handle  142  is connected to a proximal portion  144  of the outer tubular member  140 . The distal handle  142  may be longitudinally displaced relative to the proximal handle  122  to selectively expose or cover the self-expanding stent  20 , which is disposed about a distal portion of the inner tubular member  120 . In FIG. 1, the distal handle  142  has been longitudinally displaced in the distal direction relative to proximal handle  122  such that the outer tubular member  140  covers the self-expanding stent  20 . In FIG. 2, the distal handle  142  has been longitudinally displaced in the proximal direction relative to proximal handle  122  to retract the outer tubular member  140  relative to the inner tubular member  120  to expose and deploy the self-expanding stent  20 .  
         [0023]    With additional reference to FIG. 3, the outer tubular member  140  includes, from the proximal end to the distal end, a proximal portion  144 , a main outer portion (not visible) a guide wire sleeve  160  and a distal outer portion  146 . The proximal end of the proximal outer portion  144  is connected to the distal handle  142 . The distal handle  142  may be injection molded over the proximal outer portion  144 . The distal end of the proximal outer portion  144  is connected to the proximal end of the main outer portion (not visible). The distal end of the main outer portion (not visible) is connected to the proximal end of the guide wire sleeve  160 , and the distal end of the guide wire sleeve  160  is connected to the proximal end of the distal outer portion  146 . The various portions of the outer tubular member  140  may be connected by adhesive, by thermal means or by any other suitable means known to those skilled in the art.  
         [0024]    The proximal outer portion  144  may be formed of PEBAX, having a length of approximately 8.0 inches (20.3 cm), an outside profile of approximately 0.120 inches (9F) (0.30 cm), and an inside diameter of approximately 0.083 inches (0.21 cm). The guide wire sleeve  160  is discussed in greater detail with reference to FIGS. 7A and 7B. The main outer portion (not visible) may be formed of PEBAX/wire braid/PTFE composite, having a length of approximately 55.0 inches (0.140 cm), an outside profile of approximately 6F (0.079 inches), and an inside diameter of approximately 0.057 inches (0.145 cm). The distal outer portion  146  may be formed of PEBAX/wire braid/PTFE composite, having a length of approximately 10.6 inches (27 cm), an outside profile of approximately 8F 0.105 inches, and an inside diameter of approximately 0.090 inches (0.229 cm).  
         [0025]    A radiopaque marker band  42  may be disposed adjacent the distal end of the distal outer portion  146  to facilitate radiographic placement of the catheter  100  and to radiographically indicate the position of the outer tubular member  140  relative to the inner tubular member  120  to aid in deploying the self-expanding stent  20 .  
         [0026]    With additional reference to FIGS. 4, 5A and  5 B, the inner tubular member  120  includes a distal inner portion  126  connected to the distal end of the proximal inner portion  124 . The proximal inner portion  124  and the distal inner portion  126  are esstentially the same, except the proximal inner portion  124  is reinforced with a SST hypotube. The inner portions  124 / 126  may be formed of PEEK, having a length of approximately 88.6 inches (225 cm), an outside profile of approximately 0.052 inches (0.13 cm), and an inside diameter of approximately 0.037 inches (0.094 cm). A jacket formed of LDPE, having a length of approximately 5.9 inches (15 cm), an outside profile of approximately 0.80 inches (0.020 cm), and an inside diameter of approximately 0.055 inches (0.14 cm) may be disposed about the inner member  120  to consume the clearance between the inner member  120  and the outer member  140  proximal of the stent  20  to prevent kinking. The various portions of the inner tubular member  120  may be connected by adhesive, by thermal means or by any other suitable means known to those skilled in the art.  
         [0027]    A distal head  132  is connected to the distal end of the distal inner portion  126  to limit distal displacement of the outer tubular member  140 . A distal bond region  134  is disposed immediately proximal of the distal head  132 . A holding sleeve  136  and a stent cup  138  prevent slippage of the stent  20 . Radiopaque marker bands  44 / 48  are disposed on the distal inner portion  126  and are separated by a distance approximately equal to the length of the stent  20 . The distal outer portion  146  of the outer tubular member  140  contains the self-expanding stent  20  during delivery.  
         [0028]    The distal inner portion  126  includes a proximal guide wire opening  128  and a distal guide wire opening  129 . A guide wire lumen  130  extends between the proximal guide wire opening  128  and the distal guide wire opening  129  to accommodate the guide wire  30  therein. The proximal guide wire opening  128  has a length which is greater than the length of the guide wire opening  170  of the guide wire sleeve  160 . The length of the proximal guide wire opening  128  is sufficient to allow longitudinal displacement of the outer tubular member  140  relative to the inner tubular member  120  to permit full exposure and deployment of the self-expanding stent  20 . The length of the proximal guide wire opening  128  is preferably slightly longer than the length of the constrained portion of the stent  20  to avoid wedging the guide wire  30  between the inner tubular member  120  and the outer tubular member  140  prior to full deployment of the stent  20 .  
         [0029]    The guide wire lumen  130  may be eccentrically positioned in the distal inner portion  126  as seen in FIGS. 5A and 5B. For example, the upper wall may have a thickness of approximately 0.003 inches and the lower wall may have a thickness of approximately 0.011 inches. The upper thinner wall portion may be removed (skived) to define the proximal guide wire opening  128 . By removing only the thin-walled portion of the distal inner portion  126 , the column strength of the inner tubular member  120  is not significantly compromised.  
         [0030]    A solid mandrel (not shown) may be inserted into the proximal lumen (not visible) of the inner tubular member  120  proximal of the guide wire opening  128  for improved column strength. The solid mandrel may be formed of stainless steel having an outside diameter of approximately 0.030 inches with a tapered end. A stainless steel hypotube (not shown) having an outside diameter of approximately 0.079 inches may be disposed about the proximal inner portion  124  for added column strength and durability. The proximal handle  122  may be injection molded over the proximal end of the hypotube and the proximal end of the proximal inner portion  124 .  
         [0031]    A distal radiopaque marker  44  is disposed on the distal inner portion  126  to radiographically mark the distal end of the stent  20 . A proximal radiopaque marker  48  is disposed on the distal inner portion  126  to radiographically mark the proximal end of the stent  20 . A mid radiopaque marker  46  is disposed on the distal inner portion  126  distal of the holding sleeve  138  to radiographically facilitate deployment of the stent  20 .  
         [0032]    With reference to FIG. 6, the stent  20  may comprise any self-expanding stent suitable for biliary or intravascular applications. For example, in biliary applications, the self-expanding stent  20  may comprise a metallic stent commercially available from Boston Scientific Corporation under the trade name Wallstent™.  
         [0033]    With reference to FIGS. 7A and 7B, the guide wire sleeve  160  includes a proximal portion  164 , a distal portion  162  and a lumen  166  extending therethrough. The distal portion  162  is flared to fit over and be connect to the distal outer portion  146 . The proximal portion  164  is sized to fit within and be connected to the main outer portion.  
         [0034]    A guide wire opening  170  extends through the exterior wall of the guide wire sleeve  160 . A ramp  172  extends from the exterior wall into the lumen  166 . When assembled, the ramp  172  extends through the proximal guide wire opening  128  of the inner tubular member  120  and into the guide wire lumen  130 . The ramp  172  is moveable within the proximal guide wire opening  128  to facilitate a smooth transition of the guide wire  30  from the guide wire lumen  130  to exterior of the catheter  100 , regardless of the position of the outer tubular member  140  relative to the inner tubular member  120 .  
         [0035]    The guide wire sleeve  160  may have a length of approximately 1.0 inch, a distal outside diameter of approximately 0.122 inches, a proximal outside diameter of approximately 0.087 inches, a distal inside diameter of approximately 0.107 inches, and a proximal inside diameter of approximately 0.070 inches. The ramp  172  may be an intrigal extension of the exterior wall of the guide wire sleeve  160  and may have a length of approximately 0.090 inches and a width of approximately 0.50 inches. The ramp  172  may extend into the lumen  166  at an angle of approximately 30 degrees to a point approximately 0.14 inches away from the opposite wall.  
         [0036]    The guide wire sleeve  160  may be an intrigal part of the outer tubular member  140  but is preferably a separately manufactured component. For example, the guide wire sleeve  160  may be formed of injection molded nylon or polypropylene. If the guide wire sleeve  160  is injection molded, manufacturing artifacts such as hole  168  may be filled or removed depending on the particular application. By manufacturing the guide wire sleeve  160  separately, more manufacturing flexibility and efficiency are achieved. For example, the guide wire sleeve  160  may be made of a material that is not melt sensitive or that is readily bonded to facilitate connection to other catheter components using adhesive or thermal means. In addition, the guide wire sleeve  160  may be inspected prior entering the production floor to eliminate non-conforming parts and increase efficiency. Further, the dimensions may be controlled better to provide greater consistency at bond sites. These and other advantages not specifically mentioned herein may be obtained by manufacturing the guide wire sleeve  160  as a separate component, but such is not essential to the present invention.  
         [0037]    Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departures in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.