Abstract:
A rapid exchange catheter comprises a guide wire lumen including a substantially sealed portion in which a lumen wall extends around an entire periphery thereof and a channel portion including a channel opening the lumen to an exterior of the catheter, wherein a width of the channel is less than a maximum width of the channel portion. A guide wire ramp extends into the channel portion, with the ramp extending further into the lumen of the channel portion as a distal end of the ramp is approached.

Description:
RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 12/437,281 filed May 7, 2009, now U.S. Pat. No. 8,388,876, which is a divisional of U.S. patent application Ser. No. 10/268,135 filed Oct. 8, 2002, now U.S. Pat. No. 7,534,223, the entire disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND INFORMATION 
     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 fluoroscopy and guide wires. 
     If visualization of the common bile duct is desired, the guide wire is guided into the common bile duct and the catheter is advanced over the guide wire until the distal end thereof is positioned at a desired location for delivery of the contrast media for fluoroscopic visualization of the anatomical detail within the common bile duct. 
     Visualization may reveal selected areas within the common bile duct that require treatment. To treat the selected areas, a different catheter is typically required, necessitating a catheter exchange. A catheter exchange typically involves removing the first catheter from the endoscope, over the guide wire, and advancing a second catheter over the guide wire to the desired treatment site. Once the guide wire is in place relative to the targeted area, it is highly desirable to maintain the position of the guide wire during subsequent catheter procedures, including during a catheter exchange procedure. If the guide wire moves during such a procedure, the guide wire may need to be re-directed through the body ducts to the target site, which is often a difficult and time consuming task. 
     In addition to performing a catheter exchange procedure, it may be desirable at times to perform a guide wire exchange procedure, for example, when a first guide wire is too large to fit through a desired body duct, or otherwise lacks the characteristics desired for a particular application. Under these circumstances, a physician may leave the catheter in place and withdraw the first guide wire from the catheter. The physician then inserts a second guide wire through the catheter to the desired site. Thus, once the catheter has been properly positioned at a target site, it is highly desirable to maintain the position of the catheter during a guide wire exchange procedure so that the second guide wire may be guided directly to the desired site. 
     To maintain the position of the guide wire and/or catheter, a physician typically must grasp the proximal end of the guide wire and/or catheter with one hand and perform the corresponding exchange with the other. This is difficult, and often results in the movement of the guide wire and/or catheter. Alternatively, additional devices such as guide wire extenders may be used. However, utilizing such additional devices adds to the complexity of and the time required for the exchange. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a rapid exchange catheter comprises a guide wire lumen including a substantially sealed portion in which a lumen wall extends around an entire periphery thereof and a channel portion including a channel opening the lumen to an exterior of the catheter, wherein a width of the channel is less than a maximum width of the channel portion. A guide wire ramp extends into the channel portion, with the ramp extending further into the lumen of the channel portion as a distal end of the ramp is approached. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows an exemplary embodiment of a catheter according to the present invention in a perspective view having a C-shaped channel and guide wire lumen for directing a guide wire along its shaft and for facilitating rapid catheter exchange; 
         FIG. 2  shows a cross-sectional view of the catheter of  FIG. 1  taken along the line  2 - 2  thereof; 
         FIG. 3  shows a cross-sectional view of the catheter with the guide wire of  FIG. 1  taken along the line  3 - 3  thereof; 
         FIG. 4  shows a cross-sectional view of the catheter with the guide wire of  FIG. 1  taken along the line  4 - 4  thereof; 
         FIG. 5  shows a partially cross-sectional perspective view of the catheter of  FIG. 1  showing the formed guide wire ramp thereof taken along the line  4 - 4  of  FIG. 1 ; and 
         FIG. 6  shows a cross-sectional view of the catheter of  FIG. 1  taken along a longitudinal axis thereof. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-6  show an exemplary embodiment of a catheter assembly  30  according to the present invention. The catheter assembly  30  is used in catheter procedures for accessing targeted anatomical regions through the alimentary canal. The present invention incorporates features that allow rapid exchange of a catheter by a single operator. The catheter of the present invention allows shorter length guide wires to be used, resulting in procedures which require less medical personnel, are less time consuming, and less costly. Additionally, the present invention is adaptable to a variety of catheter devices used for catheter procedures within the alimentary canal or any other is body lumen. 
     The catheter assembly  30  includes a catheter hub assembly  32  and a catheter  34 , having a guide wire  36  passing through a guidewire lumen  60 , (shown in  FIGS. 2 and 3 ) extending therethrough. The catheter  34  includes a shaft  38  which has a proximal end  40 , a C-channel  42 , a distal tip region  44 , a distal end  46  and various lumens described in greater detail below. The catheter hub assembly  32  is operably connected to a proximal end  40  of the shaft  38 . The catheter hub assembly  32  is preferably configured to couple to ancillary devices allowing access to a lumen within the shaft  38 . 
     The shaft  38  may preferably be a generally tubular member having a generally uniform outer shape at the proximal end  40 . As would be understood by those of skill in the art, the shaft  38  may be sized for slidable passage through the lumen of an endoscope (not shown) or through a body lumen. The shaft  38  is preferably formed in an extrusion process, and may be formed of a polymeric material. In one embodiment, the preferred polymeric material is polytetrafluoroethylene, polyether block amide, nylon or a combination or blend of these. Catheters that are contemplated include, but are not limited to, cannulas, sphincterotomes, cytology devices, and devices for stone retrieval and stent placement. 
     In a preferred embodiment, the shaft  38  may further include a distal taper  48  that tapers to the distal tip region  44 . Additionally, the distal tip region  44  may, for example, include high contrast, color-coded distal markers  50 . Finally, the distal end  46  may be radiopaque for fluoroscopic visualization of the distal tip region  44  during a catheter procedure. 
     The guide wire lumen  60  extends through the catheter  34  from a proximal end to a distal end thereof. The C-channel  42  forms a portion (e.g., a channel portion) of the guide wire lumen  60 , extending between a channel proximal end  52  and a channel distal end  54 . The C-channel  42  serves to contain, but not necessarily constrain, the guide wire  36  therein. In contrast to some catheters that include channels that are substantially “U” shaped, the C-channel  42  is shaped substantially like a letter “C”. That is, sides of the C-channel extend inward from a maximum diameter to partially close the channel, as shown more clearly in  FIGS. 4 and 5 . The “C” shape allows radial removal of the guide wire  36  from the C-channel  42  via a slot  42 ′ (e.g., a channel opening) extending between the walls of the C-channel  42  and opening an interior of the guide wire lumen  60  to an outside of the catheter  34 . At the same time, the “C” shape of the C-channel, increases the overall strength of the shaft  38  compared with catheters that have a “U” shaped channel. The increased strength of the shaft allows for greater force to be used in pushing the catheter  34  into the body. The “C” shape of the C-channel also leaks less bodily fluid as compared to catheters that have a “U” shaped channel. 
     In a preferred embodiment, the C-channel  42  is sufficiently large to allow unhindered radial removal of the guide wire  36  from the C-channel  42  via the slot  42 ′. Further, the walls of the C-channel  42  and the slot  42 ′ may be formed to be substantially equal in size to or slightly larger than a diameter of a guide wire to be used with the catheter  34 , as described in greater detail below. Although it is recognized that the channel proximal end  52  may be located at any location distal of the proximal end  40  of the shaft  38 , the channel distal end  54  is preferably located between 10 and 40 cm from the distal end  46  of the catheter shaft  38 . The channel distal end  54  may-more preferably be located between 20 and 30 cm and, most preferably, approximately 25 cm from the distal end  46 . 
     As shown in  FIG. 2 , proximal to the channel proximal end  52  and a beginning at a sealed proximal portion  52 ′, the guide wire lumen  60  is completely sealed from an outside of the catheter  34 . As shown in  FIGS. 4 and 5  and described more fully below, the portion of the guide wire lumen  60  between the channel proximal and distal ends  52 ,  54 , respectively, (i.e., the C-channel  42 ) is open to the outside of the catheter  34  via the slot  42 ′. The catheter  34  according to this exemplary embodiment also includes ancillary lumens  56  and  58  which may be used for a variety of purposes as would be understood by those of skill in the art.  FIG. 3  shows a guide wire  36  received in the distal portion of the guide wire lumen  60 . Beginning at a sealed distal portion  54 ′, this portion of the guide wire lumen  60  is also completely sealed from an outside of the catheter  34 . 
     As would be understood by those of skill in the art, the ancillary lumens  56  and  58  may preferably extend longitudinally between the proximal end  40  and the distal end  46  of the shaft  38  so that they may be used, for example, as injection lumens, allowing for high contrast media flow capability for bubble-free opacification and for visualization of a desired anatomical region. Additionally or alternatively, the ancillary lumens  56  and  58  may, for example, be used for or serve as part of another ancillary device, such as a cutting wire or a retrieval balloon, etc. 
     The guide wire lumen  60  preferably extends longitudinally between the proximal end  40  and the distal end  46  of the shaft  38  in the preferred embodiment and is sized to receive the guide wire  36  slidably therein. As would be understood, the guide wire lumen  60  may be formed integrally with the catheter shaft  38 . Alternatively, the guide wire lumen  60  may be a separate tubular member coupled to the catheter shaft  38 . In one preferred embodiment, the guide wire lumen  60  is a tubular member which is located proximate the distal end  46  of the shaft  38 . It is recognized, though, that the guide wire lumen  60  may be formed anywhere along the shaft  38 , and may comprise an extension of the shaft  38  coupled to the distal end  46  thereof. Alternatively, it may run the entire length of the shaft  38 . 
     As shown in  FIGS. 5 and 6 , a guide wire ramp  62  is formed by a portion of the wall above the guide wire lumen  60 . As would be understood by those of skill in the art, the ramp  62  may, for example, be formed by a cut  62 ′ in a portion of the wall of the guide wire lumen  62  extending at an angle from the slot  42 ′ distally for a predetermined length. The substantially triangular portion of the wall which will form the ramp  62  may then be forced into the guide wire lumen  60  and formed as a ramp by, for example, application of a heated mandrel thereto. Those skilled in the art will understand that this same structure may also be created using, for example, a direct molding process, ultrasonic welding or other known techniques. Thus, a pointed end  62 ″ of the ramp  62  will extend into the guide wire lumen  60  with the rest of the surface of the ramp  62  extending upward therefrom to the outer surface of the catheter  34 . 
     In use, when a guide wire  36  has been previously positioned at a desired location within the body, the physician simply inserts the proximal end of the guide wire  36  into the guide wire lumen opening at the distal end of the catheter  34  and slides the catheter  34  distally along the guide wire  36  while gripping the portion of the guide wire  36  extending distally of the distal end of the catheter  34  to retain the guide wire  36  in the desired position. When the proximal end of the guide wire  36  contacts the end  62 ″ of the ramp  62 , the proximal end of the guide wire is deflected out of the guide wire lumen  62  through the slot  42 ′. The physician may then grasp the proximal end of the guide wire  36  and continue to slide the catheter  34  along the guide wire  36  until the desired location is reached. As the guide wire  36  is received within the guide wire lumen  60  only along a short portion of the length of the catheter  34 , those skilled in the art will understand that the physician may at all times maintain his grasp on an exposed portion of the guide wire  36  to maintain it in position without the need for guide wire extenders. 
     If, thereafter, the catheter  34  is to be exchanged for another, the physician simply draws the catheter  34  proximally along the guide wire  36  while grasping the proximal end of the guide wire  36 . When the distal end of the catheter  34  exits the body, the physician may grasp the portion of the guide wire  36  extending distally of the catheter  34  and remove the catheter  34  completely from the guide wire  36 . The loading process described above may then be repeated for the new catheter  34  to be used. If, however, the physician wishes to exchange the guide wire  36  while maintaining the catheter  34  in a desired position within the body, the following steps are performed. First, while grasping the proximal end of the catheter  34 , the physician draws the guide wire  36  proximally out of the guide wire lumen  60  and removes it from the body. Then, the new guide wire  36  is inserted into the channel proximal end  52  and is fed through the guide wire lumen  60  through the C-channel  42  so that it deflects the ramp  62  radially outward to allow the guide wire  36  to pass thereunder, past the channel distal end  54  and out of the distal end of the catheter  34 . 
     If a guide wire  36  has been inserted into the catheter  34  from the proximal end  40 , through the C-channel  42  to the distal end  46  and this catheter  34  later needs to be exchanged while maintaining the guide wire  36  in position, the physician grasps the proximal end of the guide wire  36  to maintain it in position and slides the catheter  34  proximally along the guide wire  36  until the channel proximal end  52  is located outside the body. The physician may then grasp the guide wire  36  via the channel proximal end  52  or the slot  42 ′ and draw the proximal end of the guide wire  36  distally through the proximal portion of the guide wire lumen  60  while holding the distal portion of the guide wire  36  stationary to maintain the position of the distal end of the guide wire  36 . When the proximal end of the guide wire  36  has been removed from the guide wire lumen  60 , the catheter  34  may be drawn proximally from the body with the guide wire  36  sliding out of the C-channel  42  via the slot  42 ′. When the distal end of the catheter  34  is outside the body, the physician grasps the portion of the guide wire  36  extending distally of the distal end of the catheter  34  and withdraws the catheter  34  from the guide wire  36 . 
     Furthermore, as described above in regard to the exemplary embodiment, the strength of the catheter  34  is improved by cutting into only one side of the slot  42 ′ to form the guide wire ramp  62 . The guide wire lumen  60  and the C-channel  42  allow rapid exchange of the catheter assembly  30  when an alternative catheter is necessary during a medical procedure and make it possible to use a shorter guide wire  36  when the guide wire  36  exits the catheter  34  at the channel distal end  54  rather than the proximal end  40 . 
     The present invention may be used, for example, in the treatment of pathologies within a patient&#39;s biliary tree. Generally, for the treatment of pathologies within the patient&#39;s biliary tree an endoscopic biliary procedure is performed. Methods and devices for using biliary catheters to perform such catheter procedures are disclosed in Weaver et al., U.S. Pat. No. 5,397,302 and Karpiel, U.S. Pat. No. 5,320,602, the disclosures of which are expressly incorporated by reference herein. In an endoscopic biliary procedure, the endoscope is introduced into the mouth of a patient and guided down the patient&#39;s alimentary canal through the esophagus, the stomach, and past the pyloric sphincter of the stomach into the duodenum. 
     Prior to positioning the guide wire  36  within the patient, the catheter assembly  30  is fed into an endoscope and advanced to the opening of the bile duct under visual observation via the endoscope. The catheter  30  is then advanced through the sphincter to enter the bile duct. At this point, a distal end of the guide wire  36  is inserted into the guide wire lumen  60  via the channel proximal end  52  and passed therethrough to the catheter distal end  46 . As the guide wire  36  passes through the C-channel  42 , it encounters the ramp  62  and deflects the distal end  62 ″ of the ramp  62  radially outward while passing through the lumen  60  to the distal end  46  of the catheter  34 . The distal end of the guide wire  36  is then located within the bile duct where it may be guided to the target location using known techniques. As would be understood by those of skill in the art, if desired, the distal end of the guide wire  36  may alternatively be fed into the guide wire lumen  60  through the catheter hub assembly  32  and into the proximal end  40  of the catheter  34  and from there to the distal end  46 . However, this reduces the effectiveness of the rapid exchange features of the catheter  34  according to the present invention. 
     In one method, the guide wire  36  is advanced until its distal tip is positioned within the target area in the biliary tree. For example, the distal tip of the guide wire  36  may be guided through the orifice leading to the papilla of vater for access to the biliary tree. The catheter shaft  38  may then be advanced over the guide wire  36 , tracking the catheter assembly  30 , until the catheter distal tip region  44  exits the distal end of the endoscope and is positioned within the desired duct. In another method, the guide wire  36  and the catheter assembly  30  are advanced together until the catheter distal end  44  is positioned at the target area. In a third possible method, the catheter assembly  30  is first advanced to near the target area. The guide wire  36  may then be inserted when needed to further advance the catheter  34 . 
     Once the guide wire  36  has been positioned at the target area, catheter procedures may be performed. For example, contrast media, such as radiopaque dye, may be injected through the ancillary lumens  56  or  58  into the common bile duct for visualization of the duct. After the desired catheter procedure has been completed, the catheter assembly  30  may be exchanged or removed from the endoscope, leaving the guide wire  36  in position for other guide wire procedures. 
     The present invention is described with reference to the embodiment shown in  FIGS. 1 to 6 . One skilled in the art would understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. Accordingly, various modifications and changes may be made to the embodiments without departing from the broadest scope of the invention as set forth in the claims that follow. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.