Patent Publication Number: US-2009234227-A1

Title: Ribbed Catheter

Description:
TECHNICAL FIELD 
     The technical field of this disclosure is medical devices, particularly, a catheter. 
     BACKGROUND 
     Catheters are used in a number of medical procedures to deliver medical devices to a target site within a body and other purposes. Catheters, typically, define an inner lumen with an inner wall of the catheter, and this inner lumen can surround dedicated lumens for a number of purposes, such as delivering contrast fluids, delivering devices, or the like. However, with increasing number of dedicated lumens within the catheter, the profile of the catheter increases to accommodate the size of the dedicated lumens. 
     However, physicians frequently prefer smaller profiles, resulting in a desire to reduce the number of dedicated lumens within the catheter. Frequently, this desire results in catheters failing to include a lumen dedicated to delivering contrast. 
     It would be desirable to overcome the above disadvantages. 
     SUMMARY OF THE INVENTION 
     One aspect according to the present invention provides a catheter that includes a length sufficient to extend from an entry point into a body to a target site within the body and a substantially circular inner wall defining an inner lumen. The catheter further includes an outer wall separated from and opposing the inner wall, and at least a first rib and a second rib extending from the outer wall. The first rib and second rib define a first fluid flow channel extending along the outer wall. 
     Another aspect provides a vascular treatment system that includes an introducer sheath and a catheter disposed within the introducer sheath. The catheter includes a length sufficient to extend from an entry point into a body to a target site within the body and a substantially circular inner wall defining an inner lumen. The catheter further includes an outer wall opposing and separated from the inner wall, and at least a first rib and a second rib extending from the outer wall, wherein the first rib and second rib define a first fluid flow channel extending along the outer wall, and wherein the first fluid flow channel extends substantially the length, wherein the first rib and second rib each include a contact surface in frictional contact with an inner surface of the introducer sheath or guide catheter. 
     Another aspect provides a method of obtaining fluoroscopic images during a medical procedure. The method includes inserting a catheter into a vasculature of a patient, the catheter including a length, and the catheter further including at least one fluid flow channel. The method further includes injecting at least one contrast substance into the fluid flow channel and obtaining a fluoroscopic image of the body lumen surrounding the discharge site of the contrast from the catheter during a medical procedure based on the injection. 
     The foregoing and other features and advantages will become further apparent from the following detailed description, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view of a catheter; 
         FIG. 2  is a cross sectional view of a catheter; 
         FIG. 3  is a flowchart of a method of obtaining fluoroscopic images during a medical procedure; 
         FIGS. 4-9  illustrate embodiments of catheter delivery systems; 
         FIG. 10A  is an oblique view of a linear section of one embodiment of the catheter and; 
         FIGS. 10-13  provide schematic representations illustrating several embodiments of catheters with multiple fluid flow channels, such a the one pictured in  FIG. 10A . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments will now be described by reference to the figures wherein like numbers refer to like structures. The terms “distal” and “proximal” are used herein with reference to the treating clinician during the use of the catheter system: “distal” indicates an apparatus portion distant from, or a direction away from the clinician and “proximal” indicates an apparatus portion near to, or a direction towards the clinician. 
       FIG. 1  illustrates one embodiment of a catheter  100 , in cross section A-A ( FIG. 4 ). Catheter  100  includes an inner wall  110  that defines inner lumen  115 . Any number of devices may be carried, limited only by size of such device and the size of inner lumen  115 , within inner lumen  115 . In one embodiment, inner wall  110  is substantially circular. In other embodiments, inner wall  110  can be a substantially non-circular tubular shape such as ovoid. Additionally, catheter  100  includes an outer wall  120 . Outer wall  120  opposes inner wall  110 , and is separated from the inner wall  110  by a wall thickness, d, of the catheter. While not shown in cross sectional  FIG. 1 , but as seen in  FIG. 4 , catheter  100  includes a length sufficient to extend from an entry point into a body to a target site within the body. In one embodiment, catheter  100  is a vascular catheter. In other embodiments, catheter  100  is another catheter, such as a urethral catheter, Foley catheter or the like. In one embodiment, catheter  100  serves as a delivery device for a stent (not shown), including drug coated stents. Additionally, catheter  100  includes at least a first rib  130  and a second rib  140  extending radially from the outer wall. The first rib  130  and second rib  140  define a first fluid flow channel  150  extending along the outer wall  120  between the ribs and any element that would span the gap between the top of the ribs. The first fluid flow channel  150  extends substantially the length of catheter  100 . Any number of ribs can be included, limited only by the circumference of the catheter and the circumferential thickness of the individual ribs. 
     The outer surface of first rib  130  and second rib  140  may contact any introducer sheath or guide catheter used in the procedure, and may be near a body lumen wall, such as a vessel wall or urethral wall. Because of such possible contact, the outer surfaces are preferably rounded with few angles (sharp corners). The fluid flow channel  150  extends substantially the entire length of the catheter  100 , providing a fluid flow channel for receiving the injection of contrast media during the procedure, but without a dedicated intra-catheter carrying tube. Although illustrated with substantially perpendicular angles, in implementation most surfaces will be radiused. 
       FIG. 2  illustrates another embodiment of a catheter  200  that includes an inner wall  210  that defines inner lumen  215 . Any number of devices may be carried within inner lumen  215 , limited only by size of such device and the size of inner lumen  215 . In one embodiment, inner wall  210  is substantially circular. In other embodiments, inner wall  210  is substantially ovoid. Additionally, catheter  200  includes an outer wall  220 . Outer wall  220  opposes inner wall  210 , and is separated from the inner wall  210  by a thickness, d, of the catheter. While not shown in cross sectional  FIG. 2 , catheter  200  has a length sufficient to extend from an entry point into a body to a target site within the body. In one embodiment, catheter  200  is a vascular catheter. In other embodiments, catheter  200  is any other catheter, such as a urethral catheter, Foley catheter or the like. Additionally, catheter  200  includes at least a first rib  230  and a second rib  240  extending radially from the outer wall. The first rib  230  and second rib  240  define a first fluid flow channel  250  extending along the outer wall  220 . The first fluid flow channel  250  extends substantially the length of catheter  200 . Additionally, catheter  200  includes a middle member  260  disposed within the lumen  215   
     Catheter  100  and catheter  200  can be designed for a particular application. In one embodiment, the first fluid flow channel is substantially axial. In such embodiments, the axial fluid flow channel runs substantially the entire length of the catheter while reducing any radial portion of the fluid flow channel. Once contrast is injected into the fluid flow channels, the longitudinal or axial fluid flow channels will appear bright fluroscopically. Other embodiments of catheters of  FIG. 1  and/or  FIG. 2 , respectively,  100  and/or  200  include a fluid flow channel that extends axially and radially in a helical pattern along the length of the catheter. Such embodiments will provide a ‘corkscrew’ view during a procedure when fluoroscopic images are taken, when the contrast fluid has been introduced into the fluid flow channels. 
     Multiple fluid flow channels are included in various embodiments, such that the catheter includes at least a third rib to define a second fluid flow channel, such as between the third rib and the first rib, or the third rib and the second rib. Any number of ribs may be provided, limited only by the thickness of the ribs, and the outer diameter of the catheter.  FIG. 10A  is an oblique view of a section of the catheter shaft for example of  FIG. 1 .  FIGS. 10-13  provide a schematic illustration of partial side views of different embodiments of catheters with multiple fluid flow channels. The schematic illustration of  FIG. 10  correlates to the catheter shaft section shown in  FIG. 10A . The other schematic illustrations presented should be assumed to provide a similar correlation to other possible fluid flow channel configurations similar to that shown in  FIG. 10A  as will be apparent to those skilled in the art. For example, the fluid flow channels may be substantially parallel (as in  FIG. 10 ) or not substantially parallel (as in  FIG. 11 ). In one embodiment, a first fluid flow channel and a second fluid flow channel intersect such that the first fluid flow channel and second fluid flow channel are in fluidic communication via at least one intersection (as in  FIG. 12 ). In one embodiment, a first intersection and a second intersection are separated by a known distance, such as 6 inches, such that the catheter can function similar to a measuring stick, when imaged fluoroscopically. In one such embodiment, the first fluid flow channel and second fluid flow channel are substantially parallel for a first portion of the length of the catheter and substantially non-parallel for a second portion of the length of the catheter ( FIGS. 11 and 13 ). In yet other embodiments, the fluid flow channels have a substantially consistent width ( FIG. 10 ). In yet other embodiments, the fluid flow channels do not have a substantially consistent width ( FIG. 13 ), and in one such embodiment, the fluid flow channel changes widths at a known separation such that the catheter can function as a measure of distance when imaged fluoroscopically during a procedure. In yet other embodiments, a portion of at least one rib is removed, or has a lower height than elsewhere along the rib, at predetermined distances providing fluidic communication between adjoining fluid flow channels. 
     Additionally, the height of the ribs may be varied depending on the target site and the diameter of any vasculature or other body vessel to be traversed during the procedure to reduce any discrepancy between the French size of the catheter measured at the outer surface of the ribs and the diameter of the vessel or body lumen to be traversed. In one such embodiment, the first fluid flow channel includes a first marked portion and a second marked portion, and wherein the first marked portion and second marked portion are offset by a predetermined axial distance. 
       FIG. 3  illustrates one embodiment of a method  300  for obtaining fluoroscopic images during a medical procedure. Method  300  begins at step  310  by inserting a catheter into a vasculature of a patient, the catheter including a length, and the catheter further including at least one fluid flow channel extending substantially the entire length along an outer wall of the catheter. Any appropriate technique for catheter insertion can be, depending on the type of catheter as well as the destination. For example, a urethral catheter is inserted using appropriate urethral insertion techniques, while vascular catheters are inserted using appropriate vascular catheter insertion techniques. During the procedure, at least one contrast substance is injected into at least one fluid flow channel at step  320 . The contrast substance may be a contrast dye, or any other substance used to provide improved fluorographic imaging during medical procedures. The contrast substance is housed in a, generally, fluid reservoir disposed outside of the patient&#39;s body, and the contrast substance is injected into the fluid flow reservoir, such as with a needle and blocking element (not shown—which prevents backflow of the contrast) placed into fluid communication with the fluid flow reservoir. 
     At step  330 , method  300  obtains fluoroscopic image of the vasculature during a medical procedure based on the injection. Any appropriate fluoroscopy technique can be used. Based on the image, the medial professional undertaking the procedure continues the procedure. 
       FIG. 4  illustrates a top view of a stent delivery system  400 . Stent delivery system  400  is a self expanding stent delivery system without a stability member. Stent delivery system  400  includes a luer fitting  405  at the proximal end of stent delivery system  400  and a tip  408  at the distal end. Handle  415  provides means for gripping and controlling the stent delivery system during a procedure. Additionally, stent delivery system  400  includes a strain relief device  420  at a proximal end of the catheter  450 . Catheter  450  is implemented as catheter  100  or catheter  200  and includes at least a first fluid flow channel extending substantially the entire length of the catheter. 
       FIG. 5  illustrates a top view of a stent delivery system  500 . As illustrated, stent delivery system  500  is a self expanding stent delivery system without a stability member, and with an introducer sheath. Stent delivery system  500  includes a luer fitting  505  at the proximal end of stent delivery system  500  and a tip  508  at the distal end. Handle  515  provides means for gripping and controlling the stent delivery system during a procedure. Additionally, stent delivery system  500  includes a strain relief device  520  at a proximal end of the catheter  550 . Catheter  550  is implemented as catheter  100  or catheter  200  and includes at least a first fluid flow channel extending substantially the entire length of the catheter. Additionally, introducer sheath  580  assists in introduction of the catheter  500  into the body lumen. 
       FIG. 6  illustrates a top view of a stent delivery system  600 . As illustrated, stent delivery system  600  is a self expanding stent delivery system with a ribbed stability member. In  FIG. 6 , the stability member  670  includes the fluid flow channels, as outlined with reference to catheter  100  or catheter  200 , instead of the catheter  690 . Stent delivery system  600  includes a luer fitting  605  at the proximal end of stent delivery system  600  and a tip  608  at the distal end. Handle  615  provides means for gripping and controlling the stent delivery system during a procedure. Additionally, stent delivery system  600  includes a strain relief device  620  at a proximal end of the catheter  650 . Catheter  650  is implemented as any catheter known in the art. 
       FIG. 7  illustrates a top view of a stent delivery system  700 . As illustrated, stent delivery system  700  is a self expanding stent delivery system with a ribbed stability member. In  FIG. 7 , the stability member  770  includes the fluid flow channels, as outlined with reference to catheter  100  or catheter  200 , instead of the catheter  750 . Stent delivery system  700  includes a luer fitting  705  at the proximal end of stent delivery system  700  and a tip  708  at the distal end. Handle  715  provides means for gripping and controlling the stent delivery system during a procedure. Additionally, stent delivery system  700  includes a strain relief device  720  at a proximal end of the catheter  750 . Catheter  750  is implemented as any catheter known in the art. Additionally, introducer sheath  780  assists in introduction of the catheter  750  into the body lumen. Contrast is injected through the introducer sheath and moves into the vasculature or other vessel through the clearance between the outer diameter of the catheter and inner diameter of the introducer sheath. Backward flow is blocked by the hemostasis valve of the introducer. This results in contrast flow in the space between the catheter and introducer sheath/guide catheter. 
       FIG. 8  illustrates a top view of a stent delivery system  800 . As illustrated, stent delivery system  800  is a balloon expandable stent delivery system without a stability member. Stent delivery system  800  includes a luer fitting  805  at the proximal end of stent delivery system  800  and a tip  808  at the distal end. Catheter  850  is implemented as catheter  100  or catheter  200  and includes at least a first fluid flow channel extending substantially the entire length of the catheter. Furthermore,  FIG. 8  illustrates a stent  801  disposed proximal tip  808  surrounding a balloon (not shown) for stent expansion at a target site. 
       FIG. 9  illustrates a top view of a stent delivery system  900 . As illustrated, stent delivery system  900  is a self expanding stent delivery system without a stability member, and with an introducer sheath. Stent delivery system  900  includes a luer fitting  905  at the proximal end of stent delivery system  900  and a tip  908  at the distal end. Catheter  950  is implemented as catheter  100  or catheter  200  and includes at least a first fluid flow channel extending substantially the entire length of the catheter. Additionally, introducer sheath  980  assists in introduction of the catheter  950  into the body lumen. Furthermore,  FIG. 9  illustrates a stent  901  disposed proximal with, and near, tip  908  surrounding a balloon (not shown) for stent expansion at a target site. 
     Those of skill in the art will recognize that the teachings herein provide for a catheter that provides enhanced means of contrast injection for increased fluoroscopic imaging characteristics of the vasculature, but without a dedicated inner lumen for contrast injection. The fluid flow channels can further be used for estimating internal distances with relative ease during a procedure. By eliminating the need for an internal lumen, the effective French size of the overall catheter is reduced, improving its handling within the body. The catheters disclosed herein are made of any appropriate material, such as the materials generally used to manufacture catheters. Such materials are preferably biocompatible, with sufficient softness as to reduce trauma to the vessel walls and sufficient rigidity as to navigate the vessels. 
     While specific embodiments are disclosed herein, various changes and modifications can be made without departing from the spirit and scope of the invention.