Patent Publication Number: US-2023132903-A1

Title: Reinforced Catheter Tip Via Roller Extrusion

Description:
PRIORITY 
     This application claims the benefit of priority to U.S. Provisional Application No. 63/275,768, filed Nov. 4, 2021, which is incorporated by reference in its entirety into this application. 
    
    
     BACKGROUND 
     Rapidly Insertable Central Catheter (RICC) systems include a catheter having a first section disposed distally, defining a single lumen, and having a first outer diameter, a second section disposed proximally, defining two or more lumen, and having a second diameter larger than the first diameter, and a transition section disposed therebetween and extending from the first outer diameter of the first section to the second outer diameter of the second section. The configuration of the RICC catheter allows a clinician to access the vasculature with the first section, dilate the access site with the transition section, and place the second section at a target location within the vasculature in a single step, mitigating the introduction and removal of multiple tools to achieve each of these steps separately. 
     Forming the RICC catheter requires coupling the three different structures of the first section, the transition section, and the second section together, while maintaining a smooth outer profile. Each of the three different structures are required to display different mechanical properties to fulfil the respective roles in the placement process. However, smaller gauge catheters provide thinner walls and as such provide a smaller surface area with which to couple the three different structures together. “Tipping” thin walled catheters can be challenging since the thin wall and small cross sectional area provides very little material with which to couple the structures together and can be susceptible to failure of the device either during manufacture or during use. Embodiments disclosed herein are directed to address the foregoing. 
     SUMMARY 
     Briefly summarized, embodiments disclosed herein are directed to distal tip structures for a catheter, such as a RICC, and associated methods of manufacture. Disclosed herein is a method of forming a catheter including, extruding a proximal section of a catheter body having a first catheter lumen and a second catheter lumen, coupling a distal tip structure to the proximal section including, placing a spiral plug in a rolled configuration within the first catheter lumen, placing a plug within the second catheter lumen, a distal tip of the plug aligned with a distal end of the second catheter lumen, aligning a lumen of the distal tip structure with the first catheter lumen, and coupling the proximal end of the distal tip structure with the distal end of the proximal section. 
     In some embodiments, the method further includes forming the spiral plug, including, providing a tube having an outer diameter equal to or greater than an inner diameter of the first catheter lumen, cutting the tube longitudinally, and rolling the tube into a spiral configuration, having an outer diameter equal to or less than the inner diameter of the first catheter lumen. In some embodiments, the spiral plug engages the first catheter lumen in an interference fit. In some embodiments, coupling the proximal end of the distal tip structure with the distal end of the proximal section includes adhering, bonding, or welding the distal tip structure with the proximal section. 
     In some embodiments, coupling the proximal end of the distal tip structure with the distal end of the proximal section includes adhering, bonding, or welding the spiral plug to an inner surface of the first catheter lumen and to one or both of the distal tip structure and the proximal section. In some embodiments, the method further includes boring out a portion of the first catheter lumen adjacent the spiral plug. In some embodiments, the distal tip structure is formed of a first material, the proximal section is formed of a second material, and the spiral plug is formed of a third material, the second material being different from one or both of the first material and the third material. 
     In some embodiments, the second material includes a more compliant, or softer durometer, mechanical properties relative to the first material. In some embodiments, the distal tip structure includes one or both of a first section and a transition section. In some embodiments, the first section defines a single lumen and defines an outer diameter that is less than an outer diameter of the proximal section. In some embodiments, the transition section defines a tapered outer profile extending from the outer diameter of the first section to the outer diameter of the proximal section. 
    
    
     
       DRAWINGS 
       A more particular description of the present disclosure will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. Example embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG.  1 A  shows a perspective view of a catheter placement system, in accordance with embodiments disclosed herein. 
         FIG.  1 B  shows a side view of a catheter of the catheter placement system of  FIG.  1 A , in accordance with embodiments disclosed herein. 
         FIG.  2    shows close up detail of a distal portion of the catheter of  FIG.  1 B , in accordance with embodiments disclosed herein. 
         FIGS.  3 - 6    show various cross-sectional views of the distal portion of  FIG.  2   , in accordance with embodiments disclosed herein. 
         FIG.  7 A  shows a distal end view of a second section of the catheter of  FIG.  1 B , in accordance with embodiments disclosed herein. 
         FIGS.  7 B- 7 D  show an exemplary method of forming a spiral plug, in accordance with embodiments disclosed herein. 
         FIG.  7 E  shows a distal end view of a second section of a catheter including a spiral plug disposed in a lumen thereof, in accordance with embodiments disclosed herein. 
         FIGS.  8 A- 8 C  show an exemplary method of coupling a distal tip structure with a second section of a catheter, in accordance with embodiments disclosed herein. 
     
    
    
     DESCRIPTION 
     Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein. 
     Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     In the following description, the terms “or” and “and/or” as used herein are to be interpreted as inclusive or meaning any one or any combination. As an example, “A, B or C” or “A, B and/or C” mean “any of the following, A, B, C, A and B, A and C, B and C, A, B and C.” An exception to this definition will occur only when a combination of elements, components, functions, steps or acts are in some way inherently mutually exclusive. 
     With respect to “proximal,” a “proximal portion” or a “proximal end portion” of, for example, a catheter disclosed herein includes a portion of the catheter intended to be near a clinician when the catheter is used on a patient. Likewise, a “proximal length” of, for example, the catheter includes a length of the catheter intended to be near the clinician when the catheter is used on the patient. A “proximal end” of, for example, the catheter includes an end of the catheter intended to be near the clinician when the catheter is used on the patient. The proximal portion, the proximal end portion, or the proximal length of the catheter can include the proximal end of the catheter; however, the proximal portion, the proximal end portion, or the proximal length of the catheter need not include the proximal end of the catheter. That is, unless context suggests otherwise, the proximal portion, the proximal end portion, or the proximal length of the catheter is not a terminal portion or terminal length of the catheter. 
     With respect to “distal,” a “distal portion” or a “distal end portion” of, for example, a catheter disclosed herein includes a portion of the catheter intended to be near or in a patient when the catheter is used on the patient. Likewise, a “distal length” of, for example, the catheter includes a length of the catheter intended to be near or in the patient when the catheter is used on the patient. A “distal end” of, for example, the catheter includes an end of the catheter intended to be near or in the patient when the catheter is used on the patient. The distal portion, the distal end portion, or the distal length of the catheter can include the distal end of the catheter; however, the distal portion, the distal end portion, or the distal length of the catheter need not include the distal end of the catheter. That is, unless context suggests otherwise, the distal portion, the distal end portion, or the distal length of the catheter is not a terminal portion or terminal length of the catheter. 
     To assist in the description of embodiments described herein, as shown in  FIG.  1 A , a longitudinal axis extends substantially parallel to an axial length of the catheter. A lateral axis extends normal to the longitudinal axis, and a transverse axis extends normal to both the longitudinal and lateral axes. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. 
       FIGS.  1 A- 1 B  show details of an exemplary catheter placement system (“placement system”)  100  generally including a needle  120 , a guidewire  130 , a syringe system  140 , and a catheter  150 . In an embodiment the catheter placement system  100  can be a Rapidly Insertable Central Catheter (RICC) placement system  100 . However, it will be appreciated that other catheter placement systems configured to place other types of catheters are also contemplated. Exemplary catheters can also include peripheral intravenous (PIV) catheters, peripherally inserted central catheter (PICC), central venous catheters (CVC), midline catheters, dialysis catheters, single lumen catheters, multi-lumen catheters, or the like. 
     In an embodiment, the catheter  150  can generally include a catheter body  152  supported at a proximal end by a catheter hub (“hub”)  160 . The hub  160  can include one or more extension legs  162  extending proximally therefrom. Each extension leg of the one or more extension legs  162  can be in fluid communication with a lumen of the catheter body  152 . The catheter body  152  can include a first section  154  disposed distally, a second section  156  disposed proximally, and a transition section  158  disposed therebetween. The first section  154  can define a single lumen and have a first outer diameter, the second section  156  can define two or more lumen and can have a second diameter larger than the first diameter. The transition section  158  disposed between the first section  154  and the second section  156  can define a tapered abluminal shape extending from the first diameter of the first section to the second diameter of the second section. A guidewire  130  can extend through a lumen of the catheter  150  from a proximal end of an extension leg  162 , to a distal tip of the first section  154 . 
     In an exemplary method of use for the catheter placement system  100  to place the catheter  150 , the needle  120  can be urged distally into the patient and access a vasculature, forming an insertion site. A syringe system  140 , or similar device can draw a fluid flow proximally through a needle lumen  122  to observe a color or pulsatile flow and confirm correct vascular access. Once correct vascular access has been confirmed, the guidewire  130  can then be advanced through the needle lumen  122  and into the vasculature to maintain patency of the insertion site. The needle  120  and syringe system  140  assembly can then be withdrawn proximally. In an embodiment, a distal tip of the guidewire  130  can reside within the needle lumen  122  during venipuncture, which can expedite accessing the vasculature once venous access is confirmed and maintain patency of the insertion site. 
     The catheter  150  can then be advanced over the guidewire  130  and into the vasculature. The first section  154  of the catheter  150 , having only a single lumen and defining a relatively smaller outer diameter, can enter the vasculature over the guidewire  130 , anchoring the insertion site. The transition section  158  can then dilate the insertion site to allow the relatively larger diameter second section  156 , defining two or more lumen, to enter the vasculature. Once the catheter  150  has been placed, the guidewire  130  can be withdrawn proximally. Further details and embodiments of RICC systems  10  can be found, for example, in U.S. Pat. No. 10,376,675, U.S. 2019/0255294, U.S. 2021/0069471, U.S. 2021/0085927, U.S. 2021/0113809, U.S. 2021/0113810, U.S. 2021/0121661, U.S. 2021/0228843, U. S. 2021/0283368, U. S. 2021/0283381, U. S. 2021/0322729, U. S. 2021/0330941, U. S. 2021/0330942, U. S. 2021/0361915, U. S. 2021/0379336, U. S. 2021/0402142, U. S. 2021/0402149, U. S. 2021/0402153, U. S. 2021/0121667, U. S. 2022/0001138, U. S. 2022/0032013, U. S. 2022/0032014, U. S. 2022/0062528, U. S. 2022/0126064, U.S. 2022/0152368, U.S. 2022/0176081, U.S. 2022/0176082, U.S. 2022/0193376, U.S. 2022/0193377, U.S. 2022/0193378, U.S. 2022/0193379, and U.S. 2022/0296862, each of which is incorporated by reference in its entirety into this application. 
     As set forth herein, different sections of the catheter  150  are required to perform different functions and as such are required to display different mechanical properties. For example, the first section  154  and/or the transition section  158  can provide a more rigid mechanical properties or harder durometer material relative to the second section  156 . As such, the first section  154  and/or transition section  158  can withstand greater axial forces without kinking or collapsing, as theses sections are urged distally forming and dilating the insertion site. The second section  156  can be formed of a softer durometer, or a more compliant material to facilitate negotiating the second section  156  through tortuous vascular pathways. Forming the catheter  150  requires the coupling together of these different structures, formed of different materials, while maintaining a smooth abluminal surface. 
       FIG.  2    shows further details of a distal portion of the catheter  150 , including the first section  154 , the second section  156 , and the transition section  158 . In an embodiment, the second section  156  can include a proximal lumen  114 A terminating at a proximal lumen aperture  116 A, and a medial lumen  114 B terminating at a medial lumen aperture  116 B. Each of the proximal lumen aperture  116 A and the medial lumen aperture  116 B can extend through a side wall of the second section  156 . Each of the proximal lumen aperture  116 A and the medial lumen aperture  116 B can be disposed proximally of the transition section  158 . In an embodiment, the proximal lumen aperture  116 A can be disposed proximally of the medial lumen aperture  116 B. In an embodiment, the proximal lumen aperture  116 A and the medial lumen aperture  116 B can be disposed equidistant from a distal tip  118  of the catheter  150 . A distal lumen  114 C of the catheter  150  can extend to a distal tip  118  of the catheter  150  and can communicate with a distal lumen aperture  116 C 
       FIG.  3    shows a cross section view of the first section  154  at point “A” of  FIG.  2   . As shown, the first section  154  can define a single lumen and a relatively smaller outer diameter.  FIG.  4    shows a cross section view of the junction between the first section  154  and the transition section  158 , at point “B” of  FIG.  2   , where a portion of the first section  154  is received within the transition section  158 .  FIG.  5    shows a cross section view of the transition section  158  at point “C” of  FIG.  2   , where an axis of the distal lumen  114 C is offset from an axis of the transition section  158  as the distal lumen  114  transitions between the first section  154  and the second section  156 .  FIG.  6    shows a cross section view of the second section  156  at point “D” of  FIG.  2   , showing the proximal lumen  114 A, the medial lumen  114 B and the distal lumen  114 C. 
     Tip Forming Methods 
       FIGS.  7 A- 8 C  show an exemplary method of manufacturing a catheter  150  including coupling a distal tip structure  170  to a second section  156  to form a catheter body  152 . In an embodiment, the distal tip structure  170  includes one or both of the transition section  158  and at least a portion of the first section  154 . In an exemplary method of coupling the distal tip structure  170  to a second section  156 , termed “tipping,” the second section  156  can be formed having one or more lumen  114 . In an embodiment, the second section  156  can be extruded and trimmed to a desired length. It will be appreciated, however, that other methods of forming the second section  156  are also contemplated. As shown in  FIGS.  7 A- 8 C , a triple lumen second section  156  is provided including a first (proximal) lumen  114 A, a second (medial) lumen  114 B, and a third (distal) lumen  114 C. However, it will be appreciated that other single or multi-lumen second sections  156 , or catheters  150 , are also contemplated. To note, the lumen  114 A,  114 B,  114 C of the catheter body  152  can be arranged radially about a central axis of the second section  156 , as shown in  FIGS.  6 - 7 A . To note,  FIGS.  8 A- 8 C  show a longitudinal cross-section of the second section  156  with the medial lumen  114 B disposed behind the proximal lumen  114 A, and the distal lumen  114 C. 
     In an embodiment, a plug  252  can be disposed into one or both of the proximal lumen  114 A and the medial lumen  114 B. For example, a first plug  252 A can be disposed within a distal end of a first lumen  114 A, and a second plug  252 B can be disposed within a distal end of a second lumen  114 B. A distal tip  254  of the plug  252  can align with a distal end  218  of the second section  156 . Optionally, a distal tip  254  of the plug  252  can be trimmed to align with a distal end  218  of the second section  156 . 
     As shown in  FIG.  7 A , with increasingly smaller gauged catheters, portions of a wall of the catheter  150  can provide a reduced thickness, e.g. thickness (T1). As such, a cross-sectional area of these thinned portions of the catheter wall can provide very little surface area for coupling a distal structure  170  thereto. As such, the joint at these areas can be weakened and potentially fail. Alternatively, the wall of the second section  156  can misalign with a wall of the distal tip structure  170  causing failure during manufacture. In an embodiment, a spiral plug  180  can be provided to facilitate coupling the distal tip structure  170  with the second section  156 . 
     As shown in  FIGS.  7 B- 7 D , the spiral plug  180  can be formed by providing a tube  182  having an outer diameter (D2) equal to or greater than an inner diameter (D1) of a lumen of the second section  156 , e.g. a distal lumen  114 C. The tube  182  can be cut longitudinally ( FIG.  7 C ) and the tube  182  can be rolled in to a spiral configuration ( FIG.  7 D ) having an outer diameter (D3) equal to or less than the inner diameter (D1) of the lumen  114 . A proximal portion of the spiral plug  180  can be placed within the lumen  114 . In an embodiment, a distal end  184  of the spiral plug  180  can extend distally of the distal end  218  of the second section  156 . In an embodiment, a distal end  184  of the spiral plug  180  can align flush with the distal end  218  of the second section  156 . Optionally, the distal end  184  of the spiral plug  180  can be trimmed to align flush with the distal end  218  of the second section  156 . 
     In an embodiment, the spiral plug  180  can be biased towards the unrolled configuration ( FIG.  7 C ). As such, when placed within the lumen  114 , the spiral plug  180  can unroll from the rolled configuration ( FIG.  7 D ) and engage the lumen  114  in an interference fit. In an embodiment, the spiral plug  180  can be coupled to an inner surface of the lumen  114  using adhesive, bonding, welding, or the like. Advantageously, the spiral plug  180  can co-operate with the wall of the second section  156  to provide a greater wall thickness (T2) to facilitate coupling a distal tip structure  170  thereto. 
       FIG.  8 A  shows a longitudinal cross-section view of the second section  156  including a first plug  252 A placed in the proximal lumen  114 A. While not shown in  FIG.  8 A , a second plug  252 B can be placed in the medial lumen  114 B, as described herein. Further, a spiral plug  180  is placed in the distal lumen  114 C. A distal tip structure  170  can then be coupled with a distal end  218  of the second section  156 , for example using adhesive, bonding, solvent bonding, welding, or the like. In an embodiment, the spiral plug  180  can facilitate aligning a lumen of the distal tip structure  170  with a lumen  114  of the second section  156  to form the distal lumen  114 C extending to a distal lumen aperture  116 C. 
     In an embodiment, a first plug  252 A can seal the proximal lumen  114 A, and the second plug  252 B can seal the medial lumen  114 B, proximally of the transition section  158 . The proximal lumen aperture  116 A can then be formed through a wall of the catheter body  152  and communicate with the proximal lumen  114 A. The medial lumen aperture  116 B can then be formed through a wall of the catheter body  152  and communicate with the medial lumen  116 B. 
     In an embodiment, the spiral plug  180  can then be removed from the lumen  114  once the distal tip structure  170  is coupled to the second section  156 . In an embodiment, the spiral plug  180  can be formed of a sacrificial material. During the tipping of the second section  156  with the distal structure  170 , a portion of the spiral plug  180  can be melted and fused with an inner wall of the lumen  114  across the join between the second section  156  and the distal structure  170 . As such, the spiral plug  180  can provide additional support across the join, ensuring a secure coupling. As shown in  FIG.  8 C , the bore of the spiral plug  180  can then be widened once the distal tip structure  170  has been coupled with the second section  156 . 
     In an embodiment, one or both of the first section  154  and the transition section  158 , i.e. the distal tip structure  170  can be formed of a first material, and the second section  156  can be formed of a second material. In an embodiment, the first material can display different mechanical properties from the second material. In an embodiment, one of the first material or the second material can be a plastic, polymer, polyurethane, composite, elastomer, or the like. In an embodiment, the first material can display more rigid, or harder durometer, mechanical properties relative to the second material that can display more compliant or softer durometer mechanical properties. 
     In an embodiment, the spiral plug  180  can be formed of the same material as one of a first material of the distal tip structure  170  or a second material of the second section  156 . In an embodiment, the spiral plug  180  can be formed from a third material that can be different from both of the first material and the second material. In an embodiment, the third material can be a plastic, polymer, elastomer, polyurethane combinations thereof, or the like. 
     In an embodiment, the distal tip structure  170  can be coupled with the second section  156  by placing one or more of the distal end  218  of the second section  156 , a plug  252 , a spiral plug  180 , and the distal tip structure  170  within a mold or die. Optionally a mandrel (not shown) can be placed within a portion of the distal lumen  114 C. Energy (thermal, RF, ultrasonic welding, or the like) and/or pressure can be applied to the assembly within the die to melt or fuse the material of the distal end  218  of the second section  156 , the plug  252 , the spiral plug  180 , and/or the distal tip structure  170  together to form the catheter body  152  of the catheter  150 . The mandrel can define a portion of the distal lumen  114 C extending therethrough and can be removed after the catheter body  152  has been formed. 
     In an embodiment, the distal tip structure  170  can define one or both of the transition section  158  and the first section  154 . In an embodiment, the distal tip structure  170  can include the transition section  158  and can define a recess configured to receive a proximal end of the first section  154 . The proximal end of the first section  154  can then be coupled with the transition section  158  using adhesive, bonding, welding, or the like. As such, the first section  154  can be formed of the third material, or of a fourth material different from that of the first, second, and third material. 
     While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.