Reinforced catheter tip by roller extrusion

Abstract

In smaller gauge catheters, forming the distal tip structure, referred to as "tipping," can be much more difficult. The thin wall thickness of these smaller gauge catheters provides a smaller cross-sectional area for mating the distal tip structure. This increases the risk of the device failing during manufacture or use. To address the above challenges, embodiments include forming and disposing a helical plug within the lumen of the proximal portion of the catheter. The helical plug cooperates with the catheter to provide an increased wall thickness and cross-sectional area for mating the distal tip structure. The helical plug can also align the lumen of the catheter body with the lumen of the distal tip structure. The helical plug can be sacrificed to provide more material across the junction, reducing junction failure.

Description

[Technical field]

[0001] The present invention relates to a roller extruded reinforced catheter tip. [Background technology]

[0002] A rapid insertion central catheter (RICC) system includes a catheter having a distal first section having a first outer diameter defining a single lumen, a proximal second section having a second diameter greater than the first diameter defining two or more lumens, and a transition section between the first and second sections and extending from the first outer diameter of the first section to the second outer diameter of the second section. The RICC catheter is designed to allow 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, eliminating the need to insert and remove multiple instruments to perform each of these steps individually.

[0003] Forming a RICC catheter requires maintaining a smooth profile while joining three distinct structures: a first section, a transition section, and a second section. Each of these three distinct structures requires different mechanical properties to perform their role during the deployment process. However, smaller gauge catheters have thinner walls and therefore less surface area to join the three distinct structures. "Tipping" a thin-walled catheter can be difficult because the thin walls and small cross-sectional area provide very little material to join the structures, and can lead to device failure during manufacture and use. The embodiments disclosed herein are directed to addressing the aforementioned challenges. Summary of the Invention

[0004] Briefly summarized, embodiments disclosed herein relate to distal tip structures for catheters, such as RICCs, and associated methods of manufacture. Disclosed herein is a method of forming a catheter that includes extruding a proximal section of a catheter body having a first catheter lumen and a second catheter lumen, and bonding a distal tip structure to the proximal section, the bonding comprising placing a helical plug in a rolled configuration within the first catheter lumen, placing the plug within the second catheter lumen, where the distal tip of the plug is aligned with a distal end of the second catheter lumen, aligning the lumen of the distal tip structure with the first catheter lumen, and bonding the proximal end of the distal tip structure to the distal end of the proximal section.

[0005] In some embodiments, the method further includes forming a helical plug, where forming the helical plug includes providing a tube having an outer diameter equal to or greater than the inner diameter of the first catheter lumen, cutting the tube longitudinally, and winding the tube into a helical shape having an outer diameter equal to or less than the inner diameter of the first catheter lumen. In some embodiments, the helical plug engages the first catheter lumen with an interference fit. In some embodiments, coupling the proximal end of the distal tip structure to the distal end of the proximal portion includes bonding, joining, or welding the distal tip structure to the proximal portion.

[0006] In some embodiments, coupling the proximal end of the distal tip structure to the distal end of the proximal section includes adhering, bonding or welding a helical 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 drilling a portion of the first catheter lumen adjacent the helical plug. In some embodiments, the distal tip structure is formed from a first material, the proximal section is formed from a second material, and the helical plug is formed from a third material, the second material being different from one or both of the first and third materials.

[0007] In some embodiments, the second material has softer, i.e., softer, durometer mechanical properties relative to the first material. In some embodiments, the distal tip structure includes one or both of a first portion and a transition portion. In some embodiments, the first portion defines a single lumen and defines an outer diameter that is smaller than an outer diameter of the proximal portion. In some embodiments, the transition portion defines a tapered profile extending from the outer diameter of the first portion to the outer diameter of the proximal portion.

[0008] A more particular description of the present disclosure will be provided by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. These drawings depict only typical embodiments of the invention and therefore should not be considered as limiting its scope. Exemplary embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings. [Brief description of the drawings]

[0009] [Figure 1A] 1 shows a perspective view of a catheter placement system according to an embodiment disclosed herein. [Figure 1B] FIG. 1B shows a side view of a catheter of the catheter placement system of FIG. 1A in an embodiment disclosed herein. [Diagram 2] FIG. 1C shows an enlarged detail of a distal portion of the catheter of FIG. 1B according to an embodiment disclosed herein. [Diagram 3] 3A-3D show various cross-sectional views of the distal portion of FIG. 2 in accordance with an embodiment disclosed herein. [Figure 4] 3A-3D show various cross-sectional views of the distal portion of FIG. 2 in accordance with an embodiment disclosed herein. [Diagram 5] 3A-3D show various cross-sectional views of the distal portion of FIG. 2 in accordance with an embodiment disclosed herein. [Figure 6] 3A-3D show various cross-sectional views of the distal portion of FIG. 2 in accordance with an embodiment disclosed herein. [Figure 7A]FIG. 1C shows a distal end view of a second portion of the catheter of FIG. 1B in an embodiment disclosed herein. [Figure 7B] 1 illustrates an exemplary method for forming a helical plug in accordance with embodiments disclosed herein. [Figure 7C] 1 illustrates an exemplary method for forming a helical plug in accordance with embodiments disclosed herein. [Figure 7D] 1 illustrates an exemplary method for forming a helical plug in accordance with embodiments disclosed herein. [Figure 7E] 1 illustrates an exemplary method for forming a helical plug in accordance with embodiments disclosed herein. [Figure 8A] 1 illustrates an exemplary method of coupling a distal tip structure to a second portion of a catheter in accordance with embodiments disclosed herein. [Figure 8B] 1 illustrates an exemplary method of coupling a distal tip structure to a second portion of a catheter in accordance with embodiments disclosed herein. [Figure 8C] 1 illustrates an exemplary method of coupling a distal tip structure to a second portion of a catheter in accordance with embodiments disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Before disclosing some specific embodiments in more detail, it should be understood that the specific embodiments disclosed herein are not intended to limit the scope of the concepts provided herein. It should also be understood that a specific embodiment disclosed herein may have features that are easily separable from the specific embodiment and that may be combined or substituted in any way with features of any of the numerous other embodiments disclosed herein.

[0011] With regard to the terms used herein, it should also be understood that these terms are intended to describe certain embodiments and are not intended to 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 within a group of features or steps and do not provide sequential or numerical limitations. For example, the "first", "second", and "third" features or steps do not necessarily have to appear in that order, and a particular embodiment including such features or steps is not necessarily limited to three features or steps. Designations such as "left", "right", "up", "down", "front", "rear", etc. are used for convenience and do not imply, for example, a specific fixed position, orientation, or direction. Instead, such designations are used to reflect, for example, a relative position, orientation, or direction. The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0012] In the following description, the terms "or" and "and / or" as used herein should be interpreted to include or mean any one or any combination. For example, "A, B, or C" or "A, B, and / or C" means "any of A, B, C, A and B, A and C, B and C, A, B and C." Exceptions to this definition occur only when elements, components, features, steps or actions are in some way inherently mutually exclusive.

[0013] With respect to "proximal," for example, the "proximal portion" or "proximal end portion" of a catheter disclosed herein includes the portion of the catheter intended to be near the clinician when the catheter is used on a patient. Similarly, for example, the "proximal length" of a catheter includes the length of the catheter intended to be near the clinician when the catheter is used on a patient. For example, the "proximal end" of a catheter includes the end of the catheter intended to be near the clinician when the catheter is used on a patient. The proximal portion, proximal end portion, or proximal length of a catheter can include the proximal end of the catheter. However, the proximal portion, proximal end portion, or proximal length of a catheter need not include the proximal end of the catheter. That is, unless the context suggests otherwise, the proximal portion, proximal end portion, or proximal length of a catheter is not the terminal portion or terminal length of the catheter.

[0014] With respect to "distal," for example, a "distal portion" or "distal end portion" of a catheter disclosed herein includes a portion of the catheter intended to be near or within a patient when the catheter is used with a patient. Similarly, for example, a "distal length" of a catheter includes a length of the catheter intended to be near or within a patient when the catheter is used with a patient. For example, a "distal end" of a catheter includes an end of the catheter intended to be near or within a patient when the catheter is used with a patient. A distal portion, end portion, or length of a catheter can include the distal end of the catheter. However, a distal portion, end portion, or length of a catheter need not include the distal end of the catheter. That is, unless the context suggests otherwise, a distal portion, end portion, or length of a catheter is not a terminal portion or length of the catheter.

[0015] To aid in illustrating the embodiments disclosed herein, as shown in Figure 1A, the longitudinal axis extends generally parallel to the axial length of the catheter, the transverse axis extends perpendicular to the longitudinal axis, and the transverse axis extends perpendicular to both the longitudinal and transverse axes.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. 1A-1B show details of an exemplary catheter placement system ("placement system") 100, which generally includes a needle 120, a guidewire 130, a syringe system 140, and a catheter 150. In one embodiment, the catheter placement system 100 may be a rapid-insertion central venous catheter placement system 100. However, other catheter placement systems configured to place other types of catheters are contemplated. Exemplary catheters may also include peripheral intravenous (PIV) catheters, peripherally inserted central catheters (PICCs), central venous catheters (CVCs), midline catheters, dialysis catheters, single lumen catheters, multi-lumen catheters, and the like.

[0017] In one embodiment, the catheter 150 may generally include a catheter body 152 supported at a proximal end by a catheter hub ("hub") 160. The hub 160 may include one or more extension legs 162 extending proximally. Each of the one or more extension legs 162 may be in fluid communication with a lumen of the catheter body 152. The catheter body 152 may include a distally located first portion 154, a proximally located second portion 156, and a transition portion 158 located between the two portions. The first portion 154 may define a single lumen and may have a first outer diameter. The second portion 156 may define two or more lumens and may have a second diameter that is greater than the first diameter. The transition portion 158 located between the first portion 154 and the second portion 156 may define a tapered abluminal shape extending from a first diameter of the first portion to a second diameter of the second portion. The guidewire 130 may extend from the proximal end of the extension leg 162 through the lumen of the catheter 150 to the distal tip of the first portion 154 .

[0018] In an exemplary method of using the catheter placement system 100 to place a catheter 150, the needle 120 can be pushed distally into the patient's body and the vasculature can be accessed to create an insertion site. The syringe system 140, or a similar device, can draw fluid flow proximally through the needle lumen 122 to observe color and pulsatile flow and to confirm proper vasculature access. Once successful vasculature access is confirmed, the guidewire 130 can 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 one embodiment, the distal tip of the guidewire 130 can remain in the needle lumen 122 during venipuncture, which can facilitate access to the vasculature and maintain patency of the insertion site once venous access is confirmed.

[0019] Catheter 150 may then be advanced over guidewire 130 into the vasculature. A first section 154 of catheter 150, having a single lumen and a relatively small outer diameter, may enter the vasculature over guidewire 130 to secure the insertion site, and a transition section 158 may expand the insertion site to allow a larger diameter second section 156, defining two or more lumens, to enter the vasculature. Once catheter 150 is in place, guidewire 130 may be withdrawn proximally.Further details and embodiments of the RICC system 10 may be found in, for example, U.S. Pat. No. 10,376,675, U.S. Patent Application Publication No. 2019 / 0255294, U.S. Patent Application Publication No. 2021 / 0069471, U.S. Patent Application Publication No. 2021 / 0085927, U.S. Patent Application Publication No. 2021 / 0113809, U.S. Patent Application Publication No. 2021 / 0113810, U.S. Patent Application Publication No. 2021 / 0121661, U.S. Patent Application Publication No. 2021 / 0228 843, U.S. Patent Application Publication No. 2021 / 0283368, U.S. Patent Application Publication No. 2021 / 0283381, U.S. Patent Application Publication No. 2021 / 0322729, U.S. Patent Application Publication No. 2021 / 0330941, U.S. Patent Application Publication No. 2021 / 0330942, U.S. Patent Application Publication No. 2021 / 0361915, U.S. Patent Application Publication No. 2021 / 0379336, U.S. Patent Application Publication No. 2021 / 0402142, U.S. Patent Application Publication No. No. 2021 / 0402149, U.S. Patent Application Publication No. 2021 / 0402153, U.S. Patent Application Publication No. 2021 / 0121667, U.S. Patent Application Publication No. 2022 / 0001138, U.S. Patent Application Publication No. 2022 / 0032013, U.S. Patent Application Publication No. 2022 / 0032014, U.S. Patent Application Publication No. 2022 / 0062528, U.S. Patent Application Publication No. 2022 / 0126064, U.S. Patent Application Publication No. 2022 / 0152368 No. 2022 / 0176081, U.S. Patent Application Publication No. 2022 / 0176082, U.S. Patent Application Publication No. 2022 / 0193376, U.S. Patent Application Publication No. 2022 / 0193377, U.S. Patent Application Publication No. 2022 / 0193378, U.S. Patent Application Publication No. 2022 / 0193379, and U.S. Patent Application Publication No. 2022 / 0296862, each of which is incorporated by reference in its entirety into this application.

[0020] As described herein, different portions of the catheter 150 are required to perform different functions and therefore exhibit different mechanical properties. For example, the first portion 154 and / or the transition portion 158 may have stiffer mechanical properties or a harder durometer material than the second portion 156. Thus, the first portion 154 and / or the transition portion 158 may be able to withstand greater axial forces without kinking or collapsing as they are pushed distally to form and expand the insertion site. To facilitate navigating tortuous vascular pathways, the second portion 156 may be formed of a softer durometer material or a more flexible material. Formation of the catheter 150 requires bonding together these different structures formed of different materials while maintaining a smooth abluminal surface.

[0021] FIG. 2 shows further details of the distal portion of the catheter 150, including the first portion 154, the second portion 156, and the transition portion 158. In one embodiment, the second portion 156 can include a proximal lumen 114A terminating at a proximal lumen opening 116A and an intermediate lumen 114B terminating at an intermediate lumen opening 116B. Each of the proximal lumen opening 116A and the intermediate lumen opening 116B can extend through a sidewall of the second portion 156. Each of the proximal lumen opening 116A and the intermediate lumen opening 116B can be disposed proximal to the transition portion 158. In one embodiment, the proximal lumen opening 116A can be disposed proximal to the intermediate lumen opening 116B. In one embodiment, the proximal lumen opening 116A and the intermediate lumen opening 116B can be disposed equidistant from the distal tip 118 of the catheter 150. The distal lumen 114C of the catheter 150 may extend to a distal tip 118 of the catheter 150 and may communicate with a distal lumen opening 116C.

[0022] FIG. 3 illustrates a cross-sectional view of the first portion 154 at the location indicated by "A" in FIG. 2. As shown, the first portion 154 may define a single lumen and a relatively small outer diameter. FIG. 4 illustrates a cross-sectional view of the junction between the first portion 154 and the transition portion 158 at the location indicated by "B" in FIG. 2. FIG. 5 illustrates a cross-sectional view of the transition portion 158 at the location indicated by "C" in FIG. 2, where the axis of the distal lumen 114C is offset from the axis of the transition portion 158 as the distal lumen 114 transitions between the first portion 154 and the second portion 156. FIG. 6 illustrates a cross-sectional view of the second portion 156 at the location indicated by "D" in FIG. 2, and shows the proximal lumen 114A, the intermediate lumen 114B, and the distal lumen 114C.

[0023] Tip formation method 7A-8C illustrate an exemplary method of manufacturing the catheter 150, including joining the distal tip structure 170 to the second section 156 to form the catheter body 152. In one embodiment, the distal tip structure 170 includes one or both of a transition section 158 and at least a portion of the first section 154. In an exemplary method of joining the distal tip structure 170 to the second section 156, referred to as "tipping," the second section 156 may be formed to have one or more lumens 114. In one embodiment, the second section 156 may be extruded and trimmed to a desired length. However, other methods of forming the second section 156 are contemplated. As shown in FIGS. 7A-8C, a second section 156 is provided having three lumens, including a first (proximal) lumen 114A, a second (middle) lumen 114B, and a third (distal) lumen 114C. However, other single or multi-lumen types of second section 156 or catheter 150 are also contemplated. Note that the lumens 114A, 114B, 114C of the catheter body 152 may be radially disposed about a central axis of the second section 156, as shown in Figures 6-7A. Note that Figures 8A-8C show a longitudinal cross section of the second section 156, with the intermediate lumen 114B disposed posterior to the proximal lumen 114A, and the distal lumen 114C.

[0024] In one embodiment, plug 252 may be disposed in one or both of proximal lumen 114A and intermediate lumen 114B. For example, a first plug 252A may be disposed in a distal end of first lumen 114A and a second plug 252B may be located in a distal end of second lumen 114B. A distal tip 254 of plug 252 may be aligned with a distal end of second portion 156. Optionally, distal tip 254 of plug 252 may be trimmed to align with distal end 218 of second portion 156.

[0025] As shown in FIG. 7A, smaller gauge catheters may have portions of the walls of the catheter 150 with a reduced thickness, e.g., thickness (T1). Thus, the cross-sectional area of ​​these thinner portions of the catheter wall may provide very little surface area for coupling with the distal structure 170. Thus, the bond in these regions may be weakened and potentially fail. Alternatively, the walls of the second portion 156 may not match the walls of the distal tip structure 170, resulting in manufacturing defects. In one embodiment, a helical plug 180 may be provided to facilitate coupling between the distal tip structure 170 and the second portion 156.

[0026] As shown in FIGS. 7B-7D, the helical plug 180 can be formed by providing a tube 182 having an outer diameter (D2) equal to or greater than the inner diameter (D1) of a lumen of the second portion 156, e.g., distal lumen 114C. The tube 182 can be cut longitudinally (FIG. 7C), and the tube 182 can be wound into a helical shape (FIG. 7D) having an outer diameter (D3) equal to or less than the inner diameter (D1) of the lumen 114. A proximal portion of the helical plug 180 can be disposed within the lumen 114. In one embodiment, the distal end 184 of the helical plug 180 can extend distal to the distal end 218 of the second portion 156. In one embodiment, the distal end 184 of the helical plug 180 can be aligned flush with the distal end 218 of the second portion 156. Optionally, the distal end 184 of the helical plug 180 may be trimmed to be flush with the distal end 218 of the second portion 156 .

[0027] In one embodiment, the helical plug 180 can be biased toward the unrolled configuration (FIG. 7C). Thus, when positioned within the lumen 114, the helical plug 180 can unfold from the rolled configuration and engage the lumen 114 with an interference fit. In one embodiment, the helical plug 180 can be coupled to the inner surface of the lumen 114 using an adhesive, bonding, welding, or the like. Advantageously, the helical plug 180 can cooperate with the wall of the second portion 156 to provide a greater wall thickness (T2) to facilitate coupling of the distal tip structure 170.

[0028] 8A illustrates a longitudinal cross-sectional view of the second portion 156 including a first plug 252A disposed in the proximal lumen 114A. Although not shown in FIG. 8A, a second plug 252B can be disposed in the intermediate lumen 114B, as described herein. Additionally, a helical plug 180 can be disposed in the distal lumen 114C. The distal tip structure 170 can then be coupled to the distal end 218 of the second portion 156, such as with an adhesive, bonding, solvent bonding, or welding. In one embodiment, the helical plug 180 can facilitate aligning the lumen of the distal tip structure 170 with the lumen 114 of the second portion 156 to form a distal lumen 114C that extends to the distal lumen opening 116C.

[0029] In one embodiment, a first plug 252A can seal the proximal lumen 114A and a second plug 252B can seal the intermediate lumen 114B proximal to the transition section 158. A proximal lumen opening 116A can then be formed through the wall of the catheter body 152 to communicate with the proximal lumen 114A. Additionally, an intermediate lumen opening 116B can be formed through the wall of the catheter body 152 to communicate with the intermediate lumen 114B.

[0030] In one embodiment, once the distal tip structure 170 is mated with the second portion 156, the helical plug 180 may be removed from the lumen 114. In one embodiment, the helical plug 180 may be formed of a sacrificial material. During the process of tipping the second portion 156 with the distal tip structure 170, a portion of the helical plug 180 may melt and fuse with the inner wall of the lumen 114 across the junction between the second portion 156 and the distal tip structure 170. Thus, the helical plug 180 may provide additional support across the junction to ensure a secure bond. As shown in FIG. 8C, once the distal tip structure 170 is mated with the second portion 156, the inner diameter of the helical plug 180 may be enlarged.

[0031] In one embodiment, one or both of the first portion 154 and the transition portion 158, i.e., the distal tip structure 170, can be formed from a first material and the second portion 156 can be formed from a second material. In one embodiment, the first material can exhibit different mechanical properties than the second material. In one embodiment, either the first material or the second material can be a plastic, polymer, polyurethane, composite material, elastomer, or the like. In one embodiment, the first material can exhibit mechanical properties of a stiffer or harder durometer while the second material can exhibit mechanical properties of a softer or softer durometer.

[0032] In one embodiment, the helical plug 180 can be formed from the same material as either the first material of the distal tip structure 170 or the second material of the second portion 156. In one embodiment, the helical plug 180 can be formed from a third material that is different from both the first material and the second material. In one embodiment, the third material can be a plastic, polymer, elastomer, polyurethane, combinations thereof, or the like.

[0033] In one embodiment, one or more of the distal end 218 of the second portion 156, the plug 252, the helical plug 180, and the distal tip structure 170 may be placed in a mold to couple the distal tip structure 170 to the second portion 156. Optionally, a mandrel (not shown) may be placed within a portion of the distal lumen 114C. Energy (such as heat, RF, or ultrasonic bonding) and / or pressure may be applied to the assembly in the mold to melt or fuse together the material of the distal end 218 of the second portion 156, the plug 252, the helical plug 180, and / or the distal tip structure 170 to form the catheter body 152 of the catheter 150. The mandrel defines a portion of the distal lumen 114C extending therethrough and may be removed once the catheter body 152 is formed.

[0034] In one embodiment, distal tip structure 170 can define one or both of transition portion 158 and first portion 154. In one embodiment, distal tip structure 170 can include transition portion 158 and can further define a recess configured to receive a proximal end of first portion 154. The proximal end of first portion 154 can be coupled to transition portion 158 using an adhesive, bonding, welding, or the like. Thus, first portion 154 can be formed from a third material or a fourth material different from the first, second, and third materials.

[0035] Some specific embodiments are disclosed herein, and although the specific embodiments are disclosed in some detail, the specific embodiments are not intended to limit the scope of the concept provided herein. Additional adaptations and / or modifications may be apparent to those skilled in the art, and the broader aspects also encompass these adaptations and / or modifications. Thus, one may deviate from the specific embodiments disclosed herein without departing from the scope of the concept provided herein.

Claims

1. 1. A method of forming a catheter, comprising: pushing out a proximal portion of a catheter body having a first catheter lumen and a second catheter lumen; and coupling a distal tip structure to the proximal portion; Coupling a distal tip structure to the proximal portion includes: disposing a spiral plug in a rolled configuration within the first catheter lumen; placing a plug within the second catheter lumen, the distal tip of the plug being aligned with the distal end of the second catheter lumen; aligning a lumen of the distal tip structure with the first catheter lumen; and coupling a proximal end of the distal tip structure to a distal end of the proximal portion.

2. forming the helical plug; forming the helical plug providing a tube having an outer diameter equal to or greater than the inner diameter of the first catheter lumen; cutting the tube longitudinally; and 10. The method of claim 1, comprising winding the tube into a helical shape having an outer diameter equal to or less than an inner diameter of the first catheter lumen.

3. The method of claim 1 or 2, wherein the helical plug engages the first catheter lumen with an interference fit.

4. The method of claim 1 or 2, wherein coupling the proximal end of the distal tip structure to the distal end of the proximal portion comprises gluing, bonding or welding the distal tip structure to the proximal portion.

5. 3. The method of claim 1 or 2, wherein coupling the proximal end of the distal tip structure to the distal end of the proximal section comprises adhering, bonding or welding the helical plug to the inner surface of the first catheter lumen and to one or both of the distal tip structure and the proximal section.

6. The method of claim 1 or 2, further comprising perforating a portion of the first catheter lumen adjacent to the spiral plug.

7. 3. The method of claim 1 or 2, wherein the distal tip structure is formed from a first material, the proximal portion is formed from a second material, and the spiral plug is formed from a third material, the second material being different from one or both of the first material and the third material.

8. The method of claim 7 , wherein the second material has softer, i.e., softer, durometer mechanical properties relative to the first material.

9. The method of claim 1 or 2, wherein the distal tip structure includes one or both of a first portion and a transition portion.

10. The method of claim 9 , wherein the first portion defines a single lumen and an outer diameter that is smaller than an outer diameter of the proximal portion.

11. The method of claim 10 , wherein the transition section defines a tapered profile extending from an outer diameter of the first section to an outer diameter of the proximal section.

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