Patent Publication Number: US-11654263-B2

Title: Medical catheter

Description:
This application claims the benefit of U.S. Provisional Application No. 62/680,792, filed Jun. 5, 2018, and entitled, “MEDICAL CATHETER,” the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to a medical catheter. 
     BACKGROUND 
     A medical catheter defining at least one lumen has been proposed for use with various medical procedures. For example, in some cases, a medical catheter may be used to deliver a medical device and/or composition within vasculature of a patient. 
     SUMMARY 
     In some examples, this disclosure describes a catheter that includes a push assembly and an elongate body including an inner liner defining an entry port into a lumen of the elongate body and an outer jacket. The push assembly may include an elongate member extending from a proximal portion to a distal portion. A cross-section of the distal portion of the elongate member may be D-shaped and taper in a distal direction. Distal to a proximal end of the elongate body, a first portion of the elongate member may be positioned between a portion of the inner liner and a portion of the outer jacket, and proximal to the proximal end of the elongate body, a second portion of the elongate member may be positioned outside of the outer jacket and the inner liner. The second portion of the push assembly may be proximal to the first portion. 
     In some examples, the disclosure describes a catheter that includes a push assembly and an elongate body including an inner liner defining an entry port into a lumen defined by the elongate body and an outer jacket. The push assembly may include an elongate member extending from a proximal portion to a distal portion. The distal portion elongate member may define a substantially constant taper in a distal direction from a circular cross-section to a D-shaped cross-section at a distal end of the elongate member. Distal to a proximal end of the elongate body, a first portion of the distal portion of the elongate member may be positioned between a portion of the inner liner and a portion of the outer jacket, and proximal to the proximal end of the elongate body, a second portion of the distal portion of the elongate member and the proximal portion of the elongate member may be positioned outside of the outer jacket and the inner liner. 
     In some examples, the disclosure describes a method of forming a catheter, the method including inserting an elongate member of a push assembly between an inner liner and an outer jacket of an elongate body. The elongate member may extend from a proximal portion to a distal portion. A cross-section of the distal portion may be D-shaped and taper in a distal direction. The method also include heating at least one of the inner liner or the outer jacket to reflow material around the elongate member. The inner liner may define an entry port into a lumen defined by the elongate body. After insertion and advancement of the elongate member distal to a proximal end of the elongate body, a first portion of the push assembly may be positioned between a portion of the inner liner and a portion of the outer jacket, and proximal to the proximal end of the elongate body, a second portion of the push assembly may be positioned outside of the outer jacket and the inner liner. 
     Clause 1. A catheter comprising: an elongate body comprising: an inner liner defining an entry port into a lumen defined by the elongate body; and an outer jacket; and a push assembly including an elongate member extending from a proximal portion to a distal portion, wherein a cross-section of the distal portion is D-shaped and tapers in a distal direction, wherein distal to a proximal end of the elongate body, a first portion of the elongate member is positioned between a portion of the inner liner and a portion of the outer jacket, and proximal to the proximal end of the elongate body, a second portion of the elongate member is positioned outside of the outer jacket and the inner liner, and wherein the second portion of the push assembly is proximal to the first portion. 
     Clause 2. The catheter of Clause 1, wherein the distal portion of the elongate member comprises the first portion of the elongate member, and wherein the second portion of the elongate member comprises the proximal portion of the elongate member and at least a portion of the distal portion of the elongate member. 
     Clause 3. The catheter of Clause 1 or 2, wherein the distal portion of the elongate member comprises a first section having a first D-shape in cross-section and a second section having a second D-shape in cross-section, the first section being proximal to the second section, wherein a first cross-sectional area of the first D-shape is greater than a second cross-sectional area of the second D-shape. 
     Clause 4. The catheter of any one of Clauses 1 through 3, wherein the distal portion of the elongate member defines a substantially constant taper in the distal direction. 
     Clause 5. The catheter of any one of Clauses 1 through 3, wherein the distal portion of the elongate member defines a step-wise taper in the distal direction. 
     Clause 6. The catheter of any one of Clauses 1 through 5, wherein a cross-sectional area of the proximal portion is greater than a cross-sectional of the distal portion. 
     Clause 7. The catheter of any one of Clauses 1 through 6, wherein a cross-section of the proximal portion of the elongate member is circular. 
     Clause 8. The catheter of any one of Clauses 1 through 7, wherein a greatest cross-sectional dimension of a distal end of the elongate member is about 50 micrometers to about 200 micrometers. 
     Clause 9. The catheter of any one of Clauses 1 through 8, wherein a length of the distal portion of the elongate member is about 5 cm to about 20 cm. 
     Clause 10. The catheter of any one of Clauses 1 through 9, wherein at least one surface of the elongate member comprises a rough surface. 
     Clause 11: The catheter of any one of Clauses 1 through 10, wherein the elongate member is solid. 
     Clause 12: The catheter of any one of Clauses 1 through 11, wherein the elongate member does not define an inner lumen. 
     Clause 13. A method of forming a catheter, the method comprising: inserting an elongate member of a push assembly between an inner liner and an outer jacket of an elongate body, wherein the elongate member extends from a proximal portion to a distal portion, wherein a cross-section of the distal portion is D-shaped and tapers in a distal direction; and heating at least one of the inner liner or the outer jacket to reflow material around the elongate member, wherein the inner liner defines an entry port into a lumen defined by the elongate body, wherein, after insertion and advancement of the elongate member distal to a proximal end of the elongate body, a first portion of the push assembly is positioned between a portion of the inner liner and a portion of the outer jacket, and proximal to the proximal end of the elongate body, a second portion of the push assembly is positioned outside of the outer jacket and the inner liner. 
     Clause 14. The method of Clause 13, wherein the distal portion of the elongate member comprises the first portion of the elongate member, and wherein the second portion of the elongate member comprises the proximal portion of the elongate member and at least a portion of the distal portion of the elongate member. 
     Clause 15. The method of Clause 13 or 14, wherein a cross-sectional area of the proximal portion is greater than a cross-sectional of the distal portion. 
     Clause 16. The method of any one of Clauses 13 through 15, wherein a cross-section of the proximal portion of the elongate member is circular. 
     Clause 17. The method of any one of Clauses 13 through 16, wherein a length of the distal portion of the elongate member is within a range between about 5 cm and about 20 cm. 
     Clause 18. The method of any one of Clauses 13 through 17, further comprising, before inserting the elongate member between the inner liner and the outer liner, forming the taper in the distal portion of the elongate member. 
     Clause 19. The method of Clause 18, wherein forming the taper comprises at least one of grit blasting, sanding, or grinding the distal portion of the elongate member. 
     Clause 20. The method of Clause 18 or 19, wherein forming the taper comprises forming at least one rough surface on the elongate member. 
     Clause 21. The method of any one of Clauses 18 through 20, wherein forming the taper comprises: forming a first D-shape; and forming a second a second D-shape distal to the first D-shape, wherein a cross-sectional area of the first D-shape is greater than a cross-sectional area of the second D-shape. 
     Clause 22. The method of any one of Clauses 18 through 21, wherein forming the taper comprises forming a substantially constant taper in the distal direction. 
     Clause 23: The method of any one of Clauses 13 through 22, wherein the elongate member is solid. 
     Clause 24: The method of any one of Clauses 13 through 23, wherein the elongate member does not define an inner lumen. 
     Clause 25. A catheter comprising: an elongate body comprising: an inner liner defining an entry port into a lumen defined by the elongate body; and an outer jacket; and a push assembly including an elongate member extending from a proximal portion to a distal portion, wherein the distal portion elongate member defines a substantially constant taper in a distal direction from a circular cross-section to a D-shaped cross-section at a distal end of the elongate member, wherein distal to a proximal end of the elongate body, a first portion of the distal portion of the elongate member is positioned between a portion of the inner liner and a portion of the outer jacket, and proximal to the proximal end of the elongate body, a second portion of the distal portion of the elongate member and the proximal portion of the elongate member is positioned outside of the outer jacket and the inner liner. 
     Clause 26. The catheter of Clause 25, wherein the distal portion of the elongate member comprises the first portion of the elongate member, and wherein the second portion of the elongate member comprises the proximal portion of the elongate member and at least a portion of the distal portion of the elongate member. 
     Clause 27. The catheter of Clause 25 or 26, wherein the distal portion of the elongate member comprises a first section having a first D-shape in cross-section and a second section having a second D-shape in cross-section, the first section being proximal to the second section, wherein a first cross-sectional area of the first D-shape is greater than a second cross-sectional area of the second D-shape. 
     Clause 28: The catheter of any one of Clauses 25 through 27, wherein the elongate member is solid. 
     Clause 29: The catheter of any one of Clauses 25 through 28, wherein the elongate member does not define an inner lumen. 
     The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a conceptual side view of an example catheter, which includes an elongate body, a push assembly, and a handle. 
         FIG.  2    is a conceptual cross-sectional view of a portion of the example catheter of  FIG.  1    and an outer catheter. 
         FIG.  3    is a conceptual cross-sectional view of an example elongate member of the push assembly of the catheter of  FIGS.  1  and  2    taken along line  3 - 3  in  FIG.  2   . 
         FIG.  4    is a conceptual cross-sectional view of an example elongate member of the push assembly of the catheter of  FIGS.  1  and  2    taken along line  4 - 4  in  FIG.  2   . 
         FIG.  5    is a conceptual cross-sectional view of an example elongate member of the push assembly of the catheter of  FIGS.  1  and  2    taken along line  5 - 5  in  FIG.  2   . 
         FIG.  6    is a conceptual cross-sectional view of the catheter of  FIGS.  1  and  2    taken along line  6 - 6  in  FIG.  2   . 
         FIGS.  7 A and  7 B  are conceptual cross-sectional views of examples of the catheter of  FIGS.  1  and  2    taken along line  7 - 7  in  FIG.  2   . 
         FIGS.  8 A and  8 B  are conceptual cross-sectional views of examples of the catheter of  FIGS.  1  and  2    taken along line  8 - 8  in  FIG.  2   . 
         FIG.  9    is a conceptual perspective view of the anchor member of  FIGS.  1 ,  2 ,  6 ,  7 A,  7 B,  8 A, and  8 B . 
         FIGS.  10 A and  10 B  are conceptual perspective views of the push assembly of  FIGS.  1 ,  2 ,  6 ,  7 A, and  7 B . 
         FIG.  11    is a conceptual perspective view of an example push assembly, such as the push assembly of  FIGS.  1 ,  2 ,  10 A and  10 B , further including a radiopaque band. 
         FIGS.  12  and  13    are conceptual cross-sectional views of example anchor members, such as the anchor member of  FIGS.  1  and  2   , with an inner surface and/or an outer surface defining a non-semicircular surface. 
         FIG.  14    is a conceptual side view of an example of the anchor member of the push assembly of  FIGS.  2 ,  10 A, and  10 B  and a distal portion of the elongate member of the push assembly of  FIGS.  2 ,  10 A, and  10 B , before the anchor member and the elongate member are mechanically connected together to form the push assembly. 
         FIG.  15    is a conceptual side view of the push assembly of  FIG.  14    after the anchor member and the elongate member are mechanically connected together to form the push assembly. 
         FIG.  16    is a conceptual perspective view of a portion of an example of the elongate member of  FIGS.  1 ,  2 ,  10 A,  10 B, and  11   . 
         FIG.  17    is a flowchart illustrating an example method of assembling the example catheter shown in  FIGS.  1  and  2   . 
     
    
    
     DETAILED DESCRIPTION 
     In some examples, a medical catheter (“catheter”) described herein includes a push assembly and an elongate body including an inner liner and an outer jacket. The push assembly includes an elongate member (also referred to herein as a shaft) and an anchor member at a distal end of the push assembly. In some examples, the push assembly includes only one anchor member at the distal end of the push assembly, while in other examples, the push assembly includes a plurality of anchor members. The anchor member is configured to facilitate attachment of the elongate member to the inner liner and outer jacket of the elongate body. The anchor member may be positioned at a distal end of the elongate member. 
     The outer jacket and the inner liner, alone or in combination with other elements, may form the elongate body, may be a distal portion of the catheter. The elongate body defines at least one lumen through which a medical device (e.g., a catheter, guidewire, filter, stent delivery system, and the like), therapeutic agent, or other element can be introduced into vasculature or other tissue sites of a patient. The inner liner may define an entry port into the lumen. At least a portion of the elongate member of the push assembly may extend proximal of the outer jacket and the inner liner. In examples in which the catheter is part of an intravascular catheter system and is used in conjunction with an outer catheter, the elongate body of the catheter may be used to effectively extend the reach of the outer catheter. For example, the elongate body of the catheter may be fully or partially pushed through a lumen of the outer catheter until the entire or part of the elongate body extends past a distal end of the outer catheter, while the push assembly remains fully or partially within the lumen of the outer catheter. The push assembly has a lower profile than the elongate body, and, as a result, may occupy less space within the outer catheter lumen than the elongate body of the catheter. Thus, the push assembly may both facilitate pushability of the catheter through the outer catheter and/or through vasculature of a patient, while still enabling relatively large medical devices to be introduced through the outer catheter lumen to reach the lumen of the catheter. 
     In some examples, the catheter described herein may also help delivery to or past a diseased region or the body. For example, a diseased region may include heavy tortuosity and/or calcification and the catheter may be better suited for navigation through such heavy tortuosity and/or calcification than the outer catheter due to its flexibility and lower profile. In some examples, a clinician may push the catheter out of a distal end of the outer catheter upon the approach of the outer catheter to such a region that would be difficult or impossible for the outer catheter to extend through. In some examples, the catheter may be said to “telescope” out of the outer catheter when it is pushed out of a distal end of the outer catheter. 
     The elongate body, including the inner liner and outer jacket, may define a proximal end. Distal to the proximal end, a portion of the push assembly including the anchor member may be positioned between the inner liner and outer jacket. The anchor member may extend only partially around an outer perimeter of the inner liner. Proximal to the proximal end of the elongate body, a portion of the push assembly proximal to the portion including the anchor member may be positioned outside of the outer jacket. 
     In some examples, the anchor member may be configured to facilitate manufacture of a catheter. For example, the anchor may define a beveled distal edge to assist with placement of the anchor member, including insertion and advancement of the anchor member between the outer jacket and the inner liner. As another example, the anchor member may define a slot extending from a proximal end of the anchor member and towards a distal end of the anchor member. The slot may facilitate attachment of the elongate member to the anchor member as the slot may be configured such that a distal end of the elongate member may be positioned at least partially within the slot and may be welded to the anchor. The slot may be configured such that welding material may be placed between the anchor member and the elongate member, such as in a gap within the slot between the anchor member and the elongate member when the distal end of the elongate member is positioned at least partially within the slot, such that the welding material may not add to the profile of the push assembly. 
     In some examples, an inner surface and/or an outer surface of the anchor member may be a non-semicircular surface such as, for example, a surface defining a plurality of notches or waves and/or a textured and/or etched surface. Such a non-circular surface may aid in securing the anchor member between the inner liner and the outer jacket by providing greater surface area that may be bonded to the inner liner and/or outer jacket including, for example, by reflow of material of the inner liner and/or outer jacket. 
     In some examples, the catheter may include one or more radiopaque markers to facilitate visualization of the catheter during a medical procedure. The one or more radiopaque markers can be located, for example, on the anchor member, on the elongate member, or in any suitable place or combination of places, to assist with visualization and placement of the catheter, with respect to, for example, an outer catheter and/or a target tissue site. In some examples, the anchor is at least partially radiopaque and/or a radiopaque marker is positioned at or near the entry port into the elongate body of the catheter. This radiopaque marker placement may enable a clinician to relatively quickly ascertain the location of the entry port of the lumen of the catheter. 
     In some examples, the catheter may be configured to facilitate maneuverability. For example, the outer jacket may vary in stiffness along its length, which may help aid maneuverability of the catheter within vasculature of a patient. As another example, a reinforcement member may be positioned between the inner liner and the outer jacket, may be distal to and/or abutting the anchor member, and may aid in the strength and/or maneuverability of the catheter within vasculature of a patient. 
     In some examples, the elongate member of the push assembly may taper in a distal direction to enable the distal portion of the elongate member to better approximate a profile of the anchor member. By tapering the elongate member instead of forming the entire elongate member to have the lower profile, the proximal portion of the elongate member may still have a size and strength sufficient for pushing the catheter within the vasculature and/or sufficient size for gripping by a user. In some of these examples, as well as some other examples, the elongate member may be a solid member having a round (e.g., circular) cross-section. That is, the elongate member may not define a central lumen or other opening in its cross-section. 
     In some examples, the catheter may facilitate differentiation from other devices used in conjunction with the catheter and/or between elements of the catheter. For example, a sleeve may surround at least a portion of the elongate member, such as a portion proximal to the anchor member. In some examples, the sleeve may be a different color than the elongate member, the elongate body, a guidewire, and/or other devices used with the catheter in order to help visually distinguish the sleeve. The sleeve can also include other features to help facilitate usage of the sleeve. For example, the sleeve may include one or more bands including one or more partial cuts extending partially through a radial thickness of the sleeve and/or one or more markers. In some examples, the sleeve may include a textured surface. In some examples, partial cuts and/or a textured surface may aid in tactile differentiation of the sleeve from other components. In some examples, one or more bands including one or more partial cuts and/or markers may aid in visual differentiation of the sleeve. Visual and/or tactile differentiation of the sleeve may enable the elongate member to be discerned from other elements including, for example, an outer catheter, a guidewire, or other delivery devices or components in use with the catheter described herein. 
       FIG.  1    is a conceptual side view of an example catheter  100 , which includes an elongate body  102 , a push assembly  108 , and a handle  101 .  FIG.  2    is a conceptual cross-sectional view of a portion of catheter  100  of  FIG.  1    and an outer catheter  110 . Catheter  100  defines a longitudinal axis X. Elongate body  102  includes an inner liner  104  and an outer jacket  106 . As shown in  FIG.  1   , elongate body  102  may define a proximal end  10  and a distal end  12 . 
     In some examples, catheter  100  may be part of an assembly that includes an outer catheter  110  defining a lumen  111 , through which catheter  100  may be introduced in order to access, for example, a distal target site within vasculature of a patient. Thus, at least a portion of outer catheter  110  may be configured to surround catheter  100 . Outer catheter  110  may further define distal opening  113  and, in some examples, at least a portion of catheter  100  may be configured to extend through distal opening  113  and distally of outer catheter  110 , as shown in  FIG.  2   . For example, catheter  100  may be configured to extend out of distal opening  113  of outer catheter  110  to extend through heavy tortuosity or calcification within a body vessel. Catheter  100  may have a smaller radial profile and may be more flexible than outer catheter  110  such that it may more easily navigate through heavy tortuosity or calcification within a body vessel than outer catheter  110 . 
     In some examples, an outer radial profile of elongate body  102  of catheter  100  may be similar in a radial shape and/or size of at least a distal portion of lumen  111  of outer catheter  110  such that catheter  100  may fit relatively snugly inside of outer catheter  110  when elongate body is at least partially within outer catheter  110 . This may help to define a relatively smooth transition between elongate body  102  and outer catheter  110  when only a portion of elongate body  102  extends distally of distal opening  113  of outer catheter  110  and another portion remains within lumen  111  of outer catheter  110  and/or when a proximal end of elongate body  102  abuts a distal end of outer catheter  110 . This relatively smooth transition and/or snug fit may provide certain advantages. For example, fluids may be easier to deliver through the lumen  111  of outer catheter  110  and the lumen  105  of elongate body  102  without leakage. As an additional example, devices and/or other elements may be easier to advance from lumen  111  of outer catheter  110  to lumen  105  of elongate body  102  because the transition between lumen  111  and lumen  105  may be relatively smooth such that components being delivered may not get caught at a transition from lumen  111  to lumen  105 . 
     Although catheter  100  is shown as extending out distal opening  113  of outer catheter  100  such that proximal end  10  of elongate body  102  is distal to distal opening  113 , in some medical procedures, catheter  100  may be positioned relative to outer catheter  110  such that proximal end  10  of elongate body  102  is proximate to distal opening  113 . For example, entry port  109  of elongate body  102 , described in further detail below, may be positioned within lumen  111  of outer catheter  110 , such that an interventional medical device or another medical device can be introduced from lumen  111  of outer catheter  110  into lumen  105  of elongate body  102  without exiting lumen  111 . 
     In some examples, as shown in  FIG.  1   , catheter  100  may include an atraumatic tip  14  to minimize adverse interactions with patient tissue during advancement of catheter  100  within a body vessel. 
     Elongate body  102  is configured to provide a delivery vessel on catheter  100  that may extend distally of outer catheter  110  to telescope out of a distal end of outer catheter  110  and effectively extend a reach of a catheter within vasculature of a patient and enable delivery of devices, agents, and/or any other suitable elements to target sites that may be difficult for outer catheter  110  to reach. In some examples, elongate body  102  may include an inner liner  104  and outer jacket  106  that may provide multiple layers between which push assembly  108  may be inserted to attach push assembly  108  to elongate body  102 . This may provide for a relatively strong attachment between push assembly  108  and elongate body  102 , as well as maintain relatively smooth outer and inner surfaces of elongate body  102  at the portion of elongate body  102  attached to push assembly  108 . 
     Inner liner  104  of elongate body  102  defines lumen  105  and outer jacket  106  defines lumen  107 . In some examples, at least a portion of inner liner  104  may be positioned within lumen  107  of outer jacket  106 . In some examples, inner liner  104  may extend within the full length of lumen  107  of outer jacket  106 . In other examples, however, inner liner  104  may terminate prior to a distal end of outer jacket  106  or may extend past a distal end of outer jacket  106 . Although elongate body  102  is shown as a tubular body in  FIG.  1   , elongate body  102  may have any suitable configuration. 
     Inner liner  104 , alone or in combination with outer jacket  106 , may define entry port  109  into lumen  105 . Entry port  109  may extend from a proximal end  138  to a distal end  140  along a length of elongate body  102 . In some examples, entry port  109  may be angled from distal end  140  to proximal end  138  due to the tapered shape of the elongate body  102 . Entry port  109  may be formed by skiving at least part of portion  120  of elongate body  102 . In some examples, entry port  109  may have a length, measured from proximal end  138  to distal end  140  along longitudinal axis X, of about 2 centimeters (cm) to about 10 cm (e.g., 2 cm to 10 cm or nearly 2 cm to 10 cm, to the extent permitted by manufacturing tolerances), such as about 3.5 cm to about 4.5 cm or about 4 cm. It is believed that a tapered entry port  109  having a relatively longer length and being angled from distal end  140  to proximal end  138  may help contribute to smooth delivery of a medical device (e.g., an interventional medical device) into inner lumen  105  of elongate body  102  via entry port  109  by guiding the medical device into inner lumen  105 . 
     Push assembly  108  may be configured to enable a clinician to position elongate body  102  with respect to outer catheter  110  and/or with respect to patient vasculature. For example, a proximal portion of push assembly  108  may be configured to be gripped and moved by the clinician to position (e.g., advance distally or proximally, and/or rotate) elongate body  102  within vasculature of a patient. In some examples, push assembly  108  may be used to advance elongate body  102  with respect to outer catheter  110  to advance elongate body  102  within outer catheter  110  and/or extend all or a portion of elongate body  102  distal of outer catheter  110  to access vasculature distal to outer catheter  110 . Push assembly  108  may include any suitable length. In some examples, a length of push assembly  108  may be approximately 100 cm to approximately 150 cm, such as about 125 cm, measured along longitudinal axis X and from a distal end of handle  101  to a distal end  128  of anchor or measured from a distal end of handle  101  to a distal end of elongated member  114 . In some examples, push assembly  108  includes an elongate member  114  and an anchor member  116 . For clarity, a portion of anchor member  116 , which is positioned behind inner liner  104  in the illustrated view, is shown in phantom. In some examples, elongate member  114  may include a distal end  118  and anchor member  116  may be positioned at distal end  118  of elongate member  114 . In some examples, push assembly  108  may not include any other anchor member at distal end  118  other than anchor member  116 . 
     In some examples, at least a portion of push assembly  108  is positioned between at least adjacent portions (e.g., radially adjacent portions) of inner liner  104  and outer jacket  106 . For example, at least a portion of push assembly  108  may be positioned radially inward of outer jacket  106  and radially outward of inner liner  104  such that the portion of push assembly  108  is between outer jacket  106  and inner liner  104 . In some examples, the portion of push assembly  108  between inner liner  104  and outer jacket  106  may have a length of approximately 4 cm. Positioning at least a portion of push assembly  108  between portions of inner liner  104  and outer jacket  106  may aid in mechanically connecting push assembly  108  and elongate body  102  in a manner that enables push assembly  108  to transmit pushing forces and, in some examples, rotational forces, to elongate body  102 . In addition, positioning at least a portion of push assembly  108  between inner liner  104  and outer jacket  106  may enable elongate body  102  to have relatively smooth inner and outer surfaces at the portion of elongate body  102  attached to push assembly  108 . 
     In some examples, elongate body  102  may include a tapered portion  120 . For example, portions of inner liner  104  and outer jacket  106 , as shown in  FIG.  2   , corresponding to tapered portion  120  of elongate body  102  may be tapered in a proximal direction. The tapering of elongate body  102  at tapered portion  120  may enable elongate body  102  to more easily be retracted into outer catheter  110 . For example, during or after use of catheter  100 , a clinician may desire to retract at least a portion of elongate body  102  within outer catheter  110  by retracting push assembly  108  proximally with respect to outer catheter  110 . Tapered portion  120  may allow for smoother entry of elongate body  102  into outer catheter  110 . 
     Additionally, the tapered shape of tapered portion  120  may be configured facilitate attachment of push assembly  108  to elongate body  102 . For example, the tapered shape may allow for anchor member  116  to support entry port  109  while also allowing a portion of elongate member  114  proximal to anchor member  116  to be positioned between inner liner  104  and outer jacket  106 , which may increase bond tensile strength between the push assembly  108  and the elongate body  102 . The bond tensile strength between push assembly  108  and elongate body  102  may decrease with a shorter length of elongate member  114  positioned between inner liner  104  and outer jacket  106 . Thus, if only anchor member  116  (and not elongate member  114 ) was positioned between inner liner  104  and outer jacket  106 , then the bond tensile strength between push assembly  108  and elongate body  102  may decrease. The decreased bond tensile strength may adversely affect the ability for push assembly  108  to transfer pushing and/or rotational forces to elongate body  102  without compromising the mechanical connection between push assembly  108  and elongate body  102 . 
     Further, because a distal portion of elongate member  114  may be relatively flexible (compared to a more proximal portion of elongate member  114 ), as described in further detail below, positioning the distal portion of elongate member  114  between inner liner  104  and outer jacket  106  may help prevent the junction of push assembly  108  and elongate body  102  from being undesirably stiff. 
     In some examples, distal to proximal end  10  of elongate body  102 , a portion of push assembly  108  is positioned between adjacent portions of inner liner  104  and outer jacket  106 . Proximal to proximal end  10  of elongate body  102 , a portion of push assembly  108  is positioned outside of outer jacket  106  and inner liner  104 . The portion of push assembly  108  positioned between adjacent portions of inner liner  104  and outer jacket  106  may comprise anchor member  116 . The portion of push assembly  108  positioned outside of outer jacket  106  and inner liner  104  may be proximal to the portion positioned between adjacent portions of inner liner  104  and outer jacket  106 . 
     Anchor member  116  may have any suitable shape and size. In some examples, at least an outer surface of anchor member  116  may define a partial-ring shape as shown in further detail below with reference to  FIGS.  6 - 9   . In other examples, however, anchor member  116  may define other shapes. The partial-ring shape of anchor member  116  may provide one or more advantages. For example, the partial-ring shape may provide support to inner liner  104  and outer jacket  106  to prevent collapse of proximal ends of inner liner  104  and outer jacket  106  and thus help maintain the open state of entry port  109  into lumen  105  defined by inner liner  104  such that other catheters or devices may be inserted into lumen  105 . 
     In some examples, and as described in further detail below with respect to  FIG.  6   , anchor member  116  may have an inner perimeter that is less than the outer perimeter of inner liner  104  and anchor member  116  may extend only partially around an outer perimeter of inner liner  104 . For example, anchor member  116  may extend about 140 degrees to about 160 degrees around an outer perimeter of inner liner  104 . More particularly, in some examples, anchor member  116  may extend about 160 degrees around the outer perimeter of inner liner  104 . In some examples, anchor member  116  is radiopaque, and extending only partially about the outer perimeter of inner liner  104  may enable anchor member  116  to indicate a rotational orientation (e.g., rotational position about longitudinal axis X) of elongate body  102  (e.g., entry port  109 ) within vasculature of a patient. This may enable a clinician to better position catheter  100  relative to outer catheter  110 . 
     In addition, extending only partially about the outer perimeter of inner liner  104  may enable anchor member  116  to be positioned within tapered portion  120  of elongate body  102 . This may enable anchor member  116  to be positioned at entry port  109  to indicate the location thereof, and may also enable anchor member  116  to provide structural support to tapered portions of the inner liner  104  and outer jacket  106 . A full-ring shape would not be able to be located within the tapered portion  120  of elongate body  102  but instead would need to be located distal to the tapered portion  120  and thus distal to the entry port  109  in order to fit between inner liner  104  and outer jacket  106  without being exposed and would thus not be able to include a marker to indicate a location of the entry port  109 . 
     In some examples, however, as shown in  FIG.  2   , a proximal end of anchor member  116  is positioned proximate to the distal end  140  of entry port  109 . For example, a proximal end of anchor member  116  may be aligned with distal end  140  of entry port  109 , such that anchor member  116  is fully positioned within the portion of elongate body  102  defining a circular outer perimeter in cross-section. As another example, a proximal end of anchor member  116  may not be exactly aligned with distal end  140  of entry port  109 , but within 4 millimeters (mm), such as within 2 mm or less, of distal end  140  of entry port  109  in a proximal or a distal direction. In these examples, a substantial length of that anchor member  116  is positioned within the portion of elongate body  102  defining a circular outer perimeter in cross-section. 
     This partial-ring shape of anchor member  116  may also be advantageous over a full-ring shape because it may be less likely to cause inner liner  104  to bunch during insertion of anchor member  116  between outer jacket  106  and inner liner  104  because anchor member  116  does not extend fully about an outer perimeter of inner liner  104 . 
     In some examples anchor member  116  may define a beveled distal edge  124 . Beveled distal edge  124  may allow anchor member  116  to more easily be inserted and advanced between inner liner  104  and outer jacket  106  than examples in which an anchor member has a straight edge. For example, beveled distal edge  124  may enable anchor member  116  to be more easily inserted between inner liner  104  and outer jacket  106  by providing a narrow profile of anchor member  116  at distal end  128 , which leads anchor member  116  into the space between inner liner  104  and outer jacket  106 . Additionally, beveled distal edge  124  may provide a smooth distal profile of anchor member  116  that enables less resistance to advancement of anchor member  116  between and with respect to inner liner  104  and outer jacket  106  than a profile including a straight edge and/or sharp corners which may be more likely to catch on inner liner  104  and/or outer jacket  106 . 
     Inner liner  104  may be formed from any suitable material, such as, but not limited to polytetrafluorethylene (PTFE). In some examples, outer jacket  106  may comprise one or more polymers. In some examples, outer jacket  106  may have a hydrophilic coating. For example, the hydrophilic coating may be positioned over the entire outer surface of outer jacket  106  or only along a portion of outer jacket, such as only along a distal-most portion of outer jacket  106 . In some examples, a hydrophilic coating is positioned over the distal-most approximately 15 cm to approximately 25 cm of outer jacket  106  (e.g., the distal-most 15 cm to 25 cm to the extent permitted by manufacturing tolerances), such as the distal-most approximately 20 cm to approximately 22 cm of outer jacket  106 , or the distal-most approximately 21 cm of outer jacket  106 , the distances being measured from distal end of outer jacket  106 , which may correspond to distal end  12  of elongate body  102  in some examples. 
     In some examples, outer jacket  106  may include multiple sections having different stiffnesses. For example, outer jacket  106  may include a proximal section, corresponding with portion  136  of catheter  100 , and a distal section, corresponding with portion  129  of catheter  100  (shown in  FIG.  1   ), that is distal to the proximal section. In some examples, the proximal section may be approximately 1 cm to approximately 4 cm long, such as approximately 2.5 cm long or approximately 1.25 cm long. In some examples, the distal section may be approximately 15 cm to approximately 27 cm long, such as approximately 24 cm long to approximately 26 cm long, or approximately 25 cm long. The lengths may be measured along longitudinal axis X. 
     The distal section of outer jacket  106  may have a different stiffness than the proximal section. For example, the distal section may have a stiffness that is greater than a stiffness of the proximal section. In other examples, the distal section may have a stiffness that is less than the proximal section. Outer jacket  106  having a more stiff proximal section (relative to a distal outer jacket section) may help maintain the integrity of the proximal portion of inner lumen  105  of elongate body  102 , which may aid in introduction of medical devices into lumen  105  from entry port  109  without adversely impact the navigability of catheter  100  through vasculature of a patient. For example, outer jacket  106  having a more stiff proximal section may help distal end  140  of entry port  109  and a proximal-most portion of elongate body  102  resist deformation to help maintain lumenal integrity. 
     Outer jacket  106  may include any suitable number of sections having any suitable stiffnesses according to particular needs. In some examples, sections of outer jacket  106  may include different types of polymers, with a stiffer section comprising a stiffer polymer than a more flexible section comprising a softer polymer. In some examples, outer jacket  106  having multiple sections with different stiffnesses may provide improved functionality of outer jacket  106  including, for example, improved maneuverability of outer jacket  106  through the vasculature. For example, the distal section may have a stiffness that is less than a stiffness of the proximal section, which may allow the distal section improved flexibility for navigation through the vasculature. 
     In some examples, catheter  100  may further include a reinforcement member  126  positioned between a portion of inner liner  104  and a portion of outer jacket  106 . For clarity, a portion of reinforcement member  126 , which is positioned behind inner liner  104  in the illustrated view, is shown in phantom. Reinforcement member  126  may be any suitable structure configured to provide structural support to elongate body  102  and, in some examples, increase the structural integrity of elongate body  102 . For example, reinforcement member  126  may comprise a metal coil, a metal braid, or a combination thereof. In some examples, a distal end  128  of anchor member  116  may be positioned proximal to and spaced from reinforcement member  126 , such that there is a gap between distal end  128  of anchor member  116  and a proximal end  130  of reinforcement member  126 . Example gaps include, for example, gaps less than or equal to 4 mm, such as about 2 mm or less than 2 mm, measured along longitudinal axis X. In other examples, anchor member  116  may contact (e.g., abut) reinforcement member  126 , e.g., distal end  128  of anchor member  116  may contact proximal end  130  of reinforcement member  126 . In yet other examples, anchor member  116  and reinforcement member  126  may overlap in the longitudinal direction, e.g., by a length of about 2 mm or less, such as about 1 mm or less. 
     Anchor member  116  at distal end  118  of elongate member  114  may increase a surface area of a distal portion of push assembly  108  relative to examples of push assemblies including only elongate member  114  without anchor member  116 , which may provide certain advantages. For example, the increased surface area at the distal portion of push assembly  108  provided by anchor member  116  may improve tensile strength of catheter  100  by strengthening the bond between push assembly  108  and elongate body  102 . Additionally, the increased surface area at the distal portion of push assembly  108  provided by anchor member  116  may help prevent protrusion of elongate member  114  through outer jacket  106  when elongate member  114  is under compression, i.e., when a pushing force is applied to a proximal portion of elongate member  114  as catheter  100  is advanced through vasculature of a patient. For example, in examples without anchor member  116 , distal end  118  of elongate member  114  may pierce outer jacket  106  due to the relatively small surface area of distal end  118  of elongate member  114 . Anchor member  116 , however, helps distribute the pushing force and minimize any pressure points at the distal end of push assembly  108 . Additionally, anchor member  116  may help avoid bending of distal end  118  of elongate member  114  under outer jacket  106  by providing reinforcement to distal end  118  of elongate member  114 . 
       FIGS.  3 , 4 , and  5    are conceptual cross-sectional views of an example elongate member  114  of push assembly  108  of catheter  100  of  FIGS.  1  and  2    taken along lines  3 - 3 ,  4 - 4 , and  5 - 5 , respectively, in  FIG.  2   . Although lines  3 - 3 ,  4 - 4 , and  5 - 5  are shown as intersecting multiple elements of catheter  100  in  FIG.  1   , for clarity,  FIGS.  3 , 4 , and  5    show only the cross-section of elongate member  114 . As shown, elongate member  114  may taper in a distal direction. For example, in some examples and as shown in the illustrated example, a greatest cross-sectional dimension of elongate member  114  along line  5 - 5  may be smaller than a greatest cross-sectional dimension of elongate member  114  along line  3 - 3  and a greatest cross-sectional dimension of elongate member  114  along line  4 - 4 . In some examples and as shown in the illustrated example, a greatest cross-sectional dimension of elongate member  114  along line  4 - 4  may be smaller than a greatest cross-sectional dimension of elongate member  114  along line  3 - 3 . A transition between the cross-sections illustrated in  FIGS.  3 , 4 , and  5    may be stepwise, defined by a discrete tapered section, or defined by a substantially constant tapered section. 
     In some examples, a cross-section of a proximal portion of elongate member  114 , such as the cross-section along line  3 - 3 , may be round (e.g., circular). In some examples, this proximal portion of elongate member  114  having the round cross-section may include a proximal-most portion of elongate member  114  including a proximal end of elongate member  114 . In addition, in some examples, the proximal portion of elongate member  114 , the configuration of which may be represented by the cross-section along line  3 - 3 , may be both round in cross-section and solid (e.g., not hollow or defining any lumens). Elongate member  114  having a proximal portion that is solid and round in cross-section may exhibit a better push force transmission along catheter  110 , e.g., relative to an elongate body that has a proximal portion that is a hollow in cross-section and/or non-round (e.g., rectangular) in cross-section. 
     In some examples, a greatest cross-sectional dimension of the proximal portion of elongate member  114 , e.g., as shown at line  3 - 3 , is approximately 0.3 mm to approximately 1 mm, such as approximately 0.4 mm to approximately 0.5 mm. However, other cross-sectional dimensions of elongate member  114  may be used in other examples. 
     In some examples, as in the illustrated example, a portion of elongate member  114  having a circular cross section may be proximal to a portion of elongate member  114  having a D-shaped cross-section. The portions of elongate member  114  having the D-shaped cross-sections may define a smaller profile than the proximal portion of elongate member  114  defining the round (e.g., circular) cross-section, such that the portions of elongate member  114  defining the D-shaped cross-sections may define the “tapered” portions of elongate member  114 . For example, a cross-section of an intermediate and/or a distal portion of elongate member  114 , such as the cross-section along line  4 - 4  or line  5 - 5 , may be D-shaped. In these examples, one half of elongate member  114  in cross-section may be substantially flat (e.g., planar to extent permitted by manufacturing tolerances) and the other longitudinal half of elongate member  114  in cross-section may be round (e.g., semi-circular). 
     In examples in which a distal portion of elongate member  114  tapers in a distal direction, a first section of the distal portion may define a first D-shaped cross section having a first cross-sectional area, e.g., a shown in  FIG.  4   , and a second section of the distal portion distal to the first section may define a second D-shaped cross section having a second cross-sectional area, where the second cross-sectional area is less than the first cross-sectional area. 
     The difference in cross-sectional area may be due to, for example, a profile height of elongate member  114  in the first and second sections of the distal portion. In some examples, a D-shaped cross-section along line  4 - 4  may include profile height (e.g., from the flat surface of the “D” to the crest of the curved surface of the “D”) of approximately 0.1 mm to about 0.5 mm, such as approximately 0.2 mm to approximately 0.3 mm. In some examples, a D-shaped cross-section along line  5 - 5  is less than the profile height along line  4 - 4 , and may include profile height of approximately 0.05 mm and 0.2 mm. Other profile heights may be used in other examples and may depend on various factors, such as a size of lumen  105  or anchor member  116 . The profile height at the distal-most section of the distal portion of elongate member  114  may be selected such that when elongate member  114  is mechanically connected to anchor member  116 , elongate member  114  does not protrude from anchor member  116  in the cross-sectional dimension (orthogonal to longitudinal axis X) or protrudes a relatively minimal amount from anchor member  116  to reduce occupying space that limits the cross-sectional size of lumen  105 . 
     In some examples, a length of a proximal portion elongate member  114  having a circular cross section as illustrated in  FIG.  3    may be approximately 100 cm to approximately 130 cm, such as approximately 110 cm to approximately 120 cm, or approximately 115 cm or approximately 117.5 cm. In some examples, the tapered portion of elongate member  114  adjacent to the proximal portion and extending to a distal end of elongate member  114  may have a length between approximately 2 cm to approximately 20 cm, such as approximately 10 cm. 
     In some examples, a length of elongate member  114  having a cross section substantially as illustrated along line  4 - 4  may be between approximately 20 mm to approximately 60 mm, such as approximately 40 mm. The cross-section along line  4 - 4  may be selected to enable elongate member  114  to be positioned between at least adjacent portions of inner liner  104  and outer jacket  106  and provide structural support to entry port  109 . 
     In addition, in some examples (which may be combined with the foregoing dimensions), a length of elongate member  114  having a cross-section substantially as illustrated along line  5 - 5  may be between approximately 5 mm to approximately 15 mm, such as approximately 10 mm. The cross-section along line  5 - 5  may be selected to enable elongate member  114  to be positioned between at least adjacent portions of inner liner  104  and outer jacket  106  without obstructing inner lumen  105  of elongate body  102 . In some examples, the distal-most section of elongate member  114  including a distal end of elongate member  114 , e.g., represented by the cross-section shown in  FIG.  5   , may be selected to enable the distal portion of elongate member  114  to be flexible enough to be moved out of the way of a medical device that is being introduced into lumen  105  of elongated body  102  via entry port  109 . As the medical device is pushed into lumen  105 , elongate member  114  may inadvertently wrap around the medical device due to the manner in which it extends through outer catheter  110 . This can be referred to as “wire wrap.” The relatively flexible distal portion of elongate member  114  may enable the medical device to push past any wrapped sections of elongate member  114  and avoid adverse impacts to medical device delivery attributable to wire wrap. 
     In some examples, the cross-section along line  5 - 5  may be selected to substantially match a thickness of anchor member  116 . This provide a smoother profile at the juncture of elongate member  114  and anchor member  116 , which may result in a smoother profile of entry port  109  and lumen  105 . 
     In some examples, a cross-section of elongate member  114  may be flat or substantially flat on one side (such as D-shaped) or on both sides at a portion that is distal to a portion having a circular cross section. A cross-section of elongate member  114  may have any suitable size and/or shape according to particular needs. In addition, elongate member  114  may be tapered using nay suitable technique. In some examples, the tapered cross-section of elongate member  114  may be defined by an abrasive processing, such as grinding, sanding, or grit blasting. In some examples, the abrasive processing to form the taper of elongate member  114  may form at least one rough surface on elongate member. The at least one rough surface may increase the surface area of elongate member  114 . The increased surface area may improve adhesion of a polymeric material, such as PTFE, and decrease delamination of the polymeric material, for example, during use of catheter  100 . The polymeric material may be, for example, the material used to form inner liner  104  and/or outer jacket  106 . 
     Elongate member  114  being tapered in a distal direction may provide particular advantages in some cases. For example, a proximal portion of elongate member  114  having a solid round profile may have greater cross sectional area and mechanical integrity compared to an elongate member having a different profile, such as a rectangular profile or a hollow profile. In this way, the proximal portion of elongate member  114  may better resist kinking in response to a push force better than an elongate member having a different profile, such as a rectangular cross-section and/or a hollow cross-section. For example, a solid 0.45 mm diameter round profile stainless steel elongate member  114  may transfer at least 400 gram-force. 
     Additionally, or alternatively, due to its D-shaped tapered portions (e.g., alone lines  4 - 4  and  5 - 5 ), elongate member  114  may have greater flexibility at a distal portion (relative to non-D-shaped profiles, such as circular profiles), which may help facilitate navigability of catheter  100  through vasculature of a patient. The D-shaped profile may also enable elongate member  114  to have a similar profile to anchor member  116  at a portion of elongate member  114  bonded to anchor member  116  which may allow push assembly  108  to maintain a smoother profile at the juncture of elongate member  114  and anchor member  116 . This smoother profile at the juncture of elongate member  114  and anchor member  116  may result in a smoother profile of entry port  109  and lumen  105 , which may facilitate easier introduction of medical devices into lumen  105  via entry port  109 . 
       FIG.  6    is a conceptual cross-sectional view of catheter  100  of  FIGS.  1  and  2    taken along line  6 - 6  in  FIG.  2   .  FIG.  6    illustrates a cross-section of inner liner  104 , outer jacket  106 , and elongate member  114  within the section of catheter  100  defining entry port  109 . Inner liner  104  and outer jacket  106  do not define circular cross-sections in the portion of catheter  100  shown in  FIG.  6    because they are configured (e.g., by skiving) to define entry port  109 . In addition, anchor body  116  is not present in the portion of catheter  100  shown in  FIG.  6   . 
       FIGS.  7 A and  7 B  are conceptual cross-sectional views of examples of catheter  100  of  FIGS.  1  and  2    taken along line  7 - 7  in  FIG.  2   , and  FIGS.  8 A and  8 B  are conceptual cross-sectional views of examples of catheter  100  of  FIGS.  1  and  2    taken along line  8 - 8  in  FIG.  2   .  FIGS.  7 A and  8 A  are conceptual cross-sectional views of catheter  100  during assembly of elongate body  102 , after anchor member  116  has been inserted and advanced between inner liner  104  and outer jacket  106 .  FIGS.  7 B and  8 B  are a conceptual cross-sectional view of catheter  100  after assembly of catheter  100 , after anchor member  116  has been inserted and advanced between inner liner  104  and outer jacket  106 , as shown in  FIGS.  7 A and  8 A , respectively, and after heat has been applied to inner liner  104  and outer jacket  106  to reflow material of inner liner  104  and outer jacket  106  around anchor member  116 . 
     As shown in  FIGS.  7 A- 8 B , anchor member  116  may be positioned between outer jacket  106  and inner liner  104  such that anchor member  116  is positioned within outer jacket  106  and at least partially around an outer perimeter of inner liner  104 . In some examples, anchor member  116  may extend about 140 degrees to about 160 degrees around the outer perimeter of inner liner  104 . For example, a widest portion of anchor member  116 , as shown in  FIGS.  7 A and  7 B  may extend about 140 degrees to about 160 degrees around the widest portion of inner liner  104 . For example, in some examples, anchor member  116  may extend about 160 degrees around the outer perimeter of inner liner  104 . 
     Anchor member  116  defines an inner surface  142  and an outer surface  144 , and, in some examples, one or more of inner surface  142  and outer surface  144  may define a substantially semicircular surface but may, in some examples, include surface irregularities (e.g., waves, bumps, or other texturing). Anchor member  116  may have a thickness t AM  measured in a direction perpendicular to longitudinal axis X of catheter  100 . In some examples, thickness t AM  may be about 50 micrometers thick to about 100 micrometers thick, such as about 76.2 micrometers thick or any other size suitable to fit between inner liner  104  and outer jacket  106  while also having suitable strength to secure push assembly  108  to elongate body  102 . As shown in  FIG.  6   , welding material  146  may join elongate member  114  to anchor member  116 , as describe in further detail below with respect to  FIG.  15   . 
     As shown in  FIGS.  7 B and  8 B , in some examples, heat may be applied to inner liner  104  and/or outer jacket  106  to reflow material from inner liner  104  and/or outer jacket  106  around anchor member  116  to bond anchor member  116  between inner liner  104  and outer jacket  106 . Although  FIG.  7 B  shows reflow of material from both inner liner  104  and outer jacket  106 , in some examples, heat may be applied to only one of inner liner  104  and outer jacket  106  and/or material from only one of inner liner  104  and outer jacket  106  may be reflowed around anchor member  116 . Alternatively, or in addition to reflow, other methods may be used to bond anchor member  116  between inner liner  104  and outer jacket  106 . For example, adhesives may be used. Bonding inner liner  104  and/or outer jacket  106  to anchor member  116  may improve the bond between elongate body  102  and push assembly  108  over methods wherein elongate member  114  is bonded directly to inner liner  104  and/or outer jacket  106 , and may thus improve tensile strength, by providing greater surface area for bonding. 
       FIG.  9    is a conceptual perspective view of anchor member  116  of  FIGS.  1 ,  2 ,  6 ,  7 A,  7 B,  8 A, and  8 B .  FIGS.  10 A and  10 B  are conceptual perspective views of push assembly  108  of  FIGS.  1 ,  2 , and  6   . As shown in  FIGS.  9 ,  10 A, and  10 B , anchor member  116  may define a partial-ring shape. As shown in  FIGS.  10 A and  10 B , anchor member  116  may be secured to elongate member  114  to form push assembly  108 . For example, anchor member  116  may be welded to distal end  118  of elongate member  114  as described in further detail below with reference to  FIGS.  14  and  15   . As another example, anchor member  116  may be adhered or otherwise mechanically connected to distal end  118  of elongate member  114 . 
     In some examples, anchor member  116  may be formed of a radiopaque material such that anchor member  116  may serve as a radiopaque marker to indicate a location of entry port  109  to lumen  105  of elongate body  102 . In other cases, a band may be added to anchor member  116  to serve as a marker. As discussed above, because anchor member  116  is not circular in cross-section, a radiopaque anchor member  116  may help indicate a rotational orientation of catheter  100  (e.g., a rotational orientation of entry port  109 ) within vasculature of a patient. In contrast, an anchor member having a circular cross-section would not indicate the rotational position of entry port  109  of catheter  100 , as the rotational position of the anchor member within a medical image would not appear to change based on the rotational orientation of entry port  109  about longitudinal axis X. 
       FIG.  11    is a conceptual perspective view of an example push assembly  152 , such as push assembly  108  of  FIGS.  1 ,  2 ,  10 A and  10 B , further including a radiopaque band  154 . 
     Push assembly  152  may include anchor member  156  and elongate member  158 . In some examples, anchor member  156  may include one or more radiopaque bands  154  to facilitate visualization of anchor member  156 . 
     Band  154  may be formed from a radiopaque material and can include, for example, a radiopaque marker band (e.g., one or more partial rings) attached to anchor member  158 , e.g., by an adhesive or weld. In some examples, band  154  may include any suitable radiopaque material. In addition to, or instead of a radiopaque marker band, band  154  may include one or more grooves protruding from an outer surface  160  of anchor member  158  or defined by and recessed within outer surface  160  of anchor member  158 . Although band  154  is shown along an outer diameter of anchor member  158 , band  154  may include grooves including, for example, a series of tangential arcs along an inner diameter of anchor member  158  and may be formed from a radiopaque material, or may be filled with a radiopaque material in the case of recessed grooves, which may be visible within the patient with the aid of suitable medical imaging equipment. Band  154  may help a clinician determine an orientation and/or location of anchor member  158  and/or any suitable component of the device described herein. 
       FIGS.  12  and  13    are conceptual cross-sectional views of example anchor members, such as anchor member  116  of  FIGS.  1  and  2   , with an inner and/or outer surface defining a non-semicircular surface. For example, as shown in  FIG.  12   , anchor member  172  may define inner surface  174  and outer surface  176 , and one or more of inner surface  174  and outer surface  176  may define a non-semicircular surface. For example, outer surface  176  may define a plurality of notches  178   a - 178   n . As another example, as shown in  FIG.  13   , anchor member  182  may define inner surface  184  and outer surface  186  and one or more of inner surface  184  and outer surface  186  may define a plurality of waves  188   a - 188   n . In some examples, as in  FIG.  12   , both inner surface  174  and outer surface  176  may define a non-semicircular surface. In other examples, as in  FIG.  12   , only one of inner surface  174  and outer surface  176  may define a substantially non-semicircular surface. 
     Although  FIGS.  12  and  13    show particular example anchor members  172  and  182  with non-semicircular and substantially semicircular surfaces, any suitable surfaces may be used according to particular needs. For example, an anchor member may define inner and outer surfaces both defining a plurality of waves. As another example, only one of an inner surface and an outer surface of an example anchor member may define a plurality of notches. In some examples, an anchor member may include one of an inner surface and an outer surface defining a plurality of notches and another of the inner surface and outer surface defining a plurality of waves. An anchor member may have any suitable combination of inner and outer surfaces according to particular needs. 
     In some examples, an anchor member with inner and/or outer surfaces defining non-semicircular surfaces may provide particular advantages. For example, such non-semicircular advantages may increase surface area of the surface(s) and thus improve bond between the anchor member and the inner liner, and/or the outer jacket. For example, reflow of inner liner and/or outer jacket material may bond with a greater surface area of the anchor member and may thus improve the bond between the inner liner and/or outer jacket and the anchor member. 
     Anchor member  116  may be mechanically connected to elongate member  114  using any suitable technique, such as, but not limited to, welding, an adhesive, or mechanical fixation mechanism, such as a strap, or the like.  FIG.  14    is a conceptual side view of an example of anchor member  116  of push assembly  108  of  FIGS.  2 ,  10 A, and  10 B  and a distal portion of elongate member  114  of the push assembly  108  of  FIGS.  2 ,  10 A, and  10 B , before anchor member  116  and elongate member  114  are mechanically connected together to form push assembly  108 .  FIG.  15    is a conceptual side view of push assembly  108  of  FIG.  14    after anchor member  116  and elongate member  114  are mechanically connected together to form push assembly  108 . 
     As shown in  FIG.  14   , anchor member  116  may extend from a proximal end  192  to a distal end  128 . Length L AM  of anchor member  116  may be measured along axis X (where orthogonal x-y axes are shown in  FIGS.  14  and  15    for ease of description only) from proximal end  192  to distal end  128  of anchor member  116 . In some examples, length L AM  of anchor member  116  is about 2 mm to about 5 mm, such as about 3 mm. Anchor  116  may have other lengths in other examples. Anchor member  116  may define a slot  194  extending from proximal end  192  towards distal end  128 . In some examples, distal end  128  of elongate member  114  may be positioned at least partially within slot  194 . In some examples, slot  194  has a length L S  from about 25 percent to about 75 percent of a length L AM  of anchor member  116 . In some examples, length L S  of slot  194  may be about 40 percent to about 60 percent of length L AM  of anchor member  116 . In some examples, anchor member  116  may be welded to elongate member  114 . For example, as shown in  FIG.  15   , welding material  146  may be placed within slot  194  and between anchor member  116  and elongate member  114 . In some examples, slot  194  may extend through the entire thickness t AM  of anchor member  116 . In other examples, slot  194  may extend only partially through thickness t AM  of anchor member  116 . Slot  194  may extend a thickness sufficient to receive distal end  118  of elongate member  114  and welding material  146 . 
     Anchor member  116  defining a slot  194  within which distal end  118  of elongate member  114  and welding material  146  may be placed in order to bond distal end  118  of elongate member  114  to anchor member  116  may provide one or more advantages. For example, slot  194  may increase the surface area of the portions of elongate member  114  and anchor member  116  that are mechanically connected to each other, which may increase the strength of the mechanical connection between elongate member  114  and anchor member  116 . As another example, slot  194  may provide for a lower radial profile of push assembly  108  compared to examples in which an anchor member does not include a slot or in which a slot is not wide enough for both distal end  118  of elongate member  114  and welding material  146  because distal end  118  and/or welding material  146  need not increase a radial profile of elongate body  102  and/or push assembly  108  by extending radially, inwardly or outwardly, from anchor member  116 . This may also provide improved assembly of catheter  100  by providing a less bulky push assembly  108  that may be more easily inserted and advanced between inner liner  104  and outer jacket  106 . 
       FIG.  16    is a conceptual perspective view of a portion of an example elongate member  114  of  FIGS.  1 ,  2 ,  10 A,  10 B, and  11   . In some examples, a sleeve  202  may surround at least a portion of elongate member  114 . In some examples, a sleeve  202  may surround at least a portion of elongate member  114  external to lumen  105  defined by elongate body. Sleeve  202  may include one or more layers of material configured to surround at least a portion of elongate member  114  and to distinguish elongate member  114  from other medical devices and/or to enable easier grip of elongate member  114   
     In some examples, sleeve  202  may be textured such that it defines at least one textured surface, which may help a clinician grip sleeve  202  and/or sleeve  202  grip elongate member  114 . For example, in some examples, sleeve  202  may be etched such that it defines at least one etched surface. As another example, sleeve  202  may define ridges, grooves, or the like on the surface facing outward (the surface that a clinician would grip when engaging sleeve  202 ), and/or on the surface facing elongate member  114 . 
     In addition to, or instead of, aiding a clinician&#39;s handling of elongate member  114 , in some examples, sleeve  202  may provide one or more visible indicia that help differentiate elongate member  114  from other medical devices. For example, sleeve  202  may be a different color than at least one of elongate member  114 , inner liner  104 , and outer jacket  106 . In addition, or instead, sleeve  202  may include one or more visible and/or tactile bands  204 . In some examples, bands  204  may include a partial cut around a perimeter of sleeve  202 . In some examples, the partial cut may extend only partially through a radial thickness is of sleeve  202 . In some examples, the partial cut may extend 360 degrees around a perimeter of sleeve  202 . Bands  204  may include a double-stripe mark. Bands  204  may include a marker with any suitable visual characteristics, such as, but not limited to, a particular color(s), visible pattern(s), and/or texture(s). 
     Sleeve  202  may provide particular advantages. For example, sleeve  202  including a textured surface, having a distinct color, having bands  204  and/or or other visually distinct indicium or indicia may help to tactilely and/or visually distinguish elongate member  114  from other components including, for example, a guidewire or other catheters or devices used with catheter  100  such that a user may more easily distinguish it from other components. For example, without sleeve  202 , elongate member  114  may look and/or feel like a guidewire and may be difficult to identify as being a part of push assembly  108 . 
       FIG.  17    is a flowchart illustrating an example method including the various stages of assembly of example catheter  100  shown in  FIGS.  1  and  2   . In accordance with this method of assembly, anchor member  116  of push assembly  108  is inserted between inner liner  104  and outer jacket  106  of catheter  100  such that, after insertion, anchor member  116  extends only partially around an outer perimeter of inner liner  104  ( 212 ). In some examples, anchor member  116  is advanced between inner liner  104  and outer jacket  106  in a distal direction ( 214 ). In some examples, anchor member  116  may be advanced between inner liner  104  and outer jacket  106  in a distal direction until proximal end  192  of anchor member  116  is aligned with proximal end  138  of entry port  109 . In other examples, anchor member  116  may be advanced between inner liner  104  and outer jacket  106  in a distal direction until distal end  128  of anchor member  116  is aligned with distal end  140  of entry port  109 . Anchor member  116  may be advanced to any suitable position between inner liner  104  and outer jacket  106  according to particular needs. 
     After insertion and advancement of anchor member  116 , distal to proximal end  10  of elongate body  102 , a portion of push assembly  108 , including anchor member  116 , is positioned between adjacent portions inner liner  104  and outer jacket  106  and, proximal end  10  of elongate body  102 , a portion of push assembly  108  is positioned outside of outer jacket  106  and inner liner  104 . 
     In some examples, heat may be applied to inner liner  104  and/or outer jacket  106  to reflow material around anchor member  116  ( 214 ). 
     In some examples, a method of assembly may further include abrasive processing of elongate member  114  to form a taper, such as the D-shaped taper illustrated in  FIGS.  4  and  5   . The abrasive processing may include, for example, grinding, sanding, or grit blasting at least a portion of elongate member  114  to remove material. 
     In some examples, a method of assembly may further include coupling anchor member  116  to elongate member  114 . For example, anchor member  116  may be coupled to elongate member  114  before insertion of anchor member  116  between inner liner  104  and outer jacket  106  of catheter  100 . In some examples, coupling anchor member  116  to elongate member  114  may include positioning distal end  118  of elongate member  114  at least partially within slot  194  of anchor member  116 . In some examples, coupling anchor member  116  to elongate member  114  may include welding anchor member  116  to elongate member  114 . In some examples, welding anchor member  116  to elongate member  114  may include placing welding material  146  within slot  194  and between anchor member  116  and elongate member  114 . 
     In some examples, the method may further include positioning reinforcement member  126  between at least a portion of inner liner  104  and at least a portion of outer jacket  106 . In some examples, the method may include positioning distal end  128  of anchor member  116  proximal to reinforcement member  126 . In some examples, the method may include positioning distal end  128  of anchor member  116  such that it abuts proximal end  130  of reinforcement member  126 . In some examples, the method may include positioning sleeve  202  around at least a portion of elongate member  114 . 
     Various examples have been described. These and other examples are within the scope of the following claims.