A catheter comprising a surface treated structural support member

Abstract

In some examples, a catheter includes an inner liner, an outer jacket, and a structural support member positioned between at least a portion of the inner liner and at least a portion of the outer jacket. A surface of at least a portion of the structural support member is surface treated to increase adhesion of the surface to at least one of the inner liner or the outer jacket. Example surface treatments include physical treatments, chemical treatments, coating treatments, and combinations thereof. In some cases, the at least a portion of the structural support member is a relatively high density portion.

Description

Technical Field

[0001] This disclosure relates to medical catheters and methods of manufacturing them. Background Technology

[0002] Medical catheters with at least one lumen have been proposed for use in a variety of medical procedures. For example, in some cases, medical catheters can be used to access and treat defects in blood vessels, such as, but not limited to, lesions or occlusions in the blood vessels. Summary of the Invention

[0003] In some aspects, this disclosure describes example conduits with increased adhesion between structural support members (such as coils or braids) and inner and / or outer sheaths, as well as methods of forming conduits.

[0004] In some examples described herein, a conduit includes an inner liner, an outer sheath, and a structural support member positioned between at least a portion of the inner liner and at least a portion of the outer sheath. Prior to conduit formation, the structural support member is surface-treated by applying a surface treatment to at least a portion of the surfaces of the structural support member (e.g., an inner radial surface and / or an outer radial surface). As a result of one or more of these surface treatments, the surfaces of the structural support member exhibit increased adhesion to the inner liner and / or the outer sheath. Surface treatments may include physical treatments, such as roughening to increase the roughness and / or surface area of ​​the structural support member; chemical treatments, such as functionalization to increase charge or generate reactive portions on the structural support member; coating treatments, such as coating applications that add reactive portions to the structural support member; or any combination of physical treatments, chemical treatments, coating treatments, or other treatments.

[0005] In some instances, surface treatments may be applied to specific portions of the structural support member or in varying amounts to selectively enhance portions of the structural support member that may be relatively prone to displacement within the catheter (e.g., higher-density portions of the structural support member). In these various ways, the catheters described herein may exhibit increased adhesion between the surface-treated structural support member and the inner liner and / or outer sheath compared to catheters that do not contain a surface-treated structural support member.

[0006] Clause 1: In some instances, a catheter includes an inner liner, an outer sheath, and a structural support member positioned between at least a portion of the inner liner and at least a portion of the outer sheath, wherein at least a portion of the surface of the structural support member is surface-treated to increase adhesion of the surface to at least one of the inner liner or the outer sheath.

[0007] Clause 2: In some examples of the conduit described in Clause 1, the structural support member is surface-treated on its inner radial surface but not on its outer radial surface.

[0008] Clause 3: In some examples of the conduit described in Clause 1, the structural support member is surface-treated on its outer radial surface but not on its inner radial surface.

[0009] Clause 4: In some examples of the conduit according to any one of Clauses 1 to 3, the surface roughness of the surface of at least a portion of the structural support member is greater than about 2 micrometers Ra.

[0010] Clause 5: In some examples of the catheter according to any one of Clauses 1 to 3, the surface of at least a portion of the structural support member is covalently bonded to at least one of the inner liner or the outer sheath.

[0011] Clause 6: In some examples of the catheter according to any one of Clauses 1 to 3, the surface of at least a portion of the structural support member includes a coating covalently bonded to at least one of the inner liner or the outer sheath.

[0012] Clause 7: In some examples of the conduit according to any one of Clauses 1 to 3, the structural support member includes a coiled structural support member.

[0013] Clause 8: In some examples of the conduit described in Clause 7, a first portion of the coiled structure support member has a first coil pitch, and a second portion of the coiled structure support member has a second coil pitch smaller than the first coil pitch.

[0014] Clause 9: In some examples of the conduit described in Clause 8, the surface treated includes a first surface of the first portion of the coiled structure support member, and wherein the second surface of the second portion of the coiled structure support member is not surface treated.

[0015] Clause 10: In some instances of the conduit described in Clause 8 or 9, the surface treated includes a first surface of the first portion of the coiled structure support member having a first surface roughness, and wherein the second surface of the second portion of the coiled structure support member has a second surface roughness less than the first surface roughness.

[0016] Clause 11: In some examples of the conduit according to any one of Clauses 8 to 10, the shear strength of said first portion is greater than about twice the shear strength of the structural support member without surface treatment.

[0017] Clause 12: In some examples of the conduit described in Clause 7, a first portion of the coiled structure support member has a first diameter, and a second portion of the coiled structure support member has a second diameter greater than the first diameter.

[0018] Clause 13: In some examples of the conduit according to any one of Clauses 1 to 3, the structural support member includes a braided structural support member.

[0019] Clause 14: In one example, a catheter includes an inner liner, an outer sheath, a support layer, and a structural support member, the support layer being positioned between at least a portion of the inner liner and at least a portion of the outer sheath, the structural support member being positioned between at least a portion of the inner liner and at least a portion of the outer sheath, wherein at least a portion of the surface of the structural support member is surface-treated to increase adhesion of the surface to at least one of the inner liner, the outer sheath, or the support layer.

[0020] Clause 15: In some instances of the catheter described in accordance with Clause 14, at least a portion of the support layer is positioned between the structural support member and the outer sheath.

[0021] Clause 16: In some instances of the catheters described in accordance with Clause 14 or 15, the surface of at least a portion of the structural support member is covalently bonded to at least one of the inner liner, the outer sheath, or the support layer.

[0022] Clause 17: In some instances of the catheters described in accordance with Clause 14 or 15, the surface of at least a portion of the structural support member includes a coating covalently bonded to at least one of the inner liner, the outer sheath, or the support layer.

[0023] Clause 18: In some examples of the catheter according to any one of Clauses 14 to 17, the structural support member includes a coiled structural support member, and a first portion of the coiled structural support member has a first coil pitch, and a second portion of the coiled structural support member has a second coil pitch smaller than the first coil pitch.

[0024] Clause 19: In some examples of the conduit described in Clause 18, the surface treated includes a first surface of the first portion of the coiled structure support member, and wherein the second surface of the second portion of the coiled structure support member is not surface treated.

[0025] Clause 20: In some examples of the conduit described in Clause 18 or 19, the surface treated includes a first surface of the first portion of the coiled structure support member having a first surface roughness, and a second surface of the second portion of the coiled structure support member having a second surface roughness less than the first surface roughness.

[0026] Clause 21: In one instance, a method of manufacturing a conduit comprises: applying a surface treatment to at least a portion of the surface of a structural support member; positioning the structural support member around an inner liner; and positioning an outer sheath around the structural support member and the inner liner.

[0027] Clause 22: In some instances of the method described in accordance with Clause 21, applying a surface treatment includes applying the surface treatment to the inner radial surface of the structural support member, while substantially not applying the surface treatment to the outer radial surface of the structural support member.

[0028] Clause 23: In some instances of the method described in accordance with Clause 21, applying a surface treatment includes applying the surface treatment to the outer radial surface of the structural support member, while substantially not applying the surface treatment to the inner radial surface of the structural support member.

[0029] Clause 24: In some instances of the method according to any one of Clauses 21 to 23, applying surface treatment includes roughening the surface of at least a portion of the structural support member to increase the surface roughness of the surface.

[0030] Clause 25: In some instances of the method described in accordance with Clause 24, the surface roughness of the surface of at least a portion of the structural support member is greater than about 2 micrometers Ra.

[0031] Clause 26: In some instances of the method according to any one of Clauses 21 to 23, applying a surface treatment includes chemically treating at least a portion of the surface of the structural support member to increase the surface charge.

[0032] Clause 27: In some instances of the method according to any one of Clauses 21 to 23, applying surface treatment includes chemically treating at least a portion of the surface of the structural support member to functionalize the surface with a reactive component.

[0033] Clause 28: In some instances of the method according to any one of Clauses 21 to 23, the surface treatment comprises coating at least a portion of the surface of the structural support member with a reactive layer having a reactive portion.

[0034] Clause 29: In some instances of the method according to any one of Clauses 21 to 23, the structural support member comprises a coiled structural support member.

[0035] Clause 30: In some instances of the method described in accordance with Clause 29, a first portion of the coiled structure support member has a first coil pitch, and a second portion of the coiled structure support member has a second coil pitch smaller than the first coil pitch.

[0036] Clause 31: In some instances of the method described in accordance with Clause 30, applying a surface treatment includes applying the surface treatment to a first surface of the first portion of the coiled structural support member and avoiding applying a second surface treatment to a second surface of the second portion of the coiled structural support member.

[0037] Clause 32: In some instances of the method described in accordance with Clause 30, applying surface treatment includes roughening a first surface of the first portion of the coiled structure support member to a first surface roughness, and roughening a second surface of the second portion of the coiled structure support member to a second surface roughness less than the first surface roughness.

[0038] Clause 33: In some instances of the method described in accordance with Clause 30, applying a surface treatment includes chemically treating the first portion of the coiled structure support member to a first charge and chemically treating the second portion of the coiled structure support member to a second charge less than the first charge.

[0039] Clause 34: In some instances of the method described in accordance with Clause 29, a first portion of the coiled structural support member has a first diameter, and a second portion of the coiled structural support member has a second diameter greater than the first diameter.

[0040] Clause 35: In some instances of the method described in accordance with Clause 21, the structural support member comprises a woven structural support member.

[0041] The examples described in this article can be combined in any permutation or combination.

[0042] Details of one or more aspects of this disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the technology described in this disclosure will become apparent from the description and drawings and from the claims. Attached Figure Description

[0043] Figure 1 This is a side view of an example duct that includes the duct body and hub.

[0044] Figure 2 yes Figure 1 A conceptual cross-sectional view of a portion of the catheter body, wherein the cross-section is taken through the center of the catheter body and along the longitudinal axis of the catheter body.

[0045] Figure 3 It is a conceptual cross-sectional view of a portion of the catheter body, including the coiled structural support members, wherein the cross-section is taken through the center of the catheter body and along the longitudinal axis of the catheter body.

[0046] Figure 4 It is a conceptual cross-sectional view of a portion of the catheter body containing braided structural support members, wherein the cross-section is taken through the center of the catheter body and along the longitudinal axis of the catheter body.

[0047] Figure 5A It is a conceptual cross-sectional view of a portion of the catheter body containing a tapered structural support member, wherein the cross-section is taken through the center of the catheter body and along the longitudinal axis of the catheter body.

[0048] Figure 5B yes Figure 5A Along the main body of the catheter Figure 5A The conceptual cross-sectional view taken by line AA in the middle.

[0049] Figure 5C yes Figure 5A Along the main body of the catheter Figure 5A The conceptual cross-sectional view taken from line BB in the middle.

[0050] Figure 6 It is formed Figure 1-5C A flowchart of an example method for constructing a catheter.

[0051] Figure 7 It is formed Figure 1-5C A flowchart of an example method for constructing a catheter. Detailed Implementation

[0052] This disclosure describes a catheter comprising a relatively flexible catheter body with increased structural integrity, the catheter body being configured to be guided through a patient's vascular system. The catheter can be used to diagnose and treat a variety of conditions, including thrombosis. Thrombosis occurs, for example, when a thrombus (e.g., a blood clot or other embolus) forms and obstructs a patient's vascular system. In some medical procedures, to treat a patient with thrombosis, a clinician may position an aspiration catheter in the patient's blood vessel (i.e., catheter insertion) near the thrombus, apply suction to the aspiration catheter, and engage the thrombus with the tip of the aspiration catheter. Such a medical procedure can be, for example, direct aspiration first-pass technique (ADAPT) used for acute stroke thrombectomy or any other aspiration of thrombi or other substances from the neurovascular system or other blood vessels.

[0053] In addition to or as a substitute for medical aspiration, catheters can be used to deliver therapeutic devices to target treatment sites within a patient's vascular system (e.g., the neurovascular system) to treat defects in the vascular system, such as, but not limited to, aneurysms or arteriovenous malformations. Therapeutic neurovascular devices can comprise any suitable medical device configured to treat defects in a patient's vascular system or to facilitate treatment of the neurovascular system. For example, therapeutic devices can include thrombectomy devices, shunts, stents, aspiration catheters, drug delivery catheters, balloon catheters, microvascular plugs, filters, embolization retrieval devices (e.g., stent retrieval devices or aspiration catheters), or implantable medical devices such as embolization coils.

[0054] To position the catheter within a patient's blood vessel, a clinician may push the proximal portion of the catheter (e.g., the proximal end) to advance the catheter through the vessel. The vessel wall may guide the distal tip of the catheter (e.g., at the distal end) through the vessel. However, some vessels, such as cerebral arteries, have tortuous configurations. These tortuous configurations may include bends of relatively small radius that cause the catheter to bend sharply or create resistance along the longitudinal axis of the catheter. As discussed in further detail below, the catheters described herein enable the catheter to be guided to a target site within the patient's vascular system with relatively high structural integrity, for example, by increasing the adhesion between the structural support members and the outer sheath and / or inner liner and / or by using increased density (e.g., pitch or braid density, which can be expressed in weft per inch) of the structural support members to support transition segments in the segmented outer sheath. Therefore, the catheters described herein can be stabilized (e.g., resist delamination between the structural support members and the outer sheath and / or inner liner) and / or resist buckling within the segmented outer sheath.

[0055] In some of the examples described herein, the catheter includes a structural support member positioned between an inner liner and an outer sheath. Prior to or during catheter assembly, the structural support member can be surface-treated by applying a surface treatment to the overall surface or at least a portion of the structural support member (e.g., an inner radial surface and / or an outer radial surface). Some surface treatments may include physical processes, such as roughening, to increase the roughness and / or surface area of ​​the structural support member in contact with the outer sheath, inner liner, and / or support layer. Some surface treatments may include chemical processes, such as functionalization or coating, to increase charge or generate reactive portions on the structural support member to bond with the outer sheath, inner liner, and / or support layer. Surface-treated structural support members can adhere more firmly and / or more easily, directly or through an intermediate support layer, to the outer sheath and / or inner liner, making them less likely to separate from the outer sheath and / or inner liner in response to compressive or bending forces experienced by the catheter as it traverses the vascular system, compared to catheters without surface-treated structural support members.

[0056] In some instances, surface treatments can be applied to specific portions of the structural support member, or in varying amounts, to increase adhesion between those portions and the inner liner and / or outer sheath. Certain portions of the structural support member may experience separation from the inner liner and / or outer sheath more likely than other portions of the conduit, such as due to relatively higher forces or deformations experienced at these portions, or reduced coil-to-coil or braid-to-coil contact between the inner liner and outer sheath at these portions. For example, higher density or diameter sections of the structural support member during outer sheath formation can reduce the flow of outer sheath material between the structural support member's structures (e.g., coils) (e.g., during heat shrinkage of the outer sheath material or during reflow processes). This reduced flow, whether directly (e.g., in a three-layer conduit design) or through the support layers (e.g., in a four-layer conduit design), can lead to reduced contact between the inner liner and outer sheath. Surface treatments can be applied to the structural support member to at least partially compensate for the smaller contact area between the inner liner and outer sheath.

[0057] In the examples described herein, the catheter comprises an inner liner, an outer sheath comprising multiple outer sheath segments, and a structural support member positioned between at least a portion of the inner liner and the outer sheath. Each outer sheath segment is longitudinally adjacent to another outer sheath segment and may have different compositions or properties, such as different materials (e.g., different chemical compositions), different durometers, and / or different thicknesses. Due to the structural discontinuities and / or different compositions or properties of adjacent outer sheath segments, the junction between adjacent outer sheath segments may be a relatively weak point where catheter buckling or collapse is more likely to occur. To strengthen the junction, the structural support member has a variable density near the junction that is relatively higher than the density at other parts of the structural support member (e.g., higher coil pitch or more weft per inch in the case of braiding). For example, the middle segment of the structural support member aligned longitudinally with the junction between two outer sheath segments may have a relatively high density compared to adjacent segments of the structural support member proximal and distal to the middle segment. The relatively high-density section can resist compression at the junction between two outer sheath sections, making the structural support members less likely to kink or collapse at the junction in response to compressive or bending forces experienced by the guide catheter as it passes through the vascular system, compared to a catheter with a relatively high-density section that does not contain structural support members at the junction between two adjacent outer sheath sections.

[0058] In various ways described herein, example catheters can resist temporary (e.g., flexion) or permanent (e.g., delamination) deformation when guided through vascular systems with tortuous configurations. Figure 1 This is a side view of an example catheter 10 including the catheter body 12 and hub 14. The catheter hub 14 is located at the proximal end of the catheter 10 and defines the inner lumen 26 through which access to the catheter body 12 is possible. Figure 2 (As shown in the diagram) and in some instances, closed openings. For example, the catheter hub 14 may include a Luer connector, a hemostatic valve, or another mechanism or combination of mechanisms for connection to another device. In some instances, the catheter 10 includes a strain relief member 11, which may be part of the hub 14 or may be detachable from the hub 14. In other instances, the proximal end of the catheter 10 may include an alternative structure to or in place of the hub 14.

[0059] The catheter body 12 is an elongated body extending from a proximal end 12A to a distal end 12B and defining at least one inner lumen 26 (e.g., one, two, or three inner lumens) terminating at a distal opening 13 defined by the catheter body 12. Figure 1In the example shown, the proximal end 12A of the catheter body 12 is housed within a hub 14 and is mechanically or otherwise attached to the hub 14 by adhesive, welding, or other suitable techniques or combinations thereof. An opening 15 defined by the hub 14 and located at the proximal end 14A of the hub 14 is aligned with the inner lumen 26 of the catheter body 12, allowing the inner lumen 26 of the catheter body 12 to enter through the opening 15.

[0060] The catheter body 12 has a suitable length for entry into the target tissue site within the patient's body from the vascular entry point. The length can be measured along the longitudinal axis 16 of the catheter body 12. The target tissue site can depend on the medical procedure using the catheter 10. For example, if the catheter 10 is intended to enter the distal vascular system in the patient's brain from the femoral artery entry point in the patient's groin, the length of the catheter body 12 can be approximately 129 cm to approximately 135 cm, such as approximately 132 cm, but other lengths can be used. In other instances, such as where the catheter 10 is intended to enter the distal vascular system in the patient's brain from the radial artery entry point, the length of the catheter body 12 can be approximately 80 cm to approximately 120 cm, such as approximately 85 cm, 90 cm, 95 cm, 100 cm, or 105 cm, but other lengths can be used (e.g., a sheathed or radial intermediate catheter can be 5-8 cm long).

[0061] The catheter body 12 can be relatively thin-walled, such that for a given outer diameter, it defines a relatively large inner diameter, which can further contribute to the flexibility and kink resistance of the catheter body 12. The wall thickness of the catheter body 12 can be the difference between the outer diameter and the inner diameter of the catheter body 12 as defined by the inner lumen 26. For example, in some instances, the outer diameter of the catheter body 12 can be from about 4 Frenchies to about 12 Frenchies, such as about 5 Frenchies or about 6 Frenchies. The measurement term Frenchie (abbreviated as Fr or F) is three times the diameter of the device as measured in mm. Thus, a diameter of 6 Frenchies is about 2 millimeters (mm), a diameter of 5 Frenchies is about 1.67 mm, a diameter of 4 Frenchies is about 1.33 mm, and a diameter of 3 Frenchies is about 1 mm. The terms “about” or “approximately” as used herein with respect to dimensions can refer to an exact value or within a range of 1%, 5%, or 10% of the value resulting from manufacturing tolerances. For example, a length of about 10 mm refers to a length of 10 mm within the limits of manufacturing tolerances, or in various instances, a length of 10 mm + / - 0.1 mm, + / - 0.5 mm, or + / - 1 mm.

[0062] In some instances, instead of being formed by two or more discrete and separate longitudinally extending segments mechanically connected to each other, such as at an axial mating joint, the catheter body 12 can be substantially continuous along its length. For example, the catheter body 12 may include an inner lumen 26 defining the catheter body 12 and extending continuously from the proximal end 12A to the distal end 12B of the catheter body 12, and structural support members extending across at least a portion of the proximal portion 17A, at least a portion of the distal portion 17B, and the intermediate portion 17C of the catheter body 12. Compared to a catheter body comprising two or more longitudinally extending segments mechanically connected to each other, a substantially continuous catheter body 12 can be configured to better distribute forces in the longitudinal direction (along the longitudinal axis 16) and in the rotational direction (rotation about the longitudinal axis 16). Therefore, the substantially continuous construction of the catheter body 12 can facilitate the transmission of axial thrust from the proximal portion 17A to the distal portion 17B of the catheter body 12, and the transmission of rotational force (if any) applied from the proximal portion 17A to the distal portion 17B. Although in some instances, as will be referenced... Figure 3 and 4 As described, the catheter body 12 includes an outer sheath formed by two or more longitudinally extending segments that are adjacent to each other due to a continuous inner liner and structural support members extending along most of the length of the catheter body 12. Compared to a catheter body that includes two or more longitudinal segments that are mechanically connected to each other, the catheter body 12 can better distribute force and flexibility.

[0063] In some instances, at least a portion of the outer surface of the catheter body 12 includes one or more coatings, such as, but not limited to, antithrombotic coatings, antimicrobial coatings, and / or lubricating coatings that can help reduce in vitro thrombosis. The lubricating coating can be configured to reduce static and / or dynamic friction between the catheter body 12 and patient tissue as the catheter body 12 advances through the vascular system. The lubricating coating can be, for example, a hydrophilic coating. In some instances, the entire working length of the catheter body 12 (from distal end 14B of the hub 14 to distal end 12B) is coated with a hydrophilic coating. In other instances, only a portion of the working length of the catheter body 12 is coated with a hydrophilic coating. This provides a length of catheter body 12 distal to the distal end 14B of the hub 14, which a clinician can use to hold the catheter body 12, for example, to rotate the catheter body 12 or push the catheter body 12 through the vascular system.

[0064] As described further in detail below, the catheter body 12 can be used to access relatively distal locations within a patient's body, such as the MCA in the patient's brain. The MCA, as well as other vascular systems or other relatively distal tissue sites in the brain (e.g., relative to the point of vascular entry), may be relatively difficult to reach with a catheter, at least in part due to the tortuous path (e.g., including relatively sharp twists and / or turns) through the vascular system to reach these tissue sites. The catheter body 12 can be structurally configured to be relatively flexible, maneuverable, and kink-resistant, flexure-resistant, and delamination-resistant, such that when a thrust is applied to a relatively proximal portion of the catheter 10 to advance the catheter body 12 distally through the vascular system, it resists flexure, resists kinking when traversing sharp bends around the vascular system, and / or thus resists delamination and / or delamination when bending sharply around the vascular system. As an example, kinking or flexing may occur when a weakness in the catheter body (such as a transition between different structures or materials) deforms along (e.g., flexing) or away from (e.g., kinking) in response to bending or compressive forces. As another example, delamination can occur when two or more components within the catheter body (such as the inner liner, outer sheath, structural support member, and / or a support layer between any of the inner liner, outer sheath, or structural support member) separate in response to bending or compressive forces. Knotting, buckling, and / or delamination of the catheter body 12 may hinder a clinician's efforts to push the catheter body distally (e.g., through a turn).

[0065] Properties that may at least contribute to the maneuverability, flexibility, and / or integrity of the catheter body 12 are the adhesion between the structural support member and one or both of the outer sheath and the inner liner. At least a portion of the surface of the structural support member may be surface-treated to increase adhesion to at least one of the inner liner or outer sheath, such as directly or through the support layer. In some instances, the surface treatment may include physical treatments, such as roughening the surface of a portion of the structural support member to increase surface roughness; chemical treatments, such as chemically treating the surface of a portion of the structural support member to increase surface charge or functionalize the surface with reactive portions; and coating treatments, such as coating the surface of a portion of the structural support member with a functional layer (e.g., a reactive layer with reactive portions). The surface-treated portion of the structural support member may adhere more easily and / or firmly to the inner liner, outer sheath, and / or support layer, thereby increasing the stability of the structural support member between the inner liner and outer sheath and resisting separation due to compression or bending. This increased adhesion may be particularly useful for portions of the structural support member corresponding to sections of the inner liner or outer sheath that may not adhere as firmly. For example, due to the lower permeability of the intermediate layer (e.g., tethering layer) between the coils or braids of the outer sheath material or structural support member, the higher density sections of a variable density structural support member can have reduced surface contact between the inner liner and the outer sheath.

[0066] Another characteristic that can at least contribute to the maneuverability, flexibility, and / or integrity of the catheter body 12 is the variable density of the longitudinally extending segments of the structural support member relative to the outer sheath. For example, the outer sheath may comprise multiple outer sheath segments, each of which is longitudinally adjacent to another of the multiple outer sheath segments. The connection between two outer sheath segments may be a relatively weak point, more prone to collapse in response to longitudinal forces that may be experienced, such as when the catheter is maneuvered. The structural support member may have increased density near the connection to support and reinforce the connection. For example, a first segment of the structural support member may have a relatively low density, a second segment of the structural support member distal to the first segment may have a relatively high density, and a third segment of the structural support member distal to the second segment may have a relatively low density. To reinforce the connection between two outer sheath segments, a second, higher-density segment of the structural support member may be longitudinally aligned with the connection. Although the compressive strength of the joint may be reduced compared to the adjacent sections of the outer sheath, the higher density sections of the structural support members may have increased compressive strength to reduce buckling and / or kinking at the joint.

[0067] Another characteristic that can at least contribute to the maneuverability, flexibility, and / or integrity of the catheter body 12 is the variable diameter of the structural support member and the variable nature of the outer sheath. For example, the diameter of the distal portion of the coiled structural support member can be smaller than the diameter of the proximal portion. This smaller diameter distal section can have increased flexibility and can allow the thicker outer sheath to have lower apparent stiffness and therefore a more flexible material, while also allowing the catheter to maintain a relatively constant inner diameter of the inner liner and outer diameter of the outer sheath.

[0068] Any properties described herein that may at least contribute to the maneuverability, flexibility, and / or integrity of the catheter body 12 may be used alone or in combination with each other.

[0069] Figure 2 This is a conceptual cross-sectional view of a portion of the catheter body 12, including the distal end 12B, wherein the cross-section is taken along the longitudinal axis 16 through the center of the catheter body 12. Figure 2 As shown in the four-layer configuration, the catheter body 12 includes an inner liner 18, a structural support member 20, a support layer 22, and an outer sheath 24; however, in other instances, the catheter body 12 may not include the support layer 22, as in... Figure 3 and 4 The three-layer configuration shown.

[0070] The inner liner 18 defines an inner lumen 26 of the catheter body 12, extending from the proximal end 12A to the distal end 12B and defining a passage for a distal opening 13 extending from the proximal end 12A to the distal end 12B of the catheter body 12. The inner lumen 26 may be sized to accommodate medical devices (e.g., another catheter, guidewire, embolization protection device, stent, or any combination thereof), therapeutic agents, etc. In some instances, at least the inner surface of the inner liner 18 defining the inner lumen 26 may be lubricated to facilitate the introduction and passage of devices, therapeutic agents, etc., through the inner lumen 26. For example, the material forming the entire inner liner 18 may be lubricated, or the inner liner 18 may be formed of two or more materials, wherein the material defining the inner lumen 26 may be more lubricated than the material intersecting with the structural support member 20 and the support layer 22. In some instances, in addition to being formed of a lubricating material, or instead of being formed of a lubricating material, the inner surface of the inner liner 18 is also coated with a lubricating coating. Examples of materials that can form the inner liner 18 include, but are not limited to, polytetrafluoroethylene (PTFE), fluoropolymers, perfluoroalkoxyalkane (PFA), fluorinated ethylene propylene (FEP), or any combination thereof. For example, the inner liner 18 may be formed of etched PTFE, or may consist substantially of etched PTFE.

[0071] The outer sheath 24 is positioned radially outside the inner liner 18 and the structural support member 20, and in some instances, the outer sheath defines the outer surface of the catheter body 12. While a coating or another material may be applied over the outer surface of the outer sheath 24, the outer sheath 24 can substantially define the shape and size of the outer surface of the catheter body 12. The outer sheath 24, together with the structural support member 20 and the inner liner 18, can be configured to define a catheter body 12 with desired flexibility, kink resistance, and maneuverability characteristics. The outer sheath 24 can have stiffness characteristics that contribute to a desired stiffness distribution of the catheter body 12. For example, the outer sheath 24 can be formed with a decreasing stiffness from the proximal portion 17A to the distal portion 17B of the catheter body 12. In some instances, the outer sheath 24 can be formed of two or more different materials capable of causing the outer sheath 24 to exhibit desired stiffness characteristics, as can be described below. Figure 3 and 4 Further details are provided below.

[0072] The structural support member 20 is configured to increase the structural integrity of the catheter body 12 while allowing it to remain relatively flexible. For example, the structural support member 20 may be configured to help the catheter body 12 substantially maintain its cross-sectional shape, or at least help prevent the catheter body 12 from buckling or kinking as it guides through tortuous anatomical structures. Together with the inner liner 18, the outer sheath 24, and optionally the support layer 22, the structural support member 20 can help distribute both thrust and rotational forces along the length of the catheter body 12, which can help prevent kinking of the body 12 during rotation or buckling of the body 12 when thrust is applied. Therefore, a clinician can apply thrust, rotation, or both to the proximal portion 17A of the catheter body 12, and this force can cause the distal portion 17B of the catheter body 12 to advance distally, rotate, or both, respectively. Figure 2 In the example shown, the structural support member 20 extends only along a portion of the length of the conduit body 12; however, in other examples, the structural support member 20 may extend along the entire length of the conduit body 12.

[0073] In some instances, structural support member 20 comprises a generally tubular braided structure (e.g., as shown in the image). Figure 4 The portion 40 of the conduit body 12 shown), and the coil member defining multiple turns (e.g., as shown in the diagram). Figure 3 The structural support member 20 may be a combination of a braided structure and a coil member, as shown in portion 30 of the catheter body 12. Therefore, while examples of this disclosure may describe the structural support member 20 as a coil, in some other instances, the catheter body described herein may contain a braided structure instead of a coil, or a braided structure other than a coil. For example, the proximal portion of the structural support member 20 may contain a braided structure, and the distal portion of the structural support member 20 may contain a coil member, or vice versa. The structural support member 20 may be made of any suitable material, such as, but not limited to, metals (e.g., nickel-titanium alloys, stainless steel, tungsten, titanium, gold, platinum, palladium, tantalum, silver, or nickel-chromium alloys, cobalt-chromium alloys, etc.), polymers, fibers, or any combination thereof. In some instances, the structural support member 20 may contain one or more metal wires braided or coiled around the inner liner 18. The metal wires may comprise round wires, flat-round wires, flat wires, or any combination thereof.

[0074] Structural support member 20 may be coupled, adhered, and / or mechanically connected to at least a portion of the outer surface of the inner bushing 18 and / or at least a portion of the inner surface of the outer sheath 24. In some instances, structural support member 20 may be directly coupled, adhered, and / or mechanically connected to at least a portion of the outer surface of the inner bushing 18 and / or at least a portion of the inner surface of the outer sheath 24. For example, although Figure 2The conduit 10 shows a four-layer configuration including a support layer 22, but in some instances, such as Figure 3 Part 30 or Figure 4 As shown in section 40, the conduit 10 may comprise a three-layer configuration excluding the support layer 22. In such instances, the inner surface of the outer sheath 24 and the outer surface of the inner liner 18 may be at least partially in direct contact with and / or adhered to each other between the braids or coils of the structural support member 20.

[0075] In other instances, such as Figure 2 As shown, the structural support member 20 can be indirectly connected, adhered to, and / or mechanically connected to at least a portion of the outer surface of the inner liner 18 and / or at least a portion of the inner surface of the outer sheath 24 via the support layer 22. For example, the support layer 22 can be a thermoplastic or thermosetting material, such as a thermosetting polymer and / or thermosetting adhesive. In some instances, the support layer 22 is positioned between the structural support member 20 and the inner liner 18 along its entire length, while in other instances, the support layer 22 is positioned only between a portion of the structural support member 20 and the inner liner 18.

[0076] In example conduits that do not include support layer 22, such as Figure 3 and 4 As shown, the outer sheath 24 can be configured to fill at least a portion (e.g., part or all) of the space between the portions of the structural support member 20, such as the space between the turns of the structural support member 20 or the space defined between the wefts of the braid in an instance where the member 20 is a coil member. In an example conduit including a support layer 22, the support layer 22 can be configured to fill at least a portion of the space between the portions of the structural support member 20.

[0077] In some cases, the presence of the outer sheath 24 and / or support layer 22 between the turns of the structural support member 20 can help adhere the outer sheath 24 and the inner liner 18 to each other and firmly integrate the structural support member 20 into the catheter body 12, so that the structural support member 20 can resist detachment during bending or compression of the catheter 10. For example, at least by minimizing or even eliminating gaps between the turns of the structural support member 20, such as gaps that may be caused by insufficient material flow of the outer sheath 24, the outer sheath 24 and / or support layer 22 can provide a higher contact surface between the inner liner 18 and the outer sheath 24, which may better distribute the thrust or torque force applied to the proximal portion 17A of the catheter body 12 to the distal portion 17B. Alternatively or additionally, minimizing or even eliminating gaps between the turns of the structural support member 20 can provide longitudinal support to the structural support member 20 to secure the structural support member within the catheter body 12.

[0078] In some cases, the presence of the outer sheath 24 and / or support layer 22 between the turns of component 20 can help distribute the flexibility provided by component 20 along the length of component 20, which can help prevent kinking of the conduit body 12. For example, at least by eliminating gaps between the turns of structural support component 20, the outer sheath 24 and / or support layer 22 can transmit flexural movements from structural support component 20 along the length of conduit body 12. In some instances, the thickness of support layer 22 (measured in a direction orthogonal to the longitudinal axis 16) is greater than or equal to the cross-sectional dimension of the conductor forming component 20, such that layer 22 is at least partially positioned between outer sheath 24 and structural support component 20. In other instances, the thickness of support layer 22 is less than or equal to the cross-sectional dimension of the conductor forming structural support component 20, such that support layer 22 is not positioned between outer sheath 24 and structural support component 20.

[0079] In some instances, to enhance adhesion of the structural support member 20 to the inner liner 18 and / or outer sheath 24, at least a portion of the surface of the structural support member 20 is surface-treated. The surface of the surface-treated structural support member 20 may include enhanced surface properties such as roughness, charge, or reactive portions. Compared to similar but untreated surface properties of a structural support member, these surfaces of the structural support member 20 can adhere more firmly or easily to the inner liner 18, support layer 22, and / or outer sheath 24. Therefore, the structural support member 20 can be better integrated into the catheter body 12 and is less likely to shift in response to compressive or bending forces on the catheter 10.

[0080] The increased adhesion of the structural support member 20 to the inner bushing 18, outer sheath 24, and / or support layer 22 can be measured and / or quantified in one or more of a variety of ways, including, but not limited to, shear strength (e.g., the structural support member 20 detaching from the inner bushing 18 and / or outer sheath 24 along the longitudinal axis 16), peel strength (e.g., the structural support member 20 detaching radially from the inner bushing 18 and / or outer sheath 24 from the longitudinal axis 16), etc. In some instances, the structural support member 20 and the inner bushing 18 and / or outer sheath 24 may have increased shear strength compared to a structural support member without surface treatment. In some instances, the shear strength of the structural support member 20 may be greater than or equal to approximately twice the shear strength of a similar structural support member without surface treatment.

[0081] In some instances, surface treatment may include physical treatments. Physical treatments include any treatment that results in an increase in the contact area of ​​the surfaces of the structural support member 20 for bonding with the inner layer 18, the outer sheath 24, and / or the support layer 22, or an increase in the mechanical interlock between the surface of the structural support member 20 and the inner sheath 18, the outer sheath 24, and / or the support layer 22. For example, physical treatments may increase the surface area or surface deviation (e.g., tilt angle) of the surface of the structural support member 20. Example physical treatments that may be used include, but are not limited to, mechanical roughening, laser roughening, abrasion, and combinations thereof.

[0082] In some instances, surface treatment may involve roughening the surface of a portion of the structural support member 20, such that said portion of the structural support member 20 may have increased surface roughness. The increased surface roughness may be, for example, an increased contact area, contact slope, and / or fractal nature between the surface of the structural support member 20 and the inner bushing 18, outer sheath 24, and / or support layer 22, thereby increasing adhesion between the structural support member 20 and the inner bushing 18, outer sheath 24, and / or support layer 22. In some instances, at least a portion of the surface of the structural support member 20 contains a surface roughness greater than about 2 micrometers Ra (arithmetic mean deviation of the profile) and / or about 100 micrometers Rz (maximum height of the profile).

[0083] In some instances, surface treatment may include chemical treatment. Chemical treatment includes any treatment that results in an increase in chemical bonding between the structural support member 20 and the inner liner 18, outer sheath 24, and / or support layer 22. For example, chemical treatment may increase the charge or reactivity of the surface of the structural support member 20 to increase intermolecular forces (e.g., van der Waals forces, hydrogen bonds, ionic bonds, and / or covalent bonds) between the structural support member 20 and the inner liner 18, outer sheath 24, and / or support layer 22. One or more of a variety of chemical treatments may be used, including, but not limited to, alkali treatment, acid treatment, ionization, protonation, deprotonation, electric field charge, and combinations thereof.

[0084] In some instances, the surface treatment may involve chemically treating a portion of the surface of the structural support member 20 such that the portion of the structural support member 20 may have an increased surface charge. This increased surface charge may be opposite to the charge of the inner liner 18, the outer sheath 24, and / or the support layer 22, thereby increasing the electrostatic attraction between the structural support member 20 and the inner liner 18, the outer sheath 24, and / or the support layer 22. For example, the structural support member 20 may contain a positive charge, while the outer sheath 24 may contain a negative charge, such that the structural support member 20 and the outer sheath 24 may electrostatically attract each other.

[0085] In some instances, surface treatment may involve chemically treating a portion of the surface of the structural support member 20 such that said portion of the structural support member can be functionalized with reactive portions. For example, the surface of the structural support member 20 may react with an acid or base to produce reactive portions, such as amines, carboxylic acids, or other reactive groups configured to react with a polymer. The inner liner 18, the outer sheath 24, and / or the support layer 22 may comprise a polymer containing various functional groups capable of reacting with the reactive portions on the structural support member 20. The reactive portions on the structural support layer may be bonded (e.g., covalently) to the functional groups of the inner liner 18, the outer sheath 24, and / or the support layer 22. Thus, at least a portion of the surface of the structural support member 20 may be covalently bonded to at least one of the inner liner 18 or the outer sheath 24.

[0086] In some instances, surface treatment may include coating treatments, such as coating a portion of the surface of the structural support member 20 with a functional layer (e.g., a reactive layer having reactive portions). The functional layer may provide the roughness, charge, and / or reactive properties described above with respect to physical or chemical treatments, rather than providing surface properties through direct surface treatment of the structural support member 20. For example, the surface of the structural support member 20 may comprise a polymer coating containing reactive portions configured to react with functional groups of the inner liner 18, the outer sheath 24, and / or the support layer 22. Thus, at least a portion of the surface of the structural support member 20 may comprise a coating covalently bonded to at least one of the inner liner 18 or the outer sheath 24.

[0087] In some cases, the structural support member 20 may be surface-treated to contact only one of the inner bushing 18 or the outer sheath 24. As an example, the structural support member 20 may be selectively surface-treated on its inner radial surface but not on its outer radial surface, allowing the structural support member 20 to have increased adhesion to the inner bushing 18 or the support layer 22 between the inner bushing 18 and the structural support member 20. This increased adhesion can reduce movement of the structural support member 20 during positioning on the inner bushing 18. As another example, the structural support member 20 may be surface-treated on its outer radial surface but not on its inner radial surface, allowing the structural support member 20 to have increased adhesion to the outer sheath 24 or the support layer 22 between the outer sheath 24 and the structural support member 20. During the formation of the outer sheath 24, surface treatment can increase the surface area and / or reactivity of the surface of the structural support member 20, allowing the material of the outer sheath 24 to bond more firmly to the surface of the structural support member 20. In other cases, the structural support member 20 may be surface treated to contact both the inner bushing 18 and the outer sheath 24.

[0088] In some instances, surface treatments may be applied to, or present in varying amounts, on one or more specific portions of the structural support member 20 to increase adhesion between the structural support member 20 and the inner bushing 18 and / or the outer sheath 24. For example, these surface-treated portions may be certain portions of the structural support member 20 that may experience stresses more likely than other portions of the structural support member 20 that could cause separation from the inner bushing 18 and / or the outer sheath 24. For example, the surface of a first portion (such as a more distant portion) of the structural support member 20 may be surface-treated, while the surface of a second portion (such as a more proximal portion) of the structural support member 20 may not be surface-treated. Thus, the surface of the first portion of the structural support member 20 may have different surface properties than the surface of the second portion. For example, the surface of the first portion of the structural support member 20 may have a first surface roughness, and the surface of the second portion of the structural support member 20 may have a second surface roughness less than the first surface roughness. In some instances, the shear strength of the first portion is at least about 20% higher than the shear strength of the second portion.

[0089] In some instances, one or more portions of the structural support member 20 that may undergo relatively high deformation may be surface-treated. For example, a first portion of the structural support member 20 near the distal opening 13 may be adjacent to a more compressible, relatively low-indicative-stiffness section of the outer sheath 24. During the passage of the guide tube 10 through the vascular system, the first portion may experience relatively significant deformation, which could cause the outer sheath 24 to delaminate or detach from the structural support member 20.

[0090] In some instances, the surfaces of one or more portions of the structural support member 20 having a relatively high density (e.g., coil pitch or weft per inch) can be surface-treated. For example, a first portion of the structural support member 20 may have a relatively high coil pitch, and a second portion of the structural support member 20 may have a relatively low coil pitch. Due to the higher density, the coil-to-coil or braid-to-braid contact between the inner liner 18 and the outer sheath 24 may be lower in the first portion compared to the second portion of the structural support member 20. For example, during the formation of the outer sheath 24, the first portion of the structural support member 20 may have reduced flow of the outer sheath material between the structures of the structural support member 20 (e.g., adjacent turns of the coil). This is either directly (as in a three-layer conduit configuration) or through the support layer 22 (as in...). Figure 2 In the four-layer catheter configuration shown in the figure, this reduced flow of the outer sheath material compared to the second section may result in a reduced contact area between the inner liner 18 and the outer sheath 24 in the first section.

[0091] In some instances, the surfaces of one or more portions of the structural support member 20 having a relatively large diameter may be surface-treated. For example, a first portion of the structural support member 20 may have a relatively small diameter, and a second portion of the structural support member 20 may have a relatively large diameter. Due to the larger diameter in the second portion of the structural support member 20, the contact area between the coils or braids of the inner bushing 18 and the outer sheath 24 may be smaller in the second portion compared to the first portion of the structural support member 20.

[0092] exist Figure 2 In the examples shown, structural support member 20 is formed of wire shaped to define a coil, such as a circular (cross-section) wire. In other examples, member 20 may be formed at least partially of flat (cross-section) wire shaped to define a coil. A circular wire can define a coil member with a smaller surface area than a flat wire, such that for a given length of structural support member 20, the inner bushing 18 and / or the outer sheath 24 can have a higher contact area between the coils of structural support member 20. A flat wire can define a coil member with a larger surface area than a circular wire, such that for a given length of structural support member 20, structural support member 20 can have a higher contact area with the inner bushing 18 and / or the outer sheath 24.

[0093] The conductor forming member 20 can be a metallic conductor. In some instances, the conductor is formed of a shape memory material, such as a nickel-titanium alloy (NiTiNO). In other instances, the conductor is formed of stainless steel. In some cases, nickel-titanium alloys can be more resistant to compression than stainless steel, and therefore can be used to form the structural support member 20 of the conduit, which is more resistant to kinking and buckling compared to stainless steel. Additionally, as described in further detail below, shape memory materials can allow the structural support member 20 to be formed before it is positioned above the inner bushing 18. For example, the pitch and diameter of member 20 can be defined before member 20 is positioned above the inner bushing 18, which can provide certain advantages (discussed below). Conversely, when member 20 is formed of stainless steel, the pitch and diameter of member 20 can be defined such that member 20 is wound around the inner bushing 18.

[0094] In some instances, structural support member 20 comprises multiple longitudinally adjacent structures (e.g., connected to each other, adjacent to each other but not connected, or with gaps between them). In other instances, structural support member 20 is formed from a single conductor defining a coil member that varies the outer and inner diameters of structural support member 20, varies the outer diameter of the coil member, and varies the pitch along the length of member 20. The single conductor can be seamless (or jointless) because there are no joints (e.g., butt joints) between individual portions of the conductor that are joined together to define a longer conductor; instead, the conductor has a single-body construction. In some instances, the simultaneous variation of the pitch, as well as the inner and outer diameters, of structural support member 20 comprising a single seamless conductor can be achieved at least in part by forming the conductor with a shape memory material. Compared to instances where member 20 is formed from multiple conductors joined together, defining member 20 by a single seamless conductor can increase the structural integrity of conduit body 12. For example, joints between conductors can adversely affect the tensile strength or lateral flexibility of member 20, which can adversely affect the flexibility and maneuverability of conduit body 12.

[0095] In instances where structural support member 20 comprises a coil (e.g., a helical coil), the flexibility of structural support member 20 can be at least partially a function of the coil pitch. For a given conductor, a larger pitch results in a larger gap between adjacent turns of the conductor forming member 20 and a greater degree of flexibility. The pitch can be, for example, the width of a full turn of conductor measured along the longitudinal axis 16. In some instances, the pitch of structural support member 20 varies along the length of structural support member 20, such that stiffness (or flexibility) varies along the length. The pitch can vary continuously along the length of member 20 or can change gradually, for example, by comprising different segments, each segment having a corresponding pitch.

[0096] The flexibility of the outer sheath 24 can be at least in part a function of the composition, stiffness (e.g., indicated stiffness), and / or thickness of the outer sheath 24. For example, higher indicated stiffness may result in lower compressibility and lower flexibility. In order to configure the catheter body 12 to have a specific flexible profile (e.g., flexibility along the longitudinal axis 16), the outer sheath 24 may comprise a plurality of outer sheath segments having different properties and supported by variable density structural support members 20. Figure 3-4 Various catheters are shown, including variable density structural support members 20 that include one or more connections between sections for supporting the outer sheath 24.

[0097] Figure 3 It is an example conduit body containing a coiled structural support member 20 (e.g., Figure 2A conceptual cross-sectional view of a portion 30 of the catheter body 12), wherein the cross-section is through the center of the catheter body and along the longitudinal axis of the catheter body (e.g., Figure 1 The vertical axis 16) is truncated. Although in Figure 3 and 4 The description primarily refers to catheter body 12, but in other instances, portion 30 may be part of another catheter body.

[0098] exist Figure 3 In the example shown, portion 30 of the catheter body 12 includes an inner liner 18, an outer sheath 24, and a structural support member 20. The outer sheath 24 includes multiple outer sheath segments 34A and 34B (collectively referred to herein as “segment 34” or typically referred to individually as “segment 34”). Figure 3 In the example shown, only the first outer sheath segment 34A and the second outer sheath segment 34B are depicted; however, the catheter body 12 may include any number of outer sheath segments 34. Each segment 34 may be, for example, a sleeve (e.g., a tubular sleeve) configured to be positioned above the inner liner 18 and the structural support member 20, and, if present, the support layer 22, as will be described in the example. Figures 5A-5C Further details are provided below.

[0099] The segments 34 are positioned longitudinally adjacent to each other, for example, in an adjoining relationship, and in some instances, they may be mechanically joined together to define the outer sheath 24 using any suitable technique, such as by welding, adhesive, heating / reflow, or any combination thereof. Adjacent outer sheath segments 34 form a connection 32 between them; as... Figure 3 As shown, outer sheath segment 34A and outer sheath segment 34B form a connection 32. Segments 34 can each have any suitable length, which can be selected based on the desired flexible profile of the catheter body 12. In some examples, the proximal portion 17A, distal portion 17B, and intermediate portion 17C of the catheter body 12 ( Figure 1 The catheter may have its own corresponding outer sheath segment 34, each of which begins and ends at the proximal and distal ends of the corresponding catheter body portions 17A-17C. In other instances, one of the outer sheath segments 34 may extend at least above both the proximal portion 17A and the intermediate portion 17C and / or above both the intermediate portion 17C and the distal portion 17B.

[0100] The stiffness and / or rigidity (e.g., indicated rigidity) of the outer sheath 24 contributes to the flexibility and structural integrity of the catheter body 12. Therefore, the composition and properties (e.g., indicated rigidity and / or thickness) of each segment in the segment 34 can be selected to help provide the desired flexibility characteristics to the portion 30 of the catheter body 12.

[0101] In some instances, the composition of each segment in section 34 can be selected to provide the desired flexibility properties for the catheter body 12. For example, different materials can have different properties, such as indicative stiffness, compressibility, elasticity, etc. In some instances, at least two outer sheath sections 34 are formed of different materials (e.g., materials with different chemical compositions and / or different material properties). Example materials used for sections 34 include, but are not limited to, polymers such as polyether block amides (e.g., PEBAX®, commercially available from Arkema Group of Colombes, France), aliphatic polyamides (e.g., Grilamid®, commercially available from EMS-Chemie of Sumter, South Carolina), another thermoplastic elastomer or other thermoplastic materials, or combinations thereof. In one instance, the closer section (e.g., section 34A) is formed of aliphatic polyamide, and the more distant section (e.g., section 34B) is formed of polyether block amide. The composition of polyether block amides can be modified to obtain segments 34 with different measured hardness.

[0102] In some instances, the indicated stiffness of each segment of section 34 can be selected to help provide the desired flexibility properties to the catheter body 12. For example, at least two outer sheath segments 34 may have different indicated stiffnesses. In some instances, the indicated stiffness of section 34 may be between about 30A and 100A or between 25D and about 90D. However, in other instances, one or more segments of section 34 may have other stiffness values. The stiffness of section 34 can be selected to achieve more or less flexibility, torsion, and maneuverability in all or part of the catheter body 12.

[0103] In some instances, such as the example portion of the catheter body 12, where the flexibility of the catheter body 12 increases from the proximal end 12A to the distal end 12B, the apparent stiffness of two adjacent outer sheath segments 34 may decrease in the direction from the proximal end to the distal end of the outer sheath 24. For example, the apparent stiffness of the first outer sheath segment 34A may be greater than the apparent stiffness of the second outer sheath segment 34B. Thus, the catheter body 12 can be more flexible for guiding the guide tube 10 through the patient's vascular system.

[0104] In some instances, such as the example portion of catheter body 12, where the flexibility of catheter body 12 decreases along any portion of catheter body 12 from proximal end 12A to distal end 12B, the indicated stiffness of two adjacent outer sheath sections 34 can increase in the direction from the proximal end to the distal end of the outer sheath 24. For example, the indicated stiffness of the first outer sheath section 34A can be less than the indicated stiffness of the second outer sheath section 34B. Although in some cases it may be desirable to provide catheter body 12 with a relatively flexible distal portion, as described above, increasing the indicated stiffness of the distal section of outer sheath 24 relative to the more proximal section directly adjacent to the distal section can provide certain advantages. For example, increasing the indicated stiffness of the distal section can configure the distal opening 13 of catheter body 12 at the distal opening 13 of catheter body 12 ( Figure 1 When engaged with the guidewire, it resists geometric deformation, which can help support the guide tube body 12 as it passes through the vascular system. The distal section of the outer sheath 24, exhibiting increased stiffness, can be a relatively small length of the catheter body 12 and therefore can be used without affecting the overall flexibility of the catheter body 12.

[0105] In some instances, the structural support member 20 comprises one or more segments, which contain different properties related to the flexibility of the conduit body 12, such as the structural density and diameter of the structural support member 20. Figure 3 In one example, the structural support member 20 includes a first section 36A, a second section 36B distal to the first section 36A, and a third section 36C distal to the second section 36B (collectively referred to as “section 36” and usually referred to individually as “section 36”).

[0106] In some instances, the structural support member 20 includes one or more relatively high-density segments 36 interspersed with relatively low-density segments 36. Due to discontinuities between adjacent outer sheath segments 34 and / or the different properties of said adjacent outer sheath segments, the connection 32 between adjacent outer sheath segments 34 may be a relatively weak location where the catheter body 12 is more likely to buckle, kink, or collapse. As mentioned above, the density of the structural support member 20 can be inversely proportional to the compressibility of the structural support member 20, such that the relatively high-density segments of the structural support member 20 can be less flexible and / or more compressible than the relatively low-density segments of the structural support member 20. In some instances, to reinforce the connection 32, the structural support member 20 has a higher variable density near the connection 32. For example, in Figure 3In the example, the first segment 36A of the structural support member 20 has a first density, the second segment 36B of the structural support member 20 has a second density, and the third segment 36C of the structural support member 20 has a third density, wherein the second density of the second segment 36B is higher than the first density of the first segment 36A and the third density of the third segment 36C, respectively.

[0107] In some instances, structural support member 20 comprises coils comprising different segments with different corresponding pitches. An increase in the density of structural support member 20 may correspond to a decrease in the pitch of structural support member 20 (e.g., the spacing between coils or braids). Figure 3 As shown, the pitch of the structural support member 20 decreases in the distal direction from the first segment 36A to the second segment 36B, and increases in the distal direction from the second segment 36B to the third segment 36C. In one example, the pitch of the higher-density segment of the structural support member 20 (such as the second segment 36B) may be greater than about 25% and less than about 75% of the pitch of the adjacent lower-density portion 36 of the structural support member 20 (such as the first segment 36A or the third segment 36C). Although the segments 36 are shown to have a gradual density transition, in some examples, the density transition of the structural support member 20 may be gradual. In some examples, the pitch of the structural support member may be between about 0.00225 inches (about 0.057 mm) and about 0.0070 inches (about 0.018 mm).

[0108] The second segment 36B is longitudinally aligned with the connection 32 between the first outer sheath segment 34A and the second outer sheath segment 34B. For example, the second segment 36B may longitudinally overlap with a portion of the first outer sheath segment 34A and the second outer sheath segment 34B, such as by more than about 5 mm (measured along the longitudinal axis 16). The relatively high density of the second segment 36B allows a portion 30 of the catheter body 12 to resist compression and thus buckle at the connection 32, making the structural support member 20 less likely to collapse at the connection 32 in response to compressive or bending forces experienced as the guiding catheter 10 passes through the patient's vascular system, compared to a catheter with a relatively high-density segment that does not contain a structural support member at the connection between two adjacent outer sheath segments.

[0109] In some instances, the surfaces of one or more sections of the structural support member 20 may be surface-treated to increase adhesion of the surface to at least one of the inner bushing 18 and / or the outer sheath 24. For example, as described above regarding Figure 2The explained structural support member 20, with its relatively high density, can exhibit reduced flow of the outer sheath material between the structures of the structural support member 20 and / or reduced contact area with the inner liner 18 and / or support layer 22. Surface treatment can help compensate for any adverse effects on the kinking, compression, or buckling resistance of the conduit body 12 attributable to this reduced contact area. Figure 3 In one example, the second segment 36B contains a higher density, allowing at least the second segment 36B of the structural support member 20 to be surface treated to increase the adhesion of the surface of the second segment 36B to at least one of the inner liner 18 and / or the first outer sheath segment 34A and / or the second outer sheath segment 34B.

[0110] During the passage of the guiding catheter 10 through the patient's vascular system, the bending of the catheter body 12 can exert compressive forces on the inner radius of the catheter body 12 (e.g., at portion 30). Without the variable-density structural support member 20, these compressive forces could cause portion 30 to twist or buckle near the connection 32. However, the higher density of the second segment 36B of the structural support member 20 can reinforce the connection 32 to distribute forces more evenly, such as to the portion of the catheter body 12 adjacent to the connection 32.

[0111] In some cases, the combination of variable density structural support members with an outer sheath 24 of variable composition, indicated stiffness and / or thickness can further configure the flexibility of the catheter body. Figure 4 It is a conduit body containing a braided structure support member 21 (e.g., Figure 2 A conceptual cross-sectional view of a portion 40 of the catheter body 12, wherein the cross-section is taken through the center of the catheter body 12 and along the longitudinal axis of the catheter body 12. The braided structure support member 21 may be... Figure 2 An example of structural support member 20, which allows the features of woven structural support member 21 to be applied. Figure 2 The structural support component 20, and vice versa.

[0112] The catheter body 12, portion 40, includes an inner liner 18, an outer sheath 24, and a structural support member 21. The outer sheath 24 includes multiple outer sheath segments 44A, 44B, and 44C (collectively referred to herein as “segment 44” or typically individually as “segment 44”). Figure 4 In this example, only the first outer sheath segment 44A, the second outer sheath segment 44B, and the third outer sheath segment 44C are shown; however, in other examples, portion 40 and the catheter body 12 may include any suitable number of outer sheath segments 44. Adjacent outer sheath segments 44 form a connecting portion 42 between adjacent outer sheath segments 44; as... Figure 4As shown, outer sheath segment 44A and outer sheath segment 44B form a connecting portion 42A, and outer sheath segment 44B and outer sheath segment 44C form a connecting portion 42B. Segment 44 can be similar to the above. Figure 3 Section 34.

[0113] In some instances, the structural support member 21 comprises one or more segments, which contain different properties related to the flexibility of the conduit body 12, such as the structural density and diameter of the structural support member 21. Figure 4 In one example, structural support member 21 includes a first segment 46A, a second segment 46B distal to the first segment 46A, and a third segment 46C distal to the second segment 46B (collectively referred to as “segment 46” and usually referred to individually as “segment 46”). Segment 46 may be similar to the one described above. Figure 3 Section 36.

[0114] In some instances, the structural support member 21 may be configured to reinforce one or more connection portions 42 and one or more outer sheath segments 44. For example, the flexibility of the catheter body 12 may be at least in part a function of the flexibility of the structural support member 21 and the outer sheath 24. Thus, various flexibility properties of different structural support member segments 46 and outer sheath segments 44 may be configured to combine to produce a desired flexible profile of portions 40 of the catheter body 12.

[0115] As an example, in Figure 4In this example, the first segment 46A of the structural support member 21 is adjacent to the first outer sheath segment 44A (e.g., in the radial direction), the second segment 46B of the structural support member 21 is adjacent to the second outer sheath segment 44B, and the third segment 46C of the structural support member 21 is adjacent to the third outer sheath segment 44C. The outer sheath 24 may exhibit a gradually decreasing indicated hardness, such that the first outer sheath segment 44A has a first indicated hardness, the second outer sheath segment 44B has a second indicated hardness lower than the first indicated hardness of the first outer sheath segment 44A, and the third outer sheath segment 44C has a third indicated hardness lower than the first indicated hardness of the first outer sheath segment 44A and the second indicated hardness of the second outer sheath segment 44B, respectively. The first segment 46A of the structural support member 21 has a first density, the second segment 46B of the structural support member 21 has a second density, and the third segment 46C of the structural support member 21 has a third density, such that the second density of the second segment 46B is higher than the first density of the first segment 46A and the third density of the third segment 46C, respectively. Therefore, portion 40 forms a generally three-part conduit body 12, comprising a proximal portion with relatively low density and relatively high indicated stiffness for relatively low net flexibility; an intermediate portion with relatively high density and relatively medium indicated stiffness for relatively medium net flexibility; and a distal portion with relatively low density and relatively low indicated stiffness for relatively high net flexibility. Figure 4 As shown, the second segment 46B overlaps with a portion of each of the first outer sheath segment 44A and the third outer sheath segment 44C to reinforce the connections 42A and 42B. In this way, the catheter body, which incorporates variable flexibility features in the structural support member 21 and the outer sheath 24, can be configured with a more specific flexible profile that provides increased structural integrity.

[0116] In some instances, the conduit described herein may include structural support members whose diameter may vary along the length of the structural support members. Figure 5A This is a conceptual cross-sectional view of a portion of the catheter body including a tapered structural support member, wherein the cross-section is taken through the center of the catheter body and along the longitudinal axis of the catheter body. Portion 50 of the catheter body 12 includes an inner liner 18, an outer sheath 24, a structural support member 20, and a support layer 22. However, in other instances, such as the catheter body or portions of a catheter body comprising a three-layer configuration, the support layer 22 may be omitted. Portion 50 includes a proximal portion 52A and a distal portion 52B.

[0117] Figure 5B yes Figure 5A The proximal portion 52A of the catheter body 12 is along the... Figure 5A The conceptual cross-sectional view intercepted by line AA in the middle, and Figure 5C yes Figure 5AThe distal portion 52B of the catheter body 12 is along the... Figure 5A A conceptual cross-sectional view taken from line BB in the diagram. Figures 5A-5C In this example, the outer sheath 24 includes a proximal outer sheath segment 60A and a distal outer sheath segment 60B (collectively referred to as “segment 60” and individually referred to as “segment 60”); the support layer 22 includes a proximal segment 58A and a distal segment 58B (collectively referred to as “segment 58” and individually referred to as “segment 58”); and the structural support member 20 includes a proximal segment 56A and a distal segment 56B (collectively referred to as “segment 56” and individually referred to as “segment 56”).

[0118] In some instances, the structural support member 20 may taper and / or extend at various portions (such as portion 50) of the conduit body 12. Figures 5A-5C As shown in Example 50, the structural support member 20 tapers from a first diameter at the proximal portion 52A to a second diameter at the distal portion 52B. For example, the structural support member 20 may taper from a first larger coil diameter to a second smaller coil diameter. Diameters, such as the inner diameter and / or outer diameter of the structural support member 20, can be measured. Figures 5A-5C In the example shown, the proximal section 56A of the structural support member 20 has a first coil outer diameter, and the distal section 56B of the structural support member 20 has a second coil outer diameter smaller than the first coil outer diameter, such that the structural support member 20 gradually shrinks from the first coil outer diameter to the second coil outer diameter.

[0119] In other instances where the inner liner 18 also tapers from a first outer (and / or inner) diameter to a second outer (and / or inner) diameter (smaller than the first outer (and / or inner) diameter), and in instances where the catheter body 12 tapers from a first outer diameter to a second outer diameter or both, the structural support member 20 may taper with the change in the outer diameter of the inner liner 18, the catheter body 12, or both the inner liner 18 and the catheter body 12.

[0120] In some instances, at least two outer sheath sections 60 have different thicknesses or diameters. For example, the smaller diameter portion of the structural support member 20 (such as the smaller diameter distal section) can have increased flexibility and allow the thicker outer sheath to have lower nominal stiffness and thus a more flexible material, while also allowing the conduit to maintain a relatively constant inner diameter of the inner liner 18 and outer diameter of the outer sheath 24.

[0121] In some instances, such as... Figure 1The illustrated example shows a structural support member 20 whose outer diameter decreases (e.g., tapers) from proximal end 12A to distal end 12B. The thickness of each outer sheath segment 60 can increase in the direction from proximal end to distal end of the outer sheath 24. For example, the outer sheath 24 can extend from a first inner diameter to a second, larger inner diameter. Figure 5B and 5C In the example shown, the proximal outer sheath segment 60A has a first sheath inner diameter, and the distal outer sheath segment 60B has a second sheath inner diameter, such that the outer sheath 24 extends from the first sheath inner diameter to the second sheath inner diameter. Therefore, the thickness of the proximal outer sheath segment 60A can be less than the thickness of the distal outer sheath segment 60B, and the thickness of the proximal segment 58A of the support layer 22 can be greater than the thickness of the distal segment 58B of the support layer 22.

[0122] In some instances, such as... Figure 1 In the example shown, the outer diameter of the catheter body 12 tapers near the distal end 12B, and the thickness of adjacent outer sheath segments 60 may decrease in the direction from the proximal end to the distal end of the outer sheath 24. For example, the thickness of the first outer sheath segment 60A may be greater than the thickness of the second outer sheath segment 60B. In some instances, at least two segments 60 may also define different inner diameters from each other, wherein the inner diameter of a particular segment 60 may be selected to accommodate the portion of the catheter body 12 in which the sleeve corresponding to the segment 60 is positioned. In some instances, each segment 60 has the same wall thickness (in the direction orthogonal to the longitudinal axis 16 ( Figure 1 (Measured in the direction of ). In other instances, the wall thickness of section 60 may vary.

[0123] The catheters described herein can be formed using any suitable technique. Figure 6 and 7 It is formed Figure 1 and 2 Catheter 10 Figure 3 Part 30 Figure 4 Part 40 and / or Figures 5A-5C The flowchart of any of the example methods in section 50. Figure 6 It is to form structural support components with surface treatment. Figure 1-5C A flowchart of an example method for constructing a catheter, and references will be provided. Figure 1 The catheter 10 is described.

[0124] according to Figure 6The technique illustrated involves surface-treating the structural support member 20 by applying a surface treatment to at least a portion of its surface to increase adhesion between the structural support member 20 and the inner bushing 18 and / or the outer sheath 24. In some instances, the surface treatment is applied to the entire structural support member 20. In other instances, the surface treatment is applied only to a portion, leaving the other portions of the structural support member 20 untreated in the same manner. As an example, in some cases, the structural support member 20 may be surface-treated to contact only one of the inner bushing 18 or the outer sheath 24. In some instances, applying the surface treatment involves applying it to the inner radial surfaces of the structural support member 20, while substantially not applying it to the outer radial surfaces, such that the structural support member 20 can have increased adhesion to the inner bushing 18 or the support layer 22 between the inner bushing 18 and the structural support member 20. For example, surface treatment may involve the inner radial surfaces of the structural support member 20; although some surfaces of the outer radial surfaces of the structural support member 20 may be unintentionally treated during this process, most of the outer radial surfaces may remain untreated.

[0125] In some instances, the application of surface treatment involves applying the surface treatment to the outer radial surface of the structural support member 20 while substantially not applying the surface treatment to the inner radial surface of the structural support member 20, such that the structural support member 20 may have increased adhesion to the outer sheath 24 or the support layer 22 between the outer sheath 24 and the structural support member 20.

[0126] In some instances, surface treatments include physical treatments, either alone or in combination with other surface treatments described herein. Physical treatments include any treatment that may result in an increase in the contact area of ​​the surfaces of the structural support member 20 used for bonding with the inner layer 18, the outer sheath 24, and / or the support layer 22, or an increase in the mechanical interlocking between the surface of the structural support member 20 and the inner sheath 18, the outer sheath 24, and / or the support layer 22. For example, physical treatments may increase the surface area or surface deviation (e.g., tilt angle) of the surface of the structural support member 20. Various physical treatments may be used, including, but not limited to, mechanical roughening, laser roughening, abrasion, etc.

[0127] In some instances, the surface treatment involves roughening the surface of at least a portion of the structural support member to increase its surface roughness. The increased surface roughness can be, for example, an increased contact area, contact slope, and / or fractal nature between the surface of the structural support member 20 and the inner bushing 18, outer sheath 24, and / or support layer 22, thereby increasing the adhesion between the structural support member 20 and the inner bushing 18, outer sheath 24, and / or support layer 22. In some instances, the surface roughness of at least a portion of the surface of the structural support member is greater than approximately [minimum surface roughness measurement].

[0128] In some instances, the surface treatment includes chemical treatments, either alone or in combination with other surface treatments described herein. Chemical treatments include any treatment that may result in increased chemical bonding between the structural support member 20 and the inner liner 18, outer sheath 24, and / or support layer 22. For example, a chemical treatment may increase the charge or reactivity of the surface of the structural support member 20 to increase the intermolecular forces between the structural support member 20 and the inner liner 18, outer sheath 24, and / or support layer 22. Various chemical treatments may be used, including but not limited to alkali treatments, acid treatments, ionization, protonation, deprotonation, electric field charges, etc.

[0129] In some instances, the surface treatment involves chemically treating at least a portion of the surface of the structural support member 20 to increase the surface charge. The increased surface charge may be opposite to the charge of the inner liner, outer coating, and / or support layer, thereby increasing the electrostatic attraction between the structural support member and the inner liner, outer sheath, and / or support layer. For example, the structural support member 20 may contain a positive charge, while the outer sheath 24 may contain a negative charge, such that the structural support member 20 and the outer sheath 24 can electrostatically attract each other.

[0130] In some instances, the surface treatment involves chemically treating at least a portion of the surface of the structural support member 20 to functionalize the surface with reactive portions. For example, the surface of the structural support member 20 may react with an acid or base to generate reactive portions, such as amines, carboxylic acids, or other reactive groups configured to react with a polymer. The inner liner 18, the outer sheath 24, and / or the support layer 22 may comprise a polymer containing various functional groups capable of reacting with the reactive portions on the structural support member 20. The reactive portions on the structural support layer may be bonded (e.g., covalently) to the functional groups of the inner liner 18, the outer sheath 24, and / or the support layer 22. Thus, at least a portion of the surface of the structural support member 20 may be covalently bonded to at least one of the inner liner 18 or the outer sheath 24.

[0131] In some instances, surface treatment may comprise a coating treatment, either alone or in combination with other surface treatments described herein. The coating treatment may comprise, for example, coating a portion of the surface of a structural support member with a functional layer, such as a reactive layer having reactive portions. The functional layer may provide the roughness, charge, and / or reactive properties described above with respect to physical or chemical treatments, rather than providing surface properties through direct surface treatment of the structural support member. In some instances, applying a surface treatment comprises coating at least a portion of the surface of the structural support member 20 with a reactive layer having reactive portions. For example, the surface of the structural support member 20 may comprise a polymer coating containing reactive portions configured to react with functional groups of the inner liner 18, the outer sheath 24, and / or the support layer 22, such that the coating can be covalently bonded to at least one of the inner liner 18 or the outer sheath 24.

[0132] In some instances, applying surface treatment involves applying the treatment to specific portions of the structural support member 20, or in varying amounts, to increase adhesion between the structural support member 20 and the inner bushing 18 and / or the outer sheath 24. For example, the surface of a first portion (e.g., a more distant portion) of the structural support member 20 may be surface-treated, while the surface of a second portion (e.g., a more proximal portion) of the structural support member 20 may not be surface-treated or may be treated differently. Therefore, the surface of the first portion of the structural support member 20 may have different surface properties than the surface of the second portion. In some instances, the surface of the first portion of the structural support member 20 may have a first surface roughness, and the surface of the second portion of the structural support member 20 may have a second surface roughness less than the first surface roughness. In some instances, the shear strength of the first portion is at least 20% higher than the shear strength of the second portion.

[0133] In some instances, surface treatments may be applied to one or more portions of the structural support member 20 that may undergo relatively high deformation. For example, a first portion of the structural support member 20 near the distal opening 13 may be adjacent to a more compressible, relatively low-indicative-stiffness section of the outer sheath 24. During the passage of the guide tube 10 through the vascular system, the first portion may experience relatively significant deformation, which could cause the outer sheath 24 to delaminate or detach from the structural support member 20. Therefore, the first portion may include a surface treatment to help compensate for the stresses that could cause the outer sheath 24 to delaminate or detach from the structural support member 20.

[0134] In some instances, surface treatments may be applied to one or more portions of the structural support member 20 that have a relatively high density. For example, a first portion of the structural support member 20 may have a relatively high coil pitch or weft per inch, and a second portion of the structural support member 20 may have a relatively low coil pitch or weft per inch. Due to the higher coil pitch, the coil-to-coil or braid-to-braid contact between the inner liner 18 and the outer sheath 24 may be lower in the first portion compared to the second portion of the structural support member 20. For example, during the positioning of the outer sheath 24 as described below, the first portion of the structural support member 20 may have reduced flow or backflow of the outer sheath material between the structures (e.g., coils) of the structural support member 20. This may occur either directly (as in a three-layer conduit configuration) or through the support layer 22 (as in...). Figure 2 In the four-layer catheter configuration shown in the figure, this reduced flow of the outer sheath material compared to the second section may result in a reduced contact area between the inner liner 18 and the outer sheath 24 in the first section.

[0135] For example, in Figure 2 In some examples, the structural support member 20 is a coiled structural support member and may include a first portion having a first coil pitch and a second portion having a second coil pitch smaller than the first coil pitch. In some examples, applying a surface treatment includes applying the surface treatment to the surface of the first portion of the structural support member 20 and avoiding applying the surface treatment to the surface of the second portion of the structural support member 20. For example, applying a surface treatment may include roughening the surface of the first portion of the structural support member 20 without roughening the surface of the second portion of the structural support member 20. In some examples, applying a surface treatment includes applying the surface treatment to the surface of the first portion of the structural support member 20 and applying the surface treatment to the surface of the second portion of the structural support member 20 to a lesser extent than applying the surface treatment to the first portion of the structural support member 20. For example, applying a surface treatment may include roughening the surface of the first portion of the structural support member 20 to a first surface roughness and roughening the surface of the second portion of the structural support member 20 to a second surface roughness smaller than the first surface roughness. As another example, the surface treatment may include chemically treating the surface of a first portion of the coiled structural support member to a first charge and chemically treating the surface of a second portion of the coiled structural support member to a second charge less than the first charge.

[0136] In some instances, surface treatments may be applied to one or more portions of the structural support member 20 that have a relatively large inner or outer diameter. For example, a first portion of the structural support member 20 may have a relatively small diameter, and a second portion of the structural support member 20 may have a relatively large diameter. Due to the larger diameter in the second portion of the structural support member 20, the contact area between the coils or braids of the inner bushing 18 and the outer sheath 24 may be smaller in the second portion compared to the first portion of the structural support member 20.

[0137] At any time before (102) the structural support member 20 is positioned above the inner bushing 18, the inner bushing 18 may be positioned above a mandrel (not shown). In some instances, the inner bushing 18 may be positioned above a mandrel by inserting at least the mandrel through the end of the inner bushing 18. After the inner bushing 18 is positioned above the mandrel, the surface-treated structural support member 20 may be positioned above the inner bushing 18 (102). In instances where the structural support member 20 includes a coil member, the wire defining the coil member may be wound above or pushed above the outer surface of the inner bushing 18. The coil member may be, for example, a single coil member without any joints. In some instances, the structural configuration of the structural support member 20 may be at least partially defined as being wound above the inner bushing 18. For example, shape memory wire or stainless steel wire may be wound above the inner bushing 18 to define a desired coil pitch, one or more desired diameters, a desired taper, a desired length, or any combination thereof for the member 20. The shape memory wire can then be thermally molded into a defined structural support member 20.

[0138] Any suitable technique can be used to secure the structural support member 20 in place relative to the inner liner 18. In some instances, the outer sheath 24 may at least partially secure the structural support member 20 to the inner liner 18. After the structural support member 20 is positioned above the inner liner 18 (102), the outer sheath 24 is positioned above the outer surface of the structural support member (104). During and / or after positioning the outer sheath 24, material of the outer sheath 24 may flow and / or recirculate between the structures of the structural support member 20 (e.g., coils or braids) such that at least a portion of the volume between the structures of the structural support member 20 may be filled with material of the outer sheath 24. In some cases, the material of the outer sheath 24 may contact the inner liner 18 to form an interface between the inner liner 18 and the outer sheath 24. This interface may provide adhesion between the inner liner 18 and the outer sheath 24, in addition to adhesion between the structural support member 20 and the inner liner 18 or the outer sheath 24. Regardless of whether the inner liner 18 and the outer sheath 24 form an interface, the outer sheath 24 can provide longitudinal support for the structural support member 20, thereby at least partially restricting the movement of the structural support member 20 between the inner liner 18 and the outer sheath 24. In this way, the outer sheath 24 can facilitate the integration of the structural support member 20 into the conduit body 12.

[0139] In some instances, adhesives and / or polymers, such as support layer 22, may be used to secure structural support member 20 to inner liner 18. As described above, in some instances, conduit body 12 includes support layer 22. To form support layer 22, a layer of thermoplastic or thermosetting polymer may be applied over structural support member 20 after it has been positioned over inner liner 18 (102), while in other instances, a layer of thermoplastic or thermosetting polymer may be applied over inner liner 18 before structural support member 20 has been positioned over inner liner 18. Thermosetting polymer may be, for example, a viscoelastic thermosetting polyurethane (e.g., Flexobond 430). At least some of the polymers may be positioned between turns of the wires defining member 20.

[0140] Positioning the thermosetting polymer over the inner liner 18 and structural support member 20 in this manner facilitates bonding the inner liner 18 and structural support member 20 to the outer sheath 24 via the support layer 22. For example, the polymer can contact the surfaces of the structural support member 20, including surfaces with surface treatments, and provide surfaces for bonding with the outer sheath 24. Conversely, depositing the polymer over the inner liner 18 prior to positioning the structural support member 20 may result in surfaces of the structural support member 20 without polymer, where these surfaces may not bond to the outer sheath 24 as easily or firmly as the surfaces of the support layer 22. After the polymer is positioned over the inner liner 18 and structural support member 20 (not shown), the polymer is cured (not shown), for example by heat and / or time curing. In other instances, the polymer may be cured after the outer sheath 24 is positioned over the inner liner 18, structural support member 20, and polymer.

[0141] The outer sheath 24 can then be positioned over the inner liner 18, structural support member 20, and support layer 22 (104). In some instances, the outer sheath 24 is adhered to the outer surface of the structural support member 20, for example, by applying an adhesive and / or polymer to the outer surface of the member 20 before positioning the outer sheath 24 over the member 20 and then curing it after the outer sheath 24 is positioned over the member 20. In addition to or instead of an adhesive, the outer sheath 24 can be heat-shrink over the member 20 and the inner liner 18. In some instances, the heat shrinkage of the outer sheath 24 helps to hold the member 20 in place relative to the inner liner 18.

[0142] In some instances, the inner bushing 18, outer sheath 24, and / or support layer 22 can physically interact directly with the surface-treated structural support member 20. As an example, the structural support member 20 can have increased friction and / or bonding surfaces with the inner bushing 18, outer sheath 24, and / or support layer 22. Increased surface roughness can increase the contact area, contact slope, and / or fractal nature of the surface of the structural support member 20 with the inner bushing 18, outer sheath 24, and / or support layer 22, thereby increasing adhesion between the structural support member 20 and the inner bushing 18, outer sheath 24, and / or support layer 22. As another example, the structural support member 20 can have increased mechanical interlocking with the outer sheath 24 and / or support layer 22. For example, the material of the outer sheath 24 and / or support layer 22 can flow or permeate into localized deviations on the surface of the structural support member 20 caused by the increased roughness.

[0143] In some instances, the inner liner 18, outer sheath 24, and / or support layer 22 may chemically interact with the surface-treated structural support member 20. As an example, the increased charge on the surface of the structural support member 20 may be opposite to the charge of the inner liner 18, outer sheath 24, and / or support layer 22, thereby increasing the electrostatic attraction between the structural support member 20 and the inner liner 18, outer sheath 24, and / or support layer 22. As another example, the inner liner 18, outer sheath 24, and / or support layer 22 may comprise a polymer containing various functional groups capable of reacting with reactive portions on the structural support member 20. The reactive portions on the structural support member 20 may be bonded (e.g., covalently) to the functional groups of the inner liner 18, outer sheath 24, and / or support layer 22, such that at least a portion of the surface of the structural support member 20 may be covalently bonded to at least one of the inner liner 18 or outer sheath 24.

[0144] Figure 7 It forms an outer sheath comprising multiple outer sheath segments. Figure 1-5C A flowchart of an example method for constructing a catheter, and references will be provided. Figure 3 The portion 30 of the catheter body 12 is described below. Figure 7 The technology shown allows the structural support member 20 to be positioned above the inner bushing 18 (102), as described above regarding... Figure 6 As described.

[0145] Structural support member 20 includes one or more relatively high-density sections interspersed with relatively low-density sections. Figure 3 In the example, the first segment 36A of the structural support member 20 has a first density, the second segment 36B of the structural support member 20 has a second density, and the third segment 36C of the structural support member 20 has a third density, such that the second density of the second segment 36B is higher than the first density of the first segment 36A and the third density of the third segment 36C, respectively.

[0146] In some instances, the structural configuration of the structural support member 20 may be at least partially defined before it is positioned over the inner bushing 18. For example, shape memory wire (e.g., nickel-titanium wire) or wire of a metal or alloy that is otherwise heat-stable may be wound over or over a different mandrel (e.g., a “coil mandrel”) on which the inner bushing 18 is not located (e.g., before the inner bushing 18 is positioned on the mandrel) to define at least one of the following: desired coil pitch, desired coil diameter, desired tapered profile (e.g., continuous tapered or progressive tapered), or desired length of the structural support member 20, and then heat-set to substantially maintain its shape. The wire may then be unwound from the mandrel onto a spool or bobbin and then positioned over the inner bushing 18. The structural support member 20 can be positioned above the inner liner 18, for example, by wrapping the member 20 over the inner liner 18 (e.g., by wrapping the member 20 from a spool or reel onto the inner liner 18) or by pushing the inner member 20 over the end of the inner liner 18.

[0147] In some instances, wires formed from shape memory metals / alloys or other heat-stable metals / alloys can be pre-formed into helical coils with a constant pitch and a desired diameter (including a desired taper), and then, once positioned above the bushing 18, the arrangement of the coiled wires can be adjusted to achieve a desired pitch profile (e.g., pitch variation over length) for the structural support member 20. For example, the pitch of the wires can be adjusted above the bushing 18 to achieve the desired pitch profile. These adjustments can be made manually, by hand, or by a computer-controlled device. However, in other instances, the wires can be pre-formed into helical coils with a desired pitch profile and diameter for the structural support member 20 before being positioned above the bushing 18.

[0148] Defining some or all of the structural characteristics of the structural support member 20 before positioning the member 20 above the inner liner 18 can help control the structural characteristics of the structural support member 20, as well as the uniformity of the structural support members 20 across multiple catheter bodies. Pre-forming and shaping the member 20 into a coil (as opposed to a conventional wire) ensures that the member 20 fits snugly against the liner 18 when it is wound around the inner liner 18. This snug fit, in itself, combined with the resulting reduction in the need for adhesives or other measures to hold the wound member in proper position on the liner 18, helps reduce the wall thickness T in the catheter body 12. Furthermore, shaping the structural support member 20 on a separate heat-resistant mandrel allows the catheter body 12 to be constructed using the member 20 on a mandrel made of PTFE or other lubricated, non-heat-resistant materials.

[0149] After the structural support member 20 is positioned above the inner liner 18 (102), the outer sheath 24 is positioned above the structural support member 20 and the inner liner 18 to form the conduit body 12. The outer sheath 24 includes a plurality of outer sheath segments 34, such that positioning the outer sheath 24 above the structural support member 20 and the inner liner 18 may include positioning a plurality of sleeves around the structural support member 20 and the inner liner 18. For example, each sleeve may slide above the outer surface of the member 20 and be positioned longitudinally adjacent to at least one other sleeve. Each of the plurality of sleeves may correspond to one or more outer sheath segments 34.

[0150] The sleeves can have different compositions and / or properties. For example, at least two sleeves can have different materials, different indicated hardness, and / or different thicknesses. In some instances, the order in which the sleeves are positioned can define an increase or decrease in the flexibility of the catheter body 12. As an example, to increase the flexibility from the proximal to the distal end of portion 30, the indicated hardness of the first sleeve is greater than that of the second sleeve, such that the indicated hardness of the first outer sheath segment 34A is greater than that of the second outer sheath segment 34B. As another example, to decrease the flexibility from the proximal to the distal end of portion 30, the indicated hardness of the first sleeve is less than that of the second sleeve, such that the indicated hardness of the first outer sheath segment 34A is less than that of the second outer sheath segment 34B.

[0151] exist Figure 7 In one example, forming the outer sheath 24 includes positioning a first sleeve corresponding to the first outer sheath segment 34A above the structural support member 20 (110) and positioning a second sleeve corresponding to the second outer sheath segment 34B above the structural support member 20, distal to the first sleeve (112). The first and second sleeves can be positioned such that the second segment 36B of the structural support member 20 is longitudinally aligned with the connection 32 between the first and second outer sheath segments 34A and 34B. After the catheter body 12 is constructed, the structural support member 20 will have a higher variable density near the connection 32, thereby compelling the connection 32.

[0152] After positioning the outer sheath section 34, the outer sheath section 34 can be mechanically joined together at the connection 32 and configured to substantially adhere to the outer surfaces of the structural support member 20, the inner bushing 18, and / or the support layer (not shown) using any suitable technique. In some instances, the section 34 is formed of a flowable / reflowable material. Heat can be applied to the section 34 to melt at least a portion of the section 34 and flow into the space between the structures of the structural support member 20. The heat can cause the section 34 to at least partially fuse together to define a substantially continuous outer sheath 24. Applying heat to the subassembly comprising the inner bushing 18 and the structural support member 20 can help eliminate the need for adhesives and / or support layers between the structural support member 20 and the outer sheath 24.

[0153] In some instances, segment 34 is formed of a heat-shrinkable material. A heat-shrinkable tube can be positioned above segment 34, and heat can be applied to tightly wrap the heat-shrinkable tube around segment 34. The heat and wrapping force can fuse segment 34 together to define a substantially continuous outer sheath 24. The heat-shrinkable tube can then be removed from the assembly, for example, by scraping or any suitable technique. Applying the outer sheath 24 to the subassembly comprising an inner liner 18, a support layer (optional and not shown), and a structural support member 20 using heat shrink can help eliminate the need for an adhesive between the structural support member 20 and the outer sheath 24. This can help minimize the wall thickness of the conduit body 12 and thus increase the inner diameter of the conduit body 12 for a given outer diameter. Additionally, the absence of an adhesive layer to adhere the structural support member 20 to the outer sheath 24 can help increase the flexibility of the conduit body 12.

[0154] In some instances, unless otherwise specified, see references. Figure 1 The method of using catheter 10, as described herein, includes introducing catheter 10 into the patient's vascular system (e.g., intracranial vessels) through an entry point (e.g., the femoral or radial artery) and guiding catheter body 12 through the vascular system. In some cases, catheter body 12 may encounter a tortuous vascular system that exerts bending or compressive forces on catheter body 12 in response to thrust or rotational forces at the proximal end of catheter 10. As catheter body 12 advances through a tortuous vascular system, catheter body 12 can resist kinking or flexion. As an example, such as Figure 2 As shown, the structural support member 20 can remain adhered to the outer sheath 24 and / or the inner liner 12, at least in part due to increased adhesion from one or more surface-treated surfaces of the structural support member 20. As another example, such as Figure 3 As shown in section 30, the structural support member 20 can support the connection 32 between the sections 34 of the outer sheath 24 to resist buckling near the connection 32. As another example, such as... Figure 4 As shown in section 40, the structural support member 20 can provide greater flexibility along the duct body 12. As another example, such as... Figure 5A As shown in section 50, the outer sheath 24 can provide greater flexibility and / or compressibility variation while maintaining a relatively constant inner and outer diameter of the catheter body 12. In these various ways, the catheter body 12 can increase the flexibility and / or maneuverability of the catheter 10 through the patient's tortuous vascular system. Any instance of catheter body 12 properties that contribute to resistance to kinking or flexion can be used in combination with each other.

[0155] Once the distal end 12B of the catheter body 12 is positioned at the target tissue site, which may be close to the thromboembolic material (e.g., a thrombus), the thromboembolic material is removed from the vascular system through the catheter body 12. For example, the thromboembolic material can be aspirated from the vascular system by applying a vacuum force to the inner lumen 26 of the catheter body 12 at least through the hub 14 (and / or proximal end 12A), which can cause the thromboembolic material to be introduced into the inner lumen 26 through the distal opening 13. Optionally, vacuum or aspiration can continue to aspirate the thromboembolic material proximally along the inner lumen 26, reaching all or part of the proximal end 12A or hub 14. As a further option, aspiration or vacuum may cause the thromboembolic material to adhere to or be attached to the distal tip; in this case, the catheter 10 or catheter body 12 and the thromboembolic material can be removed from the vascular system as a unit, for example, through another catheter surrounding the catheter 10 or catheter body 12.

[0156] As another example, thromboembolic material can be removed from the vascular system using another technique, such as an intravascular retraction device delivered through the lumen 26 of the catheter body 12. In this method, the catheter body 12 can be inserted into the vascular system (e.g., using any technique disclosed herein), and the retraction device advances through the lumen 26 (or through another catheter, such as a microcatheter, inserted into the vascular system through the lumen 26) such that the device engages with the thromboembolic material. The retraction device and the material thereby engaged (along with any other catheter or microcatheter) can then be retracted into the lumen 26 and removed from the patient. Optionally, aspiration can be performed using or through the catheter body 12 during the retraction of the retraction device and the thromboembolic material back into the catheter body 12. The vascular system may include a neurovascular system, a peripheral vascular system, or a cardiac vascular system. The thromboembolic material can be located using any suitable technique, such as fluorescence microscopy, intravascular ultrasound, or carotid Doppler imaging.

[0157] Various aspects of this disclosure have been described. These and other aspects are within the scope of the following claims.

Claims

1. A catheter comprising: Inner liner; An outer sheath, the outer sheath comprising a plurality of outer sheath sections and one or more connecting portions located between the outer sheath sections; as well as A structural support member, the structural support member being positioned between at least a portion of the inner bushing and at least a portion of the outer sheath. The first portion of the structural support member has a first density, and the second portion of the structural support member has a second density less than the first density. The first portion of the structural support member is located near the connection between the outer sheath segments. The surface of the first portion of the structural support member is surface-treated to increase adhesion of the surface to at least one of the inner liner or the outer sheath and to resist separation of the inner liner, the outer sheath, or two or more of the structural support members in response to bending or compressive forces on the conduit. The second portion of the structural support member is not surface-treated, or the degree of surface treatment is less than that of the first portion of the structural support member.

2. The conduit according to claim 1, wherein the structural support member is surface-treated on its inner radial surface but not on its outer radial surface.

3. The conduit according to claim 1, wherein the structural support member is surface-treated on its outer radial surface but not on its inner radial surface.

4. The conduit according to claim 1, wherein the surface roughness of at least a portion of the surface of the structural support member is greater than 2 micrometers Ra.

5. The catheter of claim 1, wherein at least a portion of the surface of the structural support member is covalently bonded to at least one of the inner liner or the outer sheath.

6. The catheter of claim 1, wherein at least a portion of the surface of the structural support member comprises a coating covalently bonded to at least one of the inner liner or the outer sheath.

7. The conduit according to claim 1, wherein the structural support member comprises a coiled structural support member.

8. The conduit according to claim 7, wherein the first portion of the coiled structure support member has a first coil pitch, and the second portion of the coiled structure support member has a second coil pitch smaller than the first coil pitch.

9. The conduit of claim 8, wherein the surface treated includes a first surface of the first portion of the coiled structure support member, and wherein the second surface of the second portion of the coiled structure support member is not surface treated.

10. The conduit of claim 8, wherein the surface-treated surface includes a first surface of the first portion of the coiled structure support member having a first surface roughness, and wherein the second surface of the second portion of the coiled structure support member has a second surface roughness less than the first surface roughness.

11. The conduit of claim 8, wherein the shear strength of the first portion is greater than twice the shear strength of the structural support member without surface treatment.

12. The conduit of claim 7, wherein the first portion of the coiled structure support member has a first diameter, and the second portion of the coiled structure support member has a second diameter greater than the first diameter.

13. The catheter according to claim 1, wherein the structural support member comprises a braided structural support member.

14. A catheter comprising: Inner liner; An outer sheath, the outer sheath comprising a plurality of outer sheath sections and one or more connecting portions located between the outer sheath sections; A support layer, the support layer being positioned between at least a portion of the inner liner and at least a portion of the outer sheath; as well as A structural support member, the structural support member being positioned between at least a portion of the inner bushing and at least a portion of the outer sheath. The first portion of the structural support member has a first density, and the second portion of the structural support member has a second density less than the first density. The first portion of the structural support member is located near the connection between the outer sheath segments. The surface of the first portion of the structural support member is surface-treated to increase adhesion of the surface to at least one of the inner liner, the outer sheath, or the support layer, and to resist separation of the inner liner, the outer sheath, or two or more of the structural support members in response to bending or compressive forces on the conduit. The second portion of the structural support member is not surface-treated, or the degree of surface treatment is less than that of the first portion of the structural support member.

15. The catheter of claim 14, wherein at least a portion of the support layer is positioned between the structural support member and the outer sheath.

16. The catheter of claim 14, wherein at least a portion of the surface of the structural support member is covalently bonded to at least one of the inner liner, the outer sheath, or the support layer.

17. The catheter of claim 14, wherein at least a portion of the surface of the structural support member comprises a coating covalently bonded to at least one of the inner liner, the outer sheath, or the support layer.

18. The conduit of claim 14, wherein the structural support member comprises a coiled structural support member, and wherein a first portion of the coiled structural support member has a first coil pitch, and a second portion of the coiled structural support member has a second coil pitch smaller than the first coil pitch.

19. The conduit of claim 18, wherein the surface treated includes a first surface of the first portion of the coiled structure support member, and wherein the second surface of the second portion of the coiled structure support member is not surface treated.

20. The conduit of claim 18, wherein the surface-treated surface includes a first surface of the first portion of the coiled structure support member having a first surface roughness, and wherein the second surface of the second portion of the coiled structure support member has a second surface roughness less than the first surface roughness.

Images