Elastic strain relief for catheters

Abstract

A medical device is configured to be flexible and maintain kink resistance while also reducing strain fracture. The medical device may include an elongated tubular shaft (12) defining a lumen (40) extending from a proximal portion to a distal portion. The elongated tubular shaft (12) includes an outer sheath (34) forming an outer surface of the elongated tubular shaft (12); a support member (36) including at least one filament (38) extending in a helical configuration along at least a portion of the length of the elongated tubular shaft (12); and a strain relief layer (32) including a material having an elastic modulus less than the elastic modulus of the outer sheath (34), the strain relief layer (32) being positioned at least between adjacent windings of the support member (36). The strain relief layer (32) and the support member (36) together form an inner surface of the elongated tubular shaft (12).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Application No. 62 / 899,844, filed on September 13, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates generally to medical devices and, more particularly, to catheters having strain relief layers. Background Art

[0004] A wide variety of in vivo medical devices have been developed for medical uses, such as surgical and / or intravascular use. Some of these devices include guidewires, catheters, medical device delivery systems (e.g., for stents, grafts, replacement valves, etc.), etc. These devices are manufactured by any of a variety of different manufacturing methods and can be used according to any of a variety of methods. There is a need to provide alternative medical devices and alternative methods for manufacturing and / or using medical devices. Summary of the invention

[0005] The present invention relates to several alternative designs, materials, and methods of manufacturing medical device structures and components.

[0006] In a first example, a medical device may include an elongated tubular shaft defining a lumen extending from a proximal portion to a distal portion. The elongated tubular shaft may include an outer sheath forming an outer surface of the elongated tubular shaft; a support member including at least one filament extending in a helical configuration along at least a portion of the length of the elongated tubular shaft; and a strain relief layer including a material having an elastic modulus less than the elastic modulus of the outer sheath. The strain relief layer may be positioned at least between adjacent windings of the support member. The strain relief layer and the support member may together form an inner surface of the elongated tubular shaft.

[0007] Alternatively or additionally to any of the above examples, in another example, the thickness of the strain relief layer may be approximately equal to the thickness of the at least one filament in a radial direction.

[0008] Alternatively or additionally to any of the above examples, in another example, the thickness of the outer sheath can be substantially uniform over the length of the elongated tubular shaft.

[0009] Alternatively or additionally to any of the above examples, in another example, a strain relief layer may also be disposed on a radially outward surface of at least one filament.

[0010] Alternatively or additionally to any of the above examples, in another example, the thickness of the outer sheath can be variable over the length of the elongated tubular shaft.

[0011] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can have a substantially uniform thickness along the length of the elongated tubular shaft.

[0012] Alternatively or additionally to any of the above examples, in another example, the support member may include two or more filaments that are braided to form a braid.

[0013] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastomeric material.

[0014] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastic polyurethane.

[0015] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastomeric polyether block amide.

[0016] Alternatively or additionally to any of the above examples, in another example, the outer jacket may include polyamide.

[0017] Alternatively or additionally to any of the above examples, in another example, the outer jacket can include a polyether block amide having a hardness of about 63D or greater.

[0018] Alternatively or additionally to any of the above examples, in another example, the support member may include a metal or a metal alloy.

[0019] Alternatively or additionally to any of the above examples, in another example, the support member may include a non-metallic material.

[0020] Alternatively or additionally to any of the above examples, in another example, the distal portion of the elongated tubular shaft can have greater flexibility than the proximal portion of the elongated tubular shaft.

[0021] In another example, a medical device may include an elongated tubular shaft defining a lumen extending from a proximal portion to a distal portion. The elongated tubular shaft may include an outer sheath forming an outer surface of the elongated tubular shaft; a support member including at least one filament extending in a helical configuration along at least a portion of the length of the elongated tubular shaft; and a strain relief layer including a material having an elastic modulus less than the elastic modulus of the outer sheath. The strain relief layer may be positioned at least between adjacent windings of the support member. The strain relief layer and the support member may together form an inner surface of the elongated tubular shaft.

[0022] Alternatively or additionally to any of the above examples, in another example, the thickness of the strain relief layer may be approximately equal to the thickness of the at least one filament in a radial direction.

[0023] Alternatively or additionally to any of the above examples, in another example, the thickness of the outer sheath can be substantially uniform over the length of the elongated tubular shaft.

[0024] Alternatively or additionally to any of the above examples, in another example, a strain relief layer may also be disposed on a radially outward surface of at least one filament.

[0025] Alternatively or additionally to any of the above examples, in another example, the thickness of the outer sheath can be variable over the length of the elongated tubular shaft.

[0026] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can have a substantially uniform thickness along the length of the elongated tubular shaft.

[0027] Alternatively or additionally to any of the above examples, in another example, the support member may include two or more filaments that are braided to form a braid.

[0028] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastomeric material.

[0029] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastic polyurethane.

[0030] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastomeric polyether block amide.

[0031] Alternatively or additionally to any of the above examples, in another example, the outer jacket may include polyamide.

[0032] Alternatively or additionally to any of the above examples, in another example, the outer jacket can include a polyether block amide having a hardness of about 63D or greater.

[0033] In another example, a medical device may include an elongated tubular shaft defining a lumen extending from a proximal portion to a distal portion. The elongated tubular shaft may include an outer sheath forming an outer surface of the elongated tubular shaft and having a thickness that is substantially uniform over the length of the elongated tubular shaft; a support member including at least one filament extending in a helical configuration along at least a portion of the length of the elongated tubular shaft; and a strain relief layer including a material having an elastic modulus that is less than the elastic modulus of the outer sheath. The strain relief layer may be positioned at least between adjacent windings of the support member and have a thickness that is approximately equal to the thickness of the at least one filament in a radial direction. The strain relief layer and the support member may together form an inner surface of the elongated tubular shaft.

[0034] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastic polyurethane.

[0035] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastomeric polyether block amide.

[0036] Alternatively or additionally to any of the above examples, in another example, the outer jacket can include a polyamide or polyether block amide having a hardness of about 63D or greater.

[0037] In another example, a medical device may include an elongated tubular shaft defining a lumen extending from a proximal portion to a distal portion. The elongated tubular shaft may include an outer sheath forming an outer surface of the elongated tubular shaft and having a variable thickness over the length of the elongated tubular shaft; a support member including at least one filament extending in a helical configuration along at least a portion of the length of the elongated tubular shaft; and a strain relief layer including a material having an elastic modulus less than the elastic modulus of the outer sheath. The strain relief layer may be positioned at least between adjacent windings of the support member and on a radially outward surface of at least one filament. The strain relief layer and the support member may together form an inner surface of the elongated tubular shaft.

[0038] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastic polyurethane.

[0039] Alternatively or additionally to any of the above examples, in another example, the strain relief layer can include an elastomeric polyether block amide.

[0040] Alternatively or additionally to any of the above examples, in another example, the outer jacket can include a polyamide or polyether block amide having a hardness of about 63D or greater.

[0041] The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1A is a partial cross-sectional view of the reinforced catheter;

[0043] Figure 1B is Figure 1A Schematic finite element analysis (FEA) of strain in a reinforced conduit;

[0044] Figure 1C is Figure 1A Schematic finite element analysis (FEA) of stresses in a reinforced conduit;

[0045] Figure 2 is a plan view of a medical device according to one embodiment of the present invention;

[0046] Figure 3 yes Figure 2 A partial cross-sectional view of the medical device taken along line 3-3;

[0047] Figure 4A is Figure 3 Schematic finite element analysis (FEA) of strain in a slender tubular shaft;

[0048] Figure 4B is Figure 3 Schematic finite element analysis (FEA) of stresses in a slender tubular shaft;

[0049] Figure 5 is a partial cross-sectional view of another illustrative medical device;

[0050] Fig. 6A is Figure 5 Schematic finite element analysis (FEA) of strain in a slender tubular shaft; and

[0051] Figure 6B is Figure 5 Schematic finite element analysis (FEA) of stresses in a slender tubular shaft. DETAILED DESCRIPTION

[0052] For the following defined terms, these definitions shall apply unless a different definition is given in the claims or elsewhere in this specification.

[0053] All numerical values ​​are assumed herein to be modified by the term "about", whether or not expressly indicated. The term "about" generally refers to a range of numbers that one skilled in the art considers equivalent to the referenced value (i.e., having the same function or result). In many cases, the term "about" may mean including numbers rounded to the nearest significant figure.

[0054] The recitation of numerical ranges by endpoints includes all numbers within that range (eg, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0055] Although some suitable sizes, ranges and / or values ​​are disclosed for various components, features and / or specifications, those skilled in the art to which the present invention relates will understand that the desired sizes, ranges and / or values ​​may be derived from those explicitly disclosed.

[0056] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise.

[0057] The following detailed description should be read with reference to the accompanying drawings, in which similar elements in different drawings have the same numbering. The specific embodiments and the drawings, which are not necessarily drawn to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments shown are intended to be exemplary only. The selected features of any illustrative embodiment may be incorporated into another embodiment unless expressly indicated to the contrary.

[0058] As used herein, the terms "proximal" and "distal" are intended to refer to directions toward (proximal) and away from (distal) a user of the device.

[0059] To achieve the desired flexibility and maintain kink resistance in a thin-walled polymer catheter, the catheter (or other elongated tubular shaft) may be reinforced with a high modulus component (such as, but not limited to, a coil or braid) to increase its hoop strength. Figure 1A is a partial cross-sectional view of an illustrative catheter 1 having an elongated tubular shaft 2 and a high modulus component 4. The high modulus component 4 can be laminated into the wall of the elongated tubular shaft 2, which can allow for a smaller bend radius before kinking. However, the high modulus component 4 can create a failure mode in which the side of the catheter wall that is under the highest tension and greatest strain breaks. Figure 1B is Figure 1A Schematic finite element analysis (FEA) of strain in one side of catheter 1. Figure 1C is Figure 1A Schematic finite element analysis (FEA) of stresses in one side of the conduit 1. Figure 1B and Figure 1C As can be seen in the figure, the highest strain 6 in the elongated tubular shaft 2 is at the upper corner of the high modulus component 4, and the highest stress 8 in the elongated tubular shaft 2 is at the corner of the high modulus component 4. Other high strain regions 7 may appear within the elongated tubular shaft 2. Region 7 may be at the lower corner of the high modulus component 4, in the space between adjacent windings of the high modulus component, etc. However, in some cases, the beginning of fracture may occur at the stress angle 8, where the polymer is laminated to the coil or braid. This may be caused by significant differences in material properties (e.g., Young's modulus) at the geometry (e.g., sharp corners) and / or transition points. In some cases, the occurrence of fracture may increase with the notch sensitivity of the polymer (e.g., the degree to which the material is prone to fracture in the presence of surface inhomogeneities, which may include changes in the material). Brittle materials may have higher notch sensitivity than more ductile materials. What may be needed is a slender tubular shaft that is flexible and maintains kink resistance while also reducing strain fracture.

[0060] Figure 2 1 is a plan view of an illustrative medical device 10, for example, a catheter. The medical device 10 can be any of a variety of different catheters. In some embodiments, the medical device 10 can be an intravascular catheter. Examples of intravascular catheters include balloon catheters, plaque removal catheters, drug delivery catheters, diagnostic catheters, and guide catheters. However, the medical device 10 can take the form of other suitable guides, diagnostic or therapeutic devices (including catheters, endoscopic instruments, laparoscopic instruments, etc.), and it can be suitable for use at other locations and / or body cavities in the patient's body. The medical device 10 can be sized according to its intended use. For example, the medical device 10 can have a length in the range of about 50 to about 200 centimeters, about 75 to about 175 centimeters, or about 100 to about 150 centimeters. It is also conceivable that the diameter of the medical device 10 can vary based on the application of use.

[0061] In the illustrated embodiment, the medical device 10 may include an elongated tubular shaft 12 having a proximal portion 14, a distal portion 16 terminating at a distal end 28, and an intermediate region 30 disposed between the proximal portion 14 and the distal portion 16. The elongated tubular shaft 12 may extend proximally from the distal end 28 to the proximal portion 14, and the proximal portion 14 may be configured to remain outside the patient's body. Depending on the application of use, a hub and strain relief assembly 18 may be connected to the proximal portion 14 of the elongated tubular shaft 12. The hub and strain relief assembly 18 may include a main body portion 20 for connecting other treatment devices or providing a port for facilitating other treatments and a strain relief piece 24 intended to reduce kinking. The hub and strain relief assembly 18 may also include a pair of flanges 22. The hub and strain relief assembly 18 may be of conventional design and may be attached using conventional techniques. Other hubs and / or handles may replace the hub and strain relief assembly 18 for different use cases.

[0062] Although not explicitly shown, the elongated tubular shaft 12 may include one or more shaft segments having different degrees of flexibility. In some cases, the elongated tubular shaft 12 may become progressively more flexible toward its distal end 28, however this is not required. It is contemplated that the stiffness and size of the elongated tubular shaft 12 may be modified for use in various locations within the body.

[0063] Figure 3 is Figure 2 3-3 of the elongated tubular shaft 12. The elongated tubular shaft 12 can be a generally tubular member defining a lumen 40 through which a guidewire (not explicitly shown) or other medical device (not explicitly shown) or fluid can pass. The elongated tubular shaft 12 can include a strain relief layer 32 and an outer sheath 34. The support member 36 can be embedded or otherwise disposed within the strain relief layer 32. It is contemplated that the support member 36 can be incorporated into any portion of the elongated tubular shaft 12 as desired. For example, the support member 36 can be incorporated into the entire length of the elongated tubular shaft 12, the proximal portion 14, the intermediate portion 30, the distal portion 16, or a combination thereof.

[0064] The support member 36 may be a reinforcement layer configured to provide kink resistance while maintaining desired flexibility. In some embodiments, the support member 36 may be a helically wound coil, such as Figure 3 In other embodiments, support member 36 may take the form of a braid or other support member. Support member 36 may be formed of any suitable material, including metals and metal alloys, such as, but not limited to, nitinol, stainless steel, tungsten, gold, titanium, silver, copper, platinum, or iridium. Support member 36 may also be formed of non-metallic materials, such as (poly(p-phenylene terephthalamide)) fibers, LCP (liquid crystal polymer) fibers, glass fibers, etc. In at least some embodiments, part or all of the support member 36 may include a radiopaque material. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymer materials loaded with radiopaque fillers, etc.

[0065] In some embodiments, a certain degree of MRI compatibility can be imparted. For example, in order to enhance compatibility with magnetic resonance imaging (MRI) machines, it may be desirable to manufacture the support member 36 or other portions thereof in a manner that will impart a certain degree of MRI compatibility. For example, the support member 36 or portions thereof may be made of a material that does not substantially distort the image and create a large number of artifacts (gaps in the image). For example, certain ferromagnetic materials may be unsuitable because they may create artifacts in the MRI image. The support member 36 or portions thereof may also be made of a material that the MRI machine is capable of imaging. Some materials that exhibit these properties include, for example, tungsten, Elgiloy, MP35N, Nitinol, etc.

[0066] It is contemplated that the support member 36 may include a wire, ribbon, or filament 38 wound into a spiral configuration. When so provided, a braid may be formed by weaving or plaiting two or more filaments 38 together. Each filament 38 of the braid may extend in a generally spiral configuration, with portions being above or below another filament 38. It is contemplated that the support member 36 may be formed from a single filament 38 or multiple filaments 38, as desired. In some cases, multiple filaments 38 may be wound together to function as a single filament. The filaments 38 may have any cross-sectional shape desired, such as, but not limited to, rectangular, circular, square, triangular, oblong, polygonal, and the like. The filaments 38 may be wound so that the support member 36 has an open pitch, a closed pitch, or a combination thereof. For example, Figure 3 The filaments 38 are shown arranged so that there is a space 42 between adjacent windings (e.g., adjacent windings do not touch). An open pitch configuration can be defined as a space between adjacent windings of the filament 38 (e.g., such as between Figure 3 42 between windings on the same side of the tubular shaft 12). The absence of spaces between windings can be referred to as a closed pitch configuration. A closed pitch configuration may be desired to provide increased column strength to a given component of a medical device. In addition, characteristics such as filament cross-sectional size and / or shape, material, orientation, and spacing may contribute to the overall configuration and performance of the support member 36 (e.g., flexibility, pushability, trackability, column stiffness, etc.).

[0067] The strain relief layer 32 can be disposed between adjacent windings of the support member 36 such that the strain relief layer 32 and the support member 36 together define or form the inner surface of the elongated tubular shaft 12. For example, the support member 36 can be formed by winding (or braiding) the filaments 38 on a mandrel. The strain relief layer 32 can be applied between adjacent windings of the support member 36. When the strain relief layer 32 is applied between adjacent windings of the support member 36, the strain relief layer 32 can be discontinuous along the plane of the longitudinal axis of the elongated tubular shaft 12 or have a generally helical morphology.

[0068] It is contemplated that the strain relief layer 32 may be applied so as to achieve a substantially uniform thickness with the support member 36. For example, the strain relief layer 32 may have a thickness 46 that is substantially equal to the thickness 48 of the filaments 38 in the radial direction. It is contemplated that having a uniform layer (e.g., the support member 36 and the strain relief layer 32) may increase the uniformity of the outer jacket 34 over which the outer jacket 34 is to be applied. Increasing the uniformity of the outer jacket 34 may reduce local strain. In other words, strain across the outer jacket 34 may reduce stress in the outer jacket 34 because the uniform thickness 50 of the outer jacket 34 may result in elongation over the entire length of the outer jacket 34, rather than having a shorter area (or reduced thickness) experience the majority of the elongation (as may occur if the outer jacket 34 is applied directly to the support member 36).

[0069] The strain relief layer 32 can be formed of a material having an elastic modulus that is less than the elastic modulus of the outer jacket 34. In other words, the outer jacket 34 can be stiffer than the strain relief layer 32. In some cases, the strain relief layer 32 can be formed of an elastomeric material. It can be believed that elastomeric materials are capable of large and reversible elastic deformations. Some illustrative elastomeric materials can include, but are not limited to, polyurethane elastomers, elastomeric polyether block amides (e.g., elastomers). Its hardness is in the range of about 25D), polysiloxane (e.g., silicone), styrene-butadiene copolymer, elastomeric polyamide, acrylonitrile-butadiene copolymer, chloroprene, natural polyisoprene, etc. The strain relief layer 32 can be highly flexible. It is contemplated that when formed from a flexible elastomeric material, the strain relief layer 32 can handle high strain rates without breaking at stress steps caused by the geometry (e.g., at the corner 52 of the filament 38 that contacts the outer sheath 34). In addition, as described herein, the strain relief layer 32 can smooth the transition geometry between the support member 36 and the outer sheath 34. These features can create effective strain relief between the support member 36 and the outer sheath 34, thereby reducing the local strain seen by the outer sheath 34. This can significantly improve the bending radius that the slender tubular shaft 12 can achieve before breaking.

[0070] The outer sheath 34 can have a substantially uniform diameter along the length of the elongated tubular shaft 12. The outer sheath 34 can be formed of one or more polymers and / or plastic materials along its length or thickness. Some illustrative materials can include, but are not limited to, polyether block amides (e.g., having a hardness in the range of 63D or greater), polyamides, polyurethanes, polyester / ethers, polyoxymethylenes, blends, other high modulus polymers, and the like. In some cases, the outer sheath 34 can include two materials with different material properties (e.g., hardness, tensile strength, etc.). It should also be understood that the outer sheath 34 can include materials other than polymers or plastics. For example, the outer sheath 34 can include polymers, metals, ceramics, composite materials, combinations thereof, and the like.

[0071] The outer jacket 34 can be formed over or on top of the strain relief layer 32 and support member 36 such that the inner diameter of the outer jacket 34 is approximately equal to the outer diameter of the strain relief layer 32 and support member 36. For example, the outer jacket 34 can be co-extruded over the strain relief layer 32 and support member 36, or it can be preformed and then heat shrunk into place to form the outer surface of the elongated tubular shaft 12.

[0072] Optionally, the medical device 10 may include a coating, such as a lubricious coating, on part or all of the outer surface of the medical device 10 and / or the inner surface of the cavity 40. Suitable lubricious polymers are well known in the art and may include hydrophilic polymers such as polyarylene oxides, polyvinyl pyrrolidones, polyvinyl alcohols, hydroxyalkyl celluloses, algins, sugars, caprolactones, and the like, as well as mixtures and combinations thereof. The hydrophilic polymers may be mixed with one another or with a defined amount of a water-insoluble compound (including some polymers) to produce a coating having suitable lubricity, adhesion, and solubility.

[0073] Figure 4A yes Figure 3 Schematic finite element analysis (FEA) of strain in an elongated tubular shaft 12 including a strain relief layer 32, an outer jacket 34, and a high modulus support member 36. Figure 4B yes Figure 3 Schematic FEA of stress in an elongated tubular shaft 12 including a strain relief layer 32, an outer jacket 34, and a high modulus support member 36. Figure 4A As can be seen in FIG. 6 , the highest strain 60 generally occurs in the strain relief layer 32 (e.g., the elastomer layer). Figure 4B As can be seen in FIG. 6 , the highest stresses 62 generally occur within the outer jacket 34 along the radially outward surface 41 of the support member 36 . Figure 4A and Figure 4BIt is shown that the strain relief between the support member 36 and the outer jacket 34 is obtained by reducing the local strain in the outer jacket 34. This is different from the Figure 1A The local strains shown in the FEA of catheter 1 (e.g., Figure 1B This is contrasted with the high strain region shown in 8).

[0074] Figure 5 It can be used for Figure 2 1 is a partial longitudinal cross-sectional view of another illustrative elongated tubular shaft 100 in a medical device 10 of FIG. The elongated tubular shaft 100 can be a generally tubular member defining a lumen 102 through which a guidewire (not explicitly shown) or other medical device (not explicitly shown) can pass. The elongated tubular shaft 100 can include a strain relief layer 104 and an outer sheath 106. A support member 108 can be embedded or otherwise disposed within the strain relief layer 104. It is contemplated that the support member 108 can be incorporated into any portion of the elongated tubular shaft 100 as desired. For example, the support member 108 can be incorporated into the entire length of the elongated tubular shaft 100, the proximal portion, the middle portion, the distal portion, or a combination thereof.

[0075] The support member 108 may be a helically wound coil, such as Figure 5 In other embodiments, the support member 108 may take the form of a braid or other support member. The support member 108 may be formed of any suitable material, including metals and metal alloys, such as, but not limited to, nitinol, stainless steel, tungsten, gold, titanium, silver, copper, platinum, or iridium. The support member 108 may also be formed of non-metallic materials, such as (poly(p-phenylene terephthalamide)) fibers, LCP (liquid crystal polymer) fibers, glass fibers, etc. In at least some embodiments, part or all of the support member 108 may include a radiopaque material. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymer materials loaded with radiopaque fillers, etc.

[0076] In some embodiments, a certain degree of MRI compatibility can be imparted. For example, in order to enhance compatibility with magnetic resonance imaging (MRI) machines, it may be desirable to manufacture the support member 108 or other portions thereof in a manner that will impart a certain degree of MRI compatibility. For example, the support member 108 or portions thereof may be made of a material that does not substantially distort the image and create a large number of artifacts (gaps in the image). For example, certain ferromagnetic materials may be unsuitable because they may create artifacts in the MRI image. The support member 108 or portions thereof may also be made of a material that the MRI machine is capable of imaging. Some materials that exhibit these properties include, for example, tungsten, Elgiloy, MP35N, Nitinol, and the like.

[0077] It is contemplated that the support member 108 may include a wire, ribbon or filament 110 wound into a coiled configuration. The filament 110 may have any desired cross-sectional shape, such as, but not limited to, rectangular, circular, square, triangular, rectangular, polygonal, etc. The filament 110 may be wound so that the support member 108 has an open pitch, a closed pitch, or a combination thereof. In addition, characteristics such as filament cross-sectional size and / or shape, material, orientation, and spacing may contribute to the overall configuration and performance (e.g., flexibility, pushability, trackability, column stiffness, etc.) of the support member 108.

[0078] The strain relief layer 104 can be disposed between adjacent windings of the support member 108 and on the radially outward surface 112 of the support member 108, such that the strain relief layer 104 has a substantially uniform thickness along the length of the elongated tubular shaft 100. The strain relief layer 104 can be disposed between adjacent windings of the support member 108, such that the strain relief layer 104 and the support member 108 together define or form the inner surface of the elongated tubular shaft 100. For example, the support member 108 can be formed by winding (or braiding) the filament 110 on a mandrel. The strain relief layer 104 can be applied between adjacent windings of the support member 112 and on the radially outward surface 112 thereof. When the strain relief layer 104 is applied between adjacent windings and on the radially outward surface 112 of the support member 108, the strain relief layer 104 can be a substantially continuous layer along the plane of the longitudinal axis of the elongated tubular shaft 100. In some cases, the strain relief layer 104 can be applied as a separate layer in an extrusion or solution coating process. In other embodiments, the strain relief layer 104 may be formed by reflowing a dual layer extrusion onto the support member 108 .

[0079] It is contemplated that the strain relief layer 104 may be applied so as to achieve a substantially uniform thickness 114 along its length. The strain relief layer 104 may be formed of an elastomeric material. It is believed that elastomeric materials are capable of achieving large and reversible elastic deformations. Some illustrative elastomeric materials may include, but are not limited to, urethane elastomers, elastomeric polyether block amides (e.g., elastomers ), polysiloxane (e.g., silicone), styrene-butadiene copolymers, elastomeric polyamides, acrylonitrile-butadiene copolymers, chloroprene, natural polyisoprene, and the like. The strain relief layer 104 can be highly flexible. It is contemplated that when formed from a flexible elastomeric material, the strain relief layer 104 can handle high strain rates without breaking at stress risers induced by geometry (e.g., at corners 116 of the filaments 110 that contact the outer sheath 106). In addition, the strain relief layer 104 can smooth the transition geometry between the support member 108 and the outer sheath 106. These features can create effective strain relief between the support member 108 and the outer sheath 106, thereby reducing the local strain seen by the outer sheath 106. This can significantly improve the bend radius that the elongated tubular shaft 100 can achieve before breaking.

[0080] The outer sheath 106 can have a varying thickness along the length of the elongated tubular shaft 100. For example, the outer sheath 106 can be thinner on the support member 108 than in other areas. The outer sheath 106 can be formed by one or more polymers and / or plastic materials along its length or thickness. Some illustrative materials may include, but are not limited to, polyether block amides (e.g., having a hardness in the range of 63D or greater), polyamides, polyurethanes, polyester / ethers, polyoxymethylenes, blends, other high modulus polymers, and the like. In some cases, the outer sheath 106 may include two materials with different material properties (e.g., hardness, tensile strength, etc.). It should also be understood that the outer sheath 106 may include materials other than polymers or plastics. For example, the outer sheath 106 may include polymers, metals, ceramics, composite materials, combinations thereof, and the like.

[0081] The outer jacket 106 can be formed over or on top of the strain relief layer 104 and the support member 108 such that the inner diameter of the outer jacket 106 is approximately equal to the outer diameter of the strain relief layer 104 and the support member 108. For example, the outer jacket 106 can be co-extruded over the strain relief layer 104 and the support member 108, or it can be preformed and then heat shrunk into place to form the outer surface of the elongated tubular shaft 100.

[0082] Fig. 6A yes Figure 5 Schematic finite element analysis (FEA) of strain in an elongated tubular shaft 100 including a strain relief layer 104, an outer jacket 106, and a high modulus support member 108. Figure 6B yes Figure 5 Schematic FEA of stress in an elongated tubular shaft 100 comprising Figure 5 The strain relief layer 104, the outer jacket 106 and the high modulus support member 108. Fig. 6AAs can be seen in FIG. 1 , the highest strain 120 generally occurs in the strain relief layer 104 (eg, the elastomer layer). Figure 6B As can be seen in the figure, the high stresses have been significantly reduced, which FEA does not show in Figure 1A The highest stress level is shown in the embodiment shown. Fig. 6A and Figure 6B It is shown that strain relief between the support member 108 and the outer jacket 106 is achieved by reducing local strain within the outer jacket 106 .

[0083] In some embodiments, the medical device 10, the elongated tubular shaft 12, 100, and / or components thereof can be made of metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, ceramics, combinations thereof, etc., or other suitable materials. Some examples of suitable metals and metal alloys include stainless steels, such as 444V, 444L, 314LV, and 17-7 stainless steel; mild steel; nickel-titanium alloys, such as linear elastic and / or superelastic nitinol; other nickel alloys, such as nickel-chromium-molybdenum alloys (e.g., UNS: N06625, such as 625, UNS: N06022, such as UNS: N10276, such as other alloys, etc.), nickel-copper alloys (e.g. UNS: N04400, such as 400、NICKEL 400, 400, etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R44035, such as MP35- etc.), nickel-molybdenum alloys (e.g., UNS: N10665, such as ), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, etc.; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R44003, such as etc.); platinum-rich stainless steel; titanium; platinum; palladium; gold; combinations thereof; etc. or any other suitable material.

[0084] In at least some embodiments, some or all of the medical device 10, the elongated tubular shaft 12, 100 and / or its components may also be doped with, made of or otherwise include a radiopaque material. Radiopaque materials are understood to be capable of producing a relatively bright image on a fluoroscopic screen or with another imaging technique during a medical procedure. This relatively bright image helps the user determine the position of the medical device 10, the elongated tubular shaft 12, 100 and / or its components, etc. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymer materials loaded with radiopaque fillers, etc. Additionally, other radiopaque marker bands and / or coils may also be incorporated into the design of the medical device 10, the elongated tubular shaft 12, 100 and / or its components, etc. to achieve the same results.

[0085] In some embodiments, a degree of magnetic resonance imaging (MRI) compatibility is imparted to the access and anchoring device, medical device 10, elongated tubular shaft 12, 100, and / or components thereof, and the like. For example, the medical device 10, elongated tubular shaft 12, 100, and / or components thereof may be made of a material that does not substantially distort the image and create a substantial amount of artifacts (e.g., gaps in the image). For example, certain ferromagnetic materials may be unsuitable because they may create artifacts in an MRI image. The medical device 10, elongated tubular shaft 12, 100, and / or components thereof may also be made of a material that is capable of being imaged by an MRI machine. Some materials that exhibit these properties include, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R44003, such as etc.), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R44035, such as MP35- etc.), Nitinol, etc.

[0086] In some embodiments, the medical device 10, the elongated tubular shaft 12, 100, and / or components thereof can be made of or include a polymer or other suitable material. Some examples of suitable polymers can include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., available from DuPont), polyoxymethylene (POM ... ), polyether block esters, polyurethanes (e.g., polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyether esters (e.g., available from DSM Engineering Plastics ), ether or ester based copolymers (e.g., butylene / poly(alkylene ether) phthalate and / or other polyester elastomers such as those commercially available from DuPont ), polyamide (e.g., available from Bayer Or available from Elf Atochem ), elastomeric polyamides, block polyamide / ethers, polyether block amides (PEBA, for example, available under the trade name commercially available), ethylene vinyl acetate copolymer (EVA), silicone, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low-density polyethylene (e.g., ), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS)), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g., ), polysulfone, nylon, nylon-12 (such as available from EMS American Grilon ), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefins, polystyrene, epoxy resins, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and / or SIBS 50A), polycarbonate, ionomers, biocompatible polymers, other suitable materials or mixtures, combinations, copolymers, polymer / metal composites, etc., thereof. In some embodiments, the sheath can be mixed with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6% LCP.

[0087] In some embodiments, the medical device 10, elongated tubular shaft 12, 100, and / or components thereof, etc., may include and / or perform treatment with a suitable therapeutic agent.

[0088] Those skilled in the art will recognize that the present invention may be embodied in many forms other than the specific embodiments described and contemplated herein. Accordingly, departures may be made in form and details without departing from the scope and spirit of the present invention as described in the following claims.

Claims

1. A medical device comprising: An elongated tubular shaft defining a lumen extending from a proximal portion to a distal portion, the elongated tubular shaft comprising: an outer sheath forming an outer surface of the elongated tubular shaft; a support member comprising at least one filament extending in a helical configuration along the entire length of the elongated tubular shaft; and a strain relief layer comprising a material having a modulus of elasticity less than the modulus of elasticity of the outer jacket, the strain relief layer being positioned at least between adjacent windings of the support member; wherein the strain relief layer and the support member together form an inner surface of the elongated tubular shaft; wherein the outer sheath is in direct contact with the strain relief layer along the length of the elongated tubular shaft, and the outer sheath has a variable thickness over the length of the elongated tubular shaft, wherein the outer sheath is thinner over the support member than in other areas; Wherein the strain relief layer has a substantially uniform thickness along the length of the elongated tubular shaft.

2. The medical device of claim 1, wherein the thickness of the strain relief layer is approximately equal to the thickness of the at least one filament in a radial direction.

3. The medical device of claim 1, wherein the strain relief layer is further disposed on a radially outward surface of the at least one filament.

4. The medical device of any one of claims 1 to 3, wherein the support member comprises two or more filaments that are braided to form a braid.

5. The medical device of any one of claims 1 to 3, wherein the strain relief layer comprises an elastomeric material.

6. The medical device of any one of claims 1 to 3, wherein the strain relief layer comprises elastic polyurethane.

7. The medical device of any one of claims 1 to 3, wherein the strain relief layer comprises an elastomeric polyether block amide.

8. The medical device of any one of claims 1 to 3, wherein the outer sheath comprises polyamide.

9. The medical device of any one of claims 1 to 3, wherein the outer sheath comprises a polyether block amide having a hardness of 63D or greater.

10. The medical device of any one of claims 1 to 3, wherein the support member comprises a metal or a metal alloy.

11. The medical device of any one of claims 1 to 3, wherein the support member comprises a non-metallic material.

12. The medical device of any one of claims 1 to 3, wherein the distal portion of the elongated tubular shaft has greater flexibility than the proximal portion of the elongated tubular shaft.

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