Patent Description:
A wide variety of medical devices have been developed for intravascular use. Catheters, for example, are commonly used to facilitate navigation through and/or treatment within the anatomy of a patient. To direct the distal portion of the catheter to the correct location in the vasculature, a physician must apply longitudinal forces, and sometimes rotational forces (i.e., torsional forces), from the proximal end of the catheter. For the catheter shaft to transmit these forces from the proximal end to the distal end, the catheter must be sufficiently rigid to be pushed through the blood vessel (a property commonly referred to as "pushability"), yet flexible enough to navigate through the often tortuous bends in the blood vessel. The catheter may also require sufficient torsional stiffness to transmit the applied torque (a property commonly referred to as "torqueability"). A need exists for catheter shafts that accomplish a balance between longitudinal rigidity, torsional stiffness, and flexibility.

<CIT> describes a catheter having a distal tip section having a pre-shaped tip configuration. <CIT> describes a multi-layered catheter that may include four layers along a proximal portion and three layers along a distal portion. The layers may include a stainless steel coil and a stainless steel braid. <CIT> describes a catheter assembly that includes an outer catheter and an inner catheter. An inner catheter body of the inner catheter includes a flexible section connected to a tip, a physical property transition section, a first body section on the proximal side of the physical property transition section, and a second body section on the proximal side of the first body section. The second body section has greater flexural rigidity than the first body section and includes a reinforcing material layer. <CIT> describes a catheter body that includes a hollow coil whose inner and outer surfaces are coated with inner and outer resin layers, respectively. A resin tip is at a distal end of the catheter body. The catheter body and resin tip also include an embedded braid. Japanese Patent Application No. <CIT> describes a catheter including a coil provided with densely wound parts that function as an X-ray imaging marker. Japanese Patent Application No. <CIT> describes a catheter that includes a metal coil and a buckling preventative member <NUM> composed of a coil.

Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure.

Specifically, the invention describes a catheter, comprising an elongated shaft having a proximal portion and a distal portion, wherein an inner surface of the elongated shaft defines a lumen that extends distally from the proximal portion to an opening at a distal terminus of the distal portion; wherein the distal portion includes an inner polymer structure having a first portion and a second portion positioned distal of the first portion along the length of the inner polymer structure, wherein the first portion has a first stiffness and the second portion has a second stiffness less than the first stiffness; an outer polymer structure disposed around the inner polymer structure; and a coil wound around the inner polymer structure and disposed within the outer polymer structure, wherein a portion of the coil within the distal portion includes a first region, a second region distal to the first region, and a third region distal to the second region, wherein the first and third regions each have a tighter pitch than the second region. In some embodiments, the distal terminus of the second portion coincides with the opening at the distal terminus of the shaft. In some embodiments, the distal terminus of the second portion is distal to a distal terminus of the coil. In some embodiments, a distal terminus of the second portion is proximal to a distal terminus of the coil. In some embodiments, the inner polymer structure includes a first layer and a second layer surrounding the first layer, and wherein an inner surface of the first layer defines a portion of the lumen. In some embodiments, the inner polymer structure includes a first layer and a second layer surrounded by the first layer, and wherein the first and second portions together comprise the first layer. In some embodiments, the catheter further includes a radiopaque marker positioned around the inner polymer structure, the outer polymer structure, or both the inner polymer structure and the outer polymer structure. In some embodiments, the thickness of each of the inner polymer structure and the outer polymer structure are constant along the length of the distal portion. In some embodiments, a thickness of at least one of the inner polymer structure and the outer polymer structure tapers along the length of the distal portion. In some embodiments, the first portion is made of a first material and the second portion is made of a second material different than the first material; wherein the distal portion further comprises a radiopaque band positioned around a portion of the inner polymer structure; and wherein the outer polymer structure is disposed around the inner polymer structure and the radiopaque band. In one embodiment, the inner polymer structure may include a first layer and a second layer surrounding the first layer, wherein an inner surface of the second layer defines a portion of the lumen. In another embodiment, the inner polymer structure may include a first layer and a second layer surrounded by the first layer, and wherein the first and second portions together comprise the first layer. Specific details of several embodiments of catheter devices, systems, and methods in accordance with the present technology are described below with reference to <FIG>. With regard to the terms "distal" and "proximal" within this description, unless otherwise specified, the terms can reference a relative position of the portions of a catheter and/or an associated device with reference to an operator and/or a location in the vasculature. Also, the term "thickness" as used herein with respect to a particular material or layer refers to the perpendicular distance between the plane running through and generally parallel with the radially outermost surface of the particular material or layer and the plane running through and generally parallel with the radially innermost surface of the particular material or layer.

<FIG> is a side view of a catheter <NUM> configured in accordance with an embodiment of the present technology, and <FIG> is a cross-sectional side view of a portion of the catheter <NUM> shown in <FIG>. Referring to <FIG> together, the catheter <NUM> includes a handle assembly <NUM> and an elongated shaft <NUM> having a proximal portion 106a coupled to the handle assembly <NUM> and a distal portion 106b. The handle assembly <NUM> includes a hub <NUM> configured to facilitate connection to other devices (e.g., a syringe, a Y-adapter, etc.) and a transition portion <NUM> configured to provide strain relief at the proximal portion 106a. In other embodiments, the handle assembly <NUM> can have other suitable configurations based on the desired functions and characteristics of the catheter <NUM>.

The shaft <NUM> is a generally tubular member having an inner surface that defines a lumen <NUM> (<FIG>) extending from the proximal portion 106a of the shaft <NUM> to an opening <NUM> at the distal terminus of the distal portion 106b. In some embodiments, the shaft <NUM> can include a radiopaque marker <NUM> (<FIG>) surrounding the lumen <NUM> at or just proximal to the opening <NUM>. The lumen <NUM> is configured to slidably receive and facilitate the passage therethrough of one or more medical devices, such as guidewires, balloon catheters, implants, intrasaccular occlusion devices (e.g., coils, expandable cages, expandable meshes, etc.), infusion devices, stents and/or stent-grafts, intravascular occlusion devices, clot retrievers, implantable heart valves, and other suitable medical devices and/or associated delivery systems. Additionally, the lumen <NUM> is configured to receive one or more fluids therethrough, such as radiopaque dye, saline, drugs, and the like.

The size of the lumen <NUM> can vary, depending on the desired characteristics of the catheter <NUM>. For example, in some embodiments the shaft <NUM> can have an inner diameter (e.g., lumen diameter) between about <NUM> millimeters (about <NUM> inches) and about <NUM> millimeters (about <NUM> inches) (e.g., <NUM> millimeters (<NUM> inches), <NUM> millimeters (<NUM> inches, etc.), and in some embodiments between about <NUM> millimeters (about <NUM> inches) and <NUM> millimeters (about <NUM> inches) (e.g., <NUM> millimeters (<NUM> inches), etc.). In a particular embodiment, the inner diameter is between about <NUM> millimeters (about <NUM> inches) and about <NUM> millimeters (about <NUM> inches) (e.g., <NUM> millimeters (<NUM> inches, <NUM> millimeters (<NUM> inches, etc.). Although the shaft <NUM> shown in <FIG> has a generally round cross-sectional shape, it will be appreciated that the shaft <NUM> can include other cross-sectional shapes or combinations of shapes. For example, the cross-sectional shape of the shaft <NUM> can be oval, rectangular, square, triangular, polygonal, and/or any other suitable shape and/or combination of shapes.

The outer diameter of the shaft <NUM> can be the same or vary along its length. For example, in the embodiment shown in <FIG>, the shaft <NUM> has a first portion <NUM> with a first diameter, a tapered portion <NUM> with a diameter that decreases in a proximal to distal direction, and a second portion <NUM> with a second diameter less than the first diameter. The length of the tapered portion <NUM> can be between about <NUM> and about <NUM>. In some embodiments, the shaft <NUM> does not include a second portion <NUM> and the tapered portion <NUM> extends distally to the distal terminus of the shaft <NUM>. In other embodiments, the shaft <NUM> has an outer diameter that is generally constant along its length. Moreover, the length and/or outside diameter of the shaft <NUM> is generally selected for the desired use of the catheter <NUM>. For example, in those embodiments where the catheter <NUM> is configured as a guide catheter for enabling intravascular insertion and navigation, the outside diameter of the shaft <NUM> can be between about <NUM> millimeters (about <NUM> Fr) and about <NUM> millimeters (about <NUM> Fr). In those embodiments where the catheter <NUM> is configured as a microcatheter for use within small anatomies of the patient, the outside diameter of the shaft <NUM> can be between about <NUM> millimeters (about <NUM> Fr) and about <NUM> millimeters (about <NUM> Fr).

Many embodiments of the present technology are particularly useful in treating targets located in tortuous and narrow vessels, such as certain sites in the neurovascular system, the coronary vascular system, or the peripheral vascular system (e.g., the superficial femoral, popliteal, or renal arteries). Neurovascular target sites, such as sites in the brain, are often accessible only via a tortuous vascular path. Although some embodiments of the catheter <NUM> are described in terms of intravascular use, in other embodiments the catheter <NUM> may be suited for uses in the digestive system, soft tissues, and/or any other insertion into an organism for medical uses. For example, in some embodiments, the catheter <NUM> may be significantly shorter and used as an introducer sheath, while in other embodiments the catheter <NUM> may be adapted for other medical procedures.

In the embodiment shown in <FIG>, the elongated shaft <NUM> includes an inner polymer structure <NUM> and an outer polymer structure <NUM> surrounding at least a portion of the inner polymer structure <NUM>. The shaft <NUM> shown in <FIG> also has an inner braid <NUM> embedded in the outer polymer structure <NUM>, an outer braid <NUM> surrounding at least a portion of the inner braid <NUM>, and a coil <NUM> wrapped around at least a portion of the inner polymer structure <NUM>. Each of these subcomponents will now be described in greater detail.

Referring again to <FIG> together, the inner polymer structure <NUM> extends from the proximal portion 106a of the shaft <NUM> to a location within the distal portion 106b of the shaft <NUM>. For example, in the embodiment shown in <FIG>, the inner polymer structure <NUM> extends from the proximal portion 106a of the shaft <NUM> to the opening <NUM> at the distal terminus of the distal portion 106b (e.g., the entire length of the shaft <NUM> or substantially the entire length of the shaft <NUM>). In other embodiments, the inner polymer structure <NUM> extends along only a portion of the length of the shaft <NUM> and/or has a proximal and/or a distal terminus that does not correspond to a proximal terminus and/or a distal terminus, respectively, of the shaft <NUM>. The length of the inner polymer structure <NUM> can vary depending upon, for example, the length of the shaft <NUM> and the desired characteristics and functions of the catheter <NUM>.

The inner polymer structure <NUM> can be made of any suitable polymer (and/or combination of multiple polymers) and by any suitable process. Suitable polymers can include, for example, polyoxymethylene (POM), polybutylene terephthalate (PBT), polyether block ester, polyether block amide (PEBA), fluorinated ethylene propylene (FEP), polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyurethane, polytetrafluoroethylene (PTFE), polyether-ether ketone (PEEK), polyimide, polyamide, polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), polyether-ester, platinum, polymer/metal composites, etc., or mixtures, blends or combinations thereof, and may also include or be made up of a lubricious polymer having a low coefficient of friction. In some embodiments (not shown), the inner polymer structure <NUM> includes one or more metals or metal alloys and/or combinations thereof. In a particular embodiment, the inner polymer structure <NUM> does not include any polymer material and solely comprises a metal and/or metal alloy.

The inner polymer structure <NUM> can include a single layer of material or it can have two or more layers of the same or different materials. For example, in the embodiment shown in <FIG>, the inner polymer structure <NUM> includes a first layer <NUM> and a second layer <NUM> surrounding at least a portion of the first layer <NUM>. An inner surface of the first layer <NUM> defines the shaft lumen <NUM>. The first layer <NUM> can comprise a lubricious polymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such as perfluoroalkoxy alkanes (PFA) (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM> such as, for example, PEBA, PVC, PE, etc. In other embodiments, the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers, etc.) depending upon the desired characteristics of the catheter <NUM>. In some embodiments the first and second layers <NUM>, <NUM> have generally the same lengths and are coextensive along the length of the shaft <NUM>, and in other embodiments the first and second layers <NUM>, <NUM> have different lengths and/or are not coextensive along the shaft <NUM>. For example, in a particular embodiment, the second layer <NUM> extends along only a portion of the length of the shaft <NUM> while the first layer <NUM> extends the entire length (or substantially the entire length) of the shaft <NUM>. In any of the above embodiments, the first layer <NUM> can have a thickness of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches), or about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). Also, in any of the above embodiments, the second layer <NUM> can have a thickness of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches), or about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches).

In some examples, the stiffness of the inner polymer structure <NUM> can be generally uniform along its length, or the stiffness can vary along its length. The stiffness variation is a function of the size, shape, thickness, and/or materials of the inner polymer structure <NUM>. In embodiments where the stiffness of the inner polymer structure <NUM> varies along its length, the stiffness can change continuously (e.g., gradually) and/or be stepped from one section to another. The stiffness of the inner polymer structure <NUM> decreases in a proximal to distal direction along its length. In other examples described herein, the stiffness of the inner polymer structure <NUM> increases in a proximal to distal direction along it length, and/or increases and decreases in a proximal to distal direction along its length. Additionally, the inner polymer structure <NUM> can be made of or include a radiopaque material for radiographic visualization. Exemplary radiopaque materials include, for example, gold, platinum, palladium, tantalum, tungsten alloy, polymer materials loaded with radiopaque fillers, and the like. Likewise, in some embodiments, the inner polymer structure <NUM> is made of or include a material that may aid in MRI imaging, such as, for example, tungsten, Elgiloy, MP35N, nitinol, and others.

In the embodiment shown in <FIG>, the outer polymer structure <NUM> directly contacts at least a portion of the inner polymer structure <NUM> and encases at least a portion of each of the inner braid <NUM>, the outer braid <NUM>, and the coil <NUM>. The outer polymer structure <NUM> extends distally from the proximal portion 106a of the shaft <NUM> to a location within the distal portion 106b of the shaft <NUM> (e.g., the entire length of the shaft <NUM> or substantially the entire length of the shaft <NUM>). The length of the outer polymer structure <NUM> can vary depending upon, for example, the length of the shaft <NUM> and the desired characteristics and functions of the catheter <NUM>. In some embodiments, the outer polymer structure <NUM> extends substantially the entire length of the shaft <NUM>. In other embodiments, the outer polymer structure <NUM> extends along only a portion of the length of the shaft <NUM> and/or has a proximal and/or distal terminus that does not correspond to a proximal terminus and/or distal terminus, respectively, of the shaft <NUM>.

The outer polymer structure <NUM> (and/or portions thereof) can be made of any suitable polymer (or composites or combinations thereof) and by any suitable process. Suitable polymers can include, for example, polyoxymethylene (POM), polybutylene terephthalate (PBT), polyether block ester, polyether block amide (PEBA), fluorinated ethylene propylene (FEP), polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyurethane, polytetrafluoroethylene (PTFE), polyether-ether ketone (PEEK), polyimide, polyamide, polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), polyether-ester, platinum, polymer/metal composites, etc., or mixtures, blends or combinations thereof. In several embodiments, the outer polymer structure <NUM> is or at least includes a lubricious polymer. In some embodiments (not shown), the outer polymer structure <NUM> includes one or more metals or metal alloys (combinations thereof). In a particular embodiment, the outer polymer structure <NUM> does not include any polymer material and solely comprises a metal and/or metal alloy.

The stiffness of the outer polymer structure <NUM> varies along its length. In such embodiments, the stiffness variation may be continuous or stepped by varying the size, shape, thickness, and/or material composition of the outer polymer structure <NUM>. For example, in the embodiment shown in <FIG>, the outer polymer structure <NUM> includes four unique portions along its length (labeled proximal to distal as first, second, third and fourth portions <NUM>, <NUM>, <NUM>, and <NUM>, respectively) in which the respective stiffnesses of the portions <NUM>, <NUM>, <NUM>, <NUM> decrease sequentially in a proximal to distal direction. For example, the first portion <NUM> has a first stiffness, the second portion <NUM> has a second stiffness less than the first stiffness, the third portion <NUM> has a third stiffness less than the second stiffness, and the fourth portion <NUM> has a fourth stiffness less than the third stiffness. In other embodiments, the stiffness of the outer polymer structure <NUM> and/or the stiffnesses of the individual portions <NUM>, <NUM>, <NUM>, <NUM> can increase in a proximal to distal direction (e.g., the second portion <NUM> can be stiffer than the first portion <NUM>, etc.), increase and decrease in a proximal to distal direction (e.g., the second portion <NUM> can be stiffer than the first portion <NUM> but less stiff than the third portion <NUM>, etc.), or be generally uniform in a proximal to distal direction. In other embodiments, the outer polymer structure <NUM> can have more or fewer portions (e.g., one continuous portion, two portions, three portions, five portions, etc.).

In some embodiments, one or both of the first and second portions <NUM>, <NUM> can have an individual thickness of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches), and in some embodiments, about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). The fourth portion <NUM> can have a thickness of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). The proximal portion of the tapered portion <NUM> can have a thickness equivalent to that of the corresponding second portion <NUM>, and the distal portion of the tapered portion <NUM> can have a thickness generally equivalent to that of the corresponding fourth portion <NUM>. Thus, the third portion <NUM> can have a proximal thickness between about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches), or in some embodiments about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches), and a distal portion have a thickness of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches).

The portions <NUM>, <NUM>, <NUM>, <NUM>, either individually or any combination thereof, can be made of the same or different materials, have the same or different size, have the same or different thickness, and/or have the same or different cross-sectional shape. In some embodiments, the outer polymer structure <NUM> can include two or more layers (e.g., an inner layer surrounding an outer layer, etc.), and each layer can have the same or different material compositions, thicknesses, and/or stiffnesses. Additionally, the portions <NUM>, <NUM>, <NUM>, <NUM>, either individually or any combination thereof, can have a uniform or varying stiffness along its respective length. In other words, the portions <NUM>, <NUM>, <NUM>, <NUM>, either individually or any combination thereof, can have a uniform or varying size, shape, thickness, and/or material composition along its respective length. For example, in the embodiment shown in <FIG>, each of the portions <NUM>, <NUM>, <NUM>, <NUM> has a constant material composition and cross-sectional shape along its respective length. Each of the first, second, and fourth portions <NUM>, <NUM>, <NUM> also has a generally constant thickness along its respective length; accordingly, each of the first, second, and fourth portions <NUM>, <NUM>, <NUM> has a generally constant stiffness along its respective length. The third portion <NUM>, however, includes the tapered portion <NUM> (<FIG>) and thus varies in thickness (and stiffness) along its length. In other embodiments, the third portion <NUM> does not coincide with the tapered portion <NUM> and/or the tapered portion <NUM> spans more than one of the portions <NUM>, <NUM>, <NUM>, <NUM>.

It will be appreciated that while the inner polymer structure <NUM> and the outer polymer structure <NUM> are described herein as separate components with respect to the illustrated embodiments, the inner and outer polymer structures <NUM>, <NUM> can be provided as a single layer or structure. For example, the inner polymer structure <NUM> and outer polymer structure <NUM> may be provided separately, but attached or combined together to physically form a single layer (e.g., a single homogeneous material).

Referring still to the embodiment shown in <FIG>, the inner braid <NUM> is on and around the inner polymer structure <NUM>, and the outer polymer structure <NUM> is on and around the inner braid <NUM>. In some embodiments, the inner braid <NUM> directly contacts at least a portion of both the inner polymer structure <NUM> and the outer polymer structure <NUM>. In other embodiments, the outer polymer structure <NUM> is between at least a portion of the inner polymer structure <NUM> and at least a portion of the inner braid <NUM>. In the embodiment shown in <FIG>, the inner braid <NUM> extends distally from the proximal portion 106a of the shaft <NUM> to a distal terminus 160b aligned with or just proximal of the distal terminus of the shaft <NUM>. In other embodiments, the inner braid <NUM> extends the entire length of the shaft <NUM>. The length of the inner braid <NUM> can vary depending upon, for example, the length of the shaft <NUM> and the desired characteristics and functions of the catheter <NUM>.

In some embodiments, at least a portion of the inner braid <NUM> is coextensive with at least a portion of the outer braid <NUM>. For example, in the embodiment shown in <FIG>, the inner braid <NUM> has a distal terminus 160b located at a position along the shaft <NUM> distal of a proximal terminus (not shown) of the outer braid <NUM> and proximal of a distal terminus 162b of the outer braid <NUM>. In other embodiments (not shown), no portion of the inner braid <NUM> is coextensive with a portion of the outer braid <NUM>. Additionally, in some embodiments at least a portion of the inner braid <NUM> is coextensive with at least a portion of the coil <NUM>, and in other embodiments the inner braid <NUM> is adjacent to and/or spaced apart from the coil <NUM> along the length of the shaft <NUM>. For example, in the embodiment shown in <FIG>, the distal terminus 160b of the inner braid <NUM> is located at a position along the shaft <NUM> proximal of a proximal terminus 170a of the coil <NUM> such that no portion of the inner braid <NUM> is coextensive with any portion of the coil <NUM>. Alternatively, in some embodiments (not shown) the distal terminus 160b of the inner braid <NUM> is located at a position along the shaft <NUM> distal of a proximal terminus 170a of the coil <NUM> such that at least a portion of the inner braid <NUM> is coextensive with at least a portion of the coil <NUM>.

In the embodiment shown in <FIG>, the outer braid <NUM> is around the inner braid <NUM>, and the outer polymer structure <NUM> contacts the outer braid <NUM>. In some embodiments the outer braid <NUM> directly contacts the inner braid <NUM>. In other embodiments, the outer polymer structure <NUM> is between at least a portion of the inner braid <NUM> and at least a portion of the outer braid <NUM>. In the embodiment shown in <FIG>, a distal portion of the outer braid <NUM> is around a proximal portion of the coil <NUM>. In some embodiments the outer braid <NUM> directly contacts the coil <NUM>. In other embodiments, the outer polymer structure <NUM> is between at least a portion of the outer braid <NUM> and at least a portion of the coil <NUM>.

The outer braid <NUM> extends distally from the proximal portion 106a of the shaft <NUM> to a distal terminus 162b proximal to the distal terminus of the shaft <NUM>. In other embodiments, the outer braid <NUM> extends the entire length of the shaft <NUM>. The length of the outer braid <NUM> can vary depending upon, for example, the length of the shaft <NUM> and the desired characteristics and functions of the catheter <NUM>. In some embodiments, at least a portion of the outer braid <NUM> is coextensive with at least a portion of the coil <NUM>. For example, in the embodiment shown in <FIG>, the distal terminus 162b of the outer braid <NUM> is located at a position along the shaft <NUM> that is distal of the proximal terminus 170a of the coil <NUM>. In those embodiments where at least a portion of the outer braid <NUM> is coextensive with at least a portion of the coil <NUM>, the coextensive portions of the outer braid <NUM> and the coil <NUM> form an overlapping region <NUM>. As shown in <FIG>, in some embodiments the outer braid <NUM> surrounds the coil <NUM> within the overlapping region <NUM>. In other embodiments, the coil <NUM> surrounds the outer braid <NUM> within the overlapping region <NUM> (<FIG>, described in greater detail below). In yet other embodiments, the outer braid <NUM> is spaced apart from and/or adjacent to the coil <NUM> such that no portion of the outer braid <NUM> is coextensive with any portion of the coil <NUM>.

The inner braid <NUM> and/or the outer braid <NUM> can individually have a generally uniform pitch along its respective length or may have a varying pitch along its respective length. The flexibility of the individual inner braid <NUM> and/or the outer braid <NUM> may vary continuously along its respective length by continuously varying the pitch or may vary along its respective length in a stepwise fashion by stepwise varying the pitch. Moreover, the inner braid <NUM> and/or the outer braid <NUM> can individually have a generally constant braid angle along its respective length or have a varying braid angle along its respective length to provide different zones of stiffness and/or flexibility. The inner braid <NUM> and/or the outer braid <NUM> can be formed of braided filaments having the same or varying diameters (individually and/or relative to the other braid). In some embodiments, the inner braid <NUM> and/or the outer braid <NUM> are further shaped using a heat setting process. Additionally, the inner braid <NUM> and the outer braid <NUM> can have the same or different pitch, stiffness, braid angle, filament diameters, and filament count. In some embodiments, the inner and/or outer braids <NUM>, <NUM> individually have a pitch of <NUM> picks per centimeter (<NUM> picks per inch (PPI) to <NUM> picks per centimeter (<NUM> PPI). In a particular embodiment, the shaft <NUM> includes a single braid. Additionally, in some embodiments, the inner braid <NUM> and/or the outer braid <NUM> can be made of or include a radiopaque or imaging material.

The inner <NUM> and/or outer braids <NUM> are formed of a plurality of interwoven wires. The wires can have a circular or rectangular cross-sectional shape. The wires can be made of one or more metals, such as stainless steel, platinum, silver, tantalum, and the like. In some embodiments, the wires can include or be made of non-metallic materials. In some embodiments, the wires are made of a superelastic or shape-memory material, such as nitinol. For those embodiments utilizing wires having a rectangular shape, the wires can have a cross-sectional area of about <NUM> millimeters (about <NUM> inches) by <NUM> millimeters (<NUM> inches) to about <NUM> millimeters (about <NUM> inches) by <NUM> millimeters (<NUM> inches).

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>. In the embodiment shown in <FIG>, the outer polymer structure <NUM> encases the coil <NUM>. The proximal terminus 170a of the coil <NUM> is positioned along the distal portion 106b of the shaft <NUM>, and the distal terminus 170b of the coil <NUM> is positioned generally in alignment with or just proximal to the distal terminus of the shaft <NUM>. Accordingly, the coil <NUM> is completely disposed within the distal portion of the shaft. In other embodiments, at least a portion of the coil <NUM> is outside of the distal portion 106b of the shaft <NUM>. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion. The pitch of the coil <NUM> varies along the length of the coil <NUM>. The coil <NUM> can have a pitch of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). In some embodiments, the pitch of the coil <NUM> depends on the inner diameter of the shaft <NUM>. For example, for a shaft inner diameter of about <NUM> millimeters (about <NUM> inches), the coil <NUM> can have a pitch of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). For a shaft inner diameter of about <NUM> millimeters (about <NUM> inches), the coil <NUM> can have a pitch of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). For a shaft inner diameter of about <NUM> millimeters (about <NUM> inches), the coil <NUM> can have a pitch of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). For a shaft inner diameter of about <NUM> millimeters (about <NUM> inches), the coil <NUM> can have a pitch of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches). Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

The wire of the coil <NUM> can be made of one or more metals, such as stainless steel, platinum, silver, tantalum, and the like. In other embodiments, the wire of the coil <NUM> can include or be made of non-metallic materials. In a particular embodiment, the wires are made of a superelastic or shape-memory material, such as nitinol The wire can have an outer diameter of about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches), or in some embodiments about <NUM> millimeters (about <NUM> inches) to about <NUM> millimeters (about <NUM> inches).

It will be appreciated that the inner braid <NUM>, outer braid <NUM>, and coil <NUM> can have other suitable configurations and/or relative positions along the length of the shaft <NUM>. For example, in some embodiments the inner braid <NUM> can be coextensive with at least a portion of the coil <NUM>, and in some embodiments the inner braid <NUM> can be generally coextensive with the outer braid <NUM>. In a particular embodiment, at least a portion of the outer braid <NUM> is not coextensive with a portion of the coil <NUM>.

<FIG> is a cross-sectional side view of a portion of a catheter shaft <NUM> configured in accordance with another embodiment of the present technology. The shaft <NUM> can be generally similar to the shaft <NUM> shown in <FIG>, except the coil <NUM> in the shaft <NUM> of <FIG> surrounds the outer braid <NUM> within the overlapping region <NUM>.

<FIG> are cross-sectional side views of distal portions of catheter shafts configured in accordance with the present technology. Any of the distal portions (or aspects thereof) described below can included in embodiments of the invention and may be combined with any of the catheter shafts described above with reference to <FIG> as defined in the appended claims. As described in greater detail below, the distal portion embodiments of the present technology include regions of varying stiffness and/or preferential bending that provide improved bending/buckling at the distal portion when contacting the wall of tortuous vessels, thereby improving ease of navigation of the corresponding shaft and/or distal portion.

<FIG> is a cross-sectional side view of a distal portion <NUM> of a catheter shaft. The distal portion <NUM> can include a radiopaque marker <NUM>, an inner polymer structure <NUM>, an outer polymer structure <NUM> surrounding at least a portion of the inner polymer structure <NUM>, and a coil <NUM> wrapped around at least a portion of the inner polymer structure <NUM>. As shown in <FIG>, the inner polymer structure <NUM> extends the length of the distal portion <NUM> such that the inner polymer structure <NUM> terminates distally at an opening <NUM> at the distal terminus of the distal portion <NUM>. The inner polymer structure <NUM> defines a lumen that can be generally continuous with the lumen <NUM> of any of the shaft embodiments described above with reference to <FIG>.

The inner polymer structure <NUM> can include a single layer of material or it can have two or more layers of the same or different materials. For example, in <FIG>, the inner polymer structure <NUM> includes a first layer <NUM> and a second layer <NUM> surrounding the first layer <NUM>. Accordingly, an inner surface of the first layer <NUM> defines the shaft lumen <NUM> at the distal portion <NUM>. The first layer <NUM> can comprise a lubricious polymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such as PFA (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM>. Moreover, in some embodiments the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers) depending on the desired characteristics of the distal portion <NUM> of the catheter.

In some examples, the stiffness of the inner polymer structure <NUM> can be generally uniform along its length, or the stiffness can vary along its length. In <FIG>, the second layer <NUM> of the inner polymer structure <NUM> includes two unique portions along its length (labeled proximal to distal as first portion <NUM> and second portion <NUM>). The first and second portions <NUM>, <NUM> can have at least one of a different size, shape, thickness, and material composition such that the first portion <NUM> has a different stiffness than the second portion <NUM> (or in other words, the second portion <NUM> is softer than the first portion <NUM>). For example, the first portion <NUM> can be a first material and the second portion <NUM> can be a second material different than the first material such that a stiffness of the first portion <NUM> is greater than a stiffness of the second portion <NUM>. In other examples, a stiffness of the inner polymer structure <NUM> can increase in a proximal to distal direction along its length, or increase and decrease in a proximal to distal direction along its length. For example, the second portion <NUM> can have a stiffness that is greater than or equal to the stiffness of the first portion <NUM>. In other examples, the inner polymer structure <NUM> can have more or fewer portions (e.g., one continuous portion, three portions, four portions, etc.).

In <FIG>, both the first and second layers <NUM>, <NUM> of the inner polymer structure <NUM> extend along the entire length of the distal portion <NUM> such that the distal termini of both the first and second layers <NUM>, <NUM> are at the distal terminus of the distal portion <NUM>. Additionally, the second portion <NUM> of the second layer <NUM> defines a portion of the distal terminus of the distal portion <NUM> of the shaft. As such, the distal-most surfaces of both the inner and the outer polymer structures <NUM>, <NUM> define the distal terminus of the distal portion <NUM> of the shaft. In other embodiments, the first layer <NUM> terminates proximal to the distal terminus of the distal portion <NUM>.

Although the inner polymer structure <NUM> is shown having two portions <NUM>, <NUM> in <FIG>, in other examples, the inner polymer structure <NUM> may have a single continuous portion or may have more than two portions (e.g., three portions, four portions, etc.). Moreover, although the second layer <NUM> is shown having multiple portions, in other embodiments the first layer <NUM> can additionally or alternatively include multiple portions.

Referring still to <FIG>, the outer polymer structure <NUM> directly contacts at least a portion of the inner polymer structure <NUM> and encases at least a portion of the coil <NUM>. For example, in <FIG>, at least a portion of the surface of the coil <NUM> directly contacts the first and second portions <NUM>, <NUM> of the second layer <NUM> of the inner polymer structure <NUM>, while a remaining portion of the coil's surface directly contacts the outer polymer structure <NUM>. Additionally, the outer polymer structure <NUM> extends along the length of the distal portion <NUM> such that a distal terminus of the outer polymer structure <NUM> corresponds to the distal terminus of the distal portion <NUM>. In other embodiments, the outer polymer structure <NUM> extends along only a portion of the length of the distal portion <NUM> and/or has a proximal and/or distal terminus that does not correspond to a proximal terminus and/or distal terminus, respectively, of the distal portion <NUM>. Moreover, the outer polymer structure <NUM> (and/or portions thereof) can be made of any of the materials described above with respect to the outer polymer structure <NUM>.

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>, and the outer polymer structure <NUM> can encase at least a portion of the coil <NUM>. The coil <NUM> can extend all or a portion of the length of the distal portion <NUM>. For example, in <FIG>, the coil <NUM> has a distal terminus that is aligned with or just proximal of the radiopaque marker <NUM>, and the radiopaque marker <NUM> is proximal of the distal terminus of the distal portion <NUM>. As such, a distal terminus of the coil <NUM> is spaced apart from a distal terminus of the shaft. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion as defined in the appended claims. Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

<FIG> is a cross-sectional side view of a distal portion <NUM> of a catheter shaft configured in accordance with the present technology. The distal portion <NUM> can include a radiopaque marker <NUM>, an inner polymer structure <NUM>, an outer polymer structure <NUM> surrounding at least a portion of the inner polymer structure <NUM>, and a coil <NUM> wound around at least a portion of the inner polymer structure <NUM>. The inner polymer structure <NUM> defines a lumen that can be generally continuous with the lumen <NUM> of any of the shaft embodiments described above with reference to <FIG>.

The inner polymer structure <NUM> can include a single layer of material or it can have two or more layers of the same or different materials. For example, in <FIG>, the inner polymer structure <NUM> includes a first layer <NUM> and a second layer <NUM> surrounding the first layer <NUM>. Accordingly, an inner surface of the first layer <NUM> defines the shaft lumen <NUM> at the distal portion <NUM>. The first layer <NUM> can comprise a lubricious polymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such as PFA (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM>. Moreover, in some embodiments the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers) depending upon the desired characteristics of the catheter.

In other examples described herein, the stiffness of the inner polymer structure <NUM> can be generally uniform along its length, or the stiffness can vary along its length. In <FIG>, the second layer <NUM> of the inner polymer structure <NUM> includes two unique portions (labeled proximal to distal as first portion <NUM> and second portion <NUM>) adjacent one another along its length having different stiffnesses. The first and second portions <NUM>, <NUM> can have at least one of a different size, shape, thickness, and material composition such that the first portion <NUM> has a different stiffness than the second portion <NUM>. For example, the first portion <NUM> can be a first material and the second portion <NUM> can be a second material different than the first material such that a stiffness of the first portion <NUM> is greater than a stiffness of the second portion <NUM>. In alternative examples described herein, a stiffness of the inner polymer structure <NUM> can increase in a proximal to distal direction along its length, or increase and decrease in a proximal to distal direction along its length, such as for example, where the second portion <NUM> has a stiffness that is greater than or equal to the stiffness of the first portion <NUM>.

In <FIG>, the second layer <NUM> of the inner polymer structure <NUM> extends along only a portion of the length of the distal portion <NUM> such that a distal terminus of the second layer <NUM> is proximal of the distal terminus of the outer polymer structure <NUM> and the distal terminus of the distal portion <NUM>. Accordingly, in contrast to <FIG>, only the distal-most portions of the outer polymer structure <NUM> and the first layer <NUM> define the distal terminus of the distal portion <NUM> of the shaft (and not the second layer <NUM>). Likewise, a distal region <NUM> of the distal portion <NUM> does not include the second layer <NUM> and comprises only the first layer <NUM>, the outer polymer structure <NUM>, the radiopaque marker <NUM>, and a portion of the coil <NUM>. Accordingly, the distal region <NUM> is more flexible than the remainder of the distal portion <NUM>. In some embodiments, the first layer <NUM> and/or the coil <NUM> terminates proximal of the distal region <NUM> such that the distal region <NUM> comprises the first layer <NUM> and the outer polymer structure <NUM>. The length of the distal region <NUM> can be between about <NUM> and about <NUM>.

The inner polymer structure <NUM> is shown having two portions <NUM>, <NUM> in <FIG>. In other examples the inner polymer structure <NUM> can have a single continuous portion or may have more than two portions (e.g., three portions, four portions, etc.). Moreover, although the second layer <NUM> is shown having multiple portions, in other embodiments the first layer <NUM> can additionally or alternatively include multiple portions.

Referring still to <FIG>, the outer polymer structure <NUM> directly contacts at least a portion of the inner polymer structure <NUM> and encases at least a portion of the coil <NUM>. For example, in <FIG>, at least a portion of the surface of the coil <NUM> directly contacts the inner polymer structure <NUM>, while a remaining portion of the coil's surface directly contacts the outer polymer structure <NUM>. As shown in <FIG>, in some embodiments the outer polymer structure <NUM> extends along the length of the distal portion <NUM> such that a distal terminus of the outer polymer structure <NUM> corresponds to the distal terminus of the distal portion <NUM>. The outer polymer structure <NUM> (and/or portions thereof) can be made of any of the materials described above with respect to the outer polymer structure <NUM>.

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>. The coil <NUM> can extend all or a portion of the length of the distal portion <NUM>. For example, in <FIG>, the coil <NUM> has a distal terminus that is aligned with or just proximal of the radiopaque marker <NUM>, and the radiopaque marker <NUM> is proximal of the distal terminus of the distal portion <NUM>. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion. Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

The distal portions <NUM>/<NUM> provide several advantages over distal portions of conventional catheters, especially microcatheters for delivering occlusive devices (such as coils) to cerebral aneurysms. For example, the distal portions <NUM> and <NUM> have a (relatively) softer distal tip and a (relatively) stiffer region immediately adjacent and proximal to the softer distal tip. Such a construction allows for improved bending and trackability at the distal tip bend (for positioning at the aneurysm neck) while the proximal stiffer region of the distal portion <NUM>/<NUM> provides additional support and stability to the distal portion <NUM>/<NUM>, thereby lessening or preventing kickback of the shaft during deployment of an occlusive device (such as a coil) in an aneurysm.

<FIG> is a cross-sectional side view of a distal portion <NUM> of a catheter shaft configured in accordance with the present technology. The distal portion <NUM> can include a radiopaque marker <NUM>, an inner polymer structure <NUM>, an outer polymer structure <NUM> surrounding at least a portion of the inner polymer structure <NUM>, and a coil <NUM> wound around at least a portion of the inner polymer structure <NUM>. In <FIG>, the inner polymer structure <NUM> extends the length of the distal portion <NUM> such that the inner polymer structure <NUM> terminates distally at an opening <NUM> at the distal terminus of the distal portion <NUM>. The inner polymer structure <NUM> defines a lumen that can be generally continuous with the lumen <NUM> of any of the shaft embodiments described above with reference to <FIG>.

The inner polymer structure <NUM> can include a single layer of material or it can have two or more layers of the same or different materials. For example, in <FIG>, the inner polymer structure <NUM> includes a first layer <NUM> and a second layer <NUM> surrounding the first layer <NUM>. As such, an inner surface of the first layer <NUM> defines the shaft lumen <NUM>. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM>. The first layer <NUM> can comprise a lubricious polymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such as PFA (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, in some embodiments the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers) depending upon the desired characteristics of the device.

The outer polymer structure <NUM> directly contacts at least a portion of the inner polymer structure <NUM> and encases at least a portion of the coil <NUM>. For example, in <FIG>, at least a portion of the surface of the coil <NUM> directly contacts the second layer <NUM> of the inner polymer structure <NUM>, while a remaining portion of the coil's surface directly contacts the outer polymer structure <NUM>. As shown in <FIG>, in some embodiments the outer polymer structure <NUM> extends along the length of the distal portion <NUM> such that a distal terminus of the outer polymer structure <NUM> corresponds to the distal terminus of the distal portion <NUM>. The outer polymer structure <NUM> (and/or portions thereof) can be made of any of the materials described above with respect to the outer polymer structure <NUM>.

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>. The coil <NUM> can extend all or a portion of the length of the distal portion <NUM>. For example, in <FIG>, the coil <NUM> has a distal terminus that is aligned with or just proximal of the radiopaque marker <NUM>, and the radiopaque marker <NUM> is proximal of the distal terminus of the distal portion <NUM>. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion. The pitch of the coil <NUM> can be the same or vary along the length of the coil <NUM> in some of the examples described herein. For example, as in the alternative example shown in <FIG>, the coil <NUM> has a first portion <NUM> and a second portion <NUM> distal of the first portion <NUM>. The first portion <NUM> has a first pitch and the second portion <NUM> has a second pitch that is greater than the first pitch. Accordingly, a length of the distal portion <NUM> corresponding to the first portion <NUM> of the coil <NUM> is less flexible than a length of the distal portion <NUM> corresponding to the second portion <NUM> of the coil <NUM>. Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

The inner polymer structure <NUM> can include a single layer of material or it can have two or more layers of the same or different materials. For example, as shown in <FIG>, the inner polymer structure <NUM> can include a first layer <NUM> and a second layer <NUM> surrounding the first layer <NUM>. As such, an inner surface of the first layer <NUM> defines the shaft lumen <NUM>. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM>. The first layer <NUM> can include a lubricious polymer such as HDPE or PTFE, for example, or a copolymer of tetrafluoroethylene with perfluoroalkyl vinyl ether (PFA) (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, in some embodiments the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers) depending upon the desired characteristics of the device.

The outer polymer structure <NUM> directly contacts at least a portion of the inner polymer structure <NUM> and encases at least a portion of the coil <NUM>. For example, in <FIG>, at least a portion of the surface of the coil <NUM> directly contacts the second layer <NUM> of the inner polymer structure <NUM>, while a remaining portion of the coil's surface directly contacts the outer polymer structure <NUM>. In some embodiments the outer polymer structure <NUM> extends along the length of the distal portion <NUM> such that a distal terminus of the outer polymer structure <NUM> corresponds to the distal terminus of the distal portion <NUM>. The outer polymer structure <NUM> (and/or portions thereof) can be made of any of the materials described above with respect to the outer polymer structure <NUM>.

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>. The coil <NUM> can extend all or a portion of the length of the distal portion <NUM>. For example, in <FIG>, the coil <NUM> has a distal terminus that is aligned with or just proximal of the radiopaque marker <NUM>, and the radiopaque marker <NUM> is proximal of the distal terminus of the distal portion <NUM>. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion. In alternative examples described herein, the pitch of the coil <NUM> can be the same or vary along the length of the coil <NUM>. For example, in <FIG>, the coil <NUM> has a first portion <NUM>, a second portion <NUM> distal of the first portion <NUM>, and a third portion <NUM> distal of the second portion <NUM>. The first portion <NUM> has a first pitch, the second portion <NUM> has a second pitch less than the first pitch, and the third portion <NUM> has a third pitch greater than the second pitch. Accordingly, regions of the distal portion <NUM> corresponding to the first and third portions <NUM>, <NUM> of the coil <NUM> are more flexible than a region of the distal portion <NUM> corresponding to the second portion <NUM> of the coil <NUM>. The first and third pitches can be the same or different so long as the average pitch of the first and third portions <NUM>, <NUM> is less than the average pitch of the second portion <NUM>. Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

The inner polymer structure <NUM> can include a single layer of material or it can have two or more layers of the same or different materials. For example, as shown in <FIG>, the inner polymer structure <NUM> can include a first layer <NUM> and a second layer <NUM> surrounding the first layer <NUM>. As such, an inner surface of the first layer <NUM> defines the shaft lumen <NUM>. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM>. The first layer <NUM> can comprise a lubricious polymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such as PFA (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, in some embodiments the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers) depending upon the desired characteristics of the device.

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>. The coil <NUM> can extend all or a portion of the length of the distal portion <NUM>. For example, in <FIG>, the coil <NUM> has a distal terminus that is aligned with or just proximal of the radiopaque marker <NUM>, and the radiopaque marker <NUM> is proximal of the distal terminus of the distal portion <NUM>. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion. In alternative examples described herein, the pitch of the coil <NUM> can be the same or vary along the length of the coil <NUM>. For example, in <FIG>, the coil <NUM> has a first portion <NUM>, a second portion <NUM> distal of the first portion <NUM>, a third portion <NUM> distal of the second portion <NUM>, and a fourth portion <NUM> distal of the third portion <NUM>. The first portion <NUM> has a first pitch, the second portion <NUM> has a second pitch greater than the first pitch, the third portion <NUM> has a third pitch less than the second pitch, and the fourth portion <NUM> has a fourth pitch greater than each of the first and third pitches. Accordingly, regions of the distal portion <NUM> corresponding to the first and third portions <NUM>, <NUM> of the coil <NUM> are less flexible than regions of the distal portion <NUM> corresponding to the second and fourth portions <NUM>, <NUM> of the coil <NUM>.

In some examples, the first and third pitches can be generally the same, and the second and fourth pitches can be generally the same and greater than the first and third pitches. In other examples, the first and third portions <NUM>, <NUM> can have the same and/or different pitches and/or the second and fourth portions <NUM>, <NUM> can have the same and/or different pitches, so long as the average pitch of the first and third portions <NUM>, <NUM> is less than the average pitch of the second and fourth portions <NUM>, <NUM>. Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

<FIG> is a cross-sectional side view of a distal portion <NUM> of a catheter shaft configured in accordance with the present technology. The distal portion <NUM> can include a radiopaque marker <NUM>, an inner polymer structure <NUM>, an outer polymer structure <NUM> surrounding at least a portion of the inner polymer structure <NUM>, and a coil <NUM> wound around at least a portion of the inner polymer structure <NUM>. In the embodiment shown in <FIG>, the inner polymer structure <NUM> extends the length of the distal portion <NUM> such that the inner polymer structure <NUM> terminates distally at an opening <NUM> at the distal terminus of the distal portion <NUM>. The inner polymer structure <NUM> defines a lumen that can be generally continuous with the lumen <NUM> of any of the shaft embodiments described above with reference to <FIG>.

The inner polymer structure <NUM> can include two or more layers. For example, as shown in <FIG>, the inner polymer structure <NUM> can include a first layer <NUM> and a second layer <NUM> surrounding the first layer <NUM>. As such, an inner surface of the first layer <NUM> defines the shaft lumen <NUM>. The second layer <NUM> can be made of any of the materials described above with respect to the inner polymer structure <NUM>. The first layer <NUM> can comprise a lubricious polymer such as HDPE or PTFE, for example, or platinum, PEEK, PE, PP, or a copolymer of tetrafluoroethylene, such as FEP, a copolymer of tetrafluoroethylene with perfluoroethers, such as PFA (more specifically, perfluoropropyl vinyl ether or perfluoromethyl vinyl ether), or the like. Moreover, in some embodiments the inner polymer structure <NUM> can be formed of a single layer (e.g., only the first layer <NUM>, only the second layer <NUM>, etc.), and in other embodiments the inner polymer structure <NUM> can include more than two layers (e.g., three layers, four layers) depending upon the desired characteristics of the device.

The outer polymer structure <NUM> directly contacts at least a portion of the inner polymer structure <NUM> and encases at least a portion of the coil <NUM>. For example, in the embodiment shown in <FIG>, at least a portion of the surface of the coil <NUM> directly contacts the second layer <NUM> of the inner polymer structure <NUM>, while a remaining portion of the coil's surface directly contacts the outer polymer structure <NUM>. In some embodiments the outer polymer structure <NUM> extends along the length of the distal portion <NUM> such that a distal terminus of the outer polymer structure <NUM> corresponds to the distal terminus of the distal portion <NUM>. The outer polymer structure <NUM> (and/or portions thereof) can be made of any of the materials described above with respect to the outer polymer structure <NUM>.

The coil <NUM> can be one or more round wires or flat ribbons helically wound around the inner polymer structure <NUM>. The coil <NUM> can extend all or a portion of the length of the distal portion <NUM>. For example, in the embodiment shown in <FIG>, the coil <NUM> has a distal terminus that is aligned with or just proximal of the radiopaque marker <NUM>, and the radiopaque marker <NUM> is proximal of the distal terminus of the distal portion <NUM>. The pitch of adjacent turns of the coil <NUM> may be tightly wound so that each turn touches the succeeding turn or the pitch may be set such that the coil <NUM> is wound in an open fashion. In some examples described herein, the pitch of the coil <NUM> can be the same or vary along the length of the coil <NUM>. For example, in the embodiment shown in <FIG>, the coil <NUM> has a first portion <NUM>, a second portion <NUM> distal of the first portion <NUM>, and a third portion <NUM> distal of the second portion <NUM>. The first portion <NUM> has a first pitch, the second portion <NUM> has a second pitch greater than the first pitch, and the third portion <NUM> has a third pitch less than the second pitch. Accordingly, regions of the distal portion <NUM> corresponding to the first and third portions <NUM>, <NUM> of the coil <NUM> are less flexible than a region of the distal portion <NUM> corresponding to the second portion <NUM> of the coil <NUM>. In some embodiments, the first and third pitches can be the same or different so long as the average pitch of the first and third portions <NUM>, <NUM> is less than the average pitch of the second portion <NUM>. Additionally, in some embodiments, the coil <NUM> or portions thereof can be made of or include a radiopaque or imaging material.

In the embodiment shown in <FIG>, the coil <NUM> has a first portion <NUM> having a first pitch, a second portion <NUM> having a second pitch greater than the first pitch, and a third portion <NUM> have a third pitch less than the second pitch. The first and third pitches can be the same or different. The third portion <NUM> is distal of the second portion <NUM>, and the second portion <NUM> is distal of the first portion <NUM>.

The outer polymer structure <NUM> can be constructed and disposed using any appropriate technique, for example, by extrusion, co-extrusion, ILC, coating, heat shrink techniques, heat bonding, casting, molding, fusing one or several segments of an outer polymer structure material end-to-end, or the like. The outer polymer structure <NUM> can be secured to the inner polymer structure <NUM>, the coil <NUM>, the inner braid <NUM>, and/or the outer braid <NUM> by any of the above techniques. In embodiments where the outer polymer structure <NUM> is constructed independently of the other portions of the shaft <NUM>, the outer polymer structure <NUM> may be thereafter secured to the inner polymer structure <NUM>, the inner braid <NUM>, the outer braid <NUM>, and/or the coil <NUM> using suitable techniques such as adhesive bonding, crimping, friction fitting, mechanically fitting, chemically bonding, thermally bonding, welding (e.g., resistance, RF, or laser welding), soldering, brazing, or the use of a connector member or material, or the like, or combinations thereof.

Several other embodiments of the technology can have different states, components, or procedures than those described herein. Moreover, it will be appreciated that specific elements, substructures, advantages, uses, and/or other features of the embodiments described with reference to <FIG> can be suitably interchanged, substituted or otherwise configured with one another in accordance with additional embodiments of the present technology. For example, any of the distal portions described with reference to <FIG> can be combined with any of the elongated shafts and/or catheter systems described with references to <FIG>. Furthermore, suitable elements of the embodiments described with reference to <FIG> can be used as standalone and/or self-contained devices. A person of ordinary skill in the art, therefore, will accordingly understand that the technology can have other embodiments with additional elements, or the technology can have other embodiments without several of the features shown and described above with reference to <FIG>.

Claim 1:
A catheter, comprising:
an elongated shaft (<NUM>, <NUM>) having a proximal portion (106a) and a distal portion (106b, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein an inner surface of the elongated shaft defines a lumen (<NUM>) that extends distally from the proximal portion to an opening (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) at a distal terminus of the distal portion;
wherein the distal portion includes:
an inner polymer structure (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a first portion (<NUM>, <NUM>) and a second portion (<NUM>, <NUM>) positioned distal of the first portion along the length of the inner polymer structure, wherein the first portion has a first stiffness and the second portion has a second stiffness less than the first stiffness;
an outer polymer structure (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) disposed around the inner polymer structure; and
a coil (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) wound around the inner polymer structure and disposed within the outer polymer structure, characterised in that, a portion of the coil within the distal portion includes a first region (<NUM>), a second region (<NUM>) distal to the first region, and a third region (<NUM>) distal to the second region, wherein the first and third regions each have a tighter pitch than the second region.